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Go to Editorial ManagerIn several countries, residential buildings are responsible for high energy consumption. The majority of energy is consumed on air conditioning to ensure maximum indoor comfort. In Iraq, the demand for electricity increases significantly, especially during the summer for cooling purposes. In this paper, two technologies are proposed for buildings to reduce the cooling load. These approaches included the use of phase- changing materials (PCM) in different locations in the walls and roof, in addition to roof shading by galvanized iron. The effects of these proposals were simulated in the latest software tool (designbuilder) and compared with the standard building model. The results were clear when PCM was installed on the outer surface of the wall and roof, which achieved the highest reduction in the cooling load of about 18 %. While the roof shading method using corrugated galvanized iron proved its effectiveness by decreasing the cooling load to 5 % compared to the standard case.
Concerning commercial and residential buildings, one of the major parts related to water supply systems is the water storage tanks. For gravity- fed buildings, the tanks must be installed on the roof. In Iraqi summer, the temperature of water in storage tanks reaches above 50 °C due to high solar intensity, which makes it inappropriate for domestic usage. One of the proposed solutions to overcome this problem is feeding the hot water into an earth-water heat exchanger (EWHE) which consists of a set of buried pipes installed underground level to reduce its temperature. The storage tank and the earth-water heat exchanger were studied experimentally and theoretically by using ANSYS 20/FLUENT software to estimating the water temperature in the storage tank and the temperature of the water leaving the EWHE. The most important results obtained theoretically and experimentally that when using pipe length, pipe diameter, and mass flow rate of 100 m, 0.016 m, 0.7 LPM respectively, at a depth of 3 m, the water temperature decreases by about 15 °C. Also, the results have shown a good agreement between the experimental and theoretical works. One can conclude that an earth-water heat exchanger is an effective way to decrease the temperature of the storage water to an acceptable level for domestic usages.
In this paper, a theoretical study of the conventional solar-still system integrated via the design of heat recovery of air exhausted from the air conditioner condenser employing heat exchangers (WHRUs) was conducted. This study aims to improve desalination performance by compensating for the non-existence of sunlight during the night. A comparison was made between the desalination performance in the event of exposure to solar radiation and its performance in the case of exposure to the system (WHRUs). It was found that the (WHRUs) system has a minimal impact on the production of the conventional desalination rig during the night period, as the highest cumulative productivity in the presence of the (WHRU S ) reached (2.15 kg) in August. In contrast, the productivity dependent on solar radiation was (4.58 kg) for the same month, with the most significant percentage of improvement reaching (31.91 %).
A mathematic model is presented for solar updraft tower power plant with water-storage system. This model is developed to evaluate the effect of geometrical parameters of the solar tower power plant and thermal storage system as well as the wind velocity on the power production of the plant. The analysis based on variable solar incident radiation along the day. The results show that the tower tall, the tower diameter, the wind velocity, and the collector diameter have a significant effect on the power production while lhe thickness of the water-storage layer is shifted the peak value of the output power far away from mid-day and more smoothing tha output power curve. The results are compared with other model and experimental data. A good agreement is obtained.
The solar chimney is a natural draft device that uses solar radiation to provide upward momentum to the in-flowing air, thereby converting the thermal energy into kinetic energy through an air turbine which in turn can be converted into electrical energy. The main parts of the solar chimney power plant are a large circular solar collector, a tall chimney, and an air turbine. In this paper, a theoretical study was performed to evaluate the performance of a solar chimney power plant system in Basrah City, where sunny days and solar radiation are high. A mathematical model was developed to study the effect of various parameters on the output power of the solar chimney. I1 was found that the output power depends strongly on the chimney tall and the difference between the collector air temperature and the ambient air temperature as well as the outside heat transfer coefficient, which essentially depends on the wind speed.