JPH0827090B2 - Refrigeration system operation controller - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an operation control device for a refrigeration system in which a plurality of heat exchangers are connected in parallel to a refrigerant circuit, and particularly to cost reduction measures.

(Prior Art) Conventionally, in an air conditioner having a refrigerant circuit in which a plurality of use-side heat exchangers are arranged in parallel, the opening degree for depressurizing the refrigerant to each of the use-side heat exchangers can be adjusted. A pressure reducing valve is arranged on the upstream side of each usage-side heat exchanger to respond to the degree of superheat of each usage-side heat exchanger during refrigerant operation and to the degree of refrigerant subcooling in each usage-side heat exchanger during heating operation. It is known as a general technique to individually adjust the opening degree of each pressure reducing valve.

(Problems to be Solved by the Invention) However, when the opening degree of each pressure reducing valve is individually adjusted according to the degree of superheat of the refrigerant of each heat exchanger, as in the above-mentioned conventional one, each heat exchanger is overheated individually. Since a pressure sensor and a temperature sensor for detecting the degree are required, there is a problem that the cost cannot be sufficiently reduced.

Further, when the heat exchanger is a condenser, the refrigerant flow rate of each heat exchanger is controlled so as to be adjusted by the opening degree of the flow rate control valve. The problem arises.

The present invention has been made in view of the above points, and a main object thereof is to detect the degree of superheat or the degree of superheat detected by a single detecting means for a pressure reducing valve or a flow control valve of each heat exchanger connected in parallel. It is intended to reduce the cost by providing a means for controlling according to the cooling degree.

Further, particularly when the heat exchangers on the use side are arranged in series in a ventilation path by a common fan and are used as an evaporator or a condenser, the intake air temperature of the heat exchanger on the leeward side is lowered or risen, which is sufficient. Since the degree of superheat or the degree of subcool cannot be obtained, there is a possibility that it becomes difficult to perform constant control of the degree of superheat or the degree of subcool.

A second object of the present invention is to prevent the control failure due to the change of the intake air temperature to prevent the degree of superheat, especially when the heat exchangers are arranged in series along the air flow direction in one ventilation passage. By taking measures to perform constant supercooling degree control,
It is to improve control performance and reliability.

(Means for Solving the Problem) In order to achieve the above object, the solution means of the present invention is based on one of a plurality of heat exchangers, and the degree of superheat with respect to the valve opening degree in the heat exchanger serving as the reference. Alternatively, the constant supercooling degree control is performed, and the valve opening degree in other heat exchangers is controlled so as to have a constant relationship with the control value of the reference valve opening degree. .

Specifically, the first solution means is, as shown in FIG. 1 (not including a broken line portion, including a dotted line portion), the compressor (1).
And, to the main refrigerant pipe (9) to which the condenser (7) is connected, pressure reducing valves (4a) and (4b) with adjustable opening and evaporators (3a) and (3b) are connected in series. Multiple branch pipes (11
Refrigerant circuit (1), (11b) connected in parallel with each other
0) is assumed.

Then, as an operation control device of the refrigeration system, a single superheat degree detecting means (51) for detecting the superheat degree of the refrigerant and the output of the superheat degree detecting means (51) are received, and the plurality of evaporators (3
a), a reference opening calculation means (53A) for calculating the opening of the reference pressure reducing valve (4b) corresponding to the reference evaporator (3b) of (3b), and the reference opening control means (53A). 53A), an auxiliary opening degree calculating means (54A) for calculating the opening degree of the other pressure reducing valve (4a) so as to have a predetermined relationship with the opening degree of the reference pressure reducing valve (4b), Each opening calculation means (53A), (54
The opening control means (55A) for controlling the opening of each pressure reducing valve (4a), (4b) based on the calculation result of (A) is provided.

A second solving means is the above first solving means, wherein the evaporators (3a) and (3b) are arranged in the airflow direction so that the reference evaporator (3b) is located on the windward side in the air passage by the fan (13). Along with the superheat detection means (51) on the gas side of the branch pipe (11b) to which the reference evaporator (3b) is connected to determine the degree of superheat of the refrigerant in the reference evaporator (3b). Shall be detected. Further, the sub-opening degree calculation means (54B) is used to calculate the opening degree of the reference pressure reducing valve (4b) calculated by the reference opening degree calculation means (53A) and the superheat degree detected by the superheat degree detection means (51). The opening of the other pressure reducing valve (4a) is calculated so as to be proportional to the product.

A third solution is that, in the first solution, the evaporators (3a) and (3b) are placed in the airflow direction of the fan (13) so that the reference evaporator (3b) is on the windward side. Along with the superheat detection means (51) in the suction line of the main refrigerant pipe (9) and each evaporator (3a), (3b)
Of the reference decompression valve (4b) calculated by the reference opening calculation means (53A) and the above-mentioned superheat detection means (54A). Other pressure reducing valve (4a) so that it is proportional to the product with the degree of superheat detected in 51).
The opening degree of is calculated.

A fourth solving means is the same as the first solving means, wherein the evaporators (3a) and (3b) are arranged in separate ventilation passages, and the superheat detection means (51) is used as a reference evaporator (3b). Is installed on the gas side of the branch pipe (11b) connected to the reference evaporator (3
It is assumed that the degree of superheat of the refrigerant in b) is detected, and the auxiliary opening calculation means (54A) is used to set the opening of the reference pressure reducing valve (4b) calculated by the reference opening calculation means (53A) and another evaporator ( The opening of the other pressure reducing valve (4a) is calculated so as to be proportional to the product of the capacity ratio of the reference evaporator (3b) to 3a).

