Corrigendum to “Experimental analysis of a heat pipe operated solar collector using water–ethanol solution as the working fluid” [Solar Energy 118 (2015) 267–275]

The integrated usage of solar energy systems, heat pump applications, and thermal energy storage units is an effective way for heating systems due to their sustainability and stability in operations. In this study, a novel direct solar-assisted heat pump with thermal energy system has been designed which uses the solar collector as the evaporator of the heat pump. Besides, two-dimensional transient numeric analyses have been conducted for the thermal energy storage unit using the ANSYS Fluent 16.2 commercial software package. With this direct system, the heat required for heating systems is supplied from the condenser with the heat received from the solar collector of the working fluid. For an effective and high performance system, the solar collector is designed as a double-pass which provided superheating of the working fluid. It is aimed to store the surplus energy from the solar energy in the thermal energy storage unit and to operate the system continuously and efficiently in both sunny and overcast weather conditions. Furthermore, the system has been analyzed theoretically and the results show that coefficient of performance may improve. As a result, this newly designed system can be successfully applied for thermal applications.

Download Full-text

Numerical simulation of concentrating solar collector P2CC with a small concentrating ratio

Thermal Science ◽

10.2298/tsci120430184s ◽

2012 ◽

Vol 16 (suppl. 2) ◽

pp. 471-482 ◽

Cited By ~ 2

Author(s):

Velimir Stefanovic ◽

Sasa Pavlovic ◽

Marko Ilic ◽

Nenad Apostolovic ◽

Dragan Kustrimovic

Keyword(s):

Mathematical Model ◽

Fluid Flow ◽

Solar Radiation ◽

Solar Energy ◽

Radiation Intensity ◽

Solar Collector ◽

Numerical Procedure ◽

Working Fluid ◽

Flow Rates ◽

Solar Radiation Intensity

Solar energy may be practically utilized directly through transformation into heat, electrical or chemical energy. A physical and mathematical model is presented, as well as a numerical procedure for predicting thermal performances of the P2CC solar concentrator. The demonstrated prototype has the reception angle of 110? at concentration ratio CR = 1.38, with the significant reception of diffuse radiation. The solar collector P2CC is designed for the area of middle temperature conversion of solar radiation into heat. The working fluid is water with laminar flow through a copper pipe surrounded by an evacuated glass layer. Based on the physical model, a mathematical model is introduced, which consists of energy balance equations for four collector components. In this paper, water temperatures in flow directions are numerically predicted, as well as temperatures of relevant P2CC collector components for various values of input temperatures and mass flow rates of the working fluid, and also for various values of direct sunlight radiation and for different collector lengths. The device which is used to transform solar energy to heat is referred to as solar collector. This paper gives numerical estimated changes of temperature in the direction of fluid flow for different flow rates, different solar radiation intensity and different inlet fluid temperatures. The increase in fluid flow reduces output temperature, while the increase in solar radiation intensity and inlet water temperature increases output temperature of water. Furthermore, the dependence on fluid output temperature is determined, along with the current efficiency by the number of nodes in the numerical calculation.

Download Full-text

Study on Heat Transfer Characteristics of Loop Heat Pipe for Solar Collector

Volume 7: Fluids and Heat Transfer, Parts A, B, C, and D ◽

10.1115/imece2012-86260 ◽

2012 ◽

Author(s):

Shota Sato ◽

Shigeki Hirasawa ◽

Tsuyoshi Kawanami ◽

Katsuaki Shirai

Keyword(s):

