METHOD FOR LOADING REFRIGERANT FLUID IN AN AIR CONDITIONING SYSTEM

Abstract

A method for loading refrigerant fluid in a A/C system from an apparatus for recovering and regenerating refrigerant fluid comprises a step of hydraulically connecting the apparatus with the A/C system by a high pressure duct and a low pressure duct and a step of loading refrigerant fluid present into a storage container of the apparatus into the A/C system. The loading step comprises the steps of setting a value Q of total amount of refrigerant to load, loading in the A/C system an amount of refrigerant in liquid phase equal to Qx, changing value Q with a value Q depending to the loading speed of the refrigerant in the A/C system. Furthermore, there is a step of iterating for a number i of cycles the steps of measuring the amount of refrigerant fluid contained in the storage container obtaining a value T.sub.i of the amount of fluid discharged to the i-th cycle, computing an amount .sub.i=QT.sub.i of refrigerant still to load to the i-th cycle and loading in the A/C system an amount of refrigerant in liquid phase equal to .sub.i/2. The step of iterating ends when .sub.i becomes less than a predetermined value .

Claims

1. A method for loading refrigerant fluid in a A/C system from an apparatus for recovering and regenerating refrigerant fluid, said method comprising the steps of: hydraulically connecting said apparatus with said A/C system through a high pressure duct and a low pressure duct; loading in said A/C system refrigerant fluid present into a storage container of said apparatus; characterized in that said loading step comprises the steps of: setting a value Q of the amount of total refrigerant to load in said A/C system; loading in said A/C system, through said high pressure duct and/or said low pressure duct, an amount of refrigerant in liquid phase equal to Qx; changing said value Q of the amount of total refrigerant to load with a value Q dependent to the speed of loading said refrigerant in said A/C system; iterating, for a number i of cycles, of the steps of: measuring the amount of refrigerant fluid contained in said storage container obtaining a value T.sub.i of the amount of fluid discharged from said storage container at the i-th cycle; computing an amount .sub.i=QT.sub.i of refrigerant still to load at the i-th cycle; loading in said A/C system an amount of refrigerant in liquid phase equal to .sub.i/2 through said high pressure duct and/or said low pressure duct; said step of iterating ending when .sub.i becomes less than a predetermined value .

2. Method for loading refrigerant fluid in a A/C system from an apparatus for recovering and regenerating refrigerant fluid, according to claim 1, wherein Q=f(Q,DP.sub.average) is a value according to Q and to the average difference of pressure DP.sub.average between the pressure in said storage container and the pressure in said A/C system.

3. Method for loading refrigerant fluid in a A/C system from an apparatus for recovering and regenerating refrigerant fluid, according to claim 2, wherein said value Q depends to said average difference of pressure DP.sub.average according to the following law:
DP.sub.average<1 bar.Math.Q=Q+m.sub.1
1 barDP.sub.average<2 bar.Math.Q=Q+m.sub.2
DP.sub.average>2 bar.Math.Q=Q+m.sub.3

4. Method for loading refrigerant fluid in a A/C system from an apparatus for recovering and regenerating refrigerant fluid, according to claim 1, wherein Q=f(Q,DM.sub.average) is a value dependent to Q and to the average mass flowrate DM.sub.average of refrigerant during the loading of said amount of refrigerant Qx.

5. Method for loading refrigerant fluid in a A/C system from an apparatus for recovering and regenerating refrigerant fluid, according to claim 4, wherein said value Q depends to said average mass flowrate DM.sub.average according to the following law: $-.Math.{\mathrm{DM}}_{\mathrm{average}}<\frac{535.Math..Math.g}{\mathrm{minute}}.Math.Q^{}=Q+m_1.Math.-.Math.\frac{535.Math..Math.g}{\mathrm{minuto}}{\mathrm{DM}}_{\mathrm{average}}<\frac{1070.Math..Math.g}{\mathrm{minute}}.Math..Math.\mathrm{bar}.Math.Q^{}=Q+m_2.Math.-.Math.{\mathrm{DM}}_{\mathrm{average}}\frac{1070.Math..Math.g}{\mathrm{minute}}.Math.Q^{}=Q+m_3$

6. Method for loading refrigerant fluid in a A/C system from an apparatus for recovering and regenerating refrigerant fluid, according to claim 3, wherein 8 g<m.sub.1<12 g, 1 g<m.sub.2<5 g, 4 g<m.sub.3<0.

7. Method for loading refrigerant fluid in a A/C system from an apparatus for recovering and regenerating refrigerant fluid, according to claim 1, wherein 20 g<x<80 g.

8. Method for loading refrigerant fluid in a A/C system from an apparatus for recovering and regenerating refrigerant fluid, according to claim 1, wherein, upstream of said step of iterating, a step is provided of sending towards said A/C system an amount V.sub.1 of refrigerant fluid in gaseous phase through said low pressure duct, in order to push towards said plant the refrigerant in liquid phase present in said low pressure duct.

9. Method for loading refrigerant fluid in a A/C system from an apparatus for recovering and regenerating refrigerant fluid, according to claim 1, wherein, downstream of said loading step of refrigerant fluid in liquid phase, a step is provided of sending towards said A/C system an amount V.sub.2 of refrigerant fluid in gaseous phase through said high pressure duct, in order to push towards said plant the refrigerant in liquid phase present in said high pressure duct.