A fifth solution means is, as shown in FIG. 1 (not including a dotted line portion, including a broken line portion), a main refrigerant to which a compressor (1), a pressure reducing mechanism (6) and an evaporator (7) are connected. Plumbing (9)
The flow control valves (4a) and (4b) with adjustable opening
A refrigerating device having a refrigerant circuit (10) in which a plurality of branch pipes (11a) and (11b) connected in series with a condenser (3a) and a condenser (3b) are connected in parallel is assumed.

Then, as the operation control device of the refrigeration system, a single supercooling degree detecting means (52) for detecting the supercooling degree of the refrigerant and the output of the supercooling degree detecting means (52) are received, and the plurality of condensers are provided. Reference opening calculation means (53B) for controlling the opening of the reference flow control valve (4b) corresponding to the reference condenser (3b) which is the reference of (3a) and (3b), and the reference opening calculation Sub-opening calculation means (54B) for calculating the opening of another flow control valve (4a) so as to have a predetermined relationship with the opening of the reference flow control valve (4b) calculated by the means (53B). ) And the flow rate control valve (4) based on the calculation results of the opening degree calculation means (53B) and (54B).
The opening control means (55B) for controlling the opening of (a) and (4b) is provided.

A sixth solution is that, in the fifth solution, the condensers (3a) and (3b) are arranged in the airflow direction by the fan (13) so that the reference condenser (3b) is located on the windward side. Are arranged in series, and the supercooling degree detection means (52) is arranged in the branch pipe (11b) connected to the reference evaporator (3b) to detect the supercooling degree of the refrigerant in the reference condenser (3b). And
The sub-opening degree calculation means (54B) is used to calculate the opening degree of the reference flow control valve (4b) calculated by the reference opening degree calculation means (53B) and the supercooling degree detected by the supercooling degree detection means (52). The opening of the other flow control valve (4a) is calculated so as to be proportional to the product of

The seventh solution is that in the fifth solution, the condensers (3a) and (3b) are arranged in the airflow direction so that the reference condenser (3b) is located on the windward side in the air passage by the fan (13). Arranged in series along the supercooling degree detection means (52) in the liquid line of the main refrigerant pipe (9) to detect the average supercooling degree of each condenser (3a), (3b) The sub-opening degree calculation means (54B) is used as the opening degree of the reference flow rate control valve (4b) calculated by the reference opening degree calculation means (53A) and the supercooling degree detection means (52).
The opening degree of the other flow rate control valve (4a) is calculated so as to be proportional to the product of the degree of supercooling detected in.

An eighth solving means is the above-mentioned fifth solving means, wherein the condensers (3a) and (3b) are arranged in separate ventilation passages, and the supercooling degree detecting means (52) is used as a reference condenser (3b). Is placed on the liquid side of the branch pipe (11b) to which the reference condenser (3
It is assumed that the degree of supercooling of the refrigerant in b) is detected, and the sub-opening degree calculation means (54B) is used to determine the opening degree of the reference flow rate control valve (4b) calculated by the reference opening degree calculation means (53B). The opening of the other flow control valve (4a) is calculated so as to be proportional to the product of the capacity ratio of the reference condenser (3b) to the condenser (3a).

(Operation) With the above-described configuration, in the invention of claim (1), the reference opening calculation means (53A) determines the reference evaporator (53A) according to the superheat degree of the refrigerant detected by the superheat detection means (51). The opening for controlling the constant superheat of the reference pressure reducing valve (4b) corresponding to 3b) is calculated, and the reference calculated by the reference opening calculating means (53A) by the auxiliary opening calculating means (54A). After the opening degree of the other pressure reducing valve (4a) is calculated so as to change in a predetermined relationship according to the opening degree of the pressure reducing valve (4b), the opening degree control means (55A) controls each pressure reducing valve (4a). ) And (4b) are controlled.

Therefore, the capacity of each evaporator (3a), (3b) is adjusted to an appropriate value according to the demand by the single superheat detection means (51).

According to the invention of claim (2), in the operation of the invention of claim (1), it is detected by the superheat degree detecting means (51) arranged in the branch pipe (11b) to which the reference evaporator (3b) is connected. The reference opening calculating means (53A) calculates the opening of the reference pressure reducing valve (4b) according to the degree of superheat of the refrigerant, and the auxiliary opening calculating means (54A) calculates the reference as above. The opening of the other pressure reducing valve (4a) is calculated so as to be proportional to the product of the opening of the pressure reducing valve (4b) and the degree of superheat of the refrigerant.

Therefore, while the superheat constant control is performed on the opening of the reference pressure reducing valve (4b), the reference pressure reducing valve (4a) can be controlled without causing the control failure due to the decrease of the intake air temperature. Based on the opening control value in 4b), constant superheat constant control is performed quickly and the control performance is improved.

According to the invention of claim (3), in the operation of the invention of claim (1), both branch pipes (11a), () are provided by the superheat detection means (51) arranged in the suction line of the refrigerant circuit (10). 1
The average degree of superheat of the refrigerant drawn from 1b) is detected. Then, with the superheat degree of the refrigerant in the suction line as a parameter, constant superheat degree control similar to that of the invention of claim (2) is performed. Therefore, the risk of liquid backing of the liquid refrigerant to the compressor (1) is prevented and reliability is improved.

According to the invention of claim (4), in the operation of the invention of claim (1), when each evaporator (3a), (3b) is arranged in a separate ventilation passage, a sub-opening degree calculation means (54A) By this, the opening of another pressure reducing valve (4a) is calculated so as to be proportional to the product of the capacity ratio of each evaporator (3a), (3b) and the opening of the reference pressure reducing valve (4b). The superheat constant control is performed so that the superheats in the reactors (3a) and (3b) are maintained at almost the same value.

