Blue’s Clues: Emma Downing, Cody Barnett, Sam Tarnowski Geothermal Heating Blue’s Clues: Emma Downing, Cody Barnett, Sam Tarnowski

What is it? Geothermal heat pumps use the ground temperature, which can range from 45˚F to 75˚F. The ground temperature is warmer than the surface air during the winter and cooler during the summer. The heat pumps are designed to heat, cool, and can be used to supply a house with hot water. Source: 1

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Types of geothermal heat pump systems Closed-Loop Systems Horizontal Systems Vertical Systems Pond/ Lake Systems Open Loop Systems Hybrid Systems Source 11

Closed-Loop systems These circulate a solution through plastic tubing that is buried in the ground or submerged in water. Heat is transferred between the refrigerant in the heat pump and the antifreeze solution in a closed loop. The following slides are examples of closed loop systems. Source 11 Source 2

Horizontal systems This is mainly used for residential properties, as it requires a sizable amount of land. Trenches at least four feet deep must be dug, with coils of piping in lines side by side. Source 11 Source 3

Vertical systems This style of installation is used for commercial buildings and spaces where the area of land available for the pipes is small. Holes are drilled 20 feet apart and from 100 to 400 feet deep. These holes are connected by alternating U-bends at the top and bottom. Source 11

Pond/lake systems This is generally the least expensive option, although it has some of the strictest criteria, with restrictions on a minimum volume, depth, and quality criteria. Coils are submerged at least eight feet under the surface to prevent freezing. This avoids the costs of digging appropriate trenches while still accessing the moderate temperatures. Source 11 Source 3

Open-loop systems This system utilizes a well or body of water as the heat exchange fluid that flows through the GHP system. Once used, the water returns to the body of water through a well or recharge well. This is only a possibility with a large enough supply of clean water, and groundwater regulations are strictly enforced. Source 11 Source 4

Hybrid systems Hybrid systems combine geothermal resources, such as the ground water, the outdoor air, among others. One of the most common approaches is a cooling tower, or a column well. A column well is a system containing deep vertical wells. Source 11 Source 9

Benefits of geothermal heating Geothermal heating in homes is very cost effective. While the initial price may be higher than other forms of heating/cooling, the high efficiency leads to major savings in the long run. GHP systems are durable and highly reliable. The under-ground piping used typically lasts 25 to 50 years and the GHPs themselves often last around 20 years. Geothermal heating systems are very low maintenance. If properly installed, the underground components do not need to be worried about. GHPs are very efficient and require a lot less energy to maintain comfortable temperatures. They also result in a decrease of emissions compared to other forms of heating/cooling systems.

Where is it used? Geothermal energy is being used to generate power in over 20 countries around the world, including Iceland, the United States, Italy, France, New Zealand, Mexico, Nicaragua, Kenya, Costa Rica, Russia, Philippines, Indonesia, People's Republic of China and Japan. The United States is the world’s largest producer of geothermal energy. Most of the geothermal power plants in the United States are located in the west and in Hawaii. California generates the most electricity from geothermal energy. Source 13 Source 5

Research institutions Idaho National Laboratory- Investigates geothermal resource technologies for both direct use and electricity generation Kansas State University- Modeling flow in fractured rocks for the development of reinjection systems for geothermal reservoirs Oklahoma State University- Develops geothermal heat pump systems and ground loop heat exchanger technology Source 10

Implementation Reykjavik, Iceland gets 90% of its heat for homes and public buildings by directing hot water from the earth into a system of pipes under the streets. The natural hot water is also used to power large greenhouses, which supply fruits and vegetables that would otherwise be impossible to grow in Iceland. In San Bernardino, California, a geothermal system is used to serve 21 buildings. These buildings include the city hall, the county detention center, a hotel, etc. This geothermal district heating system is one of the largest in the world. Source 12 Source 6

success The majority of places that have implemented geothermal heating/cooling have resulted in success. With increased efficiency, reduced emissions, and a lower cost, geothermal heating systems seem to be very effective. Source 7

Challenges Geothermal power plants can only be created on geothermal hotspots, which includes less than 10% of the world. Drilling is a problem, as close access to hot water and rocks is needed. This is difficult since the resources are mostly underground. Source 8

Future research Future research should be done to find a way to implement geothermal energy in more locations. It should work to cut down on pollution created during the process of geothermal heating. Research should be done to lower the cost of drilling and find more efficient ways to explore for hotspots.

closing Geothermal heating/cooling is a very efficient and cost effective alternative to traditional systems. It has shown great success in the places it has been implemented. There are some challenges involved with geothermal systems. However, with future research, these problems should be solved. Questions?

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references 12. San Bernardino Geothermal District Heating System." Project Fact Sheet (n.d.): n. pag. Web. 16 Oct. 2016. 13. "Places Around the World That Use Geothermal Energy." Explore More. N.p., n.d. Web. 16 Oct. 2016. "Geothermal Heat Pumps Make Sense for Homeowners." (n.d.): n. pag. National Renewable Energy Laboratory. Web. 16 Oct. 2016. "Geothermal Research and Development Programs." Department of Energy. N.p., n.d. Web. 16 Oct. 2016. https://www.youtube.com/watch?v=mCRDf7QxjDk