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Offline george80

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Winter heating and power generation ideas.
« on: February 16, 2019, 02:46:00 pm »

Winter is coming  here in oz and no doubt where I am the 40oC temps will soon be replaced by 4oC

I'm thinking / planning a few options for heating and power generation and would like to get some feedback on things I may not have thought of and maybe give others some ideas as well.

My home is 20 Yo and all electric. The insulation is not bad but due to the style of the house, there are a LOT of windows and Doors. Something like 16 SETS of windows ( all being 2-3 pane/ openings) and 7 Doors, 5 of them doubles and at least half glass.  Not great for insulation. No gas in the area, no wood heating etc. All out heating and cooling is from a big 3 phase AC unit.

 I have 20Kw of solar on the roof and adding a bit more but it's a case of very diminishing returns.  I have about 10KW on the optimal north side and the rest is on the west and a bit on the south. While the south is the complete " wrong" side, because that is on the shed with only a 5o Tilt ( 34 optimal here) it actually produces pretty good power. The panels were only leftovers I had anyway so put them up to make some use of them and have been surprised how well they do..... in summer at least.  Winter is pretty useless but then again the west ones fall off badly in winter too but crack along in summer.

The problem with more panels is I only need the power in winter where the solar radiation falls through the floor. In summer  I have been running about half my present capacity and making more power than I know what to do with literally and don't get anything for feedback. In winter I can't make enough and one of my smaller arrays in summer will make more power than all the systems put together in winter.
They don't really tell you about this fall off in the solar marketing hype and it must catch a lot of people out.


I have 3 phase power and feed back to 2 Phases that have old spinny meters so I can use the grid as a battery. The 3rd phase is an electronic meter that registers input or use as a consumption.  Unfortunately the only thing that uses the 3rd phase  is the AC which is all our cooling and heating and even on one phase, is expensive to run.
To compensate for the 3rd leg usage I have an inverter hooked up to about 4 Kw of panels but only to one tracker to limit the output to that of close to what the AC uses.  I put a relay in the AC unit that is activated off the compressor.  When the AC Kicks in the power from the inverter compensates that phase. Being a DPDT relay, when the compressor is not running or the AC is off, the relay divers power to another phase to wind back some credit on the meters.
This way I can run the AC all day and only use 1-2 KWh of power on that phase instead of 14-16Kwh.
Don't work so well at night though!   :-[

last winter my solar couldn't keep up with demand on the 2 phases Due to 1 thing.
Heating.  That was for both the AC and the hot water.  I worked out that just the winter temp drop of the incoming water between summer and winter would use 3-4 Kw a day more energy in winter than the warmer start temps of the water in summer.  It adds up.

I have a few ideas to heat the house cheaply and with some independence of DIY thrown in.

First is  the 100KW gas  spa heater I have which I am going to convert to waste oil.  Simply remove the gas burners and replace with a DIY oil burner.
I'll circulate the heater water through a car radiator probably located in a back window in a housing and use the fans to pull air in or could just have it recirculating air in the house.  Obviously way overkill output wise but I can limit the burner output and will need to be run with someone at home and awake although I will see what over temps and controls I can put on it. The thing should be very stable, I have run hundreds of hours on the things but I'll locate it away from the house so it the thing does go up in flames, it won't matter anyway.  One reason I want to use hot water as the energy transfer medium and not just go direct air heating which would create a path for fire into the home.

I will be using metered ( Pumped ) fueling as gravity feed despite the simplicity everyone loves, is pathetically inconsistent for this application. Pumping the oil with the tank lower than the pump and burner means  no chance of run away  or the fuel flow getting smaller as the tank drains and thee is less head pressure.
 The base controls will be a thermostat that change fueling and air from the blower from Idle to heat as the temp of the water requires. I'll put in some various over temp cutoffs as well as a fuel cut as well.


2nd thought for heating was a used, 400L hot water heater to take advantage of the excess power I make. Due to several factors including poor grid voltage regulation, I have a high voltage problem which trips the inverters out.  It's actually better in summer despite much higher solar outputs because the grid voltage is a LOT lower I suspect due to everyone running their AC and maybe pool pumps etc. To stop the inverters re booting and turning off again all day, the procedure of which takes a couple of minutes, I have a voltage monitoring relay switch in dummy loads like a fan heater when the voltage gets high and the domestic hot water is already up to temp.

The thought with this 2nd heater which would be stand alone was I could use the excess power to heat the tank then circulate the water same as the oil heater to put warmth back in the house at night.
400L of water taken from 90c to 20C has 32Kwh of energy! Quite a good amount.  I then recalled that there is no way I'm going to have 32 Kwh of power to spare, not in winter anyway and I'ld probably want closer to 35 Kwh generated with losses to heat it.  That heat would be good to have at night and in the mornings though.

Follow on thought was to use the oil burner to heat the water that first heats the tank then goes to the radiator  so the tank always has the best storage capacity possible when shut down.
50Kw of output on the oil heater will be a walk in the park. That should give me enough to heat the house and the tank at the same time and finish with a tank full of hot water for later on. I'm more concerned about limiting the heat output of the burner than I am getting enough heat and with 100Kw potential, more than I'll need by far.


