collector

Open Access Article

1 - The Calculation of Optimized Slop of Flat Solar Collectors and Comparing of Their Application at Each Month of the Year in Kerman
ahmad jamee Hasan Zolfagharzadeh Pooria Akbarzadeh

10.30495/jest.2020.11198

Background and Objective: Today energy crisis and inherent environmental pollution caused by increasing consumption of non-renewable resources are one of the most major concerns of many countries including Iran and using of them is one of the most important factors to E More

Background and Objective: Today energy crisis and inherent environmental pollution caused by increasing consumption of non-renewable resources are one of the most major concerns of many countries including Iran and using of them is one of the most important factors to Earth demolition and climatic changes. Thus, numerous developed and enlarged countries try to extend the application and use of renewable energy resources. In this regard, the solar energy is one of the most important renewable and sustainable energy sources in the world and it mainly can be enumerated as the second largest energy sources in Iran after wind energy. This energy can be exploited in several methods such as flat collectors as one of the simplest and most usable systems that can be used in the buildings and solar chimney power plant. Due to daily and seasonal variations of the sun radiation, the optimal tilt estimation of collectors with maximum efficiency is very important.Method: This paper is based on a mathematical pattern and climatic data and the optimized tilt of flat collectors in city of Kerman is investigated. Then, by comparing and analyzing results of charts and tables, optimized tilt of flat collector at each month, season and annual are extracted and contrasted. Additionally, the percent of received radiation of each angle of plates in comparison to the optimized Angele are discussed.Findings: In the conclusion section, the optimal angle tilt of collector over the year including spring, summer, autumn and winter seasons besides the optimal angle building heating systems and outdoor swimming pools heating systems are also presented. Finally, efficiency of vertical and horizontal collectors has been investigated with respect to maximizing the efficiency of optimal tilt of collector over the year. Manuscript profile

Open Access Article

2 - Effect of Leakage Modification and Cooling Flow Rate Increase of Water-Cooled Condenser on NVD System Performance Equipped with Vacuum Tube Collectors
Mohammad Javad Abbaspour mohammad behshad Shafiei

10.22034/jest.2020.42685.4577

Background and Objective: Lack of access to sufficient fresh water is a major threat to people around the world, and to prevent this, extensive research is being done to find new ways to purify different sources of brackish water at lower cost, energy and environmental More

Background and Objective: Lack of access to sufficient fresh water is a major threat to people around the world, and to prevent this, extensive research is being done to find new ways to purify different sources of brackish water at lower cost, energy and environmental impacts. The purpose of this study is to produce the freshwater through an NVD system using vacuum tube collectors and vacuum creation by a vacuum pump. Hence, this kind of system could be considered as an innovative combination one; in addition, the effect of different vacuum pressures on yield, then the effect of leakage modification and flow rate increase of cooling water on the system performance were experimentally investigated. Method: In this research, a vacuum pump was utilized to create an initial vacuum, and when it is switched off, a barometric water column maintains the vacuum naturally throughout the consecutive days. The vacuum collectors were used in order to enhance the saline water heat transfer; later the system performance was continually examined. After the improvements were carried to the system, the yield and efficiency were analyzed and compared with the first test. Furthermore, a pressure gauge, a pyranometer and some thermocouples were applied so as to measure the system pressure, solar radiation and temperatures respectively. Findings: The current study found that the yield and efficiency of the system increased by raising the vacuum pressure; besides, after the leakage modification and cooling water flow rate enhancement, the efficiency has been insignificantly varied in the first consecutive days resulting in a superior capability to produce fresh water for more than three days without reusing the vacuum pump. Discussion and Conclusion: The results of this study indicated that raising the vacuum pressure increased the yield and efficiency so that they reached to 8.114 kg/m2d and more than 51% respectively. Moreover, the efficiency slightly varied and as a result, the system would be able to produce freshwater for more than three days without reutilizing vacuum pump. Manuscript profile

Open Access Article

3 - Solar combi-systems: a new solution for heating buildings
Morteza Khalaji Asadi Zahra Abedi Nima Sharee

