About 40 per cent of the energy consumed in buildings is dedicated to providing indoor thermal comfort through heating, ventilation, and air conditioning (HVAC) systems. Technology advancement of these systems is therefore crucial for achieving decarbonisation goals.
Air conditioning (AC) is currently the fastest-growing end-use in buildings and its demand is projected to increase further in the following decades due to population growth, income-level rise, urban development, and climate change.
Australia’s climatic extremes, particularly the scorching heat experienced during summers, have made air conditioning an essential feature in residential and commercial buildings.
This, along with goals to increase the energy efficiency of buildings, has led to a rising demand for AC products that can lower energy consumption and building emissions.
Another significant observation in this market is the rising incorporation of technology to elevate both the quality and efficiency of products. In this regard, technologies such as artificial intelligence, machine learning, and blockchain are being harnessed to create innovative products.
BOOSTING ENERGY EFFICIENCY
Global actions to reduce the impact of cooling on climate change and the environment are mainly focused on improvements to refrigerants and increasing the energy efficiency of ACs.
However, unlike refrigerant-related actions associated with ozone-depleting substances which are governed by global agreements, energy efficiency policies for air conditioners vary across countries and regions.
For instance, in the United States, residential air conditioners are required to meet the minimum seasonal energy efficiency ratio (SEER) values of no less than 14. By 2023, this value will be raised to 15 SEER in the southern regions of the country, where cooling loads are higher.
Meanwhile, the European Union has implemented energy labels in ACs and introduced the concept of ‘ecodesign’, which includes minimum energy efficiency requirements, maximum sound levels, and detailed product information to regulate the use of environmentally-conscious devices.
Globally however, the decarbonisation of space cooling is progressing slowly; which was the basis of a recent study into the total emissions burden of ACs, published in Energy and Buildings last year.
The six researchers said through a comprehensive approach like the Life Cycle Assessment (LCA), a detailed quantification of the environmental impacts and their corresponding consequence on human health and other potential damages can be determined.
The researchers noted that while several studies have already targeted the LCA of AC systems including the embodied CO2, Life Cycle Cost (LCC), and the LCA of different refrigerants, a clear overview of those studies’ methodologies, assumptions, and results is still lacking.
However, by studying existing literature, the researchers could conclude that vapour compression heat pumps/chillers connected to the grid generally exhibited the highest global warming potential (GWP) impacts compared to renewable- powered AC systems.
They also found that solar sorption chillers generally presented the lowest GWP impact ranges. However, their environmental performance was not advantageous when the system’s lifespan was short (10 years), and the electricity of the context was already clean.
AC systems powered by PV panels also exhibited lower GWP impacts than conventional systems and only overpassed them when the PV field was designed to partially cover the thermal load of the space.
