Low cost high efficiency ice machine

Abstract

Disclosed are ice making machines which use aluminum as an alternative to copper in the ice making machine evaporator and also use an alternate coolant/refrigerant specifically targeted to provide improved heat transfer transport properties and higher heat capacitance than conventional HFC coolant/refrigerants. Optionally, rotary compressors are used in place of conventional reciprocating compressors, further enhancing performance for the ice making machine. The disclosed ice making machines maintain high efficiency and ice output, and provide equal or better energy efficiency than comparative ice making machines. At the same time, savings are realized in the material cost for the evaporator, and resulting from the combined effects of lower density and lower metal cost/unit weight offered by aluminum as compared to copper.

What is claimed is: 
     
         1 . An ice making machine comprising:
 a coolant/refrigerant system comprising coolant/refrigerant, a compressor, a condenser, an evaporator, an expansion device, a suction-liquid heat exchanger, a hot gas valve for directing hot gases from the compressor to the evaporator, and interconnecting lines therefor, wherein the compressor is a rolling piston type device.   
     
     
         2 . An ice making machine according to  claim 1 , wherein the compressor is a rotary rolling piston type hermetic compressor. 
     
     
         3 . An ice making machine comprising:
 a coolant/refrigerant system comprising coolant/refrigerant, a compressor, a condenser, an evaporator, an expansion device, a suction-liquid heat exchanger, a hot gas valve for directing hot gases from the compressor to the evaporator, and interconnecting lines therefor, wherein the coolant/refrigerant has a forced convection heat transfer coefficient of at least about 1000 Btu/hr.-ft. 2 -F, a liquid thermal conductivity of at least about 0.060 Btu/hr.-ft.-F at 0° F., and a volumetric refrigeration capacity of at least about 75 Btu/ft. 3      
     
     
         4 . An ice making machine according to  claim 3 , wherein the coolant/refrigerant is comprised of R-32. 
     
     
         5 . An ice making machine according to  claim 3 , wherein the coolant/refrigerant is comprised of R-410-A. 
     
     
         6 . An ice making machine comprising:
 a coolant/refrigerant system comprising coolant/refrigerant, a compressor, a condenser, an evaporator, an expansion device, a suction-liquid heat exchanger, a hot gas valve for directing hot gases from the compressor to the evaporator, and interconnecting lines therefor, wherein the evaporator is comprised of aluminum.   
     
     
         7 . An ice making machine according to  claim 6 , wherein the evaporator is brazed or cast aluminum. 
     
     
         8 . An ice making machine according to  claim 7 , wherein the evaporator is brazed aluminum and is coated. 
     
     
         9 . An ice making machine according to  claim 8 , wherein the evaporator is coated with a coating selected from electroless nickel coating and electrocoated polymer coating. 
     
     
         10 . An ice making machine comprising:
 a coolant/refrigerant system comprising coolant/refrigerant, a compressor, a condenser, an evaporator, an expansion device, a suction-liquid heat exchanger, a hot gas valve for directing hot gases from the compressor to the evaporator, and interconnecting lines therefor, wherein the evaporator is comprised of aluminum, the coolant/refrigerant has a forced convection heat transfer coefficient of at least about 1000 Btu/hr.-ft. 2 -F, a liquid thermal conductivity of at least about 0.060 BtuThr.-ft.-F at 0° F., and a volumetric refrigeration capacity of at least about 75 Btu/ft. 3  and the compressor is a rotary compressor.   
     
     
         11 . An evaporator for use in an ice making machine, said evaporator comprised of coated and brazed aluminum brazed with a brazing material comprised of an aluminum alloy having an aluminum content of between about 87%-89% and a silicon content of about 11%-13%, and coated with a coating selected from electroless nickel coating and electrocoated polymer coating. 
     
     
         12 . A method of making ice in an ice making machine, said method comprising flowing water over an evaporator comprised of aluminum, and cooling the evaporator using a coolant/refrigerant having a forced convection heat transfer coefficient of at least about 1000 Btu/hr.-ft.-F, a liquid thermal conductivity of at least about 0.060 Btu/hr.-ft.-F at 0° C., and a volumetric refrigeration capacity of at least about 75 Btu/ft. 3 .