Author Topic: More or Most efficient hydronic heating basic unit? (natural gas)  (Read 5639 times)

0 Members and 1 Guest are viewing this topic.

Offline cdev

  • Super Contributor
  • ***
  • Posts: 6627
  • Country: 00
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.
« Last Edit: October 23, 2021, 05:01:07 pm by cdev »
"What the large print giveth, the small print taketh away."
 

Online langwadt

  • Super Contributor
  • ***
  • Posts: 2821
  • Country: dk
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #1 on: October 23, 2021, 03:21:21 pm »
60% sounds low unless it is ancient, look up what it actually is. Modern condensing boilers are close to 100%
 

Offline Nauris

  • Regular Contributor
  • *
  • Posts: 186
  • Country: fi
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #2 on: October 23, 2021, 03:23:56 pm »
Have you considered air to water heat pump? Thats what everybody here seems to be replacing expensive oil heating with.
 

Offline cdev

  • Super Contributor
  • ***
  • Posts: 6627
  • Country: 00
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #3 on: October 23, 2021, 03:43:34 pm »
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.
« Last Edit: October 23, 2021, 05:37:38 pm by cdev »
"What the large print giveth, the small print taketh away."
 

Offline cdev

  • Super Contributor
  • ***
  • Posts: 6627
  • Country: 00
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #4 on: October 23, 2021, 05:08:31 pm »
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.

« Last Edit: October 23, 2021, 05:32:00 pm by cdev »
"What the large print giveth, the small print taketh away."
 

Online jpanhalt

  • Super Contributor
  • ***
  • Posts: 1454
  • Country: us
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #5 on: October 23, 2021, 06:05:54 pm »
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.
 

Offline IanB

  • Super Contributor
  • ***
  • Posts: 10373
  • Country: us
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #6 on: October 23, 2021, 06:18:25 pm »
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.
I'm a ChemE--I know all about the flow of fluids.
 

Offline WattsThat

  • Frequent Contributor
  • **
  • Posts: 607
  • Country: us
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #7 on: October 23, 2021, 06:19:32 pm »
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.
 
 

Offline Nauris

  • Regular Contributor
  • *
  • Posts: 186
  • Country: fi
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #8 on: October 23, 2021, 07:03:04 pm »
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.
« Last Edit: October 23, 2021, 08:01:24 pm by Nauris »
 

Offline PaulAm

  • Frequent Contributor
  • **
  • Posts: 837
  • Country: us
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #9 on: October 23, 2021, 07:24:48 pm »
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.
 

Online langwadt

  • Super Contributor
  • ***
  • Posts: 2821
  • Country: dk
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #10 on: October 23, 2021, 09:13:00 pm »
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


 

Offline james_s

  • Super Contributor
  • ***
  • Posts: 16935
  • Country: us
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #11 on: October 23, 2021, 11:27:20 pm »
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.
 
The following users thanked this post: edavid

Offline james_s

  • Super Contributor
  • ***
  • Posts: 16935
  • Country: us
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #12 on: October 23, 2021, 11:32:54 pm »
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.
« Last Edit: October 23, 2021, 11:35:19 pm by james_s »
 

Offline cdev

  • Super Contributor
  • ***
  • Posts: 6627
  • Country: 00
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #13 on: October 24, 2021, 02:04:46 am »
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.
"What the large print giveth, the small print taketh away."
 

Online Marco

  • Super Contributor
  • ***
  • Posts: 5366
  • Country: nl
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #14 on: October 24, 2021, 02:05:44 am »
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.
« Last Edit: October 24, 2021, 02:10:30 am by Marco »
 

Offline David Hess

  • Super Contributor
  • ***
  • Posts: 14088
  • Country: us
  • DavidH
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #15 on: October 24, 2021, 02:42:52 am »
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.
 

Offline Siwastaja

  • Super Contributor
  • ***
  • Posts: 4853
  • Country: fi
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #16 on: October 24, 2021, 10:08:35 am »
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.
« Last Edit: October 24, 2021, 11:34:02 am by Siwastaja »
 

Offline NiHaoMike

  • Super Contributor
  • ***
  • Posts: 7735
  • Country: us
  • "Don't turn it on - Take it apart!"
    • Facebook Page
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #17 on: October 24, 2021, 01:32:34 pm »
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?
Cryptocurrency has taught me to love math and at the same time be baffled by it.

Cryptocurrency lesson 0: Altcoins and Bitcoin are not the same thing.
 

Offline Siwastaja

  • Super Contributor
  • ***
  • Posts: 4853
  • Country: fi
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #18 on: October 24, 2021, 01:37:14 pm »
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.
« Last Edit: October 24, 2021, 01:46:03 pm by Siwastaja »
 

Offline cdev

  • Super Contributor
  • ***
  • Posts: 6627
  • Country: 00
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #19 on: October 24, 2021, 03:14:07 pm »
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.
« Last Edit: October 24, 2021, 04:45:03 pm by cdev »
"What the large print giveth, the small print taketh away."
 

Online langwadt

  • Super Contributor
  • ***
  • Posts: 2821
  • Country: dk
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #20 on: October 24, 2021, 04:21:21 pm »
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 following users thanked this post: cdev, Siwastaja

Offline Siwastaja

  • Super Contributor
  • ***
  • Posts: 4853
  • Country: fi
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #21 on: October 24, 2021, 04:24:35 pm »
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?
« Last Edit: October 24, 2021, 04:31:24 pm by Siwastaja »
 

Offline cdev

  • Super Contributor
  • ***
  • Posts: 6627
  • Country: 00
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #22 on: October 24, 2021, 04:48:37 pm »
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?
"What the large print giveth, the small print taketh away."
 

Offline Siwastaja

  • Super Contributor
  • ***
  • Posts: 4853
  • Country: fi
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #23 on: October 24, 2021, 04:54:57 pm »
... 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.
 

Online langwadt

  • Super Contributor
  • ***
  • Posts: 2821
  • Country: dk
Re: More or Most efficient hydronic heating basic unit? (natural gas)
« Reply #24 on: October 24, 2021, 05:01:59 pm »
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
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf