EEVblog Electronics Community Forum
Electronics => Power/Renewable Energy/EV's => Topic started by: cdev on October 23, 2021, 03:04:40 pm
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I live in the US and like us all, I am anticipating a huge increase in gas and electricity rates due to export capacity coming on line. and anticipate really needing to save money on heat in the coming years. We have a gas boiler that heats water which is circulated through radiators. If we kept the heat on though the winter to keep the house toasty warm, it would probably cost us around $350/month now. We mosty use gas, unless its just one room we are heating (offices we spend most of our time in) To use our electric heaters now would cost a lot more) If we attempted to heat with electricity or gas it could easily cost three times as much for the same amount of heat. Triple paned windows, helped a real lot.We usually use a mix of the gas fueld hyronic heat and heating wherever we are (ceramic or oil filled electric heaters) But the cost of using electric heat adds up fast. I think that even if the price of gas triples, it will still be much cheaper than electric which is also supposed to double (the official EIA prediction) or possibly triple within the first 5 years or so depending on whether the weather is warm or cold.
Are there any gas boilers (for heating water radiators) that are particularly efficient as well as durable and long-lasting? A neighbor who sson sold her home bought a newer boiler a few years ago and the couple that are now living in that house are already replacing it because it seems to be too inefficient, and too expensive to run. It is a Rheem or American Standard unit that I think she bought and left the new owners with. The one thats sold at Home Depot. The previous owner had also made changes to her house that made it much less efficient to heat, "opened up" the living room to give it a semi cathedral ceiling, connecting both top and main floor as far as air circulation. Adding a balcont on the second floor, eliminating the room that used to take up that space, which connected the to floors as far as airflow. She also added many nice skylights.. That looks great in photos and likely aded money to the sale price substantially, ut now that house is like a furnace in the summer. but made it a LOT hotter in the summer (really really hot) and colder in the winter. So it may be the homes fault and not the heaters in this case. And they recently had a child. I should also add that it seems that my home has a very low heating bill, relative to my neighbors. Wehave also insulated our roof very well, so well when snow falls the snow on the roof does not melt. So as it stands now we are doing fairly well for energy efficiency.. We have all LED lighting the only incandescent lights are on our vent hood and in the refrigerator.
Thankfully I live on the (relatively mild climate) East Coast, (near to NYC) but, I am still a bit inland not right on the coastal plain so it still gets into the subzero temperatures sometimes. What can we do to heat more efficiently? We're currently using hot water heating with cast iron radiators and a 230 volt water pump by Bell and Gosset which I like. Its quiet and seems to me to be a good way to heat. We have an American Standard boiler from the 70s.
But now they are selling off the natural gas, and a large increase in the price of gas is expected. Everybody says prices are about to rise a lot.(~3x to start and then maybe more.) for both gas and electricity. This is because electricity's price tracks that of natural gas's. GAS will remain the cheapest source of raw energy. I'd like to stick with the hot water heat, if I can, and just get a better boiler if I can find a unit I'm confident will be worth the upgrade. My current boiler is old but reliable. It would probably last another decade or two, just left alone. But the price of all that gas is going to be going up pretty fast.
As far as efficiency Ive been told its inefficient. Ive been told its probably around 60% efficient (the one we have now) What I would like to know is if any other boilers are much more efficient. What are the technical differences between boilers that impact efficiency in turning gas into heat? My house is very small for this area, and probably less than 1500 square feet.
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60% sounds low unless it is ancient, look up what it actually is. Modern condensing boilers are close to 100%
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Have you considered air to water heat pump? Thats what everybody here seems to be replacing expensive oil heating with.
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It (the furnace) IS fairly ancient. The house was converted from oil to natural gas in the early 1970s. Some people around here those with big old houses built before World War II seem to (judging by trucks I sometimes see) still use oil. They sometimes have underground tanks which now they are supposed to remove. (which can be expensive if they have leaked)
I dont know how much using oil costs in comparison to natural gas, It might be cheaper or get cheaper in the coming years. But I would guess its burning pollutes a lot, like diesel engines, and that is not good and also might not even remain legal . So I guess that nomatter what kind you use the coming changes are going to be costly, perhaps very costly. Especially in the colder areas.
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Have you considered air to water heat pump? Thats what everybody here seems to be replacing expensive oil heating with.
The units look to be a lot more expensive than replacement boilers Ive seen so far. They also look a lot like the popular mini-split AC units.
Am I correct that they both cool and heat? Where does the heat energy come from?
If it's electricity, using electricity for the actual heat is just insane with the price increases that I understand are coming. We have natural gas running to our house and oil would have to be a lot cheaper to justify installing an oil burner. But if it saves a lot I could consider that. I hate being cold.
We already have an HVR and it saves us a lot on AC so we dont need an added cooling capability except on the fairly modest number of very hot days we have each year. (realistically) This last year we used AC maybe a total of 30 days, probably less. We have other neighbors who use it continuously through the summer, but our house is much better insulated than theirs, and with the whole house ventilation we have its very rarely needed. In our previous space we had a climate cool enough to almost never use AC - we were only a few miles from the Pacific and had a constant sea breeze during the hot months of the year. (and very often, fog just rolling in) and we didn't even own one. So we are not in the habit of using air conditioning like many are.
One thing that bothers me about AC units is the dust that accumulates in them, sucks up water and then nasty mold grows. One really needs to filter the air thats going into them of dust well to prevent lots of it from collecting and growing nasty ocher-colored (light brown, caramel colored) mold. I use very fine filters to keep it out. But to be effective at this, there are so many little things to do and keep doing, that for me, because I have health issues because of this, ACs are high maintenance. But if you dont do it they can destroy your health.
for a similar reason, condensation and mold at least here in the US with the kind of constructions most houses here have you must heat them warm enough so that condensation is not a constant problem on outward facing walls from moisture. I bet that if the cost of heating goes up a lot many Americans will get ill from mold growing due to lack of enough heating being used.
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In my area (rural Ohio), Weil-McLain boilers are common. As for circulators, I have both Armstrong (virtually identical to Bell and Gossett -- many parts are interchangeable) for the whole house per se ("main circulator"). The boiler has a Taco pump. I far prefer the Taco. The most common size is "007," but you have to get a size appropriate for your system. They are fraction HP (1/6 to 1/20), silent, and usually need no service for years. The armature and windings are wet, so there are no rotating seals to leak. I will be changing out the 1/3 HP Armstrong with a Taco next Spring. All of my pumps are 110V.
The systems have one or two bypasses from the return to the pump output. The ostensible reason for that is to heat the return to the boiler to reduce condensation in the flue. Some of the newer systems (mine is circa 1993) don't seem to have the bypasses. They don't reduce fuel gas efficiency much, but they do slow down how fast you can get, say 68° to 70° from a nighttime setting of 60° or so.
Does your system have air in it? That will reduce the pump efficiency a lot. About once a year, or when I notice a high temperature differential across a pump, I go around and let air out of the various zones.
I do like the hydronic system, but it is more complicated to work on especially if you have zones. I have 6 zones to deal with.
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To get the most efficiency out of a gas boiler, it is necessary to recover the most heat possible from the burning gas, which means to cool down the flue gas to the maximum extent possible before venting it. Modern boilers will do this more efficiently than older designs. You will need to research the specifications of what is commonly available on the US market. This is a big deal in the UK where hot water to radiators is a common heating design.
The other way to heat houses more efficiently, again common in the UK, is to fit thermostatic valves to the radiators. In unoccupied rooms you can dial down the temperature to save fuel. You also want to make sure the central heating thermostat is located in a commonly occupied area so the temperature is related more closely to the comfort of the occupants.
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From what I’ve researched, the more efficient systems are the low mass condensing boilers that sense outside temperature and modulate output temperature to minimize losses. If you’ve only got a ten degree differential between outdoor to indoor, there’s no point in pumping 160F water through your radiators as our older system did.
Most use a buffer tank to hold a quantity of heated water that is sized to your system and your radiator type(s). If it’s all low mass, buffer tanks are small, the more mass you have, as is typical with in floor radiant and older cast iron, you’ll see larger capacities used.
I recently replaced a 40 year old Weil-McClain oil fired high mass boiler in a 75x35 ranch with a Lochinvar Noble propane based system. The radiators are a combination of the typical 1970’s baseboards and one radiant zone on a slab. The system uses a 40 gallon buffer tank for heat and a 60 gallon tank for the domestic hot water. It was almost double the cost if I had just replaced the old boiler but I really wanted rid of the oil tank and it’s on track to recover the addition cost in under five years of typical use. It’s silent in operation compared to the old system and fits in the space of where the 250 gallon oil tank had been. I’m very happy with the decision.
The acceptability of heat pumps is a multi-factor answer, the largest part being your average winter temperatures. Anything with electric backup heat in colder areas will be a net loser, cost wise. In the suburban Philadelphia area where I reside, heat pumps have very poor performance for December through February as they tend to run a high percentage of their time on their backup heat source. When your electric rates are high, it simply doesn’t pay to try to extract the limited energy from the low outdoor ambient.
Having had a heat pump in my first house, I was never happy with a system dumping air into the living space that is only slightly higher than the room ambient. If I was buying a house, a heat pump based heating system would be at the absolute bottom of my choices. As for the mini-splits, they have their place for adding climate control to an addition or other appropriate situations but it sure wouldn’t appear on my list of possibilities for a whole house solution in this latitude. As always, YMMV.
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The units look to be a lot more expensive than replacement boilers Ive seen so far. They also look a lot like the popular mini-split AC units.
Am I correct that they both cool and heat? Where does the heat energy come from?
They are like mini-splits, just twice the size. They heat the water in your hydronic system so can not really be used for cooling. I looked up the climate of Pittsburgh from wikipedia, it looked rather good for these pumps so you can expect maybe four kWh of heat per one kWh of electricity. All the extra heat it pulls from outside air with the compressor.
But then I looked how much gas costs there, 8$ per 1000 cf no way any heat pump to be cheaper than that.
for a similar reason, condensation and mold at least here in the US with the kind of constructions most houses here have you must heat them warm enough so that condensation is not a constant problem on outward facing walls from moisture. I bet that if the cost of heating goes up a lot many Americans will get ill from mold growing due to lack of enough heating being used.
Now that is very important point. Around here when the energy prices did rise decades ago many chose to put additional insulation in their houses. But with bad planning end result often was condensation within the wall and bad mold growth. Very expensive to fix later often cheaper to demolish and build new one.
The acceptability of heat pumps is a multi-factor answer, the largest part being your average winter temperatures. Anything with electric backup heat in colder areas will be a net loser, cost wise. In the suburban Philadelphia area where I reside, heat pumps have very poor performance for December through February as they tend to run a high percentage of their time on their backup heat source. When your electric rates are high, it simply doesn’t pay to try to extract the limited energy from the low outdoor ambient.
