SunTechnics Energy Systems - Solar Thermal

Solar Water Heating | Pool Heating | Radiant Floors | Incentives | Products

Premium products for maximum solar performance

SunTechnics provides high quality solar thermal products to fit your every need. Systems are designed to be durable, long lasting, and have outstanding warranties. We will customize the best product for your home and lifestyle requirements.

Passive Solar Water Heating Systems
Passive systems have the advantage of continuing to work during power outages. They are less expensive, more reliable, and easier to maintain than active systems but can only be used in mild climates where the pipes carrying water to the system will not freeze.

Active Direct Water Heating Systems
In a direct (open loop) system, water is circulated directly into

the collector from the storage tank, typically a backup hot water heater. There are two types of active direct systems: draindown and recirculating. In both, a controller activates a pump when the temperature in the collectors is higher than the temperature in the storage tank. In the draindown system, a valve operated by the controller allows water to drain from the collector when the temperature approaches freezing. In the recirculating system heated water is pumped from the storage tank through the collectors when the temperature drops to 38°F.

Active Indirect Systems
In a closed-loop antifreeze-heat exchanger system, an expansion tank allows antifreeze to expand and contract as the temperature changes. A number of valves and gauges are needed to protect the equipment and keep the system working well. A pressure relief valve protects against excessive pressures in the closed loop; a spring loaded check valve guards against reverse flow at night so the collectors won't dissipate the heat from the storage tank; and an air vent helps get the air out of the closed loop (since it can block fluid flow through the system).

A pressure gauge will indicate whether the system is still charged with antifreeze, and a temperature gauge will indicate how well the water is being heated. Systems that use antifreeze fluids need regular inspection (at least every two years) to verify the viability of the antifreeze solution.

Drainback, a simpler indirect system, which can use distilled water or antifreeze as the heat transfer medium, automatically drains the collector whenever the circulating pump stops. It includes a valve that will purge the water in the collectors when the outdoor temperature reaches 38ºF. When the temperature is higher than 38ºF and the collectors are hotter than the storage tank, the valve allows the system collectors to refill and the heating operation resumes. Since the collectors will only have water in them when the pump is operating, there will be no fluids in the collector at night, or in case of power failure, that could possibly freeze or cool down and delay the startup of the system when the sun is shining. This is a simple, reliable failsafe system.

SunTechnics Energy Systems, Inc. | 1-888-786-8321 | SolarInfo@SunTechnics.com