ITMC20100074A1 - LIQUID RECEIVER-SEPARATOR FOR REFRIGERANT CYCLE REVERSAL UNIT. - Google Patents

Description

"LIQUID RECEIVER-SEPARATOR FOR REVERSE REFRIGERATOR CYCLE UNIT"

TEXT OF THE DESCRIPTION

The present patent application for industrial invention relates to a liquid separator receiver for refrigeration cycle inversion units for heat pump operation.

Heat pumps on air conditioning systems are widely available on the market. Depending on the type of use of the heat pump, there are four configurations, they are:

- Air / air configuration, with finned pack exchangers commonly called coils, both on the use air side (environment) and on the disposable air side (external). These coils, depending on the seasonal operating mode of the machine, take on different tasks, i.e. condenser when they have the task of condensing the refrigerant gas that passes through the coil, dissipating the heat through air, or evaporator when they have the task of evaporating the refrigerant liquid running through the coil, absorbing heat from the air. In the reverse cycle heat pump, the heat exchangers on the disposable side and on the use side reverse their tasks. More precisely, when the cooling operation mode is requested, the finned pack coil on the disposable side works as a condenser, while the one on the user side works as an evaporator. In heating mode, the disposable coil works as an evaporator, while the user side acts as a condenser. Given the diversity of dimensions, temperatures and pressures, the refrigerant content inside the coils varies according to the operating mode, so it is necessary to introduce a liquid receiver in the refrigeration circuit which will have the task of compensating these differences in refrigerant charge in order to have a correct operation.

- Air / water configuration, with the finned pack coil on the disposable air side (external), while on the use there is a water exchanger. This coil, depending on the seasonal operating mode of the machine, takes on a different task, ie condenser when it is required to cool the water used and evaporator when there is a request to heat the water, vice versa for the water exchanger. In this particular version, the differences in refrigerant content inside the exchangers depending on the operating mode are greater for the same cooling capacity, so the receiver will be larger than in the previous configuration.

- Water / air configuration, with the finned pack coil only on the air use side (environment), while on the disposable side there is a water exchanger. This coil, depending on the seasonal operating mode of the machine, takes on a different task, ie evaporator when it is required to cool the environment and condenser when it is required to heat the environment, vice versa for the water exchanger. Also in this case there are differences regarding the refrigerant contents inside the exchangers depending on the operating mode, so the liquid receiver will be needed to compensate for the refrigerant charge. But in this specific case the receiver, to do its job, must be full in cooling mode and empty in heating mode, therefore with the function reversed with respect to the two previous cases.

- Water / water configuration, are not taken into consideration as they do not normally use liquid receivers, given the equality of the exchangers in question.

In addition to the liquid receiver in the air / air and air / water spots, there are gas separators, which have the task of avoiding any backflow of liquid in suction to the compressor, during the defrosting phases or in the presence of frost in the coils. external finned pack, during the heating mode.

In Figs. 1, 2, 3, and 4 show the hydraulic circuits respectively of the four illustrated configurations, where some components are shown which are:

- Compressor (1);

- Four-way valve (2) for cycle inversion;

- Heat exchanger (3) placed on the disposable side (condenser in cooling, evaporator in heating) - Check valve (4) for exchanger liquid outlet on the disposable side;

- Liquid receiver (5);

- Lamination or thermostatic valve (6) on the user side;

- Heat exchanger (7) on the user side (evaporator in cooling, condenser in heating)

- Gas separator (8);

- Check valve (9) for liquid outlet from the exchanger (7) on the user side; And

- Lamination or thermostatic valve (10) on the disposable side.

Summer Operation:

the refrigerant gas compressed by the compressor (1) is directed by the four-way valve (2) to the disposable side exchanger (3) (which acts as a condenser) where it rejects the heat and then heats; the refrigerant liquid condensed through the check valve (4) is deposited inside the receiver (5), then the liquid drawn from the bottom expands in the thermostatically controlled lamination valve (6); the cold fluid exiting the lamination valve goes to the user side exchanger (7) (which acts as an evaporator), where it subtracts heat and then cools; then the refrigerant gas enters the gas separator (8) so that unlikely traces of liquid can be retained by it, thanks to the outlet on the upper part, the gas then returns to the four-way valve (2) which directs it towards the compressor (1).

