What Is a Geothermal Heat Pump?
Geothermal heat pumps are heating and cooling systems that use the earth as its source of energy. Geothermal heat pumps get their name because “geo” means “earth” and “thermal” means “heat.”
Geothermal heat pumps are also called the ground source heat pump, GeoExchange, earth-coupled, water-source heat pumps that are considered extremely efficient renewable energy technology.
They are used for water heating, space heating, and cooling.
Benefits of Geothermal Heat Pump Systems
The benefits of geothermal heat pump systems include:
- Much lower operating costs than other systems. Up to 30 to 60 percent on your heating and 20 to 50 percent on your cooling will be saved with your geothermal heat pump than any conventional heating and cooling systems.
- Uses clean, renewable energy (the sun). There is no onsite combustion involved in the geothermal heat pump hence no emissions of carbon dioxide, carbon monoxide, or even other greenhouse gases.
- Can be installed in retrofit situations and new construction. However, retrofit situations are more expensive.
- Much quieter than other cooling systems. There is no outdoor compressor or fan that is very noisy. The indoor unit is quiet, and you might not even know it's on.
- Low maintenance and long-lived. The system requires minimal maintenance as it only has limited moving parts and is sheltered from outdoor elements. The indoor components usually last for about 25 years and more than 50 years for the ground loop.
Types of Geothermal Heat Pump Systems
Below are some types of geothermal heat pump systems.
Closed-Loop Systems
A closed-loop system is the most common, and it uses underground pipes that are filled with heat-transferring fluid.
Most closed-loop geothermal heat pumps buried in the ground or submerged in water circulate an antifreeze solution through a closed loop.
The heat is transferred between the refrigerant in the heat pump and the antifreeze solution in the closed-loop with the heat exchanger.
A direct exchange is a closed-loop system that does not use a heat exchanger. Instead, it pumps the refrigerant through a copper tubing buried in the ground in a vertical or horizontal configuration.
Horizontal
Installing the horizontal system is less expensive and is generally used when a large area of land is available.
It can be installed in depths as little as six feet underground.
Some of the most common layouts are either using two pipes, one buried at six feet while the other at four feet, or two pipes placed side-by-side in a two-foot wide trench at five feet in the ground.
Vertical
A vertical system requires more excavation but can be installed in areas where space is limited, like in schools or large commercial buildings.
The vertical system is also advisable for too shallow soil for trenching, thus minimizing the disturbance to existing landscaping. Holes for a vertical system are about 20 feet apart, and the depth is 100 to 400 feet.
Pond-Lake
A pond or lake system uses a loop that is submerged in water.
The water must be at least 20 feet deep to protect the pipes from freezing, and the loop bottom should be about 20 feet below the surface of the pond or lake.
A water source that reaches the minimum volume, quality, and depth requirements are where the coil should be placed.
Open-Loop Systems
Open-loop systems are most commonly used in areas where groundwater is abundant. A well or surface body is used as the heat exchange fluid that directly circulates through the geothermal heat pump system.
The water is pumped from the well and goes through the heat pump system before being returned to the same aquifer through a discharge well.
Hybrid Systems
Various geothermal resources or a combination of a geothermal resource with outdoor air are used in hybrid systems.
Hybrid approaches are particularly effective when cooling needs are remarkably larger than heating needs. The most common combination is a geothermal heat pump with an absorption chiller.
The absorption chiller uses a heat source to drive a cooling process instead of using electricity as conventional vapor-compression chillers.
Another option is solar panels which can be used with geothermal heat pump systems, providing both heating and cooling for the building.
Installing Geothermal Heat Pumps
Installers of geothermal heat pumps should be experienced and certified.
To properly install the piping, specialized technical knowledge and equipment are necessary.
The installation process of a geothermal heat pump system is similar to that of a conventional HVAC system. The main difference is the loop field, which can be installed in various ways depending on the type of system.
Operating and Maintaining Geothermal Heat Pumps
A key to the efficient operation of your heat pump is proper maintenance. In return, a well-maintained heat pump decreases your energy bills and increases the heat pump's lifespan.
The most major maintenance tasks are to keep the loop field clean and free of debris and to check the indoor air handler regularly.
Further, operate the system on the "auto" fan setting on the thermostat and consider installing multistage functions programmable thermostat suitable for a heat pump.
Thus, it is better if you have a professional technician service for your heat pump at least every year.
The following are what a technician can do:
Advantages of Geothermal Heat Pumps
The most significant advantage of a geothermal heat pump system includes:
- They basically have lower effective costs than ordinary systems, although their installation is quite expensive.
- The geothermal heat pump price ranges from $2500 at the rate per ton, so the three-ton average spent on installation would be $7500 compared to $4000 for traditional air conditioners. But, these systems can save energy on a yearly basis from 40 to 70 percent.
- Compared to traditional air conditioning systems, they are more durable, and the span of effectivity is about 50 years. They don't necessarily need maintenance or negligible maintenance, but they guarantee that they will usually last 25 to 50 years.
- They are not noisy.
- No combustion is present in these systems, and the discharge of conservatory gasses is being cut down, which makes them environment-friendly. Thus, they decrease the emission of gasses equivalent to the amount reduced by 750 trees.
- They don't cause aesthetic degradation to exterior homes since the systems are all underground and the pipes are buried.
- They have been used in cooling or heating water by the use of de-super heaters.
- Also used to heat floors or used for sunny floor covering.
- They employ ductwork to maintain humidity and maintain comfortable temperatures all around the year.
Key Takeaways
A geothermal heat pump is a type of heating and cooling system that uses the constant temperature of the earth to supply cooling, heating, and hot water for a home or office building.
There are four main types of geothermal heat pump systems: closed-loop, horizontal, vertical, and pond/lake.
The installation process of a geothermal heat pump system is similar to that of a conventional HVAC system.
Operating and maintaining a geothermal heat pump system properly is crucial to its efficiency and lifespan.
Advantages of geothermal heat pumps include lower energy costs, increased comfort levels, longer equipment life spans, and reduced maintenance requirements.
FAQs
1. What is a geothermal heat pump?
A geothermal heat pump is also called the ground source heat pump, GeoExchange, earth-coupled, water-source heat pump that is considered extremely efficient renewable energy technology. It is utilized for water heating, space heating, and cooling. It also aims to move existing heat from the ground in your home.
2. How do geothermal systems work?
A geothermal system comprises a heat pump, an underground loop system, and a desuperheater. The heat is moved from the ground to the building in winter and from the building to the ground in summer through the heat pump.
3. What are the benefits of geothermal systems?
The benefits of geothermal heat pump systems include lower energy costs, increased comfort levels, longer equipment life spans, and reduced maintenance requirements.
4. Do geothermal heat pumps use electricity?
Absolutely, yes. When there is a power outage, they will not work unless there is a backup generator or battery storage system.
5. How long do geothermal heat pumps last?
Typically, geothermal heat lasts 20 to 25 years.
