Analysis of energy recovery from surplus water pressure of municipal heat distribution network

Abstract

The correct operation of a heating network system depends on appropriate water parameters of a network, especially a water pressure. The heating source provides the water pressure depending on the worst conditioned water main in the network. The structure of the water heating network depends largely on the landform features and, in many situations, a pressure zone with the pressure reducing valves is required. This excess pressure gives an opportunity for energy recovery during reduction of the pressure from the system. This can be done by substituting the existing mechanical pressure reducing valve by a water turbine combined with an electrical generator. In the paper, an example of a heating system is analysed and possible recovered energy is calculated assuming a specific value of energy conversion system efficiency. The real tests of the prototype reducer showed possibilities to achieve satisfying efficiency of an energy conversion. The presented economic analysis confirmedpotential of the proposed system.