Winter Operation:

the refrigerant gas compressed by the compressor (1) is directed by the four-way valve (2) to the user-side exchanger (7) (which acts as a condenser) where it supplies heat and then heats; the refrigerant liquid condensed through the check valve (9) is deposited inside the receiver (5), then the liquid drawn from the bottom expands in the thermostatically controlled lamination valve (10); the cold fluid exiting the lamination valve goes to the heat exchanger on the disposable side (3) (which acts as an evaporator) where it subtracts heat and then cools; then the refrigerant gas enters the gas separator (8) so that probable traces of liquid can be retained by it, thanks to the outlet on the upper part, the gas then returns to the four-way valve (2) which directs it towards the compressor (1).

The liquid receiver (5) is of considerable importance as regards the yield of the unit with reverse refrigeration cycle for heat pump operation, because it must absorb the differences in the refrigerant charge requirements. In practice, in order to have maximum energy efficiency, the lamination or thermostatic valve must be constantly fed by liquid only, so that there is a total change in the state of the volume of the refrigerant compressed by the compressor.

In addition to this, the condenser must not be flooded, as if this happened there would be a reduction in the exchange surface of the condenser, with a consequent increase in the condensation pressure and therefore more work to be done by the compressor or greater electrical absorption. In practice, the receiver must be sized in order to contain the diversity of refrigerant present in the two exchangers, of different volumes and pressures, between the two operating modes. The liquid receivers are nothing more than vessels used for operation under pressure, depending on the type of refrigerant gas, made with iron pipes with welded bottoms, with two pipes, one of which is the liquid inlet and the other of exit fishing from the bottom. They can be of different sizes depending on the quantity of refrigerant that must be compensated for in the refrigeration circuit, and they can be of the vertical type (Fig. 5) or horizontal (Fig. 6).

The gas separator (8) also has its importance, as it must prevent the return of liquid to the compressor (1), as the latter could be damaged. Liquid returns can occur in machines with a finned pack exchanger also called battery, on the disposable side, during heat pump operation; this is because in the presence of low temperatures frost is formed in the external coil, which prevents the correct evaporation of the refrigerant liquid. The liquid returns mainly occur during the defrosting cycles necessary to remove the frost present on the finned pack, therefore the gas separators are indispensable in the air / air and air / water units with reverse refrigeration cycle for heat pump operation . Gas separators are nothing more than vessels used for operation under pressure, depending on the type of refrigerant gas, made with iron pipes with welded bottoms, with two pipes, one of which is the gas inlet, which can stop on the top of the separator or reach the bottom. The gas outlet pipe is a little more particular as it forms a kind of U inside the gun, so that the lower part of this U is almost lying on the bottom of the separator, to allow the oil present in the refrigerant to return to the compressor due to the Venturi effect, through a calibrated hole made at the lower end of the same U. They can be of different sizes depending on the quantity of refrigerant liquid that must be retained to prevent it from reaching the compressor.

These separators are normally made in the vertical form as you can see in Fig. 7 and include a suction pipe (gas outlet) (80) inside. With reference to Figs. 8 and 9, the gas outlet suction pipe (80) has a U shape and includes a calibrated hole (81) on a lower portion of the â € œUâ €. The calibrated hole (81) is used to return the oil to the compressor (1).

As for the operation of the separator (8), if the separator (8) is sized correctly, you can be sure that it does its job.

Otherwise, the receiver (5), even if dimensioned correctly, cannot have a predetermined functioning of its full or empty state. In fact, the liquid or gaseous state of the refrigerant inside will be determined solely by the pressure of the refrigerant and the temperature in which the receiver is located.

More precisely, if the temperature of the receiver (5) is lower than the condensation temperature of the refrigerant, there will certainly be a large quantity of liquid inside it, while if the temperature of the receiver is higher than the condensation temperature, there will be a lot of liquid inside it. it will be a small amount of coolant.

Thanks to this principle, many manufacturers insert the receivers (5) inside the ventilation compartment of the disposable side batteries (3), so that the same receiver can heat up during summer operation, making the refrigerant liquid contained in the inside. On the other hand, in winter operation the receiver itself would be cooled, thus retaining a greater quantity of liquid inside it. This system is partially effective, but in any case it fails to guarantee that the receiver is almost full of liquid in winter and almost empty in summer, because the exchange between the receiver and the air that has passed through the disposable side coil is reduced and therefore not able to keep the receiver at the temperatures necessary for it to perform optimal operation.

