JPH09152169A - Multi-type air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a sensing of an operating current at an outdoor device by a method wherein in a freezing cycle having a plurality of indoor devices connected to the outdoor device, an operating current of a compressor is held in response to an operating frequency of the compressor during a heating operation and an electrical energization for an electrical heater is controlled. SOLUTION: In a separate type air conditioner having an electrical heater 16 connected to an outdoor device X, a four-way changing-over valve 2 is changed over during a heating operation to energize a compressor 1, and the refrigerant is circulated in a refrigerant circulating circuit 19. Then, an indoor heat exchanger 15 is acted as a condenser and in turn an outdoor heat exchanger 15 is acted as an evaporator. Heat absorbed by the outdoor heat exchanger 3 is discharged out of the indoor heat exchanger 15. An electrical energization control for the electrical heater 16 is performed such that if there is a request for an electrical energization, an operating frequency and a condensing temperature are held, a high pressure is held in response to this condensing temperature, an input current of the compressor 1 is attained and when an allowable current for the electrical heater is higher than the input current, the electrical energization for the electrical heater 16 is allowed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-type air conditioner having an electric heater in an indoor unit.

[0002]

2. Description of the Related Art Conventionally, an electric heater is provided in an indoor unit (indoor unit) of a multi-type air conditioner, and the heating capacity is supplemented by the electric heater to improve quick heating at the start of operation. (For example, JP-A-62-16283
No. 7). FIG. 5 is a power supply side circuit diagram in the outdoor unit (outdoor unit) of the conventional multi-type air conditioner. In the figure, 45d is a power supply terminal, to which a single-phase 200V AC power supply of 50 Hz or 60 Hz is connected. The power supply terminal 45d has a fuse 46, A
A power transistor (not shown) for driving the compressor is connected via the C noise filter 43, the power relay 44, and the like, and in parallel with this, terminal boards 45a, 45b,
45c, ... are connected to each of these terminal boards 45a, 4
5b, 45c, ... through the indoor units A, B, C,
・ ・ Power is supplied to. In the figure, 41 is
It is a first current transformer for detecting the total operating current It supplied to the air conditioner, and 42 in the figure is a second current transformer for detecting the input current of the compressor.

FIG. 6 is a flow chart showing the operation of the air conditioner when a request to energize an electric heater is made in the indoor units A, B, C, ... First, when a request is made to energize the electric heater from the indoor units A, B, C, ... (S41), the outdoor unit detects the total operating current It by the first current transformer 41 (S42). Then, the total operating current It is subtracted from the breaker capacity Ib to obtain a current margin ΔA, and this current margin ΔA is compared with the heater current Ia of the electric heater (S).
43). The electric heater is energized only when the heater current Ia is smaller than the current margin ΔA (S
44).

In the conventional multi-type air conditioner described above, when controlling the total operating current It so that it is always equal to or less than the breaker capacity Ib, the energization of the electric heater, which is usually lower in energy efficiency than the compressor, is compressed. It is stopped in priority to the aircraft. Therefore, while improving energy efficiency,
It was possible to prevent the power breaker from operating.

[0005]

However, in the above-mentioned conventional multi-type air conditioner, the energization request to the electric heater generated on the indoor unit side is once transmitted to the outdoor unit side, and the outdoor unit based on the current margin ΔA. After making a decision as to whether or not to permit the energization of the electric heater, the decision is transmitted again to the indoor unit side so that the electric heater can be energized for the first time. Therefore, it takes a certain amount of time from the generation of the energization request until the energization is actually started, and there is a problem that the required quick warming property cannot be sufficiently obtained. Moreover, since the signal reciprocates between the indoor unit and the outdoor unit, noise is likely to be added during transmission to cause malfunction, and since control becomes complicated, it is difficult to easily obtain stable operation. There has been a problem that this is one of the causes of increasing costs in each of design, manufacturing, and maintenance work. Further, in the above-mentioned multi-type air conditioner, it is necessary to provide the current transformer 41 in the outdoor unit in order to detect the total operating current It, but this causes a problem that the number of parts increases and this causes a cost increase. .

The present invention has been made to solve the above-mentioned conventional drawbacks, and an object thereof is to make it unnecessary to detect an operating current in an outdoor unit, and to provide an electric heater. It is an object of the present invention to provide a multi-type air conditioner capable of promptly starting the energization after the occurrence of the energization request.

