Ground Source Heat Pumps: Let the Earth Heat Your Home
Ground Source Heat Pumps
Everyone knows that the sun's rays are warm. What most people don't know is that the soil beneath our feet captures and stores some of that heat and that, depending on the soil type, the dirt and rock beneath the surface can become several degrees warmer as a result.
This page will attempt to describe how new technology is allowing us to extract that heat and use it to supplemnt the heating systems in our homes. By using a ground source heat pump, we are able to convert the warmth of the earth into useable heat for the buildings we inhabit, including schools, businesses and, of course, our homes.
Geothermal Heating is a term used to describe a wide range of systems. The following is an attempt to provide a “down to earth” explanation of Geo (earth) thermal (heat).
Geothermal systems extract very low temperature, but ever present heat from the earth and redistribute it to areas we wish to heat (and these systems can, when required, provide cooling as well). The earth’s surface is subject to temperature variations brought about by the seasonal swings, but these variations lessen as the depth of soil increases, and stabilize considerably > 3m/10 ft. At > 5m /16 ft, there is very little difference in temperature regardless of winter or summer conditions at the surface. This heat (or coolness) is what you experience when you enter deep caves, and is how the pioneers used root cellars to protect their food from cold and heat extremes.
While the act of extracting heat from the soil can and does lower the temperature of the soil over the course of the winter season, this heat is replenished during the summer months by natural solar energy (and also rejected heat from the geothermal system when operating as an air conditioner). Reports published by NASA say about 51% of incoming solar energy is absorbed by land and oceans.
A bit of history. In 1860, Lord Kelvin identified and determined ground temperature variations at given depths. In 1912, the Ground loop heat exchanger was first patented. In 1945, the first ground source heat pump was started
There are considered to be three main geothermal temperature types,
and these are:
• High ; > 302F/ 150C
• Medium ; 194F TO 302F = 90C to 150C
• Low ; < 194F /90C
Low is heat that can be extracted from shallow depths, and that can be
used directly by geothermal systems. These systems use work (Energy) to
transfer heat, though the energy used is less then the energy
transferred. This is referred to as the Coefficient of Performance. You
might notice system ratings with a C.O.P of 3, 4, or even 5. This means
that for a system rated with a C.O.P. of 3, for every unit of energy
(electricity) used, you would be extracting 2 units of heat from the
earth and you can heat and cool with the same unit
Geothermal energy systems using ground source heat pumps are becoming more popular as a means of heating and cooling homes. The basic principles on which these systems are based have been understood for hundreds of years. As new technology is developed and traditional heating costs skyrocket, there is a surge in interest in geothermal heat.
On this website you will find a series of articles related to all aspects of geothermal heating. We provide information about installation and operation of these systems as well as a variety other of other topics. In northern climates geothermal heat ground source heat pumps can be used to warm buildings in winter months. In hot weather the systems can be used to provide cooling. In addition a geothermal heat pump can very efficiently provide your home with the source of low-cost hot water. Some installations use a backup boiler which will require less energy and save significant amounts of money on energy bills for your home or business.
Some of the drawbacks of geothermal heating systems are the large upfront capital costs associated with installing the systems. Many governments offer financial assistance in the form of grants or loans or tax cuts which help consumers shoulder the cost of installation. Additionally, depending on the design of the installation, a large amount of land may be required. In particular this may cause problems for existing homes as landscaping may need to be disturbed in order to install the piping.
We believe that the advantages of geothermal heating systems
outweigh the disadvantages. If done properly, such a system can provide
years of reliable, efficient and low cost heating and cooling of your
home and offer an attractive return on investment. To learn more about
geothermal heating systems check out the other articles on this site.
Geothermal Systems can also be used to provide domestic hot water, heat a swimming pool, melt snow and ice etc. There are even systems in use today on dairy farms that cool fresh milk by drawing out the heat, and then redistribute it to heat buildings and homes! The many ways of drawing heat from the earth makes it possible to use this technology on almost any property to heat and cool our homes. There seems to be no end to what we can do with these systems when we put our minds to it.
We believe that the quest for ever more efficient and clean sources of energy is the repsonsible thing for every human to do. We all have to share this planet and literally every person alive is aware of the challenges faced by the earth and her inhabitants (us!!).
Additionally, nobody wants to be dependant on Big Oil or Big Coal for their survival. The cost of using these fossil fuels is skyrocketing, both in a financial sense as well as an environmental one.
We are not saying that Geothermal Heating Systems are the be-all that will save the planet. But we do believe that every home or business owner who explores new technologies is choosing a path that will result in energy efficient cost savings at some point.
The sun provides about 6000 times the total electrical energy required by the earth at any given moment. That vast solar energy is constantly replenishing the latent heat in the soil beneath our feet. A simple Geothermal heating system using a heat pump can collect that heat which we can then use instead of burning oil, gas or coal. It is our responsibility to investigate such things.
Maybe solar panels or windmills are more your style; that's OK too. Just because we are firm believers in the merits of Geothermal doesn't mean it is the only responsible choice. We encourage everyone to explore alternatives to traditional, fossil fuel based energy. It's the responsible thing to do.
The capital cost of a ground source heat pump will vary depending on a number of factors. The size and quality of construction of the dwelling, geography and soil types of the site, type of system, location within the home or business, and accessories, will all play a part it determining the cost of a GSHP.
The first step in determining the cost of the system is to evaluate your needs based on the expected heat loss of the dwelling or business. This is critical to ensuring that the system meets the heating and or cooling requirements of the building. It also ensures you don’t pay too much by purchasing an oversized system.
The first step in finding the size of the GSHP you will need is to do a heat loss calculation of the building. This can be done by assessing the buildings construction and looking at things like exposed wall area, level of insulation, area and type of windows, exposure to the sun, etc.
The results of the heat loss calculation will provide a number that represents watts, kilowatts or BTUs required to keep the building at a comfortable temperature during the most extreme weather swings in your area.
This stage of planning the system gives you enough information to select the size of the ground source heat pump you will require. This, along with the type of ground loop that will best suit the land your building sits on will give your contractors enough information to provide reasonably accurate cost estimates for you new ground source heat pump system.