Modelado de un sistema de refrigeración caracterizado en un rango amplio de condiciones de operación

Abstract

In this study a methodology to develop a semi-empirical modelling of a classic refrigeration system is presented, which is composed by a compressor, a condenser, an expansion valve and an evaporator, and is characterized under extended operating conditions. The models are developed in a modular way, thus these can be adapted to a similar configuration related with refrigeration, air conditioning and heat pumps. The results of the modelling are compared with experimental results obtained in a refrigeration system composed by a scroll compressor, a plate heat exchanger as evaporator a louvered fin and flat tube condenser. This comparison is also used to determine some empirical parameters of the models. First the models are validated individually and then these are interconnected to develop the global model. In this approximation, the condenser imposes the condensing pressure, the evaporator the evaporating pressure and the compressor the refrigerant flow rate, among other intermediate variables. The main outputs of the model are the evaporator cooling power, the compressor power and the system COP (Coefficient of Performance). The model is validated with 76 tests developed in a steady-state, by obtaining a COP with a difference lower than 8% between the measurements and the results of the model, which is here considered as acceptable. Finally, by simulation, the model is used to determine the refrigeration system working domain.