JP3334507B2 - Refrigeration system device and control method for refrigeration system device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention controls an opening area of each adjusting means provided between a condenser and an evaporator and disposed before and after a receiver tank for storing a refrigerant to optimize a refrigeration cycle. The present invention relates to a refrigeration system device to be maintained.

[0002]

2. Description of the Related Art FIG.
In the figure, reference numeral 3 denotes a compressor, 4 denotes an outdoor heat exchanger, 5 denotes a four-way valve,
6a, 6b, 6c indoor heat exchangers, 11a, 11b, 11
c is a receiver tank, an electric expansion valve, 12 is a receiver tank, 13 is a main electric expansion valve, and 14 is a suction pipe.

Next, the operation will be described. For example, during heating, the refrigerant compressed by the compressor 3 is supplied to each indoor heat exchanger 6.
After passing through a to c, the throttles are throttled by the respective electric expansion valves 11 a to 11 c, passed through the receiver tank 12, sent to the outdoor heat exchanger 4 via the main electric expansion valve 13, and then sucked into the compressor 3. . At this time, by adjusting the opening area of the main electric expansion valve 13 based on the superheat degree of the refrigerant temperature on the outlet side of the outdoor heat exchanger 4, the superheat degree of the suction refrigerant superheat of the compressor while accumulating the surplus refrigerant in the receiver tank 12 And the temperature of the refrigerant discharged from the compressor. Further, before and after the receiver tank 12, the main electric expansion valve 13 and the electric expansion valves 11a, 11b, 11c are arranged.
The same control can be performed even during cooling due to the presence of both.

[0004]

Since the conventional refrigeration system apparatus is constructed as described above, it is necessary to determine whether the temperature of the receiver tank is higher or lower based on the degree of superheating of the refrigerant gas suction temperature of the compressor or the refrigerant discharge temperature of the compressor. Since the opening areas of the expansion valves (adjustment means for adjusting the pressure or the flow rate) are controlled respectively, there is a problem that the operation is performed in a refrigeration cycle having poor operation efficiency. In particular, when the number of operating indoor units during the cooling / heating operation in the multi-room refrigeration cycle changes, the expansion valves (adjustment means) in front and behind the receiver tank affect each other's operation, and hunting occurs. As a result, there has been a problem that the refrigeration cycle of the system is not easily stabilized or it takes a long time to stabilize.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an economical and highly reliable refrigeration system apparatus that maintains a stable operation state in a refrigeration cycle state with always high operation efficiency. The purpose is to gain.

Further, even when the operating state of the refrigeration system device changes (for example, when the number of operating indoor units in a multi-room refrigeration system device changes), hunting of the refrigeration cycle (refrigerant flow rate and pressure in the cycle). To prevent large fluctuations in a short period of time), reach a refrigeration cycle with high operating efficiency in a short time, greatly improve the annual average operating efficiency, and maintain economical and stable operation The purpose is to obtain a reliable refrigeration system device.

[0007]

A refrigeration system according to the present invention comprises a compressor, a condenser, a high-pressure-side expansion device, a receiver tank, a low-pressure-side expansion device, and an evaporator which are sequentially connected by piping. A refrigerating device, supercooling detecting means for detecting a subcooling characteristic value corresponding to a degree of subcooling of a refrigerant at a condenser outlet of the refrigerating device, and detecting a superheat characteristic value corresponding to a degree of superheating of a refrigerant sucked into the compressor. Overheating detection means, and the high-pressure side and low-pressure side expansion device so that each detection result of the supercooling detection means and the overheating detection means is close to a target value based on the current opening area of the high-pressure side and low-pressure side expansion device. Control means for correcting the opening area.

[0008] A refrigeration system in which a compressor, a condenser, a high-pressure-side expansion device, a receiver tank, a low-pressure-side expansion device, and an evaporator are sequentially connected by piping, and supercooling of refrigerant at the condenser outlet of the refrigeration system. Supercooling detecting means for detecting a supercooling characteristic value corresponding to the temperature, superheat detecting means for detecting a superheat characteristic value corresponding to the degree of superheating of the suction refrigerant of the compressor, and the supercooling detecting means and the superheat detecting means. Calculating means for calculating each deviation value between each detection result and a target supercooling characteristic value and a target superheating characteristic value corresponding to the operation state of the refrigeration apparatus; and the high-pressure side and the low-pressure side based on the calculation results of the calculating means. And control means for controlling the aperture areas of the aperture device with a correlation therebetween.

Further, the apparatus is provided with control means for simultaneously controlling the opening areas of the high-pressure side and low-pressure side throttle devices.

[0010] Further, the control means may control the high-pressure side or
And the opening area of the low-pressure side throttle device.

Further, a refrigerant return pipe is provided between the receiver tank and a suction side portion of the compressor, and guides the refrigerant pressure to the compressor while reducing the refrigerant pressure of the receiver tank.

Further, the refrigerant return pipe has one end on the receiver tank side connected to a portion near the upper portion of the receiver tank, and guides the refrigerant gas to the compressor while restricting the refrigerant gas near the upper portion of the receiver tank. .

[0013] Further, a control valve is attached to the refrigerant return pipe, and controls a pressure of the refrigerant gas based on a temperature of refrigerant discharged from the compressor.

Further, the heat exchange means is provided so as to exchange heat between the low-pressure refrigerant sucked into the compressor and one of the high-pressure or medium-pressure refrigerant from the condenser to the low-pressure side expansion device. .

The compressor is provided between any part from the condenser to the low-pressure side throttling device and a part on the suction side of the compressor, and transfers the refrigerant in any part to the suction side of the compressor. A refrigerant return pipe for guiding, a throttle device attached to the refrigerant return pipe, for controlling the pressure of the refrigerant based on the refrigerant temperature discharged from the compressor; a refrigerant controlled by the throttle device; And a heat exchange means for exchanging heat with the heat exchange means.

Further, the overheating detecting means detects the degree of superheating of the refrigerant at the evaporator outlet as the overheating characteristic value.

Further, a refrigeration system according to the present invention comprises: a refrigeration system in which a compressor, a condenser, a high-pressure side expansion device, a receiver tank, a low-pressure side expansion device, and an evaporator are sequentially connected by piping; Supercooling detection means for detecting the degree of supercooling by the condensing pressure of the refrigerant in the condenser of the refrigerating apparatus; superheating detecting means for detecting the degree of superheating by the evaporating pressure of the refrigerant in the evaporator; Control means for correcting the opening areas of the high-pressure side and low-pressure side throttle devices based on the opening area of the side throttle device so as to make each detection result of the supercooling detection means and the overheat detection means close to a target value. Things.

A refrigeration system according to the present invention includes a refrigeration system in which a compressor, a condenser, a high-pressure side expansion device, a receiver tank, a low-pressure side expansion device, and an evaporator are sequentially connected by piping. Intermediate pressure detecting means for detecting the pressure of the refrigerant in the receiver tank, which is an intermediate pressure between the condensation pressure of the refrigerant in the condenser and the evaporation pressure of the refrigerant in the evaporator; and And control means for correcting the opening areas of the high-pressure side and low-pressure side throttle devices so that each detection result of the intermediate pressure detecting means approaches a target value based on the opening area.

A refrigeration system device according to the present invention includes a refrigeration system in which a compressor, a condenser, a high-pressure side expansion device, a receiver tank, a low-pressure side expansion device, and an evaporator are sequentially connected by piping. Supercooling detecting means for detecting a refrigerant discharge temperature of the compressor as a supercooling characteristic value, overheating detecting means for detecting a suction refrigerant temperature of the compressor as a superheat characteristic value, and a current high-pressure side and low-pressure side expansion device Control means for correcting the opening areas of the high-pressure side and low-pressure side expansion devices so that each detection result of the supercooling detection means and the overheating detection means approaches a target value based on the opening area of .

Further, the overheat detecting means detects the degree of superheat of the refrigerant drawn into the compressor as the overheat characteristic value.

Further, the overheat detecting means detects the degree of superheat of the refrigerant at the evaporator outlet as the overheat characteristic value.

