Variable Capacity Modular Combined Refrigerating Installation by Frequency Conversion

Abstract

A variable capacity modular combined refrigerating installation, which has several modular refrigerating units. Each modular unit has a refrigerating circle, which includes a refrigerating compressor set ( 1 ), an evaporator ( 4 ) and a condenser ( 10 ). A flow control valve ( 6 ) is mounted at the refrigerating medium inlet/outlet port of the evaporator ( 4 ); and/or a flow control valve ( 11 ) is mounted at the inlet/outlet port of the condenser ( 10 ). The refrigerating compressor set ( 1 ) comprises an adjustable frequency motor ( 1 A) and a compressor ( 1 B) with magnetic suspend bearings. Each modular unit is also provided with an inlet pressure sensor ( 26 ) and/or discharge pressure sensor ( 27 ). The installation provided with a refrigerating water temperature sensor ( 19 ), a sensor ( 20 ) for pressure difference between supply and return at the installation side and a sensor ( 21 ) for pressure difference between supply and return at the load side; and a sensor ( 22 ) for pressure difference between supply and return at the installation side. The present invention can decrease the power consumption of the air conditioning system and provide a convenient and improved control.

1 . A variable capacity modular combined refrigerating installation, which consists of multiple refrigerating modular units, each modular unit comprising one or more refrigerating cycles which includes a refrigerating medium and refrigerating compressor set, an evaporator and a condenser, comprising:
 a flow control valve for the refrigerating medium mounted at one of the refrigerating medium inlet/outlet ports of the evaporator, and a flow control valve of the refrigerating medium is mounted at least one of the inlet/outlet ports of the condenser; and   a frequency conversion motor and a compressor with magnetic suspension bearings disposed as part of the refrigerating compressor set.   
   
   
       2 . A modular combined refrigerating installation according to  claim 1 , further comprising at least one of:
 a suction pressure sensor mounted at the suction port of the compressor set to transfer pressure information for controlling the working capacity of the compressor set; and   a discharge pressure sensor mounted at the outlet port of the compressor to transfer pressure information for controlling the opening ratio of said flow control valve of cooling medium.   
   
   
       3 . A modular combined refrigerating installation according to  claim 1 , further comprising:
 a temperature sensor to collect and transfer parameters of the refrigerating water temperature of the installation for controlling the opening ratio of said flow control valve of refrigerating medium.   
   
   
       4 . A modular combined refrigerating installation according to  claim 1 , further comprising:
 a sensor for pressure difference between supply and return at the installation side and a sensor for pressure difference between supply and return at the load side in the refrigerating medium system, to collect and transfer parameters of the pressure difference between supply and return for calculating and controlling a working frequency of the delivery pump.   
   
   
       5 . A modular combined refrigerating installation according to  claim 1 , further comprising:
 a sensor for pressure difference between supply and return at the installation side in the cooling medium system to calculate and control a working frequency of the delivery pump.   
   
   
       6 . A modular combined refrigerating installation according to  claim 1 , further comprising:
 a magnetic bearing sensor is mounted at each magnetic bearing of the compressor.   
   
   
       7 . A modular combined refrigerating installation according to  claim 1 , wherein said evaporator is a plate heat exchanger of full liquid evaporation type, which has an inner core and an outer shell, said core is formed by welding a certain number of metal plate of certain geometric shape according to a predetermined rule; said outer shell is a barrel shaped container with a circle or square section; and in said evaporator, there are two or more kinds of medium flowing channels which are isolated from each other. 
   
   
       8 . A modular combined refrigerating installation according to  claim 7 , wherein each modular unit is provided with an economizer, and the liquid cryogen from said condenser is divided into two parts, one part after being throttled super cools the other part, while said one part absorbs heat and evaporates itself. 
   
   
       9 . A modular combined refrigerating installation according to  claim 8 , wherein a liquid level control throttling expansion device is mounted between said condenser and the plate heat exchanger of full liquid evaporation type. 
   
   
       10 . A modular combined refrigerating installation according to  claim 9 , wherein a gas-liquid separator is mounted between the suction port of the compressor and the plate heat exchanger of full liquid evaporation type. 
   
   
       11 . A modular combined refrigerating installation according to  claim 1 , wherein the general circuit of the modular refrigerating installation is controlled by a master controller, and the circuit of each modular unit is controlled by a microprocessor controller. 
   
   
       12 . A modular combined refrigerating installation according to  claim 2 , wherein the general circuit of the modular refrigerating installation is controlled by a master controller, and the circuit of each modular unit is controlled by a microprocessor controller. 
   
   
       13 . A modular combined refrigerating installation according to  claim 2 , further comprising:
 a temperature sensor to collect and transfer parameters of the refrigerating water temperature of the installation for controlling the opening ratio of said flow control valve of refrigerating medium.   
   
   
       14 . A modular combined refrigerating installation according to  claim 2 , further comprising:
 a sensor for pressure difference between supply and return at the installation side and a sensor for pressure difference between supply and return at the load side in the refrigerating medium system, to collect and transfer parameters of the pressure difference between supply and return for calculating and controlling a working frequency of the delivery pump.   
   
   
       15 . A modular combined refrigerating installation according to  claim 2 , further comprising:
 a sensor for pressure difference between supply and return at the installation side in the cooling medium system to calculate and control a working frequency of the delivery pump.   
   
   
       16 . A modular combined refrigerating installation according to  claim 2 , further comprising:
 a magnetic bearing sensor is mounted at each magnetic bearing of the compressor.   
   
   
       17 . A modular combined refrigerating installation according to  claim 2 , wherein said evaporator is a plate heat exchanger of full liquid evaporation type, which has an inner core and an outer shell, said core is formed by welding a certain number of metal plate of certain geometric shape according to a predetermined rule; said outer shell is a barrel shaped container with a circle or square section; and in said evaporator, there are two or more kinds of medium flowing channels which are isolated from each other.