02 - Retrofitting the Judge Business School:

Thermal Comfort University of Cambridge

Architectural Engineering Project

October - November 2022

This architectural engineering project focused on improving thermal comfort and reducing energy consumption in the Judge Business School, Cambridge. Thorough analysis of the school, alongside various stakeholder interviews, identified thermal control as a critical issue for the retrofit. Given the significance of thermal comfort in educational settings, the project aimed to align with ASHRAE standards and recommendations from organizations like the World Health Organisation and CIBSE, which advocates a maximum temperature of 24 degrees Celsius in working conditions.

The group report explored various categories, including shading devices, natural ventilation, heating systems, and building envelope insulation. Working as a group posed various challenges, such as coordinating diverse ideas and schedules, but it ultimately provided valuable learning outcomes in collaboration, problem-solving, and project management.

Individually, I worked on the proposal for shading devices on the façade, contributing to the broader project’s objectives to create a comfortable and adaptable environment; reduce glare; enhance concentration; and align with carbon-efficient principles. Throughout the design process, collaboration with the team was - essential to ensuring a cohesive group proposal.

The shading devices aimed to block direct sunlight during the summer while allowing sunlight penetration in the winter. Solar analysis and shading calculations were used to determine the most efficient shading strategy. The building’s grade II* listed status posed a unique challenge, emphasizing the need for interventions that aligned with the building’s fabric with a low embodied carbon footprint.

The research explored various shading strategies, resulting in two distinct shading panel proposals: BIPV Panels and Timber Panels. Following embodied carbon estimations, the more cost-efficient and environmentally mindful option was the Timber Panel strategy. While BIPV panels may eventually become carbon-positive, the analysis suggested that roof solar panels alone were sufficient for the building’s energy needs. Timber panels offered a longer life span, potentially double that of BIPV panels. Their discreet, natural aesthetic integration and sustainable design aligned with the building’s character. Considering these factors, the timber panels emerged as the optimal proposal.

Examination Result: 75

Iteration 1: BIPV Shading Panels

BIPV panels integrated into the shading system aim to harness solar energy on the south-facing side of the shading fins. These panels will convert solar energy into electricity, simultaneously blocking direct sunlight penetration. Additional PV panels on the roof will contribute to a renewable energy source.

This system allowed for customization options to match the façade’s playful colour scheme. Efficiency calculations indicated a high average efficiency of 17.02%, making it a commercially viable PV option. Another advantage was its potential to not only provide a sustainable energy source and reducing energy bills, but even generate profit by feeding unused energy back into the grid.

The disadvantages of this option included a high initial cost and a high embodied carbon due to the steel structural supports needed. The lack of precedents for BIPV shading devices contributed to the uncertainty on - outcomes. The initial investment would only be economical with sufficient energy absorption, and with effectiveness of the system hinging on consistent solar energy, this increased uncertainty.

Iteration 2: Pivot Timber Shading Panels

Solar incident radiation analysis using a Rhino model indicated that the roof received substantially higher incident radiation than the shading devices. This challenged the cost-effectiveness of installing BIPV shading devices, which would increase retrofit costs and construction-related carbon emissions.

An alternative strategy proposed the use of sustainably sourced pine wood for the shading devices, with solar cells limited to the roof, The adjustable shading system permitted angle changes for extended shading in summer and optimized solar penetration during winter. The material choice for this option resulted in much lower embodied carbon, as well as increased creative freedom in the shape of the panels. The reduced weight of the panels when using timber also minimized the material required for the load-bearing structures. Aesthetically, the natural finish offered a more discreet intervention, in compliance with the building’s Grade II* listed status.

The main concern with timber was its susceptibility to weather damage and colour changes, which would necessitate regular re-treatment with waterproof sealants, potentially increasing the carbon footprint across its lifespan. In addition to this, adding the Dynamic shading system would incur a higher initial cost than its static alternative.