Thermal Efficiency Of Solar Collector Research Articles

A thermal efficiency-enhancing strategy of parabolic trough collector systems by cascadingly applying multiple solar selective-absorbing coatings

For a long time, the pathway for enhancing solar collector thermal efficiency of solar energy converting into heat has been blocked because state-of-the-art parabolic trough collectors (PTCs) suffer low thermal efficiency from severe reradiation heat loss. Based on the nonuniformity temperature distribution in the parabolic trough collector loop, a novel strategy of cascadingly applying multiple solar selective-absorbing coatings (SSCs) in different sections of the collector loop is proposed. Two systems were considered to implement the designed strategy: an ideal system with multiple ideal SSCs with related optimal cutoff wavelengths at various temperatures; and a multi-section system with multiple practical SSC materials. By setting up a two-dimensional heat transfer model, the thermal performance of the PTC systems was analyzed. The results showed that the ideal and the multi-section system had better thermal performance than a conventional system. The heat loss of the multisection system was reduced by 29.3%, and the thermal efficiency was enhanced by 4.3% with an operating temperature of 290–550 °C. This strategy is expected to provide a new possibility for the realization of cost-effective solar energy utilization.

Improving the Thermal Efficiency of Flat Plate Solar Collector Using Nano-Fluids as a Working Fluids: A Review

Solar energy is one of the most important types of renewable energy and is characterized by its availability, especially in Iraq. It can be used in many applications, including supply thermal energy by solar collectors. Improving the thermal efficiency of solar collector leads to an increase in the thermal energy supplied. Using a nano-fluid instead of base fluid (water is often used) as a working fluid is a method many used to increase the thermal efficiency of solar collectors. In this article, the latest research that used nano-fluid as a working fluid in evaluating the thermal efficiency of solar collector, type flat plate was reviewed. The thermal efficiency improvement of flat plate solar collector was reviewed based on the type of nanoparticles (metal oxides, semiconductors oxides, carbon compounds) used in the base fluid and comparison was made between these nanoparticles under the same conditions. Moreover, the effect of varying the concentration of nanoparticles in the base fluid and changing the working fluid flow rate on the thermal efficiency of flat plate solar collector was also reviewed. The results of the review showed that nano-fluids containing carbon compounds are better than other nano-fluids and that copper oxide is better than the rest of the metal oxides used in improving the thermal efficiency of flat plate solar collectors.

Thermal Performance of Nanofluid Flow Inside Evacuated Tube Solar Collector

Solar collectors are systems for absorbing the sun's radiant energy and converting it into heat. The working principle of solar collectors are relying on the solar radiation incident upon the transparent surface, and the collected radiation heat is stored within the operating fluid. However, the conventional operating fluid is less than satisfactory in term of promoting the thermal efficiency of solar collector. Consequently, the aim of this paper is to investigate the use of nanofluid as an operating fluid in a single end evacuated solar collector. The expectation is that the flow behavior of nanofluid can lead to the improvement of thermal efficiency of solar collector. The design of solar collector is carried out using Gambit software and the heat transfer characteristics are simulated by nanofluid flow with 1%, 3% and 5% volumes by ANSYS Fluent software. The results demonstrate good agreement with existing experimental results. The numerical analysis shows the improvement of collector performance compared to pure water fluid. The results show that by increasing the nanoparticles volume fraction the efficiency of the collector improves significantly.

