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The growth of energy consumption in modern societies has confronted world with threatening changes along with the peril of depletion of fossil resources. Therefore, exploiting the methods of sustainable design has found a high status in international planning and policy making.The most energy consumptions are happening in the building industry, about 40%, and the major part of which is spent for cooling, heating and ventilation. Therefore, using suitable measures to reduce energy consumption has a great influence on energy balance of building. Solar energy for natural ventilation has been used for centuries. Air ventilation is necessary for removing or depleting pollution that can be supplied through solar chimney. Solar chimney is a simple idea to increase natural ventilation in surrounding spaces by using solar energy and chimney effect in an air gap. The driving force in solar chimney is buoyancy force. The solar energy absorbed by chimney causes heat up the air in the chimney so that the air flows upward because of the stack effect. That can be a driving force to enhance natural ventilation. Therefore, the breeze inside the space lets the fresh air enter the space through window. There are a lot of cases which show the use of solar energy for ventilation by some absorption effect in building. The commonest design of solar chimney for ventilation is in vertical form. In the present study, the effect of solar chimney on ventilation rate has been examined in four cities of Iran with different climates. The cities were Rasht (moderate and humid climate), Tabriz (cold climate), Isfahan (hot and dry climate), Bandar Abas (hot and humid climate). Due to the lack of access to the implemented samples, the computerized simulation was used as an alternative method for field studies, the results of which by Energy Plus software in four cities of different climates show that the most suitable city is Isfahan (hot and dry climate) and the maximum ventilation is obtained there. There are also other factors that impacts solar chimney efficiency. Three cities (Isfahan, Yazd, Shiraz) of hot and dry climate were investigated to define their impact of latitude on ventilation rate.

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The building sector is responsible for one-third of global final energy consumption and thus environmental damage, carbon dioxide production. Some reasons for ever increasing building energy consumption : climate change, increase in household electricity load , the growth of real estate, fast-growing household electrical appliances, changes in industrial structure, huge energy consumption of the existing buildings, and the lack of strict government supervision. The world's total energy requirements are mostly used in sectors such as transportation, industry, residence, commerce, etc.. Although most of the energy consumption during the period 1973 to 2009 belonged to the industrial sector, it can be said that the proportion of residential buildings is very high and is increasing rapidly.. World Statistics published by the Department of Energy, United States of America in March 2010 shows that most houses widely use energy for heating and hot water and then cooling and lighting. Therefore, the revision of quality architectural design of buildings, based on the climatic principles , will be very effective in optimizing fuel consumption so that the energy consumption can be controlled wisely and optimally. On the other hand the use of renewable energy technologies can provide energy surplus of buildings and eliminate the problems associated with fossil energy in great extent.Adopting conservation measures on a large scale does allow reducing both electricity and total energy demand from present day levels while the building stock keeps growing. They simulate climate-dependent hourly building energy demands at user-defined scales, typically an individual state or utility zone. Due to the effective role of energy in economic development and its increasing consumption in parallel with the growth of human communities , considering resource constraints and preventing from facing with an energy crisis, the need for conservation through management application is necessary which demands new strategies and approaches in both environmental and architectural revisions for design and building. In particular, the high energy consumption especially in buildings is a major problem in developing countries which has economic and environmental impacts of prime importance while it is considered to be the most significant cornerstone of growth in different dimensions. Buildings , it is statistically shown, account for a third of total global energy consumption. Energy consumption in buildings is increasing due to several factors including climate change, increasing electrical energy consumption in households, real estate development, diversity of modern appliances, changes in industry structure, very high energy consumption in existing buildings and the lack of adequate supervision of the state.. Therefore, efforts must be focused on the control and management of energy consumption . The purpose of energy management is reducing energy consumption in a way that is logical and economical and can cause no negative effects on welfare and thermal comfort. So, a focus for building energy consumption efforts is of great importance. The occupant behavior and building manner can both increase the building energy consumption, especially residential ones.In the building quality part, there are many techniques affects on building energy consumption, which divide to passive and active. The passive ones are the techniques that related to the body and design of a building as material, utilization of solar radiation on the bodies, length and width of building, insulation, window, and so on without electrical or other energy portfolio, but the effect of these parameters was not equal. Therefore, this study presents an approach to determine the effect of main parameters of some of the building techniques on energy consumption. In this study, these parameters were identified and evaluated and finally were Prioritized. Not all of the parameters has equal role on energy consumption, which the mentioned weights indicated. The remainder of the paper organized as follows. Firstly, the parameters were identified by research and interview. The effective parameters recognized as the alternatives of the mentioned hierarchy3 step trees, which can be listed as follows: occupants; built area; Step No.; Proximity degree; Window to wall ratio; Length to width ratio; Side. Secondary, the questionnaire performed and completed by experts as architects, mechanical engineers and energy engineers. Analytic hierarchy process (AHP) and its applications in surveys related to buildings were presented. Up to now, the AHP method has been widely applied in the general policymaking in buildings. Next, the effective parameters on energy consumption evaluated, and in next section the AHP for the approach concernedexplained and resultsoffered. Finally, the last Section includes the concluding remarks. The weights and priorities of the effective parameter are illustrated. As a result, considering weight of factors in building designing process, the different parameters of BO can be classified and evaluated: First, the main effective parameter is window to wall ratio. Depends on the weight of this parameter (0.36), the window area and materials are important for building designers. Another main parameter is side no., if a building has 1 or 2 or 3 or 4 side, its energy consumption differs fundamentally. Choosing the main direction, side and the side no. are all associated. One of the main results is about the building area depending on energy consumption, which considers having the main role, but in present survey concluded that the third effective parameter is area. The least effective parameter is occupant number, due to energy load of building space and quality, not building occupant. Urban designers and Architects considering Building Orientation (BO) and its parameters can design buildings that are energy efficient. If building orientation )BO( is considered, solar radiation absorbed by the surface structure of the building will become more favorable, and consequently the energy consumption will be reduced. However, if the building orientation (BO) is considered along with climatic factors, there will be direct effect of increased energy costs. In addition , urban designers must greatly pay attention to building sides while determining the building blocks as the transmitting surfaces are from outdoor to indoor in summer and vice versa in winter. Architects must also pay attention to different ratios of windows to create the proper ratio of heat transfer in the buildings. The materials used in the buildings are of great importance.

