Ever since the EU has committed to cut greenhouse gas emissions by 20%, food retailers have been under enormous pressure to reduce their carbon footprint. Refrigeration is part of the solution, as it accounts for some 50% of the energy consumption in a typical store. A new report by the British environmental consultants SKM Enviros evaluates different refrigeration solutions.
Refrigeration systems in supermarkets have been in the line of fire for quite a while. Not because of their energy consumption, but because of their direct f-gas emissions due to leakages. However, looking only at the refrigerant without taking into account the energy consumption of the system and other parameters such as climate can be quite misleading and detrimental to the environment. Indeed, energy consumption typically represents between 60 and 80% of the climate impact of a refrigeration system over its lifetime. A study conducted by the British environmental consultants SKM Enviros and commissioned by the industry expert organization EPEE sheds light on the relative importance of the choice of refrigerant for the global climate impact of a refrigeration system and thus on the persistent myth that using one particular refrigerant is the universal remedy for supermarket applications.
Reproduced with kind permission from EPEE.
The Carbon Trust, The Institute of Refrigeration and the British Refrigeration Association have worked together to produce a ‘Refrigeration Road Map’ for reducing carbon emissions in retail refrigeration applications. The Refrigeration Road Map has been developed to assist supermarkets, contractors and equipment manufacturers to identify the technologies most likely to reduce CO2 emissions in supermarket refrigeration systems.
This could include actions such as basic improvements in leakage monitoring, new approaches to design and installation, the introduction of alternative refrigerants, or the creation of zero carbon stores. The Refrigeration Road Map provides information on the technologies that are most likely to save carbon emissions, and prioritises them in terms of carbon saving potential, relative cost and limits to commercial maturity.
The technologies included in the Refrigeration Road Map have been divided into three sub-groups:
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Reproduced from Refrigeration Road Map CTG02, with kind permission from the Carbon Trust.
A well-known British consultant to the refrigeration industry claims that R404A should be eliminated from refrigeration applications, because it does not achieve the best energy efficiency in many applications and, with a GWP of 3,7841 is the highest of all the commonly used refrigerants, compared with R134a (GWP 1,300) and other HFC based blends.
R404A has become one of the most widely used refrigerants, after having been introduced in the 1990s as a replacement for CFC refrigerants such as CFC-12 and CFC-502, and more recently as a replacement for HCFC-22. In the supermarket sector it has become the dominant refrigerant across Europe for both chilled and frozen food refrigeration. It is also used widely in other commercial systems, for industrial refrigeration and for cold storage.
The relatively poor energy efficiency of R404A systems leads to extra running costs and also extra CO2 emissions from the energy use. Alternative refrigerant blends could give energy savings of between 7 and 12 percent in many applications.
The GWP of R404A is 3,784, while two alternative blends, R407A and R407F have respectively a GWP of 1,990 and 1,705. Both blends contain R-32, R-125 and R-134a, R407A with 20/40/40 weight-% and R407F with 30/30/40 weight-%.
The consultant proposes not to use R404A in any new systems, a practical and cost effective strategy as the other blends suit all R404A applications, will deliver an improved efficiency and have a significantly better climate impact.
For a new plant, the refrigerant choice falls into 3 main groups:
For an existing refrigeration plant, the majority of supermarket chill systems can be retrofitted with a medium GWP refrigerant such as R407A or R407F. In addition to using a lower GWP fluid, a carefully planned retrofit programme will have 3 other benefits:
Combining these benefits can reduce the direct climate impact of the R404A system by as much as 75 percent and reduce the indirect electricity related CO2 emissions by a further 10 to 15 percent.
As most supermarket refrigeration systems have a life of 15 to 20 years, it is important to have an investment programme that combines the best refrigeration strategies for both new and existing plants.
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