Solar combi-systems have attracted more attention technologically and economically compared with the other thermal applications of the solar energy in the world. The reason why these systems are preferred for the provision of hot water and solar heating is that they nee More

Solar combi-systems have attracted more attention technologically and economically compared with the other thermal applications of the solar energy in the world. The reason why these systems are preferred for the provision of hot water and solar heating is that they need a medium temperature which can be supplied by flat-plate collectors and at a lower cost than that of other types of collectors. In this paper, first the thermal loads of residential apartments (in two cases: with common materials and with materials dictated by the national rules of construction) in Hamedan and Karaj have been computed. Then, suitable solar combi-systems have been designed for each apartment. Subsequently, the rate of thermal energy that can be provided by this system and windows has been calculated. In the next step, considering the heating energy needed by building and studying the expense-efficiency curve of the solar combi-system, the number of solar flat-plate collectors has been calculated, and considering the effect of solar panels shadow and the space limitation of the roof, a hybrid (fossil-solar) system has been proposed. The results show that the average solar energy which can be used varies from 15 1o 45 percents in the cold months of the year. Consequently, considering the annual fuel savings and also the reduction of social costs in cold regions using the solar combi-system as well as the international price of energy, about 43 million Rials will be saved in fuel costs so that the initial high investment expenses will be returned in less than two years. In the same way, about 10 million Rials will be saved in fuel costs in temperate regions; therefore, the initial investment expenses will be returned in four years Manuscript profile

Open Access Article

4 - Numerical study on nanofluid natural convection in a vacuum tube solar collector with phase change materials
seyed Alireza Nazem Iman Zahmatkesh

As an eternal and widespread energy source, solar energy has a low density while its intensity is changing continuously. Unavailability of the solar energy in nights and the gap between the time of radiation and its consumption are concerned as the main drawbacks of thi More

As an eternal and widespread energy source, solar energy has a low density while its intensity is changing continuously. Unavailability of the solar energy in nights and the gap between the time of radiation and its consumption are concerned as the main drawbacks of this type of energy. In applications such as domestic hot water (DHW), phase change materials (PCMs) can successfully remove this shortcoming due to their high thermal capacity and constant temperature during the phase change process. However, thermal conductivity of water is relatively low which reduces the performance of vacuum tube solar collectors. This properties can be improved substantially with the utilization of nanofluids. This paper presents a numerical study on nanofluid natural convection in a vacuum tube solar collector with phase change materials. The studied nanoparticles include copper oxide, titanium oxide, iron oxide, aluminum oxide, and graphene oxide. The obtained results show that for all of the current nanoparticles, rise in the nanoparticles volume fraction is accompanied by a decrease in the exit temperature of the collector. It is found that the highest temperature belongs to the graphene oxide nanoparticles. Manuscript profile

Open Access Article

5 - Evaluation of heat transfer performance of two-phase nanofluid flow in a parabolic solar collector with eccentric absorber and solid insulation
mojtaba jamiati Hossein Pourmohamadian

In this study, the flow field analysis and heat transfer of two-phase nanofluid flow in a parabolic solar collector with eccentric absorber and solid insulation have been investigated. The fluid used in this collector is nanofluid of water - Aluminium. The main aim of c More

In this study, the flow field analysis and heat transfer of two-phase nanofluid flow in a parabolic solar collector with eccentric absorber and solid insulation have been investigated. The fluid used in this collector is nanofluid of water - Aluminium. The main aim of current study is to investigate the effect of using eccentric absorber system and solid insulation on the energy efficiency of linear parabolic collectors. For this purpose, energy efficiency has been measured and presented for different states (including ambient temperature, fluid inlet temperature, nanofluid volume fraction, nanoparticle diameter and geometric characteristics). The study is in turbulent flow regime and in order to model it, the k epsilon turbulence model has been used. In order to solve the survival equations, the finite volume method and the SIMPLE C algorithm have been used. Different optimal models are introduced in terms of having the highest energy efficiency, and the best model is determined. Based on obtained results, the highest energy efficiency in different Reynolds is related to the novel collector and two-phase model(TPM). In the next positions, respectively, are the novel collector and single-phase model(SPM), the basic collector and two-phase model, and at the end, the basic collector and single-phase model. It was also found that as the Reynolds number increases, all modes have an uptrend. The maximum amount of energy efficiency was for the novel collector and the two-phase model at Reynolds 15000, Which is equal to 68%. Also, the maximum energy efficiency for eccentricity 20 mm at Reynolds 15000, which is equal to 74.9%. Manuscript profile