In addition to this there is another problem during winter operation. When a defrosting cycle is to be carried out, a total quantity of refrigerant is not available to perform defrosting effectively and quickly, as a certain quantity of refrigerant liquid would be retained inside the receiver, compromising the ™ full efficiency of the refrigeration cycle inversion unit during heat pump operation.

In this regard, some manufacturers have created a variant on the classic circuitry. Fig. 10 shows the circulation of an air / water configuration. As far as operation is concerned, it is easy to understand that the receiver (5), located in a different point compared to the previous versions, will be almost full of refrigerant in the winter operating mode, given its connection on the liquid outlet from the exchanger ( 7), while it will be devoid of liquid content in summer operating mode, since the liquid is sucked by the compressor (1), through the four-way valve (2) and the exchanger (7).

In this way, the liquid receiver (5) has an apparently regular operation, empty of liquid during summer operation and almost full of liquid during winter.

In addition to this, the defrosting cycle is fast and effective, as the liquid is sucked immediately in the instant that the four-way valve (2) is inverted, through the exchanger (7). However, this operation at the same time represents a risk for the compressor (1), because all the liquid present in the receiver (8) does not pass through the lamination valve (6) and floods the exchanger (7). With good probability some parts of liquid reach the compressor (1), without being retained by the gas separator (8), given the consistent quantity and speed, causing damage to the compressor (1) in the long run.

The purpose of the present invention is to eliminate the drawbacks of the known art, by providing a liquid separator receiver for refrigeration cycle inversion units for heat pump operation which allows to ensure the maximum compensation efficiency of the refrigerant liquid between the two modes of operation, summer and winter and at the same time make the refrigerant liquid quickly available for the defrost cycle, in order to obtain a fast and efficient receiver-separator.

Another purpose of the present invention is to provide such a liquid separator receiver that is versatile, economical and simple to make and install, but above all that allows the heat pump refrigeration unit to obtain a high energy efficiency class. .

These objects are achieved in accordance with the invention, with the characteristics listed in the attached independent claim 1.

Advantageous embodiments appear from the dependent claims.

The receiver unit - liquid separator for refrigeration cycle inversion units for heat pump operation, according to the invention, includes:

- a first container acting as a coolant liquid receiver; And

- a second container acting as a gas separator from the refrigerant liquid.

The first container is arranged coaxially within said second container.

The advantages of the receiver - liquid separator according to the invention are evident in which the quantity of refrigerant liquid present in the internal container varies, due to the temperature variation of the internal container itself, due to the subsidence or absorption of heat, carried out by the gas in transit on the external container, through the common exchange surface.

In practice, two different conditions occur:

- when in the external part of the receiver - liquid separator transits hot gas the heat is transferred to the internal part where the receiver is inserted and thanks to the heating of the receiver, the liquid inside it is made almost all available making the receiver almost empty of liquid refrigerant

- when in the external part of the receiver â € “liquid separator transits cold gas, therefore the external container acts as a gas separator, the heat is absorbed by the internal part where the receiver is inserted and thanks to the cooling of the receiver it is retained more liquid possible by making the receiver nearly full of refrigerant in liquid form.

Further characteristics of the invention will become clearer from the detailed description that follows, referring to its purely exemplary and therefore non-limiting embodiments, illustrated in the attached drawings, in which:

- Fig. 1 is a refrigeration circuit of an air / air unit with reverse cycle for heat pump operation, with receiver and separator according to the known technique;

- Fig. 2 is a refrigeration circuit of a reverse cycle air / water unit for heat pump operation, with receiver and separator according to the known technique;

- Fig. 3 is a refrigeration circuit of a reverse cycle water / air unit for heat pump operation, with receiver and separator according to the known technique;

- Fig. 4 is a refrigeration circuit of a reverse cycle water / water unit for heat pump operation;

- Fig. 5 is a perspective view of a vertical liquid receiver, for a refrigeration cycle inversion unit for heat pump operation, according to the known art;

