re: simple system query
8 feb 2003
>>the 1000w peak collector is made up of 20 thermal diode evacuated tube
>>heat pipes... the collector has an anti freeze valve attached to leak
>>out water should the pump stop and the temperature falls below 40f...
>>...it was cheap with the only significant expenses being the collector
>>($1000), pump ($120), anti freeze valve ($100) and the heat exchanger
this one-of-a-kind solution might change if mass-produced. electronics
(vs "hardware" like evacuated tube collectors or antifreeze valves) can
be very cheap if produced in large volume, eg 1,000 or 10,000 systems.
a differential thermostat with 1) a draindown conventional or trickle
collector and a vertical heat exchanger next to a water heater or b)
pressurized fin tube pipe or big fins in a sunspace with recirc freeze
protection could be less expensive than your solution, in volume.