Liquid chiller system with external expansion valve

Abstract

A liquid chiller system utilizing a refrigerant capable of possessing a liquid state and a gas/vapor state, the refrigerant being cycled through a closed loop assembly of a compressor, a condenser, an evaporator, and an expansion valve external to the evaporator. The compressor may have a lower integrated reservoir and the evaporator may have an upper dedicated reservoir such that separate, dedicated separator or receiver vessels are not required. The condenser may be positioned above the eccentric evaporator such that liquid refrigerant flows by gravity from the condenser to the evaporator.

What is claimed is: 
     
         1 . A method of operating a liquid chiller system, the method comprising:
 passing a refrigerant in a gaseous stage through a cooling conduit in a portion of a condenser unit;   lowering a temperature of the refrigerant in a gaseous stage;   based upon the lowering of the temperature of the refrigerant, converting at least some of the refrigerant from the gaseous stage into a liquid stage;   storing the refrigerant in a liquid stage in a portion of piping in fluid communication with an expansion valve, said piping located in a flow position before an expansion valve, wherein the expansion valve is located external to an evaporator and contains at least 10% of refrigerant within the expansion valve in a liquid stage;   transporting refrigerant in a liquid stage from the expansion valve into an evaporator;   flowing a process liquid through process liquid conduits in the evaporator   partially evaporating the refrigerant in a liquid stage into refrigerant in a gaseous stage within the evaporator based upon absorption of heat from the process liquid in the evaporator;   cooling the process liquid based upon the evaporating the refrigerant in a liquid stage into refrigerant in a gaseous stage;   compressing some of the refrigerant in a gaseous stage with a compressor;   passing the compressed refrigerant in a gaseous stage to the condenser where the compressed refrigerant is in a gaseous stage; and   converting the refrigerant in a gaseous stage into refrigerant in a liquid stage; and   storing a portion of the refrigerant in a portion of the tubing before the expansion valve comprising sufficient capacity to obviate a need for a separate, distinct reservoir vessel.   
     
     
         2 . The method of  claim 1  additionally comprising the step of storing the integrated refrigerant in a gaseous stage reservoir comprising sufficient capacity to obviate the need for a separate, distinct separator vessel. 
     
     
         3 . The method of  claim 2 , the storage of a portion of the refrigerant in piping in fluid communication with the expansion valve comprises sufficient capacity to obviate a need for a separate, distinct reservoir vessel. 
     
     
         4 . The method of  claim 3 , additionally comprising the step of controlling a flow of refrigerant between the condenser and the evaporator. 
     
     
         5 . The method of  claim 4 , additionally comprising the step of operating a flow control device disposed between the condenser and the evaporator to control a flow of the process liquid in a process liquid flow circuit. 
     
     
         6 . The method of  claim 5 , additionally comprising the step of retaining a portion of the refrigerant from the condenser in a liquid stage in the liquid reservoir. 
     
     
         7 . The method of  claim 5 , additionally comprising the step of delivering the refrigerant in a liquid stage from the condenser to the evaporator without passage through a separate reservoir vessel. 
     
     
         8 . The method of  claim 5 , additionally comprising the step of delivering the refrigerant in a gaseous stage from the eccentric condenser to the compressor without passage through a separate separator vessel. 
     
     
         9 . The method of  claim 5  wherein the cooling conduit comprises a plate. 
     
     
         10 . The method of  claim 5  wherein the cooling conduit comprises a coil. 
     
     
         11 . The method of  claim 5  wherein the cooling conduit comprises a tube. 
     
     
         12 . The method of  claim 5  wherein the process liquid flow circuit comprises a plate. 
     
     
         13 . The method of  claim 5  wherein the process liquid flow circuit comprises a coil. 
     
     
         14 . The method of  claim 5  wherein the process liquid flow circuit comprises a tube. 
     
     
         15 . The method of  claim 5  wherein the refrigerant in a liquid stage comprises ammonia and the process fluid comprises glycol. 
     
     
         16 . The method of  claim 15  additionally comprising the step of changing a temperature of 2,200 gallons per minute or more of the glycol process liquid from about 33 degrees Fahrenheit or more to 28 degrees Fahrenheit or less. 
     
     
         17 . The method of  claim 15  wherein the change in temperature of temperature of the 2,200 gallons per minute or more of the glycol process liquid from about 33 degrees Fahrenheit or more to 28 degrees Fahrenheit or less, is accomplished utilizing less than 500 pounds of ammonia as the refrigerant in a liquid stage. 
     
     
         18 . The method of  claim 15  wherein less than about 40 pounds of refrigerant in a liquid stage is present in the condenser. 
     
     
         19 . The method of  claim 1  additionally comprising the step of delivering refrigerant from the condenser in a liquid stage though an expansion valve thereby evaporating at least some of the refrigerant in a liquid stage into a liquid and vapor mixture. 
     
     
         20 . The method of  claim 1  additionally comprising the step of storing the liquid and vapor mixture in the evaporator.