3rd option will be using a waste oil powered diesel engine to drive a 12 Kw Induction motor to backfeed the grid and just use my AC or resistance heaters.
 The winter fall off in generation is severe so although I shut down some of my solar in summer because I have more power than even running the AC 9-10 Hour a day can burn, in winter I come up short using the AC  as minimally as I can for heating.  The idea will be to fire up the induction motor, particularly on overcast days when the solar isn't doing anything significant and pump back some power to spin the meters backwards and make up for what I have used and maybe a bit of credit till the next read.  I then have to let the meters advance a bit and pay something as the price of being able to use the grid as a battery.

I only have 2 phases going to the garage which I want to upgrade to 3 phase but probably won't happen in time for winter as there are other renos planned and it will all be done at the same time along with some new high capacity circuits for the solar. The engine times might be a bit limited due to noise and running with the solar will again no doubt case the high voltage problem and trip the inverters out. Even in winter the grid voltages are well out of spec even at night so they can't blame too much solar input for that. There have been complaints made about the high voltage but so far, the power co's just make excuses it's intermittent and nothing they can do.  Installing some autotapping transformers that were made this century might be a start but anyway.

If I set the Motor up in a C2C configuration which combines all 3 phases into a single phase I will have 12KW potential, probably 9-10 practical output. This is never 100% efficent. in any case, too much for the wiring I have by far and probably more than I would have upgraded to anyway for any single phase.  I can educe output by slowing the motor however as with an IMAG speed is very directly coupled to output.
 If I run each phase individually, I'll have 4KW potential, probably 3 Kw Practical.  A little lower than I'd like. I don't know if it's possible to combine just 2 phases into a single. Probably might be with a capacitor across the motor terminals like a C2C but this would only be 2 C or 1C. More reading up, learning and testing required.

In any case, 3Kw input to 2 phases on an overcast on wet day is a lot better than nothing.  The run times to compensate the shortfall in solar is something I'll have to see about.


4th Idea is to use a 2nd hot water heater for the domestic supply as a pre heater for the main tank.
I have a 125L gas water heater I have set up several times with an burner to heat the water.  Once up to temp, the burner will maintain hot water in the tank is if is being  used constantly.  Set it up once at home and the whole family had the longest showers ever with the water never dropping off and costing nothing at all to heat.

If I can heat the tank once a day and have it feeding into the main tank, that could easily save me up to 12 Kwh a day that we used on average last winter.
This alone might be enough to get me to near break even on the power consumption even with no other changes. I could also use this as the heater for the house but I prefer the additional capacity of the spa heater and the better and more presentable packaging there of.
I want to do something to save costs but I don't want to turn the place into something that looks like the set of a mad max movie.  Presentation counts too.

This is also another possibility which will need investigating.
Mrs wants an outside Spa. Mate has one he wants to give away.  She sees relaxing soaks. I see 3000L of thermal storage right at the back door.
This thing is electric only but an oil fired heater would be the perfect match.  With that much storage even if the water was only taken to 50C ( don't know that the materials will take on those) that's over 100Kwh of heat! Good enough for 2-3 days at least.
Not sure about this, Trouble is if I get it,  it's a heap of work to set up an area and landscape it. Then again, could be a true asset for energy storage as well.

I'm thinking at this stage to try and work on all all these initiatives and then see which one is best or combination of a couple.
All have drawbacks.  The oil heater I probably would not want to leave going over night. I'll have to get oil and process it and, the biggest thing, it's hardest to set it up and blend in with the look of the house without detracting from the look and standing out like a sore thumb.

The generator WIll be noisy and also somewhat limited when I can and want to run the thing.  Spose I could set up up a remote shutdown at least so I don't have to go out in the cold  to turn it off or put it on a timer. Have radio switches already that would do the job.
Unfortunately there is no opportunity to co gen with my water cooled  lister and use the heat from the coolant. There is a place I could locate it at the end of the house but it would be very close to the neighbors and I can see that would quickly become a point of contention. I don't think I could enclose it in a small enough building to fit where I'd want to put it.  There are plans for an outdoor bathroom in that area and the engine would make it congested there and limit the open feel I want to get with the tropical feel bathroom. There is still the thing of running pipes  to where the heat would be most wanted which is at the other end of the house.
In any case I don't think the heat output would be adequate but if it was turning a 3 phase genny, could supplement the AC. Might be able to trailer mount it all and make it mobile so it could be set in place in winter and removed in summer. Spose if it was all built onto a trailer it could be sound proofed but it would weight about 3/4 ton all up with engine, alternator, trailer etc.  A lot for the Ride on mower to move as that's all that would fit round there, barely.

I think pretty much any of these  would allow me to catch up on the power I use. That said, I was pretty frugal with the heating last winter and not always as comfortable as could have been. The big oil fired heater would make sure the place could be toasty warm all the time. Which is really what I want. Too old and tired to be trying to save power/ energy now or running round with 3 jumpers on. I want to be comfortable first and foremost.
the other thing here is it gets cold enough so the AC is pretty useless at the real cold times anyway. Falls off the curve and makes bugger all heat. 

