Ground source heat pumps, or geothermal heat pumps, are systems that use the groundwater or surface water as a water source or heat source. They are becoming a more popular sustainable design feature because they can use anywhere from 25 percent to 50 percent less electricity than traditional heating or cooling systems.
In relation to air-source heat pumps, the benefits of geothermal heat pumps include:
● Require less electricity to operate
● Are longer lasting
● Require little maintenance
● Don’t depend on outside temperatures
Heat pumps work by collecting or removing the energy (heat) from the water. In the winter, the pump removes the head from the pipes and transfers it into the building. In the summer, the process is reversed. Therefore, they can be used for both heating and cooling a building—a popular feature in almost any climate.
Geothermal heat pumps are able to be installed in most places in the United States, however, various factors including location play a major role in the type of heat pump to use. These include the ground area available for development, natural gas lines, the thermal conductivity of the soil, ground temperatures, local ground water availability, or access to open water sources will be factored into the decision-making process.
Groundwater Heat Pump Systems
In all heat pump systems, the energy (heat) in the ground must be absorbed into an existing fluid before being transported to the building. This system uses well or surface body water as the “heat exchange fluid.” Once it has circulated through the entire system, the water then returns to the ground through the well, a recharge well, or surface discharge. This tends to be the most widely used heat pump system.
Ground-Coupled Heat Pump Systems
This is also known as the “closed-loop” heat pump, and is one of the more complex heat pump systems. It consists of a vapor compression cycle coupled with a heat exchanger, and can be either a water-to-air pump or a direct expansion heat pump. Either a vertical or horizontal well will need to be dug ranging anywhere from 50-600 foot boreholes or 4-6 foot trenches. These systems aren’t as energy efficient as other systems because they rely greatly on seasonal soil fluctuations and higher pumping energy requirements.
Surface Water Heat Pump Systems
This type of heat pump can either be a closed-loop system (similar to ground-coupled heat pumps) or a open-loop system (similar to groundwater heat pumps). With closed-loop systems, the piping loops are placed in a lake, river, or other open body of water, which allows the pump to circulate water through the heat exchanger and transfer the heat to and from the body of water. With open-loop systems are less complex, in that lake water can be directly pumped to the heat pumps.
Depending on the size of your facility, Gausman & Moore’s engineers can run a thermal conductivity test to determine the amount of heat available in the area. This will help determine if installing a geothermal heat pump system is the best option for your location. Visit our Mechanical Engineering page or contact us at 651-639-9606 for more information about our heat pump systems and installation.