Exergy loss as a basis for the price of thermal energy

The actual value of thermal energy can only be obtained by a qualitative or exergy analysis of its conversion, transport and distribution. The exergy value of heat, or its capacity to perform work, can contribute to formation of a good basis for determining a fair economic price for thermal energy. This paper presents the basic principles required to describe the exergy states of a district heating system. The parameters that determine the thermodynamic states at important individual points in the system are analysed. The exergy loss in a district heating system which supplies consumers with heat at different temperatures results from the transport and distribution of thermal energy at a constant ambient temperature. This exergy loss was taken as a very important part of the model for the differentiated pricing of thermal energy. The proposed model can serve as a basis for differentiated tariff regulations, which, in addition to the amount of consumed heat, will also take into account the temperature of that heat. (C) 2002 Elsevier Science Ltd. All rights reserved.