scholarly journals An Investigation on the Effect of the Total Efficiency of Water and Air Used Together as a Working Fluid in the Photovoltaic Thermal Systems

Processes ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 516 ◽  
Author(s):  
Mustafa Atmaca ◽  
İmdat Zafer Pektemir

The temperature of a PV (photovoltaic) panel increases when it produces electricity but its electrical efficiency decreases when the temperature increases. In addition, the electrical efficiency of the PV panel is very limited. To increase the PV efficiency, the rest of the solar irradiance must be used, together with the temperature being kept at an optimum value. With this purpose, an experimental study was conducted. Firstly, two specific photovoltaic-thermal (PV/T) systems were designed. The first was the PV/T system which used only a water heat exchanger. The other one was the PV/T system that used a water and air heat exchanger. In the latter PV/T system, air passed through both the top of the PV panel and the bottom of it while water passed through only the bottom of the panel in a separate heat exchanger. In this way, the water and air absorbed the thermal energy of the panel by means of separate heat exchangers, simultaneously. In addition to the two systems mentioned above, an uncooled photovoltaic module was also designed in order to compare the systems. As a result, three different modules were designed. This study was conducted in a natural ambient environment and on days which had different climatic conditions. The thermal, electrical and overall efficiencies of each PV/T module were determined. The results were compared with the uncooled module electrical efficiency. The results showed that when water and air were used together, it was more efficient than single usage in a PV/T system. The thermal gain of the working fluids was also found to be fairly high and so, the gained energy could be used for different purposes. For example, hot air could be used in drying systems and air condition systems. Hot water could be used in hot water supply systems.

2011 ◽  
Vol 374-377 ◽  
pp. 242-247 ◽  
Author(s):  
Ning Jun Li ◽  
Zhen Hua Quan ◽  
Yao Hua Zhao ◽  
Na Na Guo

A new photovoltaic/thermal (PV/T) system based on the micro plate heat pipe is established in this paper, and the experimental study is conducted for nature convection, forced circulation cooling and common PV module. the experiment carried out on May showed that the highest temperature were 50°C and 52°C respectively for nature convection and forced circulation cooling module, the daily average electrical efficiency were relatively increased by 13.1% and 6.1% than common PV modules, the total efficiency ηo reached 54.2% and 50.3%, and the primary-energy saving rate were 73.1% and 68%.the result indicates that in the new PV/T system the temperature of the PV modules is reduced, the electrical efficiency is keeping at a high level, and the waste heat can be made good use to get hot water, therefore the solar energy utilization efficiency was raised greatly.


2022 ◽  
Vol 961 (1) ◽  
pp. 012065
Author(s):  
“Miqdam T Chaichan ◽  
Muhaned A H Zaidi ◽  
Hussein A. Kazem ◽  
K. Sopian

Abstract Today, photovoltaic modules have become accepted by the public and scientists in the production of clean electricity and as a possible alternative to electricity produced from fossil fuels. These modules suffer from a deterioration in their electrical efficiency as a result of their high temperature. Several researchers have proposed the use of high-efficiency hybrid photovoltaic (PV/T) systems that can cool PV modules and also produce hot water. Improving the PV modules’ electrical efficiency increases the investment attraction and commercialization of this technology. The possibility of restoring the electrical efficiency of the photovoltaic panel that was lost due to its high temperature was investigated in this study. A PV/T system designed to operate with a paraffin-filled thermal tank attached to the PV module was used. Inside the paraffin is a heat exchanger that circulates inside a nanofluid. This design is adopted to cool down the PV module temperature. The study was carried out in the climatic conditions of the month of May in the city of Baghdad - Iraq. The proposed PV/T system’s electrical efficiency was compared with similar systems from the literature. The proposed system has achieved an obvious enhancement as its electrical efficiency was 13.7%.


