A Deep Dive Into Geothermal Heat Pumps & Their Functioning

Photo of author

By Debarghya Roy

Geothermal heat pumps are a great way to save energy. They use the earth’s temperature to heat and cool buildings.

How Do Geothermal Heat Pumps Work?


To understand how geothermal heat pumps work, you need to explore the ground heat exchange and the heat pump unit. 

how does a geothermal heat pump work

The ground heat exchange is crucial to these systems, as it enables the transfer of heat energy from the earth to the heat pump unit. The heat pump unit then uses this energy to provide heating and cooling for your home.

Ground Heat Exchanger

Ground Temperature Exchange is an essential part of Geothermal Heat Pumps

This strategy uses the Earth’s constant temperature to add or remove heat from/to a building. 

It involves drilling boreholes and putting in U-shaped pipes. Heat exchange happens between the fluid and the soil around it.

Note that temperatures depend on the climate, soil type, and depth.

Also, this method reduces energy consumption by up to 70% compared to traditional HVAC systems. 

The US Department of Energy says that geothermal heat pumps can lessen residential heating and cooling costs by up to 60%

Check out the Soil Temperature Profile in Fahrenheit:

Depth (ft)Temperature
0-1050-60
10-2060-65
20-3065-70
30-4070-75

Closed-loop systems

Closed-loop geothermal systems are essential for geothermal heat pumps. Water or a mix of anti-freeze and water is circulated through pipes in the ground or underwater. 

It extracts the heat from the earth and transfers it to the heat pump, which converts it to warm air.

Closed-loop systems don’t depend on outdoor temperatures. A study from the U.S Department of Energy says households can save $750 annually and reduce energy usage by 45% by using geothermal heat pumps over traditional systems.

This system has three types: Vertical, Horizontal and Pond/Lake. 

Here are the details in a table:

Sub-TypeLocationDepth/DistanceSuitable for
VerticalDeep wells100-400ftBig buildings with small land
HorizontalUnderground trenches6-8ftLarger land areas
Pond/LakeCoils in a lake or pond8ft below surfaceNear water

Open-loop systems

  • Open-loop systems for geothermal heat pumps involve extracting groundwater or well water to use as a heat source or sink.
  • Circulate the water through the system and return it to the ground – the water temperature should remain constant and reliable.
  • It’s important to remember that groundwater may contain impurities. This can cause scale buildup and corrosion in the heat pump system. 
  • Check if there is sufficient water available, too. Otherwise, this method may not be suitable for large-scale heating and cooling needs.
  • Regular maintenance checks are a must for open-loop systems. Both the heat pump and groundwater supply source need to be checked.

Heat Pump unit

The mechanism of a Heat Transferring Unit is quite intriguing. It moves heat energy from one place to another, making it possible to control room temperature.

Let’s look at a table that explains its components.

ComponentFunction
CompressorPressurizes refrigerant
EvaporatorExtracts heat from inside
CondenserReleases extracted heat outside
Expansion ValveReduces pressure and cools refrigerant

Compressor

A key part of the geothermal heat pump system is the compression equipment. Its main job is to pressurize and circulate a refrigerant, transferring heat between the ground loop and the air distribution system. 

It is responsible for pumping heat through the entire geothermal system.

This equipment works with either a scroll compressor, a rotary compressor, or reciprocating piston compressors. They offer enhanced durability.

When energy needs are high, like during peak loads or bad weather, the compressor helps to provide the extra energy needed.

Check out this table to understand more:

TypeDescription
Scroll compressorQuiet and efficientFewer moving parts
Rotary compressorSmall, compactEasy to maintain
Reciprocating piston compressorDurableLong lifespan

Refrigerant

A refrigerant is key for geothermal heat pumps to work. It transfers heat between the ground and your house in a closed loop. 

It’s good to use refrigerants with low GWP to help the environment and get an efficient system.

Check out the table for details on different refrigerants.

