Utilization of Excess Production of Waste-Fired CHP Plants for District Cooling Supply, an Effective Solution for a Serious Challenge

Abstract

District heating-connected waste incineration plants face a serious operating challenge during the warmer months of the year when the heating load is quite low. The challenge is the difficulty of managing the extra municipal solid waste to be disposed of, exposing great pressure and cost on the plant. Conventionally, the solution is either burning the surplus waste and providing the extra cooling required for the condenser with a summer chiller and paying the tax of the total heat generation of the plant, or paying other industries to burn the waste for their specific applications. Both of these solutions are, however, costly. In this study, to address this challenge the utilization of the extra available resources of waste incineration plants for district cooling supply is proposed. Then, the proposed solution is analyzed from the thermodynamic and economic points of view. The feasibility of the proposal is investigated for a real waste incineration plant in Denmark and its 50 neighboring office/service buildings as the case study. The simulations are done based on real hourly data of the plant and economic parameters. The results show that for the case study for a plant with a thermal capacity of 73 MW, a district cooling with a peak load of over 20 MW could be perfectly supplied. The payback period of the proposed solution, including the cost of piping, absorption chiller, etc., can be as short as five years.