KR20180135882A - A heat pump having refrigerant storage means - Google Patents

Abstract

A heat pump according to the present invention comprises at least one compressor; At least one condenser; At least one expansion valve; At least one evaporator; And at least one refrigerant storage means; Wherein the refrigerant storage means comprises at least one refrigerant storage space, the storage space having a high density and at least one discharge outlet, The low-density refrigerant outlet is divided, and the storage means includes means for transferring the refrigerant to the storage space, and the storage space is installed in parallel with the condenser and / or the evaporator.

Description

A heat pump having refrigerant storage means

The present invention relates to a heat pump. And more particularly, to a heat pump capable of individually controlling the inlet pressure and the outlet pressure of the compressor at the same time.

A heat pump is a device that transfers heat from a heat source to a destination called a "heater sink". A heat pump absorbs heat in a cold space and releases heat in a warm space. To do this, the heat pump uses a small amount of external energy to transfer energy from the heat source to the heat sink.

Air conditioners and refrigerators are typical examples of heat pumps. Also, a heat pump is an air conditioner (HVAC) for heating or cooling a certain space, a water purifier for providing cold / hot water, a dryer, a washing machine, and a vending machine.

Hereinafter, a heat pump operating in the cooling mode will be described with reference to Figs. 1 and 2. Fig.

In order to perform the refrigeration cycle, the refrigeration circuit is constituted by the compressor (C), the condenser (HXO), the expansion valve (EV) and the evaporator (HXI). The compressor (C) compresses the gas refrigerant. The condenser, which is a strong external heat exchanger (HXO), heat-exchanges the compressed gas refrigerant to produce liquid refrigerant. In an ideal condenser, only the phase transition occurs, so the temperature and pressure of the refrigerant do not change. The expansion valve (EV) expands the liquid refrigerant. The internal heat exchanger (HXI), which is the evaporator, exchanges the expanded liquid refrigerant to make gas refrigerant. The gas refrigerant that has passed through the evaporator enters the compressor (C) again and repeats the above cycle.

2 shows an example of a vehicle air-conditioner, which is designed with a condenser at 60 ° C and an evaporator at 0 ° C. Assuming that the outside air temperature is 30 ° C and the cooling setting temperature is 20 ° C, the 60 ° C gas refrigerant in the external heat exchanger (HXO), which is a condenser, releases heat to 30 ° C outdoors and becomes a liquid refrigerant at 60 ° C. In the internal heat exchanger (HXI), which is an evaporator, the 0 ° C liquid refrigerant becomes 0 ° C gas refrigerant (absorbs heat from room air above the set temperature). Since the ideal heat pump assumes no pressure changes in the condenser, the evaporator and the refrigerant piping, the inlet and outlet pressures of the compressor are representative of the evaporator and condenser temperatures for ease of understanding.

The problems of the prior art will be described below.

In the air conditioner, the amount of refrigerant passing through the evaporator per unit time (more widely circulating in the refrigeration circuit) is high, the compressor outlet pressure is high, and the condenser temperature (eg 60 ° C.) high. When the cooling load is large but the outside air temperature is low (eg, spring / autumn outside temperature 20 ° C, closed windows, restaurant kitchen, shopping mall ...). In this case, it is desirable to reduce the condenser temperature by lowering the compressor outlet pressure (eg, 40 ° C) to save energy.

In order to lower the compressor outlet pressure, if the operation of the compressor is reduced, the refrigerant circulation amount per unit time decreases, the cooling capability becomes lower, the compressor inlet pressure becomes higher, and the heat exchanging ability of the evaporator (HXI) decreases. Further, if the expansion valve is further opened to lower the compressor outlet pressure, there is a problem that the compressor inlet pressure is increased and the evaporator temperature is increased, thereby lowering the cooling capacity. In summary, conventionally, since the outlet pressure and the inlet pressure of the compressor C can not be individually adjusted at the same time, energy consumption is large.

In order to solve the above problem, the application number KR 10-2016-7026740 (US 2016/0370044 A1) and US 7,010,927 B2 propose an improvement, but the efficiency is low.

The present invention has been made in order to solve the problems of the prior art. More specifically, it is an object of the present invention to provide a heat pump capable of individually controlling the inlet pressure and the outlet pressure of the compressor at the same time.

To this end, the heat pump according to the present invention comprises at least one compressor; At least one condenser; At least one expansion valve; At least one evaporator; And at least one refrigerant storage means; Wherein the refrigerant storage means comprises at least one refrigerant storage space, the storage space having a high density and at least one discharge outlet, The low-density refrigerant outlet is divided, and the storage means includes means for transferring the refrigerant to the storage space, and the storage space is installed in parallel with the condenser and / or the evaporator.

At this time, the refrigerant storage space has a movable inner wall dividing one side and the other side; And the high-density refrigerant is stored in the one-side storage space. The means for transferring the refrigerant is preferably a reciprocating piston. The means for transferring the refrigerant is preferably a pump. The means for transferring the refrigerant is preferably a pressure of the gas refrigerant. Preferably, the refrigerant storage means includes at least one shut-off valve for shutting off the movement of the refrigerant.

A control method of a heat pump including a compressor, a condenser, an expansion valve, and an evaporator connected through a closed refrigerant line and connected to the refrigerant line to control a circulation amount of the refrigerant, ; Controlling the compressor inlet pressure by regulating the expansion valve and the compressor; And controlling the compressor outlet pressure by adjusting an amount of the refrigerant stored in the refrigerant storage means.