Oil is the way to go be it burned direct or in an engine as its reliable and can supply as much heat as I want.
None the less I do have some more panels to put up to hedge my bets but with winter fall off and orientation of the space left, I'm probably realistically going to be putting up 4 Kw of panels to get a Kw of generation back. Cost isn't the issue, I buy them used very cheap it's just the fact one is chasing ones tail with them in reality and then they are completely overkill in summer.

Wish I could find something to do with the excess power.  Spa might be an idea for that reason alone.

Interested to hear what other people do to offset their winter power use and heat their homes as well as any thoughts or heads up on what I am thinking.
 

Offline fourtytwo42

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Re: Winter heating and power generation ideas.
« Reply #1 on: February 16, 2019, 06:11:27 pm »
Hullo George, that's a very interesting description with lot's of idea's. Before I started in a small way with solar I invested a lot of time and energy in insulation to bring down my energy inputs in winter. Every loft/attic void is crammed full of insulation, the wall cavities are insulated and all the windows are double glazed argon filled.

I used a cheap handheld IR thermometer with pointing laser to find the cold spots, often around where windows had been fitted and odd places the wall insulation had not made it into (drill and fill with expanding foam).

Still have the same oil fired central heating but our oil consumption is dramatically down, fortunately we have a wood burner to supplement it in the evenings too.

The solar installation is primarily used to heat water in the summer so we do not have to use the oil boiler at all then saving wear and tear, we don't export any solar power at all as we wouldn't get paid for it.

So maybe before investing to much in meeting your present heating demand maybe you could consider reducing demand by improving insulation too as I guess you could spend the money either way and get a similar result :)

One difference here (apart from North/South that made me laugh) is we don't need Aircon in the summer so that's a huge saving.

4C sounds cozy too better than minus 4 or 10 that is typical for us!
 

Offline george80

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Re: Winter heating and power generation ideas.
« Reply #2 on: February 16, 2019, 10:43:31 pm »

There isn't many places to go with insulation apart from the double glazing.

I have a metal roof which is insulated underneath and I have batts on the ceiling... which I fixed shortly after moving in where the morons that did the ac pulled a lot away to install the outlets and of course couldn't be stuffed to put it back around.
There was also large sections missing completely around the downlights but seeing I have changed all the halogens over to LED, I could cover the lights up and leave the transformers sitting on the beams where they could get some air... not that they need much now doing about 1/10th the work they were before.

The double glazing here would cost a literal fortune with all the windows we have. I wish the place did have it though but I can't see it ever being viable.
This place is in a upmarket area and I have noticed that style gives away a LOT to function and efficency.  All the windows are nice but they are also inefficient unless double glazed.

One thing I am doing is sealing all the doors with foam tape. The place did have it but it's long since broken down.  Given how windy it can get here, drafts are another heat/ cold problem.

We used a LOT of aircon this summer.  2+weeks of 40 o weather with a number of 45's.  We are right out on the edge of Surburbia and the weather here is vastly different to the coastal areas. look on a map and 2 streets behind me and there is nothing but bush for another 4500Km till you hit the other side of the country.
It is 50Km  from the ocean/ city but the climate is SOOO different.  We had a number of Minus 4's and 5's  here last winter although funny enough, for some reason they didn't seem the coldest days.

ATM the nigh temps are falling to very fresh 12's or so. I was thinking of circulating water through a radiator with a fan at night outside to bring down the temp of my 3000L water tank then circulating again through the day to cool the place in the 30-35's we are having.

Should crunch the numbers on energy storage for that too!

I have been running a couple of car radiator fans over the man hole  blowing up into the ceiling. I have read numerous times keeping the ceiling temp down helps keep the house cool. My mate in AC also thinks the Roof temp has a significan't bearing on house temps.  Not normally one for DIY of this type but with his seal of approval it must be worth something.  I can't tell, have no way of measuring from one day to the next bat as the things ate Driven by a panel on the roof I had spare and costs me nothing, Figure It can't hurt if it Don't help.

The amount of air the fans move is surprising. Go to close the door of the laundry where the manhole is located and you can feel the significant air coming in and it is like the door is on a spring trying to resist it being closed. You can also hear the fan noise change pitch as they create a vaccum in the room and are starved for air.  there is a gap all the way along the ridge capping I an told is to let moisture out and I surmise over the length of the roof this allows the Hot air to escape and distributes the hot air expulsion right along the length of the house.

I was thinking in winter to reverse the airflow and pull hot air down and I investigated this last winter.
2 things made me do away with the thought.  Firstly, every time I get up there after a few minutes I start coughing. I'm not normally prone to that but up there it's continous. I don't think it is just dust, I tend to be more wary of the fibres of the insulation. If it is that I don't want it in the house although I could filter the air but....

Other thing was, In winter, it's not very warm up there at all.
Typical solar, never there when you want it most.  In summer it is unbearable up there. Few minutes is all one can take.  In winter, it's barely warmer than outside.
Couldn't see bringing the air down being worth the bit of power it would take.


