Introduction
Combined Heat and Power system is a technology that produces electricity and thermal energy in the same process. In this way, optimum use can be made of the energy available from the fuel. During the electrical power generation, heat is lost, which is used to increase the internal energy of the fluid, water in this case, through the exchangers. Hot water is either directly pumped to the end user during the winter season of the year or it is used to power refrigeration cycles through the Absorption Chiller during the summer. The production of chilled water turns the system into a tri-generation process and is called CHPC , which stands for combined heat, power and chilling system. Control and temperature sensors connected to a central control system are also used in order to switch the above processes and to provide a fine tuning of the controls to ensure operation at optimum efficiency.
The system that is used by Loughborough University contains two boilers and two chillers, which are set to work in certain conditions. The conditions are if the CHP heat and power rejection is insufficient to drive the system and the demand of heat and power are at its maximum point.
The Loughborough University CHP is a Perkins spark ignited Gas Engine of 30.56 litre capacity situated next to the village bar in campus. The CHP provides 1.6 MW of electricity and 1.63 MW of Heat. The system also contains an Absorption Chiller which makes the process a tri-generation process. The refrigerant that is used in the system is water, lithium bromide is the absorbent, which are used in the water-lithium bromide vapour absorption refrigeration system. A solution of water and lithium bromide is pumped to the generator and is heated where the water refrigerant gets into a vapour state and moves to the condenser where it’s heated. At the same time lithium bromide goes back to the absorber where it absorbs water from the evaporator. This