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A new once-through air solar collector was modeled and tested. In this solar heater a transpired absorber was used. The cover of the collector was double glazed and consists of many slats and assembled in such a way that it formed a stair step fashion and made many slots through which inlet air was sucked into the collector. The sucked air is be-lieved to recover part of the sort wavelength radiation absorbed by the glass sheets. Fur-thermore, the long wavelength emission from the transpired absorber was trapped by the double glazing cover and could also be captured by the air thus reducing total heat loss. A mathematical model was developed to predict the effects of variations in the input pa-rameters on the collector thermal efficiency. The theoretical results showed that the thermal performance of the collector was sensitive to air flow rate, ambient temperature, solar irradiance, absorber emissivity variations, Slat length and slot height. The collector was tested under a solar simulator over a wide range of air flow rates. The experimental results were in good agreement with the theoretical values. An absorbing efficiency as high as 82% could be obtained. Since the air heater was once-through, it is very suitable for grain drying purposes.

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Research subject: Solar energy is a renewable resource that is abundant and can solve many problems of energy shortage. In order to use solar energy to desalinate water and produce high quality steam, one of the cheap and commercially proposed structures is floating solar steam generation system. In this system, water is transferred to the surface of the system in a controlled manner and is converted to steam using the heat generated in the photothermal layer. There are generally four main challenges in solar steam generation systems. These challenges include managing and preventing heat loss, structural strength, managing and transferring water within the structure, absorbing light and converting light into heat.
Research approach: In this paper, floating multilayer solar steam generation systems were fabricated in which porous polyurethane foam was used as the substrate and thermal insulation layer. Moreover, felt was used as the water-transfer layer. Photothermal materials including graphite, gold, and mixtures of graphite and gold were used as the light-absorbing layers to produce high-quality steam. Also, in order to determine the water evaporation rate and the efficiency of the systems, the amount of changes in water mass and system temperature has been measured.
Main results: Among the different solar steam generation systems studied, the system made of graphite-gold mixture absorber is able to produce steam at a rate of 1.257 kg.m^-2.h^-1. This rate is equivalent to an efficiency of about 82%. To evaluate the performance of the systems in more real situation, they were tested using seawater. As resulted, the rate of evaporation of seawater by the graphite-gold mixture system is 1.201 Kg.m^-2.h^-1 and its efficiency is 78.4%.

