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
Selfa Johnson Zwalnan; Nanchen Nimyel Caleb; Peter Muar Kamtu; Pahalson Cornelius Dawap
Abstract
This research proposes and evaluates an enhanced open-loop photovoltaic evacuated tube solar thermal collector hybrid energy system based on the developed multi-objective energy management strategy that manages and coordinates the hybrid system with a randomly unreliable grid power source to meet the ...
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This research proposes and evaluates an enhanced open-loop photovoltaic evacuated tube solar thermal collector hybrid energy system based on the developed multi-objective energy management strategy that manages and coordinates the hybrid system with a randomly unreliable grid power source to meet the health center's energy demand using TRNSYS software. A technical assessment of the system shows that the system is capable of meeting system load with a solar fraction of 67% even on days with an overcast sky level of radiation as low as 250 W/m2 and only 37.5% grid power availability. Overall, the system has a solar fraction of 80%. The implication of an 80% solar fraction is the large environmental benefit of reducing emissions and improved system economic viability, indicating that the formulated energy management achieves the goal of promoting renewable energy sources in the hybrid system. An economic analysis of the system revealed that it has a payback period of 6.9 years and Net Present Value of $36,985 at the end of the project's lifetime. This demonstrates that the upgrade of the traditional hybrid PVT with an evacuated tube collector operated based on the developed energy management strategy has met the goal of minimising emissions with significant environmental and economic savings.
Solar Thermal Engineering
Zaid Aljohani; Abdulkarim Asiri; Salem Al-Awlaqi; Turki Aljohani; Hossam AbdelMeguid
Abstract
NEOM is a proposed megacity and business zone in Kingdom of Saudi Arabia (KSA). It was announced in 2017 by Crown Prince Mohammed bin Salman with the goal of creating a hub for innovation and a hub for the future of living. NEOM is planned to cover an area of over 26,500 square miles and will include ...
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NEOM is a proposed megacity and business zone in Kingdom of Saudi Arabia (KSA). It was announced in 2017 by Crown Prince Mohammed bin Salman with the goal of creating a hub for innovation and a hub for the future of living. NEOM is planned to cover an area of over 26,500 square miles and will include a focus on sustainability and cutting-edge technology. The project is being backed by the Saudi Arabian government and private investment. The primary objective of KSA is to utilize the renewable energy resources in the NEOM region sustainably. This study evaluates the availability of solar energy in the NEOM region on a quantitative and qualitative basis, and a database of weather conditions such as temperatures and wind speed is collected and processed. NEOM has favorable climate conditions with an average annual radiation incident energy of 12.54 GJ/m2, wind speed of 15.68 km/h, and temperatures ranging from 16 to 38°C. Based on the analyzed data, the study investigates the potential of solar energy as a sustainable source and alternative to conventional fossil fuels. The utilization of solar energy could be applied in various ways including seawater humidification-dehumidification (HDH) desalination with productivity of 26-33 l/day/m2, solar cooling with an average load of 15 MJ/day/m2, green hydrogen production with rate of 41-47 mole/day/m2, and electrical power generation with rate 4.2-6.8 MJ/day/m2.
Solar Thermal Engineering
Mohammed Gwani; Abdullahi Bello Umar; Abubakar Gado Abubakar
Abstract
Traditional cooking methods using fuel woods can pose very serious challenges of local and regional air pollution and land degradation. These methods are inefficient, unsustainable and have serious implications to the environment. To overcome these challenges, a novel four reflectors solar baking oven ...
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Traditional cooking methods using fuel woods can pose very serious challenges of local and regional air pollution and land degradation. These methods are inefficient, unsustainable and have serious implications to the environment. To overcome these challenges, a novel four reflectors solar baking oven has been designed and tested for application in rural areas. The solar baking oven consists of four reflectors made from plane mirrors which reflect the Sun’s rays to the absorber plate placed at the baking chamber. The four reflectors intensify the incoming solar radiation into the baking chamber and increase the thermal properties and efficiency of the oven thereby resulting in shorter cooking time. The result obtained from the study showed that the oven can attain high temperature values. The temperature values are higher when the oven is loaded compared to when the oven is unloaded. When the oven is unloaded, the highest temperature attained by the four reflector solar baking oven is 128.6oC at 13:00 pm, as compared to 133oC at 13:00 pm, when the oven is loaded.
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.
Solar Thermal Engineering
A.R. Shateri; I. Pishkar; Sh. Mohammad Beigi
Abstract
Trombe walls and solar chimneys have been widely used by the construction industry for many years to heat buildings. In this study, the heat conductance of a Trombe wall was simulated and studied. The equations related to energy and momentum were solved numerically by use of the technique of control ...
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Trombe walls and solar chimneys have been widely used by the construction industry for many years to heat buildings. In this study, the heat conductance of a Trombe wall was simulated and studied. The equations related to energy and momentum were solved numerically by use of the technique of control volume. The equations were solved simultaneously using the Simple algorithm. At first, a base case was defined and simulated. A sensitivity analysis study was then performed to investigate the parameters affecting the performance of the wall. Based on the results, an optimized geometry was suggested which maximized the performance of the Trombe wall. In addition, the effect of the presence of the fins on the surface of the absorber wall was studied. In order to obtain the best geometry, the fins were assumed to have different shapes but a constant area. The results showed that the Trombe wall with rectangular fins demonstrated the best performance compared to the other fin geometries studied in this paper. The presence of rectangular fins can increase the room temperature by 1.24% compared to other fin geometries.
Solar Thermal Engineering
A. Naseri; M. Fazlikhani; M. Sadeghzadeh; A. Naeimi; M. Bidi; Seyyed H. Tabatabaei
Abstract
In this paper, a novel CO2 transcritical power cycle which is driven by solar energy integrated by a cryogenic LNG recovery unit is investigated. In the proposed cycle, the condenser unit of the CO2 power cycle is replaced by a Stirling engine. Thermodynamic and exergy analyses are carried out to evaluate ...
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In this paper, a novel CO2 transcritical power cycle which is driven by solar energy integrated by a cryogenic LNG recovery unit is investigated. In the proposed cycle, the condenser unit of the CO2 power cycle is replaced by a Stirling engine. Thermodynamic and exergy analyses are carried out to evaluate the performance of the presented system. Furthermore, in order to investigate the impact of utilization of Stirling engines instead of conventional condenser units, the proposed cycle is compared with the typical CO2 power cycle. The results show that employing the Stirling engine decrease the exergy destruction from 17% in the typical cycle to 8.85%. In addition, the total generated power of the novel system is considerably boosted up about 15 kW in off-peak times and more than 20 kW in the peak time. Moreover, integration of the Stirling engine also decreases LNG mass flow rate. Therefore, the required heat exchanger area in the LNG heater is also lowered.