An Application of CO<sub>2</sub> as a Refrigerant for Medium Temperature Heat Pumps
This paper presents the energetic and exergetic analysis of a transcritical carbon dioxide based heat pump cycle for heating. Recycled water (tw=25…40 °C) of food production enterprises is taken into account as a source of low potential heat. The theoretical and real CO<sub>2</sub> trans-critical cycles were analysed. Parameters, which characterize cycles from energy and exergy point of view were obtained. The exergy flow diagram (Grassmann diagram) shows that all the components except the internal heat exchanger contribute significantly to the irreversibilities of the system.