Cooling system with adjustable internal heat exchanger

Abstract

A cooling system includes: connected in a loop by fluid lines and in succession, a compressor, a condenser, an expansion valve, and an evaporator; and an internal heat exchanger having a first conduit in heat exchanging contact with a second conduit, the first conduit being part of the fluid line between the condenser and the expansion valve and the second conduit being part of the fluid line between the evaporator and the compressor. A bypass fluid line is arranged between two ends of the first conduit of the internal heat exchanger or extends between one of the two ends of the first conduit and a position along a length of the first conduit.

1 . A cooling system, comprising:
 connected in a loop by fluid lines and in succession, a compressor, a condenser, an expansion valve and an evaporator; and   an internal heat exchanger having a first conduit in heat exchanging contact with a second conduit, the first conduit being part of the fluid line between the condenser and the expansion valve and the second conduit being part of the fluid line between the evaporator and the compressor,   wherein a bypass fluid line is arranged between two ends of the first conduit of the internal heat exchanger or extends between one of the two ends of the first conduit and a position along a length of the first conduit.   
     
     
         2 . The cooling system according to  claim 1 , further comprising a controllable valve arranged in the bypass fluid line and being configured to control an amount of fluid flowing through the bypass fluid line. 
     
     
         3 . The cooling system according to  claim 2 , wherein the controllable valve comprises a three way valve and is arranged either at a junction of the bypass fluid line and the fluid line between the condenser and the internal heat exchanger or at a junction of the bypass fluid line and the fluid line between the internal heat exchanger and the expansion valve. 
     
     
         4 . The cooling system according to  claim 2 , further comprising a temperature sensor arranged in the fluid line between the compressor and the first conduit of the internal heat exchanger and being configured to control the controllable valve based on a temperature measured by the temperature sensor. 
     
     
         5 . The cooling system according to  claim 2 , further comprising a temperature sensor arranged in the fluid line between the second conduit of the internal heat exchanger and the compressor, and a control device connected to the temperature sensor and the controllable valve, the control device being configured to control the controllable valve based on a temperature measured by the temperature sensor. 
     
     
         6 . The cooling system according to  claim 2 , further comprising a pressure sensor arranged in the fluid line between the second conduit of the internal heat exchanger and the compressor. 
     
     
         7 . The cooling system according to  claim 4 , wherein the temperature sensor arranged in the fluid line between the compressor and the first conduit of the internal heat exchanger is arranged between the compressor and the condenser. 
     
     
         8 . The cooling system according to  claim 1 , wherein the bypass fluid line contains only a single controllable valve and/or wherein an amount of fluid flowing through the bypass fluid line is controlled only via a single controllable valve. 
     
     
         9 . The cooling system according to  claim 2 , wherein the controllable valve comprises a proportional valve. 
     
     
         10 . The cooling system according to  claim 1 , wherein a smallest diameter of the bypass fluid line is larger than a largest diameter of the fluid line, including the first conduit, between an inlet junction and an outlet junction, or
 wherein the smallest diameter of the fluid line, including the first conduit, between the inlet junction and the outlet junction is larger than a largest diameter of the bypass fluid line.   
     
     
         11 . The cooling system according to  claim 1 , wherein the condenser is free of a branch-off,
 wherein the first conduit of the internal heat exchanger and the expansion valve are connected solely via the single fluid line, and   wherein the fluid line between the condenser and the first conduit of the internal heat exchanger is permanently open.   
     
     
         12 . The cooling system according to  claim 2 , wherein the controllable valve is integrated in a connecting flange of the internal heat exchanger. 
     
     
         13 . The cooling system according to  claim 1 , wherein the cooling system is filled with R134a or HFO1234yf as refrigerant. 
     
     
         14 . A method for controlling the cooling system according to  claim 1 , comprising the steps of:
 measuring, a fluid temperature of a refrigerant of the cooling system using a temperature sensor comprising a fluid line between the compressor and the condenser; and   controlling, proportionally to the fluid temperature measured by the temperature sensor, a mass flow of fluid passing through the internal heat exchanger by automatically actuating a controllable valve that is arranged to control an amount of fluid flowing through the bypass fluid line.   
     
     
         15 . The method according to  claim 14 , further comprising the steps of:
 measuring, the fluid temperature and a pressure of the refrigerant of the cooling system using a further temperature sensor and a pressure sensor,. both of which comprise a fluid line between the second conduit of the internal heat exchanger and the compressor, the further temperature sensor and the pressure sensor being located close to or directly at an inlet side of the compressor;   continuously determining or calculating, based on measurements of the further temperature sensor and a pressure sensor and using a controller, an overheating of the fluid;   proportionally increasing the fluid mass flow through the bypass fluid line if the overheating of the fluid exceeds or is about to exceed a predefined max overheating threshold or overheating range; and/or   proportionally reducing the fluid mass flow through the bypass fluid line close or equal to zero if the overheating of the fluid falls or is about to fall below the predefined max overheating threshold or overheating range; and/or   keeping the mass flow through the bypass fluid line steady, close or equal to zero if the continuously determined or calculated overheating remains on the predefined overheating threshold or within the predefined overheating range.   
     
     
         16 . The cooling system according to  claim 7 , wherein the temperature sensor arranged in the fluid line between the compressor and the first conduit of the internal heat exchanger is arranged between the compressor and the condenser directly after or close to the compressor. 
     
     
         17 . The cooling system according to  claim 9 , wherein the proportional valve comprises a proportional two-way valve. 
     
     
         18 . The method according to  claim 14 , wherein the measuring is continuous. 
     
     
         19 . The method according to  claim 14 , wherein the temperature sensor is located close to or directly at an outlet side of the compressor. 
     
     
         20 . The method according to  claim 15 , wherein the measuring is continuous.