05-24-2008, 04:32 PM
We have solar hot water and it works great. The only problem is that there is no anti-scald valve at the water can get very hot.
The systems are sized according to the amount of average sun hours in your area. A system in Puna will usually have two panels, a system in Kona one. We have an 80 gallon tank and a passive system.
A passive system has the storage tank on the roof and sits above the solar collectors. By convection the hot water rises and the cold sinks generating the necessary circulation to keep the water hot.
It only takes a few hours of moderate sun to heat it up and three or four really gray days to run out of hot water. There is a back up electric element in the tank but we keep it off most of the time.
The other common type of system is considered an electric (or gas) water heater with solar backup. You have a larger than normal hot water tank at ground level and solar collectors on the roof. A small pump on the hot water tank circulates the water though the collectors. There is a thermostat on the pump to turn it off at night and when the water is hot enough.
I like the passive systems best--fewer parts, less electric usage.
Jerry
Art and Orchids B&B
http://www.artandorchids.com
The systems are sized according to the amount of average sun hours in your area. A system in Puna will usually have two panels, a system in Kona one. We have an 80 gallon tank and a passive system.
A passive system has the storage tank on the roof and sits above the solar collectors. By convection the hot water rises and the cold sinks generating the necessary circulation to keep the water hot.
It only takes a few hours of moderate sun to heat it up and three or four really gray days to run out of hot water. There is a back up electric element in the tank but we keep it off most of the time.
The other common type of system is considered an electric (or gas) water heater with solar backup. You have a larger than normal hot water tank at ground level and solar collectors on the roof. A small pump on the hot water tank circulates the water though the collectors. There is a thermostat on the pump to turn it off at night and when the water is hot enough.
I like the passive systems best--fewer parts, less electric usage.
Jerry
Art and Orchids B&B
http://www.artandorchids.com