Common issues identifi ed by continuous monitoring include leaks in compressors, over-sizing and blocked fi lters Ian Knight


domain on the measured energy consumption of HVAC systems, says Dr Ian Knight, iSERV project coordinator and reader at Cardiff University. ‘The old adage “you can’t manage what you can’t measure” is very apt for HVAC systems,’ says Knight. ‘There is an absence of publicly available information derived from large-scale datasets on the detail of energy consumption of HVAC systems in buildings.’


HARMONAC revealed that inspections


did not always identify under-performing systems. Through monitoring the project was able to identify and analyse 141 different energy conservation opportunities (ECOs), but it concluded that many of them would be missed by inspection. The sub-hourly data from the 42 sites revealed that inspections only identifi ed 37% of the measures that


60 CIBSE Journal January 2013


could have been taken to improve effi ciency in those systems. ‘Inspections record a point in time – you


see little of the control issues and you can’t see whether the system is consuming more energy than it should or is not running properly,’ says Knight. HVAC systems also tend to be serviced shortly before inspections, says Knight, meaning that systems that would benefi t from the inspectors’ knowledge – often those that are not regularly serviced or monitored – are often missing the opportunity to improve their operating and maintenance practices. Common issues identifi ed by continuous monitoring includes leaks in compressors, over-sizing and blocked fi lters. It also fi nds solvable control issues, which are not expensive or diffi cult to remedy, such as


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