Maximising the Efficiency of a Geothermal Heat Pump

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heat pump system

One of the most efficient ways to keep your home at a comfortable temperature all year round is geothermal heating and cooling. A geothermal heat pump is a heating and cooling unit installed in a basement of a home and connected to an array of underground coils to make indoor temperature on the desired level. When choosing and installing a geothermal heat pump (GHP) in a new home, consider the heating and cooling efficiency, the system economics and the characteristics of the property. Still, there are some tricks to maximize the GHP efficiency.

heat pump system
Heating and cooling efficiency
All ground-source and water-source heat pumps have a coefficient of performance (COP), which is the ratio of heat provided in Btu per Btu (British thermal unit) of energy input. Their cooling efficiency, on the other hand, is indicated by the Energy Efficiency Ratio (EER) which is the ratio of the heat removed in Btu per hour to the watts of electricity required to run the unit. Always look for systems with the Energy Star label, which indicates that the unit meets the Energy Star criteria.
Increase the ground loop
The ground loop is the part of the system which your heat pumps use to harvest heat for your home. In the winter, a larger ground loop will keep a higher overall temperature, which means that the pump will work less to heat up the incoming fluid. Pump installers sometimes make the ground loop as small as possible to minimize the initial costs. However, keep in mind that spending a little more in the beginning will make your unit more effective for many years to come.


Go for an open water well loop
Open water well systems maintain a higher temperature than a ground loop. So, if you have enough flow, consider building a two well system as your energy supply source. In case you choose an open loop route for your heat pump, make sure your installer has calculated the effect of the submersible pump on the system’s overall efficiency.
Turn down the buffer tank temperature
A buffer tank is an element that comes between your radiant in-floor heating and your water heat pump. Most installers would normally set the buffer tank between 47ºC and 48ºC, but in reality you don’t need your buffer tank set that high. Turn in down to 29ºC, as it is more than enough to keep your home comfortable through all the seasons.


Clean the heat exchanger
If your pump is using an open loop supply, you may need to clean the heat exchanger from time to time. Unlike a closed loop, an open loop system uses well water that may be contaminated. These contaminants can build a layer of scale on the heat exchanger walls over time. The scale reduces heat transfer and consequently your pump’s efficiency. Occasional cleaning will keep the system free of organic matter and debris.

 

Why choose a GHP system?
Low maintenance costs and a long life span of the system are only some of the benefits of geothermal heating. A GHP unit uses 25% to 50% less electricity than conventional cooling systems. In other words, a GHP unit uses one unit of electricity to move three units of heat from the earth. According to the U.S. Environmental Protection Agency (EPA) geothermal heat pumps can reduce energy consumption and emissions up to 72% compared with electric resistance heating.
If you are determined to win the energy efficiency battle, purchasing a geothermal heat pump is a very viable option to consider. However, keep in mind that the pump is only the heart. It needs other energy saving upgrades such as insulation, window retrofits and weather stripping to maximize its potential to the full.

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