Device and Method for Maintaining an Air Conditioner

Abstract

A device for maintaining an air conditioner, in particular, for air conditioners using CO 2 or R744 as a coolant. The device has a low-pressure side region (A), which is connectable to a service port on the low-pressure side of the air conditioner via a low-pressure side coupler ( 1 ), and a high-pressure side region (C), which is connectable to a service port on the high-pressure side of the air conditioner via a high-pressure side coupler ( 1 ′). A compressor ( 4 ) is provided between the low-pressure side region (A) and the high-pressure side region (C) and between the compressor ( 4 ) and the high-pressure side region (C) an over-pressure region (B) is provided, which is connected to the high-pressure side region (C) via a throttle device ( 5 ).

1 . A device for maintaining an air conditioner, in particular, for air conditioners using CO 2  or R744 as a coolant, wherein the device has a low-pressure side region, which is connectable to a service port on the low-pressure side of the air conditioner via a low-pressure side coupler, and a high-pressure side region, which is connectable to a service port on the high-pressure side of the air conditioner via a high-pressure side coupler, wherein a compressor is provided between the low-pressure side region and the high-pressure side region, wherein, between the compressor and the high-pressure side region, an over-pressure region is provided, which is connected to the high-pressure side region via a throttle device. 
     
     
         2 . The device according to  claim 1 , wherein the low-pressure side region is connected to a vacuum pump. 
     
     
         3 . The device according to  claim 1 , wherein, starting from the low-pressure side coupler, a circuit fluid connection can be released by valves via
 the low-pressure side region,   the compressor,   the over-pressure region,   the throttle device, and   the high-pressure side region   
       to the high-pressure side coupler. 
     
     
         4 . The device according to  claim 1 , wherein a storage region provides a storage container, which is connectable via valves to the over-pressure region and/or the low-pressure side region. 
     
     
         5 . The device according to  claim 4 , wherein, starting from the low-pressure side coupler, an out-pumping fluid connection can be released by the valves via
 the low-pressure side region,   the compressor, and   the over-pressure region   
       to the storage container. 
     
     
         6 . The device according to  claim 4 , wherein, starting from the storage container, an in-pumping fluid connection can be released by the valves via
 the compressor, and   the over-pressure region, and   the high-pressure side region   
       to the high-pressure side coupler. 
     
     
         7 . The device according to  claim 1 , wherein the drain valves are connected to the low-pressure side region and/or the high-pressure side region. 
     
     
         8 . The device according to  claim 1 , wherein a new oil container is connected to the fluid system via a new oil valve. 
     
     
         9 . The device according to  claim 1 , wherein an oil separator and/or an evaporator and/or a filter dryer is/are provided in the low-pressure side region, and that a liquid separator and/or a gas cooler and/or a flow rate meter is/are provided in the over-pressure region. 
     
     
         10 . The device according to  claim 9 , wherein a switch valve, which is able to reroute the circuit fluid connection to a bypass circumventing the gas cooler, is provided in the over-pressure region between the compressor and the gas cooler. 
     
     
         11 . A method for operating a service device for air conditioners, in particular, for air conditioners using CO 2  or R744 as a coolant, wherein the service device for establishing a circuit is, via a low-pressure side coupler and a high-pressure side coupler, connected to the low-pressure side or the high-pressure side of the air conditioner, and that the method comprises the step to transfer the coolant in the air conditioner from a phase state II within the wet steam curve via a circuit process to a phase state II E  outside of the wet steam curve, wherein the specific enthalpy in phase state II E  has a value which isenthalp lays completely outside of the dry ice region. 
     
     
         12 . The method according to  claim 11 , wherein the circuit process starting from phase state II comprises the following state changes:
 a. essentially isobaric heating of the coolant to outside of the wet steam curve (II=>III);   b. essentially isentropic compression to an over-pressure above the pressure of the initial phase state II and, preferably, above the critical pressure of the coolant (III=>IV);   c. essentially isenthalpic expansion (I=>V); and   d. mixing with the coolant in the air conditioner (V=>II′)   
     
     
         13 . The method according to  claim 11 , featuring, before the step of the circuit process, the following steps:
 evacuating a sealed-off region of the service device that connects at the low-pressure side of the air conditioner and that is separated from said low pressure side by a dosed valve;   opening a fluid connection between the evacuated region of the service device and the fluid system of the air conditioner (expansion I=>I).   
     
     
         14 . The method according to  claim 11 , which, after the circuit process, features the step of pumping the coolant out of the air conditioner into a storage container. 
     
     
         15 . The method according to  claim 11 , wherein old oil is separated and the amount of old oil separated from the air conditioner is determined during the process. 
     
     
         16 . The method according to  claim 11 , which furthermore features the step of evacuating the system after draining and, if applicable, out-pumping the coolant with a vacuum pump. 
     
     
         17 . The method according to  claim 16 , wherein, after removing the coolant and before refilling the air conditioner, new oil is brought into the evacuated fluid system, wherein the amount of new oil is determined on the basis of the amount of separated old oil.