It would be desirable to design an azeotropic ammonia mixture with higher pressure to avoid the disadvantages of pure ammonia. The objective is to determine the appropriate proportions for a mixture that would allow this blend to be employed for food blast freezing applications in the temperature range from - 55°C to + 50°C.
Ammonia has a high NBP and low specific heat. Low evaporating temperatures lead to sub- atmospheric operation allowing leakage of air into the system
It would be desirable to design an azeotropic ammonia mixture with higher pressure to avoid the disadvantages of pure ammonia. The objective is to determine the appropriate proportions for a mixture that would allow this blend to be employed for food blast freezing applications in the temperature range from - 55°C to + 50°C.
Ammonia has a high NBP and low specific heat. Low evaporating temperatures lead to sub- atmospheric operation allowing leakage of air into the system, and high compressor discharge temperatures. The selected blend overcomes these drawbacks by significantly reducing the NBP and allowing lower discharge temperatures. It will displace liquid nitrogen and carbon dioxide cryogenic freezers as well as carbon dioxide / ammonia cascade and two stage ammonia systems. The following findings were made relative to R717:
COP similar Volumetric refrigerating effect (VRE) higher
Discharge temperature significantly lower, improving reliability Improved heat transfer
Higher evaporating temperatures
Degradation of COP and refrigerating capacity with increasing temperature lift reduced
Patents have been filed and published and global licensees are now being sought.
Ammonia has a high NBP and low specific heat. Low evaporating temperatures lead to sub- atmospheric operation allowing leakage of air into the system, and high compressor discharge temperatures. The selected blend overcomes these drawbacks by significantly reducing the NBP and allowing lower discharge temperatures. It will displace liquid nitrogen and carbon dioxide cryogenic freezers as well as carbon dioxide / ammonia cascade and two stage ammonia systems. The following findings were made relative to R717:
COP similar Volumetric refrigerating effect (VRE) higher
Discharge temperature significantly lower, improving reliability Improved heat transfer
Higher evaporating temperatures
Degradation of COP and refrigerating capacity with increasing temperature lift reduced
Patents have been filed and published and global licensees are now being sought.
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By Colmac Coil manufacturing Inc. , published Nov 28, 2016 - 63 pages
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