 

Offline fourtytwo42

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Re: Winter heating and power generation ideas.
« Reply #3 on: February 17, 2019, 06:41:46 pm »

There isn't many places to go with insulation apart from the double glazing.

I have a metal roof which is insulated underneath and I have batts on the ceiling... which I fixed shortly after moving in where the morons that did the ac pulled a lot away to install the outlets and of course couldn't be stuffed to put it back around.
There was also large sections missing completely around the downlights.
I am not sure how thick your insulation is but all of mine is 300mm minimum and 500mm in the main loft/attic. When I got here it was 1970's 25mm, no use at all!

The double glazing here would cost a literal fortune with all the windows we have. I wish the place did have it though but I can't see it ever being viable.
This place is in a upmarket area and I have noticed that style gives away a LOT to function and efficency.  All the windows are nice but they are also inefficient unless double glazed.
It cost me a fortune too BUT only in small portions as I certainly did not try and do the whole lot in one bang! Fitting costs are fixed at days onsite so try choosing an amount they can easily do in one day (to much and you get a shoddy job) maybe four or five windows tops. I started with the largest windows that also happened to be the ones in the lounge where we spent our winter evenings. Next up was an old conservatory on the coldest side with no doors into the main building so impossible to shut off.

One thing I am doing is sealing all the doors with foam tape. The place did have it but it's long since broken down.  Given how windy it can get here, drafts are another heat/ cold problem. 
I have to have an airbrick(through wall ventilator) in the kitchen for the oil furnace and it also serves the woodburner but other than that we are tight, again it's amazing how good the IR gadget is at detecting leaking seals around windows and doors.

We used a LOT of aircon this summer.  2+weeks of 40 o weather with a number of 45's. 
I don;'t have that problem thank god, highest temps here maybe touch 30 occasionally, anyway at least your PV can look after your aircon in the daytime at least and if you have surplus PV perhaps you could think about storage for nighttime ?

I was thinking in winter to reverse the airflow and pull hot air down and I investigated this last winter.
2 things made me do away with the thought.  Firstly, every time I get up there after a few minutes I start coughing. I'm not normally prone to that but up there it's continous. I don't think it is just dust, I tend to be more wary of the fibres of the insulation. If it is that I don't want it in the house although I could filter the air but...

There are some air-air heat exchangers designed for air circulation systems you could use so you get the heat without the dirt! I had also thought on pulling heat from the attic but only works on sunny days when i don't need it :(

One last thing to mention I have big sunny side windows in the lounge and I get a lot of solar gain from them in winter, no blinds, no nets, like living in a goldfish bowl but.......
 

Offline george80

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Re: Winter heating and power generation ideas.
« Reply #4 on: February 17, 2019, 11:53:20 pm »
I am not sure how thick your insulation is but all of mine is 300mm minimum and 500mm in the main loft/attic.

Mine is nothing like that, it's about 50MM.

I have never even seen or heard of 3 or 500mm thick insulation. That is massive!

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It cost me a fortune too BUT only in small portions as I certainly did not try and do the whole lot in one bang! Fitting costs are fixed at days onsite so try choosing an amount they can easily do in one day (to much and you get a shoddy job) maybe four or five windows tops.

That is a great suggestion and way of doing things.


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anyway at least your PV can look after your aircon in the daytime at least and if you have surplus PV perhaps you could think about storage for nighttime ?

Have secured another batch of 260W panels and an inverter today. I'll pick them up later in the week and use these to replace some of the lower wattage panels I have.  only paid $400 for 4.6 kilo of panels and a 5 kilo inverter so I'll be able to sell the panels I replace for more than that pretty easily.  Might be able to put the profits to some new Windows.

Also lined up a new gen set for a couple of hundred  bucks.  It's only a little 3Kw alternator with a china Horizontal engine belt driving the alt which is how I like them but they work great on waste oil as I have 2 of these type engines already. Be good for a small backup genny when running a large one can't be justified.

On another Diy forum a few of us were discussing energy storage in the form of Ice. The phase change from liquid to a solid makes a HUGE difference in the energy in a given volume of water. Our thoughts were to get something like chest freezers and use excess solar to freeze the water we filled them with and have pipes running through we would fill with an antifreeze mixture to act as the working HE medium.

We found that no domestic Freezers had sufficent power to freeze their capacity in 24 hours. Unfortunate but not a deal breaker.
We next decided that the Ice expansion would probably split the units apart so that would be a problem  to solve, maybe putting containers within the units so as to give expansion room.  Doable.  Next some research showed commercial units that freeze water over night using off peak power and then use the ice the next day for AC had some very sophisticated ways of basicaly making a large surface area for the coolant pipes.

Ice is slow to melt and once there is an amount of water between the ice face and the surface of the pipe containing the water mix as the energy transfer medium, It kind of insulates and slows the melting process further.

It seems an easy thing to fill a freezer with water with coils of pipe running through it to cool a liquis which then ran through a HE but in prectice, it would be anything but easy to do this with practical cooling capacity. Unfortunately on that particular forum we tend to be a bit practical and Tea candle heaters and eskys full of ice with a computer fan blowing air in and out don't quite cut it with us.... By about a million miles.

