Session: 12-10-01: Heat Transfer in Natural and Build Environments

Paper Number: 198616

An Experimental Investigation of the Impact of Multiple Trees on External Flow and Convective Heat Transfer of a Model House 

To combat global warming and meet climate action goals, it is necessary not only to increase the share of clean energy but also to reduce overall energy consumption. Buildings account for approximately 30% of global energy demand, with 70% of this energy used by residential buildings. In cold climates, most of this energy is used for space and water heating. In Canada, water and space heating account for about 79% of energy use in the residential sector and about 60% in the commercial and institutional sector. Most of this energy for heating comes from fossil fuels. Energy models are an important part of predicting and designing efficient buildings. Wind can significantly affect a building’s external energy exchange primarily through convection. Trees are common features in neighborhoods, often located in proximity to buildings for shade or even specifically implemented as windbreaks. Although the interaction between wind and trees is physically complex, their effect on nearby buildings is not well understood. Hence, there is a need for studies investigating the underlying mechanisms of wind interactions with trees and nearby houses. The impact of trees on external building energy exchange has not been well parameterized in current building energy models.  
 
The present study is focused on the experimental investigation of the external airflow through multiple trees and its impact on the heating of a model house in a wind tunnel. A simple model house was constructed from acrylic and fitted with internal heaters, recirculating fans, and active control, such that the internal temperature could be held at a fixed differential from the measured ambient temperature. Thirty thermocouples were placed at strategic locations along the walls and roof of the house, both internally and externally, to measure the external heat loss through the walls. Additional thermocouples measured the ambient temperature within the house and the bulk temperature of the incoming flow. The transient flow patterns were characterized from above using planar particle image velocimetry (PIV). PIV enables near-instantaneous, full-field characterization with high spatial resolution. This study builds upon previous work using a single model tree, in this case, applying common configurations of multiple trees in a residential setting. Tests were performed at two wind speeds and three temperature differences from ambient. The impact of the trees on heat transfer from the model house under these tested conditions was analyzed in the context of the transient flow fields captured using PIV and compared with the case when no trees were present. 

Presenting Author: Kyle Teather Western University

Presenting Author Biography: Kyle Teather earned his PhD in Mechanical and Materials Engineering in 2023 from Western University in London, Canada, and is currently a Postdoctoral Researcher there. His research interests include renewable energy, latent heat thermal energy storage, and convective heat transfer.

Authors:

Kyle Teather Western University
Kamran Siddiqui Western University