Co-generation systems
Co-generation is the simultaneous production of two different energy forms from one single energy supply. The most common systems use natural gas to produce electricity and hot water or steam.
A co-generation unit essentially consists of a gas engine, where the shaft horsepower from the engine is used to drive an electricity generator, plus heat exchangers to utilise the by-product heat.
Co-generation is a very efficient way of utilising a primary energy source such as natural gas. Not only is there less reliance on electricity, but there is also emergency standby power generation.
Co-generation provides a cost effective alternative both to the use of boilers and other heating systems and to the purchase of electricity from the electricity supply industry. There are significant reductions in energy costs due to reduced electrical demand and usage charges. This is also one of the most effective and efficient means for heating and hot water for businesses.
Selection and design
The selection of a co-generation system of the correct size and type is crucial to the success of the system.
To select the optimum size co-generation unit, an energy demand profile for electricity and heat is required. This can either be measured or calculated, depending on whether it is for an existing or a new site. Small scale co-generation units typically have electrical outputs from 22kW to 900kW (electrical) from a single modular unit. Several units of different sizes can also be run in parallel to give a wide range of outputs and flexibility in operations.
Installation/location
Co-generation units are compact and modular and can normally be retro-fitted into an existing plant room. It is more economical to include a co-generation unit at the design stage for a new facility rather than installing a unit later as a retro-fit. In retro-fitting, boiler capacity can be reduced and installation costs for piping, electrical work and ventilation can be substantially increased.
Connections are required to a gas supply, an exhaust flue, hot water flow and return piping, and an electrical switchboard.