At this time, the refrigerant storage means has at least one refrigerant storage space, and the storage means includes means for transferring the refrigerant to the storage space, wherein the storage space is installed in parallel with the condenser and / or the evaporator; . The refrigerant storage space may include an inner wall dividing one side and the other side; And the high-density refrigerant is stored in the one-side storage space. Further, the means for transferring the refrigerant is a reciprocating piston; . The means for transferring the refrigerant may be a pump; . The means for conveying the refrigerant may be a pressure of the gas refrigerant; . Further, the refrigerant storage means may include at least one shut-off valve for shutting off the movement of the refrigerant; .

According to the heat pump of the present invention, there is an effect that a heat pump capable of individually controlling the inlet pressure and the outlet pressure of the compressor can be provided.

1 is an example of a conventional heat pump.
2 is an example of a ph diagram according to the prior art.
3 is an example of a heat pump according to the present invention.
4 is an example of a ph diagram according to the present invention.
5 is an example of another ph diagram according to the present invention.
6 to 10 are still other examples of the heat pump according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the same components are denoted by the same reference numerals as possible in the accompanying drawings. In addition, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms and should be construed in accordance with the technical concept of the present invention. Further, the detailed description of known configurations and functions that may be unnecessarily obscured by the gist of the present invention will be omitted.

For convenience of explanation, an ideal heat pump will be used unless otherwise specified. A key concept of the present invention is to provide refrigerant storage means in a heat pump and to adjust the amount of refrigerant circulating in the refrigerating circuit so that the inlet pressure and the outlet pressure of the compressor can be individually adjusted simultaneously.

<Key Concept Explanation>

Hereinafter, the core concept of the present invention will be described with reference to FIG.

3A and 3B, the heat pump 100 includes a compressor C1 for compressing a gaseous refrigerant; A condenser (HXO, external heat exchanger) that converts gas refrigerant of high temperature and high pressure into heat by exchanging heat; An expansion valve (EV) for expanding the refrigerant; An evaporator (HXI, internal heat exchanger) that converts the expanded refrigerant into heat by exchanging heat; And a refrigerant storage means (RS) for storing the refrigerant. In FIG. 3, the refrigerant storage means RS is arranged between the condenser (HXO) outlet and the expansion valve (EV) inlet.

3A and 3B, it is assumed that the compressor C1 compresses the same amount of refrigerant per unit time (in other words, the cooling load is the same) and assumes that the inlet pressure of the compressor C1 is fixed. The outlet pressure is determined by the amount of refrigerant stored in the refrigerant storage means (RS). More specifically, as shown in FIG. 3A, when a small amount of refrigerant is stored in the storage means RS, the outlet pressure of the compressor C1 is increased. When a large amount of refrigerant is stored as shown in FIG. 3B, Lt; / RTI &gt; To summarize the above description, the outlet pressure of the compressor (C1) can be controlled by the amount of refrigerant stored in the refrigerant storage means (RS).

Hereinafter, a method of adjusting the inlet pressure of the compressor C1 will be described.

The inlet pressure of the compressor (C1) is regulated by the operation of the expansion valve (EV) or the compressor (C1). More specifically, when the opening degree of the expansion valve EV is reduced, the amount of refrigerant passing through the expansion valve is reduced, so that the inlet pressure of the compressor C1 is lowered. Increasing the degree of opening also increases the inlet pressure of the compressor C1. When the amount of refrigerant compressed by the compressor C1 per unit time increases, the inlet pressure of the compressor C1 decreases. Conversely, when the amount of refrigerant compressed per unit time decreases, the inlet pressure of the compressor C1 increases.

As described above, in the heat pump 100, the refrigerant storage means (RS) is provided to individually control the compressor inlet pressure and the outlet pressure simultaneously.

Hereinafter, efficiency improvement according to the present invention will be described with reference to FIGS. 4 and 5. FIG.

First, the p-h diagram of FIG. 4 is an example of a vehicle air conditioner using R134a refrigerant. The refrigeration cycles (1) - (2) - (3) - (4) are ph diagrams according to the prior art, and the refrigeration cycles (1a) - (2) - (3) - (4a) It is leading.

When the opening degree of the expansion valve (EV) is increased in the conventional heat pump shown in Fig. 4, the compressor inlet pressure becomes high. More specifically, the refrigeration cycle (4) - (1) becomes the refrigeration cycle (4a) - (1a), and the evaporator temperature rises from 0 ° C to 10 ° C. This is the same as the conventional technique.

 In the prior art, if the opening degree of the expansion valve (EV) is increased, the refrigerant cycle (2) - (3) can not be maintained because the compressor outlet pressure is lowered. On the other hand, in the present invention, the amount of refrigerant stored in the refrigerant storage means (RS) can be reduced to increase the amount of refrigerant circulated in the refrigeration cycle. (Assuming that superheat and subcooling are properly maintained), the increased amount of refrigerant can increase the outlet pressure of compressor C1 and consequently maintain refrigeration cycles (2) - (3).

In summary, 1) the compressor (C1) compresses a predetermined amount of refrigerant per unit time, and the amount of refrigerant compression per unit time is determined by the size of the cooling load. 2) the expansion valve EV controls the inlet pressure of the compressor, and 3) the refrigerant storage means RS regulates the outlet pressure of the compressor C1.