Further, at least one of the condenser and the evaporator is provided in parallel, and the high-pressure side restriction device or the low-pressure side restriction device corresponding to each of the condenser or the evaporator provided is provided. Things. Further, the control method of the refrigeration system device according to the present invention, the compressor, a condenser, a high-pressure side expansion device, a receiver tank, a low-pressure side expansion device, and a refrigeration system configured by sequentially connected by piping, The supercooling characteristic value corresponding to the degree of supercooling of the condenser outlet refrigerant of the refrigerating apparatus and the superheating characteristic value corresponding to the degree of superheating of the suction refrigerant of the compressor are detected.
Calculating respective deviation values between a target supercooling characteristic value and a target superheat characteristic value corresponding to an operation state of the refrigerating device; and the subcooling with respect to a current opening area of the high-pressure side and the low-pressure side expansion device. Correcting the amount of change in the opening area from the deviation values of the characteristics and the overheating characteristics, in addition to the opening areas of the high-pressure side and low-pressure side throttle devices, and high-pressure side and low-pressure side throttles disposed on both sides of the receiver tank Controlling the device to the corrected opening area. In addition, the method further comprises a step of controlling the high-pressure side and the low-pressure side expansion devices simultaneously with a correlation therebetween.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Hereinafter, Embodiment 1 of the present invention will be described with reference to FIG.
2 will be described. FIG. 1 is a diagram showing a schematic configuration of a refrigeration system apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 3 denotes a compressor, 5 denotes a four-way valve for changing the flow of refrigerant between cooling and heating, and 12 Is a receiver tank for storing a refrigerant, 14 is a suction pipe, 21 is a condenser for outdoor heat exchange, 22 is an evaporator which is an indoor heat exchanger, and 23 is mounted between the condenser 21 and the receiver tank 12. High-pressure side adjusting means for adjusting the pressure or flow rate (adjusting means located on the high-pressure side of the two-stage throttle in the order of refrigerant flow during cooling operation; hereinafter, abbreviated as high-pressure side throttle device); Adjusting means (lower-stage adjusting means located at the lower stage side of the two-stage throttle during the cooling operation, which is attached between the compressors and adjusts the low pressure or the flow rate of the refrigerant to the evaporator. Abbreviated), 25 is the condenser 21 Pressure detecting means for detecting a force, 26 is a temperature detecting means for detecting an outlet temperature of the condenser 21, 27 is a temperature detecting means for detecting an inlet temperature of the evaporator 22, and 28 is a temperature detecting means for detecting a compressor suction temperature. , 29 are arithmetic units for calculating the characteristic values of the respective refrigerants in the refrigeration cycle from the detection data of each of the detection units 25 to 28, and 30 is the opening area of each adjusting unit 23, 24 based on the calculation result of the arithmetic unit 29. Is a controller that is a control means for controlling. FIG. 2 is a Mollier diagram (temperature / pressure-enthalpy diagram) showing the flow operation of the refrigerant of the present invention, wherein A to E, A 'to E', and D "in the drawing.
Is an affixed to explain the characteristic state value of each refrigerant at each position of the refrigeration cycle.

In the refrigeration system according to the present invention, the refrigerant (state A) sucked into the compressor 3 is
(State B), is condensed by the condenser 21 to become a liquid refrigerant (state C), and is once throttled by the high-pressure side throttle device 23 to slightly reduce the pressure (state D) to the receiver tank 12. Then, it is throttled again by the low-pressure side throttle device 24 (in the state of E), evaporated in the evaporator 22, and sucked into the compressor 3 via the suction pipe 14 (state of A). In the operation of such a refrigeration cycle, for example, the high-pressure side expansion device 23
And the low-pressure side throttle device 24 is controlled to have a certain opening area.
As shown by the solid line, it is assumed that the surplus refrigerant liquid accumulates in the receiver tank 12, and the accumulated liquid level keeps a stable state (solid line in FIG. 2). At this time, the high pressure side throttle device 23
The refrigerant pressure in the flow path including the receiver tank 12 extending from the outlet to the low-pressure side expansion device 24 is a pressure between the condensing pressure (high pressure) and the evaporation pressure (low pressure), that is, a medium pressure, and is saturated in the Mollier diagram. The saturated liquid is located on the liquid line (state d).

The superheat degree of the compressor suction refrigerant is obtained by calculating a deviation value from the temperatures detected by the compressor suction refrigerant temperature detecting means 28 and the evaporator inlet refrigerant temperature detecting means 27, respectively, by the calculator 29. (This deviation value is referred to as the degree of superheat.) The degree of supercooling of the refrigerant at the condenser outlet is determined by the saturation temperature of the refrigerant corresponding to the pressure detected by the condenser refrigerant pressure detecting means 25 and the refrigerant temperature of the condenser outlet refrigerant. A calculator 29 calculates and calculates a difference between the detected temperature and the detected temperature. (Note that this deviation value is called the degree of supercooling.)

The subcooling detecting means for detecting the subcooling characteristic value corresponding to the degree of subcooling of the refrigerant at the outlet of the condenser includes a temperature detecting means 26 for detecting the refrigerant temperature at the outlet of the condenser, a condenser refrigerant pressure detecting means. And a condenser temperature detecting means (not shown) for detecting a temperature near the center of the condenser corresponding to the saturation temperature of the refrigerant corresponding to the detected pressure. The deviation value from the temperature of the outlet refrigerant may be set as the degree of supercooling. The superheat degree detecting means for detecting the superheat characteristic value corresponding to the superheat degree of the refrigerant suctioned into the compressor may be an evaporator outlet temperature detecting means (not shown) for detecting the evaporator outlet refrigerant temperature. And evaporator inlet temperature detecting means (2) for detecting the evaporator inlet refrigerant temperature.
7), and the deviation value of the inlet / outlet temperature of the evaporator may be used as the degree of superheat. That is, since the pressure of the refrigerant is the saturation temperature of the refrigerant, the pressure may be detected instead of the temperature, and the temperature may be detected instead of the pressure.

Here, when the high-pressure throttle device 23 is slightly reduced, the pressure (medium pressure) at the outlet of the high-pressure throttle device 23 decreases,
The refrigerant enters a gas-liquid two-phase state (in the state of "d") and flows into the receiver tank 12. At this time, the receiver tank 1
The gas refrigerant in the upper part due to the action and effect of gravity in 2,
Since the liquid refrigerant is separated at the lower part, if both the inlet pipe and the outlet pipe of the receiver tank 12 are arranged at the lower part of the receiver tank 12, only the liquid refrigerant is always sent to the low-pressure side expansion device 24. Further, due to the gas-liquid two-phase of the refrigerant, the vaporized refrigerant reduces the excess liquid refrigerant in the receiver tank 12 and lowers the liquid level. Then, the liquid refrigerant discharged from the receiver tank 12 during the refrigeration cycle is pushed out and accumulated at the outlet of the condenser 21, so that the degree of supercooling in the refrigeration cycle increases. (C → C 'state).

At this time, since the pressure of the refrigerant is medium pressure, the flow rate of the refrigerant passing through the low-pressure side expansion device 24 decreases, and the degree of superheat of the refrigerant sucked into the compressor 3 also increases (A → A). '). Then, when the refrigerant in the flow path from the outlet of the high-pressure-side expansion device 23 to the low-pressure-side expansion device 24 via the receiver tank 12 has just become a saturated liquid refrigerant (A ′), this change stops, and the refrigeration cycle is stopped. Stabilizes (dashed line in FIG. 2). This is because when the refrigerant crosses the saturated liquid line and a part of the refrigerant is gasified, and the gas refrigerant having a small weight per unit volume is supplied to the low-pressure side expansion device, the refrigerant extremely moves to the evaporator 22 side. No longer supplied, the refrigerant collects on the condenser side, and the collected refrigerant is condensed by the condenser as described above, and becomes an excessively supercooled liquid refrigerant at the outlet thereof. This is because the so-called self-help function of the refrigeration cycle works, in which the refrigerant is then supplied to the evaporator via the receiver tank to constantly balance the amount of the refrigerant in each part in the refrigeration cycle.

In such an operation state in which the gaseous refrigerant is supplied, the degree of supercooling of the refrigerant at the outlet of the condenser 21 changes more than the degree of superheating of the refrigerant sucked into the compressor 3. Such a change occurs when the opening area of the high-pressure throttle device 23 is reduced or when the opening area of the low-pressure throttle device 24 is changed. In other words, when the opening area of the high-pressure-side expansion device 23 or the low-pressure-side expansion device 24 is changed, the amount of refrigerant flowing through each of the adjusting units 23 and 24 changes, and the compressor 3
This is because both the degree of superheating of the suction refrigerant and the degree of supercooling of the refrigerant at the outlet of the condenser 21 change.

Therefore, a deviation value between a target value of the degree of supercooling of the refrigerant at the outlet of the condenser 21 and a target value of the degree of superheating of the refrigerant sucked into the compressor 3 and a measured value or an estimated value thereof is obtained by the calculator 29. Next, a relational expression for associating the obtained deviation value with the change rate of the opening area of the high-pressure side throttle device 23 and the low-pressure side throttle device 24 is created in advance from the theoretical and experimental results, and is stored in the calculator 29. Since the relational expression
Calculates the change rate of the opening area of each of the regulating valves 23 and 24 based on the supercooling degree and the superheat degree deviation value between each of the measured values and each target value calculated as described above. The controller 30 controls the opening areas of the expansion device 23 and the low-pressure side expansion device 24. In this way, both the degree of supercooling of the refrigerant at the outlet of the condenser 21 and the degree of superheating of the refrigerant sucked into the compressor 3 are brought closer to the target values corresponding to the preset operating state of the refrigeration system.