- Fig. 6 is a perspective view of a horizontal liquid receiver, for a refrigeration cycle inversion unit for heat pump operation, according to the known art;

- Fig. 7 is a perspective view of a vertical gas separator, for a refrigeration cycle inversion unit for heat pump operation, according to the known art;

- Fig. 8 is a perspective view of a vertical gas separator with a view of gas inlet and outlet pipes on the outside, for a refrigeration cycle inversion unit for heat pump operation, according to the known technique ;

- Fig. 9 is a perspective view from below of a vertical gas separator with a view of gas inlet and outlet pipes outside, for a refrigeration cycle inversion unit for heat pump operation, according to prior art;

- Fig. 10 is a variant of the refrigeration circuit of an air / water unit with reverse cycle for heat pump operation, according to the known technique;

- Fig. 11 is a perspective view of the vertical liquid separator-receiver for refrigeration cycle inversion units, according to the invention;

- Fig. 12 is an exploded view of the high separator receiver of Fig. 11;

- Fig. 13 is an exploded view from below of the separator receiver of Fig. 11;

- Fig. 14 is a perspective view of the horizontal liquid separator-receiver for refrigeration cycle inversion units, according to the invention;

- Fig. 15 is a perspective exploded view of the receiver - horizontal liquid separator of Fig. 14;

- Fig. 16 is a refrigeration circuit of a reverse cycle air / air unit for heat pump operation, with liquid receiver - separator according to the invention;

- Fig. 17 is a refrigeration circuit of an inversion cycle air / water unit for heat pump operation, with liquid receiver - separator according to the invention; And

- Fig. 18 is a refrigeration circuit of a reverse cycle water / air unit for heat pump operation, with liquid receiver - separator according to the invention.

With the aid of Figs. 11 to 13 a liquid separator - liquid separator for refrigeration cycle inversion units is described, according to the invention, arranged in a vertical configuration and indicated as a whole with the reference number ( 100).

The liquid separator receiver (100) comprises an internal metal container (101) arranged coaxially within an external metal container (105). The internal container (101) has the function of liquid receiver; while the external container (105) has the function of a gas separator.

The internal container (101) is suitable for operation under pressure with the task of liquid receiver. The inner container (101) has a substantially cylindrical shape and comprises a vertical tubular body (110), an upper wall (111) and a lower wall (112). The upper (111) and lower (112) walls are welded to the tubular body (110) by welding (S).

The upper wall (111) has two holes (115) for the passage of an outlet pipe (102) and an inlet pipe (103) for the outlet and inlet of a liquid (L ).

The outlet tube (102) draws from the bottom of the inner container (101). The inlet pipe (103) can either reach the bottom of the container or remain separate from the bottom. If you do not want to create distinctions between inlet and outlet, to facilitate installation without making mistakes, the two pipes (102, 103) can be of equal length.

In the lower wall (103) of the receiver a fixing support (114) is welded to support the whole receiver-liquid separator unit (100).

Optionally, another tube (104) can be inserted into the internal container (101) which has two ends connected respectively to the upper part and to the lower part of the container (101). The tube (104) extends outside the external container (105), and houses two liquid level sight glasses (140, 141) spaced vertically from each other. The first level warning light (140) signals a high level of coolant within the container (101). The second sight glass (141) is located lower than the first sight glass (140) and signals a low level of liquid inside the container (101). In this motion, the user can check the refrigerant charge of the refrigeration circuit and the correct operation of the receiver container (101) according to the seasonal function.

The external metal container (105) is suitable for operation under pressure, with the task of a gas separator, in the event that the fresh suction gas of the compressor passes through it. This external container (105) has a substantially toroidal shape and comprises a vertical tubular body (150), with a height lower than that of the tubular body (110) of the receiver, so as to leave a lower portion (181) of the receiver uncovered ( 101).

In this way, when the almost empty receiver function is requested, the little refrigerant liquid contained in the lower portion (181) of the receiver (101) does not undergo an excessive heat exchange with the hot gas in transit in the external container (105). Therefore the liquid itself coming out of the receiver can correctly feed the lamination valve.

The external diameter of the tubular body (150) is larger than that of the receiver body (110), so as to create a toroidal volume, between the two tubular bodies, suitable for the operation of the gas separator (105).

