3. Control/set point
The most energy-efficient air conditioning systems installed in any application can be rendered energy inefficient if not controlled in the correct manner. Most of today’s control options can greatly increase the efficiency of an air-conditioning system. Control of operation times and set-point temperatures are the most basic and fundamental of control functions that will enhance system efficiency.
However, depending upon size and type of air conditioning system installed, more sophisticated control systems should be considered so that additional functions such as ‘night set back’, centralised set-point control and occupation detection facilities can be utilised to improve operation. It is always worth asking users how they expect to use the space that is to be air conditioned. Also consider options available on air conditioning systems, such as Energy Saving and Economy modes.
Always be aware of the competition by users to either have the maximum heating temperature set point compared to the lowest cooling set point. Centralised control should be considered for this instance as constant adjustment of the set point will only result in erratic operation of the system and a reduced level of efficiency, not to mention the most uncomfortable conditioned space.
Finally, avoid the possibility of independent systems ‘fighting’ against each other whilst in different operating modes, ie one system heating whilst another is cooling in the same space.
4. Refrigerant charge
Paying attention to refrigerant charge is important for any air-conditioning system. Undercharging will result in the starvation of refrigerant within the system, in turn reducing the ability of the refrigerant to absorb the required amount of energy to satisfy the heating or cooling demand of the conditioned space. Operation times will subsequently increase and defrost cycles will become more frequent creating higher risk of system failure and reduced capacity and space temperature control.
If a system is undercharged, always check for leaks within the pipe work and equipment and repair or replace as necessary before re-charging. Also be aware that some refrigeration systems may also be subject to routine leakage testing requirements under the F-gas regulation (EC Regulation No. 842/2006 on Certain Fluorinated Greenhouse Gases).
Frequently, these issues stem from poorly planned installation in the first place that make inspection and maintenance difficult or even impossible. If the filter or coils cannot be inspected or cleaned, the system’s efficiency will be dramatically reduced as the airflow across the coils becomes restricted. Over time this will result in costly repairs to the condenser as the compressor will inevitably fail.