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Geothermal Heating And Cooling – Harnessing the Earth’s Energy

admin — Mon, 09 Mar 2009 02:39:20 +0000

Imagine an HVAC and water heating system that can save 20% to 50% on a building’s energy costs while minimizing CO2 and carbon emissions. Imagine a system that is more reliable, is 2.5 to 4 times more efficient, provides the lowest life cycle cost, and a high degree of design flexibility.

Where can you find such a system? You need look no further than right under your feet. The earth is a huge energy storage device that absorbs 47% of the sun’s energy. When combined with the constant upward flow of heat from the earth’s red hot interior, the result is geothermal energy. Geo = earth, Thermal = heat. This clean, renewable energy is stored in masses of rock in the upper six miles of the earth’s crust. In nearly every state of the Union, there is sufficient geothermal energy to heat, cool and provide hot water for all types and sizes of buildings.

Temperatures near the earth’s surface remain relatively constant all year round – warmer than outside air in the winter, and cooler than outside air in the summer. Geoexchange systems (or ground coupled heat pumps) extract the earth’s heat during the winter and release it to the building interior. In the summer the process is reversed, drawing the hot air from inside the building and transferring to the earth. Nearly all geoexchange systems on the market can also provide low cost hot water – further increasing their operational efficiency

According to the EPA and DOE, geoexhange systems are the most energy efficient, environmentally clean and cost-effective space conditioning systems available. They rate the systems 40% more efficient than air source heat pumps 48% greater than gas furnaces and 75% greater than oil furnaces. Though geoexchange units do require a power source, they have a much greater energy efficiency ratio. In heating mode, the system will move at least three units of solar energy from the ground for each unit of electricity used.

There are three principal components in a geoexchange system: The ground loop, the heat pump unit and the heat distribution channel:

Ground Loop

For most buildings, the connection to the geothermal heat source is made via a ‘closed’ loop configuration. A series of flexible, high-density polyethylene pipes are installed beneath the ground in horizontal trenches or vertical holes. A fluid (water or a mixture of water and environmentally benign antifreeze) is circulated through the loops, absorbing the earth’s heat as it passes through the pipes and transporting it to the geoexchange unit inside the building. In cooling mode, the building’s interior hot air is absorbed by the unit, transported back through the loops and absorbed into the surrounding earth. Post-installation the holes or trenches are backfilled, then covered with native landscaping, grass or even parking lots.

Horizontal trenching is usually the most cost effective configuration when adequate space is available and trenches are easy to dig Vertical drilling is used when the land area is limited, or where the soil is too shallow for horizontal trenching. The loops should be installed by professionals who follow procedures established by the International Ground Source Heat Pump Association (IGSHPA), and are either certified by IGSHPA or can prove equivalent training by manufacturers or other recognized authorities.

Geoexchange Heat Pump

The most commonly used unit is the single package water-to-air heat pump, which combines heat exchanger, refrigerant piping, control valve, compressor, air coil, and fan, in one single enclosure about the size of a small gas furnace. The single package design is a major advantage over the “split” system used for air- source heat pumps. There are numerous manufacturers, brands and models of heat pumps available. They are rated by the Air Conditioning and Refrigerant Institute according to their respective Coefficient of Performance (heating) and Energy Efficiency Ratio (cooling). ENERGY STAR qualified geoexchange pumps consume 40-60 percent less energy than a standard heat pump.

Heat Distribution Channel

Conventional ductwork is generally used to distribute heated or cooled air from the geothermal heat pump throughout the building. A well-designed geoexchange system allows building occupants precise temperature control by room or by zone, with ideal humidity levels. The system requires no flue or chimney. There is no rooftop equipment or chilling towers that add weight to the structure or limit alternative roof styles such as vegetated roofing. Their compact size requires significantly less interior storage space. The heated water coursing through the system can be utilized for additional building uses, such as heating swimming pools and spas, melting sidewalk and parking lot ice and snow- even providing water for a car wash!

The largest commercial geoexchange system in the world is the Waterfront Office and Galt East Hotel complex in Louisville, Kentucky. This 1.7 million plus square foot complex is fitted with a 2,700 ton capacity geoexchange system, at a cost of $1,500 per ton. The project manager estimates that a conventional HVAC system with centrifugal chillers, cooling towers and insulated pipes would have cost from $2,000 to $3,000 per ton. Using Geoexchange technology freed up about 25,000 square feet of additional commercial space that would otherwise have been used for conventional equipment rooms. Energy savings are estimated at $25,000 per month while allowing individual temperature control to each room or suite. Annual maintenance costs are about 5 cents per square foot versus much higher average costs with standard HVAC systems.

Best of all, complaints about heating and cooling “have been virtually non-existent, whereas before we had frequent comments about lack of adequate comfort”

Daniele Loffreda is Managing Principal of Plateau Enviro Associates, a consulting firm specializing in green building, sustainable communities and marketing communications. He serves on the Board of Directors of the U.S. Greenbuilding Council Colorado Chapter, and is a Leadership in Energy and Environmental Design (LEED) Accredited Professional

Article Source: http://EzineArticles.com/?expert=Daniele_Loffreda

Geothermal Heat Pump Contractors, Installation, Specialists & Service – Offering ground source heat pump and geothermal heating system installation services, we are an established geothermal heat pump contractor of US.

