Broken down into its functional blocks a CHP unit consists of four key items:
Prime Mover
Generator
Heat Recovery System
Electrical Control and Monitoringº
The prime mover is typically a gas reciprocating engine. These are almost always derived from commercially proven diesel engines. Modifications are made to provide the spark ignition for the fuel and to reduce the cylinder compression ratio. Very little else is changed which results in an engine that has very strong and reliable major components i.e. crank shaft, bearings etc because they have been designed to cope with the stresses of a diesel engine.
The typical generator used on ENER·G's range of cogeneration sets meets the requirements of BS EN 60034 and has been manufactured to ISO9001. It has windings specially designed to reduce certain harmonics which is essential for today's non linear loads i.e. computers, lighting. They can also be fitted with power factor correction equipment to ensure that the sets always generate at the optimum power factor for the site.
Depending upon the model type, the heat recovery system takes 'waste heat' from the engine jacket (just like a car's interior heater) and also from the exhaust gas (cooling it from 600ºC down to 120ºC in the process). For ease of maintenance and security of heat supply, the CHP unit is isolated from the sites heating system by a high efficiency plate heat exchanger. Most CHP units provide this heat to the site at around 90ºC however by using waste heat boilers or special high temperature engines, it is possible to generate MTHW or even steam from Cogeneration installations.
Electrical Control and Monitoring
ENER·G holds several national and multi-national patents relating to its sophisticated electrical control and monitoring systems. These systems are responsible for monitoring and controlling the energy flow to the host site and monitoring and controlling the prime mover. Whilst coping with the demands of these two major control tasks it also continuously monitors in excess of 70 parameters ensuring safe operation of the equipment. At head office the systems allow immediate diagnosis of faults and the aftercare teams are alerted to problems by the CHP unit itself, as and when they occur. Furthermore, the cogeneration aftercare team works through the same systems, giving a highly integrated monitoring and maintenance offering.