In this investigation of multi heat pipe induced in heat exchanger shows the developments in heat transfer is to improve the efficiency of heat exchangers. Water is used as a heat transfer fluid and acetone is used as a working fluid. Rotameter is set to measure the flow rate of cold water and hot water. To maintain the parameter as experimental setup. Then set the mass flow rate of hot water as 40 LPH, 60LPH, 80 LPH, 100LPH, 120 LPH and mass flow rate of cold water as 20 LPH, 30 LPH, 40 LPH, 50 LPH, and 60 LPH. Then 40 C, 45 ºC, 50 ºC, 55 C, 60 ºC are the temperatures of hot water at inlet are maintained. To find some various physical parameters of Qc , hc , Re ,, Pr , Rth. The maximum effectiveness of the investigation obtained from condition of Thi 60 C, Tci 32 C and 100 LPH mhi, 60 LPH mci the maximum effectiveness attained as 57.25. Then the mhi as 100 LPH, mci as 60 LPH and Thi at 40 C as 37.6%. It shows the effectiveness get increased about 34.3 to the maximum conditions.


2018 ◽  
Vol 140 (2) ◽  
Author(s):  
Wei Pang ◽  
Yongzhe Zhang ◽  
Yanan Cui ◽  
Hongwen Yu ◽  
Yu Liu ◽  
...  

The increase of operating temperature on a photovoltaic (PV) cell degrades its electrical efficiency. This paper is organized to describe our latest design of an aluminum substrate—based photovoltaic/thermal (PV/T) system. The electrical efficiency of the proposed PV/T can be increased by ∼ 20% in comparison with a conventional glass substrate-based PV. The work will benefit hybrid utilization of solar energy in development of building integrated photovoltaic systems.


2020 ◽  
Vol 12 (22) ◽  
pp. 9520
Author(s):  
M. Imtiaz Hussain ◽  
Jun-Tae Kim

This study summarizes the performance of a photovoltaic/thermal (PV/T) system integrated with a glass-to-PV backsheet (PVF film-based backsheet) and glass-to-glass photovoltaic (PV) cells protections. A dual-fluid heat exchanger is used to cool the PV cells in which water and air are operated simultaneously. The proposed PV/T design brings about a higher electric output while producing sufficient thermal energy. A detailed numerical study was performed by calculating real-time heat transfer coefficients. Energy balance equations across the dual-fluid PV/T system were solved using an ordinary differential equation (ODE) solver in MATLAB software. The hourly and annual energy and exergy variations for both configurations were evaluated for Cheonan City, Korea. In the case of a PV/T system with a glass-to-glass configuration, a larger heat exchange area causes the extraction of extra solar heat from the PV cells and thus improving the overall efficiency of the energy transfer. Results depict that the annual electrical and total thermal efficiencies with a glass-to-glass configuration were found to be 14.31% and 52.22%, respectively, and with a glass-to-PV backsheet configuration, the aforementioned values reduced to 13.92% and 48.25%, respectively. It is also observed that, with the application of a dual-fluid heat exchanger, the temperature gradient across the PV panel is surprisingly reduced.


2014 ◽  
Vol 488-489 ◽  
pp. 1173-1176 ◽  
Author(s):  
Li Qing Tang ◽  
Qun Zhi Zhu

This paper studied the performance of a flowing-over PV/T system with water and Al2O3 nanofluid as the working fluid. The experimental system was built in the outdoors. The parameters of the experiment obtained for processing, analysis, accessing to the electrical efficiency and thermal efficiency. Experimental results show that the flowing-over PV/T system with Al2O3 nanofluid as working fluid has a higher overall efficiency than that with water.


2013 ◽  
Vol 467 ◽  
pp. 522-527 ◽  
Author(s):  
Sakhr M. Sultan ◽  
M.I. Fadhel ◽  
S.A. Alkaff

A new configuration of Photovoltaic/Thermal Collector (PV/T) system has been designed and proposed. The (PV/T) consists of certain layers which are the glass, air gap, PV panel, absorber plate and insulating material layer. In this paper, a glazed (PV/T) solar collector using the spiral flow design absorber has been studied under different Malaysian meteorological conditions. The Performance of outlet water temperature, thermal, electrical and combined (PV/T) efficiencies under two different Malaysian climatic conditions (sunny and cloudy) days have been evaluated. Based on the simulation results, the maximum hourly thermal efficiency of sunny day is 61.3%, while the maximum hourly thermal efficiency of cloudy day is 59.6%. The electrical efficiencies for typical sunny and cloudy days are 12.89%, 13.03%, respectively. The maximum hourly combined (PV/T) efficiency for typical sunny and cloudy days are 74.1% and 72.63%, respectively. As seen from the results, the proposed (PV/T) system design is applicable to be used under different Malaysian climate conditions.


