Heat source apparatus and method of starting the apparatus

Abstract

After a chiller unit is started, an opening command of 10 pulses is output to an electronic expansion valve, and after a predetermined period of time (at the time of starting with unload) elapses, an opening command of 100 to 150 pulses is output to open the electronic expansion valve up to a predetermined opening degree. Thereafter, a discharge side refrigerant super-heat TdSH is monitored and a closing command of 1 pulse/sec is output to the electronic expansion valve to drive the same in a closing direction in a short time until TdSH becomes 20 K. After TdSH has reached 20 K, a closing command of 1 pulse/3 sec is output to the electronic expansion valve, until TdSH becomes 25 K, to drive the electronic expansion valve 3 at a smaller speed in the closing direction than that speed in the closing direction until TdSH becomes 20 K. After TdSH reaches 25 K, it is judged that an operation has shifted to a stable operation, and the opening degree of the electronic expansion valve is controlled while a suction side refrigerant super-heat TsSH is monitored.

1 . A heat source apparatus comprising a compressor, a condenser, an electronic expansion valve, an evaporator, a detector for detecting temperature of a refrigerant at a suction side of the compressor, a detector for detecting suction pressure of the compressor, a detector for detecting temperature of the refrigerant at a discharge side of the compressor, and a detector for detecting discharge pressure of the compressor, 
 the heat source apparatus further comprising an opening degree control part for controlling an opening degree of the electronic expansion valve, which opens the electronic expansion valve to a predetermined opening degree at the time of starting of the heat source apparatus, drives the electronic expansion valve in a direction, in which the electronic expansion valve is closed, until super-heat of the refrigerant at the discharge side of the compressor becomes a predetermined discharge side super-heat, and controls the opening degree of the electronic expansion valve so that super-heat of the refrigerant at the suction side of the compressor becomes a predetermined suction side super-heat, after the discharge side refrigerant super-heat has reached the predetermined discharge side super-heat.    
   
   
       2 . A heat source apparatus according to  claim 1 , wherein in a period of time, during which the electronic expansion valve is driven in the direction, in which the electronic expansion valve is closed, until the compressor discharge side refrigerant super-heat becomes the predetermined discharge side super-heat, the opening degree control part slows down a speed, at which the electronic expansion valve is closed, as the discharge side refrigerant super-heat becomes the predetermined discharge side super-heat from the time of starting.  
   
   
       3 . A heat source apparatus according to  claim 2 , wherein the opening degree control part outputs a drive signal for the closing direction to the electronic expansion valve in a first period until the compressor discharge side refrigerant super-heat becomes a first super-heat smaller than the predetermined discharge side super-heat, and outputs a drive signal for the closing direction to the electronic expansion valve in a second period longer than the first period until the compressor discharge side refrigerant super-heat becomes the predetermined discharge side super-heat after the compressor discharge side refrigerant super-heat has reached the first super-heat.  
   
   
       4 . A heat source apparatus according to  claim 2 , wherein the opening degree control part drives the electronic expansion valve at a first speed in the closing direction until the compressor discharge side refrigerant super-heat becomes a first super-heat smaller than the predetermined discharge side super-heat, and drives the electronic expansion valve at a second speed slower than the first speed until the compressor discharge side refrigerant super-heat becomes the predetermined discharge side super-heat after the compressor discharge side refrigerant super-heat has reached the first super-heat.  
   
   
       5 . A heat source apparatus according to  claim 1 , wherein the opening degree control part controls the opening degree of the electronic expansion valve 
 so that the discharge side refrigerant super-heat reaches the predetermined discharge side super-heat and the compressor suction side refrigerant super-heat becomes the predetermined suction side super-heat, and    so that the discharge side refrigerant super-heat falls within a predetermined discharge side super-heat range when the discharge side super-heat or the suction side super-heat exceeds a predetermined discharge side super-heat range or a predetermined suction side super-heat range, and    so that the compressor suction side refrigerant super-heat becomes the predetermined suction side super-heat after the discharge side refrigerant super-heat falls within the predetermined discharge side super-heat range.    
   
   
       6 . A heat source apparatus according to  claim 1 , wherein the opening degree control part controls the opening degree of the electronic expansion valve so that the discharge side refrigerant super-heat reaches the predetermined discharge side super-heat and the compressor suction side refrigerant super-heat becomes the predetermined suction side super-heat, and 
 changes the predetermined suction side super-heat to control the opening degree of the electronic expansion valve so that the compressor suction side refrigerant super-heat becomes the changed suction side super-heat when the discharge side super-heat or the suction side super-heat exceeds a predetermined discharge side super-heat range or a predetermined suction side super-heat range.    
   
   
       7 . A heat source apparatus according to  claim 1 , wherein when a suction pressure of the compressor becomes less than a predetermined pressure value in a period of time, during which the electronic expansion valve is driven in the direction, in which the electronic expansion valve is closed, until the compressor discharge side refrigerant super-heat becomes the predetermined discharge side super-heat, the opening degree control part drives the electronic expansion valve in an opening direction to make the same a predetermined opening degree and then controls the opening degree of the electronic expansion valve until the compressor suction side refrigerant super-heat becomes a predetermined suction side super-heat.  
   
   
       8 . A heat source apparatus according to  claim 1 , wherein the compressor is a screw compressor.  
   
   
       9 . A heat source apparatus according to  claim 1 , wherein the refrigerant is a pseudo azeotropic refrigerant or a single refrigerant.  
   
   
       10 . A method of starting a heat source apparatus comprising a compressor, a condenser, an electronic expansion valve, an evaporator, a detector for detecting temperature of refrigerant at a suction side of the compressor, a detector for detecting suction pressure of the compressor, a detector for detecting temperature of refrigerant at a discharge side of the compressor, and a detector for detecting discharge pressure of the compressor, wherein 
 the electronic expansion valve is opened to a predetermined opening degree at the time of starting of the heat source apparatus,    the electronic expansion valve is driven in a direction, in which the electronic expansion valve is closed, until compressor discharge side refrigerant super-heat becomes a predetermined discharge side super-heat, and    the opening degree of the electronic expansion valve is controlled so that the compressor suction side refrigerant super-heat becomes a predetermined suction side super-heat, after the discharge side refrigerant super-heat has reached the predetermined discharge side super-heat.