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Research Subject: Because of the constant deterioration of environmental conditions, the world faces energy and clean water shortage. To address the water crisis issue, the solar steam generation system has been considered as a suitable technology for seawater desalination due to its competitive features, such as no carbon dioxide emission, low energy consumption, and high efficiency. In modern solar steam generation systems, solar energy is harvested by a photothermal absorber and then converted into thermal energy to heat a certain volume of water and produce steam. Then, the generated steam condenses on the inner surface of the cover, and clean water is collected. The five key features required for solar steam generation system are: high light absorption, low heat losses and heat localization, proper water transfer, and the ability to float on the water surface.
Research Methods: In this study, a solar steam generation system based on a graphite absorber layer is built, and its performance is improved using nickel plasmonic nanoparticles.
In order to investigate the dependency of the performance on the structure, two different layers including cotton and polyester felts are used to transfer water controllable. In this study, the water evaporation rate, surface temperature, and efficiency of the devices are evaluated.
Main Results: Thermal efficiency and evaporation rate for the system based on the pure graphite absorber is 68.17% and 0.97 kg/m².h, which increases to 93.57% and 1.37 kg/m².h, respectively by adding nickel nanoparticles. Using two cotton and PS water managers reveals the importance of the thermal energy and mass transfer balancing in the systems, which strongly affects the devices performance.

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  In order to increase the heat efficiency of solar driers a shelf type solar dryer with two collectors was designed and constructed in Agriculture Research Center of West Azarbaijan, and used to dry tomatoes slices. This experiment was conducted by complete randomized factorial experimental design in 2 factors and 4 replicates. The first factor was pretreatment in 3 levels, without pretreatment (control), dipping in boiling water for 15 second and dipping in 2/5% boiling brine for 10 seconds and second factor was drying method in two levels, open sun drying and shelf type solar dryer. The analysis of the results showed that average temperature of inside of the solar dryer in first and second years were 9/5  and 12 higher than the average ambient temperature respectively. The results also showed that in the first year the moisture contents of dried tomatoes produced using solar dryer was about 25% the lower than that produced by open sun drying, while in second year moisture contents were not significantly different. Also blanched slices in 2/5 % boiling brine had little damage, more rehydration ratio and better color in comparasion with other treatments. The percentage of damage and contamination of the sliced produced using solar dryer was reduced by 40% in comparison with. The samples dried in open air. Therefore according to the results obtained, it is recommended to blanch slices with 2/5 % boiling brine solution for 10 seconds to get a better results.  

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Saffron is the most expensive agricultural product and like other products, is affected by some limiting factors, including soil pests such as bulb mite Rhizoglyphus robini Claparede (Acari: Acaridae). Due to its polyphagous habit, it remains in the soil for a long time and is one of the most important pests of saffron. To determine the effect of non-chemical management factors including soil solarization days, fertilization and year on the population of bulb mite and yield of saffron, a split-plot experiment based on a randomized complete block design in three replications was conducted between 2007 and 2011 in Gonabad, Iran. Fertilization (Cow manure) of zero, 20 and 40 t/ha as the main plots and soil solarization of zero, 10, 20, 30 and 45 days as sub-plots were studied for four years. The results showed that simple and interaction effects of the three factors including year, fertilization and soil solarization days on the population of bulb mite and saffron yield were significant. Simple linear regression was fitted between the population of bulb mite and saffron yield as well as multiple linear regression for population of bulb mite and saffron yield separately. The population of bulb mite increased during the experiment by increasing the two factors of the year and fertilization separately. Whereas, with increasing soil solarization days, population of bulb mite decreased except for 10 days solarization treatment and, unexpectedly, in 45 days of solarization treatment, the population increased in the fourth year.
 
