Can geothermal provide hot water?

Water Heating

Geothermal heat pump (GHP) systems are designed to move heat from the ground into buildings for heating purposes. However, they can also be utilized to heat water, raising its temperature up to 125°F.

This dual function can be particularly advantageous when the cooling load is significant, allowing for more efficient use of the system by utilizing excess heat to satisfy hot water demands. By rejecting some of that heat back into the ground, the overall efficiency of the system can be enhanced, especially in environments where optimal temperature management is crucial.

Loop Pumping

The hydraulic design of the system and the choice of pumping equipment are critical factors that can influence the overall energy consumption of a GHP system. During transitional seasons like spring and fall, improperly designed pumping systems may consume more energy than the heat pumps themselves, leading to inefficient operation.

Ideally, an efficient system will use around 75 W/ton of cooling capacity; however, top-performing systems can reduce energy use to less than 50 W/ton. Achieving this involves minimizing friction losses, optimally selecting pumps to operate near their peak efficiency, and employing high-efficiency motors.

The use of variable frequency drives is essential for reducing pumping energy during non-peak loads. Furthermore, integrating normally closed valves with each heat pump allows for better management of fluid circulation, reducing unnecessary energy consumption.

Desuperheaters and Hot Water Systems

Installing a geothermal system can significantly contribute to your home's hot water supply. A cost-effective method of heating water using a GHP system is through a desuperheater, which captures excess heat from the heat pump's compressor.

This heated gas is then transferred to the water heater, providing a steady supply of hot water. In winter months, if the desuperheater doesn't suffice, a conventional water heater can still fulfill your hot water needs.

However, when the geothermal unit operates frequently, homeowners often find that they can meet their hot water demands at virtually no extra cost. Additionally, triple-function geothermal systems are gaining popularity as they combine heating, cooling, and hot water generation into one comprehensive and efficient solution.