10. Method for loading refrigerant fluid in a A/C system from an apparatus for recovering and regenerating refrigerant fluid, according to claim 3, wherein 8 g<m.sub.1<12 g, 1 g<m.sub.2<5 g, 4 g<m.sub.3<0.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Further characteristic and/or advantages of the present invention are brighter with the following description of an exemplary embodiment thereof, exemplifying but not limitative, with reference to the attached drawings in which:

[0040] FIG. 1 shows a flowchart of the method for loading refrigerant fluid in a A/C system according to the present invention;

[0041] FIG. 2 shows a possible hydraulic connection between storage container and A/C system during the loading of refrigerant fluid, according to the method of FIG. 1;

[0042] FIG. 3 shows a variant of the method shown in FIG. 1, wherein two further steps are provided of loading refrigerant fluid in gaseous phase;

[0043] FIG. 4 shows a possible hydraulic connection between storage container and A/C system during the loading of refrigerant fluid according, to the method of FIG. 3;

DESCRIPTION OF A PREFERRED EXEMPLARY EMBODIMENT

[0044] With reference to FIGS. 1 and 2, the method for loading refrigerant fluid in an A/C system 200 from an apparatus for recovering and regenerating refrigerant fluid 100, according to the present invention, provides a first step (301) of connecting the ducts 101 and 102 to the A/C system 200. In particular, the high pressure duct 101 is connected to the plant 200 at a line where the refrigerant has higher pressure, whereas the low pressure duct 102 is connected to a line where the refrigerant has lower pressure.

[0045] The method provides then a step (302) of setting a value Q of total amount of refrigerant to load in the A/C system.

[0046] A step (303) is then provided where the valve 123a, the valve 133a and/or the valve 133b are open and the refrigerant fluid in liquid phase is drawn by the storage container 110 through a dip tube 111. The refrigerant fluid, through the duct 103a and one of the ducts 101 and 102, or both, is loaded in the A/C system 200. 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 Qx has been removed, where x is a predetermined parameter. Advantageously, value of x is set between 40 g and 80 g.

[0047] Then, a step is provided (305) where value of Q initially calculated is replaced by a value Q dependent to the loading speed of the refrigerant in the A/C system 200. In particular, the higher the speed the larger the uncertainty in measuring the amount of fluid loaded and therefore lower has to be value of Q.

[0048] In order to compute Q a step is provided (304) upstream of the step (305) where it is calculated the average pressure difference DP.sub.average between the pressure in the storage container 110 and the pressure in the A/C system 200. This way, it is possible to correlate the amount Q to the speed with which the refrigerant is loaded in the plant 200, since higher is DP.sub.average higher is the loading speed of the refrigerant.

[0049] In particular, Q depends to DP.sub.average according to the following law:

DP.sub.average<1 bar.Math.Q=Q+m.sub.1

1 bar<DP.sub.average<2 bar.Math.Q=Q+m.sub.2

DP.sub.average>2 bar.Math.Q=Q+m.sub.3

[0050] where, for example, 8 g<m.sub.1<12 g, 1 g<m.sub.2<5 g, 4 g<m.sub.3<0. As described, higher is value of DP.sub.average and lower is value of Q, since the loading speed, and then the uncertainty, is higher.

[0051] Alternatively, it is possible to calculate Q on the basis of the average mass flowrate DM.sub.average of refrigerant during the loading of the amount of refrigerant Qx.

[0052] In this case, Q depends to DM.sub.average according to the following law:

[00002]$-.Math.{\mathrm{DM}}_{\mathrm{average}}<\frac{535.Math..Math.g}{\mathrm{minute}}.Math.Q^{}=Q+m_1.Math.-.Math.\frac{535.Math..Math.g}{\mathrm{minuto}}{\mathrm{DM}}_{\mathrm{average}}<\frac{1070.Math..Math.g}{\mathrm{minute}}.Math..Math.\mathrm{bar}.Math.Q^{}=Q+m_2.Math.-.Math.{\mathrm{DM}}_{\mathrm{average}}\frac{1070.Math..Math.g}{\mathrm{minute}}.Math.Q^{}=Q+m_3$

[0053] Similarly to what said above, higher is value of DM.sub.average and lower is value of Q because the loading speed is higher.

[0054] It begins then a step of iterating, for a number i of cycles, the steps of: [0055] measuring the amount of refrigerant fluid contained in the storage container 110 obtaining a value T.sub.i of the amount of fluid discharged from the storage container 110 at the i-th cycle (306); [0056] computing an amount .sub.i=QT.sub.i of refrigerant still to load at the i-th cycle (307); [0057] loading in the A/C system 200 an amount of refrigerant in liquid phase equal to .sub.i/2 through the high pressure duct 101 and/or through the low pressure duct 102 (308).

[0058] The iteration goes on until .sub.i is higher than a predetermined value , for example comprised between 2 g and 10 g.

[0059] This way, the refrigerant loaded is monitored at each iterative cycle, ensuring to stay within the tolerances required by regulations.

[0060] 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 vapour phase arranged to push towards the plant 200 the refrigerant in liquid phase present in the duct 101 and 102.

[0061] In particular, a first step (309), upstream of the iterating 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 ducts 103b and 103c up to reaching the low pressure duct 102, which is emptied of the liquid phase refrigerant present. For example, the amount V.sub.1 can be about 10 g.

[0062] During the iterating 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 to the plant 200 through the ducts 103a and 103c and the high pressure duct 101.

[0063] At the end of the iterating step, there is then a further step (310) in which the valve 123a is closed and the it is opened the valve 123b that makes it possible to an amount V.sub.2 of refrigerant in gaseous phase to cross the ducts 103b and 103c up to reaching the high pressure duct 101, which is emptied by the refrigerant accumulated during the iterating step.

[0064] 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 ducts 103b and 103c up to reaching the ducts of high and low pressure 101 and 102, which are emptied from the liquid refrigerant accumulated during the iterating step.

[0065] 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 realise 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.