Case studies by Danfoss and Colmac Coil, Azane, CIMCO Refrigeration, and CTA Architects Engineers have been selected for ATMOsphere America 2015. These presentations will cover a variety of different topics including a new ammonia/CO2 based system now available in the U.S., the installation of Azane’s low charge, air-cooled ammonia packages at a national frozen food chain, an ammonia DX low charge system, as well as a NH3/CO2 cascade refrigeration syst
In addition to the following case studies that will be presented at ATMOsphere America 2015 (25 & 26 June in Atlanta, Georgia), the programme will also feature a dedicated low charge ammonia panel where some of the pioneers in this field will present the latest technology updates and discuss market forecasts in industrial applications, but also in commercial and HVAC sectors.
Ammonia DX low charge system proves sustainability by Terry Chapp, Danfoss and Jeremy Olberding, Colmac Coil Manufacturing
The case study presents a project designed with a low temperature (below 0°F) direct expansion (DX) ammonia refrigeration system at Joliet Cold Storage Warehouse, a 130,000-square-foot warehouse and logistics centre in Illinois. Opened in June 2014, the owner was looking for a cost-effective, sustainable refrigeration solution that would reduce construction costs and operate below OSHA’s 10,000 lbs PSM threshold.
The presentation will include a comparison of the two initial refrigeration design suggestions: a pump recirculated liquid (PRL) ammonia system and a DX ammonia system; and explain how the chosen DX solution was able to provide $100,000 in capital savings and use 35% less ammonia; thereby, allowing the owner to operate below the PSM threshold. It will also show how this solution is scalable for mainstream deployment.
Low charge ammonia – the natural choice for frozen food distribution by Derek Hamilton, Azane
When a national frozen food chain was designing a new distribution centre, their specification called for a safe, natural and energy efficient refrigeration solution. The facility, incorporating a -17.7°C freezer space and 1.6°F dock, was being constructed as part of an ongoing project to modernise the firm’s distribution network. The client wanted to benefit from the efficiency and reliability of an ammonia system, while minimising the quantity of ammonia used.
After considering various refrigeration options, the new facility was designed using Azane’s low charge, air cooled ammonia packages. The installation was completed in the summer of 2014 and has delighted the client by delivering low running costs and hassle-free operation. The case study will look at the design of the low charge packages used for this facility and discuss how the ease of installation, ease of use, and high efficiency design, are making low charge, packaged ammonia systems the natural choice for the temperature-controlled storage industry.
Azane, part of the Star Refrigeration Group, started manufacturing in the US in 2014 and have a number of projects being installed in 2015. The presentation will give an overview of these projects and discuss the future of the low charge ammonia industry.
New developments in natural refrigerant equipment by Benoit Rodier, CIMCO Refrigeration
The case study will discuss a new, commercially available technology using ammonia and CO2. The system is a self-contained package for low temperature freezing applications. It consists of a newly designed semi hermetic ammonia screw compressor running at a low suction temperature to cool down a CO2 brine loop. A shell and plate cascade cooler is used as the evaporator as well as the condenser, significantly reducing the ammonia charge of the package. The CO2 is re-circulated via a hermetic pump located under the CO2 receiver vessel.
On the heat rejection side, the condenser rejects heat in a glycol loop connected to an outside fluid cooler. The oil cooling system also rejects into the same glycol loop. This warm loop can be used to meet heating requirements, for example slab heating, dock space heating, or fresh air intake pre heat.
The overall system performance is improved through the use of a very low delta approach on the heat exchanger and through the use of two economiser ports on an integrated two-stage semi hermetic screw compressor.
US Defense Commissary Agency project, ammonia/CO2 cascade refrigeration system, from design through completion by Rob Arthur, CTA Architects Engineers
CTA Architects Engineers, together with a project team including the Defense Commissary Agency, U.S. EPA Greenchill, Department of Energy, National Renewable Energy Lab and Hillphoenix, have designed and installed the U.S. Defense Commissary Agency’s first U.S. based ammonia/CO2 refrigeration system in San Antonio, Texas.
The commercial refrigeration system is made up of roof-top mounted primary ammonia water-cooled modules. These modules are grouped together and cascaded with a CO2 combined DX/pumped refrigeration system mounted on an internal mezzanine. Each module contains less than 10 lbs of ammonia, meaning the total installation has an ammonia charge of less than 100 lbs. The idea behind implementing a modular type system is to ensure flexibility in order to meet varying refrigeration needs. The case study will also look at life cycle costs and compare costs with a standard DX refrigeration system.