From office thermostats to planetary impact: a Cambridge quest for greener cooling

The Marks & Clerk Cambridge office normally enjoys a reasonably harmonious atmosphere. However, the office air conditioning unit can prove to be a source of occasional tension; my efforts to recreate the fresher climate of my northern homeland in the comparatively tropical setting of East Anglia are not always appreciated. 

But, it seems I am not alone in my pursuit of cool¹. According to the International Energy Agency, cooling – whether for air conditioning or other refrigeration applications – represents around 10% of global electricity demand. This figure speaks both to an (already) high level of demand for cooling solutions, and to the underlying energy-intensiveness of existing refrigeration systems. 

Conventional cooling methods rely on driving phase changes in fluid refrigerants. The thermodynamic changes associated with these gas-liquid conversions are responsible for the generated cooling effect, which requires a high energy input. Beyond the environmental cost of energy generation, materials commonly used as refrigerants (such as HFC’s²) can have greenhouse effects thousands of times more potent than that of carbon dioxide, making a significant contribution to anthropogenic climate change when they leak to the atmosphere.

A vicious cycle therefore presents itself: as global temperatures rise, demand for cooling increases, which can itself be a driver of further warming. Although I personally can no doubt cope with an extra few degrees on the office thermostat, a recent report suggests that “rising global heat is now killing one person a minute around the world”, demonstrating that ‘space cooling’ is increasingly becoming a necessity rather than a luxury. 

Industry also has its own growing cooling requirements. As discussed by my colleague Simon Portman earlier in our series, AI data centres have a large appetite for energy, up to 40% of which is used for cooling. Consumer goods companies must also grapple with the need to store and transport products at low temperatures, a key hurdle on their path to net-zero.

Needing to strike a balance between rising demand and negative environmental consequences, how can we be more sustainable in our craving for cooling? Two Cambridge companies have worked to answer this question. 

Technology developed by Barocal replaces conventional fluid refrigerants with the barocaloric solid materials from which the company takes its name. Barocaloric solids undergo changes in structure under the application of pressure. The desired cooling effect is obtained via the temperature changes derived from these molecular rearrangements. 

Camfridge - like Barocal, a spin-out from the University of Cambridge - have pioneered a further alternative to the use of refrigerant gases, likewise avoiding their fugitive emissions. Camfridge’s focus is on magnetic cooling, employing iron alloys which exhibit temperature changes on application of a magnetic field. Their technology was recently featured by Cambridge Professor Hannah Fry on BBC’s The Secret Genius of Modern Life, which is worth a watch for a demonstration of the technology. The materials used in Camfridge’s devices also benefit from being recyclable. 

For both companies, initial research and development focused on the caloric materials on which their technologies rely. The commercial success of their products will be driven by the improvements in efficiency offered by devices incorporating the materials, representing an economically-viable replacement of existing solutions and advantageously reducing energy consumption. Barocal also stress the “inexpensive, plentiful, and safe” nature of the solids they use, while Camfridge recently demonstrated the integration of their technology into a commercial cooler. 

Barocal and Camfridge have therefore pursued different green solutions to the same underlying problems, taking novel approaches to cooling which are nonetheless underpinned by the same thermodynamic principles as century-old refrigeration techniques. Both companies have had their innovations recognised by various awards and have patent strategies in place to protect their technologies, standing them in good stead as they continue to commercialise their innovations. 

I’m looking forward to seeing how their work develops: perhaps sometime soon their products will give me greener justification for nudging down the temperature in our office. In the meantime, to read about other (less literally) cool Cambridge innovations, please do check the rest of the articles in our Green Growth series.

Reference:
¹See an impassioned American argument for a Cooler Britannia
²Though not as damaging to ozone as their notorious CFC forebears.