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Background: Acanthamoeba is a resistant protozoan that causes severe diseases, such as GAE and CAK. Because many medications are ineffective on the parasite, the quest to find alternative drugs is in progress. Objective: This research was aim ed to assess the performance of the black and green tea extracts on Acanthamoeba. Methods: The clinical isolate of Acanthamoeba was cultured on non-nutrient agar plates. The black and green tea extracts were prepared via maceration, dried by rotary evaporation, and stored at 4 °C. The main component of the extracts (caffeine) was recognized using GC-MS analysis. The effects of three concentrations of black and green tea extracts were evaluated on the parasite and compared with the control and current drug. Results: Black and green tea extracts have lethal effects on Acanthamoeba cysts and the performance was more than that shown by the control and the current anti-keratitis drug. Moreover, the effectiveness of the tea extracts was tim e- and dose-dependent (P < 0.0001). There was no significant differences between the performance of black and green tea (P > 0.05). Conclusion: Black and green tea extracts demonstrated the potential to inhibit the Acanthamoeba parasite, but the use of tea extract in clinical applications requires further study.

Self-cleaning coating for solar panel has recently gained considerable attention owing to its water and manpower saving feature. Nevertheless, most of the current self-cleaning coatings are either expensive due to the high production cost or not feasible to be utilized in large scales and some of it possesses negative impact on the environment. A simpler and cost-effective approach is required to overcome this problem. One way to overcome this issue is by utilizing Nitrogen to be doped with Titanium dioxide using sol-gel synthesis method. Therefore, this study was conducted to investigate and evaluate the potential of a novel Nitrogen-doped Titanium dioxide/Single-Wall Carbon Nanotubes (N-doped TiO2/SWCNT) photocatalyst nanocomposite for self-cleaning coating application on the surface of solar PV panel surface. The N-doped TiO2 photocatalytic powder was prepared via sol-gel synthesis method and then impregnated with SWCNT by varying the compositions of TiO2 and SWCNT. The nanocomposite was characterized using XRD, FESEM, and FTIR. UV–vis spectroscopy was utilized to evaluate the Methylene blue (MB) degradation in the visible light. This novel coating demonstrated an enhanced photocatalytic activity (PCA) of 72.43% degradation rate and wettability as high as 94.3 ± 2°. The voltage of solar PV panel with and without the self cleaning coating was also measured before and after the dust deposition. The coated solar cells portrayed steady state voltage output which indicates that the coating has no influence on the voltage output. In addition, it offers superior performance in terms of higher voltage after dust deposition testing, confirming the effectiveness of self cleaning coating in maintaining optimum performance of the solar PV. Overall, this study could serve as guidelines in selecting preparing materials (N-doped TiO2/SWCNT) and preparation (sol-gel synthesis) and coating (spin coat) methods of self-cleaning coating for solar panel or other similar application.

The objective of this paper is to investigate the effect of simultaneous using of nanofluid and selective absorber on the improvement of work extraction by a solar flat-plate collector (FPC). Applying a precise model for the exergy factor of solar incident, it is found that the maximum power generation is higher and lower than that by the Petela-Landesberg-Press (PLP) and Carnot model, respectively. Results showed that the influence of temperature ratio ( a ) and geometry factor ( f ) on the exergy efficiency is not such significant when a FPC is working on the Earth's surface. It is also revealed that the key role of the ratio of the absorber plate's emittance to its absorptance must be given attention since only the values lower than 0.174 are allowed by the second law requirements. Furthermore, the exergy efficiency and energy efficiency would experience 10.5% and near 8% enhancement for a 7.5% increase in collector's optical efficiency. Boosting the exergy efficiency by almost 4.1% at 4% volume concentration, demonstrated that nanofluid exploitation instead of plain water would be capable of improving the power generation by the collector.

Solar thermal systems produce steam after being energized by solar parabolic trough concentrators, are incorporated with a steam turbine-generator assembly to produce electricity. This study presents a code for prediction of performance, while under-taking preliminary plant-sizing for a variety of parabolic trough solar fields operating under nominal conditions. The code, named as PTPPPP (Parabolic Trough Power Plant Performance Predictor) consists of four blocks. The code allows prediction of variables including: heat loss coefficient, UL, aperture effective direct normal irradiance, I, heat gain, Qgain, and the thermal efficiency of stand-alone parabolic trough solar thermal power plant in commerce, ηp. The conceptual design of the stand-alone parabolic trough solar involves: selection and sizing of system components, power generation cycles, working fluid types, and power block sizing. The input weather parameters and the operational parameters to the code have been acquired from in-situ measurements. The prediction results of the code have been found in good agreement with literature data with mean error of 0.18% in prediction of output power. In addition, this code is able to provide a flexibility in terms of temperature, heat transfer, and pressure range. Keywords: Direct normal radiation, Direct steam generation, Parabolic trough solar thermal power plant

