Optimum design of a heat energy cooling system for obtaining customer satisfaction on economy and efficiency

摘要

The goal is to study the optimum design of a heat energy cooling which may have several series-connected counterflow heat exchangers on the vaporization and condensing sides of the cooling machine. The goal is achieved by finding design variables which maximise the satisfaction of the customer on the present value of operating costs of lifetime and investment of the cooling system and on the coefficient of performance, COP. The method of nonlinear optimisation with discrete, integer and continuous variables and random learning search algorithm is applied to optimise the thermodynamic system. Main variables available for the designer are the surface areas and temperatures of the vaporizer, the condenser and the other heat exchangers, heat capacity flow rates which are pumped between heat exchangers. Externally fixed parameters are the unit price of electricity, marginal costs of heat transfer surface areas, maintenance costs which are estimated by the ratio of annual cost and investment cost, annual peak power time, lifetime or utilization time and rate of interest. As results of the method, customised optima are found depending on how the customer defines goals, not only technical and economic but also biological comfort goals, and anticipates external parameters. This method allows the end user to study what-if optima taking into account global technological and economic trends which affect large cooling systems used in industrial installations, district cooling nets and large buildings.