KEEP CALM AND INCREASE EFFICIENCY With increasing focus on environmental performance, energy efficiency is an
important, ongoing issue for manufacturers, users and contractors of commercial refrigeration systems. Here, Stuart Corr, Techno-Commercial Director of leading
refrigerant manufacturer and supplier Mexichem, discusses the four factors that impact on the energy efficiency of today’s refrigeration equipment.
Approximately 75-85% of the carbon footprint of a refrigeration system comes from its energy consumption. The percentage is even higher if the equipment uses reduced GWP refrigerants and if it is well- maintained, to reduce leakages and keep losses to a minimum.
Energy efficiency is a multidimensional problem but as a rule for refrigeration systems, the first step is to make sure you minimise the requirements for cooling, making best use of insulation and other steps that contribute to minimising heat loading. Integrating air and heat flow can result in significant improvements for air conditioning and refrigeration systems. Just as poor home insulation results in an up to 30% increase in the size and consumption of the boiler, commercial environments experience significant losses unless they minimise their requirements for heating and cooling.
Having minimised heat loading, identify the optimum performance for the appliance and finally, ensure you recover and use any waste heat or cool air.
THE RIGHT REFRIGERANT The cap and phase down of HFCs under the EU F-Gas Regulations makes it important to carefully consider your existing refrigerant and your options for moving to reduced GWP alternatives.
This is particularly important for those systems using higher GWP refrigerants such as R-404A, which are likely to be in increasingly short supply as regulations tighten, meaning retrofit options should be considered. R-407A is a proven, energy efficient alternative for R-404A – affording the twin benefits of a reduction in refrigerant GWP and
30 | REFRIGERATION
the potential to make a significant reduction in energy consumption.
R-407A is compatible with the major system components used for R-404A, including compressors, lubricants, pipework, heat exchangers and valves. The ease with which it can be retrofitted is established in the field, whilst its potential for improving energy efficiency has been well documented and quantified in both laboratory and field implementation studies.
CORRECT COMMISSIONING For refrigeration applications to be efficient, users should ensure the system is properly commissioned and correctly sized for the anticipated loads, avoiding the temptation to under or over-size the system. Traditionally, over-specification was a common industry practice, but improved management of leakage and refrigerant loss and better heat-load management over the last few years helps to provide greater load certainty and hence more robust sizing targets.
Whilst in many cases an off-the-shelf system will be ideally suited and bring potential economy-of-scale benefits, the end-user should also be aware that a custom-designed system may in some circumstances provide a more tailored and efficient solution. Refrigeration system designers can advise on the most appropriate type of refrigerant, control valves, compressor technology, capacity control measures, type of condensing and control system design and strategies. Temperature, load and evaporator layout can be unique to each project, which means that compressors, condensers, evaporators and valves
should be selected specifically for each application.
PREVENTATIVE MAINTENANCE Once the system is up and running, correct maintenance is the best ally against system inefficiency and breakdown. Working with a well- informed contractor can help end users save costs on maintenance and the logistical problems that go with system failure.
Only trained technicians can carry out work on equipment containing fluorinated (F) gases. To prevent leaks and losses and to ensure the equipment is running at optimum efficiency, facilities managers should ensure maintenance checks take place every three months or at least twice a year. The EU F Gas Regulations explain in more detail how often maintenance is required, depending on the system specifications and refrigerant used.
Regular preventative maintenance is also important to ensure general system health and to keep the system working at its optimum, allowing users to reduce power consumption, extend the life of the equipment and its critical components and finally, avoid costly downtime.
The best way to stay on top of preventative maintenance is to create a checklist that is specific to your system. This could include anything from clearing the condenser, checking the condition of door seals, monitoring and adjusting the thermostat and temperature, checking the refrigerant level, inspecting door hinges and door closers etc. Even the easy wins, such as replacing old door gaskets, have a positive impact, especially when we’re talking about a large system.
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