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Exploring frontiers, expanding opportunities: the future of rac

The rac industry’s role in shaping the future of the environment in which we live should not be underestimated. And, as Professor Graeme Maidment, and Dr Issa Chaer of London South Bank University propose can take a lead with improvements in technologies and applications

Currently much of the rac industry is focused on surviving the economic downturn. However, our industry may fare better than others because refrigeration is vital to modern life. Although refrigeration is an integral part of almost every person’s life it is essential that refrigeration technologies continue to evolve and develop.

At present, rac equipment consumes around 16 per cent of all UK electricity and is 50 per cent of an average supermarket’s energy demand. Therefore the rac industry must continue to innovate and develop to deliver solutions suitable for the future.

The interrelated issues of global warming and security of provision of our energy supply are going to become more acute in the future at a time when demand for rac will be growing and temperature control requirements becoming increasingly challenging.

Figure 1 shows the potential change in temperature in the UK by 2080. This will have a significant impact on our building, industrial processes and cooling applications. 

An illustration of what this might mean for just one sector of our building stock is shown in Figure 2. To-date temperatures in a typical London flat rarely rise above 28 deg C.

However in the future this is predicted to rise continually so that in 2050, 15 per cent of the time temperatures will exceed 28 deg C. This has real implications for the rac industry. It will be increasingly challenging to provide sufficient cooling effectively and economically.

Meeting targets

Over recent years we have seen a raft of legalisation which is influencing how we design, operate and maintain our rac equipment.

Much of this legislation is aimed at reducing environmental impact and while this may represent additional up-front costs, it is also going to support improvements in efficiency performance and refrigerant containment. In turn these will help to sell more efficient equipment into an increasingly tight financial market.

National targets for reducing carbon emissions are not going to disappear because of the recession, in fact if anything there could be increasing pressure to reduce carbon emissions even further.

The recent EU, “Towards a comprehensive climate change agreement in Copenhagen” discussion paper suggested that developed countries should reduce their emissions by 30 per cent below 1990 levels by 2020 and 50 per cent below 1990 levels by 2050.

One of the suggested ways of achieving these reductions was further controls on HFCs and increased research into the development of low GWP and HFC-free alternatives.

Controls on use of HFCs however miss the point that in many cases the majority of a refrigeration system’s global warming impact is due to indirect emissions from energy use. Support for research into alternatives is to be welcomed – provided that those refrigerants can deliver efficiency improvements.

Scope for change

There is much that can be done now to minimise the need for cooling and ensuring that design, operation and maintenance take into account the operational and carbon cost as well as capital.

This will require education of purchasers, the widescale adoption of industry best practice and the development of systems with long life spans and good part load efficiency.

The scope for improving efficiency is large. An example of this is shown in Figure 3, which shows a comparison of Japanese air conditioners. Efficiency of the Japanese products are typically about twice those in the European market.

There is also much scope for the wider adoption of new more efficient components and systems. For example, advanced materials and components can enable significant improvements in heat transfer resulting in COP improvements.

Micro-channels offer the opportunity to increase heat transfer coefficients to 10 times that of large bore tubes. We are now seeing implementation of CCHP (combined cooling heat and power) and high efficiency trans-critical CO2 cycles.

Heat pumps provide the opportunity to expand refrigeration technology into the heating market. Many of these technologies present opportunities to achieve further savings if they can be integrated to utilise their heating and cooling potential to the full. This may require the sharing of heat and cooling between different buildings or even different end-users.

Renewable energy is a high profile and rapidly emerging technology which is attracting financial incentives.

The integration of renewable energy technologies within rac can offer valuable synergies. For instance, cold storage can provide an energy store or battery for intermittent wind power and solar-powered air conditioning can provide cooling when the sun shines.

At the same time novel cycles still at the development stage, such as magnetic and electro-caloric refrigeration, could offer the potential to improve system efficiency still further. No doubt there are many additional technologies that the rac sector could make use of which are still at research or concept state and that will help us to achieve even greater savings in the future.

Some may argue that the present time is not the right time to be considering investing in sustainability or carbon efficiency. However, the development of low carbon technologies have been cited by both the US and UK governments as providing one of the mechanisms for escaping a recession.

Knowledge bank

SIRAC, the network for sustainable innovation in refrigeration and air conditioning, is trying to help accelerate the adoption of new technologies into the market place.

By bringing together researchers in Universities and industry with real problems to solve we are building up knowledge, putting new teams together and creating a forum for the development of new ideas. 

If you are interested in contributing to this process please join us at our next free network meeting at Warwick University on 13 May 2009  where, amongst other things, we will be being looking at a sustainable plan for the future of refrigeration and air conditioning.