Having had a heat pump in my first house, I was never happy with a system dumping air into the living space that is only slightly higher than the room ambient. If I was buying a house, a heat pump based heating system would be at the absolute bottom of my choices. As for the mini-splits, they have their place for adding climate control to an addition or other appropriate situations but it sure wouldn’t appear on my list of possibilities for a whole house solution in this latitude. As always, YMMV.
That is a common problem when too small unit is installed to save cost. But Philadelphia is quite modest temperature with mean minimum 8.6 °F. Decent minisplit operates at cop around 3 and only small reduction in output power at that temperature. So should have no problem heating year-round there as they work very well here and we have colder temps.
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Retrofitting systems can be problematical because of the way things interconnect (ie, the mold growth cited above)
I built a house in southern Michigan where temps can go as low as -20F (-28C) in the winter. I used a closed loop geothermal system and have never had to use the backup heating elements in 15 years. The house also uses a HRV that does 3-4 complete air exchanges each day. But the house was designed as a high efficiency building from the ground up. Heat losses in conventional construction might make that approach too expensive to run.
Ground source heat pumps tend to be very efficient and work well in most US climates. Even in the northern states, once you get down a couple meters in the ground the temperature is constant year round. With lots of land available you can dig trenches and bury a loop, but smaller sites can just use vertical loops done with a drilling rig.
I have an outbuilding with infloor hydronic heat provided by a Rhinai commercial tankless hot water heater. The output temp is throttled to 100F and I keep the building around 60F through the winter. I usually use around 300 gallons of propane for the entire heating season. That building is also heavily insulated. Once I get the rest of my solar arrays up, I'll probably put a geothermal unit in there too.
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The units look to be a lot more expensive than replacement boilers Ive seen so far. They also look a lot like the popular mini-split AC units.
Am I correct that they both cool and heat? Where does the heat energy come from?
They are like mini-splits, just twice the size. They heat the water in your hydronic system so can not really be used for cooling. I looked up the climate of Pittsburgh from wikipedia, it looked rather good for these pumps so you can expect maybe four kWh of heat per one kWh of electricity. All the extra heat it pulls from outside air with the compressor.
afaik heat pumps don't work very well with standard size radiators, the water isn't hot enough. You need underfloor heating or huge radiators
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The efficiency rating for boilers and furnaces is clearly specified, if you want the most efficient unit, get one with the highest efficiency you can find. With a forced air furnace it's called AFUE, I think there's a different name for the efficiency of a boiler but it's the same idea. The better units you can get today are around 98%, the pull so much heat out of the fire that the vent flue is a plastic pipe and moisture condenses out a drain. If the one you have was installed in the 1970s it could be 75% efficient or even less. If the flue vent is metal pipe it is less than 90% efficient. I just replaced a 76% efficient gas forced air furnace in my brother's place with a 98% efficient modulating furnace. Not only is it far more efficient, it's much quieter too and it runs for much longer periods at much lower output resulting in a much more even temperature.
IIRC oil is currently around double the price of natural gas.
If heating your house is costing $350 a month and your house is not a gigantic mansion or located in the arctic you should do an energy audit and consider adding more insulation. During the coldest part of winter it costs me about $80/mo to keep my ~2200sqft house 70F with a single speed 92% gas furnace.
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That is a common problem when too small unit is installed to save cost. But Philadelphia is quite modest temperature with mean minimum 8.6 °F. Decent minisplit operates at cop around 3 and only small reduction in output power at that temperature. So should have no problem heating year-round there as they work very well here and we have colder temps.
Installing too large a unit brings its own problems. Sizing of a heat pump is relatively critical, especially the traditional systems that were all single stage, single speed. In most climates it's already a compromise between heating and cooling efficiency and a system that is sized well for heating is usually oversized for cooling. Those minisplits work really well though, I helped a friend install one back in the spring and he's been really happy with it. It has inverter drives on the compressor and fans so everything ramps up and down as needed. The air blowing out still doesn't feel as warm as from a fossil fuel furnace but it heats the room nicely. The air that comes out of modern high efficiency furnaces isn't as warm as the old ones either. Another friend recently had a 3 ton Mitsubishi split system installed in his house, he said it's good all the way down to the coldest temperatures we ever get here, it has no auxiliary heat at all. No electric strips and no gas furnace, it doesn't need them.
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The units look to be a lot more expensive than replacement boilers Ive seen so far. They also look a lot like the popular mini-split AC units.
Am I correct that they both cool and heat? Where does the heat energy come from?
They are like mini-splits, just twice the size. They heat the water in your hydronic system so can not really be used for cooling. I looked up the climate of Pittsburgh from wikipedia, it looked rather good for these pumps so you can expect maybe four kWh of heat per one kWh of electricity. All the extra heat it pulls from outside air with the compressor.
But then I looked how much gas costs there, 8$ per 1000 cf no way any heat pump to be cheaper than that.
for a similar reason, condensation and mold at least here in the US with the kind of constructions most houses here have you must heat them warm enough so that condensation is not a constant problem on outward facing walls from moisture. I bet that if the cost of heating goes up a lot many Americans will get ill from mold growing due to lack of enough heating being used.
Now that is very important point. Around here when the energy prices did rise decades ago many chose to put additional insulation in their houses. But with bad planning end result often was condensation within the wall and bad mold growth. Very expensive to fix later often cheaper to demolish and build new one.
The acceptability of heat pumps is a multi-factor answer, the largest part being your average winter temperatures. Anything with electric backup heat in colder areas will be a net loser, cost wise. In the suburban Philadelphia area where I reside, heat pumps have very poor performance for December through February as they tend to run a high percentage of their time on their backup heat source. When your electric rates are high, it simply doesn’t pay to try to extract the limited energy from the low outdoor ambient.
Having had a heat pump in my first house, I was never happy with a system dumping air into the living space that is only slightly higher than the room ambient. If I was buying a house, a heat pump based heating system would be at the absolute bottom of my choices. As for the mini-splits, they have their place for adding climate control to an addition or other appropriate situations but it sure wouldn’t appear on my list of possibilities for a whole house solution in this latitude. As always, YMMV.
That is a common problem when too small unit is installed to save cost. But Philadelphia is quite modest temperature with mean minimum 8.6 °F. Decent minisplit operates at cop around 3 and only small reduction in output power at that temperature. So should have no problem heating year-round there as they work very well here and we have colder temps.
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afaik heat pumps don't work very well with standard size radiators, the water isn't hot enough. You need underfloor heating or huge radiators
Depends on the insulation, there are pretty small low temperature radiators. But if you have one of those mostly glass houses you might need more.
If you use the hydronic system for cooling too with a fan coil unit on a separate loop (the radiator loop would be turned off during cooling to prevent condensation) you could always use the FCU when it's very cold for additional heating. Not as pleasant/healthy as radiant heating, but forced air can get a lot of power through a small radiator.
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It may be more cost effective to improve the insulation of your house, including properly sealing any leaks around doors and windows.
Get used to wearing more clothes indoors and lower the temperature a few degrees.
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Any half decent gas or oil burner is like 70-100% efficient. There is not much to gain.
Failing to have large open space for air-to-air heat pump, or having the preference of water-based central heat distribution instead of multiple noisy air-to-air units:
Air to water heat pump. Works well down to some -25degC with efficient in-floor distribution, or down to some -15degC with radiator distribution.
There's a total market hysteria going on here in Finland to the point of hyperinflation in their installation prices making them financially unsound, on the top of the typical 4000-6000EUR machine itself, installation prices are now around 8000-10000EUR for a typically 8-10-hour job. The hysteria was triggered by a 4000EUR subsidy which immediately went into the installation work price but that didn't tame the hysteria so the price continued to increase even from there. The total turnkey solution price went from 8k€ to 12k€ overnight, now it's in the range of 13-18k€, 15k€ typical.
But that didn't prevent me from installing one for myself and it's working great, and pays for itself in either 4 years (assuming I get no subsidy) or instantly (assuming I do get it; let's see what happens).
In any case, air to water heat pump works great whenever your distribution system does not need high temperatures, or do so only small part of the year. I swapped some radiators to bigger, modern types. COP at air -7degC / water +35degC in my cheap Chinese EnergySave / Amitime machine is tad over 3, with defrost cycles included. But for comparison, COP at air -7 / water +45 already drops to mere 2.3 or so. At air below -20, it basically turns into direct electric heater, turning the contactor of the resistive elements on; or it can turn the oil boiler on as well. If I'd be using oil for the coldest winter days, this contraption would roughly reduce the yearly oil consumption from 2000 liters to around 200 liters. Seeing the cost of heating oil is now roughly the same as the cost of electricity, per energy, this means COP3 translates into over 60% cost savings.
Insulation improvements are good and easy investments whenever you have some other reason to open up the structures as well.
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Build a small CHP generator (the existing heating system being based on radiators makes that easier), then use the electricity to run some heat lamps. Infrared heat is very good at providing "perceived warmth" for the energy used.
Perhaps also look into solar?
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Looking at NYC climate, lowest averages are some -3degC or so. Most of the winter time heating cost is cumulated above zero degC; significant part above the defrost-requiring magical ~ +4 degC limit.. This is ideal for air source heat pumps. Don't even look at burning fossils directly or involving COP1 direct electric heating.
COP 3 is easy to achieve even in a substandard system and a well designed installation easily does COP 4.5 in such climate.
We do install them here in much colder climate (more equivalent to Canada) and still they do great savings.
Considering the capability of power generation and distribution, during worst-case cold seasons do run the gas burner. It's a small part in total cost and CO2 (because the effects are cumulative and do average out) but everybody running heatpumps with decreasing COP and increasing power consumption during the coldest weather may not be a good idea.
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In heat umps, where does the heat come from, how is it made available?
Doe heat pumps use electricity to operate?
What if the electricity goes out, how would you prevent your pipes from freezing in that situation? Can you use solar power? r does it take a lot of current like a resistive heater would to make a room toasty warm. That's what I see in our nations future and if I make a big investment that is what would like to avoid. But I have a feeling its going to become impossible to really save any real mmoney in this situation. If it was more people would be doing it. In other words, there are no free energy machines (yet?) Maybe there will be someday but I have a feeling the energy industry would do their best to get it off the market. At least here in the US. It really is like that here now. We are basically the core nexus of the cartel mentality. (Remember the light bulb cartel story?) Maybe geothermal heat in Iceland is a game changing technology. (because one can literally mine heat out of the earth in quantities sufficient to create hot water, etc. They also do that in Northern California here in the US, at Calistoga.
Look at the situation with COVID medications and vaccines.
Any half decent gas or oil burner is like 70-100% efficient. There is not much to gain.
