Over the last 25 years the refrigeration landscape has changed significantly, “will it change as much in the next 25 years?” is a question I was asked recently.
Since the early 2000s, there has been a growing realisation that we should be moving to low greenhouse gas (GHG) refrigerants and in response ‘Natural’ refrigerants, such as hydrocarbons for small integral (plug-in) systems and R744 (carbon dioxide) for large remote refrigeration commercial systems, have been widely adopted. Larger industrial systems already used R717 (ammonia) and this has not changed. There has also been a proliferation of lower Global Warming Potential (GWP) synthetic alternatives, many of which fall into a new A2L (i.e. mildly flammable) category. In Europe the move to natural refrigerants is being driven by the f-gas regulations, which are rapidly driving the market towards a GWP of less than 150 and will reduce to zero the quantity of hydrofluorocarbons allowed to be placed in the EU from 2050 onwards.
Refrigeration systems over the last 25 years have predominantly been vapour compression based1 and this core technology has not changed from the traditional direct expansion and overfeed systems. Where there have been changes is in some of the components. This has been mainly driven by requirements for better energy efficiency, due largely to legislation and the increasing costs for energy, which have made some new technologies cost efficient for end users to apply. For example, technologies such as electronically commutated motors (EMCs) and light emitting diodes (LED) for lighting were rapidly deployed around the turn of the century and are now almost universally applied across the refrigeration sector. More recently, variable speed drives and linear compressors for smaller compressors, electric expansion valves and display cabinet doors in commercial refrigeration, and heat reclamation systems, have been shown to be economic.
Looking forward, technologies on the cusp of being widely adopted include the use of digital twins and AI systems, as well as high temperature heat pumps. The industry is being encouraged to rapidly decarbonise, which means an increased use of electricity generated from renewables and the need to enhance the current electrical grid. This creates new challenges for refrigeration systems, including how to integrate them into the grid and provide storage and flexibility for alignment with electricity generation. Appropriate training and skills are also required to install, support and maintain these systems.
Replacing the incumbent technology?
Alternatives to vapour compression have been under development for many years, but most are unlikely to be commercially available in the short term. Many need specialist manufacturing facilities and use scarce materials. Therefore, on the journey to 2050 it is difficult to visualise a widespread replacement of vapour compression, particularly as it is such a deeply entrenched technology, available universally, and well understood. A few non vapour compressor systems have been developed with potential uses in niche applications, for example Air cycle2 and Peltier3. Passive systems4 should, of course, always be considered for air conditioning and space cooling if suitable. However, we should bear in mind that some use water and this is likely to become a critical resource in many locations in the future.
Air cycle systems have undergone development and are now commercially available in some countries, including in Japan for low temperature food cold stores used with products such as tuna (which is kept at low temperature for quality reasons). It also has some potential for storage of low temperature (-80°C) pharmaceuticals. Systems such as Peltier have uses for spot cooling or in applications where vapour compression cannot be used. Heat driven cycles have uses where there is sufficient high grade waste heat available that cannot be usefully utilised elsewhere. Cryogens5 also have some niche opportunities if low temperature or ultra-fast cooling is required.
Leapfrogging to a more sustainable future
Whilst these recent technology developments have been taking place in the Global North, refrigeration deployments in counties of the Global South have started to develop at a rapid pace. Countries in Africa, for example, have in response to increasing levels of economic growth begun to install cold chains for food and pharmaceuticals. Developing nations often have significant potential for the application of renewable energy and the adoption of best-in-class technologies from mature developed counties, essentially ‘leapfrogging’ the transition stages of the move to low GWP refrigerants and energy efficiency.
Although it is tempting to simply copy what has already been done in the Global North, this approach is unlikely to always be the right or optimal solution and we should therefore take care not to just sell, or ‘dump’, technologies into the markets of the Global South where they may not be truly suitable. In this regard, cold chains in Africa have different requirements: electricity grids are often not well developed; some refrigeration equipment is not widely available; and skills to maintain and operate systems often need to be developed. Taking the best learning from mature developed countries makes sense, but it needs to be applied in a way that provides real benefits for users in developing countries.
Renewable energy generation has large scale potential in Africa. However, to fully utilise the available resources the ability to store energy is essential. Thermal energy storage is becoming increasingly critical in all markets as the need to shift energy use and integrate with renewable energy grows. In contrast to electrical batteries, this alternative approach stores energy thermally when it is cheap or freely available and then releases it for use at times when energy is expensive or unavailable. It is ideal for Africa where there are often abundant solar, wind, wave and geothermal resources.
Understanding and meeting the need
As cold chains develop, an essential task is to consider the needs of end users and to help them understand how to create robust and profitable businesses when applying refrigeration technologies. Systems need to be well designed, low cost to operate, and reliable. They should seamlessly integrate between the sectors of the cold chain and provide real benefits for communities. In parallel, policymakers need to also support the development of cold chains and understand that they are critical infrastructure and an essential component of economic growth.
It is important in all markets, but especially those where new systems are rapidly being deployed, to understand how climate change will affect operation of refrigeration systems in the future. Africa is warming at a faster rate than the global average, yet the turnover of refrigeration plant may only occur every 20-50 years so existing plant will have to cope with increased higher temperatures and may fail unless adapted. With new installations there is a real opportunity to design with climate change in mind, thereby ensuring that systems are future-proofed and not locked into sub-optimal technologies or designs. Design standards should encompass climate change. An initiative in the UK is starting to develop a Code of Practice for refrigeration systems to be correctly designed to cope with future changes to the climate. Ultimately this needs to be extrapolated out to other countries, such as those in Africa, to ensure all refrigeration systems are fit for the future.
The journey to 2050 will certainly provide exciting opportunities in refrigeration. One of the initiatives at the Africa Centre of Excellent in Sustainable Cooling and Cold Chain (ACES) is to encourage more people to become involved in the wide range of careers that are available within the sector. We need well trained, appropriately skilled, and enthusiastic people to help us move this vision forward over the next 25 years.