Super Efficient Plug and Play Ammonia Engine Rooms

ScanPAC Self-Contained Dual Stage NH3 Engine Rooms

Ammonia is steadily advancing into application areas previously reserved for synthetic HFC refrigerants. This development has, of course, been encouraged by the introduction 1 July 2012 of the carbon equivalent levy on hydrofluorocarbon (HFC) and other synthetic refrigerants. Ammonia is a naturally occurring substance. It belongs to the category of natural refrigerants. It does therefore not attract any environmental levies. The other advantage of ammonia is the superior cycle efficiency when used as a refrigerant in a vapour compression refrigeration system. The greater cycle efficiency is a result of the more favourable thermophysical and transport properties of ammonia. The very low molecular weight of NH3 (17.03 kg/kmol) reduces pressure drops in pipe lines, fitting and valves. The 5-6 times greater thermal conductivity of NH3 in the liquid phase compared with HFC's has a very favourable impact on film coefficients in heat exchangers. Finally, the very high latent heat of NH3 ensures that a much smaller system mass flow is required than for HFC's. Self-contained, high efficiency, dual stage NH3 engine rooms are ideal either for converting an existing HFC based facility to NH3 or for servicing a new facility. The packaged refrigeration systems are semi-standardized, but incorporate sufficient flexibility to enable matching up to individual customer requirements. For small to medium size refrigerated warehouse facilities, actual refrigeration capacity requirements are never the same from one facility to the next. The same applies to the split between low temperature (freezer) duty and medium temperature (chiller) duty. By varying compressor sizes, compressor numbers, compressor duties and compressor capacity control methodology, packaged systems can be tailored to match individual needs exactly. Compared with HFC based single stage refrigeration plants dating back to the era prior to the introduction of the carbon equivalent HFC levy, these new NH3 based packages feature annual energy consumption values which are around 40% lower. These are empirical energy consumption comparisons based on actual kWh-meter readings - please contact Scantec for a copy of the technical paper providing the details. The additional investment in a future-proof NH3 based refrigeration system over and above an equivalent HFC based air cooled systems is in most cases returned in 3 to 6 years.

What is Low Charge NH3?

During the month of October 2016, 197 countries decided to amend the Montreal Protocol to include HFC refrigerants. This means Freons (HFC's) are scheduled for a phase-down similar to CFC's. Low charge NH3 refrigeration systems are the totally future proof and proven alternative to HFC based systems. Other significant advantages are documented energy performance improvements of up to 67% compared with single stage, air cooled Freon systems with electric defrost, 30-50 times lower NH3 inventory in the warehouse air coolers and 3-5 times lower overall NH3 inventory compared with conventional NH3 plants with liquid overfeed. Low charge NH3 systems - whether retrofits or new plants - pay for themselves in 3 to 6 years based on energy savings alone. Low charge NH3 systems are ideal retrofits for industry standard, air cooled Freon based refrigeration systems with refrigeration capacities from about 100 kW and upwards. HFC refrigerants are powerful global warming agents. Phasing out these substances has the potential to reduce global warming by 0.5oC between now and 2100. There are only five refrigerants that will be totally immune from future application restrictions on environmental grounds. These are ammonia, carbon dioxide, hydrocarbons, water and air. Australia is committed to an 85% HFC phase-down scheduled to commence in 2018 with completion by 2036. The result will be rapidly escalating HFC refrigerant costs caused by supply/demand mechanisms.   Read More
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