 

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Solar energy can be utilized through different types of passive and active solar systems. One of the passive systems is the Greenhouse that provides different functions. In this research, heating performance of Greenhouse in cold climate is simulated, investigated, and analyzed by means of computer software. The results of this research showed that Greenhouse, in comparison with Direct Gain glazing system, decreases building heating load, despite the diminution of the direct radiation gains. In Ardebil, the optimal building orientation, in order to get the maximum solar gain and the minimum load in the heating period, is obtained in south west and west direction of the facade. The maximum heat loss and minimum solar gain occur through the north side of the building, which is considered as the most inappropriate facade direction for the Greenhouse system.

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Many research studies have been performed on forced convection (active) solar dryers for fruit and vegetables. A short survey of these showed that applying the forced convection solar dryer not only significantly reduced the drying time but also resulted in many improvements in the quality of the dried products. Active indirect and mixed-mode thin layer solar drying experiments were conducted on Sultana grapes. A combination of a solar air heater and a cabinet dryer was designed, constructed and tested for this product in the Agricultural Engineering Department at Shiraz University, Iran. Three air flow rates (0.085, 0.126 and 0.171 m3 s-1) and two types of drying systems (indirect and mixed-mode) were adopted. The south wall of the drying chamber was covered by a sheet of glass for mixed-mode and the glass sheet was covered with a thick sheet of cloth for an indirect solar drying system. Seven well-known thin layer drying models were used separately to fit the mixed-mode and indirect type experimental data for Sultana grapes. For experimental indirect data, the Modified Page model (r= 0.998, χ2= 0.000241) and for experimental mixed-mode data, the Page model (r= 0.999, χ2= 0.000169) showed the best curve fitting results with highest r (correlation coefficient) and lowest χ2 (reduced chi-square) values. The constants in these models explain the effects of drying parameters, air velocity and temperature. To take account of these effects, the best correlation equations between the constants and drying parameters were also introduced using multiple regression analysis.

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A thin layer solar drying method was compared with a traditional method (sun drying) of paddy drying, with their effects on quality characteristics of two varieties of Iranian rice (Kamphiroozi and Sazandegi) studied. Solar drying process was conducted in a passive, mixed mode type solar dryer at about 50ºC for 90 minutes. In sun drying method this process took 8-10 hours at a mean temperature of about 26ºC. Samples were milled and polished. Quality factors including trade quality (head rice yield percent and whiteness), cooking quality (amylose content, gelatinization temperature, gel consistency, aroma and flavor) as well as nutritional quality (thiamine and lysine contents) were evaluated. For a determination of head rice yield, the percentages of de-husked and broken kernels were determined by hand-sorting of broken kernels, the calculation being done through the pertaining formula. Gel consistency was determined according to the method of Cagampang et al. (the consistency of milled rice paste that has been gelatinized by being boiled in dilute alkali and then cooled to room temperature). Amylose content was determined through the simplified assay method of Juliano (setting standard curve by spectrophotometer and comparing the adsorption with the sample’s). Gelatinization temperature was estimated by the extent of alkali spreading and clearing of milled rice soaked in 1.7% KOH for 23 hours at room temperature. Organoleptic characteristics of cooked rice (iflavor, aroma) and apparent whiteness were judged by the taste panel using sensory evaluation method in triplicate. With respect to nutritional value, lysine amino acid was determined by using biological assay and applying Lactobacilllus delbrueckii while thiamine being measured through thiochrome fluorescence technique. The objective of this study was to examine the influence of solar drying process on the final quality of rice kernels and to compare the effects of this method with those in the traditional method of drying (natural sun drying). Results indicated that under the conditions prevailing in solar dryer, quality factors weren't affected except for whiteness of rice that too was better than that for sun dried samples. All other quality characteristics of the final product were acceptable in comparison with those in sun drying method.