Since the pressure and saturated vapor temperature are proportional, the outlet pressure of the compressor (C1) in the refrigerant p-h line represents the condenser temperature. (To be referred to as " representative " since the actual condenser is not a isothermal isothermal phase transition but a depressurization and depressurization phase), the compressor is preferably operated so that the condenser temperature is higher than the outside air temperature (e.g., 15 DEG C) C1), the energy consumption can be minimized.

The refrigeration cycle (1b) - (2b) - (3b) - (4b) according to the present invention in FIG. 5 sets the cooling set temperature to 25 ° C and the temperature difference suitable for heat exchange to 15 ° C when the outside air temperature is 35 ° C (For example, a condenser temperature = 50 DEG C and an evaporator temperature = 10 DEG C), and superheating degree and subcooling degree are appropriately controlled. More specifically, the refrigerant is R134a, and the superheat degree and the supercooling degree are respectively 5 占 폚. In the conventional refrigeration cycles (1) - (2) - (3) - (4), the performance coefficient is 2.25, and the refrigeration cycles 1b - 2b - 3b - Is 3.97. Therefore, according to FIG. 5 of the present invention, the coefficient of performance is improved by 76% (= 3.97 / 2.25 * 100) from the conventional one.

&Lt; Example 1 >

 In the heat pump according to the present invention, the compressor, the condenser, the expansion valve, and the evaporator are connected by a hermetically sealed refrigerant pipe to form a refrigeration circuit. Further, the refrigerant storage means is connected to the refrigerant pipe in parallel with the condenser. Then, the refrigerant storage means is adjusted to adjust the compressor outlet pressure.

Hereinafter, an embodiment (cooling mode) of the present invention will be described with reference to FIG.

Referring to FIG. 6, the heat pump 200 includes a compressor C1 for compressing gas refrigerant; A condenser (HXO, external heat exchanger) that converts the compressed gas refrigerant into heat by exchanging heat; An expansion valve (EV) for expanding the condensed liquid refrigerant; An evaporator (HXI, internal heat exchanger) that converts the expanded refrigerant into heat by exchanging heat; Is connected to a closed refrigerant pipe to constitute a refrigeration circuit. The refrigerant storage means RS1 is connected to the refrigerant pipe in parallel with the condenser HXO.

When the heat pump 200 is operated, high-pressure refrigerant is present in the refrigerant pipe from the outlet of the compressor C1 to the inlet of the expansion valve EV (hereinafter also referred to as a "high-pressure line"), (Hereinafter also referred to as " low-pressure line ") exists in the refrigerant pipe to the inlet of the compressor C1.

Here, the refrigerant storage means RS1 includes: a cylinder having an internal space for storing refrigerant; An inner wall dividing one side (Ra) and the other side (Rb) of the inner space; And a piston (PR1) reciprocating the inner wall in the inner space. The storage space Ra is connected to the outlet of the condenser HXO to store a refrigerant in a liquid state (high density), and the storage space Rb is connected to an inlet of the condenser HXO, ) Refrigerant is stored. Then, when the piston PR1 moves, the inner wall connected to the piston PR1 moves so that the storage space at one side increases and the storage space at the other side decreases.

In the ideal heat pump condenser, the pressure inside the refrigerant storage space (Ra) and the storage space (Rb) are the same because the isothermal isothermal phase transformation occurs. The same refrigerant is stored in the two storage spaces, but the amount of refrigerant stored in the refrigerant storage means RS1 is changed when the piston PR1 is moved because one refrigerant is a liquid refrigerant having a high density and the other is a low density gas refrigerant. At this time, assuming that the amount of refrigerant compression per unit time of the compressor (C1) and the temperature of the evaporator (HXI) do not change, the amount of refrigerant present in the " low pressure line " If the amount of refrigerant stored in the refrigerant storage means RS1 is adjusted, the outlet pressure of the compressor C1 is adjusted if the supercooling degree is properly maintained in the condenser HXO.

In this embodiment, the refrigerant storage means RS1 is connected to the inlet and the outlet of the condenser HXO to store the liquid refrigerant in one of the storage spaces Ra and the gas refrigerant in the other storage space Rb. Meanwhile, the refrigerant storage means RS1 of the present invention may be installed inside the condenser HXO. More specifically, gas refrigerant having relatively higher humidity than that of the other storage space (Rb) is stored in one storage space (Ra).

The advantage of this embodiment is that since the pressures of the two refrigerant storage spaces Ra and Rb are the same, the refrigerant storage amount can be changed by moving the piston PR1 with very little energy. Further, all of the liquid refrigerant stored in the refrigerant storage means RS1 is discharged through the expansion valve EV and used for cooling so that energy efficiency is high.

In Fig. 6, the refrigerant storage means (RS1) is arranged in the " high pressure line ". Even if the refrigerant storage means according to the present invention is arranged in the "low pressure line" after the expansion valve (that is, the refrigerant storage means is connected in parallel with the evaporator), the outlet pressure and inlet pressure of the compressor pursued by the present invention It is natural to be able to control.

7, the heat pump 300 transfers refrigerant to the refrigerant transfer pump P1 to adjust the refrigerant storage amount. Here, the refrigerant storage means RS3 is connected in parallel with the condenser HXO. More specifically, the refrigerant storage space of the refrigerant storage means RS3 includes a movable inner wall divided into one side and the other side, one side being a high-density refrigerant storage space (Ra), the other side being a low-density refrigerant storage space (Rb) to be. The refrigerant storage means RS3 includes a refrigerant transfer pump P1 and a four-way valve V4p which is a refrigerant passage changing means.

