Cold Link Africa July/August 2019 - Page 32

FEATURE INCORPORATING COLD CHAIN Locally, there seems to be a growing interest in trans-critical CO 2 installations, according to La Grange. Clients are putting large trans-critical installations in place of what might have been ammonia installations traditionally. In such cases, the capital outlay of the trans- critical CO 2 systems compare favourably to a more costly ammonia installations. CO 2 trans-critical installations are also favoured in terms of cost over an ammonia/CO 2 cascade systems in some cases. Having one refrigerant on site does have its advantages. The cost of CO 2 Staff should always wear the correct personal protective equipment (PPE) in cold store environments. SPEED, EFFICIENCY AND SAFETY Speed and efficiency of the loading and unloading process should also be taken into consideration. Hydraulically operated dock levellers operate much faster and more reliably than their air- powered counterparts. With the standard, integrated stop-valve in the cylinders the hydraulic units also offer superior safety which prevents the unit from falling down in case the truck accidentally drives/rolls away during the loading and unloading 32 process. Besides less maintenance, fewer parts underneath the hydraulic dock leveller also aids in keeping hygiene to a maximum as debris and dirt are easily visible and accessible to clean. A LOOK AT TRENDS Being environmentally friendly is one of the biggest trends currently, explains Ford. “Environmentally aware products such as CO 2 are slowly becoming more cost effective to use too.” trans-critical systems is likely to always be higher than any HFC or HC solutions due to the higher operating pressures. Globally, the use of hydrocarbons like R290 and R600a is growing dramatically, according to La Grange. “The skills required to design and build systems using hydrocarbons are very similar to the skills needed for HFC systems. The HC systems of course being less costly than CO 2 .” On the industrial side, a lot of R&D has gone into alternatives to modulate the capacity that screw compressors offer on the larger systems, says La Grange. Most compressor manufacturers have invested heavily into this. “It is generally a stable industry and change is a gradual process,” says Van der Merwe. But he has noticed a move towards installing more electronics for plant monitoring, data logging, and off site access to plant operational information. “The available solutions are becoming more affordable while offering similar levels of information and storage.” In addition, the industry is becoming more cost conscious and this is putting pressure on quoting for a good technical solution with redundancy and providing some form of back-up for equipment failure versus equipment selections that are marginal and possibly undersized, says Van der Merwe. “It should be borne in mind that if an air-conditioning system fails to perform then the people may complain that is warm but it will still be more comfortable than the outside ambient conditions,” says Van der Merwe. “If a cold store installation fails to perform as required, then the client’s operational requirements may be compromised and product quality and shelf life could be negatively affected.” Executive summary? Look at future- proofing in terms of refrigerants as well. You don’t want to put in a system run on refrigerant gas that will be phased out soon. If you’re going to build a cold store, do it right, or it’s going to cost the client a lot of money in the long run. CLA COLD LINK AFRICA • July/August 2019