Failing to have large open space for air-to-air heat pump, or having the preference of water-based central heat distribution instead of multiple noisy air-to-air units:
Air to water heat pump. Works well down to some -25degC with efficient in-floor distribution, or down to some -15degC with radiator distribution.
There's a total market hysteria going on here in Finland to the point of hyperinflation in their installation prices making them financially unsound, on the top of the typical 4000-6000EUR machine itself, installation prices are now around 8000-10000EUR for a typically 8-10-hour job. The hysteria was triggered by a 4000EUR subsidy which immediately went into the installation work price but that didn't tame the hysteria so the price continued to increase even from there. The total turnkey solution price went from 8k€ to 12k€ overnight, now it's in the range of 13-18k€, 15k€ typical.
But that didn't prevent me from installing one for myself and it's working great, and pays for itself in either 4 years (assuming I get no subsidy) or instantly (assuming I do get it; let's see what happens).
I
In any case, air to water heat pump works great whenever your distribution system does not need high temperatures, or do so only small part of the year. I swapped some radiators to bigger, modern types. COP at air -7degC / water +35degC in my cheap Chinese EnergySave /Amitime machine is tad over 3, with defrost cycles included. But for comparison, COP at air -7 / water +45 already drops to mere 2.3 or so. At air below -20, it basically turns into direct electric heater, turning the contactor of the resistive elements on; or it can turn the oil boiler on as well. If I'd be using oil for the coldest winter days, this contraption would roughly reduce the yearly oil consumption from 2000 liters to around 200 liters. Seeing the cost of heating oil is now roughly the same as the cost of electricity, per energy, this means COP3 translates into over 60% cost savings.
(Note: Could you explain what you mean here, a bit more, I am out of the loop, I'm sorry.)
Insulation improvements are good and easy investments whenever you have some other reason to open up the structures as well.
My neighbor's opening up (or tarting up) of her structure (which pre-makeover was virtually the same as mine) may have gotten her a higher sale price than it would have sans makeover for her prettified home, but from the new owners perspective it seems to have been a huge and expensive mistake (they said so) because of drastically increased energy loss (in winter) and gain (in summer) The small, compact houses in my neighborhood were designed in the immediate postwar era in order to give returning servicemen and women affordable "starter homes". It was a simpler era when triple paned windows had not been invented yet. Large expanses of glass and two story living rooms with fireplaces (which she added but never used) were not practical then from an energy standpoint in this part of the US.. Older houses used fireplaces made with lots of thermal mass for both production and overnight storage of heat. Homes like them are never built today except perhaps when wealthy people build them. New housing makes extensive use of composite wood products too, which require more ventilation, but here that ventilation is rarely installed, despite manufacturers warnings that it requires ventilation. New buildings around here stinks badly of formaldehyde and plastics for years. Only the most expensive homes have fireplaces and those are built it seems exclusively of brick. (the way most US housing is built today, even expensive homes, is to use standardized products.) Older homes, particularly those built in the colonial era often have innovative innovative construction, details that have disappeared now. Fireplaces in these old homes are probably much more common in old housing in Europe. I have a friend who lives in a multistry house that dates back to the 1500s, for example, The electrical hookups were added more than 100 years ago.
The core of a house then was the fireplace or hearth. They used tons of stone, as they were built to store heat from a fire, kept alight continuously for months out of every year. Many cultures had gods or more typically goddesses of the hearth. Of the home.
It seems like - concrete heating floors, for example, were used by he Romans, also extensively in Asian beds.. In northeast China and Korea, areas where firewood has been used but also, I read has been in short supply for hundreds of years, due to high population density. Until fairly modern times, family homes often contained a "kang" ( https://en.wikipedia.org/wiki/Kang_bed-stove ) customarily a hollow bed that also served as a stove and sort of chimney too, heat storage medium sleeping on it in the bitterly cold winters there. (whole families, 3 generations of families would sleep on this "kang". They are made, usually of fired brick. Or sometimes of concrete. Nowadays very few people and very little housing even there does this.
Basically most people live he same as Americans, Brits and Australians do.
I still don't understand how the heat pump technologies you are talking about works. I have a good understanding of physics..
Can you give me a short "explain it like I'm five" explanation. I can handle it.
I am worried that a smoke and mirrors act may be going on because of a desire to export commodities that have a domestic market that may not be able to afford them much longer, if demand is high elsewhere too.
I have a feeling that we have already taken care of all the low hanging fruit as far as energy savings goes, particularly when it comes to insulation goes. But we still have not done a blower door test, etc. (using negative air pressure and back pressure measurement and possibly a FLIR camera examination, to find even the small air leaks. )
Note to self, do that THIS year.
We have foam insulation, triple paned argon filled windows, LED lighting etc. The windows made a huge difference as well. They insulate so well that its been years since I have seen any condensation on our windows (except the non triple glass outside front door, which is just plain tempered glass. ) My house used to have one layer glass and metal windows that would ice up with filigree crystals in the winter from condensation. That required a lot of heat for us to stay warm.
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In heat umps, where does the heat come from, how is it made available?
Doe heat pumps use electricity to operate?
yes it requires electricity. It works just like a refrigerator except instead of moving energy from inside the fridge it outside the fridge it moves energy from outside the house to inside the house
the trickery is that it takes less energy to drive the pump than the energy it moves, so if you spend, say, 1000J running the pump and it moves 2000J you get 3000J of heat for 1000J of electricity
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OK, here's some buzzword-free thinking. (Or at least explanation of the buzzwords. Hopefully.)
If you want self-sustained safety net against long power outages, step #1 is properly insulating AT LEAST the piping. It's even better to put the effort into improving the insulating the house and run as much piping inside that insulated envelope. But at very least insulate piping so it doesn't freeze in just half a day.
But it sounds you have gone through that insulation route already.
Power outages and cold weather happens in winter when the available amount of sunlight is uncertain. If you really are worried about this situation, I don't see much other choice than storing some burnable source of energy, fossil or renewable; gas is difficult to store in large amounts, oil is easier; burning wood is always a great choice but requires some manual work. There are automated pellet solutions etc. but I wouldn't go there. Then you need some quite small amount of electrical power to run the burner, circulation pumps, etc., this could be like some 100W on average, this is possible to store in batteries overnight and get from a decent sized solar array.
Power for full electric heating under such circumstances, direct or heatpump, is practically impossible to store in batteries or generate with solar.
Yes, heat pumps run with electricity. Simplified model is, they are just electric heaters with way better than 100% efficiency. Obviously efficiency as defined by physics can't be over 100%, so the term "COP" is used instead, but for your practical purposes, it's the same. Air source heat pump extracts heating energy from outside air, even when it's colder than indoor air, cooling the outdoor air even more as result. The larger the temperature difference, the more this COP drops, and finally it reaches COP=1, that is equivalent to classic resistive heaters. But in NYC climate you would never go this far, you'd always save energy compared to resistive elements.
So let's say you need 6000W of average power to heat your home when the outside temperature is at freezing point. This 6000W could be produced by burning say 7000W worth of gas or oil or wood (because of some losses), or by consuming 6000W of electric power in direct electric (resistive) heaters placed indoor, or by consuming 2000W of electric power in a COP3 heat pump. But that 2000W would be still too much to be stored in batteries or generated by your own solar installation because likely when you most need it, it's going to be cloudy and you get maybe 500W out of your array, and only part of the day.
I'm running such hybrid solution, air-to-water heatpump does most of the job, resistive heating elements turn on automatically controlled by the heatpump when it can't sustain the power anymore (happens somewhere around -20 degC outside, I'd guess, we'll see), and, if I feel sorry for the power companies and their capability to supply, then I'll just flip some switches to use the existing oil burner instead of said resistive elements. This consumes some 100W to produce 20kW of heating power. I have some 500 liters of oil in my tank which would last for many weeks. If I run out of it, I'm not going to buy more oil, but burn wood because my boiler from 1981 supports it, too. I could add relatively small batteries and inverters to run circulation pump and oil burner if I needed to, but my home is insulated enough so that pipes don't freeze until many days without power.
Does this help?
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In heat umps, where does the heat come from, how is it made available?
Doe heat pumps use electricity to operate?
yes it requires electricity. It works just like a refrigerator except instead of moving energy from inside the fridge it outside the fridge it moves energy from outside the house to inside the house
the trickery is that it takes less energy to drive the pump than the energy it moves, so if you spend, say, 1000J running the pump and it moves 2000J you get 3000J of heat for 1000J of electricity
But if your energy is cheap it makes no sense, right?
Its kind of like selling ones rights to pollute to people who can really use it?
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... and regardless whether your target is to reduce heating bills, or reduce CO2 emissions, the Seasonal COP or SCOP of the heatpump is the right divisor. The SCOP value depends on climate, house, etc., so marketing SCOP numbers are almost always too optimistic. But the concept is valid. If you used 30000 kWh of heating energy per year and get an SCOP=3 heat pump, this drops to 10 000 kWh per year. But the drop isn't constant, in easy conditions the drop can be like 4.5x, and when it's really cold it's just 2x, but it averages out.
Expect SCOP of 3 in NYC climate with air-to-water heatpump in radiator house, or SCOP of 4 in in-floor heating house, or SCOP of 4 with air-to-air heatpumps placed in every room. Approximate values, also assuming modern high-quality heatpumps designed for heating in cold climates. Any random aircon unit with primary purpose of cooling likely isn't as efficient.
But if your energy is cheap it makes no sense, right?
Its kind of like selling ones rights to pollute to people who can really use it?
The problem as I see is the combination of very cheap fossil fuels and very expensive electricity.
Here we don't have this problem, it's pretty much 1:1 so heatpumps are immediate reduction in costs.
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In heat umps, where does the heat come from, how is it made available?
Doe heat pumps use electricity to operate?
yes it requires electricity. It works just like a refrigerator except instead of moving energy from inside the fridge it outside the fridge it moves energy from outside the house to inside the house
the trickery is that it takes less energy to drive the pump than the energy it moves, so if you spend, say, 1000J running the pump and it moves 2000J you get 3000J of heat for 1000J of electricity
But if your energy is cheap it makes no sense, right?
it might not make financial sense because a heatpump cost more than a big resistor .
Its kind of like selling ones rights to pollute to people who can really use it?
what you mean? it is just a more efficient way of turning electricity into heat. If you electricity comes from a gas fired power-plant it probably doesn't make much difference if you use gas or electricity, but if you electricity comes from from wind,solar,hydro, or even nuclear it does
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Oh, burning fossils in a modern combined cycle facility with some district heating at say 60% efficiency, then using that energy to run a heat pump at 300% COP, is waaaay better than burning the same fossils at home directly at 90% efficiency.
Add to that that electricity is never 100% from fossils, anywhere.
Electricity is relatively clean and 300% COP makes it a total no-brainer. Only politics is limiting the mass adoption of heat pumps. Politics include selling natural gas 3 times cheaper per energy than electric power.
