Experimental Based Method for Sizing Photovoltaic Power System Suitable for Cooling Greenhouses.(Dept.E)

Abstract

This paper presents new method for designing photovoltaic power system (PVPS) suitable for cooling the greenhouses. The designed PVPS is installed at Serw station at cooling cucumber crop. The greenhouse, under test has the geometrical configuration of, 6m length, 4m width and 2m height. The indoor temperature of the greenhouse is 50oc before cooling. This level of temperature has a harmful effect upon the cucumber. Hence, the cooling system must be installed for increasing the mass production of the crop within the greenhouse. PVPS is designed to operate the cooling system contains one blower and a fan, they require electrical energy of 1.7KWhr. This paper illustrates new method for designing the PVPS. The proposed method is based upon the experimental behavior of one module of solar cells array and lead acid battery. The method strategy depends upon the energy balance principle. An algorithm and flow chart illustrate the design steps are built up. Graphical charts and mathematical model are obtained to determine the array and battery size required for supplying the previous load (1.7 kWhr). Consequently, the charts obtained can be used for designing any small PVPS system provides desired load. The results obtained by the proposed method are compared with that obtained by the famous method (NASA method). The paper presents that the two methods are approximately identical. The tested greenhouse requires PVPS of 2 modules 75 W peak each and two batteries of 80 Ahr lead acid battery.