We are pleased to announce the second round of case study selections for ATMOsphere America 2014, which will feature several parallel technology case study sessions. The 3rd annual conference will take place from 18 – 19 June in San Francisco, California.
Embraco has been present for many years as one of the most active companies in promoting hermetic compressors for use with hydrocarbons worldwide. The positive 2011 EPA SNAP conclusion opened an opportunity for the US household and light commercial refrigeration applications to reduce their environmental impact. Today, highly polluting substances are used in ultralow biomedical cascade applications. Embraco’s case study will show how to convert present -86°C applications into low environmental impacts products by using hydrocarbons in both system stages. Embraco’s full compressor product line for ultralow cascade applications for the American market will be presented.
Low charge ammonia – the natural replacement for R22 by Derek Hamilton, Star Refrigeration (Azane)
The case study will start with an update about the U.S. R22 phase-out and the effects this is having on the industry. It will present lessons learned in Europe from the R22 phase-out process and how these can be applied in the U.S., as well as options for end users after R22 and considerations that must be taken into account when moving away from R22 in large commercial or light industrial applications. The case study will also discuss the benefits of using air cooled as opposed to evaporative condensers. Finally, it will highlight a case study of a dairy facility in Puerto Rico, where the end user is investing in an air cooled ammonia package to replace an ageing R22 system.
Efficient and practical container refrigeration applications using CO2 by James Taeckens, Carrier
As the shipping industry becomes more focused on making further improvements to reduce the global warming potential (GWP) of refrigerated container shipping, much attention has been given to CO2 emissions, both direct and indirect. In anticipation of this growing concern, last October Carrier announced the commercial launch of the world’s first natural refrigerant container unit, the NaturaLINETM, which uses CO2 refrigerant. For container shipping, CO2 (R-744) is the only refrigerant that offers a GWP of one, avoids harmful direct emissions, has zero ozone- depletion potential and is classified as non-toxic. In addition, the NaturaLINE unit is designed to achieve industry leading energy efficiency equal to Carrier’s PrimeLINE® unit. The units have successfully operated over a full range of ambient temperature settings and conditions, maintaining frozen and perishable set points -35° C (-31° F) to 30° C (86° F), on routes crossing the Atlantic and Pacific oceans, on trips ranging from 4- to 28-days. To demonstrate the success of the NaturaLINE sea trials, Carrier will provide a case study on the details of the successfully completed trials. Overall performance characteristics, such as energy and CO2 emissions savings will be discussed along with comments on the commercial phase and launch of the NaturaLINE product.
Application of subcritical CO2 evaporative condensers and evaporative transcritical CO2 gas coolers by Klaas Visser, KAV Consulting
In the case of ammonia condensing, it is possible to operate an evaporative condenser at an air entry wet bulb temperature to condensing temperature approach of 6 K. This means that a properly designed evaporative condenser for subcritical CO2 condensing at 30°C maximum, i.e. 1.1 K below the critical point, may be applied for a wet bulb design condition of 24°C or lower. Canada, large parts of the USA and China, and most of Australia below the tropic of Capricorn have climates suitable for the application of evaporative condensers to subcritical CO2 condensing. This case study will highlight the benefits of applying evaporative condensing techniques for the condensation of subcritical CO2. These benefits include lower design pressures, lower energy consumption, lower running and operating costs. Hot gas defrosting would also become a standard feature of subcritical CO2 refrigeration plant operations.
Disadvantages would be the need for a water supply, water consumption and water treatment, and control of a minimum condensing temperature as currently mandated by some compressor manufacturers. Control strategies to handle transcritical conditions are examined and it is found that evaporative transcritical gas coolers will also be of great benefit in virtually all tropical areas with ambient Wet Bulb temperatures up to 29° C.