Validation and modification of modeling thermally activated building systems (TABS) using EnergyPlus
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EnergyPlus (EP) integrates a low temperature radiant system module to evaluate thermal performance of radiant systems such as thermally activated building systems (TABS), but the assumptions in this module neglect thermal resistance of the pipe and thermal resistance between the pipe exterior surface and the pipe level, which may result in the inaccurate evaluation of TABS in terms of surface temperature and surface heat flow. In this paper, in order to validate this module used in EP, steady and transient heat transfer processes of TABS in buildings were studied by analytical solution, two-dimensional numerical simulation and EP simulation. The comparison shows that the assumptions indeed result in a largely overestimated cooling and heating capacity of TABS. In order to improve this radiant module, a simple solution of introducing a no mass material layer with the neglected thermal resistances to both sides of the pipe level was proposed. With this method, the results of mean surface temperature and mean heat flow show good agreement with that from analytical solution as well as numerical simulation. Furthermore, the results of the simulation coupling the modified module with room systems show very small deviation from the results found in the literature. In addition, the application of the modified module in a hollow core concrete deck structure with TABS was investigated.
Keywordsthermally activated building systems EnergyPlus low temperature radiant system module thermal resistance modified simulation
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- Chantrasrisalai C, Ghatti V, Fisher DE, Scheatzle DG (2003). Experimental validation of the EnergyPlus low-temperature radiant simulation. ASHRAE Transactions, 109(2): 614–623.Google Scholar
- EnergyPlus (2012). EnergyPlus Manual, Documentation Version 7.2. US Department of Energy, USA.Google Scholar
- Fort K (2001). TYPE 360: Floor Heating and Hypocaust. Available: http://www.trnsys.de/download/de/ts_type_360_de.pdf.Google Scholar
- Koschenz M, Lehmann B (2000). Thermoaktive Bauteilsysteme Tabs. EMPA Energiesysteme/Haustechnik, Zurich. (in German)Google Scholar
- Olesen BW, Bonnefoi F, Michel E, Carli MD (2000). Heat exchange coefficient between floor surface and space by floor cooling: Theory or a question of definition. ASHRAE Transactions, 106(1): 684–694.Google Scholar
- Olesen BW, Sommer K, Düchting B (2002). Control of slab heating and cooling systems studied by dynamic computer simulations. ASHRAE Transactions, 108(2): 698–707.Google Scholar
- Olesen BW (2008). Radiant floor cooling systems. ASHRAE Journal, 50(9): 16–20.Google Scholar
- Strand RK, Pedersen CO (1994). Analytical verification of heat source transfer functions. Presented at first Joint Conference of International Simulation Societies, Zurich, Switzerland.Google Scholar
- Strand RK (1995). Heat source transfer functions and their application to low temperature radiant heating systems. PhD Dissertation, Department of Mechanical and Industrial Engineering, University of Illinois at Urbana-Champaign, USA.Google Scholar
- Strand RK, Pedersen CO (2002). Modeling radiant systems in an integrated heat balance based energy simulation program. ASHRAE Transaction, 108(2): 979–988.Google Scholar