Cool Solutions: Is it Possible to Beat the Heat Sustainably?

As climate change intensifies, reliance on air conditioning (AC) is rising, with dire consequences for the environment. In Ontario, about 83% of households now use AC to cope with increasing heatwaves, but this comfort comes at a significant ecological cost. AC units and refrigeration systems represent approximately 10% of global greenhouse gas emissions, a figure projected to increase, especially as Canada warms twice as fast as the global average. The shift in energy usage patterns may lead new buildings to consume more energy for cooling than for heating, as noted by David MacMillan from Toronto’s Environment and Climate Division.

This situation creates a feedback loop: rising temperatures prompt increased AC use, which further fuels global warming. Consequently, there is a pressing need for innovative cooling solutions. Traditional cooling systems are inefficient; the International Energy Agency reveals that many consumer AC units perform at less than half the efficiency of the best models. Moreover, electricity demand soars during hot days. In regions reliant on older power sources, such as Ontario, this surge can activate more polluting power plants. For instance, during heatwaves, the Waigaoqiao power station in Shanghai can burn vast amounts of coal to meet this demand.

To address these challenges, new technologies are being explored. Enwave’s deep lake water cooling system, for example, harnesses chilled water from Lake Ontario to cool around 100 buildings, cutting electricity demand significantly and offering a more efficient alternative to traditional cooling plants. Nevertheless, this solution is limited primarily to downtown areas, prompting the need for other options like heat pumps. These devices facilitate heating and cooling by transferring heat, and an innovative project at Toronto Western Hospital aims to utilize thermal energy from wastewater for its HVAC needs, illustrating a creative method to tap into an often-overlooked energy source.

Humidity further complicates energy efficiency. Excess moisture in the air makes it more uncomfortable and energy-intensive to cool spaces. While traditional AC and dehumidifiers address humidity through energy-consuming processes, Evercloak suggests the use of graphene oxide to develop membranes that can extract moisture from the air without significant energy expenditure, potentially halving AC energy requirements.

Despite technological advances, architectural historians like Daniel Barber emphasize the need for fundamental changes in urban design and lifestyles. Pre-AC architectural techniques, such as passive ventilation and shading, should be revisited to reduce dependency on mechanical cooling. Barber advocates for a cultural shift in work habits and expectations about temperature management. For example, adjusting work hours to cooler periods of the day could enhance comfort while lowering energy needs.

As the reliance on AC persists, the quest for effective cooling solutions becomes critical. Balancing technology’s role with thoughtful urban planning and changing societal behaviors will be essential to mitigate the environmental impact of cooling systems and accommodate rising temperatures.