In the invention of claim (5), reference opening calculation means (53B)
The opening degree for performing constant supercooling degree control for the reference flow control valve (4b) corresponding to the reference condenser (3b) based on the supercooling degree of the refrigerant detected by the supercooling degree detection means (52). Is calculated and the opening degree of the other flow rate control valve (4a) is calculated by the auxiliary opening degree calculation means (54B) so as to have a predetermined relationship with the opening degree, and then by the opening degree control means (55B). The opening degree of each flow control valve (4a), (4b) is controlled.

Therefore, by the single supercooling degree detection means (52),
The capacities of a plurality of condensers (3a), (3b) connected in parallel will be appropriately adjusted according to requirements.

According to the invention of claim (6), in the invention of claim (5), the supercooling degree detecting means (52) is used to determine the degree of supercooling of the refrigerant in the reference condenser (3b) arranged on the windward side. The opening of the reference flow control valve (4b) is calculated, and the reference opening control valve (4b) is calculated by the auxiliary opening calculation means (54B).
To be proportional to the product of the opening of b) and the degree of supercooling of the refrigerant,
The opening of the other flow control valve (4a) is calculated.

Therefore, first, after performing the constant supercooling degree control of the reference condenser (3b), the other flow control valves (4a) are also
The constant supercooling degree constant control is performed based on the control value of the reference flow rate control valve (4b) without causing control failure due to the rise of the intake air temperature, and the control performance is improved.

According to the invention of claim (7), in the operation of the invention of claim (5), the same as the invention of claim (6) based on the signal of the supercooling degree detection means (52) arranged in the liquid line. Since the constant supercooling degree control is performed, the flash of the refrigerant in the liquid line is prevented, and the reliability is improved.

In the invention of claim (8), a plurality of condensers (3a), (3
When b) is placed in a separate ventilation passage, other flow rate control is performed so as to be proportional to the product of the opening control value of the reference flow control valve (4b) and the capacity ratio of each condenser (3a), (3b). Since the opening degree of the valve (4a) is controlled, the constant supercooling degree control is performed in which the supercooling degree in each of the condensers (3a) and (3b) is maintained at a substantially constant constant value.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings starting from FIG.

First, the first embodiment according to the inventions of claims (1) to (3) and (5) to (7) will be described with reference to FIGS. 2 to 4, and FIG. The whole structure of such an air conditioner is shown, and is a so-called multi-type in which three indoor units (A) to (C) are connected in parallel to one outdoor unit (X).

In the outdoor unit (X), (1) is a compressor whose operating frequency, that is, operating capacity is variably adjusted by an inverter (12), (2) is a solid line in the figure during cooling operation, and a broken line in the figure during heating operation. The four-way switching valves that switch as in (3a) and (3b) are the first and second outdoor heat exchangers as heat source side heat exchangers that function as a condenser during cooling operation and as an evaporator during heating operation. , (4a), (4b) each function as a flow rate control valve that controls the flow rate of the refrigerant during the cooling operation, and an outdoor electric expansion valve that functions as a pressure reducing valve that reduces the pressure during the heating operation, and (5) is a liquid refrigerant Is a receiver for storing, and (8) is an accumulator for removing the liquid refrigerant in the suction refrigerant.

The indoor units (A) to (C) have the same configuration, and (6) is an indoor electric expansion valve as a pressure reducing mechanism that decompresses the refrigerant during cooling operation and adjusts the refrigerant flow rate during heating operation, and (7) It is an indoor heat exchanger that functions as an evaporator during cooling operation and as a condenser during heating operation.

In the outdoor unit (X), the compressor (1), the four-way switching valve (2), the accumulator (8) and the receiver (5) are connected in series by the main refrigerant pipe (9), while The first outdoor heat exchanger (3a) and the first outdoor electric expansion valve (4a) are connected in series by the first branch pipe (11a), and the second outdoor heat exchanger (3a) and the second outdoor electric expansion valve ( 4a) is connected by a second branch pipe (11b) so that the refrigerant can flow, and the first and second branch pipes (11a) and (11b) are connected in parallel to the main refrigerant pipe (9), respectively. There is. The outdoor heat exchangers (3a) and (3b) are connected to the outdoor fan (1
In the ventilation passage according to 3), the first outdoor heat exchanger (3a) is located on the leeward side, and the second outdoor heat exchanger (3b) is located on the leeward side in series along the air flow direction. The upper second outdoor heat exchanger (3b) serves as a reference evaporator or a reference condenser. That is, by using the two outdoor heat exchangers (3a) and (3b) together as described above, a wide capacity adjustment range on the outdoor side is ensured.

Further, each device of each indoor unit (A) to (C) is connected in parallel to the main refrigerant pipe (9) by an indoor branch pipe, and each of the above devices (1) to (8) is mainly connected. By connecting the refrigerant pipe and the branch pipe to the closed circuit, a main refrigerant circuit (11) having a heat pump function of releasing the heat obtained by heat exchange with each indoor air to the outdoor air is configured.

