Fume cupboards are used intensively in some of the research activities in the University. The Department of Chemistry alone has around 386 units.
These localised fume extraction systems are fitted into scientific and medical laboratories to protect individuals from harmful substances that could otherwise be inhaled. The existing airflow control system is aimed at controlling the airflow into and out of laboratories. However, they are also energy-intensive pieces of equipment with significant associated carbon emissions.
Effective use of ‘variable air volume’ fume cupboards uses less energy because the air removed from the building is lessened when the sash is lowered. Leaving sashes open or open more widely than necessary means that air from the lab is expelled from the building unnecessarily. One analogy is that this is like heating your house, opening the windows, and running a fan to blow the heated air out.
There are around 350 variable air volume fume cupboards at the University, with around 300 in the Chemistry department. For every inch the University’s average sash height goes down, we could save up to £50,000 per year.
Behaviour change: Shut the Sash campaign
A Cambridge variable air volume fume cupboard with the sash 60cm open running 24h / day costs £1420 per year to run, whereas a closed cupboard (5cm opening) costs £491.
Given fume cupboards need to be open for academic work, achieving this saving is unfeasible, but given some cupboards are left open all night and when researchers are away from their cupboard of work, closing the cupboards before leaving work could have a highly significant impact on the University’s energy consumption.
The Shut the Sash campaign targets savings available through behaviour change of staff and students when not using the fume cupboards.
Technological intervention: zone presence sensors
The Department of Chemistry are in the process of trialing new control devices to optimise the performance of existing fume cupboard ventilation.
The trial involves the installation of Phoenix Control Zone Presence Sensors (ZPS) on existing fume hoods. These will optimise the air-flow through fume cupboards and minimise the amount of air-conditioned laboratory air that is exhausted out of the building.
How do they work?
The ZPS detects the presence of personnel in front of a fume hood. When an operator is present, the ZPS signals the fume hood system into a standard, higher extract airflow mode.
When operators are absent, the ZPS signals the fume hood system into a standby, lower extract airflow mode.
It is expected that this new air flow management system could significantly reduce Chemistry’s energy consumption relating to these areas.