CHP, Technology That Is Good For You And The Planet...CHP is an abbreviation for combined heat and power. This is the latest in heating technology. These systems produce electricity as well as provide heating for the home. Most nations' electrical systems are made up of power plants and the wires that connect them and our homes. This system of wires is referred to as the grid. This system has several disadvantages such as pollution of the air and inefficiency. As electricity flows through a wire, some of its' energy is converted to heat by friction losses. This energy is wasted and accounts for a substantial part of the energy produced. By producing the electricity where it is needed (distributed generation), through CHP systems, those distribution losses are eliminated. Also, the residential systems available in the U.S. use a natural gas powered engine. These engines run cleaner and therefore cause less air pollution than the power plants. Systems available in the U.S. and Japan utilize an advanced natural gas powered engine developed by Honda. The engine turns a electric generator to produce electricity and the heat produced during operation is used to heat the home. These engines are very quiet and efficient. One option in the United States is called FREEWATT (freewatt.com) and is produced by CLIMATE ENERGY LLC which is a partnership of ECR INTERNATIONAL and YANKEE SCIENTIFIC INC. Their warm air systems combine the natural gas powered engine with a natural gas fired high efficiency furnace. These systems consist of four basic parts. The engine is referred to as the powergen module. When the engine is operating, it produces 12000 btu/hr of heat and 1.2 kw of electricity. The electricity produced can supply power to the home and any excess that is produced goes into the nations' power grid. The homeowner is given credit by the utility company for the power produced through a program called net metering. The heat produced is transferred to a heat exchanger. This is similar to the radiator on a car and is called the cogen heat exchanger module. It is connected to a high efficiency gas furnace. (They offer single stage as well as two stage gas furnaces.) The furnace is referred to as the space heating module and works in the same way as other furnaces but it is not required to run the burners as much. During milder weather, the natural gas engine runs and water that is used to cool the engine is passed through a heat exchanger on the furnace. The blower on the furnace blows cooler air from the home over the heat exchanger where it picks up the heat. This heat is then distributed throughout the home through the conventional duct system. The cooler water is circulated back through the natural gas engine and the cycle is repeated over and over. As it gets colder outside, the CHP system runs more and more. Unlike a traditional furnace, this is a good thing because at the same time it is producing electricity. When the unit can not produce enough heat to keep up with the homes' losses, the gas furnace starts and supplements the heat from the engine. The final part of the system is the supervisory control system. This part conditions the electricity generated and allows system monitoring and control. Currently, the FREEWATT systems are only available in Massachusettes, New York, and Rhode Island. Another type of chp unit that is available in the U.S. is called ECOPOWER and is from MARATHON ENGINES (marathonengine.com). This unit has a higher electrical output at 2 to 4.7 kw and a larger thermal output at about 20000 to 42000 btu/hr. This system is designed for hydronic heating systems and has a large enough heat output to supply most of the heat required for a small home as well as the electricity required. The systems are currently only available for grid tie use and will not provide electricity when the grid is down during a power outage. A grid independent unit called ECOISLAND is due to be released in 2009. In Europe the homeowner has more options. One chp system called DACHS (www.senertec.de), operates on the same principle as decribed above. It has an electrical output of 5.5kw which is enough for a home and a heating output of about 10-12kw which will heat a smalller home. They also have a propane (lpg) version available. The VITOBLOC is a unit from Viessmann (viessmann.com) that can be fired by fuel oil,natural gas, or biogas. Other options that are available in Europe include the WHISPERGEN (www.whispergen.com), the stirling power module (www.stirlingpowermodule.com), and ECOGEN (baxigroup.com). These systems utilize a stirling engine. A stirling engine operates using the principle that a heated gas expands and a cooled gas contracts. This principle is used to move pistons to drive a generator. A fuel (natural gas, fuel oil, etc) is burned to heat the gas. The gas is cooled by water in the normal heating system. This can provide space heating as well as hot water for the home. The WHISPERGEN is powered by gas. The STIRLING POWER MODULE is designed to be used with the EASYFIRE 15KW wood pellet boiler from KWB (kwb.at). It is a four cylinder stirling engine that can produce 1 kw of electric power. The unit can also be retrofitted to existing EASYFIRE 15kw boilers. The ECOGEN model is powered by gas and is scheduled for commercial release in early 2009. It will have an electrical output of 1.1kw and a heating output of 24kw. Other CHP systems using fuel cell technology are in development. Fuel cells have several advantages such as they are silent because they have no moving parts. They also require minimal maintenance and produce negligible pollution. One such unit, the BETA 1.5 PLUS from BAXI-INNOTECH which is a part of the BAXI GROUP, is on field trials in the EU. It has an electrical output of 1.5kw and a heating output of 3kw. It is a proton exchange membrane fuel cell (PEMFC) which requires hydrogen for operation. Another system using solid oxide fuel cell (SOFC) technology is called AHEAD and is from ACUMENTRICS (acumentrics.com). It is a tubular SOFC system that can be fired by natural gas, LP gas, or hydrogen. A residential unit prototype was demonstrated in Germany. SOLAR CHP systems are now available from DAWN SOLAR (dawnsolar.com). These systems combine the traditional solar water heating system with photvoltaic (PV) panels and produce electricity as well as hot water for central heating and/or domestic hot water production.
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