Μελέτη της απόδοσης του ηλιακού συστήματος κλιματισμού στα εργαστήρια μηχανολογίας

Abstract

The main objective of this project is to describe and analyze the solar cooling and heating system installed at the Mechanical Engineering laboratories of the Cyprus University of Technology (CUT). The system consists of three absorption chillers each having a cooling capacity of 95kW, four hot water storage tanks having a total capacity of 16100 liters, two oil fired boilers of 155kW capacity each, a closed type water cooling tower with a capacity of 425kW and 69 evacuated tube solar collectors having a total absorber area of 310.5 m2. The scope of the project was to study the behavior and performance of the system over a period of one year both of the cooling and heating modes and to carry out an economic assessment of the system and of the payback period required. Because of various problems encountered related to the system, the scope was modified to study in detail the performance of the absorption chillers during the summer months, and suggestions are made to further reduce the power consumption and to increase the system efficiency. The Building Management System (BMS) installed was used to record all the system parameters through the whole year of study, which were then analyzed and recorded in charts using EXCEL. Due to the limited use of the building during the summer months and the relatively low requirement for cooling load the mean value of the coefficient of performance (COP) of the chiller (since only one chiller was operational through any one day) is 0.68 even though the water entering the chiller was at a relatively low average temperature of 69 °C. The study has shown some problematic aspects of the system which needlessly consume excessive energy and suggestions are made for rectifications. Furthermore, suggestions are given to improve the efficiency of the system. The main cause of excessive energy consumption is related to the general pump over-sizing and the management of the excessive un-used solar energy. For both of these problems an economic analysis is carried out to make the system both economically viable and efficient. The results of this study are very important because through suggestions it is possible to increase efficiency, reduce energy consumption and make the system economically attractive to users thus increasing the use of solar energy and in general increase green energy production.