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This article presents a transient model of a solar adsorption cooling system. A computer program is developed to simulate the operation of a two-bed silica gel- water adsorption cooling system as well as flat plate collectors and the hot water storage tank. This program is then utilized to simulate the performance of a sample solar adsorption cooling system used for cooling a set of rooms that comprises an area of 52 m2 located in Ahwaz city in Iran. The results include the temperature profiles of hot, cooling and chilled water in addition to adsorption/desorption beds, evaporator and condenser, collector hot water temperature, auxiliary heater fuel consumption and solar fraction of the system. Furthermore, the effect of the cycle time on COP (coefficient of performance), SCP (Specific Cooling Power), refrigeration capacity, fuel consumption and solar fraction is studied. The results show that the cycle time increases COP and SF of the cycle but decreases cooling capacity and supplementary heater fuel consumption.

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Outdoor experiments on a once-through single glazed solar air heater with perforated metal absorber plate were conducted to determine the practical effect of absorber plate porosity as well as suction air flow rate on the collector thermal efficiency and its total pressure drop. Three aluminum absorber plates were made perforated by drilling circular holes with different diameter/pitch ratios in square layout. A fan was employed at the top of the collector to suck ambient air from the bottom side through absorber plate perforations. The flow channel was designed such that uniform air flow over the entire absorber plate area could be achieved. Five levels of air mass flow rates (0.0065 to 0.0321 kg m-2 s-1) were adopted. Pressure drop across the apparatus was measured. The inlet air was preheated by short wavelength radiation absorbed by the cover as well as the long wavelength emission by the absorber prior to catching the heat from transpired absorber plate. A maximum thermal efficiency of 84% could be achieved for the most part of the porous absorber plate at the highest air mass flow rate. The collector with minimum porosity showed a maximum pressure drop. In some experiments, the glass cover was removed to determine the outdoor effect of glazing. Comparing the performance of the collector with and without glazing showed that the unglazed collector was about 25% less efficient than the glazed one at the same overall operating conditions. This reduction can be attributed to high top radiative and convective heat losses for the unglazed collector at the outdoor conditions. The pressure drop for the uncovered collector showed a lower magnitude in comparison to the covered one. The inlet air passes and heats up (21-59°C above the ambient) through the solar collector, therefore the fresh and clean hot air can be continuously supplied for many purposes such as solar drying system.

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In this research a new laboratory solar-vacuum dryer was designed and fabricated to study drying behavior of pomegranate arils with heat source of solar energy. Drying of the samples was implemented at the absolute pressures of 10, 20, 40 and 60 kPa. Impact of different absolute pressures on moisture loss trend, effective moisture diffusivity, color and shrinkage of pomegranate arils, dried in solar-vacuum dryer was studied. With regression analysis of the applied models, proved that the Midilli model had supremacy in drying behavior prediction of pomegranate arils. Results indicated that with decreasing absolute pressure, drying time was decreased. Minimum drying time was related to the absolute pressure of 10 kPa. Effective moisture diffusivity of the pomegranate arils was estimated at the ranges of 3.09×10^-10 to 4.13×10^-10 m²/s.Total color changes and shrinkage percent of the pomegranate arils were estimated at the ranges of 17.4 to 22.1 and 67.58% to 74.45%, respectively.    

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Photonic crystals (PCs) with extraordinary optical properties, can be used to enhance light absorption and improve solar cell’s conversion efficiency. Prohibition of propagation for some particular wavelengths of light in PCs result in increasing the path length of light in working electrode of solar cell that enhance the probability of photon absorption. In our work, we present a two-step anodization method for manufacturing the dye-sensitized solar cells (DSSCs), having a three-dimensional roughness material as working electrode that looks like a semi-photonic crystal mesoporous structure. This approach is a facile one to produce a PC-like structure and it plays a great role in improvement of output power of DSSC. Measurements show that solar cell’s photovoltaic conversion efficiency based on this 3D roughness structure is higher than the conventional DSSC.

