Trigen or CCHP is an extension of the Combined heat and power plant. Combined Heat and Power (CHP) is the simultaneous generation of usable heat and power (usually electricity) in a single process. Through the use of an absorption cooling cycle, trigeneration or Combined Cooling Heat and Power (CCHP) schemes can also be developed.

The Trigen cycle utilises the waste heat from the electricity generation to not only provide hot water for space and water heating in winter but also chilled water for air conditioning in the summer by the inclusion in the system of an absorbtion chiller.

It seems strange to use hot water to produce chilled water but actually one of the oldest methods to mechanically cool a space is with absorption technology.

The refrigerant used is actually water, as that is the working medium that experiences a phase change that causes the cooling affect. The second fluid that drives the process is a salt, generally lithium bromide. The waste Heat from the CHP unit is used to separate the two fluids; when they are brought back together in a near vacuum environment, the water experiences a phase change to remix with the salt at a very low temperature (at normal atmosphere pressure, water vaporizes at 100 degrees Celsius; in an absorber, water vaporizes cold enough to produce 8 degress Celsius chilled water.)

Ameon has experience in the design and installation of Trigeneration plants and recently completed the plant serving a new 8000 SQ.M health care premises in Blackpool, Lancashire.