Systems with Low Energy Consumption
Ali Fahim; Ahmad Nazari; mohammad Zamen; Amirreza Salamat Asrami
Abstract
A significant portion of energy consumption, particularly during the summer, is attributed to cooling demands in buildings. The most common methods for providing cooling are vapor compression and absorption refrigeration systems. However, in recent years, alternative methods based on adsorption have ...
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A significant portion of energy consumption, particularly during the summer, is attributed to cooling demands in buildings. The most common methods for providing cooling are vapor compression and absorption refrigeration systems. However, in recent years, alternative methods based on adsorption have been explored, and some systems have even reached the commercial market. In Iran, however, such systems have only been investigated at the laboratory level. The goal of this study experimental evaluation of a silica gel–water adsorption cooling system. The constructed system included an adsorbent bed filled with silica gel, a condenser, an evaporator, a heating unit, and a cooling water circulation system. A key feature of this design is the use of a chamber for both the adsorbent bed and the condenser which makes the system simpler. After construction, the system was tested and its performance data were collected. The cooling energy produced at the end of each cycle was measured based on the temperature change in the evaporator. According to the results, the cooling energy per cycle ranged between 1.3 and 1.8 kWh, with a maximum heating energy requirement of approximately 1.8 kWh. Based on various experimental runs, the coefficient of performance (COP) of the system was calculated to be in the range of 0.035 to 0.048. The use of an integrated chamber simplifies the system, but it results in reduced performance.
Photovoltaic Systems
H. Eshghi; M. Kahani; M. Zamen
Abstract
The cooling process of photovoltaic (PV) panel is one the main issue in in the field of solar systems. The temperature of solar cells increases when solar radiation and also ambient temperature increase. Increasing the cell temperature reduces the electrical output power of the panels as well as their ...
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The cooling process of photovoltaic (PV) panel is one the main issue in in the field of solar systems. The temperature of solar cells increases when solar radiation and also ambient temperature increase. Increasing the cell temperature reduces the electrical output power of the panels as well as their lifetime. To solve this problem, various methods have been provided for cooling the panels. One of these methods is the application of heat pipes. In this research, a PV panel equipped with thermosyphon heat pipe is introduced. The thermosyphon was connected to the back sheet of the panel to enhance the cooling effect of the PV system. Instead of using polyvinyl fluoride polymer, unlike conventional panels, an aluminum plate was used to connect the heat pipe to the back of the panel to have better cooling. In addition, to increase the heat transfer area between heat pipe and back surface of the panel, a special groove was drilled on the aluminum plate. Three different filling ratios (25, 45 and 65%) of distilled water as the working fluid were used in thermosyphon. The best performance of the systems was obtained at 45% of filling ratio, in which, the electrical power of the PV panel equipped with heat pipe was around 3.2% better than the conventional PV panel. In this case, 6.8 °C temperature difference was observed in the water tank connected to the condenser section of heat pipe which means that 54 kJ heat was transferred to the water in the tank.