Smart control

A systems approach will lead to taking greater care with control and communication technology that can play a role in energy efficiency optimisation.

In some cases, existing control system settings can be optimised. The key point here is to question historical settings and to re-assess the actual needs of the system. A few examples:

• Data centre cooling systems are often still programmed based on the maximum air inlet temperature of old servers which are no longer active in the room. The new servers currently active sustain air inlet temperatures at several degrees higher, giving rise to substantial energy savings by merely changing the cooling system set point [CEN-CENELEC 2016].
• In compressed air systems, sub-optimal set points that do not take the actual circumstances into account are common. For example, the compressor outlet temperature might be set higher than necessary, or the air dryers keep the dew point to a lower figure than actually required, resulting in unnecessary energy consumption [ECI 2011].
• In HVAC systems, it is a common failure to set heating and cooling set-points too close to each other. “[…] if heating and cooling set-points are too close, such that air conditioning cools a space while it is simultaneously being heated, users will not necessarily be aware of what is happening and are unlikely to complain unless thermal comfort is also affected. This all-too-common situation illustrates just one of the many implementation and operational failures that can occur and remain undetected with building energy controls, no matter what their degree of sophistication.” [WSE 2014, p.2]

In other cases, adding intelligence and communications technology to components can be of great help in improving the actual energy performance, detecting faults and correcting sub-optimal user behaviour. For example:

• In a non-residential building, window blinds can be operated automatically based on solar radiation measurements, and this shade system can also be connected to the lighting control system in the room. Such automatic controls avoid energy losses consequent to users omitting to adjust the settings when needed.
• In an extensive industrial compressed air network, installing a system master control is recommended which, if configured correctly, can select the most energy efficient combination of compressors for the required output at any given moment. According to [Ecofys 2017], installing basic technical building systems with payback times of less than two years can save the EU about 27 Mtoe of primary energy per year, corresponding to 61 Mt of CO2. Examples of such systems are thermostatic valves on heating radiators, and automatic hydronic balancing to keep constant pressure in HVAC fluid circuits.