Cogeneration and trigeneration

Cogeneration means production of heat and electricity simultaneously in one device. Most of combustion engines (piston, turbine) used for electricity production have a problem with the utilization of waste heat. Only a third of the energy contained in fuel is transformed into mechanical energy – rotating movement of spindle driving the electric generator. The rest comes in form of residual heat. A cogeneration unit is designed to achieve desired heating power, the production of electricity is a bonus. Stable piston engines are the simpliest cogeneration units. The most common case is the transformation of a car engine. Car factories produce engines with a wide power possibility – from tens of kiloWatts to one megaWatt of electric power. The heat is utilized for heating and the electricity can be sold into distribution network.

It is not very complicated just a rational attitude to energy utilization. Problems with most technologies producing heat happen in the summer. When there is 30°C outside, the possibilities of using heat produced in a cogeneration unit are not many, except specific cases (drying plants for wood or food). Here we can consider the use of trigeneration – production of cold from heat in absorption circulations. According to the Opens external link in new webpage the basic principle of absorption cirlulations is heat transfer in which the refrigerant is by low pressure absorbed by a suitable substance (the absorbent). It is then transported into an exchanger which operates by higher pressure, there the refrigerant is again with supply of heat released from the solution by boiling. It results into a refrigerant with higher pressure which corresponds with the conditions of condensation. The cold  obtained in this manner can be used to cool buildings.