The uniformity of solar drying process and the quality of the product are inter-related parameters. Drying uniformity is influenced by the significant process air properties which are temperature, humidity and velocity. Accordingly, solar drying uniformity may be improved by integration with dehumidification system and/or optimizing the dryer design. These concepts were reviewed extensively in this paper by brush up the solar thermal hybrid dryers, the performance of solar assisted desiccant systems for dehumidification of drying air, the effect of geometrical parameters on drying performance, and the drying performance of different products. In the context of desiccant systems, the performance of drying is influenced by desiccant material, dehumidifier design and regeneration technique used. While, the issue of solar dryer design is related to drying chamber geometrical parameters, considering multiple drying chambers, and modeling and optimization of dryer design. Coming out with this comprehensive review may motivate to enhance the quality of product and drying performance in terms of cost and time.

One of the crucial factors in improving optical device performance is decreasing reflection, and enhancing light absorption or transmission from wide angles of incidence in a broad wavelength range. In this regard, efficient anti-reflective surfaces demonstrating multifunctional capabilities and showing prospective quasi-omnidirectional anti-reflective and broadband properties are proposed. The selection of a suitable coating material is a key factor in reducing reflection on these surfaces. Hence, this review aims to outline the inception of durable and inexpensive ARC materials that can be applied in different electronic and optical equipment, based on its original conceptualization. Strategies to reduce reflectance will be discussed, and various forms of ARC investigated, paying attention to layer composition and surface topography. To conclude, among all available ARC materials, a 2D rectangular grating for light absorption on GaSb surfaces showed superior properties.

Solar thermal conversion technology harvests the sun’s energy, rather than fossil fuels, to generate low-cost, low/zero-emission energy in the form of heating, cooling or electrical form for residential, commercial, and industrial sectors. The advent of nanofluids and nanocomposites or phase change materials, is a new field of study which is adapted to enhance the efficiency of solar collectors. The concepts of thermal energy storage technologies are investigated and the role of nanomaterials in energy conversion is discussed. This review revealed that although the exploitation of nanomaterials will boost the performance of solar collectors almost in all cases, this would be accompanied by certain challenges such as production cost, instability, agglomeration and erosion. Earlier studies have dealt with the enhancement of thermal conductivity and heat capacity; however, less attention has been given to the facing challenges. Moreover, no exact criteria can be found for the selection of appropriate nanomaterials and their properties for a specific application. In most research studies, the nanoparticles’ material and properties have not been selected based on estimated values so that all the aspects of desired application could be considered simultaneously. The wide spread use of nanomaterials can lead to cost effective solutions as well. Therefore, it seems there should be a sense of techno-economic optimization in exploiting nanomaterials for solar thermal energy storage applications. The optimization should cover the key parameters, particularly nanoparticle type, size, loading and shape which depends on the sort of application and also dispersion technology.

Solar energy in the building can reduce energy consumption in this sector1. This research aims to design a high-rise office building using electricity power generation by photovoltaic panels in the building (BIPV 1 ), which work in a combination of Facades. The objectives for the BIPV design were at the first step to provide at least 20% monthly required lighting electricity for the critical month, which is June and to reduce thermal energy consumption. In this research, the feasibility of the application of the systems was evaluated for the first time with Honeybee plugins in the Rhinoceros software. These plugins are based on the EnergyPlus engine. To achieve the aim with the specified PV3, 830 modules each 2 m2 are required. This BIPV system can provide 51.3% of lighting electricity in February with the maximum electricity production by this system. At the next step, Energy plus weather data (Epw) file is validated with the I.R. Iran meteorological organization (IRIMO) data. The results of the PV system are validated by the experimental data from a PV station in Mashhad (Iran). The produce electricity by this system is 354734.7 kWh/year. The amount of electricity Supplied by BIPV can reduce GHG by the amount of 87 tons of CO2 per year. Reduced thermal energy consumption is validated by ASHRAE 140-2017.