How Is Geothermal Energy Turned Into Electricity

Guest — Sun, 23 Nov 2008 04:55:17 +0000

Making use of the natural heat from the earth, geothermal energy is a growing force as a source of renewable energy. It has already been used to provide power to 1.2 million homes in the United States. It has far greater potential and to both heat and provide electricity to homes and is yet to be properly utilized. That’s about to change.

Geothermal energy comes from a variety of sources of heat within the earth: decay of naturally occurring substances within the crust, the earth’s core and movement of continental plates as they slide against and underneath each other. Volcanoes, hot springs and steam vents represent the easily accessible points to this energy but most geothermal energy is trapped under the earths crust and must be accessed by drilling into the resource and harnessing the energy. The thermal energy in the uppermost 6 miles of the earths crust contains 50,000 times the energy of all the worlds gas and oil resources.

What Is Geothermal Energy?

Geothermal energy is the heat stored under the earths surface. In some parts of the world where the earths surface is thin or cracked, steam and molten rock can escape. These are usually locations of high seismic activity such as earthquakes and volcanoes. If water finds its way into these cracks, it becomes heated and may come to the surface as geysers, fumaroles, hot springs and mud pots.

Parts of New Zealand, Japan, USA and Europe have high geothermal activity. High grade geothermal energy such as geysers, hot dry rocks, mud pots and fumaroles is used to generate electricity. Geothermal energy can also be used as a heating source, for example in Iceland hot water is brought to the surface through a bore , then sent through insulated pipes into homes and radiator panels which provide heat. Over 80% of homes in Iceland are heated this way.

Although geothermal energy doesnt pollute the air with greenhouse gases, there are other environmental concerns about its use. Scientists are not sure how the long-term use of this resource could affect our underground water supplies. Some geothermal tourist attractions at Rotorua in New Zealand have already suffered a decline in surface activity due to the draw-off of geothermal fluid from the underground reservoir by domestic and commercial uses.

Geothermal energy can be broken down into 4 main types Geothermal energy can be broken down into 4 main types geopressured, magma, hydrothermal and hot dry rock.

Hydrothermal

This is the only type of geothermal energy that is currently producing commercial quantities of electricity and is derived from hot water and steam formed in porous or fractured rock at relatively moderate depths from 100 metres to 5 kilometres.

The hot water and steam come from the intrusion of molten magma into the earths crust or the deep circulation and heating of groundwater through faults and fractures.

To generate electricity, hot water at temperatures ranging from 180 250 degrees Celsius is brought from the underground reservoir to the surface through production wells and is flashed to steam in special vessels by release of pressure. The steam is separated from the liquid and fed into a turbine engine which turns a generator. Spent geothermal water is returned back to the reservoir to help maintain reservoir pressure.

Geopressured

Geopressured energy is derived from hot, pressurised waters containing dissolved methane, trapped at depths of three to six kilometres in sedimentary formations. The water temperature ranges from 90C to 200C.

Three forms of energy can be captured from geopressured sources chemical energy from burning the dissolved methane, hydraulic energy from the high pressure, and thermal energy from the hot water.

Hot Dry Rock

Under certain conditions granite at a depth of 3 to 5 kilometers under the ground can get to 250C. Unlike hydrothermal resources, the fractures and faults required to conduct water to the surface are not present, therefore water must be pumped into the rock at high pressure to create an artificial underground reservoir of steam or hot water.

A number of development projects continue into attempting to make use of hot dry rock to create electricity but factors such as cost and questions about resistance of the reservoir to flow, water loss and thermal drawdown remain. Costs are coming down though and geothermal technology in general will improve enough to make hot dry rock economically feasible.

Magma

Magma is the molten or partially molten rock that is found at depths between three and 10 kilometres beneath the Earths crust and reaches temperatures up to 1200C. While some magma resources are at accessible depths, a practical means of extracting energy directly from magma has yet to be developed, instead magma is used indirectly by exploiting the water it has heated. Magma is only accessible where volcanic activity or tectonic plate movement occurs.

The Future Prospect of Geothermal Energy in the US

An exciting new development in the future of geothermal energy in the United States has just been announced by the Department of the Interior who have promised to make 190 million acres of federal land available for geothermal power development. This is good news because the proposed land includes no environmentally sensitive areas such as national parks or designated wilderness areas.

By the year 2015 it is estimated that electricity from geothermal power production in the United States can reach 5,500 MW thanks to this new initiative. Its a positive move that will promote a form of renewable energy that has been used for years, but perhaps not to its full potential.