Author(s):  
Wenzhi Cui ◽  
Quan Liao ◽  
Longjian Li ◽  
Songqiang Yu

A dynamic model is developed to analysis the transient characteristics of hybrid photovoltaic/thermal solar energy system. Two typical climatic conditions, clear day and hazy day, are considered in the present study. The daily and annual variation of hot water temperature, electrical output, thermal efficiency and electrical efficiency are calculated and analyzed. The results show that the solar irradiance is the critical factor that affects the variation of the water temperature, electrical output and electrical efficiency of the PV/T system. The thermal efficiency of the system has also a certain relation to the daily fluctuation of solar radiation.


2017 ◽  
Vol 5 (1) ◽  
pp. 1-15
Author(s):  
Zena K. Kadhim ◽  
Safaa Abed Mohammad

This study deals with experimental work implementing to recover the benefit by changing the shape of the tube in heat exchanger (HE) and improving the heat transfer using water as the working fluid. The experimental tests were carried out in build and design a complete test system for counter flow heat exchanger. The tested system consisting of a copper tube with (1m) length (17.05) mm inner diameter (19.05) mm outer diameter, fixed concentric within the outer tube was made of a material PVC. With an “inner diameter (ID) (43 mm) and outer diameter (OD) (50 mm)” isolated from the outside by using insulating material to reduce heat loss. The modify tube was manufacture containing transverse grooves with the depth equivalent to the half thickness of the copper tube. The distance between the grooves on the outer surface of the copper tube is take as a ratio between (0.5, 1) from the outer tube diameter. The laboratory experiment use the hot water at a flow rate ranging between (1-5) LPM, passes in the inner copper tube. As well as the cooling water with the mass flow rate ranging between (3-7) LPM. Three temperatures were the hot fluid are the adoption of (40, 50 and 60) oC and (25) oC the cold fluid. The experiment result showed that the improvement for temperature difference ranging from (14.94 % to 43.2 %) for both corrugated tubes with respect to smooth tube.


Author(s):  
Ryan Crowell

Threats of climate change and depleted petroleum supplies have prompted the need for eco-conscious alternative energy. This paper introduces a ground-breaking concept for harnessing the sun’s power that is significantly more efficient than existing systems. Solar collectors gather the electromagnetic radiation emitted by the sun and heat a propylene glycol to a high temperature that will then transfer the heat to a working fluid (Care30) through a plate heat exchanger. The Care30 then exits the heat exchanger in a gaseous state, and is passed through a Tesla turbine, which in turn rotates a shaft. The shaft is connected to a generator, which transforms the mechanical energy into electricity. The absorption efficiency of the solar collectors allows for mechanical loses while maintaining the overall efficiency at higher levels than any existing PV based system. Ambient temperatures drastically reduce the effectiveness of flat plate solar collectors, cooling the liquids inside before the heat can be efficiently consumed. In contrast, an evacuated tube collector maintains efficiency during such conditions. The collectors are insulated from ambient temperatures by the vacuum pressure inside the tube. A stainless steel flat plate heat exchanger is used to transfer the heat from the glycol/water solution to the refrigerant, which is sent to the turbine after it has been converted to its gaseous state. The solution also provides freeze protection in colder climates. A heat exchanger then cools the gas, returning it to its liquid state, which completes the cycle for the working fluid. The water used in the heat exchanger is then used as a supplementary heating source for the home, for domestic or radiant heating needs. As it is effective even in environments that compromise the functionality of existing PV systems, the proposed system responds effectively to the need for more efficient alternative energy sources.


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