System and method of use of expansion engine to increase overall fuel efficiency

Abstract

A system of increasing overall fuel efficiency of a facility including a gas expansion engine for receiving a supply of pressurized gas of a first pressure and first temperature and outputting a tail gas of a second lower temperature and lower pressure. The expansion engine having a rotatable shaft as an energy output. An electric generator and/or other rotatable machinery is coupled to the rotatable shaft of the gas expansion engine. A heat exchanger may be used to transmit coldness from the tail gas of the expansion engine to an HVAC apparatus or an ice making apparatus or other plant process cooling equipment. A method of increasing overall fuel efficiency for a facility utilizing the afore described equipment is taught in the present invention.

1 . A system for increasing overall fuel efficiency of an HVAC system comprising: 
 a reciprocating type gas expansion engine for receiving a supply of pressurized natural gas from a natural gas pipeline of a first pressure and first temperature, said expansion engine having a rotatable shaft as an energy output, said expansion engine outputting a tail gas having a second lower temperature and second lower pressure;    at least one electric generator coupled to said rotatable shaft of said gas expansion engine;    an HVAC apparatus; and    at least one heat exchanger with an inlet portion receiving tail gas from the gas expansion engine and an outlet portion providing chilled gas and/or liquid to the HVAC apparatus.    
   
   
       2 . The system of  claim 1  wherein a gas expansion engine and electric generator are preassembled as a single unit and installed as a single unit.  
   
   
       3 . The system of  claim 1  wherein the gas expansion engine and the generator are mounted on a skid for reduced installation time.  
   
   
       4 . A system for increasing overall fuel efficiency of an HVAC system comprising: 
 a reciprocating type gas expansion engine for receiving a supply of pressurized natural gas from a natural gas pipeline of a first pressure and first temperature, said expansion engine having a rotatable shaft as an energy output, said expansion engine outputting a tail gas having a second lower temperature and second lower pressure;    at least one compressor coupled to said rotatable shaft of said expansion engine;    an HVAC apparatus; and    at least one heat exchanger with an inlet portion receiving tail gas from the expansion engine and an outlet portion providing chilled gas and/or liquid to the HVAC apparatus.    
   
   
       5 . The system of  claim 4  wherein the gas expansion engine and compressor are preassembled as a single unit and installed as a single unit.  
   
   
       6 . The system of  claim 4  wherein the gas expansion engine and the compressor are mounted on a skid for reduced installation time.  
   
   
       7 . A method of increasing fuel efficiency comprising: 
 providing a supply of pressurized natural gas from a natural gas pipeline having a first pressure and first temperature to the inlet of a reciprocating type gas expansion engine;    directing at least a portion of the outlet gas from the outlet of the gas expansion engine to an inlet portion of a heat exchanger;    extracting coolness in the heat exchanger from the inlet gas to the heat exchanger; and    using the coolness extracted in the heat exchanger from the inlet gas to the exchanger in an HVAC cooling device.