Thermodynamic Analysis of a Cascade Refrigeration System

Abstract

There is a need for cooling by using the waste heat energy in food industry. Absorption cycles can be driven by waste thermal, geothermal, solar or industrial processes energies. In this study, cascade refrigeration system is thermodynamically modeled, and analyzed by using first law of thermodynamics, and exergy method. Thermodynamic properties such as pressure, temperature, entropy, enthalpy, exergy, mass flow rate in each stream are calculated for 50, 75, 100• C and for 0.8, 1.0, and 1.5 MPa pump pressure. A computer program is used that was prepared in FORTRAN by the author for the analyses. It is found that the compression-absorption cascade cooling cycle is appropriate for most of the kind of waste heat applications. Increase of the generator inlet heat temperature increases the generator inlet heat, the absorber outlet heat and the condenser 2 outlet heat energies and decreases the coefficient of performance of the absorption and the overall cycles. The generator heat decreases with increase of the pump pressure. Also increase of the pump pressure decreases the coefficient of performance of the absorption and the overall cycles. Increase of the pump pressure and the generator temperature decreases the exergetic coefficient of performance. Increase of the generator temperature and pump pressure increases the generator inlet exergy. It is concluded that increase of the generator temperature and the pump pressure increases the total destructed exergy of the cycle.

Exergy Analyses of Vehicles Air Conditioning Systems for Different Refrigerants

“…In industry, cooling, refrigeration and cryogenic applications are used widely. Many studies are carried out about the performance and exergy analyses of these applications [1,2,3]. There is an air conditioning system operating according to the vapor compression refrigeration cycle in the vehicles.…”

Thermodynamic Performance Assessment of Different Fluids in a Typical Organic Rankine Cycle for Usage in Municipal Solid Waste Power Plant

“…Some researchers focused on the selection of proper and more effective working fluids [9][10][11][12]. There are also many studies on thermodynamic analyses of similar energy conversion systems [13][14][15][16][17].…”

Design of a Laboratory Unit Air-Conditioning System with Matlab/Simulink Software

“…The typical HVAC systems have one refrigerating system for cooling and dehumidifying, heat pump for heating, humidifying system, and fan for ventilation [7][8][9]. Such complex structure and the developments in this area require training of the technical staff.…”

“…The aim of current study is to simulate this unit correctly in Matlab/Simulink [10,11]. Necessary models are simulated and the results are compared with the theory [5,8,12,13].…”