Guidelines of how to instrument, measure and evaluate refrigeration system in supermarkets

Abstract

Consulta en la Biblioteca ETSI Industriales (8859)

[EN] This Master Thesis aims at establishing guidelines of how to instrument refrigeration systems with the objective that will be possible and easy to evaluate its efficiency (Coefficient of Performance). Also we have put indicators of performance for systems that haven¿t got extensive instrumentation, how to calculate different system COP's and how to compare systems in field installations. It has been describe the different methods that can be used to calculate system performance. The project includes the main solutions of supermarket refrigeration systems such as conventional systems, CO2 trans-critical and cascade system. In previous project aimed at analyzing field measurements of supermarket refrigeration systems including 10 installations, it has been observed that the systems have extensive instrumentation; however, key parameters to perform proper performance analysis are missing. The main purposes of placing the instrumentation on the systems are usually for monitoring and control, but not to perform the system analysis. In some of this systems was necessary an extra instrumentation for the analysis. In other system was used some estimations due to the impossibility to install new measurements for reasons such as distant supermarkets or data acquisition software. In some projects were studied and compared different cooling systems that had many similarities in terms of refrigerant used and the thermodynamic cycle followed, although it was installed in areas in Sweden with different climatic conditions, and hence was interesting to show the variations in efficiency parameters. On the other hand has been also studied and compared systems completely different. In this case the key to the problem is to find relations and parameters which homogenize the systems owing to their differences. In this Thesis is not intended to analyze all the facilities again, nevertheless have been chosen the most representative to base the study. It is considered appropriate to develop general guidelines for the main solutions. For the analysis of a system, it is necessary to obtain a mathematic model that represents its behavior. The mathematical model is equivalent to a mathematical equation or set of them on the basis of which we know the behavior of a system. The mathematical model will be used to calculate the parameters needed for the system analysis; cooling capacity, COP low temperature and COP medium temperature form power consumption, temperature and pressure sensors.