At the cutting edge of environmentally advanced cooling
| October 17, 2013
RAC Magazine's recent Cooling Industry Awards once again provided refrigeration and air conditioning suppliers the opportunity to demonstrate their environmentally advanced innovations.
We have realized over the years that each annual crop of entries provides a snapshot of best practices in the sector, largely focused on the U.K., but increasingly throughout Europe and the rest of the world. Furthermore, studying the range of award winners often reveals particular themes as the industry responds to the various challenges of legislation, energy and carbon reduction, and customer expectations.
Response to GWP restrictions
As Europe prepares for what is expected to be a major revision of its F-Gas legislation, the scope of innovation demonstrates that the cooling industry is able to scale up its response when necessary to meet ever-tighter restrictions on global warming potential (GWP), for instance.
If, as widely predicted, the new F-Gas rules effectively create a roadmap for exiting HFCs, this industry needs to be in a place where it is comfortable using natural refrigerants and other low-GWP alternatives. Many of the award winners showed practical ways to harness the attributes of naturals.
One such approach came from manufacturer Arctic Circle, whose Switch refrigeration pack uses hydrocarbon and CO2 in cascade. In warm weather, the CO2 runs in combination with a conventional high-stage hydrocarbon pack, but in colder weather, it "switches" to CO2 only — the high-side pack shuts down and the CO2 acts as a DX primary refrigerant. Where there is heat recovery installed, the system switches back to cascade operation.
One of the main benefits, the manufacturer says, is that the pack does not have to operate transcritically and doesn’t require CO2 pumps, making it simpler for engineers to maintain.
Another prevailing theme was refrigerant containment, which will be another vital element of the "post-F-gas landscape." If the industry cannot show itself to keep its refrigerants in the system, then it will lose further ground in the debate with policymakers over how quickly it should phase down HFCs. Of course, it has been noted by some observers that if the industry had been better at refrigerant containment in the first place, there would not have to be such a vociferous debate over replacing HFCs now.
“We shouldn't forget that global warming potential is only relevant if the gas is not kept in the system, so containment is vital — and remains just as vital for the natural alternatives, too,” said one of the judges Bob Arthur, consultant and former refrigeration technologist at retailer Marks and Spencer.
Perhaps the most revolutionary of the winners in this respect was the installation at Tesco Metro supermarket in Wolverhampton, U.K.. All of the store pipework is aluminium, rather than conventional copper, and the pipework is joined using a nonbrazed jointing method from manufacturer Reflok, based on patented self-sealing connectors.
It is claimed to be a world first to have a supermarket refrigeration installation in all-aluminium, offering the benefit of low installation weight — together with a jointing system that means no requirement for hot works — and carries the astonishing claim to be "guaranteed leak-free" if installed using Reflok's connectors and tools.
Another winner that addressed the leakage challenge sprung from the growing supermarket home-delivery sector. GAH (Refrigeration) designed its home-delivery refrigeration system to reduce leakage, but also to solve some of the other problems associated with refrigerated vehicles.
Its RD250e system uses a hermetically sealed scroll compressor, powered by an additional alternator driven directly from the vehicles crankshaft pulley, in place of conventional engine-driven compressors. Among the benefits of this are reduced pipework and hosing and a reduction in heat from the engine.
This is in addition to a simple LED-based diagnostic system and a direct link to the engineer's laptop, avoiding unnecessary intervention in the system in case of maintenance. But perhaps the most impressive part of the system is its use of the refrigeration system's main standby to automatically pump down and pressure test the system at times when there is no cooling demand.
A third theme also addressed the direct emissions challenge. Glycol and water-based secondary refrigeration techniques are becoming increasingly popular with supermarkets, firstly because it keeps the initial refrigerant charge low, and secondly because it reduces the amount of refrigerant that has to be piped around the store — reducing the risk of leakage from less accessible pipework and keeping the gases out of public areas.
Energy reduction through heat recovery
The fourth prevailing theme was energy reduction through heat recovery techniques. This is viewed by many as the next great frontier for both supermarkets and process cooling applications, since they both have significant waste heat from their refrigerated systems which can be diverted towards the heating needs.
One application combined both the secondary cooling and the heat recovery, to provide energy-efficient beer cooling for bars. Irish company REL Cooling Services has worked with manufacturer Lancer to produce a beer-cooling system that uses a glycol mixture in place of the ice bank systems often used.
The glycol/water mixture, chilled to minus-4 degrees C, is pumped to the beer taps, cold rooms and remote bottle coolers. REL's claims to energy efficiency are impressive — 50-65 percent savings over the conventional methods. A further benefit is the ability to serve beer at 0 degrees C without the need for additional under-counter cooling.
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