Financial & Energy Analysis of Mechanical Refrigeration vs. Alternatives
Using liquid nitrogen or dry ice for processing is a major consumable operating cost. Although using these consumables is perceived as a simpler solution it is very inefficient, and comes with asphyxiation hazards and logistical overheard.
Analysis comparing mechanical refrigeration systems vs. open loop refrigeration via liquid nitrogen and liquid CO2 can be found in the article cited. As shown in the analysis for a meat freezing application mechanical refrigeration even accounting for energy, maintenance and capital costs is approximately 3-8 times more efficient per unit of mass to be frozen. Further analysis and projections for the refrigeration systems offered by GPS in specific processing scenarios are offered below.
Dry Ice(CO2) vs. Mechanical Refrigeration: Butane Case
Specific comparisons can be drawn for butane based on the following assumption 1:7 biomass to butane solvent mass ratio and 2:1 mass ratio of dry ice consumed per unit mass of butane chilled. These assumptions are based on a general survey of lab operators reporting their rates of dry ice usage.
The findings in figure 3 are slightly skewed as the 42 TR system includes an additional cool and heating loop(3 loops total) which is not accounted for in this analysis, whereas the 2.5 & 4 TR systems only include a one cooling loop, and the 14.5 and 15 TR systems include one cooling loop and one heat recycling loop. If the economic effects of the additional cooling and heating loops were taken into effect the results would appear slightly more favorable for the 14.5, 15, and especially 42 TR model(s).
Note assumptions and simplifications were made in this analysis which is only intended to represent overall trends not exact results. Contact GPS for more detailed analysis of your specific use case.
It is our contention based on first order analysis that once total ownership and consumable costs are compared mechanical refrigeration can pay off within 1-3 years or less depending on implementation and provide many advantages over other cooling methods.
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