The New President Of Ingersoll Rand Climate Control - Thermo King

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Industry think tank and Thermo King determine the importance of return-air bulkheads: Optimum Refrigeration Performance, Improved Fuel Consumption, Minimum Environmental Impact “It was generally agreed that nothing currently on the market met all operator requirements.” 9 TTC Q2 April 2006 When Graham Eames joined Thermo King he looked at ways in which external resources could help operators improve the way their businesses were run, value customer service and reduce their costs. Many operators spent most of their time looking down and inwards, labouring to reduce margins and meet the greater customer demands. Having previously been part of a Think Tank on the truck side of the business, he proposed to a number of operators the introduction of a similar group for the UK industry. The result is a group of fourteen people made up of experienced, well-qualified Fleet Engineers and experienced, professional operational directors and managers. From the outset it was agreed that the Think Tank would meet three times a year to look upwards and outwards on behalf of operators, looking to utilise the combined experience of the team in finding ways of solving agreed technical or operational problems and, in doing so, take the industry forward. One of the first issues to be raised and dealt with by the team was that of return-air bulkheads. It was generally agreed that nothing currently on the market met all operator requirements and, in many cases, the bulkheads merely acted as an evaporator guard. The Optimum Return-Air Bulkhead During the course of 2005 the team put together a specification of what they believed to be the optimum return-air bulkhead, which would also be robust enough to act as an evaporator guard. They established that return-air bulkheads are important for optimum refrigeration performance, improved fuel consumption and minimum environmental impact. The purchase of a refrigerated box of any size has one prime objective: to create an environment of airflow and insulation to maintain a set temperature for a required duration and so preserve the integrity of temperature sensitive products carried in it. To achieve best possible performance from the majority of refrigeration units, it is important to ensure that the airflow around the trailer cargo area is optimised. Thermo King carried out tests that confirm one very effective way of doing this is with a correctly designed and installed returnair bulkhead. Thermo King also carried out tests, which concluded that improved air circulation inside the trailer means temperature management would be at its best and that a significant percentage of refrigeration capacity would be lost by the use of an inappropriate bulkhead. While the tests were carried out using a Thermo King fridge, the principal remains the same for all temperature-controlled units, regardless of manufacturer. All in the Specification The Think Tank went on to agree that unfortunately many bulkheads are not specified correctly, if at all. This can be detrimental to the unit performance, creating reduced refrigeration capacity along with increased fuel costs and therefore emissions. The group listed a number of key points that operators should consider: • Robustness - This is an important feature as is its integration into the trailer design. The operator should make his wishes on this clear to the body builder. • Pallet Stops - These should be designed into the trailer body at the base of the return-air bulkhead and be strong enough to withstand an impact from a pallet on a moving two ton forklift. They should be sited to provide air channels up to the bulkhead and cause no obstruction.
• Service Access - This should be a mandatory design feature and again be clearly requested by the operator. Refrigeration service technicians need to be able to have access to the fridge unit return-air area to gain access to components, for example the annual sensor calibration. Operators may also need to gain easy access for regular cleaning and other hygiene or HACCAP controls. • Air Flow - The bulkhead design should allow the majority of the return-air to be picked up from the floor area but should also have some side air channels at the lower half of the bulkhead. The design should not allow air to be sucked in from the top edge of the bulkhead or from any area in the top half of the bulkhead, as in these cases the air has not done its job and the 'short cycle' can create false and ineffective pull down times and poor temperature control The bulkhead does not need to be airtight as such, but should be integrated into the trailer body to ensure that the majority of the air does not leak. It should be as flush fitting as possible to avoid ingress of moisture and dirt. • Construction Material - This is a personal and practical choice of the operator. 12mm GRP faced plywood seems popular and works well but plastics and metal are equally suitable. Again robustness and hygiene would need to be considered. • Metal Gates - These can sometimes be found on trailers but are primarily intended to protect the evaporator area from impact damage. They are not effective temperature management devices. Bad Designs Can Restrict Airflow Logically, the Think Tank reasoned, anything that is meant to help with efficient air distribution in a confined space could also restrict that airflow if not designed properly. For example, two of the tests carried out, as shown in (Figure A and B) clearly indicated that if the top of the return-air bulkhead is open in any way, air can short cycle directly from the air outlet back to the evaporator without fulfilling its purpose of circulating the load to remove heat. The diagrams show how the air circulation velocity, at the bottom of the bulkhead, on route back to the evaporator differs when the top of the bulkhead is blocked off to prevent a short circuit. With that in mind it was noted that restricted airflow through small bulkhead channels or gaps would cause the air to flow slower than it should over the evaporator. This means the delivered air would be more refrigerated and, as such, lower than it should be. This can have a detrimental effect on fresh perishable products, with possible top freezing taking place. In addition it could cause the refrigeration unit microprocessor to believe the evaporator requires defrosting. In this case it would make the unit run frequently on high speed defrost and recovery, thereby effecting fuel economy and emissions. Further tests carried out on behalf of the Think Tank established that refrigeration units require a minimum of 52mm free air gap between the edge of the air return opening to the evaporator and the inner surface of the bulkhead. The channel below the evaporator must also be at least 52mm across the full width of the bulkhead. In practice most trailer designs will have a greater gap in this area, ideally about 95mm. It was also concluded that operators should specify some form of mesh to protect the entrances to the return air channels, which would avoid debris, and, in particular, bits of shrink-wrapping from pallets, getting sucked back to the evaporator and causing system problems or failure. Details of the Think Tank's findings are being circulated for discussion to UK body builders. Transport operators who would like further information on these findings or on the working of the Think Tank can call: +44 (0) 1326 560402 Q2 2006 APRIL “Restricted airflow through small bulkhead channels or gaps will cause the air to flow to slow.” 10 TTC Q2 April 2006
Page 1 and 2: Thermo King launches A Thermo King
Page 3 and 4: Q2 2006 APRIL New President for Ing
Page 5 and 6: Cargofresh Technologies and Transpo
Page 7: Reduce Costs, Improve Efficiency: T
Page 11 and 12: Thermo King’s world class team an

The New President Of Ingersoll Rand Climate Control - Thermo King

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