In addition, the device has many sensors
(Tho) is arranged in the outdoor unit (X), and an outdoor air temperature sensor for detecting the outdoor air temperature, (Th1) is the second
A gas pipe sensor arranged on the gas pipe side of the branch pipe (11b) for detecting the gas refrigerant temperature T ₁ in the second outdoor heat exchanger (3b), and (Th2) is the second outdoor heat exchanger (3b). Is installed on the liquid pipe side of the liquid pipe sensor for detecting the liquid refrigerant temperature T ₂ , (Th
3) is a room temperature sensor for detecting the intake air temperature corresponding to room temperature, and (Hp) is arranged in the discharge pipe, which is arranged at the air inlet of each indoor unit (A) to (C), and is saturated by the condensation pressure. A high-pressure sensor that detects a high pressure Tc corresponding to the temperature (hereinafter, simply referred to as "condensation temperature"), (Lp) is disposed in the suction pipe, and corresponds to the vapor pressure equivalent saturation temperature (hereinafter, simply referred to as "evaporation temperature"). It is a low-voltage sensor that detects low-voltage Te.
During the heating operation of the device, the temperature difference between the intake superheated refrigerant temperature T ₁ detected by the gas pipe sensor (Th1) and the evaporation temperature Te detected by the low pressure sensor (Lp) (T ₁ −T _e ) 2 The superheat degree Sh2 of the refrigerant in the outdoor heat exchanger (reference heat source side heat exchanger) (3b) is calculated, and the superheat degree is calculated by the low pressure sensor (Lp) and the gas pipe sensor (Th1). A detection means (51) is configured. Further, in the cooling operation, the temperature deviation (T _c -T ₂₎ between the liquid refrigerant temperature T ₂ detected by the condensation temperature Tc and the liquid pipe sensor which is detected by the pressure sensor (Hp) (Th2), second The subcooling degree Sc2 of the refrigerant in the outdoor heat exchanger (3b) is detected,
The high-pressure sensor (Hp) and the liquid pipe sensor (Th2) constitute a supercooling degree detecting means (52).

Although not shown, each sensor is connected to a controller that controls the operation of the device so that a signal can be input, and the controller operates the operating capacity of the compressor (1) according to the output signal of each sensor. Outdoor electric expansion valve (4
The operation of each device is controlled such as the opening degree of a) and (4b), the air flow rate of the outdoor fan (13), the opening degree of each indoor electric expansion valve (6) ,.

Next, each outdoor electric expansion valve (4
a), (for the control of the opening degree of 4b) to be described with reference to the flow chart of FIG. 3 and FIG. 4, the cooling operation, in step S _1, the second outdoor detected by the superheat degree detecting means (51) Enter the superheat degree Sh2 of the refrigerant in the heat exchanger (3b),
In step S _2, the degree of superheat Sh2 determines the opening Ev2 of the second outdoor electric expansion valve to a predetermined target value Sh2s (4b). That is, the opening change amount ΔEv2 based on the following formula ΔEv2 = K ₀ · (Sh2s−Sh2) (where K ₀ is a predetermined constant)
After calculating, the new opening based on the following equation Ev2 = Ev2o + ΔEv2 (where Ev2o is the opening control value of the second outdoor electric expansion valve (4b) in fully open sampling)
Determine Ev2.

Then, in step S _3, the opening degree of the formula _{Ev1 = K 1 · (T 1} -T e) · Ev2 (1) ( provided that, K ₁ is a predetermined constant) the first outdoor electric expansion valve on the basis of (4a) After calculating and determining Ev1, step S ₄
Then, the signals of the opening degrees Ev1 and Ev2 are output to drive the outdoor electric expansion valves (4a) and (4b).

On the other hand, during heating operation, in step S ₁₁ , the second outdoor heat exchanger (3b) detected by the supercooling degree detection means (52).
Enter the supercooling degree Sc2 of the refrigerant in, in step S _12,
The same procedure as the steps S _2, the degree of supercooling Sc2
Accordingly, the opening Ev2 of the second outdoor electric expansion valve (4b) is determined. Then, in step S _13, the opening degree of the formula _{Ev1 = K 2 · (T c} -T 2) · Ev2 (2) ( however, K ₂ are predetermined constants) first outdoor electric expansion valve on the basis of (4a) After calculating and determining Ev1, step S ₁₄
Then, the opening signals Ev1 and Ev2 determined above are output to drive the outdoor electric expansion valves (4a) and (4b).

In the above flow, the invention of claim (1) to (3), the step S _2, receives the output of the superheating degree detecting means (51), the plurality of outdoor heat exchanger (evaporator) (3a),
Reference opening calculation for calculating the opening of the second outdoor electric expansion valve (reference pressure reducing valve) (4b) corresponding to the second outdoor heat exchanger (reference evaporator) (3b) that is the reference of (3b) Means (53A)
There is constituted by step S _3, the first outdoor electric expansion so as to have a predetermined relationship to the opening of the reference opening control means computed the second outdoor electric expansion valve at (53A) (4b) An auxiliary opening degree calculating means (54A) for calculating the opening degree of the valve (other pressure reducing valve) (4a) is configured. Further, in step S _4, each opening calculating means (53A), the outdoor electric expansion valve on the basis of the calculation result of (54A) (4a), opening control means for controlling the opening of (4b) (55A) Is configured.

In the inventions of claims (5) to (7), the step S
₁₂ , the output of the supercooling degree detection means (52) is received,
A second outdoor heat exchanger (reference condenser) (3b) which is a reference among the plurality of outdoor heat exchangers (condensers) (3a) and (3b)
Second outdoor electric expansion valve (reference flow control valve) (4
reference opening calculating means for controlling the opening of b) (53B) is constructed, the opening degree of the step S _13, the second outdoor electric expansion valve which is calculated by the reference opening calculating means (53B) (4b) To the second outdoor electric expansion valve (other flow control valve) (4a) so as to have a predetermined relationship with
B) is configured. Further, in step S _14, the respective opening calculating means (53B), the outdoor electric expansion valve on the basis of the calculation result of (54B) (4a), opening control means for controlling the opening of (4b) (55B) Is configured.