RefrigerantEnvironmental Effect
R-410ACommonly used with mild environmental effect
R-404AHas moderate effect and potential for ozone depletion
R-290Has low GWP and mild effect

Heat exchanger

To exchange heat, there is a key element in the geothermal heat pump system. It helps to move and balance the heat between the refrigerant and the ground. 

The heat exchanger location depends on whether it is vertical or horizontal. Also, the size and type depend on how much heat is expected from one place compared to another.

People have used natural hot springs for centuries. Now, with science and technology, these thermal wells can provide lots of clean energy at low costs.

The table below shows some info about this section of the system.

ElementLocationSize and type
Heat ExchangerVertical or HorizontalDepends on expected heat

Expansion valve

The Expansion Valve is a key part of geothermal heat pumps. It manages refrigerant flow from the condenser to the evaporator, and helps control temperature. 

The Valve type depends on system configuration and manufacturer. 

Change it regularly, and hire a professional for maintenance, like cleaning or replacing filters. 

Geothermal heat pumps give you free AC/heating without the guilt of leaving windows open all night.

The following is Table contains information on expansion valve specifications:

TypeSizeFunctionInlet PressureOutlet PressureStart TemperatureEnd Temperature
Thermostatic1-1/8 inchMaintains constant pressure35 PSI50 PSI40°F60°F
Electronic2 inchesVaries refrigerant flow40 PSI55 PSI20°F70°F
Manual3/4 inchControlled by manual adjustment30 PSI45 PSI50°F80°F

Benefits of Using Geothermal Heat Pumps


To reap the benefits of using geothermal heat pumps with regard to energy efficiency, cost savings, and environmental benefits, this section analyzes how it works. 


Energy Efficiency

  • Geothermal heat pumps are a win-win: planet preservation and cost savings. They use stored solar energy from the earth to heat and cool buildings. 
  • They’re very energy efficient, saving up to 70% on heating and 50% on cooling costs. 
  • They don’t combust fuel like traditional HVACs, making them more sustainable.
  • They require almost no maintenance once installed. With fewer parts, they’re reliable and less expensive to maintain. 
  • Upgrade insulation and seal air leaks. Proper installation will optimize performance and decrease maintenance costs. Even in extreme weather, geothermal systems will work well.

Energy Efficiency

Geothermal heat pumps are the ultimate two-for-one deal. Not only are they environmentally friendly, but they also offer economic benefits.

Cost savings can be found in various areas, such as:

  • Lower utility bills due to renewable energy;
  • A longer lifespan than traditional HVAC systems; and
  • Increased property value due to energy-efficient features.

Customize the geothermal heat pump system to your needs. Research government incentives to offset expenses. Plus, hire an experienced contractor for proper installation and regular maintenance. You’ll save long-term and reduce your carbon footprint!

Environmental Benefits

This eco-friendly heating and cooling system offers plenty of benefits.

  1. It emits fewer greenhouse gasses, shrinking your carbon footprint.
  2. No need for fossil fuels, just use the Earth’s natural heat.

Geothermal systems produce low noise levels compared to conventional ones. They also last longer and require less maintenance – meaning fewer resources used for repairs and replacements.

Your property will be worth more in the long run too, as energy-efficient homes are increasingly sought after. 

With geothermal, you can protect the environment while keeping your home comfortable.

For even more energy and environmental savings, make sure your system is well maintained. 

Consult experts before installation for advice on how to use renewable energy sources, like solar panels, with your geothermal system. 

Benefits of Geothermal Heat Pumps in Homes and Businesses


Geothermal heat pumps are an awesome way to warm and chill homes and businesses. They rely on renewable energy from the earth, making them eco-friendly. 