I also set up an engine driven AC system using car units.  The AC from a car is equal to a medium/ large domestic split unit depending on the individual auto AC being used.  Pretty simple too, Turn the pump and give it some power for the Blower, fan, clutch and control and that is it.  had it running on LPG instead of refrigerant as that is effective and very cheap as well as being unregulated here like refrigerant.  Just put in some extra oil for the compressor and that's it really.
Gas volume is Different but instead of weighing it in I went by pressures. Easier and more precise.  Worked VERY well indeed.

Was going to put a reversing valve in the system so it could heat as well.
Not much for storage or using excess power but I could drive it with a large AC motor. The latter was not a problem I had when I set this up.  Threw it out Sans the motor when we moved here.  I can get all the components I want If I wanted to built another but not much use for such a system here.

Quote
There are some air-air heat ex-changers designed for air circulation systems you could use so you get the heat without the dirt! I had also thought on pulling heat from the attic but only works on sunny days when i don't need it :(

Another good Idea with the air to air.  I bought a BIIIG  truck inter cooler some years ago for this purpose. Had 4" inlet/ outlet and massive Flow HE capabilities.

I only did a test with it once over an oil burner as I was going to use it with and man there was some heat transfer going on there.  Could have heated the whole house in minutes with the airflow with a Jumping castle blower I had running through it and the  probably 80oC  air I had coming out the thing. Could have easily handled the output of 2 blowers I reckon and at very least 200Kw of burner underneath.  As long as the flame didn't touch the cooler itself and there was some cold air mixing It would have worked very well indeed. I was going to bleed excess air from the blower for the burner into the space between the burner and HE  to lower the gas temps.  With enough air running through the HE, It probably wouldn't have mattered that much as it would be internally cooled.

Got rid  of that too when I moved as I had too much junk and no purpose for it. Would have to take a section of roof off to get it in the Ceiling but not enough heat up there here to be much good. At my old house with un insulated Tiled roof, would have been a very different story.

Quote
One last thing to mention I have big sunny side windows in the lounge and I get a lot of solar gain from them in winter, no blinds, no nets, like living in a goldfish bowl but.......

I have doors and windows on the sunny side of the house and I was thinking of set back black drapes so the sun warmed them with passive air heating .  On a hot day I close that room off because the heat load is stupid. I was going to look at getting a small awning along that wall which would be designed to let the winter sun under and keep the summer sun off. One thought was to work out measurements and angles needed and see if I couldn't  make a frame and use solar panels as the roofing material. Gets all the ideal sun direction free and clear of any shading and I could get another 3KW worth of 250w panels along there.
 

Offline Kleinstein

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Re: Winter heating and power generation ideas.
« Reply #5 on: February 18, 2019, 12:57:27 am »
A 300 or 500 mm insulation is really thick.

One can approximately calculate the optimum amount of insulation from the prices of energy, insulation material and the expected temperature differences.  A at first odd point is that the optimum thickness goes up with the square root of the temperature difference only. So the best thickness should not vary that much with climate.

In Germany the building codes requires something like 160-200 mm (depending on the material and position). AFAIK this number is not that far off the optimum thickness for reasonable energy costs ( e.g. some 5 cent's / kWh) and average material costs. So the 50 mm might be still on the low side and it might be worth to add more where it is possible with not much higher costs than the insulation material itself (e.g. in the attic).

Windows can get you quite some heat from the sun, even without a black surface behind. Just a normal room tends to absorb most of the light anyway. This can help a lot in winter (and even more in early spring), but in the summer the heat can be too much. So one might want shades outside - these could be fixed to keep out sun coming from above, like an extended roof. So it would be a bout light colored drapes to reduce the heat load in the summer.

With cold nights in summer one might support the AC by having some heat storage and preferred ventilation in the 2nd half of the night. However heat storage is something best included when building the house, as it is heavy and easiest when part of the house (e.g. relatively heavy internal walls).

For the windows there is a big difference in just 2 simple panes and 2 panes with IR active coating. The coated windows can have 1/2 to 1/3 the heat loss, while just 2 simple panes is not that much better than just a single pane.  Numbers are around 4.5  , 3 and 1.3 W/K/m2.

Depending on how well the window seals are it may be worth looking at a system to use hear exchangers for the air coming in / going out and use active ventilation. However if not well sealed one may not need much extra forced ventilation.

With the temperatures in winter not that much below freezing, it may not be worth using ice as a heat buffer. Similar to a ice block, but sometimes easier to build, one can use the soil in something like 1 m below ground as a buffer. There are systems with underground heat exchangers (many meters of plastic tubing) to he used with a heat pump.  For the really cold days this is more effective than an air to air AC unit. For some reasons I have not seen combined units so far that depending on the temperature outside use the ground of directly the outside air.
 

Offline george80

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Re: Winter heating and power generation ideas.
« Reply #6 on: February 18, 2019, 04:22:21 pm »

I looked up insulation.
290Mm batts are the largest sold here. R7.0
Don't know what 500MM would be but they sound extreme.