Heat Transfer ◽

Heat Pipe ◽

Heat Transfer Rate ◽

Solar Collector ◽

Transfer Rate ◽

Thermal Conductance ◽

Filling Ratio ◽

Working Fluid ◽

Loop Heat Pipe ◽

Single Tube

We experimentally study the thermal conductance of single-tube and loop heat pipes for a solar collector. The evaporator of the heat pipe is 1 m long, 6 mm in diameter and has 30° inclination. The thermal conductance is defined as the heat transfer rate divided by the temperature difference between the evaporator-wall and the condenser-wall. Effects of heat transfer rate, saturation temperature of the working fluid, liquid filling ratio, inclination angle, and position of the evaporator on the thermal conductance are examined. We found that the thermal conductance of the 30°-inclined loop heat pipe with an upper-evaporator is 40–50 (W/K), which is 1.8 times higher than that of the vertical loop type and 3 times higher than that of the single-tube type. Thus, the inclined loop heat pipe is preferable for a solar collector. There is an optimum liquid filling ratio. When the liquid filling ratio is too small, a dry-out portion appears in the evaporator. When the liquid filling ratio is too large, the liquid flows in the condenser to decrease heat transfer area. Also we numerically analyze the thermal conductance of a vertical loop heat pipe.

Download Full-text

Investigation of Performance of Solar Flat and Curved Plate Collectors through Numerical Simulations

Mehran University Research Journal of Engineering and Technology ◽

10.22581/muet1982.2101.06 ◽

2021 ◽

Vol 40 (1) ◽

pp. 66-74

Author(s):

Luqman Ahmed Pirzada ◽

Xiaoli Wu . ◽

Qaiser Ali ◽

Asif Khateeb .

Keyword(s):

Solar Energy ◽

Flat Plate ◽

Solar Collector ◽

Numerical Study ◽

Hot Water ◽

Working Fluid ◽

Solar Panels ◽

Modeling Tools ◽

Design Work ◽

Flat Plate Collector

Solar energy is radiant light as a form of thermal heat energy which can be obtained and used by means of a variety of solar apparatus. As apparatus the flat and curved plate solar collector is specifically designed for assembling solar energy as a solar water heater system. The designing potency of this collector lone can generate medium level hot water from radiant sunlight source via absorbed plates. Standard type flat and curved plates solar collector plates are mostly used in remote coldest regions of the world where hot water is consumed for commercial and domestic purposes. These types of solar collector Plates can cheaply be manufactured compared to other solar panels like solar Shingles, Polycrystalline Solar Panels, Mono-crystalline Solar Panels, and Thin Film Solar Panels. For future work, this proposed pre-design is recommended for fabrication. A numerical study was carried-out on eight city locations in China by tracing their horizontal and vertical longitudinal, latitudinal lines noting the date, time and sunlight feeding of temperatures in the Celsius scale with the help of simulation and modeling tools like CFD, ANSYS FLUENT software, mesh geometry tools, and by using the Navier-Stokes and Continuity equations by fluid flow discharge rate, mass flow, water temperature and dropping of temperature, radiation working mechanisms, dimensions of water flowing tubes and absorber plates, density, the velocity of water as the working fluid, the viscosity of water in a cold and hot state as a process of Pre-design. Work also focuses on the comparison between flat plate collector and curved plate collector radiant sunlight absorption, As end result it is found the Curved plate collector produces 22% more elevated heat of outgoing water than flat plate collector.

Download Full-text

Experimental investigation of the effect of using water and ethanol as working fluid on the performance of pyramid-shaped solar still integrated with heat pipe solar collector

Solar Energy ◽

10.1016/j.solener.2020.06.032 ◽

2020 ◽

Vol 207 ◽

pp. 10-21 ◽

Cited By ~ 3

Author(s):

Rasoul Fallahzadeh ◽

Latif Aref ◽

Nabiollah Gholamiarjenaki ◽

Zeinab Nonejad ◽

Mohammadreza Saghi

Keyword(s):

Experimental Investigation ◽

Heat Pipe ◽

Solar Collector ◽

Working Fluid ◽

Solar Still

Download Full-text

Design Considerations for Heat-Pipe Solar Receivers

Journal of Solar Energy Engineering ◽

10.1115/1.2930476 ◽

1990 ◽

Vol 112 (3) ◽

pp. 169-176 ◽

Cited By ~ 2

Author(s):

Douglas R. Adkins

Keyword(s):

