Vapor Compression Cycle Simulation

Introduction

VapCyc is a general-purpose, steady state, vapor compression refrigeration system simulation tool. ISOC aspires to make VapCyc the most advanced vapor compression system modeling tool available. In this instance, most advanced, entitles a combination of simulation ability, coupled with functionality, currently not offered (at least in the public domain) in the field of vapor compression refrigeration simulation.

Goals and Implementation

The desired applicability of VapCyc is system simulation, for the purposes of:

• Analysis of the system, as a function of component performance
• Analysis of a component, as a part of a system
• Optimization of system level boundary conditions
• Optimization of component level parameters

To achieve these goals VapCyc is a simulation of a fixed configuration vapor compression system, consisting of:

• 1 Compressor
• 1 Condenser
• 1 Expansion Device
• 1 Evaporator
• (Future) Suction Line Heat Exchanger
• (Future) Accumulator

This system is general purpose in that each of the components can be selected and/or changed, and (if applicable) modified. VapCyc has a library of components, consisting of “fixed” models, as well as “generic” components (components which allow some or all of their properties to be modified). Fixed components mimic “real life” components, in that their performance is dictated by their geometry, which cannot be changed. An example of a fixed versus generic component is a compressor. A purchased compressor has a performance that is dictated by its boundary conditions and unchangeable geometry. A generic compressor allows the user to specify certain parameters. The Generic Compressor supplied with VapCyc has inputs for: Displacement Volume, RPM, Volumetric Efficiency and Isentropic efficiency.

It is desirable to offer a limited number of system level variables (those which would controllable with a “real” machine) that can be modified by the user. The system level variables available in VapCyc are:

• The refrigerant type
• System charge
• System boundary conditions
• Condenser coolant temperature (If applicable)
• Condenser coolant flow rate (If applicable)
• Evaporator heating fluid temperature (If applicable)
• Evaporator heating fluid flow rate (If applicable)