Method for loading refrigerant in an air conditioning system

Abstract

A method for loading refrigerant fluid into an A/C system from an apparatus for recovering and regenerating refrigerant fluid includes a step of hydraulically connecting the apparatus with the A/C system by a high pressure pipe and a low pressure pipe and a step of loading refrigerant fluid present in a storage container of the apparatus into the A/C system.

Claims

1. A method of loading refrigerant into an A/C system from an apparatus for recovering and regenerating the refrigerant, the method comprising the steps of: hydraulically connecting the apparatus with the A/C system through a high pressure pipe and a low pressure pipe; loading the refrigerant present in a storage container of the apparatus into the A/C system; wherein the loading step comprises: measuring an initial amount of refrigerant P.sub.0 present in the storage container; setting a value B of an amount of total refrigerant to be loaded into the A/C system; loading into the A/C system, through the high pressure duct and/or the low pressure duct, an amount of refrigerant in liquid phase equal to B−x, wherein x is a predetermined quantity; calculating a value by the equation B*=B+m, wherein m is a quantity that is positive, negative or null, the absolute value of m being less than the absolute value of B; further loading, for a number i of cycles, where i=1, 2, . . . , n, quantities α.sub.i of refrigerant, comprising the steps of: measuring an actual amount of refrigerant P.sub.i present in the storage container at the i-th cycle; determining by subtraction a value T.sub.i=P.sub.0−P.sub.i, where T.sub.i is an overall amount of refrigerant discharged from the storage container as of the i-th cycle; calculating a quantity α.sub.i by the equation α.sub.i=B*−T.sub.i; loading into the A/C system an amount of refrigerant in liquid phase equal to α.sub.i/2 through the high pressure pipe and/or the low pressure pipe; the further loading ending when α.sub.i becomes less than a predetermined value ε.

2. The method according to claim 1, wherein the quantity m is a function of an average difference of pressure DP.sub.average between a pressure in the storage container and a pressure in the A/C system.

3. The method according to claim 2, wherein the quantity m is a function of the average difference of pressure DP.sub.average according to the following: if DP.sub.average<1 bar, then 8 g<m<12 g; if 1 bar≤DP.sub.average<2 bar, then 1 g<m<5 g; and if DP.sub.average>2 bar, then −4 g<m<0.

4. The method according to claim 1, wherein the quantity m is a function of an average mass flowrate DM.sub.average of refrigerant during the loading of the amount of refrigerant B−x.

5. The method according to claim 4, wherein the quantity m is a function of the average mass flowrate DM.sub.average according to the following: if DM.sub.average<535 g/minute, then 8 g<m<12 g; if 535 g/minute≤DM.sub.average<1070 g/minute, then 1 g<m<5 g; and if DM.sub.average≥1070 g/minute, then −4 g<m<0.

6. The method according to claim 1, wherein 20 g<x<80 g.

7. The method according to claim 1, wherein, before the loading step, the method further comprises a step of sending an amount V.sub.1 of refrigerant in gaseous phase through the low pressure pipe towards the A/C system, in order to push the refrigerant in liquid phase present in the low pressure pipe toward the A/C system.

8. The method according to claim 1, wherein, after the loading step of refrigerant in the liquid phase, the method further comprises a step of sending an amount V.sub.2 of refrigerant in gaseous phase through the high pressure pipe towards the A/C system, in order to push the refrigerant in liquid phase present in the high pressure pipe towards the A/C system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further characteristics and/or advantages of the present invention are clearer with the following description of an exemplary embodiment thereof, exemplifying but not limitative, with reference to the attached drawings in which:

(2) FIG. 1 shows a flowchart of the method for loading refrigerant into an A/C system according to the present invention;

(3) FIG. 2 shows a possible hydraulic connection between a storage container and an A/C system during the loading of refrigerant into the A/C system, according to the method of FIG. 1;

(4) FIG. 3 shows a variant of the method shown in FIG. 1, wherein two further steps are provided of loading refrigerant in gaseous phase into the A/C system;

(5) FIG. 4 shows a possible hydraulic connection between the storage container and the A/C system during the loading of refrigerant according, to the method of FIG. 3;

DESCRIPTION OF A PREFERRED EXEMPLARY EMBODIMENT

(6) With reference to FIGS. 1 and 2, a method for loading refrigerant into an A/C system 200 from an apparatus with a storage container 110 for recovering and regenerating refrigerant 100, according to the present invention, provides a first step (301) of connecting the pipes 101 and 102 to the A/C system 200. In particular, the high pressure pipe 101 is connected to the A/C system 200 at a line where the refrigerant has higher pressure, whereas the low pressure pipe 102 is connected to a line where the refrigerant has lower pressure.

(7) The method then provides a step (302) of setting a value B of a total amount of refrigerant to load from the storage container 110 into the A/C system 200.