Next, the flow of the processing will be described with reference to the overall flowchart of FIG. 3 showing the overall processing flow, and the normal control of FIG. 4 (the superheat degree of the compressor suction refrigerant and the refrigerant outlet refrigerant indicating the state characteristic value of the refrigeration cycle). The case of controlling the degree of supercooling will be described with reference to a flowchart. First, as shown in FIG. 3, when the operation of the compressor is started (ST1), if the opening areas of the expansion devices 23 and 24 are large (not throttled) after startup, a large amount of refrigerant liquid flows into the compressor. If the compressor pressure is too high (liquid back phenomenon), or if the load on the compressor becomes too large and the compressor breaks down, or if the opening areas of the expansion devices 23 and 24 are small (too small), the evaporation pressure is reduced. In order to avoid cooling and heating capacity dropping due to overdrawing,
An initial starting opening area set in advance from a test result or a calculation result is read from the arithmetic unit 29 (ST2). Next, controller 3
0 enters the start control for controlling the opening areas of the high-pressure side expansion device and the low-pressure side expansion device (ST3).

After that, when the discharge temperature of the compressor becomes higher than the specified temperature (predetermined temperature) (ST4), the above-mentioned start control (ST3) is exited, and the operation state of the system (heating / cooling, multi-room refrigeration system) Depending on the number of indoor units operating in the case of the device, etc.), the state characteristic values of the refrigeration cycle (for example, the degree of superheating of the refrigerant suctioned by the compressor and the degree of supercooling of the refrigerant at the condenser outlet) are set so that the operating efficiency of the system becomes the best. The initial target values of the compressor suction refrigerant superheat degree and the condenser outlet refrigerant supercool degree, which are indications of the refrigerant state quantity of each part obtained from the test result or the calculation result obtained in advance by the test, are called from the computing unit 29. (ST5).

Next, the opening areas of the high-pressure throttle device and the low-pressure throttle device are controlled by the controller 3 so as to reach the called target values.
0 controls (ST6). Then, the normal control (ST7)
After that, as long as the operating state of the system does not change, normal control is repeatedly performed so that the state characteristic value of the refrigeration cycle always remains at the target value even if the outdoor temperature or indoor load state changes. (ST7-ST8). Then, the operation state of the system described in detail below changes (for example,
(Heating / cooling, change in the number of operating indoor units in the case of a multi-room refrigeration system), the flow returns to (ST5) again, and the refrigerant state quantity of each part corresponding to the changed operating state of the system. Target values (degrees of superheat and supercooling) which are guidelines for the above are called from the calculator 29, and controlled so that the opening areas of the high-pressure side and the low-pressure side expansion device corresponding to the called target values are obtained, and the operation of the system is performed. If the state does not change, the control is repeated (ST7 to ST8).

Next, the normal control flow will be described in detail with reference to FIG. Normal control (FIG. 4 showing ST7 in FIG. 3)
First, the process waits for a certain period of time (S
T7a). This is because if the control is performed immediately after changing the opening area of the adjusting means, the system will hunt (the flow rate and pressure of the refrigerant flowing in the cycle will rapidly increase and decrease, and each control device will not be able to follow this sudden increase or decrease. Occurs), and the balance of the refrigeration cycle is lost. This is because stable operation control cannot be performed. Therefore, for example, a stable control operation can be obtained by controlling each device after waiting for about 3 minutes until the refrigerant flow rate and pressure settle down.

Thereafter, a deviation value between the measured or estimated compressor suction refrigerant superheat degree and condenser outlet refrigerant supercooling degree and their respective target values is calculated by the calculation means (ST7).
b). Then, using a relational expression created from a theory or an empirical result that associates the deviation value of the superheat degree of the refrigerant suctioned by the compressor / the supercooled degree of the refrigerant at the condenser outlet with the opening area change amount of the high-pressure / low-pressure throttle device, and Calculated compressor superheat degree
The amount of change in the opening area of the high-pressure / low-pressure side throttle device is determined so that the deviation between the target value and the measured value of the degree of subcooling of the refrigerant at the outlet of the condenser approaches zero.

Next, the obtained opening area change amount is added to the current opening area of each adjusting means, and the opening area of each of the high-pressure side and low-pressure side throttling devices is calculated. Since the output is provided to the controller 30, the controller 30 controls the opening areas of the respective regulating valves 23 and 24 based on the output result (ST7c). As a result of this control, the loop is repeated until the measured superheat degree and supercool degree both reach the target values, that is, the deviation value becomes zero (ST7 to ST7).
9). However, as described in FIG. 3, when a change occurs in the operation state of the system (change in the number of operating indoor units in the case of a heating / cooling system or a multi-room refrigeration system device) during the control (ST5). Then, the process exits the normal control and returns to ST5 in FIG.

As described above, while repeating each of these steps (ie, looping each step), the state characteristic values of the refrigeration cycle (for example, the degree of superheating of the refrigerant sucked into the compressor and the degree of subcooling of the refrigerant at the condenser outlet) are changed. Since the control is performed to achieve the target value, the operation efficiency is very good, and an economical refrigeration system can be obtained. In addition, because the high-pressure side and low-stage side adjustment means are controlled based on theoretical or empirical formulas, the operating state of the system can be stabilized in a short time, and the annual average efficiency is significantly improved compared to the past. Therefore, an economical and highly reliable refrigeration system device can be obtained.

Next, it was created on the basis of theory and empirical rules for associating deviation values of the degree of superheating of the refrigerant suctioned by the compressor and the degree of supercooling of the refrigerant at the outlet of the condenser with the change in the opening area of the high-pressure side and low-pressure side expansion devices. The relational expression will be specifically described. Normally, when the refrigerant is flowing in the pipe and there is a throttle in the pipe, by applying the momentum conservation formula of the refrigerant before and after the throttle,
When the pressure difference before and after the throttle is ΔP, the density of the fluid is ρ, the opening area of the throttle is S ₂ , and the proportional constant is k, the mass flow rate G of the refrigerant
Is obviously expressed as the following equation (1). G = k · √ (ρ) · S ₂ · √ (△ P) (1) Here, the high-pressure side adjusting means and the low-pressure side adjusting means are throttle devices installed in the piping, and each throttle is Equation (1) holds before and after.

Further, since the mass flow rates of the refrigerant flowing through the high-pressure side throttle device and the low-pressure side throttle device are clearly equal, the opening areas of the refrigerant are S _H and S _L , the condenser pressure is P _H , and the intermediate pressure is P _{H. M} , the evaporator pressure is P _L , the proportionality constant is k ₁ ,
Placing a k _3, to both the high pressure side and low pressure side throttle device (1)
Expressions can be applied. Further, since the change in the density of the refrigerant can be almost neglected in a simple manner, the following equations (2) and (3) hold (the value of the mass flow rate obtained by ignoring the change in the density also increases or decreases). Since the tendency is the same as the density change, the effect on the calculation result can be almost ignored.) G = k ₁ · S · _H (P _H -P _M ) (2) G = k ₃ · S _L · √ (P _M -P _L ) (3)

When this is expanded, the following two equations are obtained. √ (P _H -P _M ) = G / (k ₁ · S _H ) (4) √ (P _M -P _L ) = G / (k ₃ · S _L ) (5) G, k _3, k ₁ to clear the, dividing equation (5) with (4), since _{k 1 ≒ k 3, √ (} P M -P L) / √ (P H -P M ) ≒ S _H / S _L = C ₁ ∴C ₁ = S _H / S _L (6)

In order to obtain P _H -P _L , 2
Taking the sum of the power and the square of equation (5), the following equation holds. (1) ² : P _H -P _M = G ² / (k ₁ · S _H ) ² (2) ² : P _M -P _L = G ² / (k ₃ · S _L ) ² ∴P _H -P _L = G ² · {1 / (k ₁ · S _H ) ² + 1 / (k ₃ · S _L ) ² } ≒ (G ² / k ₁ ² ) · (1 / _SH ² + 1 / S _L ² ) = C _{2 ∴C 3 = 1 / S H} 2 + 1 / S L 2 ··· (7)

Now, the meaning of the derived equations (6) and (7) will be considered from the derivation process. First, (7) C ₂ in, i.e., be said to the C ₃ constant, the difference between the condenser pressure P _H evaporator pressure P _L it is indicative that a constant, (7) Area S of the high-pressure side throttle device based on
Changing _H and the opening area S _L of the low-pressure side throttle device means that P _H and P _L corresponding to each of the changed opening areas are determined without any modification.

