The many facets of CO2 as a refrigerant at ATMOsphere America 2014

By Janet Thompson, Apr 23, 2014, 17:47 4 minute reading

Several leading companies such as Stellar & CRT Design, Carrier, KAV Consulting and Thar Geothermal will be presenting their latest projects and product developments using CO2 during the parallel technology case study sessions at the 3rd annual ATMOsphere America 2014. The case studies feature a variety of topics from CO2 systems for cooling office/commercial spaces and container shipping units using CO2 to CO2 evaporative condensers, ev

The 3rd annual ATMOsphere America 2014, which will take place from 18 – 19 June in San Francisco, highlights the variety of applications using CO2 refrigerant. The parallel Technology Case Study Sessions cover HVAC, transport refrigeration and heat pump applications.

Industrial Ammonia Systems used for cooling in commercial/office buildings by Luke Facemyer, Stellar and Chuck Taylor, CRT Design

This case study includes three recent, distinct projects utilising an industrial ammonia system to provide cooling to office/commercial spaces. The first project is a large greenfield food processing plant in which the ammonia system was expanded in order to also serve 20,000 sq ft of office space. The second project utilises both ammonia and CO2 systems to cool a mixed-use building. The third project is a retrofit project where several conventional HVAC units were removed from a commercial building and replaced with an ammonia system. Energy and cost analysis will be presented for each of the three projects.

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.

Natural Refrigerant, Enhanced Geothermal Heating & Cooling Solutions by Lalit Chordia and Marc Portnoff, Thar Geothermal LLC

Thar Geothermal, LLC has developed commercial heating and cooling systems that are rooted in nature’s design, and that meet the triple bottom line of enhanced energy efficiency, reduced operating costs, and reduced environmental footprint. The presentation will cover the design and implementation of an R744 direct exchange, ground source heat pump (DX-GSHP) system. This includes examples of 1) how versatile the technology can be with regards to interfacing with a range of standard HVAC&R systems and 2) real world system performance.

About ATMOsphere America 2014
18 - 19 June at The Westin Market Street in San Francisco, California

ATMOsphere America 2014, the meeting place for around 250 HVAC&R industry stakeholders active or interested in the field of natural refrigerants, provides an opportunity to discuss the latest natural refrigerant technology developments, market trends and regulatory issues. This year, the conference features several parallel technology case study sessions focusing on commercial refrigeration, HVAC, heat pumps and industrial refrigeration and other applications. Given this year’s West Coast location, the event offers an optional Napa Valley Wine Tour and site visit for participants.


By Janet Thompson

Apr 23, 2014, 17:47

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