scholarly journals Solar Collectors Based оn Copper Two-Phase Thermosyphons

Author(s):  
V. I. Marynenko ◽  
V. S. Kulynych

Thermosyphons and heat pipes offer great opportunities for creating pas sive heat and mass transfer systems. Various design solutions using heat pipes (thermosyphons) in solar energy systems are known. Solar energy is one of the promising energy sources, a step towards reducing dependence on other energy resources. To date, there is already an industrial production of solar collectors based on thermosyphons (heat pipes). In solar collectors, the use of thermosyphons (heat pipes) makes it possible to simplify the assembly of the structure, ensures its high modularity, maintainability and reliability. In the course of research, the authors have developed and justified the design of a solar collector based on thermosyphons fixed on panels that absorb solar rays. In order to analyze the efficiency of the solar collector based on two-phase copper thermosyphons, two models of solar collectors were created, viz. the one with a flat absorbing panel and the one with a cylindrical absorbing panel. The areas of the absorbing surfaces were the same. Both models were studied by the method of thermophysycal experiment. The results of studies of the effectiveness of the above-mentioned solar collectors have been obtained. The efficiency of the solar collector based on a copper two-phase thermosyphon, which is fixed on a cylindrical absorbing panel is 2–5 % more than the efficiency of the solar collector based on a copper two-phase thermosyphon, which is fixed on a flat absorbing panel. The maximum efficiency value obtained at low initial water temperatures for solar collectors with a cylindrical and flat absorbing surface was 60 %.

Author(s):  
Ahmad Fudholi ◽  
Kamaruzzaman Sopian

<span>Among the most important components of solar energy systems, solar collectors are devices that receive solar energy and convert it into thermal energy, as most essential components of solar dryer. This review presents description and previous work performed on performances of solar air collector for agricultural produce. In addition, various solar collectors are classified and described. Solar air collectors for drying application of agricultural produce are presented and summarize. The energy and exergy efficiency of the solar air collector ranges from 28% to 62% and from 30% to 57%, respectively. </span>


Author(s):  
N. Jayanthi ◽  
M. Venkatesh ◽  
R. Suresh Kumar ◽  
S. Sekar

Energy from the Sun brings as Solar energy which is abundantly available and utilized for various applications. Owing to the increase in energy demand, having a limit of non-renewable energy sources, more interest is given to Solar energy. One of the most fundamental applications of using Solar energy is a Solar collector. The efficiency of the Solar collector depends upon the fluids used in the Solar collector and thermal performance also can be enhanced by using heat pipes in the Solar collector. Compared to flat plate solar collectors, the major disadvantage of heat loss can be rectified in heat pipe solar collectors. Still, to improve the performance of heat pipe solar collectors, nanofluids can be used instead of base fluids to improve thermal performance. In this review paper, the application of nanofluid in Solar collectors results in the percentage of improvement in heat transfer by nanofluid at optimum condition is discussed. This paper reviewed widely the recent development and upcoming research that can be done to enhance the working of heat pipe Solar collectors using nanofluids.


2014 ◽  
Vol 899 ◽  
pp. 199-204
Author(s):  
Lukáš Skalík ◽  
Otília Lulkovičová

The energy demand of buildings represents in the balance of heat use and heat consumption of energy complex in the Slovak national economy second largest savings potential. Their complex energy demands is the sum of total investment input to ensure thermal protection and annual operational demands of particular energy systems during their lifetime in building. The application of energy systems based on thermal solar systems reduces energy consumption and operating costs of building for support heating and domestic hot water as well as savings of non-renewable fossil fuels. Correctly designed solar energy system depends on many characteristics, i. e. appropriate solar collector area and tank volume, collector tilt and orientation as well as quality of used components. The evaluation of thermal solar system components by calculation software shows how can be the original thermal solar system improved by means of performance. The system performance can be improved of more than 31 % than in given system by changing four thermal solar system parameters such as heat loss coefficient and aperture area of used solar collector, storage tank volume and its height and diameter ratio.


1983 ◽  
Vol 105 (4) ◽  
pp. 440-445 ◽  
Author(s):  
J. Ribot ◽  
R. D. McConnell

We developed an integral heat-pipe/evacuated-tube solar collector in which the inner receiver tubes form the evaporator sections of glass heat pipes. This paper describes both theoretical analyses and empirical tests, comparing the performance of the glass heat-pipe solar collector with one of today’s high efficiency evacuated-tube solar collectors. The comparison demonstrates that the performance of the two collectors is effectively identical. The testing and analysis indicate that the glass-wick-type glass heat pipe is an effective heat transfer system for evacuated-tube solar collectors.