Accordingly, under the condition that the opening areas S _H and S _L are kept constant and P _H and P _{L in the} equation (7) are kept constant, (C ₂ and C ₃ are also described above. which is constant as.), setting the medium-pressure P _M (6) C ₁ is uniquely determined from the equation. Further, that the value of P _M corresponds uniquely to the refrigerant storage quantity of the receiver tank, since it is a self-evident, (6) and (7) the opening area S _H based on the equation, S By controlling _L , eventually, P _H , P _L ,
P _M, and it means that the control of the refrigerant storage quantity in the receiver tank. Note that simply replacing equation (7) with C ₃ = 1 / S _H + 1 / S _L (7) ′ and performing control based on equations (6) and (7) ′ does not matter. No problems have been confirmed by tests and simulations.

Next, the refrigerant suction refrigerant heating degree (hereinafter abbreviated as SH) and the condenser outlet refrigerant supercooling degree (hereinafter SC) will be described.
(Abbreviated as “.”), And to perform these controls, it is necessary to relate these equations (6) and (7). The following can be said from equations (6) and (7). (1) increasing the C ₁ increases the S _H, ie, whether to reduce the SC, or to reduce the S _L.
That is, it is equivalent to increasing SH. (2) a C ₃ to increase decreases the S _H, i.e. either by increasing SC, or to reduce the S _L.
That is, it is equivalent to increasing SH. From these results, define the C ₁ 'and C _3' as follows, the knowledge about be associated respectively with C ₁ and C _3, C ₁ and _{C 3 (1), (2} ) formula The same can be said for C ₁ ′ and C ₃ ′. That, C ₁ 'is large than (is C ₁ becomes C ₁ when smaller' also decreases) when the C ₁ becomes large, 'when it becomes larger (C ₃ smaller C _3' C ₃ when the C ₃ becomes larger Smaller).

As described above, C ₁ ′ and C ₃ ′ are defined as follows. C ₁ ′ = (SH + 10) / (SC + 10) (8) C ₃ ′ = SH + SC (9) The apparent numerical value 10 in the equation (8) is C ₁ ′ → when SC → 0. This is for preventing the occurrence of ∞, and does not impair the generality of the expression (these expressions hold even if the numerical value is, for example, 5 or 15). However,
The speed or manner of convergence to the control target value differs depending on the numerical value, and the optimum value of the numerical value differs depending on the system. In the system assumed this time, when the numerical value is 10, the system does not go too far with respect to the target, the speed of approaching the target is not too slow, and the system is optimally controlled.

Next, the above equations (6), (7), (8),
The control is performed using (9), and the actual calculation method (that is, ST7b and ST7c in FIG. 4) will be described with reference to the flowchart in FIG. It should be noted that the flowchart of FIG. 5 corresponds to ST7b and ST7c of the flowchart of FIG.
Is described in detail. First, the current value (detected value) of the superheat degree of the compressor suction refrigerant is SH, and the target value of the control is SH.
^* The current value (detected value) of the subcooling degree of the refrigerant at the outlet of the condenser is S
C, the control target value is set as SC ^* .

From the above equations (8) and (9), C ₁ ′, C ₃ ′ and C ₁ ′ ^* and C ₃ ′ ^* as control target values at this time are calculated as follows (ST10). ). _{C 1 '= (SH + 10} ) / (SC + 10) C 3' = SH + SC C 1 '* = (SH * +10) / (SC * +10) C 3' * = SH * + SC * Also, the current of the high-pressure side throttle device Since the opening area S _H and the opening area SL of the low-pressure-side diaphragm device are known, the current C ₁ and C ₃ are obtained using the equations (6) and (7) as follows (ST20). C ₁ = S _H / S _L C ₃ = 1 / S _H ² + 1 / S _L ²

Next, E and F are proportional constants determined by tests or simulations, and ΔC ₁ and ΔC ₃
Is defined as the following equation (ST30). ΔC ₁ = E · (C ₁ ′ ^* −C ₁ ′) (10) ΔC ₃ = F · (C ₃ ′ ^* −C ₃ ′) (11) At this time, the following equation is used. C ₁ and C ₃ of the new time (denoted C ₁ ^N and C ₃ ^N , respectively) can be computed (S
T40). C ₁ ^N = C ₁ + ΔC ₁ (12) C ₃ ^N = C ₃ + ΔC ₃ (13) Then, C ₁ ^N and C ₃ are added to the expressions (6) and (7). By substituting ^N , these expressions are back-calculated to calculate S _H and S _L at the new time (ST50), so that the opening areas of the high-pressure side restriction device and the low-pressure side restriction device become S _H and S _L , respectively. Then, the controller 30 outputs a control command to each of the aperture devices 23 and 24 (ST60).

As described above, in the present embodiment,
The superheat degree (SH) of the refrigerant sucked into the compressor and the supercooling degree (SC) of the refrigerant at the condenser outlet are detected, and the calculation of the equations (8) and (9) is performed based on the state characteristic values of these two refrigeration cycles. When done, two values of C ₁ ′ and C ₃ ′ are calculated. Then, these (6) and (7) (or (7) 'formula) and _{C 1} and C _3, defined in (10) -
These are uniquely associated with each other by the expression (13), and these are calculated, and further, the expressions (6) and (7) (or the expression (7) ′) are inversely calculated using the calculated C ₁ and C _3. , The opening area (S _H ) of the high-pressure side throttle device and the opening area (S _L ) of the low-pressure side throttle device are simultaneously calculated, and the two adjusting means are controlled based on the calculation results. As described above, according to the present invention, the two adjusting means on the high-pressure side and the low-stage side are controlled so as to be correlated with each other based on the two characteristic values of the refrigerant.

Here, the explanation has been given by taking as an example the case where there are two refrigerant state characteristic values and two adjusting means in the refrigeration cycle. However, these are not necessarily two. One, two adjustment means
One. Or, the refrigerant state characteristic value and the adjusting means are each four or the like,
The same is true for any combination.

The adjusting means (throttle device) for adjusting the pressure or the flow rate in the present invention includes, for example, an electronic expansion valve, a constant pressure expansion valve, a pneumatic expansion valve, switching of several capillary tubes, etc. Flow resistance (opening area)
Anything can be used as long as it can be changed.

In order to make the whole of the present invention easy to understand, the control of the opening area of the high-pressure throttle device and the low-pressure throttle device has been described. On the other hand, using a throttle device such as a constant-pressure expansion valve in which the back pressure is substantially constant, or a throttle device such as a capillary tube in which the pressure of one of the inlet and outlet is determined when the other pressure is determined, the condenser outlet refrigerant is used. Needless to say, the opening area may be controlled so that the characteristic value of only one of the supercooling degree and the superheating degree of the compressor suction refrigerant becomes a predetermined value.

In addition, by detecting either the degree of supercooling or the degree of superheating in which the opening area is not controlled, and utilizing this detection result, the above-mentioned electronic type can be used without using the constant pressure type expansion valve. Control can also be performed using an expansion valve, a capillary tube, or the like. At this time, a target superheat characteristic value table corresponding to the operation state of the refrigeration apparatus and the degree of supercooling (back pressure) or a target supercool characteristic value table corresponding to the operation state of the refrigeration apparatus and the degree of superheat (back pressure) Must be obtained from an experiment or theoretical calculation formula, created and input to the computing unit 29 and the like.

The present invention is also applicable to each case of the refrigeration system having the configuration shown in FIGS. In these refrigeration system devices, the following effects can be expected in addition to the effects described above.

First, as shown in FIG. 6, a refrigerant return pipe 31 for returning the liquid refrigerant near the lower part of the receiver tank to the suction side of the compressor was provided, and the liquid refrigerant in the receiver tank was returned to the suction side of the compressor. In the configuration, in order to lower the refrigerant discharge temperature of the compressor and increase the refrigerant suction amount of the compressor,
In particular, a highly reliable refrigeration system device that improves the heating capacity and prevents deterioration of the refrigerant and the lubricating oil can be obtained. In addition,
At this time, the refrigerant return pipe 31 restricts the liquid refrigerant from the inside of the receiver tank by the resistance of the pipe and supplies the liquid refrigerant to the suction side of the compressor.

As shown in FIG. 7, a refrigerant return pipe 31 for returning the liquid refrigerant near the lower part of the receiver tank to the suction side of the compressor is provided, and a control valve 32 is provided in the refrigerant return pipe 31. Is controlled by the temperature of refrigerant discharged from the compressor (liquid injection).
A highly reliable refrigeration system that can maintain the discharge refrigerant temperature at a predetermined temperature and increase the suction pressure (refrigerant amount) of the compressor, thereby improving the heating capacity and preventing deterioration of the refrigerant and lubricating oil. Is obtained.