Open Access Article

6 - Investigation of the application of nanotechnology to increase the direct absorption of solar radiation
mojtaba jamiati

The purpose of this study is to evaluate the potential of solar nanofluids (liquid with dispersed nanoparticles) for direct absorption of solar radiation and steam production. At present, solar thermal energy systems suffer great losses due to heat transfer processes, t More

The purpose of this study is to evaluate the potential of solar nanofluids (liquid with dispersed nanoparticles) for direct absorption of solar radiation and steam production. At present, solar thermal energy systems suffer great losses due to heat transfer processes, therefore, the development of nanotechnology and its achievements such as various nanoparticles, has created high hopes to increase the efficiency of solar collectors through direct absorption of sunlight. In order to make optimal use of solar nanofluid systems, it is necessary to identify and study them. In this research, four different nanofluids have been synthesized, identified and evaluated. Two of them were water-based nanofluids and the other two were thermal oil-based nanofluids. Also, the optical properties of nanofluids were measured at room temperature with a spectrophotometer and compared with the base fluid. The optical properties, in addition to being measured at room temperature, have also been evaluated after heat treatment on nanofluids at high temperatures. This temperature increase is intended to recreate operating conditions for those closer to the actual applications. DLS measurements show a similar hydrodynamic average of 138 nm for the sample containing SDS and 135 nm for the sample containing SDS and PVP. Manuscript profile

Open Access Article

7 - perimental Study on the Performance of a New Type Solar Air Heater with Cross-Corrugated Surface on Different Environmental Conditions
نادر رهبر محمد جوادی نیا ایزدی پژمان ظهوریان ایزدی

In This paper, the effect of using cross-corrugated surface as an absorber plate in a solar air collector was experimentally investigated. Black plate geometries of air heater was V-type, while some vertical baffles were used to conduct air flow between surfaces. With t More

In This paper, the effect of using cross-corrugated surface as an absorber plate in a solar air collector was experimentally investigated. Black plate geometries of air heater was V-type, while some vertical baffles were used to conduct air flow between surfaces. With these modification turbulence regime and heat transfer enhancement were achieved. A centrifugal fan was also used to produce 0.003-0.01 kg/s air flow. Moreover different position angles (30, 45 and 90 degrees) were used to evaluate the performance of the system. The results showed that with these modification the Nusselt number was 5 times greater than before. Furthermore, a new correlation was proposed which has a good accuracy in estimation of Nu number. Manuscript profile

Open Access Article

8 - Development of solar air collectors for drying applications
Mohammad Mehdi Ebn Ali Ali Heydary

In this study, three types of solar air collectors (flat plate, finned, and v-corrugated) have been experimentally investigated in order to achieve an effective design which can be appropriate for a solar dryer. The experiments have been performed according to the ASHRA More

In this study, three types of solar air collectors (flat plate, finned, and v-corrugated) have been experimentally investigated in order to achieve an effective design which can be appropriate for a solar dryer. The experiments have been performed according to the ASHRAE standard and under real climatic conditions of Semnan (35° 33′ N, 53° 23′ E), Iran. Over a broad range of operating and design conditions, the performance of all three collectors have been studied. Based on the results, v-corrugated collector and flat plate one found to be the most and least efficient, respectively. Moreover, the collectors have also been studied in double pass mode in order to examined the extent in efficiency improvement. Manuscript profile

Open Access Article

9 - An Experimental Investigation on performance of MWCNT-water nanofluid in a flat plate solar water heater under natural and forced circulations
kourosh hasanzade Amid Khosrowdad

Nowadays, in order to heating water in low-temperature residential applications, flat plate solar water heater is widely used. In this paper, we aim to discuss the thermal performance of MWCNT-water nanofluid in a flat plate solar water heater. The nanofluid has been pr More

