Solar Warm Air Systems This section is a brief review of solar warm air systems and concepts.
Solar warm air collectors are the simplest to install.
Best use: daytime space heating
Secondary use: domestic hot water
Cost: least expensive
Installation: usually roof mount, also ground mount or directly to the side wall of the house
Solar warm air collectors are connected together with flexible ductwork and use a blower to move the air from the collectors into the heated space. The blower is turned on by a switch or controller.
Solar Warm Air System -
A Typical Installation Model for Residential Rooftop.
Solar Warm Air Collectors on rooftop with ductwork in attic.
Solar air collectors are about 4 feet wide and 8 feet long.
The solar collectors need to be facing south with a steep inclince to maximize the exposure during the winter months.
This diagram shows solar warm air collectors on the rooftop with ductwork in the attic.
The blower is also in the attic pulling supply air through the collectors and pushing the solar heated air into the conditioned space.
Solar Warm Air Components Diagram
The solar components of a warm air system include; collector, blower, flexible ductwork control system and vents.
The blower is sized acording to the number of collectors and total length of the ductwork. Larger systems with four or more collectors may have more than one blower.
The flexible ductwork is used because it is insulated to keep from losing the heat while air is traveling into the conditioned space.
The control system may be a "temperature differential controller" which uses sensors to compare inside temperature and collector temperature. When the collector temperature is warmer than the inside temperature the blower is turned on to move the heat. Warm air systems sometimes use "bi-metallic" snap switches inside the collector to control the blower.
Vents are needed to attach the flexible duct. One vent is located near a floor to pull cooler inside air to the collectors. One vent is located near the ceiling to push solar heated air into the conditioned space.