solar hw

Constantin

I would run the supply into the solar tank, then use the output from the solar tank as an intake for the gas water heater. That minimizes the temperature in the WH that the solar is trying to heat, maximizing its efficiency.

In an ideal world, you'd do it with two indirect water heaters or a single WH that has two coils. Gas water heaters are notorious for losing energy via the unlined chimney stack in the middle, so you will not realize the full benefit of a solar hot water pre-heater with this system.

What you can do very inexpensively is retrofit a <a href="http://www.gfxtechnology.com">GFX heat exchanger</a>, which will work with any heating system and which will stretch the hot water supply considerably.

Another thing to consider is to buy <a href="http://www.ecs-solar.com/lessons_learned.htm">Lessons Learned</a> before embarking on any solar project. Lots of experience in that tome.

shawn_10

Does anybody have any diagrams for a solra hot water heater to run in conjuction with a gas water heater.

Ed_26

solar dhw

Go to: www.solarThermal.com or google solar dhw.

ALH_4

Solar Energy

When using solar energy, the useful dT of the storage tank is very important. This is why solar domestic hot water systems generally consist of two tanks as Constantin stated. The solar "fired" indirect hot water tank is fed by the cold water supply. The conventional hot water heater, either direct-fired or indirect-fired, is fed by the hot water from the solar storage tank. A very important point is to use an anti-scald mixing valve to temper the hot water to your fixtures. The water in the pre-heat tank is heated as hot as possible to maximize use of the solar collectors. Ideally the solar pre-heat tank cycles from its max of 160F to the temperature of your incoming water every day, matching the diurnal input cycle from the solar panels.

-Andrew