CHP | Combined Heat and Power | Cogeneration

Combined 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:

On site production of power
Reduced energy costs
Reduction in emissions compared to conventional electrical generators and onsite boilers

CHP Applications

A variety of different fuels can be used to facilitate cogeneration. In gas engine applications CHP equipment is typically applied to:

Commercial
Redential
Industrial
Biogas

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 Efficiency

The 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).