18 May 2017

O.3.2.3 Steady State Modeling of Advanced Vapor Compression Systems with Multiple Air and Refrigerant Loops

The use of heating, ventilation, air conditioning, and refrigeration (HVACR) systems is always increasing. Thus, there is continued research focused on improving the efficiency and reducing the negative environmental impact of these systems. The basic vapor compression cycle has already reached its limits. Hence, researchers are investigating more creative and complex cycles to improve the capacity and efficiency. Furthermore, there is increased effort towards finding lower GWP alternative refrigerants, some of which require novel system design to improve efficiency or maintain capacity. This motivates the development of a fast and robust simulation tool for steady analysis of complex vapor compression systems. This paper presents a comprehensive vapor compression system steady state solver which has several novel features compared to the existing solvers. Firstly, this solver is capable of simulating large number of different designs of vapor compression systems. This includes arbitrary system configurations, multiple air and refrigerant paths, and user defined refrigerants. The solver uses a component-based solution scheme in which the component models are treated as black box objects. This allows different vapor compression systems design engineers, and manufacturers to use the solver without the need to expose any possible confidential component data. The solver is validated using a residential heat pump system, a vapor injection flash tank system, and a CO2 two-stage refrigeration system and the preliminary modeling results match the experimental results within 5%, 10%, and 3% accuracy, respectively.