Purdown View, UWE Bristol. Image, Tom Sparey

The heating energy load at a flagship purpose-built student accommodation (PBSA) development in Bristol has been reduced through the use of an innovative building control system.

The University of the West of England (UWE) commissioned Prefect Controls to install its Irus system at Purdown View – its newest PBSA site.

Purdown View is one of the largest Passivhaus-certified developments of its kind in the world and also the first in the university sector in the UK.

Built in the heart of the UWE Frenchay Campus, this energy-saving project is key to UWE achieving its 2030 net-zero sustainability target.

Constructed in three blocks of up to six storeys, the development comprises studio flats and clusters of four, six, and eight bedrooms with en-suite or shared pod shower rooms, offering, in total, 900 beds.

The buildings will yield a 54% reduction in running costs and carbon emissions compared with a typical ‘good practice’ building.

Prefect Controls’ involvement with this project follows the successful retrofit of Irus across the existing 2,000-plus rooms at the Bristol site, where it has been saving more than 800,000kWh a year.

Irus is a centrally-controlled Building energy Management System (BeMS) which currently controls space and water heating in 70,000 rooms at more than 130 sites across the UK.

It works on the basis that the Setback mode maintains a comfortable room temperature while occupants are present. But, when the room is unoccupied or windows are opened, heat input is reduced.

Students can increase their room’s temperature using Boost mode, but the profiles that are set via the internet portal will return the room to the Setback mode after a pre-determined time elapses.

This ensures the thermostat cannot be turned to ‘max’ and left there all term.

Temperature and time parameters are infinitely changeable. Typical examples are Setback 18°C and Boost range of 20°C-24°C for 45 minutes.

And Frost/Off mode engages when rooms are unoccupied for longer periods.

Heat input is turned off until the room temperature falls below 10°C-12°C. This avoids damp and damage caused by moisture or frost.

And this three-mode operation means energy is never used unnecessarily.

All settings are adjusted on the dedicated, secure internet portal. And during the commissioning process, different profiles are loaded.

Those granted access to the system can change parameters on a room-by-room basis to ensure individual student comfort, without ever needing to visit the room.

However, at the end of term, the ‘Reset-all’ feature enables every room to be brought back to the same profile – ensuring complete compliance with the site’s heating policy.

Individual room controllers send data to and from the portal using the existing electrical wiring, a technique known as Mains Borne Signalling (MBS). This is cost effective and negates the expense and disruption of installing additional data cabling.