Improvement of Heat Pipe Solar Collector Thermal Efficiency Using Al2O3/Water and TiO2/Water Nanofluids

Heat pipe solar collectors (HPSCs) are heat exchangers that carry heat based on the phase change of the heat pipe working fluid. It is aimed to increase the operating temperature range of solar collectors by changing the phase of the working fluid in the heat pipe at low temperature. For this reason, it has become widespread to use nanofluids obtained by mixing nanosized metal oxides with the base fluid in certain proportions in order to increase both the thermal conductivity of the heat pipe working fluids and to increase the specific heat closures. The main purpose of this study, which was conducted to evaluate the performance of HPSCs, is to increase performance, and an experimental study has been conducted in this direction. For this purpose, an HPSC designed and manufactured was used. Al2O3-water and TiO2-water nanofluids containing 2% nanoparticles were used in order to increase performance in the study. HPSC used in the study consists of 8 heat pipes with a length of 100 cm. The experiments were carried out for pure water and nanofluids, and their efficiency and strength were compared. The highest value of instantaneous efficiency was calculated as 48% when pure water was used as the working fluid, 58% for Al2O3-water nanofluid, and 64% for TiO2-water nanofluid. The instantaneous power obtained using pure water was determined as 135.66 W, 167.96 W for Al2O3-water nanofluid, and 184.03 W for TiO2-water nanofluid. The improvement in efficiency was determined as 20.8% for Al2O3-water nanofluid and 33.3% for TiO2-water nanofluid. Improvement in powers was found to be 23.8% for Al2O3-water nanofluid and 35.6% for TiO2-water nanofluid.

A novel integrated system for sustainable generation of hydrogen and liquid hydrocarbon fuels using the five-step ZnSI thermochemical cycle, biogas upgrading process, and solar collectors

The utilization of renewable energy sources such as solar energy and biogas have recently received more attention due to a decline in fossil energy sources and environmental issues. A leading method for long-term renewable energies sources storage is to convert to fuels such as hydrogen and heavy value hydrocarbons. In this work, a novel integrated structure is developed for sustainable cogeneration of hydrogen and heavy liquid hydrocarbon fuels. This integrated structure consists of the zinc-sulfur-iodine thermochemical cycle, biogas treatment cycle, Fischer–Tropsch synthesis reactions, a carbon dioxide power generation, and solar dish collectors. It is demonstrated that this integrated structure produces 359.8 kmol/h hydrogen, 116.8 kmol/h liquid fuels, 1714 kmol/h carbon monoxide, and 289,149 kmol/h hot water. The thermal energy and exergy efficiencies of the integrated structure are 58.03% and 44.34%, respectively. The exergy analysis illustrates that exergy destruction mostly occurs in heat exchangers (36.67%), reactors (24.69%), and collectors (20.25%). The sensitivity analysis demonstrates that the absorbed useful energy and solar collector thermal efficiency decrease up to 9.735 kW and 0.7751, respectively when the average operating wall temperature in each solar collector increases from 627 °C to 1127 °C. The thermal efficiency and productivity of the liquid fuels increase up to 0.63 and 383.6 kmol/h, respectively with increase of carbon dioxide composition in the biogas from 40 mol% to 55 mol%.

Effect of Fluid Flow Direction on Charging of Multitube Thermal Energy Storage for Flat Plate Solar Collectors

Flat plate solar collector plays a significant role in domestic water heating due to the ease of operation and maintenance. Thermal energy storage with phase change materials is used to store heat energy. The thermal performance of paraffin wax-based multitube latent heat storage with a flat plate solar collector is investigated experimentally. The present work focuses on the fluid flow direction for charging and discharging in a vertical multitube-based thermal storage unit. The charging process took about four hours, with a fluid flow rate of 0.02 kg/s at about 70°C. The flat plate solar collector's thermal efficiency is 56.42% for the fluid flow rate of 0.02 kg/s at the average solar radiation of about 600 W/m2. During the discharge process, there was an increase in water temperature by 40°C at a fluid flow rate of 0.01 kg/s in 30 minutes. The 25-liters of water is circulated to discharge the stored heat. The heat storage effectiveness is varied between about 0.4 and 0.75. During the discharge, the flow of water from the center to the periphery showed about a 1.7% higher temperature than that of the water from the periphery to the center. For charging the heat storage, the preferred fluid flow mode is from the periphery to the center. The employment of latent heat storage with a solar collector is beneficial for our thermal needs after sunshine hours.

