The effect of mass flow rate and solar radiation on the photovoltaic efficiency of a glazed water based PVT

First and second thermodynamic law analyses applied to a solar dish collector

Journal of Non-Equilibrium Thermodynamics ◽

10.1515/jnet-2014-0023 ◽

2014 ◽

Vol 39 (4) ◽

Cited By ~ 8

Author(s):

Vahid Madadi ◽

Touraj Tavakoli ◽

Amir Rahimi

Keyword(s):

Heat Transfer ◽

Solar Radiation ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Exergy Efficiency ◽

Exergy Destruction ◽

Flow Rates ◽

Energy And Exergy ◽

Mass Flow Rates

AbstractThe energy and exergy performance of a parabolic dish collector is investigated experimentally and theoretically. The effect of receiver type, inlet temperature and mass flow rate of heat transfer fluid (HTF), receiver temperature, receiver aspect ratio and solar radiation are investigated. To evaluate the effect of the receiver aperture area on the system performance, three aperture diameters are considered. It is deduced that the fully opened receivers have the greatest exergy and thermal efficiency. The cylindrical receiver has greater energy and exergy efficiency than the conical one due to less exergy destruction. It is found that the highest exergy destruction is due to heat transfer between the sun and the receivers and counts for 35 % to 60 % of the total wasted exergy. For three selected receiver aperture diameters, the exergy efficiency is minimum for a specified HTF mass flow rate. High solar radiation allows the system to work at higher HTF inlet temperatures. To use this system in applications that need high temperatures, in cylindrical and conical receivers, the HTF mass flow rates lower than 0.05 and 0.09 kg/s are suggested, respectively. For applications that need higher amounts of energy content, higher HTF mass flow rates than the above mentioned values are recommended.

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An Unsteady Model for Natural Ventilation with Solar Chimney

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.354-355.286 ◽

2011 ◽

Vol 354-355 ◽

pp. 286-289 ◽

Cited By ~ 1

Author(s):

Zhong Bao Liu ◽

Ya Xin Su

Keyword(s):

Solar Radiation ◽

Mass Flow Rate ◽

Air Temperature ◽

Mass Flow ◽

Flow Rate ◽

Natural Ventilation ◽

Thermal Inertia ◽

Solar Chimney ◽

Air Mass ◽

Peak Value

A one dimensional unsteady mathematical model for predicting the air mass flow rate in a solar chimney has been proposed. The thermal resistance and thermal inertia of both the glass cover and heat absorbing wall were considered in the present model. Crank-Nicolson finite difference numerical method was used to solve the differential equations. The variation of the air temperature in the solar chimney was solved by integrating the controlling equation for the air along the chimney height. Results show the absorber wall reaches its peak temperature 2 hours later with respect to the maximum ambient temperature. The air temperature in the channel varies with the solar radiation in a day and researches its peak value at about 2:00pm. The air mass flow rate increases remarkably with the increase of the channel depth when the solar radiation is higher from 11:00 am to 3:00 pm. The maximum of air mass flow rate occurs at around 2:00pm

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Mathematical Modelling of Single Glazed and Double Glazed Solar Air Heater

International Journal of Innovative Technology and Exploring Engineering - Special Issue ◽

10.35940/ijitee.c8363.0110321 ◽

2021 ◽

Vol 10 (3) ◽

pp. 34-42

Author(s):

Bhawna Agrawal ◽

Pallavi Agrawal ◽

Suman Agrawal

Keyword(s):

Solar Radiation ◽

Mathematical Modelling ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Winter Season ◽

Solar Air Heater ◽

Counter Flow ◽

Heat Gain ◽

Air Heater

This paper focuses on Mathematical Modelling of Single Glazed and Double Glazed Solar air heater (SAH) which is special kind of heat exchanger that transfers thermal energy from the solar radiation to the fluid flowing inside of the collector. The most potential applications of SAH is the supply of hot air for heating of buildings, to maintain a comfortable environment especially in the winter season, air preheating, desiccant refrigeration, and drying of vegetables, fruits, meat, textile and marine products. Solar radiation intensity is less in the morning that increase gradually till noon and again decrease from noon to evening. During simulations it is observed that the heat gain is directly proportional to the mass flow rate. It is maximum for the counter flow SAH and is least for transpired solar air heater. The efficiency of the SAH is directly proportional to mass flow rate. The thermal efficiency is maximum for the counter flow SAH, The useful heat gain increases is highest in the clear days of summer month particularly in the month of April-May and lowest in the cloudy days of winter month particularly in the month of December. The results are in conformation with theoretical aspects.