The outlet of the refrigerant transfer pump P1 is connected to the liquid refrigerant storage space Ra and the inlet of the refrigerant transfer pump P1 is connected to the outlet of the condenser HXO, When the refrigerant transfer pump P 1 transfers the refrigerant, the refrigerant storage amount in the liquid refrigerant storage space Ra is increased, and the outlet pressure of the compressor C 1 is lowered.

 On the other hand, in FIG. 7, the four sides V4p rotate 90 degrees and the outlet of the refrigerant transfer pump P1 is connected to the outlet of the condenser HXO, (Ra), and when the refrigerant transfer pump (P1) transfers the refrigerant, the refrigerant storage amount in the liquid refrigerant storage space (Ra) decreases and the outlet pressure of the compressor (C1) increases.

On the other hand, it is a matter of course that the function of the movable inner wall of the refrigerant storage means RS3 can be realized by a diaphragm (see US 2016/0370044 A1).

&Lt; Example 2 >

Hereinafter, an embodiment (cooling mode) of the present invention will be described with reference to FIG. FIG. 8 is a modification of the refrigerant storage means of FIG. 7 and is characterized by having a single refrigerant storage space.

First, the structure of the heat pump 400 includes a compressor (C1) for compressing gas refrigerant; A condenser (HXO, external heat exchanger) that converts the compressed gas refrigerant into heat by exchanging heat; An expansion valve (EV) for expanding the condensed liquid refrigerant; An evaporator (HXI, internal heat exchanger) that converts the expanded refrigerant into heat by exchanging heat; Is connected to a closed refrigerant pipe to constitute a refrigeration circuit.

The refrigerant storage means RS4 is connected to the refrigerant pipe in parallel with the condenser HXO. More specifically, the refrigerant storage means RS4 includes one storage space Rc for storing the refrigerant, a refrigerant transfer pump P2 for introducing or discharging the liquid refrigerant into the refrigerant storage space Rc, And a liquid refrigerant shutoff valve (V1) and a gas refrigerant shutoff valve (V2) for blocking inflow and outflow of the refrigerant into the storage space (Rc).

When the heat pump 400 is operated, high-pressure refrigerant exists in the refrigerant pipe from the outlet of the compressor C1 to the inlet of the expansion valve EV (hereinafter also referred to as a "high-pressure line"), (Hereinafter also referred to as " low-pressure line ") exists in the refrigerant pipe to the inlet of the compressor C1.

One side entrance of the refrigerant storage space Rc is connected to the inlet of the condenser HXO so as to allow the gas refrigerant to flow in and out (hereinafter, also referred to as a "low-density refrigerant inlet"), (Hereinafter also referred to as a " high-density refrigerant outlet port "), and the refrigerant transfer pump P2 and the liquid refrigerant shutoff valve V1 are connected to the outlet of the condenser HXO, Quot; doorway " The gas refrigerant shutoff valve V2 is installed between the inlet of the condenser HXO and the " low-density refrigerant inlet ". [In this specification, the gas refrigerant shutoff valve (V2) is always fully open, unless otherwise specified. ]

Here, it is preferable that the refrigerant transfer pump P2 is a pump capable of forward / reverse rotation and a direction in which the refrigerant transfer direction is determined by the rotation direction. When the liquid refrigerant shutoff valve V1 is completely opened, it is preferable that a predetermined minimum amount of liquid refrigerant is stored in the refrigerant storage means RS4 so that the liquid refrigerant always exists in the refrigerant transfer pump P2 . This is because the pressure of the gas entering the " low-density refrigerant inlet " at the outlet of the compressor C1 and the pressure of the liquid entering the " high-density refrigerant inlet " at the outlet of the condenser (HXO) ).

More specifically, when the vertical position of the refrigerant storage space Rc is further lowered in FIG. 8, more liquid refrigerant will be stored in the refrigerant storage space Rc. Conversely, if the vertical position of the refrigerant storage space Rc is further increased, the liquid refrigerant will be stored in the refrigerant storage space Rc less.

A pressure drop (hereinafter referred to as " piping resistance ") occurs when the refrigerant passes through the piping. The piping resistance of the gas refrigerant piping phgas and the piping resistance of the condenser HXO and the liquid refrigerant piping phliq are appropriately adjusted so that when the liquid refrigerant shutoff valve V1 is completely opened, A predetermined amount of liquid refrigerant is stored, and a liquid refrigerant is present in the refrigerant transfer pump P2.

When the refrigerant transfer pump P2 operates to introduce the refrigerant into the refrigerant storage space Rc, the stored amount of the liquid refrigerant in the refrigerant storage space Rc increases. Conversely, when the refrigerant transfer pump P2 operates to discharge the refrigerant in the refrigerant storage space Rc, the stored amount of the liquid refrigerant in the refrigerant storage space Rc decreases. At this time, assuming that the amount of refrigerant compression per unit time of the compressor (C1), the temperature of the evaporator (HXI), and the degree of superheat do not change, the amount of refrigerant present in the "low pressure line" remains unchanged. If the amount of refrigerant stored in the refrigerant storage means RS4 is adjusted, the outlet pressure of the compressor C1 is adjusted if the subcooling degree of the condenser HXO is appropriately maintained.

When it is necessary to store the same amount of refrigerant for a long time in the refrigerant storage means RS4, the liquid refrigerant shutoff valve liquid V1 and the gas refrigerant shutoff valve V2 are completely closed and the operation of the refrigerant transfer pump P2 is stopped .

