Rayyan Badrul, Hannah Dilger, Lucas Dubelt, Saskia Raiff and Zack Weiss
- Community Partner: UBC Campus + Community Planning (facilitated by SEEDS Sustainability Program)
- Degree:
- Bachelor of Applied Science
- Program:
- Campus: Vancouver
Our project
Dense urban areas are hot. Buildings and pavement absorb and store more solar energy than natural surfaces, and they lack the cooling impact of vegetation and transpiration. This leads to the urban heat island effect, which results in higher ambient temperatures than are found less-dense areas, as well as increased air pollution and greater energy demand for air conditioning.
On the UBC campus, heat-mapping consistently shows higher temperatures in highly developed zones compared to less developed or green areas.
We were asked to develop strategies to reduce the urban heat island effect for Exeter Hall, a residential development of a high rise and city homes under construction in UBC’s Wesbrook Village. This included reviewing the current design for Exeter Hall, developed based on an older green building rating system for multi-unit residence at UBC, to see if it meets the updated Residential Environmental Assessment Program (REAP 4.0) performance criteria. All new residential buildings on UBC campus must align with REAP 4.0, which includes an optional credit for mitigating urban heat.
Our design solution
We focused our design modification strategies in four key areas: the roof, walls, pavement and landscape. For each category, we developed a range of potential interventions that we then evaluated using a weighted decision matrix against the criteria that were most important to our client, including feasibility, cost, heat-reduction potential, aesthetics and transferability to other UBC buildings.
Our final design package includes green roofs on the townhouses to increase transpiration, reflective paint on the exterior walls to reduce stored heat, permeable pavement on sidewalks, and a bioswale to increase vegetation and manage runoff.
Using the Surface Urban Energy and Water Balance Scheme (SUEWS), a model that simulates the urban radiation, energy and water balances, we modelled the impact of these designs on our energy balance through changes in area coverage ratio.
We decided to put our focus on reducing the sensible heat flux that contributes to warming air circulation, while increasing latent heat flux to promote more evaporation cooling effects.
Over the study area, our analysis indicates an 8,493 W reduction in mean sensible heat flow and a 4,470 W increment of mean latent heat flow. These changes in heat fluxes reduce surface and ambient air temperature, which are the two main indicators of urban heat island mitigation. If implemented, our proposed design solutions would also lead to a 37% reduction in embodied carbon compared to the baseline, in alignment with UBC's Climate Action Plan 2030.
The technical challenges we faced
This project required us to work across multiple domains, from building science and hydrology to landscape architecture and materials engineering, and translate this knowledge into a unified design. Early on, we generated multiple design options across our four categories, which left us with 20 possible interventions to assess.
To make justifiable decisions, we had to learn the design principles, codes and performance standards for each domain and then build a clear decision‑making framework.
Working with our client, we refined our evaluation criteria to meet their priorities of maximizing heat-reduction performance, ensuring feasibility and creating solutions that could be replicated across campus. This helped us narrow our focus.
What’s next for this project
Exeter Hall is already in the construction stage, so the intent of this project is not implementation within this development. Rather, the goal was to develop a transferable design framework and set of recommendations that can inform future projects and similar developments. Our report and design package will be distributed through SEEDS and made available to inform future design efforts. Findings from this project will also be used to inform future updates to REAP, and other relevant Green Building policy.
We also developed a retrofit package, which includes green roof additions, bioswales and vegetation enhancements, that can be applied to existing buildings.
