Thursday, January 10, 2013

Solat Water Heater Diagram

Our solar water heater will use standard parts. It will include two standard electric water heaters, one will be used as a solar tank. The heat will be transferred to the main water heater with a heat exchanger. The two electric heating elements will be removed from the solar tank, providing two access ports to connect the heat exchanger. The lower heating element on the main tank will also be removed, and a special tee will be connected to provide inlet and outlet to the heat exchanger. The upper heating element will stay for backup. The temperature settings will be 140F for the solar tank, and 130F for the main tank. A mixing valve will keep the hot water going out at 100F. The electric element will be set at 100F, which will be the min hot water temperature. Total cost (not counting the existing water heater) is about $1200. Payback is 2 years, assuming $50/month savings.
Assembly should start soon, and hopefully it will be installed on time to collect some of our summer heat.


  1. Looks like this plan is not going to work, due to the heating element ports being straight threads, while NPT threads are conical. It is probably best not to touch those ports. There are several options. The Build-it-solar system is best for the solar tank, with a pre-heating heat exchanger made of pex. The main electric heater tank may be kept at temperature by taping the drain outlet, which is standard thread, and connect it to another pex heat exchanger inside the solar tank. That would probably be the most practical system.

  2. Thank you for sharing. Did you know the life expectancy of the average water heater is 8 to 12 years?
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  3. You have brought up very fantastic points, thank you for the post.installers