I don't think improving my roof insulation would make any noticeable difference.  The glass is where the losses are in this house.
I will also probably gain some summer heat insulation when I put all the panels up particularly on the north facing roof of the house which is the optimum side here.
Just shadowing the roof with another layer I would imagine would have a significant effect on the heat loading.
Exactly the difference between having something in direct sun and under Shade.  Probably even more effective than that as you are keeping the heat out of the roof space to start with not trying to keep what is in there already out of the living areas.
 

Offline fourtytwo42

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Re: Winter heating and power generation ideas.
« Reply #7 on: February 19, 2019, 12:20:23 am »
I looked up insulation.
290Mm batts are the largest sold here. R7.0
Don't know what 500MM would be but they sound extreme.
Were probably talking about different types of insulation,  I am talking about fiberglass wool on a roll that you lay onto a flat surface, hence it is between the flooring joists over the ceilings, to make up the thickness I just add more than one layer (it comes in various thicknesses). Again I did not do it all a once but bought when it was discounted over several years. I have some vertical "stud walls" and these are insulated using the same stuff but with support strips of plastic stapled to the studs horizontally every 300mm or so, it is even possible to stuff between the rafters under the tiles using the same method to keep it in place. It is disgusting stuff to work with and makes you cough and itch even after a shower!

I have only used solid foam insulation in the conservatory roof, it's quite expensive and very messy when cut.

The "batts" you talk of are presumably semi-solid used in cavity walls during house construction ?

I don't think improving my roof insulation would make any noticeable difference.  The glass is where the losses are in this house.
I will also probably gain some summer heat insulation when I put all the panels up particularly on the north facing roof of the house which is the optimum side here.
Just shadowing the roof with another layer I would imagine would have a significant effect on the heat loading.
Exactly the difference between having something in direct sun and under Shade.  Probably even more effective than that as you are keeping the heat out of the roof space to start with not trying to keep what is in there already out of the living areas.

You would be amazed how much difference "ceiling" insulation makes upstairs, heat travels upwards so more is lost through a roof than windows, but I do mean ceiling not fitted under the tiles or the house heat is lost to the roof space. Like you say this has the double advantage of keeping the heat out in summer (not a problem we have here much).

Windows of course are also important and doubly so if the frames are badly sealed and they are drafty, I guess insulation is cheaper than double glazing so its tempting to do first :) But everybody makes there own choices based on local conditions, just watch for DIY bargains, sometimes insulation prices tumble when they think its been on the shelf to long!
 
 

Offline Kleinstein

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Re: Winter heating and power generation ideas.
« Reply #8 on: February 19, 2019, 08:19:06 am »
I would not add 200 mm or more. The return gets smaller at high thickness. So if 50 mm already there, maybe another 100 or 150 mm.  Often slightly thinker, lower grade insulation is the cheaper way than extra high grade, that is used when space is at a premium. How much it could help depends on the temperature difference. The current numbers could give an idea on what to expect.

The heat loss to roof and walls is not that different - it is only the convection that prefers the direction up. Radiation and thermal conduction goes not care about gravity. There may be slightly higher temperature in the air that make the roof loose a little more, but this difference gets smaller once the walls an floor are well insulated.

The solar panels one the roof can give some cooling in the summer and also some warming in winter. So covering the whole north side may help.

For the windows, replacing them would be normally more effective for the larger areas and the rooms that are warmer in winter. When looking for double pane, make sure they are coated and not just plane glass.

In some cases exterior shutters could be an option too, especially for the summer, but it also helps in winter. It really helps to keep the sun out.
 

Offline george80

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Re: Winter heating and power generation ideas.
« Reply #9 on: February 19, 2019, 02:28:58 pm »

This is the main sort of insulation we have here:

https://www.bradfordinsulation.com.au/home-insulation/ceilings/gold-ceiling-batts/overview#current

There are other types and brands but this is the most popular in oz and has been for some time.

The more I think about it, the more I believe for summer heat relief another verandah right along the back of the house to keep the sun off all together would probably be the most useful insulation and improvement.

That brings me back to my original post and reason for the thread however, winter heat and power generation.
Any thoughts or feedback on the proposed ideas there?
 

Offline fourtytwo42

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Re: Winter heating and power generation ideas.
« Reply #10 on: February 19, 2019, 08:36:46 pm »
This is the main sort of insulation we have here:
https://www.bradfordinsulation.com.au/home-insulation/ceilings/gold-ceiling-batts/overview#current
There are other types and brands but this is the most popular in oz and has been for some time.

I have used the stuff on a roll, the most popular here but very similar product
https://www.knaufinsulation.co.uk/products?product_range.0=Earthwool%20Loft%20Rolls

The more I think about it, the more I believe for summer heat relief another verandah right along the back of the house to keep the sun off all together would probably be the most useful insulation and improvement.

In your situation that may be so but IMOP does nothing for winter heat loss.

That brings me back to my original post and reason for the thread however, winter heat and power generation.
Any thoughts or feedback on the proposed ideas there?

