CSLB C-46 Solar ContractorSolar Thermal System InstallationEasy
A solar thermal installer is integrating a new domestic hot water (DHW) system with an existing conventional water heater. The solar pre-heat tank needs to be plumbed in series with the conventional heater. What is the correct piping configuration to maximize solar contribution?
- AConventional Heater -> Solar Pre-heat Tank -> Cold municipal water -> Hot Water Fixtures
- BCold municipal water -> Conventional Heater -> Solar Pre-heat Tank -> Hot Water Fixtures
- CSolar Pre-heat Tank -> Cold municipal water -> Conventional Heater -> Hot Water Fixtures
- DCold municipal water -> Solar Pre-heat Tank -> Conventional Heater -> Hot Water Fixtures
Show answer & explanationAnswer & explanation
Correct answer: D. Cold municipal water -> Solar Pre-heat Tank -> Conventional Heater -> Hot Water Fixtures
To maximize solar contribution, the cold municipal water should first enter the solar pre-heat tank, where it is heated by solar energy. This pre-heated water then flows into the conventional water heater, which only needs to raise the temperature further if the solar input is insufficient.
Why the other options are wrong
- A. This configuration is illogical and would not function as intended.
- B. This configuration would heat water twice unnecessarily or reduce solar contribution.
- C. This configuration is illogical and would not function as intended.
Solar DHW Series Plumbing
Connecting a solar pre-heat tank in series with a conventional water heater to use solar energy for initial water heating.
- Cold water first enters the solar tank.
- Solar-heated water then feeds the conventional heater.
- Maximizes solar contribution and reduces conventional heater workload.
Memory trick: Cold in the solar, then to the heater, for hot water that's sweeter!