Solar Energy ◽

Heat Pipe ◽

Focal Point ◽

Liquid Sodium ◽

Working Fluid ◽

Concentrated Solar Energy ◽

Stirling Engines ◽

Parabolic Dish ◽

Parabolic Dish Concentrator ◽

Solar Receiver

Heat pipes are being developed to transfer solar energy from the focal point of a parabolic dish concentrator to the working fluid of Stirling engines. With these receivers, concentrated solar energy that is absorbed on the concave surface of a dome is removed by the evaporation of liquid sodium on the convex side of the dome. Vaporized sodium then condenses on an engine’s heater tubes and transfers energy to the working fluid of the engine. The condensed sodium returns to the absorber surface where it is redistributed across the dome by the capillary action of a wick. Issues concerning the flow of sodium in a heat-pipe solar receiver are investigated in this paper. A comparison is made between various wick options, and general issues concerning the design of heat-pipe receivers are also discussed.

Download Full-text

Numerical Optimization of a Cogenerating Parabolic Solar Collector Receiver

Volume 10: Heat Transfer, Fluid Flows, and Thermal Systems, Parts A, B, and C ◽

10.1115/imece2008-67915 ◽

2008 ◽

Cited By ~ 1

Author(s):

Catalina Gonzalez ◽

Jinny Rhee

Keyword(s):

Heat Transfer ◽

Solar Energy ◽

Solar Collector ◽

Photovoltaic Cells ◽

Electricity Consumption ◽

Photovoltaic System ◽

Working Fluid ◽

Electrical Efficiency ◽

Solar Systems ◽

Electricity Costs

The motivation for this study comes from the need for a clean, renewable energy source, which is greater now more than ever to reduce the country’s dependence on fossil fuels. Cogenerating solar systems can provide heat and electricity for many industrial applications such as power generation and absorption refrigeration systems. For example, data centers that run on conventional refrigeration systems are one of the largest electricity consumers in the nation, accounting for 1.2% of the total electricity consumption in 2005. This electricity consumption, almost half of which is used to run the data center’s air conditioning units, translates to $2.7 billion in electricity costs for that year. Using cogenerating solar systems for these types of applications could represent a significant amount of savings in electricity costs. The objective of this paper is to numerically optimize a receiver for a cogenerating photovoltaic and thermal parabolic solar collector that will produce both heat and electricity. The solar cogeneration system studied will convert solar energy into both heat and electricity by using a combination of photovoltaic cells, a parabolic trough thermal collector, and water as the liquid heat exchanger on the photovoltaic cells. The peak electrical efficiency of the multi-junction gallium arsenide Spectrolab photovoltaic cells used in this study is about 32%, with the rest of the solar energy being absorbed as heat. These temperature gains in the cells can lead to a decrease in efficiency. However, in cogenerating systems, water is used as a working fluid to remove heat from the photovoltaic cells, thus aiding in increasing the electrical efficiency of the photovoltaic system as well as increasing the thermal energy gained from the solar thermal collector. The numerical analysis for this project will use Flotherm, a CFD tool used to solve fluid and thermal problems. A single-phase water cooled square duct receiver subjected to non-uniform heating will be analyzed in Flotherm to determine the optimal parameters for the best convection heat transfer between the working fluid and the photovoltaic cells. To enhance the heat transfer between photovoltaic cells and working fluid, the inner surface of the receiver tube receiving the heat flux will be improved by adding fins to increase heat transfer and induce turbulent flow. The initial receiver design will be compared with other receivers to determine the optimal design. Results will be presented parametrically for a range of flow rates and receiver geometry.

Download Full-text

Thermochemical Conversion of Biomass Using Solar Energy: Use of Nanoparticle-Laden Molten Salt as the Working Fluid

ASME 2009 3rd International Conference on Energy Sustainability, Volume 2 ◽

10.1115/es2009-90039 ◽

2009 ◽

Cited By ~ 2

Author(s):

Himanshu Tyagi ◽

Patrick E. Phelan ◽

Ravi S. Prasher

Keyword(s):