That's maybe where we part our ways I think a severe lifestyle difference, yours IMOP is highly consumptive and mine is energy saving. You seem to be majoring on how to generate large amounts of heat and energy to maintain your high consumption and maybe increase it (spa) where as I start from completely the opposite premise, how can I save even more energy than I presently do!  I don't mean to be critical but as I say I think we have a different outlook.
« Last Edit: February 19, 2019, 08:43:17 pm by fourtytwo42 »
 

Offline george80

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Re: Winter heating and power generation ideas.
« Reply #11 on: February 19, 2019, 10:39:48 pm »
I don't mean to be critical but as I say I think we have a different outlook.

Yes I understand what you are saying and that is fair enough.

You have a little solar to heat water. I have a lot of solar to try and run everything I can from my own power rather than the grid.
Different approaches to what I think is probably a very similar outcome, reduction of costs and long term expense.

I thought of something this afternoon and went looking though the papers the previous owner/ builder of the house passed on. The batts insulation in the ceiling is R3.5.  This was the minimum standard when the place was built 21 years ago.  There is also the foil sarking under the metal roof, not sure but I think that is R 1.5.  If that adds up to 5 ) Not sure how insulation values work) then the insulation in the roof here is pretty decent.

I know there is also insulation in the walls but no idea what value that is. Could be 1.5 as well, may be higher, not sure.

The thing is it would cost me thousands to add more insulation and double glaze everything. I'd be surprised if it didn't cost me $25K plus. The cost of doing 7 Doors, 5 which are double and double insulating them might cost 25K on it's own.  It sure as heck wouldn't be cheap because I can see all the framing would have to be re done for a start.

I can generate my own energy FAR cheaper than what I could get a return on that even on an ongoing basis.  I buy panels once, just as I would insulation and they will last till I'm ready to move out.  I can get Veg oil to fuel generators and heaters for free. Yes there is work in it but to me it's a hobby and I deliberately always have gone to more work than necessary because it gives me needed exercise. Bit of a Labour of love.

The other thing is, If I invested the money in extra insulation in the roof which I think has questionable returns over the double insulation I already have, I don't see it being returned when I sell the place. I'm sure that sounds odd to many but I do know the local property market and there isn't a doubt in my mind i'd be far better off and get a much better return getting the place landscaped or putting in that spa than I would have trying to sell a well insulated home.

This area is upmarket and people have money and right or wrong, heating / cooling costs are way down the line of sought after features.
You only have to look in the town and see all the $50-100K vehicles parked which would well outnumber the Sub 10K cars  ( mainly being ours) to see this is an area of professionals not concerned about running costs of anything.

In any case, If leaving the place as is costs me $1000 a year extra in heating and cooling over what it might otherwise,  that will take 25 Years to break even and I don't think I'll be here then..... be here as in alive with what I have let alone here in this house.

You are right, I have no interest really in using less energy. I do enjoy creating energy at very low cost so I can have a comfortable lifestyle .
 I drive a big, heavy roomy, uneconomical 4WD truck which I love. I feel safe and secure in it and it does what I want and meets my needs.
I run the thing on veg oil so not only do I not have to pay high fuel bills, I pay a heck of a lot less than anyone running an econo car.
And that pretty much sums up my outlook. I'm not worried about what I use, I pay attention to being able to use it and it cost me the same as if I were miserly.

Trying to redesign the efficiency of this home would be extremely expensive. Doing the walls would just not be feasable for a start. Again I'm highly suspicious of what the savings would be if I did the roof to a higher spec and the windows and doors given I pay so relatively little now with the solar I have in place and am increasing as well as offsetting other ways. My power bill ( power being all we have) is about $1200 a year.  That may be a lot in other places  ( 30c kwh here) but it's less than 1/4 what anyone round here would expect to pay.  Pretty much spot on $400 of that is " Supply charges" which I couldn't avoid if I used $12 worth of actual power a year.

I would be happy if the place was better insulated and may take some steps in that direction but going much past a verandah and blinds I can't possibly see being economical especially if the things I want to do with more solar, generators and Oil heating bring those power bills down to even $800 a year.  The time it would take me to recoup costs of insulation and double glazing would take many more years than I believe I have left.

For those younger than me planning on living in their forever home, then the viability would likely make a lot more sense.

 

Offline IanMacdonald

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Re: Winter heating and power generation ideas.
« Reply #12 on: February 24, 2019, 08:03:09 am »
I have 300mm loft insulation and cavity wall insulation. The windows are rather old but they are double glazed. I still need heat in the winter, without which it would be down to about 5C or so. I reckon the claims of houses that don't need heat at all are BS, like most of the Green propaganda.
 
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Offline george80

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Re: Winter heating and power generation ideas.
« Reply #13 on: February 24, 2019, 07:19:12 pm »

I also believe many of the claims I have read of the lack of need or very minimal for heating or cooling in hot and cold climates are also to be taken with a grain of salt.

Unless your home is airtight and no one comes in through doors, there are going to be heat/ cooling losses.  Open the door and you leak heat out or cold in.  Insulation only slows heat transfer so if you live where there is snow on the ground for a month or is 40oC as we have had here more days than not last month. the place WILL heat or cool down to ambient in time.
Yes, your heating.cooling  bill will be much less than a non insulated home but you do have to have an input one way or the other.