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Oh, burning fossils in a modern combined cycle facility with some district heating at say 60% efficiency, then using that energy to run a heat pump at 300% COP, is waaaay better than burning the same fossils at home directly at 90% efficiency.
here the relatively old coal fired powerplant is 47% efficiency when making just electricity, it also supplies district heating so when the mix is right efficiency is ~90%
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Am I correct that they both cool and heat?
Reversible air to water heat pumps can, but they will need fan coil units to also do cooling. They also need radiators with low enough thermal resistance to the room they can heat it to 20c with ~45c water temperature on a cold day.
Where does the heat energy come from?
A heat pump, pumps heat. For an air to water heatpump, the heat comes out of the outside air. As long as the delta-t is small enough this is more efficient than just resistive heating.
If it's electricity, using electricity for the actual heat is just insane with the price increases that I understand are coming.
Everything is getting expensive.
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I like using natural gas for heating, I have a dual fuel system with a heat pump too but when it gets colder out I prefer the warmer air from the gas heat and I really dislike the defrost cycles that the heat pump does in cold weather. I need gas to my house anyway since I use it for cooking, electric resistance stoves suck and I've never heard of a heat pump stove. Another big advantage of gas heat is I can run my furnace along with the rest of my house on my little 2kW inverter generator during power outages which almost always happen during the winter storm season. I'd need a much larger generator to run my heat pump.
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Yes, a hybrid like that makes a lot of sense and has a potential of reducing heating cost and CO2 footprint by some 50-70% easily.
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In heat umps, where does the heat come from, how is it made available?
A heat pump is identical to an air conditioner with one difference, it adds a reversing valve and a second refrigerant metering device that enables it to reverse the refrigeration cycle. In the summer it works as an air conditioner, refrigerating the inside of your house and exhausting the heat outside. In the winter the cycle reverses, the evaporator becomes the condenser and vice versa, it refrigerates the outdoors exhausting warm air into your house. Refrigerant boils at a very low temperature so it is able to extract heat from the environment even when it is very cold outside.
Technically speaking, an air conditioner is a type of heat pump already, it works by pumping heat from inside your house to the outside. The name "heat pump" is just usually reserved for the reversible systems in order to differentiate them from air conditioners that provide cooling.
If you have a decent understanding of physics already, look up "refrigeration cycle" if you are not already familiar with the principal and the pieces should all fall into place, it's simple physics.
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I really dislike the defrost cycles that the heat pump does in cold weather.
On principle, for the meltwater or for the interruption? Most of the systems here recommend a buffer tank any way.
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Many years back, there was a heat pump in development that embedded a wire inside the outdoor coil and energized it with a burst of high power RF to cause some frost to flash to steam and blow out the remaining frost, so the defrost cycles only took a short time and did not use much energy. Not sure what it would take for it to get to market.
What if the electricity goes out, how would you prevent your pipes from freezing in that situation?
Cheapest solution to add to an existing building is a hot water recirculating pump, uses something like 10W to circulate hot water back into the cold at the faucet farthest away from the water heater (will need one for each "branch" in the plumbing). It doesn't even need to run all the time, making it trivial to run from batteries with a thermostat on the pipe switching it on as needed. The thermal capacity of the water heater will last well into days or weeks depending on how well the pipes are insulated.
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What if the electricity goes out, how would you prevent your pipes from freezing in that situation?
Electricity is needed for circulation of heat carrier liquid in ANY kind of system, unless you are heating your house with fireplace. In case you are afraid of electricity or heat source going out - fill your heating system with antifreeeze.
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With a buffer and 50% propylene glycol that's quite a bit of extra money.
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I really dislike the defrost cycles that the heat pump does in cold weather.
On principle, for the meltwater or for the interruption? Most of the systems here recommend a buffer tank any way.
I think we may be talking about different things. If you mention "heat pump" to an American they will assume an air source heat pump, with a ducted forced air system indoors. In heating mode the outdoor coil gets much colder than ambient and depending on conditions it can turn into a solid block of ice. It is not easy to sense when this happens, at least with traditional systems so what they typically do is initiate a defrost cycle on a timed schedule, once a defrost cycle is initiated the fan in the outdoor unit turns off and the reversing valve switches into cooling mode which then draws heat from the house (by blasting frigid air out the vents) for a few minutes to heat up the outdoor coil until a thermostatic switch activates terminating the cycle. Even with the outdoor fan shut off, air conditioning when it is 30F outside is ferociously efficient and it is really noticeable. A standard heat pump installation will have perhaps 10-20kW of electric resistance heat that comes on during the defrost cycle and that will take the edge off it but even that is not enough to completely overcome the cooling and make the air from the vents warm. With a dual fuel system like I have I try to set the balance point so it just never runs a defrost cycle because the gas furnace takes too long to fire up for it to work well to start it up during the defrost.
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What if the electricity goes out, how would you prevent your pipes from freezing in that situation?
Electricity is needed for circulation of heat carrier liquid in ANY kind of system, unless you are heating your house with fireplace. In case you are afraid of electricity or heat source going out - fill your heating system with antifreeeze.
A gas furnace or boiler and circulation pump can easily be run off a compact suitcase style inverter generator like I have. A heat pump is going to need several kW and will be 240V, which in North America in particular is going to be a much larger generator.
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Modern air source heatpumps, those that are actually designed for heating around or below freezing point, for some last 10 years, have improved defrosting quite a bit.
It's mostly a software thing.
From physics perspective, defrosting is not a problem; when condensing outdoor air from gaseous phase to liquid then ice, the latent energy comes in our advantage. When defrosting back to liquid (+ a bit of steam), we just lose that part of energy we already gained. From physics perspective, the result is the same as running continuously in a perfectly dry air with no defrosting need.
In practice, there are losses in the defrost process but that subjects it to optimization. If you run 5 minutes of defrosting every 30 minutes "just in case", it's going to be a huge loss of COP. First, it's important to reliably detect the need of defrosting. This is not too difficult, look at the difference between the evaporator coil temperature and outdoor air temperature for example, if layer of ice is blocking the airflow, this difference increases. The key is to place the sensors appropriately, or even use multiple sensors, test the shit out of the system in different conditions and finetune the algorithm.
Then the defrosting itself, it's best to use as high power as possible to do it quickly, but then it's important to stop the cycle as soon as all the ice is gone. Any excess time spent heating the outdoor air is waste.
The Big Names, mostly Japanese but also some Korean and Chinese, have managed to solve this problem pretty well. There are occasional issues like the well-known Mitsubishi Electric suddenly delivering a new series of "high-quality" "Nordic optimized" heat pumps where significant percentage has completely broken defrosting logic, but such failures happen on any field time to time.
But in reality, in modern machines, the COP drops like 0.2-0.3 units in frosting conditions, but no more than that.
And be aware that the need for defrosting begins already above the freezing point, around 3-5 degC, because the thing cools the outside air so the evaporator coil runs somewhat cooler.
Very cold air cannot hold much moisture so the amount of defrosting is reduced in very cold weather.
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With a buffer and 50% propylene glycol that's quite a bit of extra money.
You don't need to go that far, look up the difference between "freezing point" and "burst point". At freezing point, the solution starts becoming slushy, but you need to go down to "burst point" for it to actually damage pipework. 20-25% gets you far.
It's still expensive if you have large storage. I for example have a 1200 liter buffer tank. No antifreeze for me.
Besides, antifreeze worsens the thermal transfer properties of the water, with heatpumps this translates into slight COP penalty. Water pumping losses also increase due to higher viscosity; the reason why ground source systems which need antifreeze use ethanol which is less viscous than the glycols.
Then, in reality you may have a leak or need to do maintenance on the system. Then recovering the fluid and putting it back is PITA compared to just using water.
I prefer putting the money spent in antifreeze into the insulation, instead. Because finally, if you are without power for many days, domestic water pipes are going to burst anyway, you can't put antifreeze there. The same strategy works for both domestic water and heating water pipes: 1) keep inside insulated envelope of the house, 2) properly insulate pipes that are not within the house, 3) use backup heating sources, 4) in case of a long outage and no backup heating available, drain the system as the last resort.
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To get the most efficiency out of a gas boiler, it is necessary to recover the most heat possible from the burning gas, which means to cool down the flue gas to the maximum extent possible before venting it. Modern boilers will do this more efficiently than older designs. You will need to research the specifications of what is commonly available on the US market. This is a big deal in the UK where hot water to radiators is a common heating design.
The other way to heat houses more efficiently, again common in the UK, is to fit thermostatic valves to the radiators. In unoccupied rooms you can dial down the temperature to save fuel. You also want to make sure the central heating thermostat is located in a commonly occupied area so the temperature is related more closely to the comfort of the occupants.
What he said, basically. :)
60% is utterly dire by modern standards, 90-95% is now normal so long as the flow and return temperatures aren't too high (65 C and 45 C being reasonable for a modern condensing boiler). Sometimes on a retrofit you have to run them hotter than ideal to get enough heat output from small radiators, in that case you either live with just getting 85% or change to larger or finned radiators. In any case a modern gas boiler should take 35% or so off your gas bill at moderate cost.
Or a heat pump as others have discussed, subject to your electricity not being more than about 3x the cost per unit* than gas.
*Convert to the same unit, Joules, kWh, whatever. US gas is sold in therms right?
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Even with the outdoor fan shut off, air conditioning when it is 30F outside is ferociously efficient and it is really noticeable.
With a hydronic system with a buffer tank it will have less impact, 100L can source a lot of heat.
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It's still expensive if you have large storage. I for example have a 1200 liter buffer tank. No antifreeze for me.
In really cold climates a split air to water heat pump might be better, they use a refrigerant loop to the outside unit and put the water unit inside. No need to worry about the effects of freezing near the periphery at least.
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In really cold climates a split air to water heat pump might be better, they use a refrigerant loop to the outside unit and put the water unit inside. No need to worry about the effects of freezing near the periphery at least.
I have a monoblock type and don't have the slightest fear about it freezing. It seems the natural convection keeps the water running within the unit even if water pump fails or power goes out, I have tested this; this happens as long as there is some height difference between the buffer tank and the heatpump, no super long horizontal piping, and no unnecessary check valves (because the natural convection seems to start the opposite way). Besides, I have insulated the pipework almost excessively well, also added some extra insulation inside the heat pump, although the Chinese did quite acceptable job with Armaflex.
With long-term power outage, it would take ages for that 1200liter buffer tank to start freeze, and when it comes to that, it's game over anyway unless I'm physically present either burning some wood, or bleeding water off everything.
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With a hydronic system with a buffer tank it will have less impact, 100L can source a lot of heat.
Hydronic systems are rare in this part of the world, at least 95% of houses in my region have some form of forced air heating system. Most of what remains are older places with electric resistance baseboard heaters. I have only ever seen 2 or 3 houses around here with hydronic heat, I think it's a lot more common on the east coast.
