Cogeneration / Combined Heat & Power
Cogeneration or combined heat and power (CHP) systems are configured to produce both electricity and useful heat. GE Jenbacher CHP systems utilise heat produced during the combustion of the gas in the engine and can facilitate process efficiencies of more than 90%. Cogeneration is an efficient form of energy conversion achieving primary energy savings of roughly 40% by using a gas engine CHP as opposed to separate electricity and heat generation equipment. Cogeneration plants are typically embedded close to the end user and therefore help reduce transportation and distribution losses.
Benefits of Gas Engine CHP
The high efficiency of a CHP plant compared with conventional bought in electricity and site-produced heat provides a number of benefits including
- On site production of power
- Reduced energy costs
- Reduction in emissions compared to conventional electrical generators and onsite boilers
Heat sources
The heat from the generator is available in from 5 key areas:
- Engine jacket cooling water
- Engine lubrication oil cooling
- First stage air intake intercooler
- Engine exhaust gases
- Engine generator radiated heat, second stage intercooler
1, 2 and 3 are recoverable in the form of hot water, typically on a 70/90˚C flow return basis and can be interfaced with the site at a plate heat exchanger
The engine exhaust gases typically leave the engine at between 400 and 500˚C. This can be used directly for drying, in a boiler to generate steam, or via an exhaust gas heat exchanger combining with the heat from the cooling circuits.
5. The heat from the second stage intercooler is also available for recovery as a lower grade heat.
Alternatively new technologies are available for the conversion of heat to further electricity, such as the Organic Rankine Cycle Engine.
