This study presents an investigation into efficiency and operation of an under-floor
HVAC system at an office complex in London against a number of KPIs. Energy consumption
of different system components was monitored for seven months together with time
log graphs of room temperature and carbon dioxide levels at each floor.
Thermal comfort and ventilation control of the system was assessed against performance
criteria specified in ASHRAE standards. Energy consumption of the system was compared
to a conventional over-head VAV system and an air-conditioning system at an office
complex in Singapore. User experience was assessed by analyzing questionnaires completed
by building occupants. Whole Life-Cycle Costing of under-floor HVAC system was compared
to VAV, VRF, FCU and CC systems available on the market today.
Carbon footprint analysis showed that annual carbon footprint of WMProtek under-floor
HVAC system is 197 tonnes of CO2; with 0.54tonnes/person. Typical AC system has
an annual carbon footprint of 1.125 tonnes/person, which is 52% higher. Annual savings
in carbon emissions of the under-floor system are equivalent to 211 trees planted
or 132 cars taken off British roads.
From above the two main conclusions can be drawn:
- WMProtek under-floor HVAC system is good at achieving the objectives it was designed
- The under-floor AC system is more flexible, energy efficient and cheaper than a
conventional overhead VAV system.
- Therefore, based on the results of this study, it can be concluded that the WMProtek
under-floor HVAC system is likely to perform better than an over-head VAV system.
New Hall College
Department of Engineering, University of Cambridge, UK