Source: Fumaroles

Google enhances green technology development

admin — Thu, 21 Aug 2008 01:56:30 +0000

Mega search engine Google.com, today announced an investment of $10.25 million in advancing the development of green technologies. Google is supporting a technology called, Enhanced Geothermal Systems, to help meet its goal of providing enough green energy to power a city the size of San Francisco. Through Google’s philanthropic entity Google.org, an initiative dubbed “Renewable Energy Cheaper than Coal” has been laid out to make this goal a reality.

Enhanced Geothermal Systems generates energy by pumping cool water 2-3 miles into a reservoir lying on top of dry, hot basement rock. The water is then pumped back to the surface at which point in condenses and creates powerful steam that is used to propel turbines. After the steam cools, it is re-injected back into the reservoir to begin the process again. This process allows energy extraction in areas that do not have natural steam pockets and hot flowing water.

The investments pledged by Google will go to help fund 2 companies and a university working on the development of Enhanced Geothermal Systems. $6.25 million will go to AltaRock Energy, Inc, which will work to reduce the cost and efficiency of EGS technology. Potter Drilling, Inc. has been given $4 million to design drilling tools capable of penetrating deeper and stronger rock. Southern Methodist University Geothermal Lab has been awarded a $489,521 grant to update geothermal maps and study geothermal resources in North America.

Google has recently been involved in many steps to reduce its environmental footprint and promote green technology. Data centers housing Google servers, are being designed to cut the energy needed for cooling to 50% of similar installations. The idea is not only to save money, but to create a self sufficient business model that promotes clean energy. This initiative is evident in the production of a 1.6 megawatt solar energy plant in Mountain View, California. Other projects include the Climate Savers Computing Initiative to create more efficient computers and servers, and the RechargeIT initiative aimed at developing electric vehicles and infrastructure.

Though $10.25 million may seem like a small amount to a power house company like Google, it shows considerable attention is being provided to changing the way we look at natural resources and energy generation. Google has the resources and intelligence to begin to leave a legacy that varies far from just creating one of the most popular websites of all time. Funding and support by Google leaders will help to attract more corporations with the potential for a green technology revolution. Though energy change falls on the hands of every citizen, major projects can not be completed without the funding and backing of large groups such as Google.

For Google Earth lovers, a map overlay has been provided by Google to show current distribution of geothermal resources. (Must have Google Earth)

Google has also provided an EGS policy brief to outline what the U.S. Government can do to help encourage the production and continued innovation of this technology.

Enhanced Geothermal Systems on YouTube

Geothermal energy holds key benefits to clean electricity

admin — Fri, 01 Aug 2008 22:36:38 +0000

Renewable energy projects are beginning to show the world just how efficient and safe, producing electricity can be. Rising costs of fossil fuels have given cities and nations a reason to look to nature to provide the power by which we live. While alternative energy is a fairly recent trend, countless hours have already been spent researching and experimenting to create sources of energy that can be reliable and efficient.

Geothermal energy, currently, only supplies about 1% of the world’s power, but the possibilities are virtually limitless. A 2007 study by MIT has published that geothermal energy could supply the world with enough energy to power our homes, businesses, and industries well into the future. Geothermal wells can be drilled all over the world and leave a relatively small footprint. Initial costs of constructing a new geothermal plant can run high, but with oil over $125 a barrel and rising, it would not take long to recoup those costs.

Geothermal energy generally works by drilling wells deep into the Earth and pumping water that travels down one well, is heated by hot rock, and is retrieved by the other well. The water traveling underground transforms into steam, which in turn, powers turbines connected to the power grid. Water that does not reach steam temperature, can be piped to low level heating systems such as those found in homes and greenhouses. Though efficiency may decrease as heat sources are depleted, the Earth’s mantle does replenish the heat stored in these deep rock layers.

The advantages of geothermal energy are many. This energy source is extremely reliable as it is available around the clock. Unlike solar energy and wind power, once a geothermal plant is installed, the exact amount of energy can be calculated which in turn will help to reduce future rate hikes. In combination with emission control systems, environmental pollutants can be cut to 0.1% of current fossil fuel plants. Also, this technology is scalable to allow energy production for large cities down to small towns.

Geothermal does have a few disadvantages which have kept it from becoming a front runner in energy production. The initial costs of drilling and constructing plants, can be very intimidating. As with all new technology, it takes a serious investment and well thought out plan to make this energy source function. In addition, concerns over contaminated ground water need to be further addressed. Additives used to increase the efficiency of steam rising to the surface, need to be properly controlled and kept separate from sources of drinking water.

Many different nations are beginning their journey to provide effective and reliable, geothermal energy. Germany has been developing this technology and has recently launched a massive plant that harnesses the heat of the earth. This plant can currently power about 10,000 homes or 3.4 megawatts of electricity.

The United States has been experimenting with geothermal power since the first generator was created in the early 1900′s. Today the U.S. generates about 2850 MW of electricity using geothermal technology and boasts the largest use of geothermal sources for power.

New sources of energy are being developed all over the world, and geothermal energy is just one more energy source in an arsenal that can help to eliminate our need for fossil fuels. By developing this technology further, we can begin to build a reliable source of energy that can help to backup the energy produced from wind, hydro, and other alternative energies.