Learn About How Geothermal Works!
About Geothermal Heating & Cooling
Geothermal Energy is heat (thermal) derived from the earth (geo). It is the thermal energy contained in the rock and fluid (that fills the fractures and pores within the rock) in the earth's crust. While temperatures above ground change a lot from day to day and season to season, temperatures 20 feet below the Earth's surface hold nearly constant between 50° and 60°F. For most areas, this means that soil temperatures are usually warmer than the air in winter and cooler than the air in summer. Geothermal heat pumps use the Earth's constant temperatures to heat and cool buildings. They transfer heat from the ground (or water) into buildings in winter and reverse the process in the summer.
Geothermal Solutions Are Green & Cost Effective
The current production of geothermal energy from all uses places third among renewables, following hydroelectricity and biomass, and ahead of solar and wind. According to the U.S. Environmental Protection Agency (EPA), geothermal heat pumps are the most energy efficient, environmentally clean, and cost effective systems for temperature control. Ground-source heat pumps use the earth or groundwater as a heat source in winter and a heat sink in summer. Using resource temperatures of 4°C (40°F) to 38°C (100°F), the heat pump, a device which moves heat from one place to another, transfers heat from the soil to the house in winter and from the house to the soil in summer.
Different Types of Installations
Geothermal Heating and Cooling - How it works: Geothermal Energy is heat (thermal) derived from the earth (geo). It is the thermal energy contained in the rock and fluid (that fills the fractures and pores within the rock) in the earth's crust. It simply takes advantage of the earth's ability to store heat.
Water circulates through a loop of pipe buried in the ground and draws off the free heat from the earth. The heat is then concentrated by the geothermal heat pump through the refrigeration process and is released into your home through the blower or radiant floor heat system. In the summer, the process is reversed and heat is removed from your home and put back into the earth. The loop that collects the heat from the earth can take a variety of shapes depending on the location. All of these loop types serve one purpose: To collect free heat from the earth and deliver it to the heat pump.
About Geothermal Earth Loops
There are four basic types of ground loop systems, that can be divided into two basic categories, closed loops and open loops. All of these approaches can be used for residential and commercial building applications. If this guide isn't enough to answer ALL of your questions, please don't be afraid to contact us and we'll be glad to answer any of your questions.
For closed loop systems, an antifreeze solution is circulated through plastic pipes buried beneath the earth's surface. During the winter, the fluid collects heat from the earth and carries it through the system and into the building. During the summer, the system reverses itself to cool the building by removing heat from the building, carrying it through the system and releasing it in the ground. Most systems are also equipped with a device to divert some of the energy towards the creation of free hot water in the summer and provides very inexpensive hot water in the winter.
Open loop systems operate on the same principle as closed loop systems and can be installed where an adequate supply of suitable water is available and open discharge is feasible. Benefits similar to the closed loop system are obtained.
This type of installation is generally most cost-effective for residential installations, particularly for new construction where sufficient land is available. It requires a large pit to be excavated about 8 feet deep and about 400 foot long. A slinky loop method of looping pipe allows for a much shorter trench, which may cut down on installation costs and makes horizontal installation possible in areas it would not be with conventional horizontal applications.
Another variation on the horizontal loop is the horizontal bore system. This uses a boring machine that bores horizontally 12-20 feet below the surface, providing for excellent loop performance while leaving the existing landscaping undisturbed. This system is often used in retrofit applications and is typically a little more expensive than a trench system, but less expensive than a vertical loop system.
Where the land area required for horizontal loops is not available or otherwise prohibitive, vertical loops are an excellent choice. Vertical loops also minimize the disturbance to existing landscaping. For a vertical system, holes (approximately four inches in diameter) are drilled about 12-20 feet apart and 100-400 feet deep. Into these holes go two pipes that are connected at the bottom with a U-bend to form a loop. The vertical loops are connected with horizontal pipe (i.e., manifold), placed in trenches, and connected to the heat pump in the building.
If the site has an adequate water body, this may be the lowest cost option. A supply line pipe is run underground from the building to the water and coiled into circles at least eight feet under the surface to prevent freezing. The coils should only be placed in a water source that meets minimum volume, depth, and quality criteria.
This type of system, also called "pump and dump," uses well water that circulates directly through the heat pump system. Once it has circulated through the system, the water is discharged into a local stream or pond. This option is obviously practical only where there is an adequate supply of relatively clean water, and all local codes and regulations regarding groundwater discharge are met.
About Ground Source Heat Pumps
Ground Source Heat Pumps offer great benefits:
- Your system can provide forced air heating and cooling and/or radiant heating system
- Some can save you up to 50% on your water-heating bill by using a preheat tank for hot water
- The earth loop is constructed of high grade components that are buried in the ground and usually carry a 75 year warranty.
- Takes up about the same space as a traditional heating/cooling unit
- Cuts energy consumption by 75% and reduces maintenance costs
- Provides consistent temperature throughout the home, eliminating the hot and cold spots common with other systems
- No outside unit to cause a noisy, unpleasant environment outside the home
- No exposed equipment outdoors; children or pets cannot injure themselves or damage exterior units
- No open flame, carbon monoxide, carbon dioxide, flammable fuel or potentially dangerous fuel storage tanks
Ground Source Heat Pumps are environmentally friendly:
- Conserve natural resources by providing climate control efficiently and thus lowering emissions
- Minimize ozone layer destruction by using factory-sealed refrigeration systems, which will seldom or never have to be recharged
- Uses underground loops to transfer heat, with no external venting or air pollution
- Reduces carbon footprint
Ground Source Heat Pumps offer great savings:
- The most efficient residential heating and cooling systems available today (according to EPA)
- By using the earth energy to provide 70% of your home's heating needs, most systems have efficiencies of 350%
- Cooling efficiencies are 20% to 40% higher than available air conditioners
- Save money in operating and maintenance costs
- Investments recouped in only a few years
- Positive cash flow; energy savings usually exceed the cost of the system
- Some utilities offer rebates or incentives to their customers who purchase GSHPs
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