Water heat storage for solar hot air system.

[menaus2]

Baffle in place.



Baffle insulated on inside and painted. You can see the 3/4" metal conduit support bar as well. The side 2x8s are painted with several coats of primer and gaps with the siding are being caulked in.



One side of the two layer screen absorber. because of the height of the panel the absorbers are placed in a "sideways V" arrangement. Heres what it looks like from the right side view:
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Closeup of the screen absorber. This is just the first layer above the baffle.



Detailing the sides. The clear suntuff type polycarbonate will go over this so i want it to look nice



Another shot of the support bar. You can also vaguely see the 2 layers of screen in place.



Polycarbonate starting to go up. Its sealed with silicone caulk and secured with rubber washer roofing screws. There is a vertical wood bar up the middle to secure the 2 polycarb sheets together.



filling in the top.



Top done. The top is insulated on the inside with 2 layers of polyiso. The exhaust wraps around the side of the house into the units kitchen. the ducting is currently insulated with a polyiso box filled with sprayfoam (i like sprayfoam ) The very top is also insulated with spray foam. The exhaust boxing and angled top detailing will wait till spring.

The blower is a Suncourt TF104. It's controled by a plug-in thermostat (commonly used in greenhouses). It has an electronic sensor so i simply extended it from the furnace room into the panel with some thermostat wiring. The exhaust has a hinged dryer vent to prevent backflow.

[Mladen]

Have you considered using some air valve to prevent heat lost during night and periods without sun?

[menaus2]

Yup I made sure to do that I simply put one of those dryer exhaust vents with the little flaps on the inside wall where the panel exhausts to prevent backflow of the air.

My renter said that it gets pretty toasty when the panel is going. The sensor is placed about halfway up the panel and set to turn on at 100 deg. F, so the bulk of the air is probably hotter than that. I haven't timed it, but on a good sunny day the blower comes on in about 15-20 second intervals.

I'd say it adds about 5 degrees in the apartment. I'm basing this off the temperature differential between this and the adjacent unit. The thermostat is located in the apartment with the panel, which unfortunately means the adjacent unit gets down to 64-65 ... Guess I'll just have to build another panel! I'm wondering if it would be worthwhile to heat the basement with solar so it heats more evenly? :/

[menaus2]

Just an update on the system. I resolved the thermostat issue by simply raising the set temp a degree or two higher. Other than that I've been very pleased with the system's performance. The heating season here in Wisconsin is basically over, so I've unplugged it for the summer. Also, I was able to fully depreciate it on my taxes as it was an energy property.

Quick question though for everybody, would you be concerned about high stagnation temps? Would the polycarbonate glazing have enough heat loss to keep it from self destructing? I have foam wiggle strips I can take out at the top for ventilation, but I would rather not have to get up on a ladder twice a year if I can avoid it.

I'm also looking at getting a new temp. controller from myDTC. I'm unsure if I'd be able to use 3 sensors: one each for panel, indoors and outdoors. So, say It'll turn on when the panel is over 100 f, it's under around say 70f inside and outside. I also cant find any material if the relays can control the 120v ac blower.

[GaryGary]

Hi,
My experience has been that single glazed vertical collectors are OK in through the summer stagnated.

The one I have on my shop does not go above 185F when stagnated.

Still not a bad idea to monitor the temperature for the first year.

Warm Fall days may produce higher temperatures than mid-summer as the sun get lower and you still are not using the heat.

Gary

[Daox]

I know this year was really warm, and hard to compare to previous years. But, do you think you can provide any additional details on how the system works? Like what kind of benefit it provided, or any other semi-measurement of its performance? How often, or under what conditions did it turn on?

[menaus2]

Hi Doax,
I wish I had some hard data to go off of, but I haven't really had a chance yet. Maybe that's something I could spend a sunny afternoon logging the temp rise. Circumstantially, the renter mentioned on on sunny days the apartment would get pretty toasty, and on one day with outdoor temps around the low 70s it got around 78 inside. I think this pretty consistent with the 5 or so degree rise I've seen from the heater. I want to put up another hot air panel this summer, so I'll have records to compare what that does.

[menaus2]

If I install solar hot air panels in the other 3 units, I think I might have to install TRV's (Thermostatic Radiator Valves) to prevent overheating in the rooms and generally be able to realize heating gains from the Central heater.

[frankwest12345]

Hi, great project but I thought you were supposed to circulate the air in and out of the same room, you seem to be taking air from the basement into the kitchen, does this make a difference to the performance?

[menaus2]

Hi,

The blower actually pulls the air from the same room, it's just that the ducting runs through the basements for a few feet. It's a more convenient location for the blower.