System and method for compression of fluids

Abstract

A fluid compressor for compressing fluids and a method for operating the same are provided. The fluid compressor includes a compression chamber with an inlet for the fluid and an outlet for compressed fluid. The fluid compressor further includes a piston disposed within the compression chamber. The fluid compressor includes a driving system that includes piezoelectric actuator configured to cause displacement of the piston in the compression chamber. The driving system further includes an amplifying element that is coupled to the piezoelectric actuator in the direction of the movement of the piston to enhance the displacement of the piston caused by the piezoelectric actuator. One end of the amplifying element is fixed to a base of the fluid compressor and the piezoelectric actuator is disposed between the amplifying element and the piston.

What is claimed is: 
     
         1 . A system for controlling temperature of an enclosed space, the system comprising:
 a fluid compressor to compress a coolant fluid, wherein the fluid compressor comprises:
 a compression chamber having an inlet for the coolant fluid and an outlet for the compressed coolant fluid; 
 a piston disposed within the compression chamber; 
 a driving system comprising:
 a piezoelectric actuator coupled to the piston, configured to cause lateral displacement of the piston in the compression chamber in response to an excitation signal; and 
 an amplifying element operatively coupled to the piezoelectric actuator in the direction of the movement of the piston, the amplifying element being configured to enhance the displacement of the piston caused by the piezoelectric actuator, one end of the amplifying element being fixed to a base of the fluid compressor, the piezoelectric actuator being disposed between the amplifying element and the piston; 
 
   a condenser operatively coupled to the fluid compressor, to remove the heat of the compressed high temperature coolant fluid;   an expansion valve to reduce pressure of the compressed coolant fluid entering from the condenser and further reduce temperature of the compressed high temperature coolant fluid; and   an evaporator to control temperature of the enclosed space by drawing heat from the enclosed space through the coolant fluid from the expansion valve.   
     
     
         2 . The system as recited in  claim 1 , further comprising a fan that blows air from the enclosed space across the cooled coolant fluid in the evaporator. 
     
     
         3 . The system as recited in  claim 1 , wherein the condenser comprises coiled tubes to carry the compressed coolant fluid. 
     
     
         4 . The system as recited in  claim 1 , further comprising an excitation sub-system to provide the excitation signal to the piezoelectric actuator. 
     
     
         5 . The system as recited in  claim 4 , further comprising a feedback controller operatively coupled to the excitation sub-system to control at least one of frequency or amplitude of the excitation signal. 
     
     
         6 . The system as recited in  claim 5 , wherein the feedback controller comprises at least one of a pressure sensor, stroke sensor, and temperature sensor. 
     
     
         7 . A fluid compressor comprising:
 a compression chamber having an inlet for a fluid to be compressed and an outlet for compressed fluid;   a piston disposed within the compression chamber for compressing the fluid;   a driving system for the piston comprising,
 a piezoelectric actuator coupled to the piston, configured to cause lateral displacement of the piston in the compression chamber in response to an excitation signal, and 
 an amplifying element operatively coupled to the piezoelectric actuator in the direction of the movement of the piston, the amplifying element being configured to enhance the displacement of the piston caused by the piezoelectric actuator, one end of the amplifying element being fixed to a base of the fluid compressor, the piezoelectric actuator being disposed between the amplifying element and the piston. 
   a feedback controller to control at least one of frequency and amplitude of the excitation signal provided to the piezoelectric actuator.   
     
     
         8 . The fluid compressor as recited in  claim 7 , further comprising an excitation sub-system for providing the excitation signal to the piezoelectric actuator to cause the displacement in the piezoelectric actuator. 
     
     
         9 . The fluid compressor as recited in  claim 7 , wherein the feedback controller comprises at least one of a pressure sensor, a stroke sensor, and a temperature sensor. 
     
     
         10 . The fluid compressor as recited in  claim 7 , further comprising a driving system comprising a plurality of piezoelectric actuators and a plurality of amplifying elements stacked in parallel to displace the piston back and forth in the compressor chamber. 
     
     
         11 . A driving system comprising:
 a piezoelectric actuator coupled to a piston of a fluid compressor, configured to cause lateral displacement of the piston in a compression chamber, and   an amplifying element operatively coupled to the piezoelectric actuator in the direction of the movement of the piston, the amplifying element being configured to enhance the displacement of the piston caused by the piezoelectric actuator, one end of the amplifying element being fixed to a base of the fluid compressor, the piezoelectric actuator being disposed between the amplifying element and the piston.   
     
     
         12 . The driving system as recited in  claim 11 , further comprising an excitation sub-system for providing an excitation signal to the piezoelectric actuator to cause the displacement in the piezoelectric actuator. 
     
     
         13 . The driving system as recited in  claim 12 , further comprising a feedback controller coupled to the excitation sub-system to control at least one of a frequency and an amplitude of the excitation signal provided to the piezoelectric actuator. 
     
     
         14 . The driving system as recited in  claim 13 , wherein the feedback controller comprises at least one of a pressure sensor, a stroke sensor, and a temperature sensor. 
     
     
         15 . The driving system as recited in  claim 11 , wherein the amplifying element comprises a coiled spring that is placed in a position parallel to a direction of movement of the piston. 
     
     
         16 . The driving system as recited in  claim 11 , wherein the amplifying element comprises a pre-buckled beam. 
     
     
         17 . The driving system as recited in  claim 11 , wherein the piezoelectric actuator comprises a stack actuator. 
     
     
         18 . The driving system as recited in  claim 11 , wherein the piezoelectric actuator comprises an amplified piezoelectric actuator. 
     
     
         19 . The driving system as recited in  claim 11 , further comprising a plurality of piezoelectric actuators and a plurality of amplifying elements stacked in parallel to displace the piston back and forth in the compressor chamber. 
     
     
         20 . A method of operating a fluid compressor, the method comprising:
 monitoring at least one of fluid pressure and fluid temperature in a compression chamber of the fluid compressor, comprising a piston that is laterally displaced back and forth in the compression chamber by a driving system, wherein the driving system comprises:
 a piezoelectric actuator coupled to the piston, and 
 an amplifying element operatively coupled to the piezoelectric actuator in the direction of the movement of the piston, the amplifying element being configured to enhance the displacement of the piston caused by the piezoelectric actuator, one end of the amplifying element being fixed to a base of the fluid compressor, the piezoelectric actuator being disposed between the amplifying element and the piston; 
   comparing at least one of monitored fluid pressure and fluid temperature with a reference value; and   providing an excitation signal to the piezoelectric actuator based on the comparison result.   
     
     
         21 . The method as recited in  claim 20 , further comprising disposing a plurality of piezoelectric actuators with a plurality of amplifying elements, in a position parallel to the piston of the fluid compressor.