An upper wall (151) and a lower wall (152) are welded to the tubular body (150) by welding (S). Both the upper and lower walls (150, 151) are perforated centrally to house the receiver (101). The receiver (1) is welded to the upper and lower walls (151, 152) of the separator, by means of respective welds (S).

The upper wall (151) of the separator has two peripheral holes (155) for the insertion of two pipes (106, 107) for the passage of gas (Gf, Gc). The first tube (106) is a straight vertical tube that reaches the bottom of the separator (105). The pipe (106) is used for the inlet of fresh gas (Gf) and the outlet of hot gas (Gc).

The second tube (107) has a substantially "U" shape and includes two vertical sections (170, 171) connected to each other by a connecting section (172) with a curved shape on a horizontal plane. The first vertical section (170) has an end that comes out of the separator (105). Instead the second vertical section (171) has an extremity (173) that fishes in the upper part of the separator (105). The â € œUâ € duct (107) is used for the exit of fresh gas (Gf) in the absence of liquid parts, for the suction of the compressor and at the same time for the entry of hot gas (Gc ).

With reference to Fig. 13, the connection portion (172) of the U-shaped tube (107) has a hole (174) in its lower part, which rests almost on the bottom of the separator (105). This hole (174) is used for the recovery of the oil inside the separator, which works due to the Venturi effect.

With the help of Figs. 14 and 15 describes a receiver â € “horizontal liquid separator for refrigeration cycle inversion units, according to the invention, indicated as a whole with the reference number (200).

The vertical receiver-separator (200) comprises an internal metal container (201) acting as a liquid receiver, arranged coaxially within an external metal container (205) acting as a gas separator.

The inner container (201) comprises a horizontal tubular body (210), with a side wall (211) welded by welding (S) on the left side.

A T-tube (208) is welded to the right side of the receiver (201). On the upper part of the T-tube (208) an upper wall (280) is welded, by means of welding (S).

The `` T '' tube (208) continues below with a section of vertical tube (281) under which a lower wall (282) is welded by welding (S). This particular realization allows that, when the almost empty receiver function is requested, the little refrigerant liquid contained on the bottom of the receiver `` T '' tube (208) does not undergo an excessive heat exchange with the hot gas in transit in the external container. (205), so that the liquid itself coming out of the receiver container (201) can correctly feed the lamination valve.

Optionally, two liquid level indicators (283, 284) can be fitted on the receiver `` T '' tube (208). The first indicator (283) is located higher to indicate a high level of coolant and the second indicator (284) is located lower to indicate a low level of liquid in the receiver. In this way, the user can check the refrigerant charge of the refrigeration circuit and the correct operation of the receiver according to the seasonal function.

On the lower part (281) of the receiver `` T '' tube there is a hole for the passage of a liquid outlet tube (202) (L), which protrudes radially from the lower part (281) of the â € œTâ €.

Instead, the liquid inlet (L) is made by means of an inlet pipe (203) which protrudes radially upwards, near the end of the receiver (201) opposite the â € œTâ € tube. . In this way the liquid (L) can cross the heat exchange surface. In this embodiment, unlike the vertical version, the two inlet (202) and outlet (203) pipes are distinct and not reversible from each other.

Outside the receiver (201) there is the external metal container (205) always suitable for operation under pressure, with the task of a gas separator, in the case in which the fresh gas from the compressor suction passes through it.

This separator (205) comprises a horizontal tubular body (250), of shorter length than that of the receiver, so as to leave a portion of the receiver uncovered on both sides.

The tubular body (250) of the separator has a larger external diameter than that of the receiver, so as to create a toroidal volume, between the two tubes, suitable for the operation of the gas separator.

Two circular side walls (251, 252) are fixed to the tubular body (250), by welding (S). Both side walls (251, 252) are centrally drilled to house the receiver tube (201), which is welded to the side walls (251, 252), by welding (S).

The separator (205) has in the lower part a collection tank (255) for oil and coolant liquid. Two holes (256, 257) are made in the collection tank (255). The first hole (256) has a horizontal axis to house a tube (206) for the hot gas (Gc) and fresh gas (Gf) inlet.