When the heat pump 400 finishes operation, the refrigerant flows into a fine gap in the compressor C1, so that the pressures of the "high pressure line" and the "low pressure line" become equal. This is just tossing the work of the compressor (C1). When the shutoff valve V1 (V2) is fully locked before the compressor (C1) is stopped, the energy of the refrigerant stored in the refrigerant storage means (RS4) can be used immediately after the heat pump (400) to be.

The operation of the refrigerant transfer pump P2 is determined by the requirements of a specific situation. In this specification, the operation of the feed pump P2 is adjusted according to a request to set the temperature difference between the outside air temperature and the condenser at an appropriate level. It is natural that the feed pump P2 can be finely adjusted for the purpose of controlling the supercooling degree.

 On the other hand, it is a matter of course that the " piping resistance " of the gas refrigerant piping (phgas) can be adjusted by opening the gas refrigerant shutoff valve V2. Although the refrigerant storage means RS4 is connected in parallel with the condenser HXO in this embodiment, it is natural that the refrigerant storage means RS4 is connected in parallel with the evaporator HXI.

Hereinafter, another preferable operation method of the heat pump 400 will be described.

First, when the shutoff valve V1 (V2) of the heat pump 400 is completely opened and the transfer pump P2 is stopped, the liquid refrigerant in the refrigerant storage space Rc is supplied to the gas refrigerant piping (phgas) Install the refrigerant piping (phliq) (by calculating the piping resistance value). (Hereinafter referred to as " stored refrigerant amount increase condition "),

When the compressor C1 of the heat pump 400 starts to operate, the shutoff valve V1 (V2) is opened and the transfer pump P2 is operated in the direction in which the liquid refrigerant in the refrigerant storage space Rc is reduced , &Quot; condition for reducing the amount of stored refrigerant "). Then, after a predetermined time (when the liquid refrigerant in the refrigerant storage space Rc becomes the predetermined minimum amount or less), the liquid refrigerant shutoff valve V1 is closed and the transfer pump P2 is stopped. Then, the circulating refrigerant amount of the refrigerating circuit of the heat pump 400 and the outlet pressure of the compressor (C1) are maximized.

If the outlet pressure of the compressor (C1) of the heat pump (400) is to be lowered, the shutoff valve (V1) (V2) and the shutoff valve Operate the feed pump (P2).

The heat pump 500 shown in Fig. 9 changes the position of the refrigerant transfer pump in the heat pump 400 shown in Fig. 8 and removes the shutoff valve V2. More specifically, in the heat pump 500, the refrigerant transfer pump P3 is disposed between the condenser HXO and the expansion valve EV. One side entrance of the refrigerant storage space Rd is connected to the inlet of the condenser HXO so that the gas refrigerant enters and exits (hereinafter, also referred to as a "low-density refrigerant inlet") and the other side of the refrigerant storage space Rd is connected (Hereinafter also referred to as a " high-density refrigerant inlet "), and the liquid refrigerant shutoff valve V1 is installed between the outlet of the refrigerant transfer pump P3 and the " high- do.

The piping resistance of the gas refrigerant piping (phgas) in the heat pump 500 is preferably smaller than the piping resistance of the condenser HXO and the liquid refrigerant piping (phliq). It is preferable that the size of the impeller of the refrigerant transfer pump P3 is smaller than the inside diameter of the refrigerant pipe so that the refrigerant can flow through the refrigerant transfer pump P3 even when the refrigerant transfer pump P3 does not operate. The refrigerant transfer pump P3 is preferably a pump for transferring the refrigerant in one direction.

Hereinafter, a preferred method of operating the heat pump 500 will be described.

It is preferable that the refrigerant transfer pump P3 is in the stopped state and the shutoff valve V1 is in the fully opened state (hereinafter referred to as " stored refrigerant amount reducing condition ") when the compressor C1 of the heat pump 500 starts to operate Do. Then, since the piping resistance at the "low-density refrigerant inlet" side of the refrigerant storage means is lower than the piping resistance at the "high-density refrigerant inlet", the gaseous refrigerant in the refrigerant storage space Rd increases and the refrigerant in the liquid state decreases . After a predetermined time, the shutoff valve V1 is completely closed. At this time, it is preferable that only the gas refrigerant is present in the refrigerant storage space Rd. (Refrigerant storage means initialization completion)

When it is necessary to lower the outlet pressure of the compressor C1 and the representative temperature of the condenser in the state in which the heat pump 500 is operated, the refrigerant transfer pump P3 is operated and the shutoff valve V1 is opened Quot; stored refrigerant amount increase condition "). Then, the liquid refrigerant is introduced into the refrigerant storage space Rd by the refrigerant transfer pump P3, and the refrigerant in the liquid state increases in the refrigerant storage space Rd, and the refrigerant in the gaseous state decreases.

When it is not necessary to adjust the amount of refrigerant stored in the refrigerant storage space Rd of the heat pump 500, the shutoff valve V1 is completely closed and the refrigerant transfer pump P3 is stopped (hereinafter referred to as " ).

&Lt; Example 3 >

Hereinafter, an embodiment (cooling mode) of the present invention will be described with reference to FIG. Fig. 10 is a modification of the refrigerant storage means RS3 of Fig. 7, and is characterized in that the refrigerant storage amount is controlled to be the pressure of the gas refrigerant.