As shown in FIG. 8, a refrigerant return pipe 31 for returning the gas refrigerant near the upper portion of the receiver tank to the suction side of the compressor is attached, and the gas refrigerant in the receiver tank is returned to the suction side of the compressor. In the case of the configuration diagram (gas injection), the temperature of the refrigerant discharged from the compressor is reduced while preventing the liquid refrigerant from returning to the compressor, and the suction pressure (refrigerant amount) of the compressor is increased. In addition, it is possible to obtain a highly reliable refrigeration system device in which the heating capacity is improved while preventing the liquid back of the refrigerant and the deterioration of the refrigerant and the lubricating oil is prevented. At this time, the refrigerant return pipe 31 throttles the gas refrigerant in the receiver tank by the resistance of the pipe and supplies it to the suction side of the compressor.

As shown in FIG. 9, a refrigerant return pipe 31 for returning the gas refrigerant near the upper part of the receiver tank to the suction side of the compressor is provided, and a control valve 32 is provided in the refrigerant return pipe 31. In the configuration diagram in which the opening degree of the compressor is controlled by the refrigerant temperature discharged from the compressor (gas injection), the discharge refrigerant temperature is maintained at a predetermined temperature while always supplying the optimal refrigerant amount to the compressor, and the suction of the compressor is performed. Since the pressure (refrigerant amount) is increased, in particular, a highly reliable refrigeration cycle device in which the heating capacity is improved and the deterioration of the refrigerant and the lubricating oil is prevented is obtained.

Further, as shown in FIG. 10, any part from the condenser to the low-pressure side throttle device, that is, the medium-pressure liquid refrigerant (or high-pressure liquid refrigerant) and the low-pressure gas refrigerant (which is sucked into the compressor) In the configuration diagram in the case where the heat exchange means 33 for exchanging heat with the refrigerant gas is provided, the refrigerant having a large degree of supercooling is supplied to the evaporator and the gas refrigerant is always supplied to the compressor. A highly reliable refrigeration cycle device with improved cooling capacity and prevented liquid back can be obtained.

Further, as shown in FIG. 11, a refrigerant return pipe for returning any part from the condenser to the low-pressure side throttle device, that is, the medium-pressure liquid refrigerant (or the high-pressure liquid refrigerant) to the suction side of the compressor. 34, and a throttling device 3
6, a heat exchange means 35 for exchanging heat between the refrigerant passing through the expansion device 36 and the medium-pressure liquid refrigerant (or high-pressure liquid refrigerant).
In the configuration in which the refrigerant is supplied, the discharge refrigerant temperature is maintained at a predetermined temperature while supplying the optimum refrigerant amount to the compressor, the suction pressure (refrigerant amount) of the compressor is increased, and the refrigerant having a large supercooling degree is provided. Is supplied to the evaporator, and in particular, a highly reliable refrigeration cycle device that improves the cooling capacity and prevents deterioration of the refrigerant and the lubricating oil can be obtained.

What has been described above is explained in the second embodiment described later.
The same applies to 8.

Embodiment 2 FIG. 12 is a flowchart showing the normal control according to the second embodiment of the present invention. The configuration of this apparatus is the same as that of FIG. 1, and the overall flowchart is the same as that of FIG. Further, in the refrigeration system apparatus of the second embodiment, the opening areas of the high-pressure side and low-pressure side expansion devices are controlled using the evaporator outlet refrigerant superheat degree and the condenser outlet refrigerant supercooling degree as target values. Procedures and effects are almost the same as those of the first embodiment,
As the SH and SC values to be inserted into the equations (8) and (9), the superheat degree of the evaporator outlet refrigerant temperature and the supercooling degree of the condenser outlet refrigerant are used as reference values. That is, the first embodiment
In the above, the difference between the evaporator inlet refrigerant temperature and the compressor inlet refrigerant temperature was used as the reference value of the superheat (SH). In the second embodiment, however, the difference between the evaporator inlet refrigerant temperature and the evaporator outlet refrigerant temperature was determined. The deviation value is used as a reference value of the degree of superheat (SH).

In this way, in order to accurately control the degree of superheating of the refrigerant at the outlet of the evaporator, the cooling capacity is maintained during cooling, and the temperature of the discharged refrigerant gas is increased by radiating heat from the suction pipe during heating. In particular, a refrigeration system device with improved heating capacity can be obtained.

Embodiment 3 FIG. 13 is a flowchart showing the normal control according to the third embodiment of the present invention. The configuration of the apparatus is the same as that of FIG. 1, and the overall flowchart is the same as that of FIG. In the refrigeration system of the third embodiment, the evaporating pressure as a superheat characteristic value corresponding to the degree of superheating of the refrigerant sucked into the compressor and the condensation as the supercooling characteristic value corresponding to the degree of supercooling of the refrigerant at the outlet of the condenser. The low-pressure-side and high-pressure-side expansion devices are controlled using the pressure as a target value. The specific procedure and operation and the operation and effect thereof are almost the same as those of the first embodiment. Equations (8) and (9) Instead of SH and SC inserted in the equation, the evaporation pressure and the condensation pressure, or the saturation evaporation temperature and the saturation condensation temperature of the refrigerant corresponding to those pressures are replaced.
(Note that an evaporating pressure detecting means as an overheating detecting means for measuring an evaporating pressure and a condensing pressure detecting means as a supercooling detecting means for measuring a condensing pressure are not shown.)

At this time, the calculating means 29 calculates a deviation value between each detection result of the evaporating pressure and the condensing pressure detecting means and the target evaporating pressure and the target condensing pressure corresponding to the operation state of the refrigeration system. Based on the result, the control means 30 controls the opening areas of the high-pressure side and low-pressure side throttle devices.
In addition, at this time, each R in a capacity of a compressor, an evaporator, a condenser, and the like, which is preliminarily designed and uniquely determined (that is, a refrigeration apparatus in which the correlation between the respective abilities is uniquely determined) is set.
Relationship between evaporation pressure and condensation pressure for T (room temperature) and AT (outside air temperature), and evaporation pressure (evaporation saturation temperature) and SH, condensation pressure (condensation saturation temperature) and SC in this relationship
It goes without saying that the relationship with is determined in advance. In this case, an economical and highly reliable refrigeration system device in which hunting is prevented with a small number of components can be obtained.

Embodiment 4 FIG. 14 is a flowchart showing the normal control according to the fourth embodiment of the present invention. The configuration of the apparatus in this flowchart is the same as that in FIG. 1, and the entire flowchart is the same as FIG. Further, in the refrigeration system apparatus according to the fourth embodiment, the opening areas of the high-pressure side and the low-pressure side expansion devices are controlled using the receiver tank pressure (intermediate pressure) as a target value. The operation and effect are almost the same as those of the first embodiment, except that the evaporation pressure (low pressure) and the condensation pressure (high pressure) corresponding to the above-mentioned intermediate pressure are set in advance by the above-described equations, and are set. The opening areas of the high-pressure side and low-pressure side throttle devices are controlled so that the evaporating pressure and the condensing pressure are adjusted. That is, instead of SH and SC inserted in the equations (8) and (9), the pressure is simply replaced by the receiver tank pressure. (The means for measuring the receiver tank pressure is not shown.) At this time, the calculating means 29 calculates a deviation value between the measured intermediate pressure and the target intermediate pressure, and from this calculation result, the evaporating pressure. And a deviation value between the detection result of the condensing pressure and the target evaporation pressure and the target condensing pressure corresponding to the operation state of the refrigerating apparatus.

Controlling the receiver tank pressure to a certain target value means controlling the opening areas of the high-pressure side and low-pressure side expansion devices to control the amount of refrigerant in the receiver 12 to the target value. As a result, the amount of each refrigerant in the condenser and the evaporator is controlled. Further, as described above, controlling the amount of refrigerant in each of these devices means that SH and SC are eventually controlled as described above. Therefore, instead of the controller 30 controlling the opening areas of the high-pressure side and the low-pressure side throttling device based on the deviation value between the actual measurement value of SH and SC and the target value, the actual measurement value and the target value of the receiver tank pressure are compared with the control values. It is needless to say that the same effect as that of the first embodiment can be obtained even if the control is performed based on the deviation value of.

Further, a target value of the receiver tank pressure is set in advance corresponding to the outside air temperature, and if the set target value is used, the control accuracy is further improved, and the economical refrigeration cycle operation is maintained. Needless to say, this is obtained. The target value is set in advance in accordance with the outside air temperature, and the control accuracy is further improved by using the set target value in the other embodiments other than the fourth embodiment. is there. Further, this outside air temperature is set in a predetermined temperature range as one of the operation states of the refrigeration system device. In this way, stable control can be performed even if the outside air temperature changes every moment.