I have been doing some passive Ventilation the last week. Opening doors and windows and using a solar Driven fan to Pull air into the house from outside. The air is nice and fresh here and I like to have air moving through the place when it does not have to be heated or cooled. Should be like this for another couple of months before it gets too cool.  Then I'll pull the air in to warm the place during the day and close up during the much cooler nights.

 

Online tautech

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Re: Winter heating and power generation ideas.
« Reply #14 on: February 24, 2019, 08:12:10 pm »
Up the insulation in just your main living areas with double glazing and ceiling insulation as this is where the most heat is lost. The whole house doesn't need to be warm.
A few W into electric blankets takes care of the night time bedroom chills.

Cold is a conceptual thing, we laughed our arses off at our daughter in law in Perth when they had the coldest Jan night last month with 17C. We were there and slept like logs while the locals froze there butts off.  :-DD

Oh, and thermal drapes can make a world of difference.  ;)
« Last Edit: February 24, 2019, 08:16:26 pm by tautech »
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Offline george80

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Re: Winter heating and power generation ideas.
« Reply #15 on: February 24, 2019, 10:55:57 pm »

Cold is a conceptual thing, we laughed our arses off at our daughter in law in Perth when they had the coldest Jan night last month with 17C. We were there and slept like logs while the locals froze there butts off.  :-DD

Can relate to that entirely.
I get asked to go up the Gold coast every July for work. My mate that lives there is bitching about the cold while wearing a jumper and all the locals are wearing jackets and Hoodies. The Mrs and I are walking round Surfers in T shirts and Shorts and still sweating!

Some years ago I played High rise babysitting as a building manager for a couple of places in the city.  The entire buildings were all climate controlled the same all year round.
You'd get calls from the tennants, could you come up and check the AC, something was wrong with it and everyone in there ( invariably women) were all freezing to death.  You'd go up, they would all be wrapped up like eskimos and at least half of them would have a fan heater under their desks.
You'd check the temp and all those heaters could have pushed the temp in there up a degree or 3 above what the thermostat was set at.
 
I'd stand, look, tap the read out, do something technical like turn the main switch for the storeroom lights on and off then close up the panel door and walk back and tell them very seriously I had turned up the thermostat quite a bit to get the temp up quickly for them but when it got too hot, let me know and I'd pop in and back it off again for them.

Of course I NEVER touched the damn temp setting from what it was ever.  23C all year round. NEVER any different.

Icing on the cake would be go back up or call 2-3 hours later and ask if they wanted me to back the temp off a bit if they were too warm now?
Oh no! It was perfect now,thanks so much for coming up and doing that for us. Sorry to trouble you but thanks so much, it's so much more comfortable in here now.  Oh Gawd!  :palm:
Same procedure for about 1/3rd of the tennants that also complained they were too cold. Should have won an academy award for that act!

Of course in Summer, it was too effing hot at the exact same temp and could you come and turn down the AC before they all passed out of heat stroke and died? Yeah sure, anything for you guys.   My actual work took all of about 60 Min a day If I dawdled and as long as the building didn't catch fire so the opportunity to stretch my legs and look busy was welcome.

The 2 Buildings had oversize AC that would cope with anything between Fireballs from space and Raining liquid Nitrogen and the Temps NEVER changed a single degree in the 3 years I was there. 
Back to visit what ever tennant, same concerned act and pretend I actually did something, tell them I have knocked it down quite a lot, ring ( or visit if the Chicks there were  good looking)  to make sure it's all good and they aren't too cold now and everyone was happy.  A few of them would beat me to the punch when I came up and did nothing, not that they knew that, and ring to thank me or even drop in the occasional bit of cake or bring me coffee in the mornings.  When I had meetings with the building owners ( same for both address) They always told me what good reports they got from the tennants as to how helpful and friendly I was and what a great job I was doing.  Yep, working my arse off flat out between 8 am and 5 past every single day.

Apparently I was much better than the old building manager because I came up and fixed the problems for them where the old Building manager before me just tried to convince them the temp hadn't changed from what it was before and they were imagining it. They weren't that stupid and he was just trying to fobb them off. 
What a bastard!      :-DD

Quote
Oh, and thermal drapes can make a world of difference.  ;)

I have heard this but it takes some imagining to me that something sitting off the window a good amount of CM can do anything at all.
Then again, we had thick Curtains in the last house at the front to keep the noise of the main road down.  That did work.

Last winter I tried putting sheets of Bubble wrap between the flyscreens and the windows.  Got a heap from a mate that was nice and wide so just hang a length over the screen, put it in place and trimmed off the excess. always a nice tight fit which I thought would do something itself with creating  an air pocket. No Idea if it did anything. Didn't even last a week till the mrs saw it, read me the riot act and went and took it all out.

Doesn't know about insulation, doesn't care and doesn't want anything detracting from the look of the place. Doesn't care about the bills either because they are so much cheaper than the other place with all the solar we have, she says just run the AC and be done with it.
 


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