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*Convert to the same unit, Joules, kWh, whatever. US gas is sold in therms right?
Yes. 1 therm is 100,000 BTU/h.
Last time I did the math, my electricity was almost 3 times the price of natural gas, so heat pump vs natural gas was pretty much a wash. I hear natural gas is supposed to increase sharply in price at some point so that might change, but then around 15% of our electricity in this region comes from burning natural gas so I expect that to go up too.
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Modern air source heatpumps, those that are actually designed for heating around or below freezing point, for some last 10 years, have improved defrosting quite a bit.
It's mostly a software thing.
Modern high efficiency systems are much better, however they have only recently started to gain some traction. The vast majority of installed heat pumps are still conventional units that have no software at all, the only electronics in the unit is the defrost timer which at least in a lot of them is just discrete logic.
I helped a friend install a Mitsubishi mini split back in the spring and that was a huge improvement but those are still expensive, especially in the larger sizes that can heat a whole house.
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OP - For heat loss, get a thermal imaging camera and evaluate the house. Even if you have to rent one, totally worth it and you can split costs with a neighbor if you do their home as well. Worst offenders are entrance doors (weatherstripping), windows (damaged seals) and shoddily installed insulation, and air leaks from sloppy carpentry.
High efficiency boilers are a money loser on maintenance. They have more sensors, more relays, more combustion chamber corrosion (acidic condensate), complicated expensive control board, plastic piping etc. which means they have a short life and you will spend more on repairs which can scuttle your savings. Condensing boilers were apparently mandated in the UK 2005 and may not have lived up to the marketing hype. Pre-check US recalls (https://www.cpsc.gov/search?search_api_fulltext=boiler&created=&created_1=&sort_bef_combine=created_DESC&f%5B0%5D=content_type%3Arecall_product) so you don't get sold an old lemon.
I have Grundfos pumps with built-in VFD in constant pressure-differential mode, it throttles the pump based on demand. This does save some electricity compared to the prior Bell&Gossett always running in spring/fall when there is no demand for heat, it's a small waste.
You'd likely have to upgrade combustion air supply - this is constant cold air coming in and making the basement cold, unless you get a damper and actuator.
For the Net-Zero homes, of all things a fireplace proved to be invaluable. Whether you're burning a lump of coal or wood, great in a zombie apocalypse to keep the house livable and augment heating. One guy I know uses coal in it all winter to save money on heating, although neighbors complain about the stink.
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I installed a condensing furnace 16 years ago and in that time it has never had a problem. I don't know why anyone would even consider an old low efficiency furnace or boiler, there's no way it will work out cheaper over time. I've heard people say the high efficiency stuff is failure prone but I haven't seen it. Modern electronics are pretty reliable and most of this stuff has around a 20 year warranty on the heat exchanger. What is the problem with plastic piping? I have replaced galvanized pipes that were clogged with mineral growths, and I've replaced galvanized B-vent flue pipes that rotted out, but I have never had to replace a plastic pipe. This sounds like the arguments I was hearing 16 years ago which have turned out to be completely baseless.
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OP - For heat loss, get a thermal imaging camera and evaluate the house. Even if you have to rent one, totally worth it and you can split costs with a neighbor if you do their home as well. Worst offenders are entrance doors (weatherstripping), windows (damaged seals) and shoddily installed insulation, and air leaks from sloppy carpentry.
This is a great suggestion, I borrowed a camera from work to do my house.
High efficiency boilers are a money loser on maintenance. They have more sensors, more relays, more combustion chamber corrosion (acidic condensate), complicated expensive control board, plastic piping etc. which means they have a short life and you will spend more on repairs which can scuttle your savings. Condensing boilers were apparently mandated in the UK 2005 and may not have lived up to the marketing hype.
The corrosive condensate and thinner heat exchangers can be an issue, though the biggest problem in the UK seems to be badly installed condensate drains that run outside with shallow slopes and freeze up. What we have had in the UK is a mass switchover to combi boilers, which are multi-function doing both wet central heating and instant water heating (to the point where the general public think a condensing boiler and a combi boiler are the same thing). These have a lot more internal complexity and often barely make it out of their 5-7 year warranty period. This may in hindsight turn out to be a mistake as it means people have spent the last decade removing stored hot water systems that are generally more suitable for heat pumps.
You'd likely have to upgrade combustion air supply - this is constant cold air coming in and making the basement cold, unless you get a damper and actuator.
Surely any new boiler would have a balanced flue? I'm pretty sure that's all we install here now, cold air is drawn from outside into the combustion chamber from an orifice co-located with the exhaust so as to ensure the same pressure despite wind, etc.
As I happen to have the manual open for another reason, here's a typical 10-15 year old UK-style condensing boiler. This particular one doesn't seem to have ever given trouble and is 90% efficient.
https://www.freeboilermanuals.com/assets/pdf/potterton/Potterton_Gold_H_Install.pdf (https://www.freeboilermanuals.com/assets/pdf/potterton/Potterton_Gold_H_Install.pdf)
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Surely any new boiler would have a balanced flue? I'm pretty sure that's all we install here now, cold air is drawn from outside into the combustion chamber from an orifice co-located with the exhaust so as to ensure the same pressure despite wind, etc.
In North America they call it "direct vent", there is an intake air pipe and a flue pipe in parallel, or occasionally coaxial. I haven't seen a condensing appliance that didn't support direct vent in well over a decade. In some cases it is permissible to configure them to draw room air for combustion but I can't think of many reasons to do that. Certainly if your furnace/boiler is located in conditioned space you would always want to use direct vent.
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As I stated in my post, the purpose of the bypass from return to source is "ostensibly" to prevent condensation in the boiler fire box caused by cold return water. That is stated in the installation and service manuals. Nevertheless, the flue gases are still cool, as the flue is barely warm. The flue is about 16' to the sidewall exhaust in my home. It is double wall stainless. There was still a problem with condensate, so I installed a flue drain like this a few several years ago: https://www.ecomfort.com/Noritz-DT4/p31848.html?gclid=EAIaIQobChMI07XWh7_m8wIVw2xvBB1C2gIEEAQYAiABEgL8E_D_BwE (https://www.ecomfort.com/Noritz-DT4/p31848.html?gclid=EAIaIQobChMI07XWh7_m8wIVw2xvBB1C2gIEEAQYAiABEgL8E_D_BwE)
No more dripping from joints. For the drain tube, I use a typical water-sealed S-bend to keeps flue gasses out of the basement. I wish Weil-McLain or other identifiable source would issue some update notice to get rid of the bypasses. (plural) Until then, I will have at least the one my boiler came with. But, that is next Summer's project.
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Only politics is limiting the mass adoption of heat pumps.
unless your in the uk were its the latest government environmentally friendly buzz word and another way to divert £450 million to there chums whilst leaving a large percentage of home owners paying higher energy bills for a system that wont keep the house as warm.
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In heat umps, where does the heat come from, how is it made available?
Doe heat pumps use electricity to operate?
yes it requires electricity. It works just like a refrigerator except instead of moving energy from inside the fridge it outside the fridge it moves energy from outside the house to inside the house
the trickery is that it takes less energy to drive the pump than the energy it moves, so if you spend, say, 1000J running the pump and it moves 2000J you get 3000J of heat for 1000J of electricity
The problem with heat pumps is that they are effectively pumping heat "uphill" and the colder it is outside, the taller the hill is. At some point the temperature difference becomes great enough that efficiency is no better than electric heating, which is 100%, but a lot more expensive than lower efficiency heating using some type of fuel. The other problem is that heat pumps are more complicated leading to higher cost and lower reliability.
One place were I lived in Southern California, with the associated mild temperatures, had a heat pump. And one winter we had an unusually cold week where the heat pump was completely useless because the outside temperature was too cold.
Power outages and cold weather happens in winter when the available amount of sunlight is uncertain. If you really are worried about this situation, I don't see much other choice than storing some burnable source of energy, fossil or renewable; gas is difficult to store in large amounts, oil is easier; burning wood is always a great choice but requires some manual work. There are automated pellet solutions etc. but I wouldn't go there. Then you need some quite small amount of electrical power to run the burner, circulation pumps, etc., this could be like some 100W on average, this is possible to store in batteries overnight and get from a decent sized solar array.
Power for full electric heating under such circumstances, direct or heatpump, is practically impossible to store in batteries or generate with solar.
After living through the January 2007 North American ice storm (https://en.wikipedia.org/wiki/January_2007_North_American_ice_storm) with no power to operate the furnace for a week, I bought backup kerosene and propane heaters, and a backup power generator.
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The problem with heat pumps is that they are effectively pumping heat "uphill" and the colder it is outside, the taller the hill is. At some point the temperature difference becomes great enough that efficiency is no better than electric heating, which is 100%, but a lot more expensive than lower efficiency heating using some type of fuel. The other problem is that heat pumps are more complicated leading to higher cost and lower reliability.
While it's true that efficiency of a heat pump drops as the outdoor temperature gets lower, I don't think it will ever quite reach parity with electric resistance heat. Even when it's very cold out, you still get most of the heat that comes from the electricity that goes into the unit. Refrigerant is used to cool the compressor and that heat ends up getting pumped into the house, plus whatever heat it is able to extract from the ambient air. Also newer units are effective down to surprisingly low temperature, I don't remember the spec from the Mitsubishi split system he had installed but I think it's supposed to be good down to -20F. His system has no auxiliary heat at all. Just about anything is more complicated than electric resistance heating, but heat pumps are not known for being unreliable, when properly installed they can be expected to last about as long as a gas furnace. They are after all just an air conditioner with a few added bits and that's a pretty mature technology. They do work best in mild climates though.
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COP1 parity will be reached in cold climates such as Northern Finland easily but I for example live in Southern parts of the country, Google up "Tampere climate" for a rough idea what we are talking about. Much colder than NYC, for example, but not that bad. Some do install ground-source heatpumps but I don't think it's usually necessary here. Go some 500km North (google "Oulu climate") and things get very different. Yet people do install air source heat pumps even there and with a well adjusted system, are able to reach and exceed Seasonal COP of 2. Cost of heating oil and electricity is now basically 1:1 per energy here, so such 2x energy saving pays back.
For example, my heat pump, a modern quite well designed but still a cheap Chinese unit kind-of-but-not-quite designed for Nordic climate, reaches COP1 at dT=80 degC, i.e., at ambient -25degC water +55degC. Obviously at that point it's wiser to turn the compressor off and run resistive elements, because such usage is also hardest on the compressor, eating more of its life hours.
