A ground source heat pump (GSHP) is a type of HVAC (heating, ventilation, and air conditioning) system that uses the Earth’s natural heat to provide heating and cooling for a building. It works by using a network of pipes, called a ground loop, which is buried underground to exchange heat with the Earth.
The ground loop is filled with a fluid, usually water or a water and antifreeze mixture, which circulates through the pipes and absorbs or releases heat as needed. In the winter, the fluid absorbs heat from the ground and carries it to the heat pump, which then transfers it to the building. In the summer, the process is reversed, and the heat pump removes heat from the building and transfers it to the ground loop, effectively cooling the building.
GSHPs are highly efficient because they take advantage of the constant temperature of the Earth, which stays around 50-60°F (10-15°C) year-round at a depth of just a few feet. This is much cooler than the air temperature in the summer and much warmer than the air temperature in the winter, so the heat pump does not have to work as hard to transfer heat.
There are two main types of GSHPs: horizontal and vertical. Horizontal GSHPs are best for areas with a large amount of available land, as they require a longer ground loop. Vertical GSHPs are more compact and are suitable for smaller properties or areas with limited space.
One of the main benefits of GSHPs is their energy efficiency. Because they rely on the Earth’s natural heat, they use less electricity than traditional HVAC systems, which can result in significant energy savings. GSHPs are also environmentally friendly, as they do not produce any greenhouse gases or other harmful emissions.
However, GSHPs do have some drawbacks. They require a significant upfront investment, as the cost of installing a ground loop can be expensive. They also require regular maintenance to ensure that the system is operating at peak efficiency.
Overall, GSHPs are a reliable and efficient option for heating and cooling a building. While they may have a higher upfront cost, their energy savings and environmental benefits make them a worthwhile investment in the long run.
Types of ground source heat pump systems
There are several types of ground source heat pump systems available, each with its own set of advantages and disadvantages. Here are some common types of systems:
- Vertical closed loop system: This type of system uses vertical wells or boreholes that are typically 100-400 feet deep. Water or a water-antifreeze mixture is circulated through the wells to transfer heat to or from the ground. This type of system is most commonly used in areas with limited horizontal space, such as urban areas.
- Horizontal closed loop system: This type of system uses horizontal trenches or loops that are typically buried several feet below the ground. Water or a water-antifreeze mixture is circulated through the loops to transfer heat to or from the ground. This type of system is most commonly used in areas with plenty of horizontal space, such as rural areas.
- Pond/lake closed loop system: This type of system uses a body of water, such as a pond or lake, as the heat source or sink. A loop of piping is placed in the water, and a water-antifreeze mixture is circulated through the loop to transfer heat to or from the water. This type of system is most commonly used in areas with a natural body of water nearby.
- Open loop system: This type of system uses underground water sources, such as wells or springs, as the heat source or sink. Water is pumped directly from the ground source into the heat pump, and then returned to the ground once it has been heated or cooled. This type of system is less common due to the potential for contamination of the water source.
- Hybrid system: This type of system combines elements of two or more of the above systems, such as a horizontal closed loop system combined with a pond/lake closed loop system. Hybrid systems are often used to maximize the efficiency of the heat pump and take advantage of multiple heat sources or sinks.
How ground source heat pumps work
Ground source heat pumps (GSHPs) work by transferring heat between the ground and a building. In the winter, a GSHP can extract heat from the ground and use it to heat a building. In the summer, the GSHP can transfer heat from the building into the ground, effectively cooling the building.
GSHPs use a series of underground pipes, called a ground loop, to transfer heat to and from the ground. The ground loop is filled with a water-antifreeze mixture, which is circulated through the pipes by a pump. The heat pump, which is located inside the building, uses a refrigerant to absorb and release heat as it circulates through the system.
When the GSHP is in heating mode, the refrigerant absorbs heat from the ground loop and carries it inside the building. The heat is then transferred to the air or water being used for heating, and the refrigerant returns to the ground loop to absorb more heat.
When the GSHP is in cooling mode, the process is reversed. The refrigerant absorbs heat from the air or water inside the building and carries it outside to be released into the ground loop. The cooled refrigerant then returns to the building to absorb more heat. GSHPs are highly efficient and can provide a reliable and environmentally friendly source of heating and cooling for homes and buildings.