Nowadays, in order to heating water in low-temperature residential applications, flat plate solar water heater is widely used. In this paper, we aim to discuss the thermal performance of MWCNT-water nanofluid in a flat plate solar water heater. The nanofluid has been prepared in solid volume fraction of 0.05% and its thermal performance has been experimentally investigated. In order to make a dispersed and stable nanofluid, Sodium Dodecyl Benzene Sulfonate surfactant has been used. The results showed that using the nanofluid has a considerable effect on improvement of the performance of the flat plate solar water heater. Furthermore, the increase of the system’s performance under natural circulation is much higher than that of forced circulation. Manuscript profile

Open Access Article

10 - Effects of rotational flow on energy efficiency of a novel parabolic through solar collector equipped with elliptical ribbed absorber tube filled with non-Newtonian two-phase nanofluid
mojtaba jamiati

The main purpose of this study is to investigate the effect of using an elliptical absorber system with helical ribbed tube on the energy efficiency of linear parabolic collectors. For this purpose, energy efficiency has been measured and presented for different modes, More

The main purpose of this study is to investigate the effect of using an elliptical absorber system with helical ribbed tube on the energy efficiency of linear parabolic collectors. For this purpose, energy efficiency has been measured and presented for different modes, and finally different optimal models are introduced in terms of having the highest energy efficiency, and finally the best model is determined. Based on the obtained results, the highest energy efficiency in different Reynolds is related to the new collector and single-phase model. According to the results of this dissertation, the use of grooved pipe has an effect on increasing the efficiency of the collector. As the number of grooves increases from 1 to 3, the collector efficiency increases. It was also found that the collector efficiency increases with increasing step and slope amplitude. by increasing the groove angle from 10 ° to 50 °, the collector efficiency increases and the maximum value of η is obtained at ° ξ = 60. However, by increasing the groove angle from 50 ° to 60 °, the collector efficiency decreases. Manuscript profile

Open Access Article

11 - The effects of using two compound twisted tapes to enhance the performance of a parabolic trough solar collector
mojtaba jamiati Hossein Pourmohamadian

In this study, the effect of spinning tape on the thermal hydraulic performance of water-hybrid water-hybrid carbon nanotubes-aluminum oxide inside a linear parabolic solar collector has been investigated numerically. The study is in turbulent flow regime and in order t More

In this study, the effect of spinning tape on the thermal hydraulic performance of water-hybrid water-hybrid carbon nanotubes-aluminum oxide inside a linear parabolic solar collector has been investigated numerically. The study is in turbulent flow regime and in order to model it, the k epsilon turbulence model has been used. In order to solve the survival equations, the finite volume method and the SIMPLE C algorithm have been used. The study was performed to investigate the hydraulic and thermal performance of the parabolic solar collector equipped with 1, 2 and 3 twisted strips. Also, the results obtained from the simulation of a linear parabolic solar collector with a radiant strip are compared with when the solar collector is simple (without a radiant strip). Different concentrations of nanoparticles (1 to 3% by volume) were used for Reynolds numbers from 3000 to 18000. The obtained results are presented in the form of Nusselt dimensionless number diagrams, pressure drop and thermal hydraulic performance evaluation criteria(PEC). Manuscript profile

Open Access Article

12 - Thermal and hydraulic analysis of a novel p double fluid parabolic through solar collector equipped with corrugated tube and insulator roof
mojtaba jamiati

The present study investigates a double-fluid volumetric based parabolic trough solar receiver. The control volume approach is used to solve the system of classical single phase governing equations by using the finite volume method. The standard k–ε turbul More

The present study investigates a double-fluid volumetric based parabolic trough solar receiver. The control volume approach is used to solve the system of classical single phase governing equations by using the finite volume method. The standard k–ε turbulence model with enhanced wall function is selected. According to obtained results, the value of efficiency of Conventional-Parabolic-Through-Solar-Collectors (CPTSCs) and Novel-Parabolic-Through-Solar-Collectors (NPTSCs) reduces by increasing of inlet temperature of base fluid and therefore, there is an optimum inlet temperature for all configurations and it is equal to 40°C. Manuscript profile