The change has to be done somewhat earlier from simply the power sufficiency viewpoint. My 9kW nominal machine supplies 4kW at -15degC out / 45degC water, and it also happens my home requires just this, 4kW at -15degC. Below that temperature, resistive support heating would be needed, unless I bought a larger heat pump, but that would be an expensive extra investments just to get slightly higher COP for a few weeks per year. Combining 4kW at COP1.84 and 1kW resistive aux power at COP1 is COP1.58.
But yeah, 3x price difference between electric energy and burnable thermal energy (gas, coal, oil, wood, whatever) pretty much negates the whole point of getting a heatpump. But this is a (stupid) political/business decision; I believe - or hope - it's going to change. If the aim is to Save The World by reducing CO2 and burn less fossils, burning all the same fossils in modern power plants to run distributed heat pumps at households is already a massive improvement; adding renewables such as wind, solar, hydro on top only helps.
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The problem with heat pumps is that they are effectively pumping heat "uphill" and the colder it is outside, the taller the hill is.
Right. That's why for heatpump systems heated floors are better choice compared to radiators.
And one winter we had an unusually cold week where the heat pump was completely useless because the outside temperature was too cold.
Even scarier story - when for some reason many neighbor houses have heat pumps, you all may get grid overload brownouts during extreme cold.
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The sufficiency of grid - or actually production, as the grid itself is very good here - is being discussed here in the heat pump circles because the government is subsidising air-to-water heat pumps with the condition that the oil burner must go. This is totally nuts because even if the oil burner was left as a backup, the heat pump would reduce the oil consumption by some 10x on average, the CO2 emission of that is totally negligible. Even in Southern Finland where most of the population is, it's possible to have several weeks of -25 degC straight although that doesn't happen every winter or even every decade. This means that save for a few in-floor heating houses with carefully tuned flagship heatpumps, most of those "converted" oil houses are running direct resistive electric heating, consuming nearly 10kW per household on average for heating, when they used to consume 50W for the oil burner. At the same time, electricity is needed everywhere else. Last winter, backup fossil plants were already needed (although it was officially "just testing" but somehow happened exactly when the demand exceeded production by 2GW) and we were totally on the mercy of the kind Swedish who had their near-collapse as well and still delivered us power all the time. (We are nowadays continuously importing from all our neighbors. It didn't use to be that way.)
Heat distribution system makes a huge difference. Heat pump is interested about the delta between the outside air, and heating water. If +60degC water is already needed at mere -10degC, that's already the final limit when the pump's definitely out, and COP is crap even before that. But a well designed in-floor heating might be happy running +30degC water even at -30degC out, that's quite an achievement for a heat pump.
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Perhaps instead of banning oil or gas heat, just require it to be CHP? It would complement solar very well in that it would be used the most when solar is generating the least and vice versa.
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Perhaps instead of banning oil or gas heat, just require it to be CHP? It would complement solar very well in that it would be used the most when solar is generating the least and vice versa.
Or apply the true external cost of oil or gas fuel instead of ignoring economics:
https://en.wikipedia.org/wiki/Pigovian_tax
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Taxation in Finland is a nightmare (basically everything has "pigovian" tax on top of every other tax), but one thing has worked out as it should, IMHO, and has been that way for a long time: electric power has low pigovian tax, and fossil fuels have significantly higher taxes, resulting in approximate energy price parity between oil : electricity. This means it's roughly 4x cheaper to run an EV (that runs at 80% efficiency instead of 20%), or approximately 3x cheaper to run a heat pump with SCOP=3.
And having 1:1 energy price parity isn't excessively unfair for those who need or want to use oil. It sounds fair to me, you pay the same for the energy you use. In many countries it's super cheap to burn fossils to the point that converting into 3x less energy usage by 3x more efficient equipment is not financially viable. This is almost funny because we here run air source heatpumps, in climate where their operation is marginal, and where they would work really well they are not used because of politics.
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In many countries it's super cheap to burn fossils to the point that converting into 3x less energy usage by 3x more efficient equipment is not financially viable.
Certainly in the UK a COP of around 3 is near the break even point. Add in a history of very simple, low-cost gas boilers with a public perception of reliability, and the fact that various green subsidies are added to electricity costs and not to gas (a political problem) and we end up where we are now - the general public does not want heat pumps even with heavily subsidised install costs.
Gas prices are very much on their way up though, which may change things.
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Subsidizing the install cost is exactly the wrong way to do it. Here subsidising the already excessive 8000EUR investment by 4000EUR caused the price to jump to some 14000EUR, increasing the leftover investment and making it financially unviable.
Because the thing really saves energy, a lot of energy, and energy cost is significant, the only right thing to do is to treat different forms of energy equally (or based on their harmfulness, so on that logic you could make electricity a tad cheaper than fossils because there are at least some renewables in the mix). But now in many European countries, UK included, it seems to be the opposite, fossils are cheap compared to electric energy so people do not want EVs or heatpumps, they don't save enough to break even.
But this isn't getting any better, shortage of electric power is driving prices even higher and people burn fossils in a distributed way, with very poor total efficiency such as 15-70%, when 70-250% would be easily achievable (for transportation and heating, respectively)
In this situation, even building more modern combined cycle facilities and start burning fossils there, to push down the price of electricity, would be an improvement regarding total CO2 produced!
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Heat distribution system makes a huge difference. Heat pump is interested about the delta between the outside air, and heating water. If +60degC water is already needed at mere -10degC, that's already the final limit when the pump's definitely out, and COP is crap even before that. But a well designed in-floor heating might be happy running +30degC water even at -30degC out, that's quite an achievement for a heat pump.
Ignoring boutique overhead, ceiling heating might be interesting. Easy to retrofit in combination with a tensioned ceiling.
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Yes, it all comes back to maximizing surface area to provide the necessary heating power with lower temperature. Floor and ceiling are equal here, but floor has additional benefit that you can drop the room temperature by a degree or two as your feet will stay warm.
Installing heating pipes to floor, ceiling and walls with 100% coverage would result in flat line as the heating curve so that water temperature would always equal to the desired room temperature. Would be one heck of a heatpump COP beast. (Not practical, just the idea for reference.) Forced air convectors (fan units) come pretty close, and also for that reason simple air-to-air heatpumps are very efficient and for little cost. It's just inconvenient to install one to every room or so. A friend of mine has five in his house, and likely is considering adding at least one more. I ended up just installing the air-to-water unit even though it's a clear loss of COP in a radiator house. But you get the heat everywhere.
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Yes, it all comes back to maximizing surface area to provide the necessary heating power with lower temperature. Floor and ceiling are equal here, but floor has additional benefit that you can drop the room temperature by a degree or two as your feet will stay warm.
Installing heating pipes to floor, ceiling and walls with 100% coverage would result in flat line as the heating curve so that water temperature would always equal to the desired room temperature. Would be one heck of a heatpump COP beast. (Not practical, just the idea for reference.) Forced air convectors (fan units) come pretty close, and also for that reason simple air-to-air heatpumps are very efficient and for little cost. It's just inconvenient to install one to every room or so. A friend of mine has five in his house, and likely is considering adding at least one more. I ended up just installing the air-to-water unit even though it's a clear loss of COP in a radiator house. But you get the heat everywhere.
there is an office building a few years old here, that as I understand it it uses a heat pump sourced from circulating groundwater from a well to do both heating and cooling with water circulating in walls and floor
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Taxation in Finland is a nightmare (basically everything has "pigovian" tax on top of every other tax), but one thing has worked out as it should, IMHO, and has been that way for a long time: electric power has low pigovian tax, and fossil fuels have significantly higher taxes, resulting in approximate energy price parity between oil : electricity. This means it's roughly 4x cheaper to run an EV (that runs at 80% efficiency instead of 20%), or approximately 3x cheaper to run a heat pump with SCOP=3.
The usual problem with taxes is that special interests get exceptions written into the law which defeats the purpose of a Pigovian tax. At least that is how it works in the US.
If you are going to apply a Pigovian tax of emissions, or specifically CO2, to fossil fuels then it needs to be applied per mole of carbon, without any exceptions or subsidies at all. It should be easy to administer because almost all fuel travels through a limited number of points in bulk. Of course if the fuel is not burned, then somehow that has to be accounted for, because some fossil fuels are used for other processes where the carbon will not be released.
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In areas that regularly go below freezing, could a heat pump be developed that freezes water to make ice and then throw the ice outside?
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In areas that regularly go below freezing, could a heat pump be developed that freezes water to make ice and then throw the ice outside?
Sure, but that assumes a source of liquid water, and having to melt water for the heat pump to freeze would defeat the purpose.
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Well most areas are going to have liquid tap water, but consider this. In this part of the world heat pump system capacity is measured in tons, for a a modest house 2-3.5 tons is typical. That is tons of ice that can be melted or frozen in a 24 hour period, so if you have a house like mine with a 3 ton heat pump you could conceivably be looking for somewhere to stack thousands of pounds of ice per day.
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In areas that regularly go below freezing, could a heat pump be developed that freezes water to make ice and then throw the ice outside?
The energy needs to come from somewhere -> you need source of water -> that source of water is providing the energy -> energy is actually coming from ground -> this already exists, is called "ground source heat pump". langwadt described this above, some literally circulate ground water and cool it down by a few degrees (there's no need to go as far as freezing it and throwing it out). Others just cool down the bedrock, or soil, for example by drilling a deep well. This is more efficient than air source because the ground source is always at approx. +5 degC even in the coldest climates, but the investment cost is usually pretty high because surface area needs to be high, necessitating deep holes (like 200 meters).
For your idea about ice, air source heat pumps are already condensing water from the cold (nearly RH=100%) outdoor air, which gives energy. But then the ice starts blocking the evaporator coil, and defrosting cycle melts that ice, losing the gained energy. Some industrial grade air source heat pumps, AFAIK, use very sparse evaporator coil fins, in a horizontal installation so that the defrosting cycle actually sheds/drops a significant part of the ice, as ice. This obviously improves the efficiency by utilizing the energy gained making that ice in the first place, and only wasting small part of it during defrosting. But this is just a minor optimization, maybe it gives you 0.1 to 0.2 units of COP.
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Do you mean like in Iceland, where nearby volcanoes have heated the earth up hot enough to heat groundwater and spring water toasty warm?
Mmmm! Sounds nice. Just hope it doesn't erupt and cause a nuclear winter. Then the bills will really soar.
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Well most areas are going to have liquid tap water, but consider this. In this part of the world heat pump system capacity is measured in tons, for a a modest house 2-3.5 tons is typical. That is tons of ice that can be melted or frozen in a 24 hour period, so if you have a house like mine with a 3 ton heat pump you could conceivably be looking for somewhere to stack thousands of pounds of ice per day.
Where does the energy to run that pump come from, natural gas, electricity, oil?
Hopefully not solar roadways..
