We design and install close-coupled and pump-circulated solar water heating systems.
In a “close-coupled” SWH system, no pumping is needed because the storage tank is mounted above the solar collectors on the roof and the hot water naturally rises into the tank through thermosiphon flow.
In a “pump-circulated” system the storage tank is mounted below the level of the collectors, so a circulating pump moves water or heat transfer fluid between the tank and the collectors.
SWH systems are designed to deliver hot water for most of the year, even during a Maine winter. However, there sometimes may not be sufficient solar heat gain to deliver sufficient hot water and a gas or electric booster is used to heat the water.