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To increase agricultural crops’ quality and to minimize losses in the final product and used energy during the drying process, major drying system parameters should be continuously controlled. Precise control of such parameters is attained by using automatic control systems. To optimize the overall dryer efficiency in a forced convective solar dryer, a controller was designed, constructed and evaluated. The dryer fan speed was chosen to be the controlled variable. Based upon the mathematical relations and a monitoring of the air inlet temperature to the collector, the air outlet temperature from the collector and the air outlet temperature from the drying chamber, the dryer efficiency was determined. Using the dryer control program the current and the optimized dryer efficiencies were calculated, compared and the fan speed changed accordingly to maintain the optimized efficiency. Experiments were carried out in three replications (in three days) with the results showing that the system was capable of controlling the fan speed to obtain the optimum efficiency. The dryer equipped with the designed control system worked with its highest efficiency throughout the day. Statistical analysis showed that the control system highly improved the dryer efficiency throughout its operation at a 1% probability level.

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In this study design, construction and test of a solar bread cooker has been undertaken for solar radiation status in Kashan. In design step and in order to produce the required energy, use of a parabolic reflective surface for concentrating the solar flux on the back of a cooking plate was considered. For cooking thin bread with 45 cm diameter the diameter of the reflective surface was calculated 130 cm and the cooking plate diameter and thickness were considered 48 cm and 6 mm, respectively. Since the sun orientation changes with time the reflective surface became capable of being adjusted around a north-south as well as east-west axes; also it may be moved vertically up or down. For evaluating the performance, tests and measurements were performed on different days of summer, 1391. The results indicated the validity of calculations and showed the overall efficiency of the solar bread cooker is around 50%. With the solar cooker it is possible to cook 12 beards per hour each with 200 gr weight of dough in eight months of the year at least for six hours in every sunny day; also it may be used for cooking other foods.

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In this research drying kinetics, moisture diffusivity and determination of most appropriate mathematical modeling and activation energy of Mazafati dates species were studied under a cabinet solar dryer.Drying experiments were carried out at three air temperatures of 50, 65, and 80ºC and three air velocities of 1.0, 1.5, and 2.0 m/s. Effect of temperature and air velocity evaluated on drying time and shrinkage by using a completely randomized statistical design. Results showed that the effects of temperature and air velocity are significant on drying time. The average increase of temperature from 50ºC to 80ºC caused the drying time to decrease by 70.77%. For determination of most appropriate model, the highest value of R² and the lowest values of c² and RMSE were used. For mathematical modeling, eight empirical models were fitted on experimental data and the best model was selected. The result of regression analysis showed that Page model has the best fitting with data. Moreover, the lowest and highest value of moisture diffusivity were obtained as 4.309×10^-10 and 0.0188×10^-9  m²/s at temperatures of 80^°C and 50^°C, respectively. Also the values of activation energy in the drying of Mazafati dates species were found between 31.22 to 42.27 kJ/mol.  

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Solar field transfer heat of solar radiation to the heat transfer fluid. Appropriate size of solar field is one of the most important parameters in levelized cost of solar electricity. In this paper optimum solar field size in an integrated solar combined cycle is determined. Furthermore, an algorithm is presented for the simulation of parabolic trough solar collector performance. Four solar fields by different size but same power block are considered. Thermal performance of each field in terms of nominal and partial load conditions is studied. Solar field and combined cycle are simulated by coding in EES software. According to The hourly meteorological data, electricity generated for a year is calculated. Levelized cost of solar electricity for each field size is calculated and optimum size of the field is selected. According to the economic analysis, the optimum solar field size in an integrated solar combined cycle is depended to location of plant, HRSG power demand, and the constraints of the power block and solar field.

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In this paper, the performance evaluation of a two-way hybrid photovoltaic/thermal (PV/T) solar collector was analytically and experimentally carried out. Mathematical expressions for operating parameters in glass to glass and glass to tedlar PV/T solar collectors were developed and experimentally validated by a glass to tedlar PV/T solar collector system. Also the influence of air flow rate on the solar collector performance was investigated. The results showed that the glass to glass PV/T solar collector gave higher outlet air temperature, cell temperature and thermal efficiency than the glass to tedlar PV/T solar collector. However, back surface temperature and electrical efficiency were higher in case of glass to tedlar collector. Increasing the air flow rate led to a lower outlet air temperature and a higher electrical efficiency of the photovoltaic module. Maximum experimental electrical efficiency, thermal efficiency and overall thermal efficiency for the glass to tedlar PV module were found to be 10.35, 57.9 and 84.5%, respectively.