Energy, exergy and economic analysis of liquid flat-plate solar collector using green covalent functionalized graphene nanoplatelets

• Thermal efficiency of solar collector increased using eco-friendly nanofluids with maximum improvement up to 24%. • Exergy efficiency increased with weight concentration of eco-friendly nanoparticles. • Maximum increase in friction factor was around 7.9% for 0.1% nanofluid than base fluid. • Relative pumping power slightly increases with increment in nanofluid concentration but is quite close to that of the base fluid. • Pay back period was 5.615% lesser using nanofluids than water. The conventional method of synthesizing carbon-based nanofluids produces harmful products that are highly toxic and hazardous. The present investigation deals with the effects of using eco-friendly, non-corrosive, covalent functionalized Graphene Nanoplatelets with gallic acid (GGNPs) as heat transfer fluid on energetic and exergetic performance of a Liquid flat-plate solar collector (LFPSC). Long-term dispersible stable GGNP nanofluids with base fluid distilled water are prepared with different weight concentrations of 0.025%, 0.05% & 0.1%. For varying concentrations, fluid flow rates of 0.8, 1.2, and 1.5 L/min, heat flux intensities of 600, 800, and 1000 W/m 2 , and inlet temperature ranging from 303 to 323 K are considered for the conduction of experiments. Improvement in energy and exergetic efficiency was achieved using GGNP nanofluids. Thermal efficiency surges with increment in flow rate and heat flux intensities, meanwhile it decreases for increment in inlet temperature. The maximum enhancement in LFPSC efficiency is 24.09% for 0.1 wt% GGNPs and flow rate of 1.5 L/min than distilled water. Analysis of exergetic performance revealed that exergy efficiency reduces with a rise in mass flow rate meanwhile enhanced with an increase in nanofluid concentration. Exergy efficiency was maximum for 0.1% GGNP concentration and flow rate of 0.8 L/min. The maximum increase in friction factor values is approximately 1.5, 2.6 and 7.9% for 0.025, 0.05 and 0.1% GGNP nanofluids than distilled water. Relative pumping power slightly increases with the increment of GGNP concentration but is quite close to that of the base fluid. Performance index greater than one is obtained with higher values achieved at an increase in GGNP weight concentration. Economic consideration of GGNP nanofluids in LFPSC showcased a maximum reduction of 26.41% in the size of collector area using 0.1% GGNP nanofluid instead of distilled water. The payback period for LFPSC using GGNPs was 5.615% lesser than that of using water.

Effect of different nanofluids on performance analysis of flat plate solar collector

Flat plate solar collectors are widely utilized for water heating in residential buildings, commercial and industrial applications. The thermal characteristics improvement of the working fluid can dramatically increase solar collector thermal efficiency. The working fluid thermal properties were improved by using nanofluids. Present work aims to study the effect of nano aluminum and titanium oxides addition to the water as a working fluid on solar collector efficiency. Outdoor experiments were carried out according to ASHRAE Standard 86 − 93. Nanoparticles of 25 nm size were used to reduce the agglomeration and increase the dispersion. Nanofluids were prepared at a concentration of 2% by weight and a surfactant was added to improve the stability. The tank outlet temperature was measured at different nanofluid flow rates of 2, 4, and 6 l/m. The maximum increases in tank outlet temperature for Al2O3 and TiO2 were 5 and 7% at a flow rate of 2 l/m, respectively. Al2O3 and TiO2 nanofluid improved the collector efficiencies by 30 and 32% at 2 l/m, respectively. TiO2 had an increase in collector efficiency about Al2O3 at all flow rates. The maximum improvements in thermal conductivity for TiO2 about Al2O3 were 1, 2, and 2.5% at 2, 4, and 6 l/m flow rates. The increases of friction coefficients of the nanofluids were less than 1% at all temperature range. The maximum increase in collector efficiency for Al2O3 and TiO2 were about 22 and 30%, respectively about base fluid. Using Al2O3 and TiO2 nanofluid was recommended to enhance solar collector performance.

