Aqueous ammonia solution cooling absorption refrigeration driven by fishing boat diesel exhaust heat

A solution cooling absorption（SCA）approach is proposed to modify the aqueous ammonia absorption refrigerat-ion cycle using the strong solution from the absorber to cool the forepart of the absorption in the cycle for reclaiming some portion of absorption heat.As a consequence of raised temperature at the inlet,the strong solution partially boils at the outlet of the solution heat exchanger,and diminishes the thermal heat consumption of the heat source.The calculation results show that the coefficient of performance（COP）of this modified cycle is about 28.3% higher than that of the traditional cycle under typical conditions;while the required heat transfer area of the total heat exchangers of the cycle is somewhat less than that of the traditional one.The capacity of refrigeration with the new absorption cycle is more than doubled in contrast to the adsorption scheme with an identical configuration.It is sufficient to supply a fishing boat the chilling capacity for preservation of fishing products with the modified cycle chiller driven by its diesel engine exhaust.

Energy,exergy,economic,and environmental compromising performance of dual-stage evaporation-ammonia hybrid compressioneabsorption refrigeration system for the cooling supply of keto-benzene dewaxing process

Absorption refrigeration systems driven by low-temperature waste heat is one way to achieve“carbon neutrality.”Meanwhile,the keto-benzene dewaxing equipment needs a cooling capacity of 5 MW,with refrigeration temperature of-10℃and-25℃.This paper researches the feasibility of dual-stage evaporation-ammonia hybrid compressioneabsorption refrigeration system(DSE-AHCARS)replacing the vapor compression refrigeration system for keto-benzene dewaxing process based on energy,exergy,economic,and environmental(4E)analysis.At the primary-and secondary-stage evaporation temperature of 0 and-23℃,respectively,the coefficient of performance(COP)reaches the maximum value of 0.85;however,COP-electricity reaches the minimum value of 8.1.When the secondary-stage refrigeration temperature is-23℃,CO_(2)emission increases from 1150 t·a^(-1)to 3600 t·a^(-1),and life cycle climate performance increases from 3.29×10^(4) to 7.7×10^(4) t,with the primary-stage refrigeration temperature being-15-0℃,as well as matching three parameters to ensure the 4E compromising performance by the multi-objective optimization.To guarantee that the life cycle climate performance is less than 5.5×10^(4)t,the payback period is<2 a,and COP is>0.6 at the optimal operation ranges,such that the refrigeration temperature difference between primary stage and secondary stage is within 20℃.The power of DSE-AHCARS was reduced by 77%compared with the vapor-compression refrigeration system.Therefore,the DSE-AHCARS can reduce CO_(2)emissions by about 6250 t·a^(-1)and save 1.2×10^(5)t of CO_(2)in the life cycle climate performance term.This result shows that the DSE-AHCARS can completely replace the vapor-compression refrigeration system.