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Heat distribution system makes a huge difference. Heat pump is interested about the delta between the outside air, and heating water. If +60degC water is already needed at mere -10degC, that's already the final limit when the pump's definitely out, and COP is crap even before that. But a well designed in-floor heating might be happy running +30degC water even at -30degC out, that's quite an achievement for a heat pump.
Ignoring boutique overhead, ceiling heating might be interesting. Easy to retrofit in combination with a tensioned ceiling.
Heat builds up near the ceiling in a conventinally heated room and a small fan placed near the ceiling blowing the warmer air downward mixes the air and reduces heating costs. I used to have one like this, a small vertical fan hung from a piece of wire did the job well. This was back when energy was cheaper than today. So I'd imagine the savings might be more now.
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Where does the energy to run that pump come from, natural gas, electricity, oil?
Hopefully not solar roadways..
It comes from electricity, which in my region is from a mix of sources, about 60% hydro.
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So, it uses electricity which around here ALREADY costs at least 3 times as much as gas... probably more.
This is smoke and mirrors..
The problem with heat pumps is that they are effectively pumping heat "uphill" and the colder it is outside, the taller the hill is.
Right. That's why for heatpump systems heated floors are better choice compared to radiators.
And one winter we had an unusually cold week where the heat pump was completely useless because the outside temperature was too cold.
Even scarier story - when for some reason many neighbor houses have heat pumps, you all may get grid overload brownouts during extreme cold.
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So, it uses electricity which around here ALREADY costs at least 3 times as much as gas... probably more.
This is smoke and mirrors..
Well duh it uses electricity, how else are you going to drive a refrigeration compressor?
It isn't smoke and mirrors, it's still marginally cheaper than natural gas in this area. I like having multiple fuel sources, I can choose whether to run the heat pump or gas furnace depending on ambient conditions and energy prices. They are predicting big jumps in natural gas prices so if that happens I'll use the heat pump more.
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So, it uses electricity which around here ALREADY costs at least 3 times as much as gas... probably more.
The product is not smoke and mirrors, instead your local market structures and/or politics have made a decision, implicit or explicit, to basically support distributed burning of fossil fuels by offering them 3x cheaper per energy, than greener electric power. Go figure. Ignore all nice talk about green values, this is the harsh reality.
Obviously, if you decide by economics, as most of us do because we don't have unlimited money at our disposal, and don't want to move somewhere else*, then by all means do not invest into a heatpump. It won't make financial sense to you. So keep spewing 3-10x more CO2 and thousands of times more cancerous particulates by burning fossils. Keep using the same amount of energy that could heat three houses, just to heat yours. I don't want to be a hypocrite, so I admit I'd likely do same, it's about your hard earned money after all.
*) I don't recommend coming here even though I think the taxation of fossil fuels and the cost of electric energy are fair but that's one of the few bright sides.
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Do you mean like in Iceland, where nearby volcanoes have heated the earth up hot enough to heat groundwater and spring water toasty warm?
That's one thing, it's like the very real geothermal i.e., utilizing heat from the core of Earth. If you have such source of energy, you may not need a heatpump at all, just circulation pump and heat exchangers work.
But usually, "ground source heat pump" does mean a mix of a tiny bit of Earth core heat, but mostly solar heat stored by the massive amount of bedrock/soil around the year. These pumps do not require active volcanoes but work anywhere. You just drill some 200m (700 feet) hole to extract the energy. The temperature in that hole follows the yearly average of that climate pretty well. It heats up maybe a degree or two in summer, and cools down maybe a degree or two during winter. Pretty steady heat source. By pumping from say +5 to +35, COP is easily like 5. Great for heating in cold climates. Yes, it uses electricity too but not much. Instead of drilling a hole, if you have a lake or a river which does not freeze during winter, ground source heat pump can extract energy from that. Much cheaper to install.
But not worth the investment either if burning fossils is indirectly subsidized by 300%.
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No need for hyperbole here. Burning natural gas does emit CO2 but there is very little in the way of particulates. I recently cleaned the outside of the vent on my furnace and after 16 years the inside of the white plastic flue pipe looks squeaky clean, there is not a trace of soot. In a properly working appliance it is a very clean burning fuel.
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It might also be slightly interesting to note that the UK government has recently been encouraging electricity producers to burn more gas due to an industrial shortage of CO2, leading to supply chain problems with food and other products. Apparently, CO2 is an important industrial commodity, and it is usually produced by recovering it from the burning of fossil fuels. If electricity becomes 100% renewable, then CO2 has to be made by other means.
In the same way that ecological systems are often finely balanced, so are industrial systems. Disturb one part of the system and the whole thing can be affected in ways you didn't bargain for.
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Apparently, CO2 is an important industrial commodity, and it is usually produced by recovering it from the burning of fossil fuels.
But not for electricity generation,our shortage was cause by 2 fertilizer manufacturers closing down due to the cost of gas,something like 60% of our co2 is produced this way.
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Seems odd that they would produce CO2 rather than just recover it from the air. With talk of trying to capture and store CO2 to keep it out of the atmosphere it makes no sense not to deliver it to industrial users before worrying about trying to store it. Many industrial gases are obtained by distillation of liquefied air.
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But not for electricity generation,our shortage was cause by 2 fertilizer manufacturers closing down due to the cost of gas, something like 60% of our co2 is produced this way.
OK, that's logical, it didn't occur to me to think of it that way. Fertilizer plants produce huge amounts of CO2 as a by-product. With the decline in the UK industrial base, and my long absence from the country, I didn't even know we had any fertilizer plants left in operation.
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Even scarier story - when for some reason many neighbor houses have heat pumps, you all may get grid overload brownouts during extreme cold.
That brings up another problem. If I want to be prepared for a power outage, powering a gas furnace with a backup generator is much easier than powering a heat pump.
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That brings up another problem. If I want to be prepared for a power outage, powering a gas furnace with a backup generator is much easier than powering a heat pump.
I mentioned that earlier. I run my gas furnace easily from my 2kW Honda inverter generator which is 120V only. My heat pump draws around 3kW and requires 240V so to run that I'd need a much larger generator. Dual fuel is the best of both worlds IMO although it's expensive if you buy new equipment and pay someone to install it. I pieced mine together out of scratch & dent stuff I picked up for a song.
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It's only 0.04% of air, and it's not liquid at ambient pressure, so it's hard to extract.
Seems like there must be a lot of it somewhere if CO2 emissions are as big a problem as people say. They get argon and neon and other rare gasses from the air, pretty sure they extract oxygen from air too. I never put a lot of thought into how other gasses are obtained but I've read about proposed schemes to pull CO2 out of the air and store it.
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Perhaps if they required all new gas heat to be CHP it can greatly enhance the resiliency of the grid during the winter.
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Seems like there must be a lot of it somewhere if CO2 emissions are as big a problem as people say. They get argon and neon and other rare gasses from the air, pretty sure they extract oxygen from air too. I never put a lot of thought into how other gasses are obtained but I've read about proposed schemes to pull CO2 out of the air and store it.
There's a "lot" of CO2 in the atmosphere as far as the greenhouse effect is concerned, but it is not a lot in terms of the concentration required to make it viable to recover in the quantities required by industry. Argon and neon also occur in the atmosphere in small concentrations, but they are much more valuable and are needed in smaller quantities.
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Burning the very same natural gas in a combined cycle facility makes a lot of sense because now you can extract the CO2 for industrial needs, can't do that in distributed burning.
1kWh of natural gas when burned in a facility:
* No CO, particulates or whatever because the process is in control,
* CO2 for the industry, whenever needed,
* Approx. 0.55kWh of electricity, which becomes 0.5kWh after grid distribution loss, which becomes at very least 1.5kWh of heat in air-source heatpump
* Approx. 0.20kWh of district heating
Sum of heat production alone is 1.7kWh for 1kWh of natural gas (170% "efficiency") and it's more flexible because the electricity can be used for other purposes than heating.
Same 1kWh of natural gas, when locally burned for heating, offers some 0.9kWh of heat (90% "efficiency"), although I do admit that my comment on particulates earlier is kind of hyperbole because the process usually is good enough even at home. I was thinking about oil where particulates are bigger problem if the process isn't spot-on.
The obvious advantage of the electricity-based heating energy distribution is that this 170% fossil efficiency is the baseline starting point. No grid is 100% fossil-based. Add renewable energy into the mix and it only gets better, sometimes significantly, depending on where you live and whether you consider nuclear "green" or not (I'm not commenting on that because it doesn't need to be discussed here, it isn't relevant enough).
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There's a "lot" of CO2 in the atmosphere as far as the greenhouse effect is concerned, but it is not a lot in terms of the concentration required to make it viable to recover in the quantities required by industry. Argon and neon also occur in the atmosphere in small concentrations, but they are much more valuable and are needed in smaller quantities.
Argon and neon are produced as byproducts of liquefying nitrogen and oxygen from the atmosphere:
https://en.wikipedia.org/wiki/Argon#Production
https://en.wikipedia.org/wiki/Neon#Occurrence
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There's a "lot" of CO2 in the atmosphere as far as the greenhouse effect is concerned, but it is not a lot in terms of the concentration required to make it viable to recover in the quantities required by industry. Argon and neon also occur in the atmosphere in small concentrations, but they are much more valuable and are needed in smaller quantities.
Argon and neon are produced as byproducts of liquefying nitrogen and oxygen from the atmosphere:
https://en.wikipedia.org/wiki/Argon#Production
https://en.wikipedia.org/wiki/Neon#Occurrence
I had just assumed that CO2 was produced the same way, apparently not, at least not in large quantities. The talk I've seen of storing CO2 pulled from the environment seem to focus on the storage aspect when it seems the focus really ought to be on the capturing aspect because if we can't pull enough of it out of the air to meet industrial needs then there is no point in trying to store it. I had always assumed that using CO2 was a zero sum game since I figured it was pulled out of the air to be put in tanks and eventually let back out into the air.
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There is no economic incentive for large scale CO2 capture from air or powerplants, if Western states truly commit to it it can likely get done. The economics for it can just be created up to a point. That they aren't there now proves only that with the current cost model it's not the cheapest, cost models can be changed.
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It may be more cost effective to improve the insulation of your house, including properly sealing any leaks around doors and windows.
You can do that only up to a certain extend. At some point lack of ventilation will cause moisture to build up which in turn is an excellent breeding condition for mold. With insulation you also need to add ventilation.
Using an AC system to heat is also an option. Earlier this year I installed a new AC system which can both cool and heat.
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CO2 tends to be captured from power plant flue gases as a result of legislation rather than economics (it is very expensive to do). The CO2 when captured is rarely used for any purpose--the main goal is to sequester it so it doesn't get back into the atmosphere.
CO2 is produced by fertilizer plants as a byproduct of making hydrogen from natural gas* (methane, CH4). After you have removed the hydrogen from the CH4 molecule, you have a bunch of carbon left over, which ends up as a nearly pure stream of CO2 that you have to dispose of somehow. Since it is already nearly pure, and is available for free, it is a much more economic source of CO2 then trying to extract it from other sources.
