EcoRenovator - View Single Post

MN Renovator · 03-23-13, 06:53 AM

ok. I did some hourly averaging of the solar radiance readings and then added the cumulative total of wh radiance per SqM and it looks like 2401wh/sqm. 8536.9wh(29128BTU) of sun over a 4x8 surface minus the losses in the process and worse would be the cloudy days where this might do very little but on a good day. Basically a space heater running for nearly 5 hours(considering an hour loss due to losses in the system from conduction from the glass and wood) on sunny days with something primarily constructed out of wood. Taking a look at all of the winter days where my furnace would be running about 30 minutes less for that day and being slightly more comfortable inside, I think I might build two of these. If I had one it would have likely wiped out about 10 hours of furnace time so far this month. I think it would have been worth more than $5 of heat savings this month. The advantages would be greater in January where I dip into the furnace startup setpoint more often and could stand to gain the heat. Figuring I get half of the 'nameplate heat' versus a good day that would save about $5 in the less sunny November through February months. $20 savings per panel through the worst months, I figure. $100 after 5 years, I'm game.

Of course these are wild guesses. I do know of a couple in Minneapolis who has installed two commercial solar hot air panels in their upper level and they love them but the warm air upstairs isn't helping out the downstairs as its not moving down there on its own. May have been a better idea to have punched the holes in the house downstairs and figure that convection might help out with getting the heated air upstairs to be more even throughout the house. Either that or the solar installer might have been hoping to come back and install another one or two downstairs.

Grainger sells 90 degree on, 80 degree off snap switches to help control your fan for DIY panels.

03-23-13, 06:53 AM	#6
MN Renovator Less usage=Cheaper bills Join Date: Nov 2010 Location: Minneapolis, MN Posts: 939 Thanks: 41 Thanked 116 Times in 90 Posts	ok. I did some hourly averaging of the solar radiance readings and then added the cumulative total of wh radiance per SqM and it looks like 2401wh/sqm. 8536.9wh(29128BTU) of sun over a 4x8 surface minus the losses in the process and worse would be the cloudy days where this might do very little but on a good day. Basically a space heater running for nearly 5 hours(considering an hour loss due to losses in the system from conduction from the glass and wood) on sunny days with something primarily constructed out of wood. Taking a look at all of the winter days where my furnace would be running about 30 minutes less for that day and being slightly more comfortable inside, I think I might build two of these. If I had one it would have likely wiped out about 10 hours of furnace time so far this month. I think it would have been worth more than $5 of heat savings this month. The advantages would be greater in January where I dip into the furnace startup setpoint more often and could stand to gain the heat. Figuring I get half of the 'nameplate heat' versus a good day that would save about $5 in the less sunny November through February months. $20 savings per panel through the worst months, I figure. $100 after 5 years, I'm game. Of course these are wild guesses. I do know of a couple in Minneapolis who has installed two commercial solar hot air panels in their upper level and they love them but the warm air upstairs isn't helping out the downstairs as its not moving down there on its own. May have been a better idea to have punched the holes in the house downstairs and figure that convection might help out with getting the heated air upstairs to be more even throughout the house. Either that or the solar installer might have been hoping to come back and install another one or two downstairs. Grainger sells 90 degree on, 80 degree off snap switches to help control your fan for DIY panels. Last edited by MN Renovator; 03-23-13 at 06:55 AM..