Quick Answer
Solar hot water can be used for space heating, but it's essential to use a system designed for such applications, such as a solar thermal system with a heat exchanger or a tankless coil. These systems circulate a fluid through the solar collectors and then transfer the heat to a water-based space heating system. ---
Choosing the Right Solar Thermal System
For space heating, you’ll need a solar thermal system capable of producing high temperatures (often above 180°F). A drainback system is a popular choice, as it eliminates the risk of fluid freezing in the collectors. These systems work by circulating a non-freezing fluid through the collectors and back to a storage tank, where it’s heated further. A typical drainback system consists of a pump, tank, and collector array. The pump circulates the fluid through the collectors, and the tank stores the heated fluid for later use.
System Design Considerations
When designing a solar thermal system for space heating, consider the following factors:
- Collector size and orientation: Aim for a collector area of at least 10-15 square feet per 1,000 BTU/h of heat demand.
- System insulation: Ensure that all components, including the tank and pipes, are well-insulated to minimize heat loss.
- Heat exchanger type: Use a tankless coil or a plate heat exchanger to efficiently transfer heat from the solar fluid to the space heating system.
System Performance Estimation
To estimate the system’s performance, calculate the collector’s peak output in BTU/h and compare it to your space heating demand. A typical solar thermal collector can produce around 1,200 BTU/h per square foot of collector area. Assuming a 10-15 square foot collector per 1,000 BTU/h, a 100 square foot collector array can produce around 12,000-18,000 BTU/h. This can potentially cover a significant portion of your space heating demand, especially in mild winter climates.
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