1 / 9

Understanding Geothermal Energy

Understanding Geothermal Energy. Dr. Michael Shepard Department of Geography and Geosciences. A GEOTHERMAL SYSTEM is a type of HEAT PUMP. Typical Heat Pump Operation. In winter , a heat pump extracts heat f rom the outside air. The colder it is o utside, the harder the system has to

layne
Download Presentation

Understanding Geothermal Energy

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. UnderstandingGeothermalEnergy Dr. Michael Shepard Department of Geography and Geosciences

  2. A GEOTHERMAL SYSTEM is a type of HEAT PUMP. Typical Heat Pump Operation In winter, a heat pump extracts heat from the outside air. Thecolder it is outside, the harder the system has to work. In summer, a heat pump dumps heat from the home. Thehotter it is outside, the harder the system has to work Image courtesy: http://www.srpnet.com/energy/pumpworks.aspx

  3. Just a few feet down, the Earth maintains a constant temperatureof ~50°F (10°C) year round. Geothermal heat pumps use the ground (geo) as a heat exchanger (thermal) INSTEAD of air like the more typical heat pump. • In the winter… • They extract heat from the Earth to heat your home. • It’s FAR more efficient to extract heat from a 50°F ground source than much colder outside air. • In the summer… • They dump heat from your home to cool it. • It’s FAR more efficient to dump heat to a 50°F ground sink than to much hotter outside air.

  4. Typical Setup -Wells are dug. -Plastic piping goes from unit into and out of the wells. -Piping is filled with antifreeze; often water mixed with alcohol. -Piping can also be horizontal, or placed in a pond, etc.

  5. In summer, heat from home is dumped into the Earth; Another way to think about it: cold water from the Earth is used to cool the home. In winter, heat from the Earth is used to heat the home; Another way to think about it: heat is extracted from the water coming from the Earth, and colder water is returned. Image courtesy: http://mvgeothermal.com/faq.php

  6. Advantages • Heat pump is inside and very quiet. • Most units also provide domestic hot water. • Not subject to wild swings in oil/gas prices. • Few moving parts and low maintenance. • System life 25+ years; 50+ years for the loop. • Very high energy efficiency (300%-600%, EPA). • Payback in 5-10 yrs over a conventional system. • One-time tax break of 30% of unit cost.

  7. Personal experience • System added in June 2008 • Replaced an older oil-burning forced-air furnace and exterior air-conditioner (HVAC). • Cost of the unit was similar to a new high-efficiency gas or oil furnace. • Extra cost of $7,500 was incurred to dig 3 wells (each 150 ft deep) and lay tubing in my suburban front-yard.

  8. Costs to date…. Summer Cooling • Sum of June-Sept 2007 Electric Bill: $595 • Sum of June-Sept 2008 Electric Bill: $585 Difference: - $10 Winter Heating • Sum of Nov 2007-Feb 2008 Electric Bill: $528 • Sum of Nov 2008-Feb 2009 Electric Bill: $740 Difference: $212

  9. Comparison of Costs • Cooling costs during the summer – negligible • Heating costs/month with oil: $275 • Heating costs/month with geothermal: $53 • Estimated payback time:3-10 yrs (depends on price of heating oil)

More Related