scholarly journals Theoretical and Experimental Investigations of Cylindrical Air-Heating Solar Collector

2016 ◽  
Vol 53 (3) ◽  
pp. 11-21
Author(s):  
I. Pelece ◽  
P. Shipkovs

Abstract Solar energy is used not only at low latitudes, where it is available at large amounts, but also at higher latitudes, where height of sun and irradiance are significantly lower. On the other hand, the length of day at higher latitudes is longer in summer than at low latitudes, and also the path of the sun is longer. The present research deals with seeking for new shapes of solar collectors capable of receiving more solar energy. For designing and evaluating new shapes of solar collectors, it is necessary to have new methods for simple calculations of energy received from the sun by surface of any shape and direction. Such a method is explained in the present paper. Based on calculations by the proposed method, a new form of solar collector – a cylindrical collector – has been worked out. This collector is intended for air heating, but main principles can also be used for water heating, and even for photovoltaics. A cylindrical collector receives more energy in the morning and evening than a flat one, but at midday power of both collectors is equal, if effective areas are equal. Daily energy sum of the cylindrical solar collector is 1.5 times greater than that of the flat one.

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4454
Author(s):  
Tong Liu ◽  
Li Liu ◽  
Yufang He ◽  
Mengfei Sun ◽  
Jian Liu ◽  
...  

Solar energy has been extensively used in industry and everyday life. A more suitable solar collector orientation can increase its utilization. Many studies have explored the best orientation of the solar collector installation from the perspective of data analysis and local-area cases. Investigating the optimal tilt angle of a collector from the perspective of data analysis, or guiding the angle of solar collector installation, requires an a priori theoretical tilt angle as a support. However, none of the current theoretical studies have taken the real motion of the Sun into account. Furthermore, a complete set of theoretical optimal tilt angles for solar energy is necessary for worldwide locations. Therefore, from the view of astronomical mechanics, considering the true orbit of the Sun, a mathematical model that is universal across the globe is proposed: the Kepler motion model is constructed from the solar orbit and transformed into the local Earth coordinate system. After that, the calculation of the optimal tilt angle solution is given. Finally, several examples are shown to demonstrate the variation of the optimal solar angle with month and latitude. The results show that for daily fixed solar collectors, the altitude angle of the collector should be about 6° above the noon solar altitude angle in summer and 6° lower in winter. For annual fixed collectors, the tilt angle should be slightly higher than the latitude. In summary, this study demonstrates that when a location is specified, this model can be used to calculate the theoretical optimum tilt angle of solar collectors for that position.


Author(s):  
Enrico Zambolin ◽  
Davide Del Col ◽  
Andrea Padovan

New comparative tests on different types of solar collectors are presented in this paper. Tests have been performed at the solar energy conversion laboratory of the University of Padova. Two standard glazed flat plate collectors and one evacuated tube collector are installed in parallel; the evacuated collector is a direct flow through type with external CPC (compound parabolic concentrator) reflectors. The present test rig allows to make measurements on the flat plate, on the evacuated collector or on both simultaneously, by simply acting on the valves to modify the circuit. In this paper measurements of the performance of the evacuated tube collector and flat plate collectors working at the same conditions are reported. Efficiency in stationary conditions is measured following the standard EN 12975-2 [1] and it is compared with the input/output curves measured for an entire day. The main purpose of the present work is to characterize and to compare the daily energy performance of the two types of collectors. An effective mean for describing and analyzing the daily performance is the so called input/output diagram, in which the collected solar energy is plotted against the daily incident solar radiation. Test runs have been performed in several conditions to reproduce different conventional uses (hot water, space heating, solar cooling).


POROS ◽  
2017 ◽  
Vol 14 (1) ◽  
pp. 28
Author(s):  
Ivan Budiman ◽  
I Made Kartika ◽  
Abrar Riza

Abstract: Warm water is needed by human being to take a bath, wash their clothes, their dishes etc. By the photothermal conversion, the solar energy can be used to heat the water. Flat solar collector is a tool which is used to capture energy of the sun radiation then convert it into heat to heat up water in collector’s pipes. The number of glass cover used effects the performance and efficiency of the collector. From this research, it is found that the efficiency of the collector is better when the cover used are two glasses than one glasses. The temperature difference of incoming and outgoing water in the collector using two glasses 15 ̊C higher than that of one glass. 


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):  
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.


2021 ◽  
Vol 2021 (2) ◽  
pp. 53-55
Author(s):  
Yu.M. Matsevytyi ◽  
◽  
M.O Safonov ◽  
Y.M. Bushtets ◽  
◽  
...  

Spherical solar tubular collector (SSTK) was invented in A. Pidgorny IPMash. as an alternative to the solar flat collector to convert the radiant energy of the Sun into heat. To understand the efficiency of a collector, it is important to know how much energy it can take. A methodology for calculating the amount of heat perceived by the collector has been developed. The surface area of a spherical tubular collector illuminated by the Sun using proposed methodology was determined. The amount of heat received by the solar collector for each day of the year was estimated. The total amount of heat received by SSTK in Kharkiv during the year was defined. Keywords: solar energy, spherical solar tubular collector, amount of heat


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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