Reduce Waste “ Passive insulation beats mechanical intervention ,” said Coetzee . For example , on building constructions , he advises keeping façades shorter in the west and east directions , improving roof insulation and insulating wall cavities depending on the climatic zone the building is being constructed in .
“ Furthermore , external window shading devices significantly impact solar loads . Horizontal shading on north façades can reduce the solar load by ± 25 % in some instances ,” he said . Angled vertical shading should be applied to east and westfacing windows .
When mechanical intervention is needed , air-to-air heat exchangers and an economy cycle is effective when increasing ventilation rates . He added that electrical heating must be avoided as far as possible . Air conditioning units should have set points not too low in summer and not too high in winter as per SANS 204 Recommendation .
SANS EXTRACT : 4.6.7.1.2 Thermostatic controls for comfort should be capable of adjusting the set point temperature of the space they serve to between 20 º C and 24 º C in summer .
Awareness Coetzee said it is also important to create a culture of awareness . “ Display screens showing the building ’ s energy consumption can be shown so that technical staff can report outliers if it exceeds the recommended consumption . The technical information should also be translated to more relatable concepts for non-technical staff to ensure a wider adoption of sustainability principles .”
Furthermore , he also emphasised educating the end user . “ Everyone needs to take ownership for the sake of the environment . For example , air conditioning units should be on set points as recommended by SANS , while turning the unit off should not affect fresh air . Users ’ expectations must also be managed to ensure the system is operating within the design envelope .
“ Systems should be switched off when it is not used , whether it is manual , via occupancy sensors that include a timer or infrared sensing , or via BMS , which offers additional functionality at a premium ,” he said . “ Nothing is more energy efficient than a system that is switched off .”
Maintenance and Optimisation He added that problematic areas should be monitored , identified and remedial work actioned , while well-performing areas should also be pinpointed to set new benchmarks and to attempt to duplicate operations . E . g ., if two similar rooms have varying power consumption an investigation is required to determine the cause of the difference .
CARL COETZEE Director at Lombard Consulting Engineers ( LCE )
“ Leaks and deteriorating insulation should be identified and be maintained , equipment must be in good working condition , and filters and coils must be clean . To optimise , ambient conditions must be made use of . For instance , run heat pumps when it is hot outside for making domestic hot water , use economy and flush cycles , and use floating set points on chilled water ( CHW ) systems ,” he said .
According to Coetzee , there is no simple answer to becoming sustainable but rather a series of small interventions . “ Increasing the air changes per hour ( ACH ) can be achieved and kept in line with the EPC values if the building and services design is optimised ,” he said . “ While certain buildings are not yet included , it may be in the future , so it is better to start designing for this now .”
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