Therefore, according to the invention of claim (1), during the heating operation of the device, the plurality of outdoor units are operated according to the superheat degree Sh of the refrigerant detected by the superheat degree detection means (51) by the reference opening degree calculation means (53A). Opening degree of the second outdoor electric expansion valve (reference pressure reducing valve) (3b) corresponding to the first outdoor heat exchanger (reference evaporator) (3b) that is the reference of the heat exchangers (3a) and (3b) Ev2 is calculated,
The opening E of the second outdoor electric expansion valve (4b) calculated by the reference opening calculation means (53A) by the auxiliary opening calculation means (54A)
After the opening Ev1 of the first outdoor electric expansion valve (another pressure reducing valve) (4a) is calculated so as to change in a predetermined relationship according to v2, each outdoor electric valve is controlled by the opening control means (55A). Expansion valve (4
The openings Ev1 and Ev2 in a) and (4b) are controlled.

In that case, only a single superheat detection means (51) consisting of a low pressure sensor (Lp) and one gas pipe sensor (Th1) is required, and as in the conventional one, a plurality of outdoor heat exchangers (3a),
It is not necessary to provide a gas pipe sensor for each (3b). Therefore, the capacity of the plurality of outdoor heat exchangers (3a), (3b) can be adjusted to an appropriate value according to the demand by the single superheat detection means (51), thereby reducing the cost. It can be achieved.

According to the invention of claim (2), in the invention of claim (1), the gas pipe sensor (Th1), which is one of the sensors constituting the superheat detection means (51), is the second outdoor heat exchanger (reference evaporator). (3b) is connected to the second branch pipe (11b) connected to the second branch pipe (11b), and the superheat detection means (51) detects the superheat degree Sh2 of the refrigerant in the second outdoor heat exchanger (3b). Then, by the reference opening calculation means (53A), the degree of superheat Sh2
According to the above, the opening degree Ev2 of the second outdoor electric expansion valve (4b) is calculated, and further, the opening degree of the second outdoor electric expansion valve (4b) calculated by the sub-opening calculation means (54A). The first value is proportional to the product of Ev2 and the refrigerant superheat degree Sh2 (= T ₁ −T _e ).
The opening degree Ev1 of the outdoor electric expansion valve (4a) is calculated.

That is, as in the above embodiment, each outdoor heat exchanger (3
The a) and (3b) are the second in the ventilation path by the outdoor fan (13).
When the outdoor heat exchanger (3b) is installed in series along the airflow direction so as to be on the windward side, the outdoor heat exchanger (3a) on the leeward side is connected to the second outdoor heat exchanger (3b). Since the cold air cooled by heat exchange is sucked in, the first branch pipe (11a)
The superheat degree Sh1 of the refrigerant in is lower than the superheat degree Ev2 in the second branch pipe (11b). Therefore, the degree of superheat Sh1 is not sufficient, and the opening degree of the first outdoor electric expansion valve (4a)
With respect to Ev1, there is a possibility that the constant degree of superheat cannot be controlled.

On the other hand, in the present invention, the second outdoor electric expansion valve (4
When the opening degree Ev2 of b) is determined, the opening degree Ev1 of the first outdoor electric expansion valve (4a) is automatically calculated from the opening degree Ev2 based on the above equation (1). In reality, each outdoor heat exchanger (3
The heat exchange amounts in a) and (3b) are not necessarily proportional to the opening degrees Ev1 and Ev2, but can be approximately calculated by the above equation (1). Therefore, first, the second outdoor electric expansion valve (4b) is subjected to constant superheat control on the side of the second outdoor heat exchanger (3b) serving as a reference, and is approximately set to be proportional to the opening degree Ev2. Based on the calculation formula, constant superheat degree control of the first outdoor electric expansion valve (4a) can be performed simply and quickly without causing control failure due to a decrease in intake air temperature, thus improving control performance. It can be achieved.

In the invention of claim (3), although not shown, the gas pipe sensor (Th1) in the above embodiment is installed in the suction line (9b) of the refrigerant circuit (10), and the branch pipes (11a), (1)
The average superheat degree Sho of the refrigerant drawn from 1b) is detected. Therefore, the average degree of superheat of the refrigerant in the suction line (9b) is the same as that of the invention of claim (2).
Each outdoor electric expansion valve (4a), (4
Since the constant superheat degree control for the opening degrees Ev1 and Ev2 in b) is performed, and the decrease in the intake superheat degree is prevented, the risk of liquid compression due to liquid back to the compressor (1) is effective. To be prevented. Therefore, in addition to the effect of the invention of claim (2), the reliability can be improved.

According to the invention of claim (5), during the cooling operation in the above-described embodiment, the second opening is calculated by the reference opening degree calculation means (53B) according to the supercooling degree Sc of the refrigerant detected by the supercooling degree detecting means (52).
The opening degree Ev2 of the outdoor electric expansion valve (4b) is calculated, and the opening degree of the first outdoor electric expansion valve (4a) is calculated by the auxiliary opening degree calculation means (54B) so as to have a predetermined relationship with the opening degree Ev2. After Ev1 is calculated, the opening control means (55B) controls the openings Ev1 and Ev2 of the outdoor electric expansion valves (4a) and (4b).

Therefore, it is possible to adjust the capacities of the plurality of outdoor heat exchangers (3a) and (3b) connected in parallel by the single supercooling degree detection means (52) to an appropriate value as required, Therefore, the cost can be reduced.

According to the invention of claim (6), in the invention of claim (5), the subcooling degree detecting means (52) detects the subcooling degree Sc2 of the refrigerant on the second outdoor heat exchanger (3b) side,
The opening degree Ev2 of the second outdoor heat exchanger (3b) is calculated by the reference opening degree calculation means (53B) according to the degree of supercooling Sc2, and as shown in the above equation (2), the auxiliary opening degree is calculated. The calculation means (54B) adjusts the opening degree Ev1 of the first outdoor electric expansion valve (4a) so as to be proportional to the product of the opening degree Ev2 of the second outdoor electric expansion valve (4b) and the refrigerant subcooling degree Sc2. Is calculated.

