Engineering Energy: Geothermal

Geothermal Energy, a more relevant resource

istock_000014705708xsmallEnergy today comes from many different sources. One of the sources becoming more and more relevant is geothermal energy. When groundwater seeps back into the earth and comes in contact with rock that is heated by the earth’s core, a geothermal reservoir is created. By drilling into the area, the energy created by the hot water and steam can be released.

Wells, somewhat similar to the ones used for oil and natural gas extraction, allow the groundwater deep in the earth to be tapped for the process. More common energy plants are considered flash power plants and utilize the water from the ground.  Groundwater under pressure is brought up from the reservoirs and into a flash tank where a portion of the water turns to steam. The steam is directed through a turbine which spins a generator creating electricity. The water that does not become steam is pumped along with any condensed water vapor, back into the reservoir.

A lesser used plant design is the dry steam power plant. This design utilizes the steam trapped in the rock and uses little or no water. As in the design of a flash power plant, the steam is piped up from the ground and through a turbine, causing the turbine to spin a connected generator, creating the electricity. The condensed water vapor is the returned to the geothermal reservoir where it will begin the cycle again. The advantages to using geothermal energy, is that there are practically no greenhouse gasses emitted into the air making it one of the cleanest renewable energy sources available.

Smaller systems for commercial and residential applications are primarily used for heating and cooling. In these applications, the use of geothermal or ground source heat pumps will be used as an exchange medium between the constant temperature of the earth and the outside air temperature. In the cooler months the heat can be extracted from the ground and transferred to the building for heating. In the warmer months the process can be reversed and heat extracted from the building and returned to the ground source. Geothermal heating works well in open area building by utilizing a floor heating system rather than a radiator or forced air type due to the relative low temepture needed.

Geothermal Engineers, working in tandem with geologists and mechanical engineers have been and are currently working on newer and more innovative ways to utilize geothermal heat sources. Other than the initial price of the investment involved in setting up plants and drilling for geothermal energy, the actual production costs are quite low. As we develop better ideas on how we extract, store and utilize geothermal energies, as well as being labled “green enregy”, we can conclude that we will expect to see a significant rise in research and production.

By | 2017-06-08T15:43:01+00:00 July 23rd, 2012|Mechanical Engineering|0 Comments

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