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Title:New technique to evaluate the overall heat loss coefficient for a flat plate solar collector
Authors:ID Bouhdjar, Amor (Author)
ID Semai, Hakim (Author)
ID Amari, Aissa (Author)
Files:.pdf New_technique_to_evaluate_the_overall_heat_loss_coefficient_Bouhdjar_2021.pdf (2,67 MB)
MD5: FBA3B942EAE08F5A2155A6D2A90864B2
 
URL https://www.fe.um.si/e-jet/44-2021-1/2717-april-2021.html
 
Language:English
Work type:Scientific work
Typology:1.01 - Original Scientific Article
Organization:FE - Faculty of Energy Technology
Abstract:Low-temperature solar systems mostly use flat plate solar collectors. Good design and correct dimensioning of a solar heat generator are based on precise knowledge of the characteristics of the flat plate solar collector on site. The present work considers a flat plate solar air collector, a flat plate solar water collector, and a flat plate solar water collector with air absorber cooling. The investigation intends to shed light on a procedure to determine the overall heat loss coefficient and the heat removal factor using recorded system temperatures, operating parameters, and environmental data. The Hottel-Whillier-Bliss equation gives the collector useful energy. This expression is used to generate a correlation for the collector efficiency through a linear fitting. We calculate the overall heat loss coefficient of the collector from the slope of the collector efficiency curve. However, we need to know the heat removal factor of the collector. In this study, we present a new technique to calculate the heat removal factor. Then we deduce the collector overall heat loss coefficient. Results show that, very often, the overall heat loss coefficient for the flat plate solar air collector and the flat plate solar water collector determined with this new method is higher than the one calculated with the empirical formula proposed by Klein. However, the experimental overall heat loss coefficient for the flat plate solar water collector with air absorber cooling is smaller than the one calculated with the empirical formula proposed by Klein. The analysis shows that the overall heat loss coefficient determined with the new technique seems more realistic since all phenomena occurring during the heat transfer from solar irradiance incident on the absorber plate and transmitted to the transport fluid are considered.
Keywords:flat plate solar collector, overall heat loss coefficient, heat removal factor
Publication status:Published
Publication version:Version of Record
Publication date:01.04.2021
Publisher:Fakulteta za energetiko Univerze v Mariboru
Year of publishing:2021
Number of pages:str. 11-25
Numbering:letn. 14, št. 1
PID:20.500.12556/DKUM-86305 New window
UDC:621.311.243
ISSN on article:1855-5748
COBISS.SI-ID:66330627 New window
Publication date in DKUM:10.11.2023
Views:423
Downloads:94
Metadata:XML DC-XML DC-RDF
Categories:Misc.
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Record is a part of a journal

Title:Journal of energy technology
Publisher:University of Maribor, University of Maribor Press, Fakulteta za energetiko
ISSN:1855-5748
COBISS.SI-ID:243311360 New window

Secondary language

Language:Slovenian
Title:Nova tehnika za oceno celotnega koeficienta toplotne izgube za ploščati sončni kolektor
Abstract:Nizkotemperaturni sončni sistemi večinoma uporabljajo sončne kolektorje z ravno ploščo. Dobra zasnova in pravilne dimenzije solarnega generatorja toplote temeljijo na natančnem poznavanju značilnosti ploščatega sončnega kolektorja na lokaciji. Pričujoče delo obravnava ravno zračni ploščati sončni kolektor, vodni ploščati sončni kolektor in ploščasti sončni kolektor vode z zračnim absorberjem. Analiza v članku namerava osvetliti postopek določanja celotnega koeficienta toplotnih izgub in faktorja odvajanja toplote z uporabo zabeleženih temperatur sistema, obratovalnih parametrov in okoljskih podatkov. Enačba Hottel-Whillier-Bliss daje raziskovalcem koristne informacije. Ta izraz se uporablja za ustvarjanje korelacije za učinkovitost kolektorja z linearno vgradnjo. Skupni koeficient toplotnih izgub kolektorja izračunamo iz naklona krivulje izkoristka kolektorja. Poznati pa moramo faktor odvajanja toplote kolektorja. V tej študiji predstavljamo novo tehniko za izračun faktorja odvajanja toplote. Nato izračunamo koeficient celotne toplotne izgube kolektorja. Rezultati kažejo, da je skupni koeficient toplotne izgube za ravno ploščasti zračni sončni kolektor in vodni ploščati sončni kolektor, določen s to novo metodo, večji od tistega, izračunanega z empirično formulo, ki jo je predlagal Klein. Vendar je eksperimentalni skupni koeficient toplotne izgube za vodni ploščni sončni kolektor z zračnim absorberjem manjši od tistega, izračunanega z empirično formulo, ki jo je predlagal Klein. Analiza kaže, da se zdi skupni koeficient toplotne izgube, določen z novo enačbo, bolj realen, saj so upoštevani vsi pojavi, ki se pojavijo med prenosom toplote zaradi sončnega obsevanja, ki vpade na ploščo absorberja in se prenese v transportno tekočino.
Keywords:ploščati sončni kolektor, koeficient celotne toplotne izgube, faktor odvajanja toplote


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  1. Journal of energy technology

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