The federal government has published the results of bench tests undertaken on refrigeration and air conditioning (RAC) equipment to determine the benefits of routine maintenance.
The Department of Climate Change, Energy, the Environment and Water engaged recognised RAC equipment testing experts to find out if additional power is used when common faults are applied to selected equipment.
The study involved testing four pieces of RAC equipment commonly used in Australian homes and small businesses.
The tests were conducted by SuperCool Asia Pty Ltd and the CSIRO.
SuperCool tested a refrigeration display cabinet and a remote walk-in cool room and the CSIRO tested a single non-ducted split system and a light commercial roof top package.
Each piece of equipment was run for a baseline performance read before the common faults were introduced. The faults tested were blocked condenser, blocked evaporator, refrigerant undercharge and overcharge and contaminated refrigerant.
As part of the project the government was also able to acquire testing data undertaken by Cresstec Pty Ltd on a piece of air conditioning equipment at the CSIRO NATA accredited facility.
This testing was undertaken at T1, T2 and T3 temperature zones, for similar fault tests.
Display cabinet
The two door vertical refrigerated display cabinet was set up in a controlled environment, without a heat load.
The tests revealed that numerous faults had substantive impacts on energy use, with the impact of 40 per cent condenser blockage having the greatest negative impact on system performance, where the energy consumption increased by 15.7 per cent.
The tests provided insights into the amount of energy consumed for individual faults, and a summary of how much worse it can get if multiple faults coincide. When several faults or maintenance issues co-exist in a system, it is likely that energy use would increase substantially (approx. 36 per cent in the test undertaken).
Based on the results, it was concluded that regularly scheduled system maintenance could significantly increase efficiency and reduce energy use. In many cases, this is a relatively simple maintenance procedure, such as coil cleaning.
Cool room
The walk-in cool room results revealed a significant impact on energy use when faults were introduced including a blocked condenser, a blocked evaporator, refrigerant under and overcharge, and refrigerant contamination.
The impact of contaminated refrigerant had the greatest negative impact on system performance, with the energy consumption increasing by 70 per cent.
Air conditioning
CSIRO tested the cooling capacity, heating capacity, electrical power consumption and operating efficiency of a 7kW reverse cycle, non-ducted variable speed split system air conditioner, and a 16kW reverse cycle fixed speed package air conditioner. To simulate blocked airflows, perforated metal sheet was installed over the air inlets of the indoor and outdoor units.
Testing under these fault conditions resulted in minor (zero to six per cent) reductions in unit capacity and performance.
The testing found substantial improvements in system efficiencies can be attained by ensuring the refrigerant charge is correct.
The results are available at:
Bench testing results of refrigeration and air conditioning equipment - DCCEEW