* Steam reforming of methane. Roughly speaking, CH4 + 2 H2O => 4 H2 + CO2
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Using an AC system to heat is also an option. Earlier this year I installed a new AC system which can both cool and heat.
That's called a heat pump, and has been discussed extensively further up in this same thread.
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CO2 tends to be captured from power plant flue gases as a result of legislation rather than economics (it is very expensive to do). The CO2 when captured is rarely used for any purpose--the main goal is to sequester it so it doesn't get back into the atmosphere.
That illustrates the ridiculous outcomes of a lot of well meaning legislation. It makes absolutely zero sense to capture CO2 and not use it for anything in order to keep it out of the environment while purposely generating CO2 elsewhere for use. If one recognizes that CO2 is going to be used for many purposes, it makes sense to make full use of any that is captured.
It also seems silly to use natural gas to make hydrogen when it can be made from electricity and the plants producing it for industrial use can be conveniently located near cheap electricity.
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It also seems silly to use natural gas to make hydrogen when it can be made from electricity and the plants producing it for industrial use can be conveniently located near cheap electricity.
This is the direction the world is going, but it will take time for everything to shift over.
Although hydrogen "can" be made from electricity, it is currently very slow and very expensive to do so, especially in the quantities required industrially. It only makes sense to do so when the electricity comes from renewable sources. Otherwise, you replace a process that goes (natural gas) => (hydrogen) with a process that goes (natural gas) => (electricity) => (hydrogen).
Also, bear in mind that the plants producing the hydrogen for industrial use need to be located near the place where the hydrogen is needed, which is not necessarily near to cheap electricity. It is very difficult to transport hydrogen around (another reason why the "hydrogen economy" is not going to happen overnight).
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It is very difficult to transport hydrogen around (another reason why the "hydrogen economy" is not going to happen overnight).
Natural gas is already widely shipped and used (for trucks) as a cryogenic liquid. It will make it more expensive still, but easier to transport by tanker.
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It may be more cost effective to improve the insulation of your house, including properly sealing any leaks around doors and windows.
You can do that only up to a certain extend. At some point lack of ventilation will cause moisture to build up which in turn is an excellent breeding condition for mold. With insulation you also need to add ventilation.
This is a horribly outdated way of thinking. And it's also outright wrong; air leaks through structures are possibly #1 reason for hidden mold problems. It's absurd to think fixing leaks causes the problem, it's exactly the opposite.
You need ventilation regardless of insulation. Do not ventilate through insulation or structures!
You may think it's only air coming in through the leak, but in certain conditions, air is going out through that gap, too. And the absolute humidity (dew point) of indoor air is usually higher than outdoors - condensation happens when the leaking warm, absolutely humid air cools down in that gap. Mold grows somewhere in that structure, invisible to anyone. Then you get your "ventilation" through that moldy gap.
Also if air flows through insulating wools, their thermal resistance goes down.
Ergo, ventilation should never provided through random air leaks. Ventilation should be provided, at very least, through dedicated openings/valves. Fixing leaks and adding dedicated openings is one of the first and most obvious renovations to do in an old house. It's also a simple low cost operation. Do it. There is no reason not to; you just change the air flow to happen through better routes, enabling more clean, less moldy air, eliminate further mold growth risks. Energy-wise, there usually is not much difference assuming you don't increase the amount of ventilation.
Then comes the question of energy recovery. This becomes important only after the insulation is good enough so that energy lost through ventilation becomes significant part of total cost.
Having separate incoming/outgoing ducting enables easy addition of heat recovery unit but such ducting is tedious to retrofit if the dual ducting doesn't exist at the build time.
Having existing "exhaust only" fan in a single point (with single ducting) enables easy addition of exhaust air heat pump for energy recovery.
In case the house is built with no attention for ventilation at all, single-room heat recovery ventilators like the Mitsubishi Lossnay VL-50 (which I have installed in our bedroom) are easy to retrofit.
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It is very difficult to transport hydrogen around (another reason why the "hydrogen economy" is not going to happen overnight).
Natural gas is already widely shipped and used (for trucks) as a cryogenic liquid. It will make it more expensive still, but easier to transport by tanker.
It will be much more expensive due to technical challenges. For instance first hydrogen transport 116m ship (https://newatlas.com/marine/kawasaki-worlds-first-liquid-hydrogen-transport-ship/) will have just 1250 m3 capacity. Excerpt from article:
The hydrogen will be compressed to 1/800 of its regular gaseous volume, and cooled to -253° C (-423.4° F) in order to stop it from seeping out through the tank walls due to the sheer tininess of the hydrogen molecules, which can literally seep through the gaps in the atomic structure of a metal container at higher temperatures.
Said project essentially is test of "pollution export" - Australia will get 100 tonnes of co2 pollution for Japan to get 3 tonnes of hydrogen. So, yes - hydrogen is "dirty fuel", unless manufactured from renewable energy sources.
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Do you mean like in Iceland, where nearby volcanoes have heated the earth up hot enough to heat groundwater and spring water toasty warm?
That's one thing, it's like the very real geothermal i.e., utilizing heat from the core of Earth. If you have such source of energy, you may not need a heatpump at all, just circulation pump and heat exchangers work.
But usually, "ground source heat pump" does mean a mix of a tiny bit of Earth core heat, but mostly solar heat stored by the massive amount of bedrock/soil around the year. These pumps do not require active volcanoes but work anywhere. You just drill some 200m (700 feet) hole to extract the energy. The temperature in that hole follows the yearly average of that climate pretty well. It heats up maybe a degree or two in summer, and cools down maybe a degree or two during winter. Pretty steady heat source. By pumping from say +5 to +35, COP is easily like 5. Great for heating in cold climates. Yes, it uses electricity too but not much. Instead of drilling a hole, if you have a lake or a river which does not freeze during winter, ground source heat pump can extract energy from that. Much cheaper to install.
But not worth the investment either if burning fossils is indirectly subsidized by 300%.
here most geothermal is not vertical, it is horizontal over a larger area either plowed or digged down to ~1m
I've heard some use a well and circulate ground water, but there is probably lots of regulations because potentially
pumping stuff into the ground water would be bad
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here most geothermal is not vertical, it is horizontal over a larger area either plowed or digged down to ~1m
I've heard some use a well and circulate ground water, but there is probably lots of regulations because potentially
pumping stuff into the ground water would be bad
Yeah, depends on the soil. Horizontal is great in clay soil. Vertical is the way to go when you are directly on the top of bedrock; thermal conductivity of rock is OK for heat pumping, but it's impractical to drill in any other direction than down. AFAIK, sand is not the greatest soil type for ground source.
At least here, all modern (or at least legal) ground source systems use ethanol-water mix instead of glycol so that the leak does not pollute ground water. Not even propylen glycol is allowed. Another, possibly the actual reason for using ethanol is lower viscosity because pumping losses in such long piping (possibly in excess of a kilometer!) are significant.
Nowadays it's sometimes hard to get permission to build ground source systems here especially in the presence of ground water but I think it's more about politics than any actual reasoning. I.e., ground source companies have not invested in lobbying hard enough, which is what you need to do if you want to run any business in the Not-Allowed-Land.
Having a river or a big lake nearby is really the most optimal case for low-cost high-efficiency ground source heat pumping but few have that luxury available.
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I had just assumed that CO2 was produced the same way, apparently not, at least not in large quantities. The talk I've seen of storing CO2 pulled from the environment seem to focus on the storage aspect when it seems the focus really ought to be on the capturing aspect because if we can't pull enough of it out of the air to meet industrial needs then there is no point in trying to store it. I had always assumed that using CO2 was a zero sum game since I figured it was pulled out of the air to be put in tanks and eventually let back out into the air.
I thought the same thing for a long time, but as IanB points out, CO2 is a massive byproduct of hydrogen production from methane for production of fertilizer and petrochemicals, so that is the largest source.
It also seems silly to use natural gas to make hydrogen when it can be made from electricity and the plants producing it for industrial use can be conveniently located near cheap electricity.
It just comes down to economics. The electricity needed to produce enough hydrogen for ammonia (fertilizer) production would be massive, and unless you want to burn fossil fuel to supply it, is really only practical with nuclear power.
If nuclear power is acceptable, then there are better ways like high temperature electrolysis of water, or the surfer-iodine cycle (https://en.wikipedia.org/wiki/Sulfur%E2%80%93iodine_cycle).
Of course politics trumps economics all the time, except when it does not, and ultimately it never does. But that is what we are discussing.
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I had always assumed that using CO2 was a zero sum game since I figured it was pulled out of the air to be put in tanks and eventually let back out into the air.
Not a zero sum game at all, hence all the fuss about climate change. Lots of carbon is bound up in fossil fuels like coal, oil and gas, where it is safely out of the way and not contributing to the greenhouse effect. But over the years, with the burning of these fuels, lots of carbon is being put into the atmosphere as CO2, which is a problem. It is not possible to get the CO2 back out of the atmosphere once it has been released, but it is possible to stop adding to the problem. Hence the need to switch to renewable energy sources, and to capture CO2 from the burning of fossil fuels and prevent its release.
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Not a zero sum game at all, hence all the fuss about climate change. Lots of carbon is bound up in fossil fuels like coal, oil and gas, where it is safely out of the way and not contributing to the greenhouse effect. But over the years, with the burning of these fuels, lots of carbon is being put into the atmosphere as CO2, which is a problem. It is not possible to get the CO2 back out of the atmosphere once it has been released, but it is possible to stop adding to the problem. Hence the need to switch to renewable energy sources, and to capture CO2 from the burning of fossil fuels and prevent its release.
I'm not talking about CO2 resulting from burning stuff, I'm talking about the vast quantities of CO2 that are used for industrial purposes. Even just what is used in soft drinks must be non-trivial when looking globally.
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It will be much more expensive due to technical challenges. For instance first hydrogen transport 116m ship (https://newatlas.com/marine/kawasaki-worlds-first-liquid-hydrogen-transport-ship/) will have just 1250 m3 capacity. Excerpt from article:
The first pilot ship is small and expensive? You don't say. The trucking industry is already making liquid hydrogen fuel tanks, huge amounts of practical development going on there with relatively little subsidy. Liquid hydrogen is piggy-backing on experience from LNG.
Trucking much like seasonal storage is where the rock meets the hard place ... liquid hydrogen is expensive, fine. Present a cheaper alternative ready to provide decarbonization in three decades. Nuclear is tentatively cheaper than seasonal storage with renewable, but for trucking you need power to liquid of some form and hydrogen has the greatest technical readiness. The promises from governments currently require hydrogen, it's that simple. Expensive can be done, fairy tales don't solve shit.