THERMO-HYDRAULIC OPTIMIZATION OF PLATE HEAT EXCHANGER IN ORC FOR A RATED HEAT LOAD

Abstract

The efficiency of an Organic Rankine Cycle which utilizes low-grade waste heat or heat from renewables like solar depends on the performance of its condenser infinite surface area, the infinitesimal temperature difference is needed for effective heat transfer. Practically, neither are possible in a heat exchanger and therefore designers tend to improve effectiveness at a finite temperature difference of the two fluid streams and finite areas that are practically possible, based on other design constraints like space. The present work aims to optimize geometrical parameters of a plate heat exchanger that meets fixed heat load so as to minimize the area of heat transfer and pressure drop. An evolutionary genetic algorithm is used with a single objective function combining the dual objectives area and pressure drop by giving appropriate weights to these functions. Optimization is carried out to find optimal geometrical parameters width, length, the distance between plates, and enlargement factor for minimizing the area and also the pressure drop. Also, different weights are given to the two objective functions to compare optimal design variables for varying requirements of objective functions and optimal values of geometrical parameters width, length, the distance between plates and enlargement factor are determined.