Author(s):  
Pawel Olszewski

Humankind can effectively utilize only part of the solar energy reaching a surface of the Earth. It is due to the low density of the solar radiation and its unfavorable distribution. The majority of solar energy falls to the low latitude countries, where space-heating requirements are marginal. In these countries the solar heat is used for preparing water for washing or cleaning purposes, and this process works in one, or — maximum — a few daily cycles. In countries located at higher latitudes, where space heating is necessary in cold months, the current solar energy is insufficient to meet the space heating demand. The heat storage in deep layer of the ground is the one of possible way for solution of this problem. During the heating season, energy storage is discharged supplying the heat pomp cooperating with domestic heating system and during the summer months the storage can be charged by fluid heated in solar collectors. The main aim of presented research was analysis of using the ground layer as a heat storage system in the countries located in higher latitudes. The first variable taken into consideration was the output temperature of water leaving the solar collectors. The temperature distribution in the ground depends on the inlet water temperature, primary heated in the solar collectors, and forced into vertical boreholes. The temperature field in the ground was calculated using the duFort-Frankel finite-difference numerical method. A numerical code for 3D time dependent storage simulation has been created. The next step of analysis was calculation of waters’ temperature at the borehole output during cold months when the ground storage is discharged. This water works as a low-temperature reservoir of the heat pomp supplying the dwelling heating system. The solution of the problem is focused on an optimization of all parameters for the most efficient utilization of energy stored in the ground. The numerical genetic algorithms are scheduled to use to achieve this target.


Author(s):  
Anna Maria Klepacka

The paper emphasizes the differences in the concentration of investments with the use of photovoltaic panels and solar collectors in voivodships with significant potential for using solar energy. The subject of the paper addresses, among others, the significant changes in renewable energy sources (RES) and EU subsidies that affect the economics of solar micro-installations in Poland. The study applied data from the Ministry of Agriculture and Rural Development, which included completed operations under the rural development program (RDP) for the period 2007-2013. The percentage share of the number of photovoltaic panel installations in Lubelskie and Mazowieckie Voivodships constituted 22% of that type of investments in the country (13% and 9% respectively, with a total capacity of 2,634 kW). However, in the case of the number of solar collector installations, the percentage share in Lubelskie and Mazowieckie Voivodships accounted for 44% of such installations in Poland (29% and 15%, respectively, with a total capacity of 4,239 kW). The results confirm the view that the location is an important determinant of photovoltaic panel and solar collector installations in Poland as shown in the examined voivodships characterized by the favorable solar radiation conditions.


2015 ◽  
Author(s):  
Singiresu S. Rao

The optimum design of stationary flat-plate solar collectors is considered using the game theory approach for multiple objectives. The clear day solar beam radiation and diffuse radiation at the location of the solar collector are estimated. Three objectives are considered in the optimization problem formulation: maximization of the annual average incident solar energy, maximization of the lowest month incident solar energy and minimization of the cost. The game theory solution represents the best compromise in terms of the supercriterion selected. Because some design parameters such as solar constant, altitude, typical day of each month and most of the design variables are not precisely known, a probabilistic approach is also proposed in this work. The results obtained by the determinist and probabilistic approaches are compared. It is found that the absolute value of each objective function decreases with an increase in either the probability of constraint satisfaction or the coefficient of variation of the random variables. This work represents the first work aimed at the application of multi-objective optimization strategy, particularly the game theory approach, for the solution of the solar collector design problem.


2012 ◽  
Vol 562-564 ◽  
pp. 578-582
Author(s):  
Yuan Chao Deng ◽  
Yu Ning Zhong ◽  
Tao He

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.


Author(s):  
Mangesh Gupta ◽  
Ram Bilas Prasad

Solar energy is clean and easily available everywhere. It is trapped by a device called a solar collector. Solar collectors are used to utilize solar energy. Generally, the performances of the solar collector are low. Nanofluid is used in solar collectors to boost up the performance of the solar collector. This paper presents a review of the literature on the role of nanofluids in various types of solar collectors. It is found that the performance of the solar collector improves by using nanofluids as a heat transfer medium.


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