HVAC represents a large percentage of energy consumption within buildings and is applicable to essentially any inhabited interior space. On the large scale, HVAC is prevalent throughout the services sector—for example hospitals, malls, office space and institutional buildings.
HVAC efficiency can be improved through numerous strategies, such as building design, orientation and insulation.
This practice is focused on improving the control of HVAC systems to reduce energy consumption. This can be achieved through analysis of the existing control, demand and supply data, identifying opportunities to optimise the system using existing and new sensors and equipment.
An example is the use of zone controls to suit different rooms and areas. More careful control of HVAC outside of normal occupancy hours can also provide significant energy savings.
Sectors and common applications
- Commercial buildings
Energy saving across sectors is 19 PJ (2014 estimate).
|1. Energy saving and cost achievement|
|1.1 Energy saving||15/15|
|1.2 Cost effectiveness||6/10|
|2. Market contexts|
|2.1 Sector energy savings||6/10|
|2.2 % of industry $ gross added value||6/10|
|3. Originality and innovation|
|4.1 General applicability||5/5|
|4.2 Ease of implementation||4/5|
|4.3 Ability to integrate external resources||5/5|
|5.2 Social awareness||1.8/3|
Aldi Foods Ltd undertook a trial to link air conditioning plant operating hours to store operating hours and adjusting optimal plant start and stop timers. A simple controls modification ensured that after hours the heating mode was disabled and the supply fan only runs when room temperature calls for cooling.
The results indicated a saving of 25% of store mechanical-services energy consumption for a modest capital outlay, and the improvement was introduced into all stores. Implementation resulted in a saving of 26 500 GJ/pa, with an annual dollar value of $250 000. It also brought an annual reduction in GHG emissions of 7 350 tonnes, and a payback period of less than two years.
Wesfarmers Ltd trialled several HVAC initiatives. ‘Night setback’ was implemented, in which fans are turned off and the temperature band is widened to reduce HVAC requirements when stores are closed. Variable now provide adjustable speeds for main ventilation fans. AC timers adjust temperature according to the operational hours of individual areas/departments.
Harvey Norman Holdings Ltd uses economy cycles to reduce the amount of cooling required from compressors when conditions are suitable, i.e. outside temperature is less than internal temperatures. Savings of up to 25% can be achieved.
Other companies that have identified HVAC controls as sources of energy savings include:
For more information, see: