Saturday, May 23, 2009
What about Evacuated Tubes vs. Flat Panels vs. Thermosyphon Panels vs. U-Pipes?
Evac Tubes are great for hot summer days to sub zero temperatures, and can go on the ground, slanted against a house wall, or on the roof. They are not affected by wind or outside air temp and produce heat with all sun angles 360 degrees.
Flat Panels are great for very hot to nearnfreezing temperatures, and can be placed anywhere also. But, they are limited to southern exposure and their efficiency is reduced in freezing areas or cold windy areas.
It all depends on your location:
In the sunny middle of the country, one of our Solar Evacuated Tube Panels will produce an average of 9,000,000 Btus per year, or 290,000 Btu's per year per sq ft at an initial panel cost of $38 per Sq Ft. On a bright winter day they will produce an average of 1,400 Btu's per Sq Ft per day.
In the sunny middle of the country, one Sq Ft of our Solar Flat Panels will produce an average of 294,000 Btu's per year at an initial panel cost of $32 per Sq Ft. On a bright Fall or Spring day they will produce 1,418 Btu's per Sq Ft per day. If you are in an area where near or below freezing temps are normal for the heating months, then Solar Flat Panels will not produce enough energy to match the Evacuated tubes. Solar Evacuated Tubes would be the proper and efficient Solar Panels for that climate.
Flat Panels are more efficient in warmer climates than Evacuated Tube Panels, as Flat Panels are affected by outside air temp and cold wind. Evacuated Tube Panels are more efficient in warm to sub-freezing climates, as they are not affected by outside air temperature or cold wind, and absorb available sunlight from 360 degrees.
Thermosyphon Panels are very simple and should be placed on the ground near the house. They are great for areas with freezing to hot temperatures and used with an open loop, i.e. city, cistern or well water is heated directly in the panels and goes right into your Domestic Hot Water Tank for house use.
U-Pipes use evacuated tube technology but can be placed flat, sideways or vertical... as against a balcony railing or on a south house wall.