Here, as in the conventional case, each outdoor electric expansion valve (4a),
With regard to the openings Ev1 and Ev2 of (4b), the degree of supercooling is detected and the constant degree of supercooling is individually controlled, so that the intake air temperature of the first outdoor heat exchanger (3a) on the leeward side is the second Since the temperature rises due to the heat exchange in the outdoor heat exchanger (3b), the degree of supercooling may not be sufficient and there is a possibility that the constant degree of supercooling cannot be controlled.

On the other hand, in the present invention, based on the above equation (2),
The opening degree Ev1 of the first outdoor electric expansion valve (4a) is automatically obtained from the opening degree control value Ev2 of the second outdoor electric expansion valve (4b).
Therefore, first, while performing the constant supercooling degree control of the second outdoor heat exchanger (3b) on the reference side, the control failure caused by the rise of the intake air temperature may be caused based on the opening control value Ev2. Instead, the degree of opening Ev1 of the first outdoor / outdoor outdoor electric expansion valve (4a) can be simply and quickly controlled at a constant supercooling degree, and thus the control performance can be improved.

According to the invention of claim (7), in the same operation as that of the invention of claim (6), the liquid pipe sensor (Th2) forming a part of the supercooling degree detecting means (52) is the refrigerant circuit (10). Since it is arranged in the liquid line (9a), the average degree of supercooling Sco in the liquid line (9a) is used as a parameter to supercool the opening Ev1, Ev2 of each outdoor electric expansion valve (4a), (4b). Constant control is performed. Therefore, as compared with the case where the second branch pipe (11b) is arranged as in the above embodiment, in the liquid line (9a), for example, the outdoor electric expansion valves (4a), (4).
It is possible to effectively prevent the refrigerant from flashing or the like due to the increase in the refrigerant temperature due to the pressure reducing effect in b), thus improving the reliability.

Next, a second embodiment according to the inventions of claims (4) and (8) will be described with reference to FIG.

FIG. 5 shows the configuration of the air conditioner according to the second embodiment, which includes two branch pipes (11a) and (11b) for the refrigerant circuit (1
Outdoor heat exchangers (3a), (3
b) is installed in the ventilation passage by separate outdoor fans (13a) and (13b). Other configurations are the same as those of the first
Same as the embodiment.

The control content in this embodiment is the same as the flow in FIGS. 3 and 4 in the first embodiment. However, in the present embodiment, step S ₃ or S ₁₃
In the above, by the sub-opening degree calculation means (54A or 54B), the following equation Ev1 = K ₃ · (1 / m) · Ev2 (3) (where K ₃ is a positive constant and m is the first outdoor heat exchanger ( 3a)
And the capacity ratio of the second outdoor heat exchanger (3b)),
The opening Ev1 of the first outdoor heat exchanger (3a) is calculated.

Therefore, according to the invention of claim (4), during the cooling operation of the apparatus, by the same operation as the invention of claim (1), the reference opening calculation means (53A) and the sub opening calculation means (54A) Opening Ev1 and Ev2 of each outdoor electric expansion valve (4a), (4b)
Is calculated, and each opening Ev1 and Ev2 is controlled by the opening control means (55A). Here, each outdoor heat exchanger (3a),
The superheats Sh1 and Sh2 in (3b) depend on the outdoor heat exchanger (3
Each outdoor electric expansion valve (4a) for the capacity of a), (3b),
Since it is determined by the relative values of the openings Ev1 and Ev2 in (4b),
Each outdoor electric expansion valve (4a), (4b) as in the above formula (3)
The outdoor heat exchangers (3a) and (3b) are calculated by calculating the opening degrees Ev1 and Ev2 of each and controlling the opening degrees according to the values and the capacity ratio.
The superheats Sh1 and Sh2 of the refrigerant are maintained at substantially the same value.

Therefore, the outdoor heat exchanger (3a), which is a plurality of evaporators,
Even when (3b) is installed in a separate ventilation passage, the single superheat detection means (51) does not impair control performance and reliability, and each outdoor heat exchanger (3a), (3b) ), The constant superheat degree of the refrigerant can be controlled.

In the invention of claim (8), the plurality of outdoor heat exchangers (3a) and (3b), which are condensers, are arranged in separate ventilation passages so as to be easily derived from the action of the invention of claim (4). During the cooling operation of the installed device, the single supercooling degree detection means (52) prevents the supercooling degree of the refrigerant in each of the outdoor heat exchangers (3a) and (3b) without impairing the control performance and reliability. It is possible to effectively ensure constant control.

Here, in the invention of the above-mentioned claim (4) or claim (8), the superheat degree detecting means (51) or the supercooling degree detecting means (52).
May be installed in the suction line (9b) or the liquid line (9a).

In addition, in each of the above-described embodiments, an example in which two outdoor heat exchangers (3a) and (3b) are arranged has been described, but the present invention is not limited to the embodiments according to the present invention, and three or more are provided. It can also be applied to the one in which the outdoor heat exchanger is arranged, and at that time as well, by using the outdoor heat exchanger arranged on the windward side as the reference evaporator or the reference condenser, the same as in the above embodiment. Can be controlled.

Further, in the above-mentioned embodiment, the valve opening control example of the outdoor heat exchanger has been described.However, even when a plurality of outdoor heat exchangers are arranged, the present invention is applied, and a single superheat degree detecting means or a superheat degree detecting means is provided. It is possible to control the openings of the pressure reducing valve and the flow control valve of each indoor heat exchanger according to the signal from the cooling degree detecting means.

