Solar Thermal Engineering
Mahdi Rezaei Rad; Rouzbeh Shafaghat; Amirhossein Aghajani afghan; Behrad Alizadeh Kharkeshi
Abstract
This experimental study introduces a solar humidifier-dehumidifier desalination model as a type of open-air-open water (OAOW) system; also, a new condenser with thermoelectric modules is applied in the dehumidifier unit. The experimental tests were done by considering climate conditions in the north ...
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This experimental study introduces a solar humidifier-dehumidifier desalination model as a type of open-air-open water (OAOW) system; also, a new condenser with thermoelectric modules is applied in the dehumidifier unit. The experimental tests were done by considering climate conditions in the north of Iran (Mazandaran province, Babol), and the effect of the inlet air's temperature and flow rate on the system's functional characteristics and condenser was investigated to improve the performance. Sensors measured the data related to the fluid temperature and humidity of the cycle at different points; other data was also gathered by psychrometric chart and EES software. The results section investigates water generation rate, GOR, coefficient of performance (COP), and condenser efficiency. The results showed that the highest water production is 420 g/hr, and the highest GOR is 0.19. Also, the water production rate and COP increase as the inlet air temperature rises. At temperatures lower than 75o Celsius, due to the air saturation, the maximum point of the water production and COP occurs at a flow rate of 0.022 kg/s. at high temperatures, increasing the flow rate raises water production, and on the other hand, the COP in the condenser is 0.8 at the highest point. According to the economic analysis done for the proposed model, the freshwater cost is 0.098-0.049 $/year for one liter.
Solar Thermal Engineering
Seyed Younes Afshoon; Rouzbeh Shafaghat; Mofid Gorji Bandpy
Abstract
This paper investigates the melting behavior of phase-change material (PCM) in an evacuated tube solar collector. The outer tube was made of borosilicate glass with a diameter of 60 mm, and the inner tube was made of copper with a diameter of 10 mm and length of 1500 mm. The heat transfer problem in ...
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This paper investigates the melting behavior of phase-change material (PCM) in an evacuated tube solar collector. The outer tube was made of borosilicate glass with a diameter of 60 mm, and the inner tube was made of copper with a diameter of 10 mm and length of 1500 mm. The heat transfer problem in heat pipe was investigated in four cases: finless, full fin, half fin, and third fin. The fins were cut from a 35 mm diameter copper tube and installed concentrically with the outer tube. The inner space between the absorber tube and the heat pipe was filled with stearic acid as the PCM. The numerical simulation was conducted using the Ansys Fluent 2022 for the laminar incompressible Newtonian fluid flow in the transient state via the enthalpy-porosity model. The initial temperature of PCM was 27°C, and liquid fraction was zero at the beginning of the simulation. After validating the numerical results with experimental ones, the collector performance was evaluated by considering the four temperatures of 68, 72, 76, and 80°C for the fin and heat pipe at three different times t = 22, 55, and 110 s. The results showed that by increasing the fin area in three cases of third fin, half fin, and full fin, the melting and storage time of PCM were reduced by 6%, 44%, and 87%, respectively. Also, as the Estefan number increased from 0.007 to 0.05, 0.09, and 0.13, the process of PCM melting decreased by 75%, 85%, and 92%, respectively.