A Comparative Study on the Performances of Flat Plate and Evacuated Tube Collectors Deployable in Domestic Solar Water Heating Systems in Different Climate Areas
TL;DR: In this paper, a comparison of the energy performances of flat-plate collectors and evacuated-tube collectors in domestic solar water heating systems located in different climate areas was carried out in order to ascertain solar energy utilization.
Abstract: Using TRNSYS software, a comparison of the energy performances of flat-plate collectors (FPCs) and evacuated-tube collectors (ETCs) in domestic solar water heating systems located in different climate areas was carried out in order to ascertain solar energy utilization. Investigations were carried out on single FPCs and ETCs and also for strings of four panels connected in series. Tests were conducted using simulations for water as heat transfer fluid with a fixed fluid flow rate and varying the temperature of the collector’s returning fluid. The maximum power peak decreases with the increase in the inlet temperature of the fluid to the collector in the FPC. The maximum outlet temperature of the FPC is higher than the ETC, most of the time. The evacuated-tube collector performs better only in cold climate areas. Simulations suggest that the use of the FPC is strongly discouraged in cold climatic areas due to thermal losses, whereas the ETC works well with reduced dispersion of heat. In warm seasons, on the contrary, the FPC takes advantage of the high environmental temperature which heats the fluid. The maximum yearly outlet temperature and useful power peak predicted in different climatic areas were investigated by varying the temperature of the fluid inlet fed to the two strings of four FPCs and ETCs. In all cases, the outlet temperature is higher in the ETC technology.
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TL;DR: In this paper, the efficiency factors of a flat-plate solar heat collector as a heat exchanger are derived for various types of collectors, together with graphical data and examples of their use.
Abstract: All variables influencing the efficiency of a flat-plate solar heat collector as a heat exchanger can be combined into a single “efficiency factor.” These efficiency factors are more or less design constants of the particular collector design, and are only slightly influenced by operating conditions. Consequently they are extremely convenient for use in accurate design and performance calculations. The full mathematical derivations are presented for several of these efficiency factors for various types of collectors, together with graphical data and examples of their use.
29 citations
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Abstract: Nowadays, air conditioning consumes, on average, around one-fifth of the total power used in buildings globally. The present paper aims to provide the present status on the employment of Earth-to-Air Heat eXchangers (EAHX) to contain the consumption of energy and to reduce the effect on the environment in response to the Montreal and Kyoto protocols in a way to achieve cleaner energy production with a low Global Warming Potential (GWP) and a low ozone depletion potential (ODP). Different peculiarities and applications (direct or hybrid) are critically analyzed and reviewed. Specifically, in this paper, the different hybrid applications presented in the literature, where the Earth-to-Air Heat eXchangers are coupled to advanced systems, are reviewed. Finally, an IoT-based EAHX control system plan is reported and discussed to optimize energy efficiency and thermal comfort to suit operating conditions under different time zones.
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10 citations
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TL;DR: In this paper, the merits and demerits of solar energy technologies are both discussed and a number of technical problems affecting renewable energy research are also highlighted, along with beneficial interactions between regulation policy frameworks and their future prospects.
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1,331 citations
"A Comparative Study on the Performa..." refers background in this paper
...The results obtained were proof that solar heat is a competitive alternative to fossil fuels, reducing CO2 emissions and providing a positive economic performance [21,38]....
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Book•
12 Nov 2012
490 citations
"A Comparative Study on the Performa..." refers methods in this paper
...Through photovoltaic panels, solar energy is utilized for generating electric power [24,25]....
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TL;DR: In this paper, the efficiency factors of a flat-plate solar heat collector as a heat exchanger are derived for various types of collectors, together with graphical data and examples of their use.
347 citations
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Abstract: Global warming is one of the major consequences of the human activities where the overuse of fossil fuels as energy resources caused the increase in the concentration of the greenhouse gases (GHGs), such as CO2, CH4, N2O, and water vapor, in the atmosphere causing the increase in the average surface temperature of the earth. This article reviews the driving forces of global warming and highlights the major contributors to this phenomenon and presents some of the mitigation techniques. Water vapor is responsible for two-third of the global warming; however, CO2 is considered as the controlling factor of the global warming. In other words, if the concentration of CO2 did not increase, global warming would not have happened. Scientists claim that doubling or halving the CO2 in the atmosphere causes the change in the average surface temperature of the earth by +3.8 C or −3.6 C, respectively. However, this amount of change depends on the change in the humidity of the air which in return depends on the air’s temperature. Conversely, even though the other GHGs such as CH4 and N2O have stronger ability to absorb the radiation, their contribution in the global warming is insignificant because of their low concentration in the atmosphere compared with CO2. The adoption of the mitigation and adaptation strategies at the same time is the most effective economic and technical solution for the global warming issue. © 2018 American Institute of Chemical Engineers Environ Prog, 2018
301 citations
"A Comparative Study on the Performa..." refers background in this paper
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TL;DR: In this article, a standard glazed flat plate collector and an evacuated tube collector are installed in parallel and tested at the same working conditions; the evacuated collector is a direct flow through type with external compound parabolic concentrator (CPC) reflectors.
285 citations