CHP | Combined Heat and Power | CogenerationCombined heat and power (CHP), also known as cogeneration, involves the simultaneous production of electricity and heat. Cogeneration is a highly efficient energy conversion method. By utilizing gas engines, it can yield primary energy savings of around 40%, compared to separately purchasing electricity from the grid and gas for boiler use. When the fuel for gas engines is renewable, like biogas, hydrogen, syngas, or biomethane, CHP becomes an exceptionally sustainable electricity and heat source. Typically situated near end-users, combined heat and power plants help reduce losses during transportation and distribution. This enhances the overall efficiency of the electricity transmission and distribution network. In district energy setups, combined heat and power plants generate electricity and heat for clusters of residential or commercial buildings. For power users who prioritize supply security and have access to abundant gas, gas-based cogeneration systems serve as excellent captive power plants, located on-site. As a local power source, it enhances site resilience during grid outages through island mode operation features. Benefits of CHP for Your Business The high efficiency of a CHP plant compared with conventional bought in electricity and site-produced heat provides a number of benefits including:
CHP Applications A variety of different fuels can be used to facilitate cogeneration. In gas engine applications CHP equipment is typically applied to:
Heat Sources from a Gas Engine The generator's heat can be harnessed from five primary sources: 1. Engine jacket cooling water 2. Engine lubrication oil cooling 3. First stage air intake intercooler 4. Engine exhaust gases 5. Engine generator radiated heat, second stage intercooler Sources 1, 2, and 3 are recoverable as hot water, typically at 70/90˚C flow and return rates. These can be linked to the site through a plate heat exchanger. Engine exhaust gases, usually exiting at temperatures of 400 to 500˚C, can be directly utilized for drying, employed in a waste heat boiler to generate steam, or combined with cooling circuit heat via an exhaust gas heat exchanger. The heat stemming from the second stage intercooler is also viable for recovery, albeit as a lower-grade heat source. CHP System EfficiencyThe evaluation of gas engine combined heat and power (CHP) systems centers on the effectiveness of converting fuel gas into valuable outputs. The following diagram illustrates this principle. Initially, the energy within the fuel gas is transformed into mechanical energy through combustion within the engine's cylinders, resulting in the rotation of the crankshaft. This mechanical energy propels the alternator, generating electricity. While a minor inherent loss occurs in this process, in this instance, the engine's electrical efficiency stands at 40% (with INNIO's Jenbacher gas engines typically ranging from 40-50% electrical efficiency). |