Conversion and storage of solar energy in the forms of liquid fuel and electricity in a hybrid energy storage system using methanol and phase change materials

The utilization of solar-assisted hybrid energy systems is an appropriate way to generate green power. To this aim, an innovative hybrid charging/discharging system comprised of solar dish collectors, methanol synthesis unit, power cycles, and carbon dioxide liquefaction process as well as phase change materials, is introduced and thermodynamically assessed. An ammonia/water absorption refrigeration cycle is applied for the carbon dioxide liquefaction process. The proposed structure is simulated by using HYSYS, TRNSYS, and MATLAB, and a thermodynamics framework is conducted to assess the integrated system performance. The proposed structure successfully produces 8.449 kg/s and 11.49 kg/s of methanol liquid carbon dioxide, respectively. Energy analysis of this integrated system indicates that, the overall thermal efficiency of the charging and discharging modes are 0.8486 and 0.4076, respectively. The results of exergy evaluation reveal that the largest exergy destruction in the charging and discharging modes are related to collectors with 34.07% and reactors with 56.58%, respectively. In addition, the overall exergy efficiency of the charging and discharging cycles are 57.11% and 42.32%, respectively. A comparison between the proposed system and similar works show that the energy efficiencies of the power cycles are higher than similar studies. Finally, sensitivity analyses on the influence of various parameters such as useful energy collected by collectors, stored heat of phase change materials, solar collector thermal efficiency, irreversibility, and exergy efficiency in the cycle and collector are performed.

Comparative and performative investigation of various data-based and conventional theoretical methods for modelling heat pipe solar collectors

Solar collector, as the key component of any solar system, has always been the focal point of research in the field of solar energy. Based on the literature, data-based methods, which have been proven to be promising in accurate modelling of solar collectors, have not been used for modelling heat pipe solar collectors (HPSCs). At the same time, accurate equations relating the thermal efficiency of solar collectors to the operational and climatic conditions have not been obtained for HPSCs. Therefore, in this study, various data-based and energy balance-based modelling methods were proposed, and based on different accuracy criteria, their precisions were compared in predicting the performance of HPSCs. First, an experimental rig was manufactured and the operational data of the system was recorded throughout a year. The recorded experimental data was used to train and validate various modelling approaches. Then, the accuracies of the proposed models were analysed and assessed. The evaluated models included Artificial Neural Network (ANN), Thermal Resistance Network (TRN), Artificial Neuro Fuzzy Inference System (ANFIS), and Fuzzy methods. Among different modelling approaches, ANN had the best performance which was followed by the ANFIS and TRN methods. The Fuzzy method was not recommended due to its poor accuracy. In addition, the optimum equations relating the outlet temperature of HPSCs to the operational conditions of the solar water heating systems as well as the climatic conditions were obtained and verified.

Study of Effects of Dimensionless Parameters on Thermal Efficiency of Enhanced Solar Liquid Collector with Coiled Wire Inserts

Solar liquid collectors are good candidate of heat transfer enhancement. The efficiency of a solar liquid collector can be improved by augmenting tube side heat transfer using enhanced techniques used in heat exchangers. Various types of heat transfer enhancement techniques has been used in heat exchangers which are mainly classified in two types, active and passive techniques. Solar liquid collectors can also be enhanced by these active and passive devices. Passive techniques, mainly swirl flow devices are more popular enhancement techniques in solar liquid collectors as they do not require any external source of power and also they do not affect the mechanical strength of tube material. Initially twisted tape inserts and conical inserts were popular passive devices used in enhanced solar liquid collectors mainly because of availability of established correlations. Wire coil inserts are relatively less experimented passive technique. This study is focused on tube side heat transfer augmentation of a solar flat plate liquid collector by wire coil inserts and effect of various dimensionless parameters on thermal efficiency of solar collector.

