In most cases large commercial & industrial CHP systems are driven by the electric generation capacity of the power generator ‒ electricity is the main output and heat is the by-product. In a Micro-CHP system typically used in homes or smaller commercial applications ‒ the system is typically heat-led ‒ heat is the main output and electricity is the by-product. Unlike typical CHP projects, Micro-CHP projects are sized not to exceed heating requirements.
The basic concept of an engine-driven Micro CHP is very simplistic. A liquid cooled internal combustion engine generates heat which is pumped through a heat exchanger and subsequently used for domestic use. A generator is driven by the engine and provides power for on-site electrical consumption. Approximately 92% of the energy produced as heat and electricity is utilized.
In a fuel cell based Micro CHP System, the equipment converts natural gas into power and heat without burning it. The fuel cell used Hydrogen extracted from Natural Gas and Oxygen from the air. The fuel processor removes odorants through an absorption bed, separates the hydrocarbon molecule through a steam reformer and then transforms the remaining CO into CO2 through a water gas shift ‒ converting to heat, power, and water as a byproduct. This electrochemical conversion device which produces electricity from fuel (hydrogen) and an oxidant
(oxygen) by chemically binding the two, releasing energy and creating water ‒ kind of like a battery that is constantly fed with fuel.
Four Micro CHP technologies are commercially available in NorthAmerica and four products are undertaking trials or working on North American Certifications.