 First, referring to the structure of the heat pump 600, a compressor C1 compresses gas refrigerant; A condenser (HXO, external heat exchanger) that converts the compressed gas refrigerant into heat by exchanging heat; An expansion valve (EV) for expanding the condensed liquid refrigerant; An evaporator (HXI, internal heat exchanger) that converts the expanded refrigerant into heat by exchanging heat; Is connected to a closed refrigerant pipe to constitute a refrigeration circuit.

The refrigerant storage space of the refrigerant storage means RS6 includes a movable inner wall divided into one side and the other side, one side being a high-density refrigerant storage space (Ra) and the other side being a low-density refrigerant storage space (Rb). And a reducing valve V3 and an increasing valve V4 for adjusting the liquid refrigerant storage amount. The liquid refrigerant storage space Ra and the gas refrigerant storage space Rb are connected in parallel with the condenser HXO. The high-density refrigerant storage space Ra is connected to the outlet of the condenser (HXO) to allow liquid refrigerant to flow in or out. The low-density refrigerant storage space Rb is connected to the inlet of the condenser HXO through the reducing valve V3 to introduce the gaseous refrigerant and the gaseous refrigerant flows out through the increase valve V4 to the inlet of the compressor C1. The refrigerant storage means RS6 described above is connected in parallel to the condenser HXO (if narrowly construed on the basis of the refrigerant storage space Ra (Rb) which is a core component).

When the heat pump 600 is operated, high-pressure refrigerant exists in the refrigerant pipe from the outlet of the compressor C1 to the inlet of the expansion valve EV (hereinafter also referred to as a "high-pressure line"), (Hereinafter also referred to as " low-pressure line ") exists in the refrigerant pipe to the inlet of the compressor C1.

First, a method of increasing the amount of refrigerant stored in the refrigerant storage means (RS6) will be described. When the refrigerant reducing valve V3 is closed and the refrigerant increasing valve V4 is opened, the gas refrigerant storage space Rb is connected to the "low pressure line", and the pressure inside the storage space Rb is lowered. As a result, the volume of the gas refrigerant storage space (Rb) is reduced and the volume of the liquid refrigerant storage space (Ra) is increased to increase the amount of refrigerant stored in the refrigerant storage means (RS6).

 A method of reducing the amount of refrigerant stored in the refrigerant storage means RS6 will be described. When the refrigerant reducing valve V3 is opened and the refrigerant increasing valve V4 is closed, the gas refrigerant storage space Rb is connected to the "high pressure line", the high-pressure gas refrigerant flows into the storage space Rb, As a result, the volume of the gas refrigerant storage space Rb increases and the volume of the liquid refrigerant storage space Ra decreases, thereby reducing the amount of refrigerant stored in the refrigerant storage means RS6. [Condition: Piping resistance from the outlet of the compressor (C1) to the gas refrigerant storage space (Rb) <Piping resistance from the outlet of the compressor (C1) to the liquid refrigerant storage space (Ra)

<Example 4>

The present embodiment is one embodiment for explaining the (cooling mode) heat pump driving method.

This will be described below with reference to FIG. Since the structure of the heat pump 200 has been described in detail in the first embodiment, it will be omitted.

The control method for the heat pump 200 includes the steps of setting the condenser target temperature, setting the evaporator target temperature, controlling the compressor inlet pressure by regulating the expansion valve and the compressor, and storing the refrigerant in the refrigerant storage means And controlling the compressor outlet pressure by adjusting the amount of refrigerant to be supplied to the compressor. Here, the step of controlling the evaporator superheating degree and / or the step of controlling the condenser supercooling may be further included.

Hereinafter, a heat pump control method according to the present invention will be described as an example

1) It is desirable to obtain the evaporator target temperature by formula (1) or formula (2).

     Evaporator target temperature = Emission temperature - Td - - - (Equation 1)

     Evaporator target temperature = cooling set temperature - Td - - - (Equation 2)

Here, Td is a predetermined value (e.g., 15.0) greater than zero. The inside temperature is the current temperature of the space to be cooled. Td can be increased if the cooling load (in other words, the circulating refrigerant amount per unit time) is large, and decreases if it is small.

The compressor inlet pressure target value is found in the refrigerant pressure-temperature chart using the evaporator target temperature. It is preferable that the current cooling load magnitude is obtained by using the temperature difference (= the inside temperature - the target temperature of the evaporator) and the size of the cooling space.

2) The inlet pressure of the compressor (C1) is controlled by adjusting the expansion valve (EV) and the compressor (C1).

(Assumption 1) The evaporator (HXI) target temperature is 16 ° C, (assumption 2) superheat is very well controlled, and (assumption 3) the refrigerant particles (Ie, the ideal inlet pressure of the compressor (C1)) is 4 (4), the pressure in the evaporator (HXI) (Assumption 4) Assume that the temperature corresponding to 4 atmospheric pressure in the refrigerant pressure-temperature chart used is 16 ° C.

Here, there are many driving conditions of the expansion valve (EV) and the compressor (C1) for setting the inlet pressure of the compressor (C1) to 4 atm. The amount of refrigerant flowing into the evaporator HXI (via the expansion valve EV) and the amount of refrigerant flowing out of the evaporator HXI (via the compressor C1) are calculated in the state where 400 refrigerant particles exist in the present evaporator HXI If the amount of refrigerant is equalized, the pressure inside the evaporator (HXI) is always 4 atm. And the evaporator (HXI) temperature is always 16 ℃.