Open Access Article

13 - Thermoeconomic Analysis of a Steam Rankine Cycle ‎Integrated with Parabolic Trough Solar Collectors
Seyyed Masoud Seyyedi

Manuscript profile

Open Access Article

14 - An Efficient Routing Algorithm to Lifetime Expansion in Wireless Sensor Networks
Meisam Kamarei Ghasem Kamarei Zohreh Shahsavari

Manuscript profile

Open Access Article

15 - Application of nanofluids for heat transfer enhancement in solar water heaters
محمد رضا جعفری نصر سیده فاطمه حسینی

In this study, techniques for heat transfer enhancement reviewed. Application of nanofluids was studied as a new technique for more energy saving and heat recovery. Transys version17 simulation was used for prediction of thermal efficiency of water and various nanofluid More

In this study, techniques for heat transfer enhancement reviewed. Application of nanofluids was studied as a new technique for more energy saving and heat recovery. Transys version17 simulation was used for prediction of thermal efficiency of water and various nanofluids in a flat plate solar collector. Nano fluids that were used in this simulation analysis are copper oxide, copper, and alumina. The results show that the heat transfer and thermal efficiency of copper nanofluid are greater than other working fluids while the exergy efficiency of alumina is greater. Gambit 2.4.6 was used for our CFD calculation along with the Fluent version17.2. We used a model to numerically simulate the heat transfer. The governing equations and corresponding boundary conditions are converted to dimensionless forms and solved numerically by the finite element method. The results show that efficiency of copper is 67% and it is greater than alumina and copper oxide efficiency. Manuscript profile

Open Access Article

16 - افزایش راندمان خروجی کل مدول فتوولتائیک با بکارگیری کلکتور فتوولتائیک - حرارتی
سید امیر به مونسی

  تابش خورشیدی دمای سطح مدول فتوولتائیک (PV) را افزایش می‌دهد که این افزایش دما، سبب کاهش راندمان الکتریکی و عمر مفید سلول‌های فتوولتائیک می‌شود. یکی از روش‌های کاهش دمای مدول‌های فتوولتائیک، کاهش حرارت سطح مدول به‌واسطه گردش سیالی همچون آب یا هوا است. به دستگاه More

  تابش خورشیدی دمای سطح مدول فتوولتائیک (PV) را افزایش می‌دهد که این افزایش دما، سبب کاهش راندمان الکتریکی و عمر مفید سلول‌های فتوولتائیک می‌شود. یکی از روش‌های کاهش دمای مدول‌های فتوولتائیک، کاهش حرارت سطح مدول به‌واسطه گردش سیالی همچون آب یا هوا است. به دستگاه‌هایی که بر این مبنا عمل می‌کنند کلکتورهای ترکیبی فتوولتائیک – حرارتی (PV/T) می‌گویند. معمولا کلکتورهای ترکیبی فتوولتائیک - حرارتی، از یکپارچه‌سازی مدول فتوولتائیک و کلکتور حرارتی به منظور جلوگیری از تماس مستقیم سیال خنک کننده با سطح مدول ساخته می‌شود. جاذب حرارتی به دلیل دفع حرارت از سطح مدول به سیال بسیار حائز اهمیت است بنابراین عملکرد حرارتی و الکتریکی یک کلکتور PV/T به طراحی مناسب جاذب وابسته است. در این تحقیق، ابتدا طبقه‌بندی و ساختارهای مختلفی از کلکتور PV/T بررسی شدند. در ادامه راندمان حرارتی و الکتریکی 9 طرح کاربردی از کلکتور PV/T به صورت تئوری با یکدیگر مقایسه شدند. سپس راندمان الکتریکی کلکتور PV/T نوع ورق و لوله توسط مدول PV شاهد تحت آزمون قرار گرفت. بر طبق نتایج حاصل از این پژوهش، در صورتی که دمای سیال ورودی پایین باشد، کلکتور PV/T راندمان کل بالاتری در مقایسه با کلکتور حرارتی یا مدول PV مجزا خواهد داشت. Manuscript profile

