ABSTRACT
District heating systems suffer from the low heating demand in the summer accompanied by the low flow rate of water through the pipeline. This will cause the temperature and velocity of water at the district heating to decrease especially when the supply location is far from the end-user location. Therefore, for addressing these challenges, the power plant oversupplies hot water in the pipeline at the origin. In this way, water can reach the end-users at the desired temperature, which create another problem and that is too much hot water at the destination. Therefore, the district heating needs to recirculate this into the return line which means wasting a lot of energy and requires larger cooling equipment. In the proposed solution, a solar chiller is further boosted by the excess heat from the district heating side. The proposed hybrid system is composed of a waste incineration plant, solar thermal field, absorption cooling machine, and district heating/cooling unit. Initially, the district heating network is investigated from an economic point of view then the proposed hybrid system is investigated from the 4E (energy, exergy, environment, and economic) aspect. The size of the cooling system, the solar thermal power plant, the temperature of the flue gas, and the volume of the hot storage are found to be 10.2 MW, 14.2 MW, 1,100 K, and 500 m3, respectively.