Embodiment 5 FIG. 15 is a flowchart showing the normal control according to the fifth embodiment of the present invention. The configuration of the apparatus is the same as that of FIG. 1, and the overall flowchart is the same as that of FIG. In the refrigeration system apparatus according to Embodiment 5, the opening areas of the low-pressure side and high-pressure side throttle devices are determined based on the deviation between the measured values of the compressor discharge refrigerant temperature and the compressor intake refrigerant temperature and the target values. The specific procedure and operation are almost the same as those in the first embodiment, and SH and SC inserted in the equations (8) and (9) are used.
Is inserted in place of the deviation value of the difference between the refrigerant discharge temperature of the compressor and the refrigerant suction temperature of the compressor. (Note that the discharge temperature detecting means, which is the supercooling detecting means for measuring the refrigerant discharge temperature of the compressor, is not shown. The temperature detecting means 28 for detecting the compressor suction refrigerant temperature is the supercooling detecting means. In this case, since the compressor discharge temperature having the highest temperature in the refrigeration cycle is constantly controlled to the target value, hunting can be performed with a small number of components while preventing deterioration of the refrigerant and oil. An economical and highly reliable refrigeration system device which is prevented is obtained.

Further, the target values of the compressor discharge refrigerant temperature and the compressor intake refrigerant temperature are set in advance in correspondence with the outside air temperature, and if the set target values are used, the control accuracy is further improved and economical efficiency is improved. It goes without saying that a control device for maintaining the refrigeration cycle operation can be obtained.

Embodiment 6 FIG. FIG. 16 is a flowchart showing the normal control according to the sixth embodiment of the present invention. The configuration of the apparatus is the same as in FIG. 1, and the overall flowchart is the same as in FIG. In the refrigeration system device according to the present invention, the high-pressure side and low-pressure side expansion devices are controlled based on a deviation value between a measured value of the compressor discharge temperature and a superheat degree of the refrigerant suctioned by the compressor and a target value. The procedure and the effect are almost the same as those of the first embodiment. Instead of the SH and SC deviation values inserted in the equations (8) and (9),
This is simply replaced by the deviation values of the compressor discharge temperature and the compressor superheat degree. (The discharge temperature detecting means, which is the overheat detecting means for measuring the compressor discharge temperature,
Not shown. )

In this case, since the compressor discharge temperature having the highest temperature in the refrigeration cycle is always controlled to the target value, hunting is prevented with a small number of components while preventing deterioration of the refrigerant and oil. Thus, an economical and highly reliable refrigeration system device can be obtained.

Further, target values of the compressor discharge temperature and the compressor suction refrigerant superheat degree are set in advance in correspondence with the outside air temperature.
When the set target value is used, it goes without saying that a control device with further improved control accuracy and economical refrigeration cycle operation can be obtained.

Embodiment 7 FIG. 17 is a flowchart showing the normal control according to the seventh embodiment of the present invention. The configuration of the apparatus is the same as in FIG. 1, and the overall flowchart is the same as in FIG. In the refrigeration system apparatus according to the seventh embodiment, the opening areas of the high-pressure side and low-pressure side expansion devices are controlled using the compressor discharge temperature and the evaporator outlet refrigerant superheat degree as target values. The operation and its effect are almost the same as those of the first embodiment. Instead of the SH and SC deviation values inserted in the equations (8) and (9), the compressor discharge temperature and the evaporator outlet refrigerant superheat degree are used. Is replaced by the standard deviation value. Means for measuring the compressor discharge temperature and the evaporator outlet refrigerant superheat degree is not shown.

Embodiment 8 FIG. FIG. 18 is a diagram showing a configuration of a refrigeration system device according to Embodiment 8 of the present invention.
Is a compressor, 5 is a four-way valve, 12 is a receiver tank, 14 is a suction pipe, 21a and 21b are condensers, 22a and 2
2b is an evaporator, 23a and 23b are installed between the condenser and the receiver tank, and high-pressure side adjusting means (high-pressure side throttle device) for adjusting the pressure of the receiver tank and the flow rate of the refrigerant flowing into the receiver tank, and 24a and 24b are receivers Installed between tank and evaporator, low pressure and evaporator 21
adjusting means (low-pressure side throttling device) on the lower stage for adjusting the flow rate of the refrigerant flowing through a and b, 25 includes condensers 21a and 21b
Pressure detecting means for detecting each pressure of the pressure, 26a and 26b
Are temperature detecting means for detecting the outlet temperatures of the condensers 21a and 21b, respectively, and 27a and 27b are the evaporator 2 respectively.
Temperature detecting means for detecting the inlet temperature of 2a, 22b, 28
Is a temperature detecting means for detecting the compressor suction temperature, 29 is an arithmetic unit, and 30 is a controller.

In the refrigeration system apparatus according to the eighth embodiment, the values described in the first to seventh embodiments are used as control targets, and the sum of the opening areas of the high-pressure side expansion devices and the opening area of each low-pressure side expansion device are set. Since the sum is controlled and the specific configuration, procedure, and operation are almost the same as those described in the first to seventh embodiments, the description is omitted. In FIG. 11, two condensers and two evaporators are mounted, but the combination of the number of condensers and evaporators is, for example, one and two, one and three, and two, respectively. It is clear that the same holds true for a combination of one, three, one, etc., and such a combination can be used.

Further, in this embodiment, the opening area of each high-pressure side expansion device and the opening area of each low-pressure side expansion device, that is, the sum of the respective opening areas, is controlled. Adjustment means 23a, 2 attached to
The method of allocating the opening areas of 3b, 24a, and 24b, that is, the control of the distribution (opening area) of the refrigerant amount to each condenser or evaporator, is performed by, for example, distributing and controlling according to the ambient temperature of each condenser and evaporator. Alternatively, the control is divided and controlled according to the degree of supercooling of each condenser and the degree of superheating of the evaporator.

As described above, in the eighth embodiment, at least one of the condenser and the evaporator is provided in parallel, and the high pressure or the high pressure corresponding to each of the provided condenser or evaporator is provided. The opening area of the low-pressure side throttling device is calculated by the calculating means control means, and the deviation between each detection result of the supercooling detection means and the overheating detection means and the target supercooling characteristic value and the target superheating characteristic value corresponding to the operation state of the refrigerating apparatus. Values are calculated from the values, and the control means controls the calculation results. Therefore, a highly reliable and easy-to-use refrigeration system device that can easily and accurately prevent hunting can be obtained.

As described above, according to the present invention, the refrigeration cycle operation efficiency is always maintained optimally during the stable operation, and even if the operation state of the refrigeration system changes, the refrigeration cycle of the optimum operation efficiency can be maintained in a short time. An economical and reliable refrigeration system device that can stabilize the cycle and significantly improve the average annual efficiency is obtained.

The change in the operating state of the refrigeration system device includes, for example, the following. (1) Switching the number of indoor units (evaporator or condenser) in a multi-air conditioner (2) Switching the number of compressors of a device with multiple compressors (3) Compressor of a device with a compressor rotation speed control function Change in rotation speed (4) Change in ambient temperature of heat exchanger such as indoor temperature or outdoor temperature (5) Change in area of heat exchanger where refrigerant or air flows in simultaneous cooling / heating multi air conditioner (6) Defrosting operation to heating operation Changes in operating conditions, such as when returning, and changes in refrigerant flow

[0081]

Since the present invention is configured as described above, it has the following effects.

The refrigeration system apparatus according to the present invention comprises a refrigeration system in which a compressor, a condenser, a high-pressure side expansion device, a receiver tank, a low-pressure side expansion device, and an evaporator are sequentially connected by piping. Supercooling detection means for detecting a supercooling characteristic value corresponding to the degree of supercooling of the refrigerant at the outlet of the condenser of the device; superheating detection means for detecting a superheating characteristic value corresponding to the degree of superheating of the suction refrigerant of the compressor; Control for correcting the opening areas of the high-pressure side and low-pressure side expansion devices so that each detection result of the supercooling detection means and the overheat detection means approaches the target value based on the opening areas of the high-pressure side and low-pressure side expansion devices. Means, the operation efficiency is very good,
An effect is obtained that an economic refrigeration system device can be obtained.

A refrigeration system in which a compressor, a condenser, a high-pressure-side expansion device, a receiver tank, a low-pressure-side expansion device, and an evaporator are sequentially connected by piping, and supercooling of refrigerant at the condenser outlet of the refrigeration system. Supercooling detecting means for detecting a supercooling characteristic value corresponding to the temperature, superheat detecting means for detecting a superheat characteristic value corresponding to the degree of superheating of the suction refrigerant of the compressor, and the supercooling detecting means and the superheat detecting means. Calculating means for calculating each deviation value between each detection result and a target supercooling characteristic value and a target superheating characteristic value corresponding to the operation state of the refrigeration apparatus; and the high-pressure side and the low-pressure side based on the calculation results of the calculating means. And control means for controlling the aperture areas of the aperture devices in a manner correlated with each other, so that the operating state of the system can be stabilized in a short time, and the annual average efficiency is greatly improved compared to the conventional one. Bets for can, high refrigeration system unit economical and reliability.