The second small hole (257) has a vertical axis and is placed in the center of the bottom of the tank. This hole (257) houses a flexible tube (209) which is used for the recovery of the oil inside the separator, operating by the Venturi effect. In fact, the flexible tube (209) is inserted inside a tube (207) for the fresh gas outlet (Gf).

This pipe (207) is inserted in a special hole with a vertical axis (257) on the top and central part of the tubular body (250) of the separator, so as to ensure that there is no return of refrigerant liquid at the compressor suction. The tube (207) also serves as a hot gas (Gc) inlet.

In the lower part of the separator (205) fixing supports (214) are welded to support the whole liquid separator receiver.

In both the vertical and horizontal versions, the portion of the receiver tube (101; 201) enclosed inside the external container (105; 205), with the function of gas separator, constitutes a sort of exchanger, allowing to vary slightly the temperature of the receiver itself, thanks to the transit of hot or fresh gas, depending on the operating mode. This small change in temperature allows the receiver to fill or empty. More precisely, with the transit in the external container (105; 205) of hot gas, the receiver (101; 201) is almost empty of refrigerant liquid. On the other hand, with the transit in the external container (105; 205) of fresh gas, i.e. when the receiver-separator (100; 200) is used as a gas separator, the receiver (101; 201) is almost full of coolant.

The operation of the separator receiver according to the invention is described below.

With reference to Figs. 16, 17 and 18 a generic receiver - separator (vertical or horizontal) according to the invention has been indicated with the reference number (15).

For now with reference to Fig. 16 (air / air unit) and Fig. 17 (air / water unit), the liquid separator receiver (15) must be almost empty of liquid during summer operation and almost full of liquid during winter operation.

Summer Operation:

the refrigerant gas compressed by the compressor (1) is directed by the four-way valve (2) in the external part of the receiver - liquid separator (15) and then exits the pipe that draws from the bottom always of the external part and goes to the heat exchanger side a lose (3) (which acts as a condenser) where it rejects heat, then heats. The condensed refrigerant liquid coming from the exchanger (3) through the check valve (4) is deposited in the internal part of the receiver - separator (15) (which acts as a receiver), then the liquid drawn from the bottom of the receiver expands in the thermostatically controlled lamination valve (6). The cold fluid exiting the lamination valve (6) goes to the user side exchanger (7) (which acts as an evaporator) where it subtracts heat and then cools; the gas then returns to the four-way valve (2) which directs it to the compressor (1).

Winter Operation:

the refrigerant gas compressed by the compressor (1) is directed by the four-way valve (2) to the user side exchanger (7) (which acts as a condenser) where it supplies heat and then heats. The refrigerant liquid condensed through the check valve (9) is deposited in the internal part of the receiver - liquid separator (15) (which acts as a receiver), then the liquid drawn from the bottom of the receiver expands in the lamination valve thermostatic control (10). The cold fluid exiting the lamination valve (10) goes to the disposable side exchanger (3) (which acts as an evaporator) where it subtracts heat and then cools. Then the refrigerant gas enters the external part of the receiver - liquid separator (15) (which acts as a gas separator) so that probable traces of liquid can be retained by it, thanks to the outlet obtained on the upper part of the separator. The gas then returns to the four-way valve (2) which directs it to the compressor (1).

With reference to Fig. 18, in the water / air units things are different in that the volumes of refrigerant contained inside the exchangers are reversed compared to the previous cases for which the receiver - liquid separator (15) must be almost full of liquid during summer operation and almost empty during winter.

Summer Operation:

the refrigerant gas compressed by the compressor (1) is directed by the four-way valve (2) to the heat exchanger on the disposable side (3) (which acts as a condenser) where it rejects the heat and then heats. The condensed refrigerant liquid coming out of the exchanger (3), through the check valve (4) is deposited in the internal part of the receiver - separator (15) (which acts as a receiver), then the liquid drawn from the bottom, expands in the thermostatic control lamination valve (6). The cold fluid coming out of the lamination valve goes to the user side exchanger (7) (which acts as an evaporator) where it subtracts heat and then cools. Then the refrigerant gas enters the external part of the receiver - liquid separator (15) (which acts as a gas separator), thanks to the outlet on the upper part, the gas then returns to the four-way valve (2) which directs towards the compressor (1).

