Theoretical evaluation of night sky cooling in the Czech Republic

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216305%3A26110%2F14%3APU106904" target="_blank" >RIV/00216305:26110/14:PU106904 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S1876610214003373" target="_blank" >https://www.sciencedirect.com/science/article/pii/S1876610214003373</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.egypro.2014.02.075" target="_blank" >10.1016/j.egypro.2014.02.075</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Theoretical evaluation of night sky cooling in the Czech Republic

Popis výsledku v původním jazyce

Energy necessary for cooling of building in summer season makes a big part of energy required for building operation. Redundant heat removal in summer can be realized in various ways. One of possible methods, mainly in desert areas, is using thermal radiation against night sky. The paper deals with theoretical efficiency evaluation of night sky cooling in climatic condition of Czech Republic. The numerical simulations of non-steady heat transfer and internal thermal comfort evaluation in an office room has been performed. We have considered a cooling system consists of radiating panels placed on the roof, connected by pipes with the cooling ceiling in an office room. The radiating panel is used to cool down the cooling water by convection and heat radiation against the night sky. At first we processed the real hourly climatic data for city Brno and by using the extra-terrestrial solar irradiation we calculated night sky temperature during cloudy conditions and other necessary climate parameters for the long-term simulations. From this file of data, we selected seven typical combinations of equivalent sky temperatures, external air temperatures and wind velocities in order to cover the external conditions during the summer nights. Next we assumed a variable mean temperature of water flowing through the radiating panel in order to be able of computing its thermal performance. Then we carried out seven simulations of chosen radiating panel with these boundary conditions by means of computational fluid dynamics method (CFD) in the software Fluent. The data obtained were processed in the own software so we set the appropriate regression functions describing the thermal behaviour of radiating panel, which was then used for long-term thermal performance simulations in software TRNSYS. The multi zone model in TRNSYS links the building and its equipment with thermal the cooling ceiling model as well as with the water loop containing the radiating panels. This computer model

Název v anglickém jazyce

Theoretical evaluation of night sky cooling in the Czech Republic

Popis výsledku anglicky

Energy necessary for cooling of building in summer season makes a big part of energy required for building operation. Redundant heat removal in summer can be realized in various ways. One of possible methods, mainly in desert areas, is using thermal radiation against night sky. The paper deals with theoretical efficiency evaluation of night sky cooling in climatic condition of Czech Republic. The numerical simulations of non-steady heat transfer and internal thermal comfort evaluation in an office room has been performed. We have considered a cooling system consists of radiating panels placed on the roof, connected by pipes with the cooling ceiling in an office room. The radiating panel is used to cool down the cooling water by convection and heat radiation against the night sky. At first we processed the real hourly climatic data for city Brno and by using the extra-terrestrial solar irradiation we calculated night sky temperature during cloudy conditions and other necessary climate parameters for the long-term simulations. From this file of data, we selected seven typical combinations of equivalent sky temperatures, external air temperatures and wind velocities in order to cover the external conditions during the summer nights. Next we assumed a variable mean temperature of water flowing through the radiating panel in order to be able of computing its thermal performance. Then we carried out seven simulations of chosen radiating panel with these boundary conditions by means of computational fluid dynamics method (CFD) in the software Fluent. The data obtained were processed in the own software so we set the appropriate regression functions describing the thermal behaviour of radiating panel, which was then used for long-term thermal performance simulations in software TRNSYS. The multi zone model in TRNSYS links the building and its equipment with thermal the cooling ceiling model as well as with the water loop containing the radiating panels. This computer model

Druh

D - Stať ve sborníku

CEP obor

—

OECD FORD obor

20101 - Civil engineering

Projekt

<a href="/cs/project/EE2.3.30.0039" target="_blank" >EE2.3.30.0039: Excelentní mladí vědci na VUT v Brně</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2014

Kód důvěrnosti údajů

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

Název statě ve sborníku

2nd International Conference on Solar Heating and Cooling for Buildings and Industry (SHC 2013). Proceedings of a meeting held 23-25 September 2013, Freiburg, Germany.

ISBN

9781632663665

ISSN

1876-6102

e-ISSN

—

Počet stran výsledku

9

Strana od-do

645-653

Název nakladatele

Elsevier

Místo vydání

Amsterdam

Místo konání akce

Freiburg

Datum konání akce

23. 9. 2013

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

000345410700074