Also, since the control means for simultaneously controlling the opening areas of the high-pressure side and low-pressure side throttle devices is provided, an effect of stabilizing the operation state of the system in a short time is exhibited.

Further, since the control means controls the opening area of the high-pressure side or the low-pressure side expansion device a predetermined time after the operation state of the refrigeration system changes, a highly reliable refrigeration cycle device further preventing hunting. Is obtained.

Further, a refrigerant return pipe is provided between the receiver tank and the suction side of the compressor, and guides the refrigerant to the compressor while reducing the refrigerant pressure in the receiver tank. In order to increase the amount of refrigerant sucked into the compressor, it is possible to obtain a highly reliable refrigeration system device in which the heating capacity is particularly improved and deterioration of the refrigerant and lubricating oil is prevented.

The refrigerant return pipe has one end on the receiver tank side connected to a portion near the upper portion of the receiver tank, and guides the refrigerant gas to the compressor while restricting the refrigerant gas near the upper portion of the receiver tank. In order to lower the discharge refrigerant temperature and increase the suction pressure (refrigerant amount) of the compressor while supplying the refrigerant to the compressor, in particular, to improve the heating capacity while preventing the liquid back of the refrigerant, A highly reliable refrigeration system device that prevents deterioration of the refrigeration system can be obtained.

Further, since the control valve is attached to the refrigerant return pipe and controls the pressure of the refrigerant gas based on the temperature of the refrigerant discharged from the compressor, the discharge refrigerant temperature is controlled to a predetermined value while supplying the optimum amount of refrigerant to the compressor. Since the temperature is maintained and the suction pressure (refrigerant amount) of the compressor is increased, a highly reliable refrigeration cycle device in which the heating capacity is particularly improved and deterioration of the refrigerant and lubricating oil is prevented is obtained.

Further, since the heat exchange means is provided for exchanging heat between the low-pressure refrigerant sucked into the compressor and either the high-pressure or medium-pressure refrigerant from the condenser to the low-pressure side expansion device, the degree of supercooling is reduced. Is supplied to the evaporator and the refrigerant gas is supplied to the compressor, so that a highly reliable refrigeration cycle device with particularly improved cooling capacity and preventing liquid back can be obtained.

Further, a refrigerant return pipe is provided between any part from the condenser to the low-pressure side throttle device and the suction side part of the compressor, and the refrigerant in any one of the above parts is sent to the suction side of the compressor. A guide device is attached to the refrigerant return pipe to control the pressure of the refrigerant based on the refrigerant temperature discharged from the compressor, and the heat exchange means exchanges heat between the controlled refrigerant and the refrigerant at any one of the portions. Therefore, while supplying the optimum amount of refrigerant to the compressor, the discharge refrigerant temperature is maintained at a predetermined temperature to increase the suction pressure (refrigerant amount) of the compressor, and a refrigerant having a large degree of supercooling is supplied to the evaporator. Therefore, it is possible to obtain a highly reliable refrigeration cycle device in which the cooling capacity is particularly improved and the deterioration of the refrigerant and the lubricating oil is prevented.

Since the overheat detecting means detects the degree of superheat of the refrigerant at the outlet of the evaporator as the overheat characteristic value, during the cooling,
Since the cooling capacity is maintained and the temperature of the discharged refrigerant gas is increased by radiating heat from the suction pipe during heating, an economical refrigeration system device with particularly improved heating capacity can be obtained.

The refrigeration system according to the present invention includes a refrigeration system in which a compressor, a condenser, a high-pressure side expansion device, a receiver tank, a low-pressure side expansion device, and an evaporator are sequentially connected by piping. Supercooling detection means for detecting the degree of supercooling by the condensing pressure of the refrigerant in the condenser of the refrigerating apparatus; superheating detecting means for detecting the degree of superheating by the evaporating pressure of the refrigerant in the evaporator; Control means for correcting the opening areas of the high-pressure side and low-pressure side throttle devices based on the opening area of the side throttle device so as to make each detection result of the supercooling detection means and the overheat detection means close to a target value. Therefore, an economical and highly reliable refrigeration system device in which hunting is prevented with a small number of components can be obtained.

The refrigeration system apparatus according to the present invention includes a refrigeration apparatus in which a compressor, a condenser, a high-pressure side expansion device, a receiver tank, a low-pressure side expansion device, and an evaporator are sequentially connected by piping. Intermediate pressure detecting means for detecting the pressure of the refrigerant in the receiver tank, which is an intermediate pressure between the condensation pressure of the refrigerant in the condenser and the evaporation pressure of the refrigerant in the evaporator; and Control means for correcting the opening areas of the high-pressure side and low-pressure side expansion devices so that each detection result of the intermediate pressure detecting means approaches a target value based on the opening area. Thus, an economical and highly reliable refrigeration system device can be obtained.

Further, the refrigeration system according to the present invention comprises a refrigeration system in which a compressor, a condenser, a high-pressure side expansion device, a receiver tank, a low-pressure side expansion device, and an evaporator are sequentially connected by piping. Supercooling detecting means for detecting a refrigerant discharge temperature of the compressor as a supercooling characteristic value, overheating detecting means for detecting a suction refrigerant temperature of the compressor as a superheat characteristic value, and a current high-pressure side and low-pressure side expansion device Control means for correcting the opening areas of the high-pressure side and low-pressure side expansion devices so that each detection result of the supercooling detection means and the overheating detection means approaches a target value based on the opening area of the refrigeration unit. It is economical to constantly control the compressor discharge temperature, which is the highest temperature in the cycle, to prevent deterioration of refrigerant and oil, etc., and to prevent hunting with few components.
A highly reliable refrigeration system device can be obtained.

Further, since the overheat detecting means detects the superheat temperature of the refrigerant drawn into the compressor as the overheat characteristic value, it is economical and reliable with a small number of components, particularly, with improved cooling capacity and prevented hunting. High refrigeration system equipment is obtained.

Further, since the overheat detecting means detects the degree of superheat of the refrigerant at the outlet of the evaporator as an overheat characteristic value, it is economical and reliable with a small number of components, in particular, the heating capacity is improved and hunting is prevented. High refrigeration system equipment is obtained.

Further, at least one of the condenser and the evaporator is provided in parallel, and a high-pressure side throttle device or a low-pressure side throttle device corresponding to each of the provided condenser or evaporator is provided. Easy and accurate,
A highly reliable and easy-to-use refrigeration system device that prevents hunting can be obtained. Further, the control method of the refrigeration system device according to the present invention, the compressor, a condenser, a high-pressure side expansion device, a receiver tank, a low-pressure side expansion device, and a refrigeration system configured by sequentially connected by piping, A supercooling characteristic value corresponding to the degree of supercooling of the refrigerant at the condenser outlet of the refrigerator and a superheating characteristic value corresponding to the degree of superheating of the refrigerant sucked into the compressor are detected, and a target corresponding to the operating state of the refrigerator is detected. Calculating respective deviation values between the supercooling characteristic value and the target superheat characteristic value; and opening the opening from the deviation values of the supercooling characteristic and the superheat characteristic with respect to the current opening area of the high-pressure side and the low-pressure side expansion device. Correcting the amount of change in the area by adding to the opening areas of the high-pressure side and low-pressure side expansion devices, and compensating the high-pressure side and low-pressure side expansion devices arranged on both sides of the receiver tank. And controlling the opening area that is so provided with, operation efficiency is very good economical refrigeration system unit is obtained. In addition, since the step of controlling the high-pressure side and the low-pressure side expansion devices at the same time so as to be correlated with each other is provided, there is an effect that the operation state of the system can be stabilized in a short time.

[Brief description of the drawings]

FIG. 1 is a diagram showing a refrigeration system device according to first to seventh embodiments of the present invention.

FIG. 2 is a Mollier diagram showing an operation procedure of the first to eighth embodiments of the present invention.

FIG. 3 is a flowchart showing an overall operation procedure of the first to eighth embodiments of the present invention.

FIG. 4 is a flowchart showing an operation procedure of normal control according to the first embodiment of the present invention.

FIG. 5 is a flowchart showing in detail a part of normal control according to the first embodiment of the present invention.

FIG. 6 is a diagram showing another refrigeration system device according to the first to seventh embodiments of the present invention.

FIG. 7 is a diagram showing another refrigeration system device according to the first to seventh embodiments of the present invention.

FIG. 8 is a diagram showing another refrigeration system device according to the first to seventh embodiments of the present invention.

FIG. 9 is a diagram showing another refrigeration system device according to the first to seventh embodiments of the present invention.

FIG. 10 is a diagram showing another refrigeration system device according to the first to seventh embodiments of the present invention.

FIG. 11 is a diagram showing another refrigeration system device according to the first to seventh embodiments of the present invention.

FIG. 12 is a flowchart illustrating an operation procedure of normal control according to the second embodiment of the present invention.