Development of a solar colleсtor based on aluminum construction heat pipes

The object of research is the thermal efficiency of solar collectors based on aluminum structural heat pipes. Solar collectors with heat pipes have a structurally similar design. The heat-absorbing panel secures the heat pipes to the evaporation zone, and the condensation zones are located in the battery tank. The differences are only in the designs of the absorption panels, the areas of the condensation zones and the heat carriers of the heat pipes. One of the most problematic places of research is the justification and development of a new design of a heat-absorbing solar collector panel based on heat pipes.A review of the publications showed that a solar collector based on aluminum structural heat pipes operating in the two-phase thermosyphon mode has a heat loss when transmitting radiation heat exchange in the long-wavelength range between the absorbing flat panel and the heat pipe. The project of a solar collector with a new, absorbing solar rays panel is proposed. To analyze the efficiency of the solar collector based on aluminum structural heat pipes with a new absorption panel, two models of solar collectors were created – with a flat absorber panel and a cylindrical absorber panel.The models of solar collectors based on one aluminum structural heat pipe fixed on aluminum flat and aluminum cylindrical absorption surfaces are investigated by the method of thermophysical experiment.The results of studies of the efficiency of solar collector models are presented. The thermal efficiency of a new solar collector based on an aluminum structural heat pipe with a cylindrical absorbing panel in the initial period of heating water is up to 1 5 % higher than that of a solar collector with a flat absorbing panel, and at the end of heating up to 4 %. The cylindrical surface of the panel plays the role of a concentrator of the reflected part of the radiation and the own radiation of the panel in the region of the heat pipe.Further studies are planned to be conducted in the direction of optimization of the geometric parameters of the heat-absorbing surfaces of solar collectors.

Characterization and application of a selective coating for solar collectors from of the cashew nut shell liquid

Solar energy is the most promising energy source, due to its great availability and applicability in thermal energy applications. However, researchers still experience technological and economical challenge, since many systems that use this energy still have low efficiency and high cost. In this way, the development of new materials and technologies to increase the efficiency of solar thermal collectors is both a challenge and a necessity. In this context, the objective of this work is to obtain and analyze selective surfaces for solar thermal collectors, using cashew nut shell liquid. The cashew nut shell liquid can be classified as technical or natural, depending on the mode of extraction of cashew liquid. An experimental bench was built to simulate a flat plate solar collector under real operating conditions. For comparative purposes, the tests were performed between the cashew nut shell liquid and the commercial surface (MRTiNOX). In order to verify the structure morphology and the chemical composition of the surface, analyzes were performed by scanning electron microscopy. In order to identify the presence of components after the sintering process, the infrared analysis technique was used. To analyze the surface absorbance, the ultraviolet–visible spectroscopy absorbance technique was used. With the tests in real conditions, it was possible to perform the temperature measurements, and later, with the energy balance, the absorptivity, emissivity, and efficiency were calculated. The technical cashew nut shell liquid presented efficiency of 42.86%, while the MRTiNOX, 41.8%. In contrast, natural cashew nut shell liquid obtained efficiency of 31.28%. Thus, the use of technical cashew nut shell liquid, a low-cost regional product, was presented as a viable and satisfactory solution for cost reduction in solar thermal collectors.

Numerical analysis of thermal performance of a solar dryer and validated with experimental and thermo-graphical data

Solar drying is a common method for preservation of food materials and improving thermal efficiency of solar collectors is important as the main part of a solar air heating system. One the most used collectors in solar drying system is flat plate collector and in these collectors the main problem is the low heat flux through the absorber plate, which reduces thermal and drying efficiency of the dryer. In this research, the heat transfer process of the solar dryer was investigated at three conditions non-porous system, with porous system and with porous and recycling system with three methods (experimental, computational fluid dynamics (CFD) and thermo-graphical). The flat plate collector was divided into four equal sections and then the amount of heat transfer coefficient, heat flux and total heat transfer from the collector over the time were calculated for each section. The dryer performance was also evaluated using a heat exchanger that placed at the inlet of the collector. Moreover, the air velocity distribution and temperature counters inside the collector were simulated using computational fluid dynamics method. The results showed that the heat transfer for all cases increased from 10:00 and reached to maximum level at around 12:00–13:00. Due to the reduction of heat accumulation at the end of the collector, heat transfer was more homogeneous for porous collector. Moreover, the results showed that the amount of total heat transfer increased about 16.50% in porous system and 21.19% porous and recycling system compared to non-porous system. The average drying efficiency for solar dryer were about 51%, 53% and 54% for non-porous system, porous system and porous and recycling system, respectively. The results of computational fluid dynamics simulation and thermo-graphical test showed a good agreement between the experimental data and the mentioned methods (R2 > 0.96 and R2 > 0.98).

