Dynamic Modeling of Vapor Compression Systems for Residential Heat Pump Applications with Alternative Low-GWP Refrigerants

Abstract

With the increased focus on reducing greenhouse gas emissions, low-GWP refrigerants, R32 and D2Y60, have been proposed as drop-in replacements for R410A in residential heat pumps. This thesis presents the development of a modeling framework in Simulink® for the dynamic simulations of such residential heat pumps. The framework is component-based, allowing arbitrary cycle configurations, and includes most of the relevant components. Finite-volume method has been applied to the heat exchanger. Compression and expansion processes are treated as quasi-steady state. The framework has been used to study the performance of the system using the baseline refrigerant and charge-optimized alternatives at ASHRAE test conditions, and the results have been compared against experimental data. Steady-state COP values fall within ±8% of experimental data. For the cyclic tests, the pressure and temperature behaviors compare well and accumulated capacity and power consumption errors are found to be within ±9%. Relative differences between the refrigerants are consistent between simulations and measurements. The framework shows potential for being used to simulate the operation of residential heat pumps under dynamic conditions.