FIG. 13 is a flowchart showing an operation procedure of normal control according to a third embodiment of the present invention.

FIG. 14 is a flowchart showing an operation procedure of normal control according to a fourth embodiment of the present invention.

FIG. 15 is a flowchart showing an operation procedure of normal control according to a fifth embodiment of the present invention.

FIG. 16 is a flowchart showing an operation procedure of normal control according to a sixth embodiment of the present invention.

FIG. 17 is a flowchart showing an operation procedure of normal control according to a seventh embodiment of the present invention.

FIG. 18 is a diagram showing a refrigeration system device according to an eighth embodiment of the present invention.

FIG. 19 is a diagram showing a conventional refrigeration system device.

[Explanation of symbols]

3 compressor, 5 four-way valve, 6a, 6b, 6c indoor heat exchanger, 11a, 11b, 11c electric expansion valve, 12 receiver tank, 13 main electric expansion valve, 14 suction pipe, 2
1, 21a-b condenser, 22, 22a-b evaporator,
23, 23a-b High-pressure side adjusting means, 24, 24a-
b Low-stage adjustment means, 25 Pressure detection means, 26, 2
6a-b Outlet temperature detecting means, 27, inlet temperature detecting means, 28 suction temperature detecting means, 29 computing unit, 30 controller, 31 refrigerant return pipe, 32 control valve, 33 heat exchange means, 34 refrigerant return pipe, 35 heat Exchange means, 36
Aperture device.

──────────────────────────────────────────────────続 き Continuation of the front page Examiner Takao Ono (56) References JP-A-7-225058 (JP, A) JP-A-60-133268 (JP, A) Jikai Sho 61-145258 (JP, U) ( 58) Field surveyed (Int. Cl. ⁷ , DB name) F25B 1/00-7/00

Claims (18)

(57) [Claims] 1. A refrigeration system in which a compressor, a condenser, a high-pressure-side expansion device, a receiver tank, a low-pressure-side expansion device, and an evaporator are sequentially connected by piping. subcooling detecting means for detecting a subcooling characteristic value corresponding to the degree of subcooling, and superheating detecting means for detecting overheating characteristic value corresponding to the degree of superheat of suction refrigerant of the compressor, the current
Based on the opening areas of the high-pressure side and low-pressure side throttle devices of
Check the detection results of the supercooling detection means and the overheating detection means.
The high-pressure side and the low-pressure side expansion device so as to approach the standard value.
And a control unit for correcting the opening area of the refrigeration system. 2. A refrigeration system in which a compressor, a condenser, a high-pressure-side expansion device, a receiver tank, a low-pressure-side expansion device, and an evaporator are sequentially connected by piping. subcooling detecting means for detecting a subcooling characteristic value corresponding to the degree of subcooling, and superheating detecting means for detecting overheating characteristic value corresponding to the degree of superheat of suction refrigerant of the compressor, the
Each detection result of the supercooling detection means and the overheating detection means and the
The target supercooling characteristic value corresponding to the operation state of the refrigeration system and
Calculating means for calculating each deviation value from the target overheat characteristic value;
The high pressure side and the low pressure
Control the aperture area of the side stop device so as to correlate with each other.
Refrigeration system comprising:
apparatus. 3. The opening of the high-pressure side and low-pressure side throttle devices.
Control means for controlling the area at the same time is provided.
The refrigeration system device according to claim 1 or claim 2. 4. The apparatus according to claim 1, wherein the control means controls the opening area of the high-pressure side or the low-pressure side throttle device a predetermined time after the operation state of the refrigerating device changes. Item 4. The refrigeration system device according to any one of Items 3 to 3 . 5. The refrigerant return pipe is provided between the receiver tank and a suction side portion of the compressor, and guides the refrigerant to the compressor while reducing the refrigerant pressure of the receiver tank. The refrigeration system control according to any one of claims 1 to 4 . 6. The refrigerant return pipe has one end on the receiver tank side connected to a portion near the upper portion of the receiver tank, and guides the refrigerant gas to the compressor while restricting the refrigerant gas near the upper portion of the receiver tank. The refrigeration system device according to claim 5, wherein 7. The refrigeration system according to claim 6 , wherein a control valve is attached to the refrigerant return pipe, and controls a pressure of the refrigerant gas based on a refrigerant temperature discharged from the compressor. 8. A heat exchange means for exchanging heat between the low-pressure refrigerant sucked into the compressor and one of a high-pressure or medium-pressure refrigerant from the condenser to a low-pressure side throttle device. The refrigeration system device according to any one of claims 1 to 4, wherein 9. A compressor is provided between any part from the condenser to the low-pressure-side throttle device and a suction-side part of the compressor, and transfers the refrigerant at any part to the suction side of the compressor. A refrigerant return pipe for guiding, a throttle device attached to the refrigerant return pipe, for controlling the pressure of the refrigerant based on the refrigerant temperature discharged from the compressor; a refrigerant controlled by the throttle device; And a heat exchange means for exchanging heat with the heat exchange means.
5. The refrigeration system device according to any one of 4 to 4 . Wherein said overheat sensing means, the refrigeration system according to claim 1, characterized in that to detect the degree of superheat of the evaporator outlet refrigerant as the heating characteristic value to claim 4. 11. A compressor, a condenser, a high-pressure side throttle device, a laser
The Shiva tank, the low-pressure side expansion device, and the evaporator are sequentially installed.
A refrigeration unit connected by a pipe and
Detects the degree of supercooling by the condensation pressure of the refrigerant in the condenser
Means for detecting supercooling, and evaporating pressure of refrigerant in the evaporator.
Overheating detecting means for detecting the degree of superheating by force;
Subcooling based on the opening area of the high-pressure side and low-pressure side expansion devices
The detection results of the rejection detection means and overheat detection means to target values
Opening of the high-pressure side and low-pressure side throttle devices so as to be close to each other.
Control means for correcting the area.
Refrigeration system equipment. 12. A compressor, a condenser, a high-pressure-side expansion device,
The Shiva tank, the low-pressure side expansion device, and the evaporator are sequentially installed.
A refrigeration unit connected by a pipe and the condenser;
Pressure of Refrigerant and Evaporation Pressure of Refrigerant in the Evaporator
Pressure of the refrigerant in the receiver tank, which is an intermediate pressure with the force
Pressure detection means for detecting the
And the intermediate pressure detecting means based on the opening area of the low-pressure side throttle device.
And the high pressure side so that the detection result of the stage approaches the target value.
And a control means for correcting the opening area of the low-pressure side throttle device.
A refrigeration system device comprising: 13. A compressor, a condenser, a high-pressure side throttling device, a laser
The Shiva tank, the low-pressure side expansion device, and the evaporator are sequentially installed.
Refrigeration equipment connected by pipes and supercooling characteristic values
Subcooling detection means for detecting the refrigerant discharge temperature of the compressor
And detecting the refrigerant suction temperature of the compressor as a superheat characteristic value.
Overheat detection means to know the current high pressure side and low pressure side
The supercool detection means and the supercool
So that each detection result of the heat detection means approaches the target value
Control to correct the opening area of the high-pressure and low-pressure throttle devices
Means, and a refrigeration system device comprising: 14. The refrigeration system apparatus according to claim 13 , wherein said overheating detecting means detects the degree of superheating of the refrigerant drawn into the compressor as the overheating characteristic value. 15. The refrigeration system according to claim 13 , wherein the overheat detecting means detects the degree of superheat of the refrigerant at the evaporator outlet as the overheat characteristic value. 16. A high-pressure throttle device or a low-pressure throttle device corresponding to each of the condenser and the evaporator provided in parallel with at least one of the condenser and the evaporator. The refrigeration system device according to any one of claims 1 to 15 , further comprising a refrigeration device. 17. A compressor, a condenser, a high-pressure throttling device, a laser
The Shiva tank, the low-pressure side expansion device, and the evaporator are sequentially installed.
In a refrigeration system configured by connecting tubes,
Subcooling characteristics corresponding to the degree of subcooling of the refrigerant at the condenser outlet of the device
Value and superheat corresponding to the degree of superheat of the refrigerant sucked into the compressor
Detecting the characteristic value and corresponding to the operation state of the refrigeration system
Each of the target supercooling characteristic value and the target superheat characteristic value
Calculating a deviation value; and
Oyo the supercooling characteristics against the opening area of the low pressure side throttle device
Of the opening area calculated from the deviation value of the heating and heating characteristics
The amount is added to the opening area of the high-pressure side and low-pressure side throttle devices.
Correction on both sides of the receiver tank.
The high-pressure side and low-pressure side throttle devices installed are
Controlling the opening area.
Control method of a refrigeration system device to perform. 18. The high-pressure side and low-pressure side expansion devices,
At the same time, there is a step of controlling to correlate with each other
The refrigeration system device according to claim 17, wherein
Control method.