An Introduction to Geothermal Heating and Geothermal Pumps
How does a geothermal heat pump work?
When you talk about a geothermal pump you are usually discussing some sort of heating and cooling system. The
modern geothermal pump, or GHP, relies on the constant temperature of the earth (only a few feet below the surface)
as a sort of “exchange medium”. During cooler weather the GHP will pull the heat from the ground – which retains a
constant temperature between 45°F to 75°F - and carry it indoors via a specially designed system. During the warmer
months it can also reverse the process and distribute the warmer air back into the ground.
How It All Works
Before we discuss how the geothermal pump works, we need to look at a geothermal heating system. It is
interesting to note that the modern designs have been in use since the 1940s, but have only really “taken off” in
terms of installation in homes over the past few decades.
A geothermal heating (and cooling) system is actually very basic and easy to understand. It helps to consider it by
its other name which is a “ground source heating system”. This means that the heat is pulled from the ground via a
cleverly designed “closed loop” system of pipes that are buried in the ground beneath a home or property. These
pipes contain water or a refrigerant that is circulated through, and which pull the existing heat from, their
surroundings. The heat is circulated back up through the pipes where the warm liquid from the ground is passed in
front of a fan or blower unit.
The fluid remains contained within the pipes at all times (hence the “closed loop) and the fan simply blows air
around the pipes to force the heat into the ductwork. This is an overly simplified explanation of how geothermal
works, but it does help to give you a good idea of the total absence of traditional energy supplies for a large
portion of the system.
The GHP distributes the heated air via a blower or fan. This is where there is a need for an electrically driven
compressor and “heat exchanger” to enter into the proverbial equation. Obviously, this is not going to be driven by
a renewable resource, and this means that a GHP system is not actually one hundred percent renewable energy.
The thing about any GHP is that it is a heat pump, which means that it is always going to be able to heat and cool,
and can even supply the home or structure with hot water if equipped with a “desuperheater”.
Because the idea of renewable resources is so important and of interest to so many, there are now more models of
GHPs available. Systems are also incorporating two-speed compressors and fans of variable speeds and power to allow
for greater home comfort and even for energy savings.
A GHP is known to be extremely quiet and efficient, and to require little to no maintenance when designed and
installed by knowledgeable professionals. Though they can be costly to install, they will enjoy a “payback” in as
little as five to ten years, with a life span of more than 25 – which is superior to traditional air-source/fossil
What are the advantages of using a geothermal system? There are many, and they include:
Financial Savings – Not only does the owner of a GHP (geothermal heating pump) get to enjoy reduced costs on things
like home fuel oil, but they also reduce general operating costs by around 80%. This is because the systems demand
far less energy IN GENERAL thanks to their efficiency and their use of the earth instead of the air for the
creation of heat;
Environmentally Friendly – Clearly, it is a huge advantage to use a system of
renewable energy to heat and cool your home, and to also create domestic hot water supplies. Because there is no
need to burn up a fuel in order to create heat, a GHP system is going to be almost pollution free (with the
exception of the electrical supplies used to power the pump). This means that a homeowner using geothermal creates
very little pollution and consumes almost no fossil fuels or energy to operate the system;
Durability – The installation of a GHP system means the use of piping below the
ground, and qualified installers will fuse piping together with an approach that is stronger than the pipe itself.
This means that geothermal systems are incredibly strong, demand very little maintenance over their 25 to 50 year
life spans, and use so few mechanical components as to be one of the most user-friendly types of heating and
cooling available; and
Affordability – Though a geothermal system does require drilling for the
installation of the pipes, most of the systems have a complete “payback” (meaning the time when the system has
saved so much that it has paid for itself) of ten to fifteen years, which is unprecedented in the world of home
heating and cooling.
Disadvantages of Geothermal Heat Pumps
There are not many disadvantages to the use of a home GHP system, but they can include:
Limited Availability – There are not a lot of installers yet offering their services for home geothermal
installations and systems. This means that it can be difficult to get one for a home and just as difficult to get
service on it; and
Costly to Install – The drilling and special skills/knowledge necessary for an installation can make them quite
costly, though we already mentioned that most systems pay for themselves in a decade.
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