Although there are many studies concerning the estimation of wind potential in different locations of Iran, an adequate evaluation of wind power for onshore locations of this country has not been investigated yet. The purpose of this research is to evaluate the potential of onshore wind in the south of Iran along the Gulf of Oman by comparing three Weibull numerical methods. In the first step, it became clear that the maximum likelihood method (MLM) compared to other methods represented the actual wind data with the lowest error rate and therefore it was selected as an accurate statistical distribution to model the wind speed of the investigated location. Using the MLM, the estimation of wind speed characteristics as well as the techno-economic evaluation of different wind turbines has been investigated. It was concluded that both technically and economically the studied area does not have sufficient wind power for the development of large-scale or grid-connected wind turbines. However, it may hav...

In this research, solar desiccant cooling cycles in ventilation and hybrid mode are simulated. To simulate cycles, at first a model for desiccant wheel simulation is presented and a computer code based on experimental correlations is used to solve equations. Then by TRNSYS software a model for solar hot water system is simulated, and eventually by representing a suitable algorithm, computer program for simulating solar desiccant cooling cycles by EES software is developed. For all components of desiccant cycle, the dynamic optimum were based on regeneration temperature and solar fraction, and after optimum, dynamic cycle performance in an office building with an area of 115 m2 located in Bushehr city, capacity of cooling 3 ton refrigeration were analyzed. The results show that solar desiccant cooling cycles in comparison with compression refrigeration cycles with 40% saving in energy consumption and also during the day and in office buildings have a better performance.

In this paper the wind speed is predicted by the use of data provided from the Mehrabad meteorological station located in Tehran, Iran, Collected between 2003 and 2008. A comprehensive analogy study is presented on Comparison of various Back Propagation neural networks methods in wind velocity forecasting. Four types of activation functions, namely, BFGS quasi-Newton, Bayesian regularized, Levenberg-Marquardt, and conjugate gradient algorithm, werestudied. The data was investigated by correlation coefficient and characterizing the amount of dependency between the wind speed and other input data. The meteorological parameters (pressure, direction, temperature and humidity) were used as input data, while the wind velocity is used as the output of the network.The results demonstrate that for the similar wind dataset, Bayesian Regularized algorithm can accurately predict compared with other method. In addition, choosing the type of activation function is dependent on the amount of input data, which should be acceptably large.

The evaluation of the performance and characteristics of a solar flat-plate collector (FPC) are reported for domestic and industrial requirements in the existing literature. A computer code was developed using matlab to model and evaluate the energetic and exergetic performance of a nanofluid-based FPC for steady-state and laminar conditions. The analysis was performed using practical geometry data, especially the absorber emittance, for a standard collector. Linear pressure losses in manifolds were taken into account, and a more accurate exergy factor corresponding to a correct value of 5770 K for the sun temperature was employed. The results demonstrate that copper–water nanofluid has the potential to augment the internal convection heat transfer coefficient by 76.5%, and to enhance the energetic efficiency of the collector from 70.3% to 72.1% at 4% volume concentration, when compared to the values with water. Additionally, it was revealed that copper nanofluid is capable of increasing the collector fluid's outlet temperature and decreasing the absorber plate's mean temperature by 3 K. The addition of nanoparticles to the water demonstrated a reduction in the total entropy generation by the solar FPC. Furthermore, increasing the nanoparticle size reflected a reduction in the overall performance of the solar collector.

Ethylene glycol and propylene glycol are commonly used as thermal liquids in solar flat-plate collectors (FPCs). They are utilized as base liquid as well as for improving the stability of nanofluids in FPCs. The objective of the present paper is to introduce a renewable-derived bio glycol for use as base liquid in FPCs. The effect of base ratio (BR) of different glycol products on the performance of a conventional FPC and a nanofluidladen FPC is investigated in this paper to determine its suitability. MATLAB programming was employed for modeling the performance of the FPC operating with copper and cerium oxide nanomaterials. The results show that 20:80 bio glycol/water mixture is capable of enhancing the FPC’s energetic efficiency up to 72.1% which is higher than with either ethylene glycol and propylene glycol. The energy efficiency of a glycol-based nanofluid-filled FPC decreases with the base ratio of all three glycol products. Since bio glycol is a non-toxic and safe product, it can be utilized as a safe and environmentally-friend antifreeze and base liquid in nanofluid-filled FPCs.

