Simulation of transient heat and mass flows in a supermarket

Abstract

This thesis concerns heat and mass flows in a supermarket. In the recent years progress in refrigeration and lighting technology has occurred leading to decrease in supermarkets’ energy demand. It was the reason to conduct this work, where hygrothermal flows within a modernly designed supermarket are analyzed and a transient computer model of these flows is introduced. A real supermarket located in Hanover, Germany, was a basis for model design. Its construction and equipment features were reflected in the model based on building plans, technical documentation and internet database collecting measurements from sensors. However, these information were limited, so some additional assumptions had to be made. Hourly values of outside temperature, humidity and solar radiation (last one obtained from program Meteonorm) for the whole year 2015 were input data for the created program. Results of the simulation included temperature and humidity of two zones, which the supermarket was divided into, with the resolution higher than one hour for better accuracy. They were subject of validation with real supermarket’s performance. Moreover, the program was capable of calculating values of particular heat and moisture flows. Testing under forced conditions is a way of model’s verification. The main problem with modelling supermarket’s inside air regarded high level of relative humidity during warm period and therefore three methods of decreasing it are presented: controllable fresh air supply, adjustable inside temperature and mechanical dehumidification. They allowed to reduce inside humidity to the level corresponding to real conditions in the supermarket. Better convergence is obtained for simulated temperature than humidity particularly in hourly perspective. Created model and obtained conclusions could help in the process of designing supermarkets or help to improve computer models of supermarkets.