(8) A step (303) is then provided where the valve 123a, the valve 133a and/or the valve 133b are open and the refrigerant in liquid phase is drawn by the storage container 110 through a dip tube 111. The refrigerant is loaded into the A/C system 200, through the pipe 103a and one of the pipes 101 and 102, or both. The amount of refrigerant removed from the storage container 110 is determined by a load cell and the valves 133a and 133b are closed when an amount of refrigerant equal to B−x has been removed, where x is a predetermined parameter. Advantageously, the value of x is set between 40 g and 80 g.

(9) Then, a step is provided (305) where a value B* is calculated by the equation B*=B+m, wherein m is a quantity that can be positive, negative or null, the absolute value of m being less than the absolute value of B.

(10) In particular, m can be calculated as a function of one of the following parameters: the average difference of pressure DP.sub.average between the pressure in the storage container 110 and the pressure in the A/C system 200; the average mass flowrate DM.sub.average of refrigerant during the loading of the amount of refrigerant B−x into the A/C system 200.

(11) This way, the value B* can be related to the instantaneous speed at which the refrigerant is loaded into the A/C system. This reduces the uncertainties in managing the refrigerant to be loaded, since the higher the speed, then the larger the uncertainty is in measuring the amount of refrigerant loaded and, therefore, the lower the value B* has to be.

(12) In a first embodiment, in order to compute B*, a step is provided (304) before the step (305) where the average pressure difference DP.sub.average between the pressure in the storage container 110 and the pressure in the A/C system 200 is calculated.

(13) In particular, m, and therefore B*, is a function of DP.sub.average according to the following law: if DP.sub.average<1 bar, then 8 g<m<12 g; if 1 bar≤DP.sub.average<2 bar, then 1 g<m<5 g; and if DP.sub.average≥2 bar, then −4 g<m<0.

(14) Alternatively, in a second embodiment, it is possible to calculate m as a function of the average mass flowrate DM.sub.average of refrigerant during the loading of the amount of refrigerant B−x into the A/C system 200.

(15) In this case, m is a function of DM.sub.average according to the following law: if DM.sub.average<535 g/minute, then 8 g<m<12 g; if 535 g/minute≤DM.sub.average<1070 g/minute, then 1 g<m<5 g; and if DM.sub.average≥1070 g/minute, then −4 g<m<0.

(16) A step of further loading, for a number i of cycles, where i=1, 2, . . . , n, quantities α.sub.i of refrigerant, comprises: measuring the actual amount of refrigerant P.sub.i present in the storage container 110 at the i-th cycle and determining by subtraction a value T.sub.i=P.sub.0−P.sub.i, where T.sub.i is the overall amount of refrigerant discharged from the storage container 110 as of the i-th cycle (306); calculating a quantity α.sub.i by the equation α.sub.i=B*−T.sub.i (307); loading into the A/C system 200 an amount of refrigerant in liquid phase equal to α.sub.i/2 through the high pressure pipe 101 and/or through the low pressure pipe 102 (308).

(17) The further loading goes on until α.sub.i is higher than a predetermined value ε, for example, between 2 g and 10 g.

(18) This way, the refrigerant loaded into the A/C system 200 is monitored at each repeating cycle, to ensure staying within the tolerances required by regulations.

(19) With reference to FIGS. 3 and 4, an exemplary implementation of the method above described provides the introduction of two steps of sending refrigerant in vapor phase to push the refrigerant in liquid phase present in the pipes 101 and 102 towards the A/C system 200.

(20) In particular, a first step (309), before the further loading step, provides the opening of the valves 123b and 133b. This way, through an opening 112 which is located in the upper part of the container 110, an amount V.sub.1 of refrigerant in gaseous phase comes out because of the pressure difference. This amount of refrigerant V.sub.1 crosses the pipes 103b and 103c to reach the low pressure pipe 102, which is emptied of the liquid phase refrigerant present. For example, the amount V.sub.1 can be about 10 g.

(21) During the repeating step, the valves 123b and 133b are closed and the valves 123a and 133a are open, in such a way that the refrigerant in liquid phase arrives at the A/C system 200 through the pipes 103a and 103c and the high pressure pipe 101.

(22) At the end of the repeating step, there is then a further step (310) in which the valve 123a is closed and the valve 123b is opened that makes it possible for an amount V.sub.2 of refrigerant in gaseous phase to cross the pipes 103b and 103c and reach the high pressure pipe 101, which is emptied by the refrigerant accumulated during the repeating step.

(23) If the valves 133a and 133b are manual, the steps (309, 310) are grouped in a single step that provides the opening of the valves 133a, 133b and 123b, allowing an amount V.sub.3 of refrigerant in gaseous phase to cross the pipes 103b and 103c and reach the pipes of high and low pressure 101 and 102, which are emptied of the liquid refrigerant accumulated during the repeating step.

(24) The foregoing description some exemplary specific embodiments will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt in various applications the specific exemplary embodiments without further research and without parting from the invention, and, accordingly, it is meant that such adaptations and modifications will have to be considered as equivalent to the specific embodiments. The means and the materials to realize the different functions described herein could have a different nature without, for this reason, departing from the field of the invention, it is to be understood that the phraseology or terminology that is employed herein is for the purpose of description and not of limitation.