Supply water temperature regulation problems in district heating network with both direct and indirect connection

General form of equations for hot water temperature in house installation and district heating system according to the outside temperature are well known. The influence of heat exchanger type and its fouling on heat output in DH system is experimentally determined. When both direct and indirect connections are applied to the same district heating network, certain exploitation problems have been noticed due to real behavior of heat exchangers. Two technical possibilities are discussed in order to overcome problems.