Microclimate

Context:

The hourly weather data that are usually used as indicators of environmental loadings on building envelopes are often not sufficient. Studies show that accuracy of the heat-air-moisture (HAM) transfer simulation and calculated wind driven rain (WDR) amounts and intensities results are to a large extent determined by the time resolution of the meteorological input data (Blocken et al, Atmos. Environ. 2007, 41, 2335; Blocken and Carmeliet, J. Wind Eng. Industr. Aerodynamics, 2007, 95, 585). It is highly recommended that high-resolution data (e.g. 10-min data) be used for more accurate simulation results. This project will study the influence of microclimatic environmental loads that exists in urban downtown environment of Toronto on hygrothermal performance of various wood-frame exterior wall assemblies in real time, over at least 3 seasons, combining experimentation and simulation. The experimental measurements will be performed in a movable test-module, exposed to to real-life urban microclimate, defined by exterior air temperature, wind speed, solar exposure, surrounding buildings etc.
Simulations and experimentation will interact in this study in order to validate simulation tools by comparing its results with experimental measurements.

Significance:

 While many studies, especially in recent years, pointed out necessity of incorporating influence of microclimate on the hygrothermal performance of building envelope, at this point such study was not yet commenced. Researchers in Technical University of Denmark looked at the effect of microclimate in light of CFD modelling of moisture interaction between air and construction, but from the interior side of building envelope (Mortensen et al, J. of Bldg Phy, 30/4, 2007, 279). Therefore this study will be pioneering the attempt to:

1. investigate the effect of microclimate (i.e. urban heat island) and other environmental loadings immediate to the building on the hygrothermal performance of wood-frame building envelopes in order to quantify the difference in results between locally measured high-resolution data and averaged aiport hourly data;
   
2. Validation of simulation models (HAM-Tools): by comparing measured data with the results of simulations carried out in the same conditions as the experiment. Validated models can then be used to extrapolate experimental results and carry out the comprehensive parametric study that may be beyond pure experimentations.esolution data and averaged airport hourly data;
3. Validation of simualtion models by comparison with the results of other simulation softwares;