Open Access Article

17 - Creating Sustainable Income through the Cashew Nuts Value Chain (Evidence from Ghana)
Nicholas Oppong Mensah Richmond Anaman Kingsford Nyarko- Fordjour Samuel Afotey Anang Anthony Donkor Jacqueline Twintoh

10.22034/jon.2021.1931764.1115

Manuscript profile

Open Access Article

18 - ساخت کالکتور خورشیدی متمرکز کننده سهموی خطی و پیش بینی عملکرد آن
محمود تاجی

هدف از انجام این تحقیق ساخت و پیش بینی عملکرد کالکتور خورشیدی متمرکزکننده است که طرح کلی آن همانند طرحهای رایج این نوع کالکتور بوده، ولی سطح منعکس کننده بجای آینه از ورق نازک فولاد آینه ای است. برای ساخت ابتدا سازه اصلی نگهدارنده با اتصال موازی سازه های پیش ساخته ⩝ شکل More

هدف از انجام این تحقیق ساخت و پیش بینی عملکرد کالکتور خورشیدی متمرکزکننده است که طرح کلی آن همانند طرحهای رایج این نوع کالکتور بوده، ولی سطح منعکس کننده بجای آینه از ورق نازک فولاد آینه ای است. برای ساخت ابتدا سازه اصلی نگهدارنده با اتصال موازی سازه های پیش ساخته ⩝ شکل صفحه ای ساخته شد و یک کمان سهمی شکل تفلنی بعنوان تکیه گاه سطح منعکس کننده در دهانه هر سازه نصب گردید. سپس ورق فولادی در دهانه سازه اصلی به شکل سهمیگون مونتاژ شد. بقیه قسمتها مشابه روشهای مرسوم ساخته و مونتاژگردید.برای پیش بینی عملکرد، پس از تعیین رابطه راندمان بصورت تابعی از زاویه اصابت تابش خورشید برمبنای تئوریهای این نوع کالکتور، راندمان و نرخ خالص جذب گرما به کمک نرم افزار متلب وبرنامه نویسی در محیط ان محاسبه و برحسب زمان ظاهری خورشید در چند روز سال رسم گردید. نتایج نشان داد اگر تابش خورشید به امتداد عمود برافق نزدیک باشد، راندمان از50% در صبح تا 60% درظهر افزایش یافته و بعدازظهرتا عصر به 50% کاهش میابد. در غیراینصورت راندمان از 60% در صبح به50% درظهر کاهش یافته و مجددا" تا 60% در عصر افزایش میابد. نرخ خالص جذب گرما (w/m2) هر دو حالت در ظهر حداکثر(450-550 ) و در صبح و عصر حداقل (400-450) بود.گرچه راندمان کالکتور ساخته شده با راندمان کالکتورهای معمول تفاوت چندانی ندارد، اما زمان و هزینه کمتر برای مونتاژ آن و کیفیت بالاتر شکل هندسی و دوام بیشتر سطح منکس کننده درمقایسه با کالکتورهای معمول قابل ملاحظه است. Manuscript profile

Open Access Article

19 - Computational fluid dynamics analysis and geometric optimization of solar chimney power plants by using of genetic algorithm
Amir Karami Davood Toghraie

In this paper, a multi-objective optimization method is implemented by using of genetic algorithm techniques in order to determine optimum configuration of solar chimney power plant. The objective function which is simultaneously considered in the analysis is output pow More

In this paper, a multi-objective optimization method is implemented by using of genetic algorithm techniques in order to determine optimum configuration of solar chimney power plant. The objective function which is simultaneously considered in the analysis is output power of the plant. Output power of the system is maximized. Design parameters of the considered plant include collector radius (Rc), collector height (Hc), chimney height (Ht), chimney radius (Rt) and heat flux ( ). The multi-objective optimization results show that there are a strong positive correlation between the chimney height and the output power, as well as a negative correlation between the solar collector radius and the output power. Also, it was concluded that, output power of the plant could be considerably increased with increasing solar chimney height while increasing collector radius could slightly reduce output power This study may be useful for the preliminary estimation of power plant performance and the power-regulating strategy option for solar chimney turbines. Manuscript profile

List of Articles collector

Sanad

Links

Related Centers

Technical Support

Official pages