What are geothermal heat pumps?
Wednesday, June 1, 2011 at 04:32PM What are geothermal heat pumps?
(An example of a GHP - http://www.altdotenergy.com/2009/04/residential-geothermal-energy-incentives-cap-lifted/)
Geothermal heat pumps (GHP) are the most energy-efficient, environmentally clean and most cost effective systems available for heating or cooling a building or home. Below the frost line of the Earth's crust (about 10 feet down), the Earth provides a nearly constant temperature of 54 degrees Fahrenheit. A GHP taps into this energy to provide heating in the winter and cooling in the summer.
Also called a geothermal heating system, a GHP is composed of three main parts: a ground loop system, the heat pump, and a distribution system.
The ground loop system, also known as the ground heat exchanger, is buried below the Earth's surface. These pipes or "coils" are filled with water or a water/antifreeze solution. During the winter, when the surface air is much cooler than the temperature below ground, the solution circulates in the coils underground and absorbs the Earth's heat. This heat is carried to the surface and transfers to the heat pump. The heat pump then warms the air within the premises using the distribution system. Generally, your regular heating system will further warm the air as needed to reach comfortable temperature levels.
A geothermal heating system works in reverse during the summer time. When it is hot outside, the temperature below the surface is cooler than the summer heat. So, the solution in the loop absorbs heat within the premises and sends it underground. The ground's lower temperature cools the fluid, then it is circulated back through the GHP.
There are four major types of closed loop geothermal systems: horizontal loops, vertical loops, slinky coils and pond loops. Typically, a home will use a vertical loop system (going straight down) because they do not have the space needed to spread out a ground loop system horizontally.
A geothermal heating system's thermal efficiency far exceeds that of other electricity based systems. This is why the major advantage of a GHP is cost savings! A geothermal heat pump can reduce a home's annual heating energy use by 50 to 70 percent.
Another notable advantage is that geothermal heating systems are environmentally friendly. Because a GHP draws on soil temperatures to heat or cool your home, it reduces your home's energy use and greenhouse gas emissions.
With millions already in use worldwide, geothermal heat pumps are certainly an Earth friendly technology for the future of our planet.