11 wins in the RIBA Regional Awards
Cranmer Road, King's College, University of Cambridge
Cranmer Road is an ultra-low-energy, all-electric, Passivhaus student accommodation development for King's College Cambridge. With its low embodied carbon structure and low operational carbon emissions, Cranmer Road is the model for a new generation of projects aspiring to achieve net zero carbon.
Key information
Architect
Allies and Morrison
Client
King's College, University of Cambridge
Value
£9.6M
Year of Completion
2020
Sector
Services
Challenge
Fifty-nine graduate student bedrooms are provided across two new accommodation buildings each of differing modern character, designed to sit comfortably alongside the neighbouring arts and crafts villas. With its low embodied carbon structure and low operational carbon emissions, Cranmer Road is an exemplar student housing project that showcases many of the approaches to sustainable and low-energy design that are essential for current and future projects aspiring to achieve net zero carbon.
Working alongside Allies and Morrison Architects, we provided MEP, Passivhaus, and Acoustics for this project. As Passivhaus consultants, we supported the design team and contractor from early stage design through delivery on site. This included helping evaluate the benefits and implications of Passivhaus so the client could decide whether to adopt the standard and supporting the design team to develop a low-energy, buildable design, including facilitating workshops, carrying out modelling using the Passivhaus Planning Package (PHPP), and thermal bridging calculations.
We also worked with the contractor through the site phase to help them realise the design, and inform specialist subcontractor design development, liaised with the Passivhaus Certifier throughout the project and provided acoustic input relating to the sound insulation from the CLT construction and for planning, as well as noise surveys.
Our project team
Total of 7 people
Design strategy
The buildings use electricity as their sole energy source, which aligns with the ongoing decarbonisation of the electricity grid. Mechanical systems are decentralised, with point of use space heating and instantaneous domestic hot water generation, to limit distribution losses. Waste water heat recovery and low flow showers limit the energy required for hot water, and mechanical ventilation with heat recovery (MVHR) is used to limit heat loss and ensure good air quality year-round.
The summer comfort strategy has a combination of automatic bypass of the heat exchanger on the mechanical ventilation units, and openable windows. The design uses simple, standard components in systems that were easy to commission and should be simple to maintain.
The buildings achieved airtightness results three to four times better than the Passivhaus limit, more than 50 times better than building regulations allow. Measured peak heating demand has been 8 W/m², lower than the Passivhaus target of 10 W/m².
20%
lower peak heating demand than Passivhaus target
3x
better airtightness performance than Passivhaus limit
Video
Ensuring occupant comfort
We provided a simple building user guide for every student, so they could understand the background of the building and how to interact with it to achieve comfort in a low-energy way.
Reviewing the operational energy consumption allowed a sense check to understand if the services and systems were operating as intended and target areas for improvement, with the analysis helping to demonstrate that the building generally aligned with the modelling.
Carrying out an occupant survey allowed both energy use and occupant feedback to be brought together to ensure that very low energy consumption wasn’t being achieved to the detriment of occupant satisfaction and comfort.
Quote
"The College has a history of high-quality architecture, and the Cranmer Road student accommodation lives up to these standards. Using timber as the primary structure helped to limit the scheme's embodied carbon, while operational energy is kept low through Passivhaus. Electricity is the sole fuel source, which works well with the ongoing decarbonisation of the UK electricity grid."
Gwilym Still
MEng PhD CEng MIMechE
Director, Passivhaus
Partner
Gallery
Total of 5 images
© Nick Guttridge
© Nick Guttridge
© Nick Guttridge
© Nick Guttridge
© Nick Guttridge
Awards highlights
| 2023 | CIBSE Building Performance Awards | Project of the Year (Non-Domestic) |
|---|---|---|
| 2021 | Passivhaus Trust Awards | Large Projects - People's Vote |
| 2021 | Cambridge Design & Construction Awards | Engineering and Sustainability Project of the Year |