Winter Operation:

the refrigerant gas compressed by the compressor (1) is directed by the four-way valve (2) to the external part of the receiver - liquid separator (15) and then comes out of the pipe which always draws from the bottom of the external part. The fluid then goes to the user side exchanger (7) (which acts as a condenser) where it supplies heat and then heats. The condensed refrigerant liquid coming from the exchanger (7) through the check valve (9) is deposited in the internal part of the receiver - liquid separator (15) (which acts as a receiver). Then the liquid drawn from the bottom, always from the inside, expands in the thermostatic control lamination valve (10). The cold fluid exiting the lamination valve goes to the heat exchanger on the disposable side (3) (which acts as an evaporator) where it subtracts heat and then cools. The gas then returns to the four-way valve (2) which directs it to the compressor (1).

Numerous variations and modifications of detail can be made to the present embodiments of the invention, within the reach of a person skilled in the art, however falling within the scope of the invention expressed by the appended claims.

Claims (11)

CLAIMS 1) Receiver unit - liquid separator for refrigeration cycle inversion unit for heat pump operation comprising: - a first container (101; 201) acting as a coolant liquid receiver; And - a second container (105; 205) acting as a gas separator from the refrigerant liquid; characterized by the fact that said first container (101; 201) is arranged coaxially within said second container (105; 205). 2) Receiver group - separator according to claim 1, characterized in that said first container (101, 201) is longer than said second container (105; 205) so that at least a lower portion (181; 281) of said first container (101; 201) is not covered by said second container, so that the liquid collected in said lower portion (181; 281) of the first container does not undergo a heat exchange with the second container (105; 205). 3) Receiver-separator unit according to claim 1 or 2, characterized in that said first container (101, 201) has a substantially cylindrical tubular shape and said second container (105; 205) has a substantially cylindrical toroidal shape. 4) Receiver - separator unit according to any one of the preceding claims, characterized in that said first container (101; 201) comprises a liquid outlet pipe (102; 201) and a liquid inlet pipe (103; 203) ( L) and said second container (105; 205) comprises a first pipe (106; 206) for cold gas inlet (Gf) and hot gas outlet (Gc) and a second pipe (107; 207) for hot gas inlet (Gc) and cold gas outlet (Gf). 5) Receiver - separator unit according to any one of the preceding claims, characterized in that it comprises two level indicators (140, 141; 283, 284) connected to said first container (101; 201) to detect a high liquid level and a low liquid level within said first container. 6) Receiver-separator unit according to any one of the preceding claims, characterized in that said first container (101) and second container (105) are arranged vertically. 7) Receiver - separator unit according to claim 6, characterized by the fact that said liquid outlet tube (102) has a first end that protrudes above from said first container and a second end that draws on the bottom of said first container and said liquid outlet pipe (103) has one end that protrudes from the top of said first container. 8) Receiver group - separator according to claim 6 or 7, characterized by the fact that said first pipe (106) for cold gas inlet (Gf) and hot gas outlet (Gc) has a first end that protrudes above from said second container and a second end that draws on the bottom of said second container and said second tube (107) for hot gas inlet (Gc) and cold gas outlet (Gf) has a substantially "U" shape and has a first end that protrudes above from said second container, a second end (173) which draws into the upper part of said second container and a hole (174) arranged on the lower part of said second tube, near the bottom of the second container. 9) Receiver - separator unit (200) according to any one of claims 1 to 5, characterized in that said first container (201) and second container (205) are arranged horizontally. 10) Receiver group - separator (200) according to claim 9, characterized by the fact that said tube (203) protrudes above from an end of said first container and a connected â € œTâ € duct (208) is provided at the other end of said container which provides a section of lower tube (281) from which said liquid outlet tube (202) emerges radially. 11) Receiver group - separator (200) according to claim 9, characterized by the fact that said second container (205) comprises a collection tank (255) which protrudes from below, in which said first tube (206) for inlet cold gas (Gf) and hot gas outlet (Gc) is connected to said collection tank (255) and said second pipe (207) for hot gas inlet (Gc) and cold gas outlet (Gf) protrudes radially towards the high from the upper central part of said second container, said collection tank (255) providing a hole (257) in its bottom wall connected to a small tube (209) that comes out of said second tube (207) for hot gas inlet (Gc ) and cold gas outlet (Gf).