Natural refrigerants are ready for the North American market

By Simon Burkel, Jun 26, 2013, 16:36 4 minute reading

The two-day ATMOsphere America conference brought together 200 industry experts to discuss and explore the business case for natural refrigerants in North America. Increased attention was paid to CO2 system improvement and retrofit, as well as component development for increased efficiency in commercial and industrial refrigeration. The message across all of the presenting suppliers was clear: HFC-free solutions work, are economically viable, and are ready for the North American marke

GreenChill Platinum standard improves energy efficiency and reduces cost
Jeff Newel presented Hillphoenix’ installation at a Sprouts Farmers Market store in Thousand Oaks, California. The store meets GreenChill Platinum standards by using a second nature CO2 combined MT secondary and LT cascade refrigeration system (SNMT2LX), reducing the refrigerant charge to 0.5 lbs (0,227 kg)/kBtuH or less, and achieving an annual refrigerant emissions rate of no more than 5%. 
The system specifications are as follows:
  • The MT CO2 secondary system is characterised by fully flooded coils for efficient heat transfer, resulting in an evaporating temperature 2-3° F (1,1-1,65 °C) higher than in HFC systems. 
  • The LT cascade system uses a SmartValve system for efficient and cost-effective EEV control, resulting in a low heat gain, 30 to 50% lower than in HFC systems and a saturated suction temperature 1-2° F (0,55-1,1° C) higher than in HFC systems. 
A comparison of the CO2 emissions per year between the Sprouts’ system and a standard system shows a reduction of 67% in indirect CO2 emissions. As a conclusion, Mr. Newel presented the GreenChill gallons of milk financial impact calculator, demonstrating that a store using a traditional DX system has to sell 43,629 gallons (165,154 litres) of milk per year to recover the additional refrigerant lost compared to a GreenChill Platinum system. 
Retrofitting existing refrigeration systems with CO2 
Marc-André Lesmerises presented a project from Carnot Refrigeration, retrofitting an existing R22 refrigeration system with CO2 in a large supermarket. The case study demonstrated that it is no simple task to retrofit an existing system in an open store, but also clearly showed that the energy and cost savings of the new CO2 system are very compelling. The Carnot retrofit project demonstrates an average reduction in the supermarket’s monthly energy consumption of 10% compared to the HFC system employed before the retrofit. 
A total cost of ownership analysis over 10 years outlined the financial advantages of a retrofit compared to a minor renovation of an existing refrigeration system. Even if the first costs of a minor renovation are comparably small, the total cost of ownership of a retrofit are significantly lower, due to:
  • Predictable maintenance cost
  • Reduced energy consumption
  • Subsidies
  • 20 years life expectancy 
  • Improvement of food preservation
According to Mr. Lesmerises, the key question to ask oneself when considering a change in refrigeration system is not how much it will cost, but how much will it cost not to change?
CO2 heat pump for water heating and cooling in industrial food production
Merle Rocke, CEO at EcoThermics presented the company’s semi-hermetic compressors for CO2 heat pumps as well as the Eco2 Boost heat pump concept. 
Merle presented a case study in conjunction with Country Maid, a commercial bakery using a CO2 heat pump running on an Eco2Boost system. The heat pump provides cheaper water heating than gas heating. Country Maid selected a CO2 heat pump to meet its increasing requirements for hot water for sanitation and also to meet its need for air conditioning and dehumidification for food production and the packaging areas. 
The retrofit of the existing system demonstrates the CO2 heat pump’s capability to provide simultaneous water heating and space conditioning, helping Country Maid to exceed the targets it had originally set in terms of volume, heating and cooling capacity. The new CO2 heat pump for heating and cooling allows Country Maid to achieve cost savings of about $4,276 ( €3,280)/year compared to a conventional system using natural gas and electricity.
Integrated control systems help to conceal CO2 system complexity 
Michael Engelbright from CAREL outlined the evolution of CO2 refrigeration technology, which started in the late 90’s. According to Mr. Englebright, the main barrier hindering the introduction of CO2 systems today is training, which could be improved with one standardised training program.
CO2 development is nevertheless moving at a rapid pace. For example, hot gas defrost allows for lower life cycle cost and longer lifetime of the system. Today, there is also the possibility of parallel compression, which is being investigated for high ambient temperatures. 
According to Engelbright, the complex nature of CO2 systems can be simplified using CAREL systems, which offer operators remote access and visibility, allowing for better servicing. CAREL controllers consolidate everything into one system, leading to:
  • Reduced capital cost
  • Reduced installation cost and complexity
  • Faster maintenance
  • Improved interaction and synchronization between components
  • Increased safety and backup procedures
Making CO2 equipment reliable, affordable and more efficient 
Brian Porter presented on behalf of CO2 compressor manufacturer Dorin. Dorin today has the largest UL approved CO2 transcritical compressor range, the newest of which is the CO2 double stage transcritical compressor range, launched in 2012. There are now more than 100 of these units in the European market, but so far none yet in US. The new compressors feature a wide operating envelope  suitable for LT, HT and also heat pump applications. A comparison between various kinds of installation in large retail, convenience store and LT storage show that 2-stage compressors offer opportunities to decrease supermarkets capital and running costs, especially in LT only systems. 


By Simon Burkel

Jun 26, 2013, 16:36

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