A review of solar collectors using carbon-based nanofluids

Abstracts The quest to enhance the thermal efficiency of solar collectors by improving the working or absorbing fluid led to the synthesis of nanofluids. Numerous studies have highlighted different nanomaterials such as copper oxide, alumina, silica and so on for dispersion in working fluid and subsequent application in solar collectors. However, carbon nanomaterials have been adjudged as the most promising for preparing nanofluids and heat transfer application. This is because carbon nanomaterials possess remarkable thermophysical properties. These properties contribute a notable enhancement in the thermophysical properties of the working fluid and consequently improve the performance of solar collectors. This study succinctly presents an overview of the performance of various solar collectors utilizing carbon-based nanofluids. The influence of nanofluid concentration, temperature and flow rate on the collector efficiency of the solar collectors were highlighted. This research outcome showed that carbon-based nanofluids with a low concentration of about 0.3 vol% improved the collector efficiency of flat-plate, evacuated-tube, parabolic trough and hybrid photovoltaic thermal solar collector up to 95.12%, 93.43%, 74.7% and 97.3% respectively. Also, direct absorption solar collector using carbon-based nanofluid with a low concentration of at least 0.01 vol% achieved a photothermal efficiency of up to 122.7%. The study further revealed that there is a huge potential to achieve the application of carbon-based nanofluid on a commercial scale. The challenges and prospects for further research were identified.

Experimental study on thermal performance of solar absorber with CuO nano structure selective coating

Abstract To improve the efficiency of solar thermal collector, solar absorber with selective coating is essential. Solar absorbers with CuO nano structure selective coating were prepared by chemical oxidation with 0.065mol/L K2S2O8 and 2.5mol/L KOH solution at 60℃ for 5min, 15min and 60min, respectively, and then heat treated at 180℃ in air for 2h. Transient calorimetric method was applied to obtain the absorptance (α). And outdoor tests were conducted in summer in Nanjing to obtain emittance (e) of CuO nano structure selective coating and instantaneous efficiency of solar absorber. It shows that the oxidation time has obvious effect on absorptance, emittance of CuO nano structure selective coating and instantaneous efficiency of solar absorber. The absorptance and emittance (α/e) are measured to be approximately 0.88/0.13 (5min), 0.90/0.11 (15min) and 0.88/0.39 (60min). The instantaneous efficiency measured to be 76.8% (5min), 78.3% (15min) and 64.9% (60min). CuO nano structure selective coating showed great potential on application of solar thermal collector.

Thermodynamic analysis of a triple-pass solar dryer for drying potato slices

An indirect-type triple-pass forced convection solar dryer has been developed and the performance parameters such as thermal, pickup and exergy efficiency are studied for drying potato slices. The triple-pass solar dryer consists of a blower, triple-pass solar collector integrated with sensible heat storage (sand) bed along with absorber plate and aluminum wire mesh and drying chamber. The experiments were conducted at the optimum value of air mass flow rate of 0.062 kg s−1. The experimental results showed that the maximum collector outlet air temperature of 62 °C was observed at 1.00 pm and the respective solar irradiance of 998 W m−2. The initial moisture content of the potato slices was reduced from 76% (wet basis) to the final moisture content of 13% (wet basis) in 4.5 h. The solar collector thermal efficiency was varied from 12 to 66%, and the mean value of 45% was observed. The pickup efficiency of the solar dryer for drying potato slices was varied from 2.5 to 62.9%, and an average of 29.9% was observed. The exergy efficiency varies from 2.8 to 87.02%, and the mean value for the day was obtained as 53.57%. The thin-layer drying characteristics of potato slices have been studied, and Midilli and Kucuk model was proposed as most suitable drying model.

