The effect of the wind conditions on the thermal performance of an unglazed solar thermal collector

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21720%2F23%3A00369046" target="_blank" >RIV/68407700:21720/23:00369046 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1016/j.egyr.2023.09.132" target="_blank" >https://doi.org/10.1016/j.egyr.2023.09.132</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.egyr.2023.09.132" target="_blank" >10.1016/j.egyr.2023.09.132</a>

Jazyk výsledku

angličtina

Název v původním jazyce

The effect of the wind conditions on the thermal performance of an unglazed solar thermal collector

Popis výsledku v původním jazyce

The paper presents a theoretical analysis performed for unglazed liquid solar thermal collectors (USTCs) to demonstrate the magnitude of the thermal performance uncertainty caused by the different wind conditions under the same wind speed. The literature currently comprises more than 90 combined convection heat transfer correlations. The difference between them is primarily caused by the difference in wind characteristics during the experiment (wind turbulence level, wind direction, etc.). A detailed validated theoretical model of a USTC and forty applicable combined convection heat transfer correlations were used to perform the analysis to demonstrate the magnitude of the thermal performance uncertainty caused by the different wind conditions. It was found that, for the low operating temperature, the uncertainties caused by the different wind conditions are ± 4 %, ± 6 %, and ± 8.5 % under wind speeds of 0 m/s, 1.5 m/s, and 3 m/s, respectively. These values are relatively small compared to the obtained average thermal performance values of 78 %, 73 %, and 65 %. In contrast, the uncertainty values are significant for relatively high operation temperatures: ± 11.5 %, ± 16.5 %, and ± 22 %, while the modelled efficiency values for these operating conditions are 15 %, 30 %, and 44 %. The analysis demonstrated that the difference in wind characteristics under the same wind speed significantly affects a USTC’s thermal performance. From a practical standpoint, the USTC’s thermal performance in real wind conditions may exhibit significant disparities compared to its performance tested in controlled laboratory conditions under the same wind speed. Furthermore, notably varied thermal performance can be expected for identical USTCs installed in different locations under the same wind speed due to the different wind characteristics (wind turbulence level, wind direction, etc.).

Název v anglickém jazyce

The effect of the wind conditions on the thermal performance of an unglazed solar thermal collector

Popis výsledku anglicky

The paper presents a theoretical analysis performed for unglazed liquid solar thermal collectors (USTCs) to demonstrate the magnitude of the thermal performance uncertainty caused by the different wind conditions under the same wind speed. The literature currently comprises more than 90 combined convection heat transfer correlations. The difference between them is primarily caused by the difference in wind characteristics during the experiment (wind turbulence level, wind direction, etc.). A detailed validated theoretical model of a USTC and forty applicable combined convection heat transfer correlations were used to perform the analysis to demonstrate the magnitude of the thermal performance uncertainty caused by the different wind conditions. It was found that, for the low operating temperature, the uncertainties caused by the different wind conditions are ± 4 %, ± 6 %, and ± 8.5 % under wind speeds of 0 m/s, 1.5 m/s, and 3 m/s, respectively. These values are relatively small compared to the obtained average thermal performance values of 78 %, 73 %, and 65 %. In contrast, the uncertainty values are significant for relatively high operation temperatures: ± 11.5 %, ± 16.5 %, and ± 22 %, while the modelled efficiency values for these operating conditions are 15 %, 30 %, and 44 %. The analysis demonstrated that the difference in wind characteristics under the same wind speed significantly affects a USTC’s thermal performance. From a practical standpoint, the USTC’s thermal performance in real wind conditions may exhibit significant disparities compared to its performance tested in controlled laboratory conditions under the same wind speed. Furthermore, notably varied thermal performance can be expected for identical USTCs installed in different locations under the same wind speed due to the different wind characteristics (wind turbulence level, wind direction, etc.).

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

20704 - Energy and fuels

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2023

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Energy Reports

ISSN

2352-4847

e-ISSN

—

Svazek periodika

10

Číslo periodika v rámci svazku

November

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

9

Strana od-do

2880-2888

Kód UT WoS článku

001085973400001

EID výsledku v databázi Scopus

2-s2.0-85172232916