Therefore, according to (Assumption 1) to (Assume 4), 400 refrigerant particles exist in the evaporator HXI, while when the cooling load is large, the amount of refrigerant passing through the evaporator per unit time is increased, It is preferable to drive the heat pump by a method of reducing the amount of refrigerant passing through the evaporator per hour. This is particularly preferable when the cooling air volume of the heat pump is in the automatic adjustment mode.

Unlike an electric car, an engine car is usually driven by a car engine. Since the engine rotation speed (RPM) changes from time to time during vehicle operation, the compression speed of the compressor also changes from time to time. According to the present invention, it is preferable that the amount of refrigerant passing through the compressor per unit time is constant. Therefore, it is preferable that the amount of the compressed refrigerant once decreases when the engine rotation speed becomes higher and the amount of compressed refrigerant once increases when the engine rotation speed becomes lower.

3) The degree of superheat is particularly preferably obtained by the formula (3).

Overheat = actual temperature - theoretical temperature - - - (Equation 3)

Here, the measured temperature is the refrigerant temperature measured at the outlet of the evaporator (HXI). The theoretical temperature is obtained from the refrigerant pressure-temperature chart used. At this time, the pressure obtained from the measured temperature measurement site is used.

3-1) When the cooling air flow rate is in the automatic adjustment mode: The amount of refrigerant passing through the evaporator (HXI) per unit time is determined by the cooling load [Step 2]. The superheat degree is determined by the speed of the evaporator fan (FNI) .

More specifically, a high degree of superheat reduces the heat supplied to the evaporator (HXI) from the inside air (eg, by lowering the evaporator fan (FXI) rate) to reduce the superheat. If the superheat is low, increase the heat supplied to the evaporator (HXI) from the vent (eg by increasing the evaporator fan (FXI) speed). In actual implementation of the method, the superheat degree and the target difference are small, and due to the limitation of each accessory, the opening of the expansion valve (EV) and / or the compressor (C1) is controlled more finely than the evaporator fan The degree of superheat is preferably controlled by an expansion valve or / and a compressor. At this time, the inlet pressure of the compressor (C1) will be approximately equal to the target pressure.

3-2) When the cooling air flow rate is in the manual adjustment mode: The air flow rate, ie the evaporator fan (FXI) speed, is already set manually. Therefore, it is preferable to control the degree of superheat by the amount of circulating refrigerant per unit time.

More specifically, if the amount of refrigerant passing through the evaporator (HXI) per unit time is lower than a proper level, the amount of cool air is reduced and the degree of superheat increases. If the amount of coolant is higher than a proper level, superheat is reduced. Therefore, it is preferable to control the degree of superheat by controlling the amount of refrigerant passing through the evaporator (HXI) per unit time.

Here, the amount of refrigerant passing through the evaporator HXI per unit time is preferably controlled by the expansion valve EV and the compressor C1. At this time, it is natural that the temperature of the evaporator (HXI) and the inlet pressure of the compressor (C1) are determined by the number of refrigerant particles present in the evaporator (HXI). It is a matter of course that the superheat degree is controlled without changing the inlet pressure of the compressor C1.

(If the air volume is in the manual adjustment mode, but a little air volume variation is allowed.) In realizing this method, the superheat degree and the target difference are small, and due to the limitation of each accessory, the evaporator fan (FXI) If it is possible to control the degree of superheat more finely or easily than the degree of opening of the expansion valve (EV) or the compressor (C1), the superheat degree is preferably controlled by the evaporator fan (FXI). At this time, the inlet pressure of the compressor (C1) will be approximately equal to the target pressure.

4) The outlet pressure of the compressor (C1) (condenser target temperature) is controlled by the refrigerant storage means.

It is preferable that the condenser target temperature is obtained by (formula 4) or (formula 5).

  Condenser target temperature = ambient temperature + Td - - - (Equation 4)

  Condenser target temperature = ambient temperature + Td - Cs   - - - (Equation 5)

Here, Td is a predetermined value (e.g., 15.0) greater than zero. Td can be increased if the cooling load (in other words, the circulating refrigerant amount per unit time) is large, and decreases if it is small. And Cs is a variable considering the increase in the amount of heat exchanged due to an increase in the amount of air passing through the condenser as the vehicle speed increases.

4-1) For stationary heat pump installed in a building: The condenser target temperature is preferably determined by formula (4).

The heat quantity to be dissipated in the condenser (HXO) can be obtained by using the amount of circulating refrigerant per unit time and the outlet pressure of the compressor (C1) (in other words, the heat energy to phase-shift gas into liquid in the refrigerant pressure-temperature chart used) . It is a matter of course that the air volume of the condenser fan (FNO) can be obtained from the calculated amount of heat radiation. At this time, the subcooling degree is preferably achieved by finely adjusting the air volume of the condenser fan (FNO).

4-2) For a mobile heat pump installed in a vehicle: The target temperature of the condenser is preferably obtained by the formula (5). At this time, it is preferable that the variable Cs varying according to the vehicle speed is large when the vehicle speed is high and small when the vehicle speed is low.

5) The subcooling degree is preferably determined by the following equation (6).

Subcooling = measured temperature - theoretical temperature - - - (Equation 6)

Here, the actual temperature is the refrigerant temperature measured at the outlet of the condenser (HXO). The theoretical temperature is obtained from the refrigerant pressure-temperature chart used. At this time, the pressure obtained from the measured temperature measurement site is used.

