Hot air wall design

[Daox]

Nice progress. It has been ridiculously cold this year. Its been the coldest year since I've owned my house (~5 years). Sure would have been nice to have this up I bet (I'm saying the same thing about my solar hot water setup haha).

[The master plan]

Finally got some time and warmer weather. Finished the outside wall, got some temporary inside ductwork done and the fan in. Waiting on my Digital Wind Speed Temperature Measure Gauge Anemometer from Amazon do do some testing. Trying this fan first...


Not sure this is going to work with this paint. It is a "energy star" paint. Not good...didn't see that until after the order was done. May try it this coming winter and then get it all off to get sandblasted and paint it with an absorber paint.



Whats more pressing at this time is the over-sized heat pump I got, or so I'm told. Cost wasn't much...but am afraid no of short cycling it. It will be drawing from a 1500 gal tank that is inside my craw space. Lots effort there...little cost. I intend to keep the tank between 40 and 70F.

I get heat from the city (when I run out of wood) in the form of hot water coil in a "gutted furnace" There is a meter that measures flow and they take the temp before and after the coil and bill in KWH. My house used 640 KWH last month...is that then 2,183,770 BTU of heat it took to keep me from freezing? Last May I ran out of wood also and used 1950KWH which would be 6,653,676 BTU's to heat my house, correct?? If so what size water to air heat pump would you recomend?

[AC_Hacker]

Originally Posted by The master plan

...My house used 640 KWH last month...is that then 2,183,770 BTU of heat it took to keep me from freezing? Last May I ran out of wood also and used 1950KWH which would be 6,653,676 BTU's to heat my house, correct?? If so what size water to air heat pump would you recomend?

If you know how much energy you used in the worst month, in terms of KW-h or BTUs or either or both this can be done.

It will be necessary to know your daily Heating Degree Day data from the closest possible data collection station.

What is your zip code?

What were your most severe months?

Do you have billing data from those months? It will be required to have the total energy used for each months billing cycle, AND the beginning date and the ending date for each months billing cycle.

If you were also heating the house with a non-metered heating source, fire wood for instance, this method will not work.

But if your heating sources were all metered, we can size your heat pump very accurately.

-AC

[Daox]

Do you not have any clear glazing over the black steel?

[The master plan]

No glazing over the steel yet.I'm sure it would help. But I'm not sure about the steel. Its painted both sides.

Everything I've read is that the heat transfer slows down if the paint is thick or in this case the heat has to go threw another layer of paint on the backside. It is what it is though...

Zip code is 56201...don't have the KWH heating for the coldest months. The two months I listed was city heat only, no other heat sources. During the winter I keep a low fire going in the basement stove 24/7. Total all last year was 5340 KWH but that is with 3 cords of wood used also. House is in dire need of more insulation and windows. If I'm not burning wood the furnace will run run, run, shut off for about 5 mins and run, run again. Thats why I burn wood. I plan on adding a layer or two of R10 foam board on the outside of the house and reside with vinyl siding later next year.

Really don't think a geo would work with my set-up until I get the house reinsulated anyway. This summer I will be opening up the inside north wall of the house and insulating that and replacing the 2 single pane windows. But would like to get the geo up and running to at least prove my design and get some numbers. It would be used as a sort of "back-up" heat this next winter, heating again by mainly wood. At least then if this geo idea doesn't work I'll at least be warm.

Getting bids for power to the garage and setting up for net metering...they make it hard for us here in town. Going to go with a Enphase system, start with a 1,020KW system when I do pull the trigger, again a year or so away. But I want all the ground work done first. The ultimate goal will be to get my electric and heating zeroed out.

More to come later....

[AC_Hacker]

Originally Posted by The master plan

Zip code is 56201...don't have the KWH heating for the coldest months. The two months I listed was city heat only, no other heat sources. During the winter I keep a low fire going in the basement stove 24/7. Total all last year was 5340 KWH but that is with 3 cords of wood used also.

Your yearly average heating degree days = 9059

This doesn't tell you anything except that it gets really cold where you live, but you knew that already.

The method I came up with is quite accurate if you can account for all the KW-h or BTUs you used during a particular period. With your heating methods I seriously doubt that you could account for how much heat you used.

So, getting back to your request:

> If so what size water to air heat pump would you recomend?

There is no basis for a reasonable guess.

You could go through THIS HEAT LOSS CALCULATOR and arrive at a close estimate.

* * *

Then again, I'd suggest that you tap into local lore and ask people who are in your area, because they have to contend with the weather you are facing... you might even get lucky and run into someone with a house that is in similar in size and similar in insulation.

That's probably going to be your best bet.

-AC

[Daox]

I definitely agree that insulation and sealing are your best bets for reducing your heating load. It sounds like it is very sizable.

[Mikesolar]

Originally Posted by The master plan

No glazing over the steel yet.I'm sure it would help. But I'm not sure about the steel. Its painted both sides.

..

You will at least double your heat output with glazing. Stove paint is fine for steel. There are better paints but harder to get.

[The master plan]

You will at least double your heat output with glazing. Stove paint is fine for steel. There are better paints but harder to get.

I have a roll of factory made "special coated" black with rippled steel I bought from a guy around here. The back side is bare steel to transfer more heat. I'm going to compare the two in temps side by side.
This guy built his house with a thick layer of sand over large pipes, then used a hot air system to heat sand under the slab and he'd blow air back threw at night to recover the heat.

Outside this winter the two different steels stayed pretty close together on surface temps with the sun shining. Its an open system now, drawing in cold air. But I'm interested in what will happen to my air temps if its a closed loop?

I used some of the special black steel coil to build a 4X8 and a 4X16 panel a few years ago, unglazed also. But would get alittle better temps. I suppose the large amount of steel I have now exposed to the cold air in killing performance also. But I'll have to wait on glazing until later. 300sqft of glazing = $$ and its sounding like its getting to be more expensive to get more power than the extension cord I have now out the garage. 3 quotes and 3 different ideas about how to set up a net meter from the garage to the grid. Main power comes in to house from underground city. May try a 4th quote just for good measure. lol