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gtojohn · 03-21-15, 04:10 AM

I found a little info today. "For flat panel collectors expect 1000 btu per sqft per day in the south. In a more northern latitude expect 750 btu*sqft day. 10-20% of building sqft was recommended for sizing to provide 25% of annual heating demand. Also recommended 5 gallons of water per sqft of panel for storage will increase coverage to 50% of annual heating demand."
So in theory I can expect 63,000 btu output on a sunny day and 315 gallons of storage can help buffer for a cloudy day. Im already undersized for a 1000sqft space, man j shows 11kbtuhr on a 30f day (264kbtu day). Manipulating manual j with the panels I have I can expect to keep 6f above outdoor ambient. So, 240 sqft could help keep me closer to 18f above outdoor ambient and quite a bit more comfortable as a starting point before other heat sources.

03-21-15, 04:10 AM	#17
gtojohn Journeyman EcoRenovator Join Date: Jul 2014 Location: Austin, TX Posts: 314 Thanks: 39 Thanked 50 Times in 45 Posts	I found a little info today. "For flat panel collectors expect 1000 btu per sqft per day in the south. In a more northern latitude expect 750 btu*sqft day. 10-20% of building sqft was recommended for sizing to provide 25% of annual heating demand. Also recommended 5 gallons of water per sqft of panel for storage will increase coverage to 50% of annual heating demand." So in theory I can expect 63,000 btu output on a sunny day and 315 gallons of storage can help buffer for a cloudy day. Im already undersized for a 1000sqft space, man j shows 11kbtuhr on a 30f day (264kbtu day). Manipulating manual j with the panels I have I can expect to keep 6f above outdoor ambient. So, 240 sqft could help keep me closer to 18f above outdoor ambient and quite a bit more comfortable as a starting point before other heat sources.