In order to increase the heat pump performance coefficient, the subcooling degree is preferably controlled to an appropriate value. The supercooling degree may fluctuate due to the external humidity, the wind speed of the natural wind, and the like. Therefore, the supercooling degree is preferably achieved by adjusting the air flow rate of the condenser fan (FNO). If the speed of the condenser fan FNO is near the limit value, it is of course possible to adjust the subcooling degree to the outlet pressure of the compressor C1. For example, if the air volume of the condenser fan (FNO) is maximum and the subcooling is low, the outlet pressure is slightly higher. When the air volume of the condenser fan (FNO) is minimum and the supercooling degree is high, the outlet pressure is further lowered.

The heat pump control method described in this embodiment is a procedure including a plurality of cases. Therefore, in actual heat pump implementation, several steps can be selected selectively. Since the control procedure described above is not a fixed order, it may be arranged in a different order. It goes without saying that the heat pump control method described in the present embodiment is also applicable to conventional application numbers KR 10-2016-7026740 (US 2016/0370044 A1) and US 7,010,927 B2.

One embodiment of the heat pump driving method of the present invention has been described in detail above.

The function of the inner wall movable in the refrigerant storage means (RS1) (RS3) (RS6) of the present invention can be realized by a diaphragm. More specifically, as described in US2016 / 0370044 A1, the amount of refrigerant stored in the refrigerant storage means RS1 (RS3) (RS6) can be adjusted by displacement and / or deformation of the diaphragm. Therefore, the movable inner wall in the present invention should be interpreted as including a rigid inner wall, displacement and / or a deformed inner wall.

In the present invention, the case of operating the heat pump in the cooling mode has been described in detail, but it is natural that the concept of the present invention can be applied in the heating mode. That is, the compressor inlet pressure and the outlet pressure are individually adjusted so that the temperature of the condenser and the vaporizer, which are heat exchangers, is lower than the temperature of the air used for heat exchange ("liquid" in the case of a water tank, "medium" It is possible to set it as high or low as the value Thus, an energy-saving heat pump is provided, since heat exchange can be performed with an optimum temperature difference with the heat exchange medium.

Although the embodiments of the present invention have been described with respect to one compressor, an outdoor heat exchanger, an indoor heat exchanger, an expansion valve, and a refrigerant storage unit, it is obvious to those skilled in the art that the present invention can also be implemented in a heat pump using a plurality of components .

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. Therefore, the embodiments of the present invention disclosed in the present specification and drawings are merely illustrative of the technical contents of the present invention and are intended to illustrate specific examples of the present invention in order to facilitate understanding of the present invention, and are not intended to limit the scope of the present invention.

According to the heat pump of the present invention, when the cooling load is large but the outside air temperature is low (for example, spring / autumn (outdoor temperature 20 ° C), a restaurant kitchen using lots of fire, Energy can be saved by lowering the compressor outlet pressure to enable optimal heat exchange. Therefore, the possibility of industrial use is very high.

Particularly, in automobiles, even when the outside air temperature of the vehicle is low, there are many cases where the cooling load is high due to the greenhouse effect (for example, when the vehicle window is closed and moved). Since the heat pump for an energy saving vehicle is provided with the present invention, the possibility of industrial use is very high.

Claims (13)

In the heat pump,
At least one compressor; At least one condenser; At least one expansion valve; At least one evaporator; And at least one refrigerant storage means; / RTI &gt;
The refrigerant circuit (compressor, condenser, expansion valve, evaporator) is connected by a closed refrigerant pipe,
The refrigerant storage means has at least one refrigerant storage space,
The storage space is divided into high-density and low-density refrigerant outlets,
The storage means comprising means for transferring the refrigerant to the storage space,
Wherein the storage space is provided in parallel with the condenser and / or the evaporator. The method according to claim 1,
The refrigerant storage space includes a movable inner wall dividing one side and the other side; Wherein the one side storage space stores higher-density refrigerant than the other side. 3. The method of claim 2,
Wherein the means for transferring the refrigerant is a piston that reciprocates. The method according to claim 1,
The means for transferring the refrigerant is a pump. The method according to claim 1,
Wherein the means for transferring the refrigerant is a pressure of the gas refrigerant. The method according to claim 1,
Wherein the refrigerant storage means includes at least one shut-off valve for shutting off the movement of the refrigerant. A method of controlling a heat pump including a compressor, a condenser, an expansion valve, and an evaporator connected through a closed refrigerant line and connected to the refrigerant line to control a circulation amount of the refrigerant,
Setting the condenser target temperature;
Controlling the compressor inlet pressure by regulating the expansion valve and the compressor; And
And controlling the compressor outlet pressure by adjusting the amount of refrigerant stored in the refrigerant storage means. 8. The method of claim 7,
The refrigerant storage means has at least one refrigerant storage space,
The storage means comprising means for transferring the refrigerant to the storage space,
Wherein the storage space is provided in parallel with the condenser and / or the evaporator. 9. The method of claim 8,
The refrigerant storage space includes an inner wall dividing one side and the other side; Further comprising:
Wherein one side storage space stores higher-density refrigerant than the other side; Wherein the heat pump control method comprises : 9. The method of claim 8,
Wherein the means for transferring the refrigerant is a reciprocating piston; Wherein the heat pump control method comprises : 9. The method of claim 8,
The means for transferring the refrigerant is a pump; Wherein the heat pump control method comprises : 9. The method of claim 8,
The means for conveying the refrigerant is a pressure of the gas refrigerant; Wherein the heat pump control method comprises : 9. The method of claim 8,
The refrigerant storage means including at least one shut-off valve for blocking the movement of the refrigerant; Wherein the heat pump control method comprises :

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