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Solar Radiation Model Applied to a Low Temperature Evacuated Tubes Solar Collector

Journal of Solar Energy Engineering ◽

10.1115/1.4041402 ◽

2018 ◽

Vol 141 (3) ◽

Cited By ~ 1

Author(s):

Oscar A. López-Núñez ◽

J. Arturo Alfaro-Ayala ◽

J. J. Ramírez-Minguela ◽

J. Nicolás Flores-Balderas ◽

J. M. Belman-Flores

Keyword(s):

Low Temperature ◽

Solar Radiation ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Solar Collector ◽

Outlet Temperature ◽

Radiation Model ◽

Solar Radiation Model ◽

Evacuated Tubes

A solar radiation model is applied to a low temperature water-in-glass evacuated tubes solar collector to predict its performance via computational fluid dynamics (CFD) numerical simulations. This approach allows obtaining the transmitted, reflected, and absorbed solar radiation flux and the solar heat flux on the surface of the evacuated tubes according to the geographical location, the date, and the hour of a day. Different environmental and operational conditions were used to obtain the outlet temperature of the solar collector; these results were validated against four experimental tests based on an Official Mexican Standard resulting in relative errors between 0.8% and 2.6%. Once the model is validated, two cases for the solar collector were studied: (i) different mass flow rates under a constant solar radiation and (ii) different solar radiation (due to the hour of the day) under a constant mass flow rate to predict its performance and efficiency. For the first case, it was found that the outlet temperature decreases as the mass flow rate increases reaching a steady value for a mass flow rate of 0.1 kg/s (6 l/min), while for the second case, the results showed a corresponding outlet temperature behavior to the solar radiation intensity reaching to a maximum temperature of 36.5 °C at 14:00 h. The CFD numerical study using a solar radiation model is more realistic than the previous reported works leading to overcome a gap in the knowledge of the low temperature evacuated tube solar collectors.

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Integrating Transparent and Conventional Solar Cells TSC/SC

Sustainability ◽

10.3390/su12187483 ◽

2020 ◽

Vol 12 (18) ◽

pp. 7483

Author(s):

Moh’d Al-Nimr ◽

Abdallah Milhem ◽

Basel Al-Bishawi ◽

Khaleel Al Khasawneh

Keyword(s):

Solar Cells ◽

Solar Cell ◽

Solar Radiation ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Radiation Spectrum ◽

Photovoltaic Cells ◽

Ambient Air ◽

Negative Side

Conventional photovoltaic cells are able to convert the visible light spectrum of solar radiation into electricity; the unused wavelengths of the solar radiation spectrum are dissipated as heat in the system. On the other hand, certain types of transparent solar cells are able to utilize the rest of the solar radiation spectrum. The integration of transparent solar cells with conventional photovoltaic cells enables the system to absorb and utilize both wavelengths of the solar radiation spectrum. In this paper, two models for integrating transparent solar cells with conventional photovoltaic cells are proposed, simulated, and analyzed theoretically. ANSYS software was used to obtain the results for the proposed models. It is an initial theoretical study that shows some first results; it is almost a work in progress. The results showed that the highest efficiency was for the model that had two cooling spaces. The efficiency was increased as the ambient air temperature decreased and the mass flow rate increased. The percentage drop in photovoltaic (PV) cell efficiency decreased as the mass flow rate increased and the ambient temperature decreased, and it had the lowest value when air/water was used for cooling. The efficiency of the transparent solar cell (TSC) increased as the transparency decreased; in order to have higher efficiency, PV efficiency should be high, with low transparency. When added, the transparent solar cell was supposed to increase the harvested energy due to the utilization of the unconverted solar radiation, but it left two negative side effects. The first negative side effect was the reduction of the transmitted radiation to the conventional solar cell due to the transmissivity of the transparent cell. The second negative impact was the increase in the conventional cell temperature due to the additional thermal resistance, which reduced the effectiveness of cooling the cell from above. The proposed models were verified by comparing the results of the standalone PV that were available in the literature with the two models that are proposed in this paper.

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