The near infra-red CuInSeS/ZnS core/shell quantum dots have been investigated toward luminescent solar concentration applications. This quantum dots possess advantages of Stocks shift as large as more than 0.43eV and high photoluminescence quantum yield of 70%. The paper presents the effect of large stock shift CuInSeS/ZnS quantum dots on reducing the reabsorption losses in Luminescent solar concentrators by using experimental investigation. The Luminescent solar concentrators sheet was fabricated in dimension of 40 mm × 30 mm × 3mm by dispersing 0.03 % wt. CuInSeS/ZnS quantum dots particles in a polymethylmethacrylate waveguide and their optical properties (absorptions/emissions) were characterized. Results are showing that the CuInSeS/ZnS quantum dots - Luminescent solar concentrators provides a promising way for the reduction of reabsorption losses in Luminescent solar concentrators.The near infra-red CuInSeS/ZnS core/shell quantum dots have been investigated toward luminescent solar concentration applications. This quantum dots possess advantages of Stocks shift as large as more than 0.43eV and high photoluminescence quantum yield of 70%. The paper presents the effect of large stock shift CuInSeS/ZnS quantum dots on reducing the reabsorption losses in Luminescent solar concentrators by using experimental investigation. The Luminescent solar concentrators sheet was fabricated in dimension of 40 mm × 30 mm × 3mm by dispersing 0.03 % wt. CuInSeS/ZnS quantum dots particles in a polymethylmethacrylate waveguide and their optical properties (absorptions/emissions) were characterized. Results are showing that the CuInSeS/ZnS quantum dots - Luminescent solar concentrators provides a promising way for the reduction of reabsorption losses in Luminescent solar concentrators.

Multi tray solar dryer is commonly used for thin layers drying type due to its ease of manufacturing and economical aspects. However, the drawback of this dryer design is the non-uniformity in the required moisture content of end product. This work presents the development of multi chamber solar drying cabinet using numerical analysis. The main objective is to ensure uniform velocity distribution inside the multi chamber dryer. This aim has been achieved by series of modifications of design concepts based on the aerodynamic behavior of air flow. The results showed that four design phases to come out with optimum design configuration of the multi chamber drying cabinet. The velocity above the splitter has a significant difference of around 0.1 m/s at the end of splitters among the chambers. It is concluded from this result that the cross section flow area has an impact on the uniformity of velocity and a further modification is recommended.Multi tray solar dryer is commonly used for thin layers drying type due to its ease of manufacturing and economical aspects. However, the drawback of this dryer design is the non-uniformity in the required moisture content of end product. This work presents the development of multi chamber solar drying cabinet using numerical analysis. The main objective is to ensure uniform velocity distribution inside the multi chamber dryer. This aim has been achieved by series of modifications of design concepts based on the aerodynamic behavior of air flow. The results showed that four design phases to come out with optimum design configuration of the multi chamber drying cabinet. The velocity above the splitter has a significant difference of around 0.1 m/s at the end of splitters among the chambers. It is concluded from this result that the cross section flow area has an impact on the uniformity of velocity and a further modification is recommended.

The aim of this research is to indicate a steam double effect chiller-heater equipped with solar heat pipe in a certain space with the area of 975 m2 located in Tehran, which is currently equipped with a direct-fired single effect absorption chiller-heater. Thereafter , the most obvious differences of the two chiller-heater systems are compared: the solar cooling system increases coefficient of performance as high as 0.54, decreases CO2 dissemination by 829 tons in each year, and reduces energy consumption by 1552.42 MWh/Yr. Economic analysis of the two systems using break-even-point showed that the use of solar system is attractive in applications that have excess thermal energy, and the conversion of this energy to higher value energy markets is to be more profitable than absorption gas-fired system from 13th year on. Keywords: Technical-economic analysis, energy optimization, solar chiller, absorption chiller-heater, solar heat pipe.

Carbon nanotubes have fascinating chemical and physical properties as indicated by graphite and diamond characteristics, and the reason is their individual atomic structure. They have acquired critical achievements in various fields such as materials, electronic devices, energy storage, separation, and sensors. Recently, antireflective coatings with self-cleaning properties attract critical consideration for their theoretical characteristics and their wide-ranging applications. In this chapter, the benefits of using CNTs as an antireflection and self-cleaning thin coating layer have been discussed to improve mechanical and electrical behavior of solar cells. Transfer-matrix method (TMM) and finite-difference time-domain (FDTD) method were studied as most suitable technique for thin films.