Here are some of their perks:

  • Energy savings: Geothermal heat pumps use less energy than traditional heating or cooling systems – this means lower electricity bills.
  • Durability: Geothermal systems have fewer parts than regular HVAC systems, which cuts down on expensive repairs.
  • Comfort: These systems provide even temperatures throughout a building, getting rid of hot or cold spots.
  • Noise reduction: Geothermal systems operate quietly in comparison to traditional HVAC systems.
  • Long lifespan: With proper maintenance, geothermal systems can last 25 years or more.

Installation Process of Geothermal Heat Pumps


To ensure a successful installation process of your geothermal heat pumps, a thorough site assessment is necessary. 

With site assessment in mind along with the installation process, you can ensure that your geothermal system is set up for optimal performance.

Site Assessment

For successful and cost-effective geothermal heat pump installation, an in-depth site evaluation is essential. 

Preparing and assessing the site enables Heat Pump installation to be more successful.

Gather data on the Site Assessment table. Such as: size and layout of the property, soil conductivity analysis, water source availability, local building codes and regulations, and access to energy grids.

Installation Process

Going green with a geothermal heat pump is a popular choice. Installation requires steps that must be taken with care and expertise.

  1. Site Preparation – Clear the area, and dig trenches or boreholes.
  2. Piping Installation – Place the piping system in the prepared area.
  3. Unit Installation – Connect the heat pump to power and water supplies. Plus, sometimes vertical drilling is needed for space or soil limitations.

HeatSpring reported that electric costs can reduce by up to 70% after installation. Going underground for the vertical loop installation yields eco-friendly benefits!

Vertical Loop Installation

  • Vertical loop placement is key for successful geothermal heat pump installation. Boreholes are typically 150-300ft deep and diameters vary based on specific project needs. 
  • Factors like site condition, soil type and drilling method must be taken into account. A professional engineer should conduct a feasibility study prior to installation.
  • Proper vertical loop installation is essential for optimal performance, energy efficiency and longevity of geothermal heat pumps. 

Horizontal Loop Installation

Horizontal Ground Loop Installation is an essential part of setting up geothermal heat pumps. Here’s how to get it right:

StepsDescription
Dig The Area
Dig the area in a way that the horizontal loops fit in, following the design plan.
Place Pipe Loops

Place pipe loops in trenches, pre-drilled holes, or excavated bore/holes. Connect them properly.
Pack Buried Pipe
Pack the buried pipe with high-density material to maintain conductivity between the ground and loop.
Pressure Test
Pressure test the horizontal ground loop system with air before burying it to make sure there are no leaks.
Fill The Area
Backfill the area around the horizontal ground loop with caution – avoid damaging any components.

Pond/Lake Installation

A geothermal heat pump system can be installed in multiple ways, including using a pond or lake. 

For the ‘Pond/Lake Installation’ option, pipes must be submerged into the water to draw out its heat. 

Here’s a 5-step guide:

  1. Check the size and depth of the water source to determine if it can meet your HVAC needs.
  2. Install an HDPE pipe system with loops for water circulation.
  3. Sink the pipes about 8 feet deep into the pond/lake bed.
  4. Connect the underground pipes to the geothermal unit components like compressors and evaporators.
  5. Perform maintenance, clean any debris from the pipes, check for leaks and make sure water is flowing properly.

Open-Loop Installation

Installing an open-loop geothermal heat pump system requires five steps:

  1. Pick a water source with the correct flow rates and temperatures.
  2. Drill wells with casing to prevent contamination.
  3. Connect inlet and outlet pipes between the heat pump and the well.
  4. Install a filter to sieve out particles before they enter the unit.
  5. Put the injection wells in the right place to return unused water.

Maintenance of Geothermal Heat Pumps


To maintain the efficiency of your geothermal heat pump, implement a regular inspection routine for all key components. 

These sub-sections on Regular Inspections, Filter Replacement, and Professional Servicing are significant for keeping your geothermal heat pump in good condition.

Regular Inspections

Regular check-ups are vital for the proper functioning of geothermal heat pumps. 

A professional HVAC technician should look over the system’s components to guarantee everything is in working order. 

