Calculation And Analysis Of Energy Consumption And Indoor Environment Parameters In Supermarkets

The heat leakage between cold display cases and the area outside them would likely cause their surrounding temperature to drop, resulting in indoor thermal comfort reduction, meanwhile heat recovery of display cases would likely affect their surrounding environment parameters and energy consumption in supermarkets, so it is necessary to construct a mathematical model for analyzing in detail how the surrounding temperature of display cases affects indoor temperature distribution in supermarkets and their heat recovery potentiality.A typical supermarket was chosen to measure its indoor temperature distribution in the summer and it is then found that there is a clear non-uniformity of temperature distribution in the supermarket environment which will lead to energy waste. In addition, based on the distinguishing feature of the temperature distribution inside the supermarket, it is divided into three subareas:the display cases area, the area close to display cases and the area far from display cases. Based on the heat recovery factor r and the temperature at the display case area (zoneⅠ), there are three operation modes:cooling, heat recovery and heating. By introducing the concept of zonal balance temperature, this paper established a dimensionless calculation model of energy consumption.Based on the on-site measurement, a simplified supermarket model is established in environmental chamber to simulate the energy consumption and environmental conditions in typical supermarkets. There are two refrigerated display cases, one HVAC system, several manikins, lighting and other electric devices in the chamber. Two cases process in the chamber and the measurement results indicates that the test results are familiar with them. In addition, a computational fluid dynamics (FLUENT) program with the RNG k-εmodel is applied to simulate the supermarket environment, and then the simulation results are validated against measurement data. The more or less good agreement between the simulation and measurement validates, So the environmental chamber can be used to simulate the supermarket environment and study the energy consumption and thermal environment in supermarket.For further study on analysis of three aspects affecting the energy consumption and thermal comfort in the store model, air circulation modes, air supply temperature and the supply airflow rates, this paper according to FLUENT simulation results about different cases and then obtains energy consumption and PPD value. By means of regression analysis in statistics, this paper gets several curve-fitting formulas:Energy= f1(modes, air supply flow rate, temperature), PPD=f2(modes, air supply flow rate, temperature). The curve-fitting formulas indicate that when supply air temperature was at around 20℃, the energy consumption attained the minimum; PPD decreases when supply temperature rises; PPD deceases almost linearly when air supply rate increases during our simulation range.To avoid the complexity of the FLUENT calculation and achieve a fast prediction about the indoor environmental parameters in supermarket, a supermarket environment zonal model was established which considering the energy consumption characteristics of supermarket equipments an environmental performance characteristics. At last, make display cases refrigeration systems, air curtain and zonal area coupled together, according to zonal model air flow calculation method, obtained air flow and temperature in each zonal area, meanwhile achieved a preliminary calculation and analysis.