hikermor... I built a solar water heater for Mom and Dad when I got out of the USAF around 1976... a local entrepreneur had come up with a pretty good model... it used the 3 sided aluminum extrusions that swimming pool enclosures were made from... the lip of the extrusions held 4 pieces of 2'x 4'glass... base was a piece of 1/2" 4x8 plywood sheathed on the outside with a couple of sections of alum ridge valley... the lip of the 3x4 box beam allowed some additional space to accommodate the glass in a standard un cut form

he used 3 pieces of redwood with a series of V notches cut in to hold the 1/2" type M rigid copper pipe down to the collector plate... the pipe loops were connected by a street elbow and a 90 degree fitting... pipes were about 7 1/2ft long... 220ft of pipe in each of two collectors... two redwood spreaders on saw horses held the sections of pipe and connectors to be sweat soldered during construction... the spreaders were of the height to support the edges of the glass(held in place by a piece of polymer glass molding with edge notch to hold the glass, yet allowing it to "float"... edge of the glass held with a piece of 90degree alum angle...as well as the receiver box... mounted off the roof on pieces of aluminum stand off

the collector plate was a piece of the heavy aluminum "foil" backed insulation used in building A/C ducts... pipe and collector painted black...

a small magnetic pump produced water flow, and was controlled by 3 temperature controls that clamped on the pipe, and a powered gate valve... a special 82gal hot water heater that had a fitting from the base of the tank was used... the "demand" controller was clamped to a line from the lower (cooler) part of the tank... it was in series with a controller in the collector that sensed enough heat.. the third controller was a freeze protection circuit that ran water through the system to prevent freezing

on a sunny day it would produce 82 gallons of 180F water by Noon...visiting relatives would have to be warned of the heat......

we anticipated that the less than $700 cost would be returned in 5 years in power bill savings... it took 3... it was removed after Mom and Dad's death when I inherited the house...I had the roof replaced at about 25years of service from the collectors and they needed some repair... my mistake was that I had run the service lines across the top of the roof, and they had frozen on a couple of occasions, causing problems with the collector coils rupturing

I was referring in my comment to hurricane solar... regards