Further, in the above embodiment, a plurality of indoor units (A)
Although the case where (C) to (C) are arranged has been described, it goes without saying that the invention can be applied to a case where one indoor unit is connected.

(Effect of the invention) As described above, according to the invention of claim (1),
In a refrigeration system in which a plurality of evaporators are connected in parallel in a refrigerant circuit, constant superheat control is performed on the opening degree of the pressure reducing valve of the reference evaporator according to a signal from a single superheat detection means, and the opening Since the pressure reducing valve opening of other evaporators is controlled so that it has a constant opening with respect to the temperature control value, the capacity of multiple evaporators can be adjusted appropriately with a single superheat detection means. It can be adjusted to any value, and thus cost can be reduced.

According to the invention of claim (2), in the invention of claim (1), when the plurality of evaporators are arranged in series along the airflow direction so that the reference evaporator is on the windward side, the reference evaporator is The superheat constant control is performed on the opening of the reference pressure reducing valve according to the degree of superheat in the connected branch pipe, and the other pressure reducing valve is opened so as to be proportional to the product of the control value of the reference pressure reducing valve opening and the degree of superheat. Since the degree of temperature control is controlled, it is possible to eliminate the influence of the decrease in the intake air temperature on other opening of the pressure reducing valve, and to perform the constant superheat degree constant control easily and quickly. Can be improved.

According to the invention of claim (3), in the invention of claim (1), when a plurality of evaporators are arranged in series along the airflow direction so that the reference evaporator is on the windward side in the ventilation passage by the fan,
Since the degree of superheat in the suction line after merging is used as a parameter and the degree of opening of each pressure reducing valve is controlled to be the same degree of superheat as in the invention of claim (2), liquid backing to the compressor is effectively performed. Therefore, the reliability can be improved in addition to the effect of the invention of claim (2).

According to the invention of claim (4), in the invention of claim (1), when a plurality of evaporators are arranged in individual ventilation passages, the opening degree of the pressure reducing valve of the reference evaporator and the capacity of each evaporator Since the opening degree of the other pressure reducing valve is controlled so as to be proportional to the product of the ratio, the superheat degree in each evaporator can be maintained at almost the same value. Therefore, the above claims (2) and ( The effect of the invention of 3) can be obtained together.

According to the invention of claim (5), in the refrigeration system in which a plurality of condensers are connected in parallel in the refrigerant circuit, the flow rate control of the reference condenser is performed in response to a signal from a single supercooling degree detection means. A constant degree of supercooling is controlled for the opening of the valve, and other flow rate control valve openings are controlled so as to have a constant degree of opening control value. The detection means can adjust the capacities of the plurality of condensers to appropriate values according to demands, and thus the cost can be reduced.

According to the invention of claim (6), in the invention of claim (5), when a plurality of condensers are arranged in series along the air flow direction so that the reference condenser is on the windward side, Performs constant supercooling degree control for the opening of the reference flow control valve corresponding to the reference condenser according to the supercooling degree in the connected branch pipe, and determines the product of the opening of the reference flow control valve and the supercooling degree. Since the other flow control valve openings are controlled so as to be proportional to each other, the influence of the rise in intake air temperature on the other flow control valve openings is eliminated, and simple and quick constant supercooling degree control is performed. Therefore, the control performance can be improved.

According to the invention of claim (7), in the invention of claim (5), when a plurality of condensers are arranged in series along the airflow direction so that the reference condenser is on the windward side in the ventilation passage by the fan, The opening degree of each flow rate control valve, wherein the degree of supercooling in the subsequent suction line is used as a parameter.
Since the same degree of supercooling control is performed as in the invention of claim 1, it is possible to effectively prevent flushing in the liquid line. Therefore, in addition to the effect of the invention of claim (6), the reliability is improved. Can be achieved.

According to the invention of claim (8), in the invention of claim (5), when a plurality of condensers are arranged in individual ventilation passages, the opening degree of the flow control valve of the reference condenser and other condensers Since the openings of the other flow control valves are controlled so as to be proportional to the product of the capacity ratio, the constant supercooling degree control that maintains the supercooling degree in each condenser at approximately the same value should be performed. Therefore, the effects of the inventions of the above claims (6) and (7) can be obtained together.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention. 2 to 4 show the first embodiment, FIG. 2 is a refrigerant piping system diagram of the air conditioner, FIG. 3 is a flow chart showing the control contents during heating operation, and FIG. 4 is during cooling operation. FIG. 5 is a flow chart showing the control contents in FIG. 5, and FIG. 5 is a refrigerant piping system diagram of the air conditioner according to the second embodiment. 1 ... Compressor 3a ... 1st outdoor heat exchanger (other evaporator or condenser) 3b ... 2nd outdoor heat exchanger (reference evaporator or condenser) 4a ... 1st outdoor electric expansion valve ( Other pressure reducing valves or flow control valves) 4b: Second outdoor electric expansion valve (reference pressure reducing valve or flow control valve) 6 ... Indoor electric expansion valve (pressure reducing mechanism) 7 ... Indoor heat exchanger (condenser or evaporation) 9) Main refrigerant pipe 10 ... Refrigerant circuit 11a ... 1st branch pipe 11b ... 2nd branch pipe 13 ... Outdoor fan 51 ... Superheat detection means 52 ... Supercooling degree detection means 53 ... Reference opening calculation means 54 ... Sub opening calculation means 55 ... Opening control means

Claims (8)