In recent years, energy consumption has become a critical issue in the developed and developing countries. Residential buildings are one of the most users of energy in the construction sector that use the highest share of energy. This paper aims at evaluating the effect of four factors that are temperature, humidity, airflow and pressure on the cooling load in the residential buildings. To achieve this goal, statistical experimental design is used to determine the optimum setting of factors that result in optimum energy usage. Simulation software and energy analysis is used to simulate a two-storey building in Malaysia as the case of study. Final results showed that the temperature, humidity and interaction between them have the most significant effect on the energy cooling load. Moreover, to obtain the minimum value of cooling load the temperature and humidity should be equal to A=20 Celsius degree and B=60% respectively. In addition, the other two insignificant factors, airflow and pressure should be placed at the high level which are equal to C=3 cubic meters per hour, and D=6 Pascal (P) respectively.

Drying fruit, heating residential buildings and providing a hot water supply in villages all consume energy. Using fossil fuel for these purposes creates pollution and costs too much. In contrast, the use of solar energy in these applications leads to a noticeable decrease both in pollution and investment costs. In this study, a new solar system was designed and tested in order to reduce energy usage in rural residential buildings and the food drying industry. As the peaks of energy consumption in the proposed system are not simultaneous, this new system is very effective in reducing energy consumption, controlling energy peaks and reducing environmental pollution. This system has the ability to provide the required energy in both summer and winter modes. In the summer mode, the energy supply is used for providing hot water and drying agricultural products, while in winter mode it is used for rural residences heating and hot water supply. Drying time has been varied between 51.23 and 42.45 h according to type of application, and average temperature difference between room and ambient is almost nearly 10 °C with different air heaters. The system includes energy supply and storage equipment, solar dryers, water collectors and rectangular, triangular, trapezoidal and double-pass with longitudinal fins air heaters. The system was tested in Iran for drying apricots, heating rural residential buildings and supplying hot water for domestic use, meanwhile, the energetic and exergetic efficiency of the system was calculated 37.3–61.3 and 3.2–9.7 respectively for different types of installations.

In this work, a method for increasing the storage capability of a solar thermal energy system has been discussed. The system includes two tanks with the flexibility in choosing the best storage medium on the basis of the solar collector's outlet temperature. The results show that using such a hybrid storage system, the storable energy can be increased. Comparing the results with those for simple common storage systems, the extent of improvement was calculated.For verification of the results, a small pilot system was assembled. The test apparatus operated during 2008-2009 cold months and the parameters were recorded. Comparison of the theoretical and experimental results showed a good agreement.

In this paper, a Simulink® Thermolib Model has been established for simulation performance evaluation of Stand-alone Parabolic Trough Solar Thermal Power Plant in Universiti Teknologi PETRONAS, Malaysia. This paper proposes a design of 1.2 kW parabolic trough power plant. The model is capable to predict temperatures at any system outlet in the plant, as well as the power output produced. The conditions that are taken into account as input to the model are: local solar radiation and ambient temperatures, which have been measured during the year. Other parameters that have been input to the model are the collector's sizes, location in terms of latitude and altitude. Lastly, the results are presented in graphical manner to describe the analysed variations of various outputs of the solar fields obtained, and help to predict the performance of the plant. The developed model allows an initial evaluation of the viability and technical feasibility of any similar solar thermal power plant.

The basic design of luminescent solar concentrator is a transparent plate doped with an appropriate luminescent material (organic dyes, quantum dots), which is able to absorb sunlight (direct and diffuse), and then guides photons produced by photoluminescence to its narrow edges where they are converted by photovoltaic cells. Unfortunately, LSCs have suffered from numerous efficiency losses. Therefore, new luminescent species and novel approaches are needed for its practical application. This paper deals with investigation of nonhazardous, environmental friendly luminescent species include CuInS2/ZnS core/shell QDs. The CuInS2/ZnS QDs possess advantages of Stocks shift as large as more than 130 nm and high photoluminescence quantum yield of 80%. The paper presents the effect of large stock shift CuInS2/ZnS QDs on reducing the reabsorption losses in LSC by using experimental investigation. The LSC sheets were fabricated by dispersing CuInS2/ZnS QDs particles in a polymethylmethacrylate waveguide. A series of LSCs (dimension 4.0 cm × 3.0 cm × 0.3cm) with different CuInS2/ZnS QDs particles concentration (0.015 and 0.03 wt.%) were fabricated and their optical properties (absorptions/emissions) were characterized. The results show that the CuInS2/ZnS QDs-LSC provides a promising way for the reduction of reabsorption losses in LSCs.

