Geothermal Heating and Cooling

Jeremy Arndt

09/08/09

POL 233

Geothermal Power

Heat stored in the earth can be extracted for heating and generating power.  This energy come from solar energy that the earth has absorbed and from mineral radioactive decay.  The area where geothermal heat has been available is limited to specific areas.  It is becoming more available as technology has advanced.  Geothermal energy can be used a large and small scale.  There are geothermal power plants.  It can also be used at individual house and businesses for heating. 

Geothermal energy has been utilized since back in the Paleolithic times.  It was used for heating public baths and under floor heating.  In the late 1800’s and early 1900’s they start working on more useful and efficient uses for geothermal.  As of 2004 there were over a million geothermal heat pumps in operation worldwide.  Technology has increased the availability and usage geothermal heat.  For example in Alaska they were able to generating power from a temperature as low as 57 degrees Celsius.

Geothermal power plants are one way that the US and other countries have made uses of geothermal energy.  There are 3 types of geothermal plants.  First off is the Dry Steam Power Plant.  This is where steam goes directly into a turbine which turns and generates electricity.  Another type is a Flash Steam Power Plant.  This is where water above 360 degrees is turned into steam to generate steam.  Finally there is the Binary-Cycle Power Plant.  This process is to utilize water temperatures that are below 400 degrees.  There are more than 20 power plants in the US .   There are a few draw backs to geothermal energy.  Geothermal plants do create some pollutants, although the amount is far less than fossil fuel plants.  These plants can have pretty high expenses, like drilling costs.

Geothermal energy is also being used by individual houses and businesses for heating.  This is only possible because of geothermal heat pumps.  This is similar to a regular heat pump except it uses heat from the earth.  In the winter it takes heat from the earth and pumps it into the house, and in the summer it takes heat from the house and pumps it into the earth.  This makes them much more efficient.  The main negative of this type of heating is the initial cost.  A typical system would cost around $7500, which is about double the price of a regular system.  That is just to by the system, there is also the cost of drilling which can range from $10,000 to $30,000.  The low utility costs would eventually pay for the extra initial expense.  Geothermal pump companies claim that the cost can be recovered between 5 and 10 years.
 

There are many companies out there making Geothermal HVAC systems now.  I just looked at one company as an example.  Eagle Mountain is one example which provides a variety of systems.  They have three main styles.(Denali, Sierra and Everest)  These systems have a range of sizes and costs depending on how much a consumer is willing to spend.  Another variation on systems is the type of loop.  There are basically 2 types, open loop and closed loop.   Closed loop is where both ends of the pipe connect into the pump.  There other type, which is open looped , is used for bodies of water or wells usually.  The water is circulated back to the earth after the heat has been used up.  The way the loop is installed can vary on the size of the land and whether there is a body of water close by.  If it is a small plot of land you would go with a vertical loop.  This is where the loop is placed in the ground vertically.  A home would need 3 to five holes that are 15 feet apart.  Another style is a horizontal loop, which is meant to be used for larger plots of land.  The loop is placed horizontally in the ground.  For this style you would need to of an acre of land.  The final type is that pond loop.  This type of loop is used if the home is near a body of water at least a half an acre and 8 foot deep.  Here the loop is sunk to the bottom of the pond. 

 I believe that geothermal energy is a very alternative to fossil fuel.  It is a very efficient way of heating and cooling you house and water.  The initial cost can be very high.  It will pay for itself in the long run.  On very important benefit I that there a very few pollutants involve.  One company that makes these systems claims that one of these units is equal to taking 2 cars off the road or planting an acre of trees each year.  All in all I believe the benefits far out weight the cons.