Cold Link Africa July/August 2019 - Page 27

FEATURE INCORPORATING COLD CHAIN Consider installing mobile racking to ensure that the size of the cold store is minimised for the pallet holding capacity with the subsequent reduced running costs associated with a smaller cold store. • • • • • • Updated and correct qualifications are a must. Ensure that the correct design is done for what is required to be output of plant. No shortcuts. Make sure you account for more than enough capacity. Don’t compromise on insulation. Understand the mandate. Always maintain a clear space between the rack frames and the loaded pallets as well as between the pallets themselves. owner must do their homework on the contractor’s track record and their client base – not simply consider the price for the installation.” “Energy savings vs price is a major challenge,” Ford says as well. People generally want the most efficient plant but have a very tight budget, and the more expensive units are cheaper to run and have a high return on investment. “The cheaper system may not offer long-term running and energy savings. Clients want a Rolls Royce for the price of a Citi Golf.” La Grange adds that often good solutions aren’t considered because it cannot be done in the short time frame allocated. The electrical supply available on the planned site is becoming more relevant too, according to La Grange. Expanding the electrical distribution network requires long-term planning in most cases. Existing industrial sites often have a very big supply connection, without the need to upgrade to a very costly new distribution network. In some cases customers pay for transformer upgrades at huge cost before considering a more energy efficient system. “Good empirical evidence can help many a customer not make that mistake. Electrical upgrades are very costly,” he says, and can cause major delays. Another challenge is designing a system that can match the part load conditions closely as well as the full load conditions required, says La Grange, “the goal being to match the cooling demand closely with what the system can supply”. The variables are the cooling load as well as the ambient conditions where the facility would be built. Ambient conditions influence the heat load calculations and the system’s condensing conditions. Should the selected solution use an evaporative condenser, the relative Humidity RH and Wet WB across the seasons needs to be factored in thoroughly, he advises. Ford adds that it can be tricky satisfying customer needs and incorporating those needs into a practical design. “Sometimes the customer wants one thing but the product being stored has other requirements.” But the challenges aren’t just the cold store’s refrigeration equipment – but also the operation, explains Merrick Smith of Pro Active Refrigeration. “Typical cold storage rooms are high and workers are required to work at height with lifting equipment and relevant safety gear.” “The greatest challenge is making sure that the fruit is on temperature and all procedures are being followed, and the safety of all people on site,” explains These are Smith’s tips: • Make sure that piping and equipment are kept dry and clean when being stored while waiting for installation. • Ensure that pipe insulation is glued and joined correctly. • Ensure that free air movement is allowed for around all insulated piping. • Ensure piping is installed so that effective oil return to the plant occurs. It’s never quite as easy as it looks – every project has its challenge. The budget definitely has a big influence on much of the decision-making, so that is often a big challenge, explains La Grange. Van der Merwe agrees. “Low pricing combined with marginal equipment selections and non-compliance with current legislation will always offer a favourable price to the owner. This will often result in a system not achieving the desired operating conditions.” The owner cannot see the final product, they can only see a price on a quotation and must make a decision without understanding the effect of their decisions. “The CHALLENGES With the dock leveller outside the building which is closed by a properly insulated and sealed sectional door, the amount of air exchange that takes place during loading is limited. COLD LINK AFRICA • July/August 2019 27