Quick Answer
Recommended pump types for solar hot water systems include diaphragm pumps and submersible pumps. Diaphragm pumps are well-suited for solar hot water drainback systems, as they are non-corrosive and can handle low pressures. Submersible pumps are often used in solar thermal systems due to their ability to withstand high temperatures and pressures.
Choosing the Right Diaphragm Pump for Solar Hot Water
When selecting a diaphragm pump for a solar hot water drainback system, it’s essential to consider a few key factors. The pump should be designed for low pressure and high flow rates, as solar hot water systems often require efficient heat transfer. A pump with a maximum operating pressure of 10-15 psi (0.7-1 bar) and a flow rate of 10-20 gallons per minute (38-76 liters per minute) is a good starting point.
Submersible Pump Selection for Solar Thermal Systems
For solar thermal systems, submersible pumps are often the preferred choice due to their ability to withstand high temperatures and pressures. Look for a pump with a maximum operating temperature of 180-200°F (82-93°C) and a pressure rating of 50-100 psi (3.4-6.9 bar). A submersible pump with a flow rate of 20-50 gallons per minute (76-189 liters per minute) can efficiently circulate hot water through the solar thermal system.
System Design Considerations
When designing a solar hot water system, it’s crucial to consider the pump’s placement and configuration. In a drainback system, the pump is typically located at the bottom of the storage tank, where it can easily circulate the water. In a closed-loop system, the pump may be located in a separate enclosure, away from the solar collectors. By selecting the right pump and considering system design factors, you can ensure efficient and reliable performance from your solar hot water system.
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