Thermal performance of a test cell in a hot and humid climate:
The impact of thermal insulation
P.H. Tan, U. Pont, V.Müller & A. Mahdavi
Department of Building Physics & Building Ecology
Vienna University of Technology
Title - 1/17
Content:
• Introduction
•
Overview || Climate || Research Questions || Literature
• Approach
•
Test Cells/“Calibration“||EIFS ||Monitoring ||Ventilation ||
•
Dynamics thermal simulation
• Results & Discussion
•
Temperature and relative Humidity || PMV & PPD
•
Comparison of measurements & simulation
• Conclusion
ToC - 2/17
Introduction:
•
Keeping buildings & rooms thermally comfortable is a key task of archictectural design
•
Traditional vernacular architecture adaption to the climate
•
Studies about different climate zones and thermal comfort in buildings there
Climate:
•
Malaysia: hot-humid tropical climate
Buildings:
•
Traditional: light weight wooden
structures (low thermal mass)
•
Modern: more and more brick
buildings
•
Natural ventilation during night
•
Massive use of A/C s…
Introduction - 3/17
Research Questions:
•
Indoor thermal comfort influenced by thermal insulation (reduction of night-time
radiant cooling)?
•
Thermal comfort in a 24h cycle?
•
Influence of thermal insulation on humidity?
Literature:
•
Givoni 2009 (hot & arid climate passive cooling):
passive cooling methods (night ventilation) work well in regions with diurnal
temperature swings of more than 8K
•
Kubota et al. 2009 (night-time ventilation in light-weight row houses in Malaysia):
non-insulated, cross-ventilation; Night ventilation can lower average daytime
temperatures by 0.5 – 2 K
•
Al-Hamoud 2003 (importance of thermal insulation in hot climates), varios other studies
on these topics
Literature /Research Questions- 4/17
Test-Cells:
•
Two per-se identical, free-standing test cells („A“ and
„B“))
•
3x3 m floor area, 3.6 m room height
•
110 mm brick/mortar, ceiling insulated with 50 mm EPS
Approach – Test-Cells - 5/17
Calibration:
•
Monitoring of A and B in terms to ensure identical thermal behavior (indoor
temperature, multiple days)
EPS/EIFS: Exterior Insulation Finishing System
•
Test Cell B was equipped with 50 mm of EPS and a thin brick cladding
Approach – Test-Cells - 6/17
Monitoring:
•
Thermal behavior of both test cells extensively monitored (10 days)
•
Six sensor positions inside the test cells (temperature, rel. hum.)
•
Additionally an outside-mounted weather station was used (ambient temperature,
outdoor rel. Hum., solar radiation, wind speed/wind direction)
Approach - Monitoring- 7/17
Ventilation regimes:
•
daytime (9 am – 7 pm): entrance door closed
•
Nighttime (7 pm – 9 am): door fully opened.
•
Air change rate was not measured, but could be considered to be similar
Dynamic thermal simulation:
•
Additionally: simulation of the test cells and their indoor environment (weather data
from site and via METEONORM), ventilation was assumed
Approach – Ventilation/Sim - 8/17
Results: Distribution of indoor temperatures
Results 9/17
Results: Temperatures indoor / outdoor in a 24h cycle (16th Dec. 2010)
Results 10/17
Results: Rel. Humidity indoor / outdoor in a 24h cycle (16th Dec. 2010)
Results 11/17
Results: PMV/PPD
Results 12/17
Results: Simulation / Measurements
Test-Cell A
Test-Cell B
EIFS
Results - 13/17
Results: Simulation / Measurements
Test-Cell A
Test-Cell B
EIFS
Results - 14/17
Conclusion:
• Temperature fluctuation higher in test cell A.
• Test Cell B features higher overall thermal comfort, given a 24 h
circle, stable
• Relative Humidity: affected through different temperatures.
• PMV / PPD: - gives an idea of the thermal comfort, but might not
be the ideal indicator (adaptive thermal comfort theory)
• Simulation is a good approximation of reality
• However: Slight overestimation of indoor temperatures in
Simulation (especially during daytime 0.5-2 K)
• Correlation between Measurements and Simulation are better at
non-insulated case.
Conclusion - 15/17
Future Work:
• Different layouts of buildings concerning openings, ventilation
regimes and thermal mass should be evaluated.
• Parametric modelling via simulation, (after fine-tuning the
calibration of the insulated test-cases)
Future - 16/17
Thank you for your attention!