Solar Radiation ◽

Solar Energy ◽

Molten Salt ◽

Concentration Factor ◽

Solar Collector ◽

Energy Use ◽

Operating Conditions ◽

Thermochemical Conversion ◽

Working Fluid ◽

Fluid Mixture

Solar energy can potentially be used to convert biomass into more readily usable fuel. The use of solar energy in such a process improves the overall conversion efficiency of the system significantly by eliminating combustion of a portion of biomass needed to heat the rest of it to a temperature where pyrolysis occurs. The present study models the thermochemical conversion process during pyrolysis of biomass matter into product gases. Concentrated solar radiation is used as the source of heating of the biomass. The biomass is indirectly heated by a mixture of molten salts (Na2CO3 and K2CO3) and nanoparticles (copper), which acts as the absorbing medium and in turn heats the biomass matter (cellulose). A two-stage heat transfer and chemical reaction analysis is carried out in order to simulate the simplified operating conditions of a solar-powered gasifier. The temperature of the molten salt at the exit of the reactor is held fixed at 1000 K (727°C). The calculations are carried out at different values of solar concentration factor ranging from 10 to 60. The results show that the temperature of the molten salt mixture at the exit of the solar collector increases with an increase in the solar concentration factor. Moreover the temperature inside the biomass reactor is a function of the concentration factor as well and largely the determining factor of the rate of biomass conversion into product gases. At the highest concentration factor (Cf = 60), the model predicts that the reactor is able to convert 1.1 tons of biomass into product gases each hour using 900 kW of solar radiation at an overall efficiency of 8%. The main finding of this study is that under similar operating conditions a solar collector using a direct absorption fluid (mixture of nanoparticles and molten salt) would require significantly less concentration factor (an order of magnitude reduction) than a conventional solar collector. A conventional solar collector is defined as one where the solar radiation heats up a solid surface (such as tube walls) which in turn heats up the working fluid (molten salt). Such a reduction in concentration factor would translate into lower concentrator area, and consequently lower initial capital cost.

Download Full-text

System Design of Testing System for Truck-Mounted Solar Collector

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.562-564.578 ◽

2012 ◽

Vol 562-564 ◽

pp. 578-582

Author(s):

Yuan Chao Deng ◽

Yu Ning Zhong ◽

Tao He

Keyword(s):

Solar Energy ◽

Heat Pipe ◽

Solar Collector ◽

System Stability ◽

Testing System ◽

Solar Collectors ◽

Water Heaters ◽

Reduced Volume ◽

Solar Water Heaters ◽

Force Calculation

The truck-mounted solar collector testing system is a flexible and convenient testing device. However design of thus a system is much more difficult than that of the fixed solar collector testing system, because it needs consideration in every respect so as to make sure the following: accurate testing, accommodation of the reduced volume of the testing system, stability of the testing system, addition of a removable device and so on. This article explores the systematic design of the truck-mounted solar collector testing system, points out the design issues to be considered, propose an appropriate design plan, and finally conducts the main force calculation. Solar energy is one of the cleanest sources; it is green and pollution-free. Today, environmental pollution is getting worse and worse; thus application of solar energy is becoming more extensive. A solar collector is defined as any of various devices that absorb the solar radiation and deliver the heat energy to the medium of heat transfer device. Solar collectors are not a direct consumer-oriented product, but key components that form various solar thermal systems, such as solar water heaters, solar energy dryers, solar industrial heaters and so on, of which the solar collectors are a core part of the system. At present solar heat pipe collectors and collector plates are the two most widely used products of solar collectors. Factory productions of such products are subject to inspection before they can be put on the market. Currently product testing of this kind is performed collectively in fixed locations; consequently, it is vulnerable to the geographical conditions, climate changes, and other factors in the location. A truck-mounted solar collector testing system is a system that integrates both testing systems, heat pipe collectors and collector plates, in a vehicle, which can be driven into the manufacturers that produce heat pipes and/or heat plates or other places where testing conditions can be met according to the requirements. By doing so, the problems associated with the fixed testing system can be solved. However, design of truck-mounted type solar collector testing system is much more difficult than that of fixed solar collector testing system. In addition to testing accuracy, it must also take the reduced volume of the testing system into account to ensure that the system can be accommodated into a smaller space of the vehicle. Furthermore, the stability of the testing system must be assured. Finally a removable device needs to be added to the system for convenience. In the following, we show our design of the truck-mounted solar collector testing system and calculations for the related stress analysis.

Download Full-text