Enhancement of solar energy collection with magnetic nanofluids

Nowadays, energy crisis has caused widespread concerns about sustainable energy. Solar energy, as sustainable, renewable energy, has attracted many attentions. Compared to other solar energy utilizations, solar collectors are more efficient and commercial devices to collect solar energy. In our present study, well-dispersed magnetic nanofluids (MNFs) are reported that they exhibit excellent optical thermal conversion performance under the suitable magnetic intensity and direction. In this work, the colloidal stability of MNFs was improved by controlling pH within neutral value. One kind of surface modifications, oleic acid, was carried out to enhance the interaction between particles and surfactants. The hydrodynamic diameter was found to be very close to the real size of particle. Meanwhile, a highly efficient solar collection system was built based on controlling the optical thermal performance of MNFs by magnetic fields. The experimental results showed that the thermal efficiency of solar collectors increased with MNFs. The thermal efficiency of MNFs is much higher than base liquid with the concentration of only 0.05 vol.%. Moreover, in the presence of the external magnetic field, the solar collector efficiency increases to the maximum, 25% higher than the conventional parabolic trough and 12% higher than the selective surface absorber. The study indicates that MNFs, even of low-content, have good absorption of solar radiation, and can improve the outlet temperatures and system efficiencies. All these studies show the potential of MNFs in solar thermal conversion applications.

Theoretical and experimental research on effect of fins attachment on operating parameters and thermal efficiency of solar air collector

Flat plate air collector is a type of heat exchanger which absorbs radiated solar energy and exchanges it to heat. According to low efficiency of this type of collectors, a suitable approach is investigated in this paper so as to increase thermal performance of the system. Thermal efficiency of solar collector for two models C1 (without fins) and C2 (with fins) both of 1 m2 surface area with forced convection flow is studied theoretically and experimentally. Rectangular fins are attached over back board in air channel to create turbulence in air flow. In order to measure air temperature, 17 thermal sensors (LM35) are exploited, among which 11 were mounted on absorber plate and the remaining 6 on the back board. Physical design of experimental model are performed in Solidwork and programming of theoretical work in Matlab software. In this research, a fan with constant mass flow rate of 0.033 kg/s is utilized for producing air flow. Results indicate that applying fins in air channel not only reduces Nusselt number from 19.67 to 16.23, but also due to decreasing hydraulic diameter and creating air flow turbulence, causes increase of heat transfer coefficient from absorber plate to air flow and consequently reduction of total heat loss and higher outlet air temperatures. Average difference of outlet air temperature between experimental and theoretical results for both collectors (C1 and C2) was recorded respectively as 7.6% and 9.4%. Thermal efficiency was respectively calculated 30% and 51% for experimental types with and without fins and 33% and 55% for those of theoretical work which generally seem reasonable.

Feasibility Study of a Solar Thermal Cooling Warehouse on a Remote Area: Estimation of the Solar Thermal Collector Area and Efficiency

The objective of this work is to study the feasibility and the design of a thermal solar cooling warehouse on a remote area like Hann fishing quay in Senegal. It will allow us to conserve three tons of fish for a daily operating time of 16 hours. This will allow the fishermen not to throw away their remaining fish at the end of the day or else to sell it at low prices. For the solar resource of the site, we used the meteorological center of the Center of Studies and Research on Renewable Energies (CERER) which is near to the fishing quay of Hann. The required cooling capacity is 8.385 kW. Based on forecast cooling capacity and meteorological data, we have determined the efficiency of solar thermal collectors, the area of the thermal collector field and the solar thermo-mechanical cooling efficiency.