Ignoring inspections can result in poor performance, operational inefficiencies, and possible breakdowns.

To keep the system running smoothly, six key points should be checked frequently:

  • Leakage in the heat exchanger
  • Electrical connections and controls
  • Air filters (cleaning & replacing)
  • Refrigerant levels and pressures
  • Fittings, nuts, bolts, and screws (tightening)
  • Thermostat (functioning correctly)

These maintenance tasks can lengthen the lifespan of a geothermal system. They also detect any potential issues before they become expensive.

Moreover, inspection frequency may vary due to factors such as usage and location. For instance, hotter climates likely need more regular check-ups because of higher system usage.

Filter Replacement

For the best performance and to avoid damage to the heat pump, replace the filter regularly. 

Here are five tips to follow for effective filter replacement:

  1. Look up the manufacturer’s instructions for filter type, replacement frequency, and installation process.
  2. Cut power to the unit and disconnect it from its energy source before starting.
  3. Take out the old filter and get rid of it in a proper way.
  4. Eliminate any remaining waste or buildup inside the housing before you insert the new filter.
  5. Put in the new filter as per manufacturer instructions and turn the power back on.

It’s important to remember that clogged or incorrect filters can lower system efficiency by up to 25%. So, maintaining and replacing them can better system performance and durability.

For proper filter work, routinely check for ductwork leaks. Leaks can cause air contaminants to miss the filters, leading to poor indoor air quality.

As per Energy Star, replacing a grimy, blocked air filter with a clean one can reduce your cooling equipment’s energy consumption by 5-15%

Professional Servicing

Geothermal heat pumps need regular professional maintenance to keep working well. A certified technician can extend its lifespan, reduce energy, and prevent big breakdowns.

A thorough service program includes changing or cleaning air filters, examining refrigerant levels, checking ductwork, and flushing draining pans and lines for sludge build-up. Professional Servicing is key to finding any leaks or broken parts that could hurt efficiency.

Every six months it’s important to get a tune-up. This helps identify possible problems before they get serious. With proper care from a qualified technician, geothermal systems can remain efficient for decades.

Conclusion


Geothermal heat pumps are the most efficient renewable option for heating and cooling. Using it in a proper way helps in saving on energy and utility bills.

Frequently Asked Questions


What is a geothermal heat pump?

A geothermal heat pump is a heating and cooling system that uses the constant temperature of the earth to regulate the temperature inside a building. It exchanges heat with the ground or groundwater to heat or cool the building as needed.

How does a geothermal heat pump work?

A geothermal heat pump uses a loop of pipes containing a fluid, typically water or refrigerant. 

  • The fluid is circulated through the pipes and absorbs heat from the ground in winter, while in summer it releases heat into the ground. 
  • The heat from the fluid is then transferred to a compressor, which amplifies the heat and distributes it throughout the building using a fan or ductwork.

What are the benefits of using a geothermal heat pump?

Geothermal heat pumps are highly efficient and can save up to 60% on heating and cooling costs compared to traditional HVAC systems. They’re also eco-friendly, as they use renewable energy from the ground, emit no greenhouse gases, and require very little maintenance.

How much does it cost to install a geothermal heat pump?

The cost of installing a geothermal heat pump varies depending on the size of the system, the complexity of the installation, and the location. However, on average, a geothermal heat pump installation can cost between $10,000 and $30,000.

How long do geothermal heat pumps last?

Geothermal heat pumps have a lifespan of between 25 and 50 years, which is considerably longer than traditional HVAC systems. They also have fewer moving parts and require less maintenance, which helps to extend their lifespan.

Are there any incentives available for installing a geothermal heat pump?

There are several incentives available for homeowners who install geothermal heat pumps. These include federal tax credits, state and local incentives, and utility company rebates. These incentives can significantly reduce the cost of installation and make geothermal heat pumps more affordable.

Heat Pump