The goal of this paper is to optimize the productivity of manufacturing system by integrating computer simulation, design of experiments (DOE) and particle swarm optimization (PSO) algorithm. Optimizing productivity of colour factory was considered as the case of this study. To evaluate and estimate the effect of main factors, 2n factorial design with higher and upper levels and centre points was considered. After obtaining the significant factors, the local optimum setting of the significant factors was determined using the steepest ascent method and response surface methodology (RSM) approach. Finally, the global optimum productivity was achieved by computer programing of PSO method. Base on the final result, maximum productivity occurs in the point of 87.23 that is relevant to number of labour (B) = 26 and failure time of lifter (C) = 78.04 min. In addition, other two factors A (Service rate of Delpak mixer) and D (Number of permil) should be located at low level to obtain maximum productivity.

The present study deals with the economic and environmental assessment of energy conservation in residential buildings. In this approach, the heating and cooling loads of a typical residential building in Tehran with micro gas turbine units have been considered. This 8000 m2 area building possesses 10 floors with 4 units per floor. Five distinguished scenarios, wall insulation, roof insulation, shading, triple glazing and all of the four energy conversation methods have been proposed concerning the decrease in the energy usage. Each of the energy conservation methods was studied separately in four former scenarios and all of these methods were investigated simultaneously in the fifth latter scenario. To achieve the heating, cooling and electrical loads, a number of 30 kW combined heat and power (CHP) micro gas turbine units have been taken into consideration without energy conversation methods. The results show that the best scenario concerning the minimum value of energy loss is that for which the mean heating and cooling loads were 514.58 and 519.08 kW, respectively. Also the number of CHP micro gas turbine units reduces from 30 to 11 and also the total electricity cost decrease from 0.32 to 0.16 US$/kWh with consideration social cost of air pollution.

With the fact that Malaysia is one of the fast- growing countries, demand of energy increment is rapid. Malaysia is able to obtain ample amount of annual solar radiation due to its location at equator. If this is utilized proficiently and effectively, then, it can suffice the domestic needs as well as the industrial needs in terms of energy consumption. This article proposes a parabolic Trough Power Plant which is designed with 1.2 kW net electric output. Consequently, the results of theoretical calculations are detailed in the article, while, ensuring the analysing of design proposed through the MATLAB software. The results showed that by making use of aperture having an area of approximately 80 m2, maximum useful heat gain of 20701W at 13:00 pm was attained in March. The maximum net power is 11.84 kWh/day in February.

This paper proposes the design of a solar water bath heater for Central Power Plant in Assaluyeh region in south of Iran with the latitude of 27 °N. This heater uses flat plate solar collectors in an open circuit system. Solar intensity, absorbed radiation and ambient temperature are the regional parameters which are known to the designer. The temperature of the bath of water which is the outlet collector temperature (70 °C) belongs to the known parameters in the mentioned station. Flow rate, heat loss factor, the inlet temperature of the collector and the area which is the most important factor to evaluate the economical issues of the system are calculated with modeling the water bath with a shell and tube heat exchanger. The solar water bath heater is then simulated with TRNSYS software. The obtained results are in good agreement with analytical solution based on Duffie and Beckman method.Copyright © 2010 by ASME

This study compared the impacts of using copper nanofliud to enhance the efficiency of flat solar collectors with closed loop and under forced convection heat transfer circumstances to traditional work fluids. Various concentrations of nanoparticles in water and water/glycol, from 250ppm to 3000ppm, were examined for volume fraction impact. Results indicate that the laboratory tests were different from those under real conditions because of the high concentration of nanoparticles used in laboratory tests; however, by using nanofluid (even with low concentrations around 0.3%) solar collector efficiency improved (3.2%).Results have also shown that the use of copper nanofluid in ethylene glycol as the base fluid causes a significant reduction in collector efficiency, due to the increase in viscosity. However, using higher flow rates caused the heat transfer rate to rise because of increased turbulence.

In this paper solar energy potential has been estimated by two methods which are clearness index and artificial network (ANN) methods. The selected region is Seri Iskandar, Perak (4°24´latitude, 100°58´E longitude, 24 m altitude). Experimental data (monthly average daily radiation on horizontal surface) was obtained from UTP solar research site in UTP campus. The data include the period of 2010 to 2012 and were used for testing the artificial neural network model and also for determination of clearness index. Also the experimental data of the three meteorological, Ipoh, Bayan Lepas & KLIA were used in calculating the clearness index and for training the neural network. Result shows that clearness index for Seri Iskandar is 0.52, the highest radiation is on February (20.45 MJ/m 2 /day), annual average is 18.25 MJ/m 2 /day and clearness index is more accurate than ANN when there is limited data supply. In general, Perak states show strong potential for solar energy application.