Rouhollahi, M., Whaley, D., Byrne, J. and Boland, J., 2022. Potential residential tree arrangement to optimise dwelling energy efficiency. Energy and Buildings, p.111962.
Energy–efficient dwellings promote substantial urban energy conservation. Residential tree allocation, as an Urban Heat Island (UHI) mitigation strategy, stimulates climate responsivity, lowers Air Conditioner (AC) usage and heat distribution. This paper evaluates dwellings’ response to residential tree planting parameters to assess the building–surround relationship. These parameters include tree type (evergreen or deciduous), volume (1–3 trees), Tree–Building distance (3 m or 5 m) in each cardinal and inter–cardinal azimuth. These planting configurations highlight dominant Australian urban planning policy and green open space restrictions.
This study quantifies tree planting configuration models, utilising both typical and extreme weather data and a bi–seasonal approach, to arrive at an Optimal Residential Tree arrangement (ORTa). The simulation process tailors local weather data to assess tree impact upon the diurnal and nocturnal microclimate.
The ORTa dependence upon orientation ensures correct deep soil levels and viable private backyard volume. The result demonstrates a high probability that deciduous trees save energy bi–seasonally.
Across all aspects and weather conditions, ORTa allows for an evergreen tree addition to boost energy conservation without detrimental annual or bi–seasonal effects on building thermal response. Annual weather data indicates two deciduous trees are optimal. These trees would be located east or west at 3 m Tree–Building distance (T-B distance), north at 5 m T-B distance or south at 3 m minimum with the maximum depending upon neighbour’s northerly aspect.
In typical weather conditions, two deciduous tree arrangements lead to maximum 40% heating energy
conservation from any potential ORTa in east, west or north. In addition, it provides 15% east or west cooling energy saving and 7% north. In extreme weather conditions, two tree arrangements provide 25% thermal heating conservation, in any aspect. During heatwaves easterly deciduous tree planting is optimal
(18% energy conservation), followed by westerly (7%) and northerly (1%).
This research recommends five ranked optimal tree arrangements depending on residential parcel deep soil availabilities. This optimisation result encourages decision–makers to appreciate residential green space and reanalyse future urban canopy cover target measurements.