[Claims] 1. A main refrigerant pipe (9) to which a compressor (1) and a condenser (7) are connected, a pressure reducing valve (4a), (4b) having an adjustable opening and an evaporator (3a). ), (3b) connected in series with a plurality of branch pipes (11a), (11b) connected in parallel to each other in a refrigerating apparatus having a refrigerant circuit (10) for detecting the degree of superheat of the refrigerant. One superheat detection means (51)
And receiving the output of the superheat detection means (51) to open the reference pressure reducing valve (4b) corresponding to the reference evaporator (3b) serving as the reference among the plurality of evaporators (3a), (3b). Reference opening calculation means (53A) for calculating the degree, and the reference opening control means (53A)
The auxiliary opening degree calculation means (54A) for calculating the opening degree of the other pressure reducing valve (4a) so as to have a predetermined relationship with the opening degree of the reference pressure reducing valve (4b) calculated in Degree calculation means (53
A), (54A) based on the calculation results of each pressure reducing valve (4a), (4a)
An operation control device for a refrigeration system, comprising: an opening control means (55A) for controlling the opening of b). 2. The evaporator (3a), (3b) is arranged in series along the air flow direction so that the reference evaporator (3b) is located on the windward side in the ventilation passage of the fan (13), and the overheat is generated. The degree detecting means (51) includes a branch pipe (11) to which the reference evaporator (3b) is connected.
It is arranged on the gas side of b) and detects the degree of superheat of the refrigerant in the reference evaporator (3b).
B) is another value proportional to the product of the opening degree of the reference pressure reducing valve (4b) calculated by the reference opening degree calculation means (53A) and the superheat degree detected by the superheat degree detection means (51). The method for calculating the opening of a pressure reducing valve (4a), characterized in that (1)
An operation control device for the refrigeration system described. 3. The evaporator (3a), (3b) is arranged in series along the air flow direction so that the reference evaporator (3b) is located on the windward side in the ventilation passage of the fan (13), and the overheat is generated. The degree detection means (51) is arranged in the suction line of the main refrigerant pipe (9) to detect the average degree of superheat of each evaporator (3a), (3b), and the auxiliary opening degree calculation means (54A). ) Is another decompression so as to be proportional to the product of the opening of the reference pressure reducing valve (4b) calculated by the reference opening calculation means (53A) and the superheat detected by the superheat detection means (51). The operation control device for a refrigeration system according to claim 1, wherein the operation control device calculates the opening of the valve (4a). 4. The evaporators (3a), (3b) are arranged in separate air passages, and the superheat detection means (51) is a branch pipe (11b) to which the reference evaporator (3b) is connected. Is arranged on the gas side of the unit to detect the degree of superheat of the refrigerant in the reference evaporator (3b), and the auxiliary opening calculation means (54A) is the reference pressure reducing valve calculated by the reference opening calculation means (53A). To calculate the opening of the other pressure reducing valve (4a) so as to be proportional to the product of the opening of (4b) and the capacity ratio of the reference evaporator (3b) to the other evaporator (3a). The operation control device for a refrigerating apparatus according to claim (1). 5. A flow control valve (4a), whose opening can be adjusted with respect to a main refrigerant pipe (9) to which a compressor (1), a pressure reducing mechanism (6) and an evaporator (7) are connected. 4b) and condenser (3a),
(3b) and multiple branch pipes (11a), (1
In a refrigeration system having a refrigerant circuit (10) in which 1b) are connected in parallel, a single supercooling degree detecting means (5
2) and the output of the supercooling degree detection means (52), and a reference flow rate control valve (a) corresponding to the reference condenser (3b) serving as a reference among the plurality of condensers (3a) and (3b). 4b) has a predetermined relationship with the reference opening control means (53B) for controlling the opening and the opening of the reference flow control valve (4b) calculated by the reference opening calculation means (53B). The sub-opening degree calculation means (54B) for calculating the opening degree of the other flow rate control valve (4a) and each flow rate control valve (4a) based on the calculation results of the respective opening degree calculation means (53B), (54B). ), (4b) opening degree control means (55B) for controlling the opening degree, and an operation control device for a refrigerating apparatus. 6. Condensers (3a), (3b) are arranged in series along the air flow direction so that the reference condenser (3b) is on the windward side in the ventilation passage of the fan (13). The cooling degree detecting means (52) includes a branch pipe (11) to which the reference evaporator (3b) is connected.
It is arranged in b) to detect the degree of supercooling of the refrigerant in the reference condenser (3b), and an auxiliary opening degree calculation means (54B)
Is proportional to the product of the opening degree of the reference flow rate control valve (4b) calculated by the reference opening degree calculation means (53B) and the degree of supercooling detected by the degree of supercooling detection means (52). 6. The operation control device for a refrigerating apparatus according to claim 5, wherein the opening degree of the flow control valve (4a) is calculated. 7. The condensers (3a), (3b) are arranged in series along the air flow direction so that the reference condenser (3b) is on the windward side in the ventilation passage of the fan (13). The cooling degree detecting means (52) is arranged in the liquid line of the main refrigerant pipe (9) to detect the average degree of supercooling of each condenser (3a), (3b), and the auxiliary opening degree calculating means. (54B) is proportional to the product of the opening degree of the reference flow rate control valve (4b) calculated by the reference opening degree calculating means (53A) and the supercooling degree detected by the supercooling degree detecting means (52). The operation control device for a refrigerating apparatus according to claim 5, wherein the opening degree of the other flow control valve (4a) is calculated as described above. 8. The condensers (3a), (3b) are arranged in separate air passages, and the supercooling degree detecting means (52) is a branch pipe (11b) to which the reference condenser (3b) is connected. ) Is arranged on the liquid side to detect the degree of supercooling of the refrigerant in the reference condenser (3b), and the auxiliary opening degree calculation means (54B) is calculated by the reference opening degree calculation means (53B). Reference flow control valve (4
b) opening and reference condenser (3
Other flow control valves (4
The operation control device for a refrigerating apparatus according to claim 5, wherein the opening degree of a) is calculated.