[0007]

Therefore, in the multi-type air conditioner of claim 1, one outdoor unit X provided with a compressor 1 is provided.
A plurality of indoor units A, B, C, and D having an indoor heat exchanger 15 and an electric heater 16 are connected to form a refrigeration cycle, and the indoor heat exchanger 15 functions as a condenser to perform heating operation. In the multi-type air conditioner that performs the above, during the heating operation, the operating current Ih of the compressor 1 is based on the operating frequency Hz of the compressor 1 and the high pressure of the refrigeration cycle.
Is grasped, and the energization to the electric heater 16 is controlled based on the operating current Ih.

In the multi-type air conditioner according to claim 1,
Since it is not necessary to detect the operating current in the outdoor unit X, the configuration can be simplified and the cost can be reduced.

The multi-type air conditioner according to a second aspect of the invention is characterized in that the high pressure of the refrigeration cycle is detected based on the condensation temperature Dc of the indoor heat exchanger 15.

In the multi-type air conditioner according to claim 2,
Since the high pressure is grasped by the indoor unit side, the structure thereof can be simplified and the electric heater 16 can be quickly energized.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Next, specific embodiments of the separation type air conditioner of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a diagram showing a refrigerant circuit of one embodiment of the multi-type air conditioner of the present invention. This multi-type air conditioner includes one outdoor unit (outdoor unit) X and four indoor units. It is configured by connecting units (indoor units) A, B, C, and D. As shown in the figure, the outdoor unit X includes a compressor 1 whose capacity is controlled by an inverter 1a and a variable compression capacity, and a four-way switch to a solid line side in the drawing during a cooling operation and a broken line side in the drawing during a heating operation. Switching valve 2,
The outdoor heat exchanger 3 having the blower fan 3a, the first motor-operated valve 4 for performing superheat degree control of the refrigerant during the heating operation while fully opening during the cooling operation, the liquid receiver 5, and the indoor units A to D described above. And a total of four second motor-operated valves 6 to 9 and an accumulator 10 for controlling the degree of superheat of the refrigerant during the cooling operation and controlling the degree of supercooling of the refrigerant during the heating operation. In addition, each device 1
The refrigerant pipes 11 and 10 are connected to each other so that the refrigerant can flow. Each of the indoor units A to D has an indoor heat exchanger 15 and an electric heater 16 that serves as an auxiliary heat source during heating operation or the like. The four indoor units A to D are connected to the one outdoor unit X by refrigerant pipes 18 ... And a refrigerant circulation circuit 19 is formed. In the figure, reference numeral 20 is a capillary tube. By returning the refrigerant in the liquid receiver 5 to the accumulator 10 by this capillary tube 20, the capillary tube 2
The evaporation temperature during the refrigeration cycle is detected at the 0 outlet. Further, 22 is a high pressure switch for detecting the discharge pressure of the refrigerant, 23 is a liquid closing valve, and 24 is a gas closing valve.

Further, FIG. 1 shows the indoor units A, B,
It is a functional block diagram which expands and shows one of C and D. As shown in the figure, the indoor unit includes an indoor heat exchanger 15, an electric heater 16, an indoor fan 15a composed of a cross flow fan, and a fan motor 15b for driving the indoor fan 15a. Further, in the figure, reference numeral 14 is a control unit, which exchanges data with the outdoor unit X through the signal line 14a, inputs the condensing temperature Dc from the heat exchange thermistor 17 provided for controlling the degree of subcooling, and outputs electricity. The energization of the heater 16 is turned on / off. The control unit 14 is composed of an integrated circuit including the functions of a microcomputer.

In the multi-type air conditioner configured as described above, the four-way switching valve 2 is switched to the side of the broken line to start the compressor 1, and the refrigerant is circulated in the refrigerant circulation circuit 19 as indicated by the broken line arrow. Then, the heating operation is performed. That is, while making the indoor heat exchanger 15 function as a condenser, the outdoor heat exchanger 3
To function as an evaporator, and thereby the outdoor heat exchanger 3
Thus, the heat absorbed from the outside air is released from the indoor heat exchanger 15 into the room. Immediately after the compressor 1 is started, the electric heater 16 is energized by the control of the control unit 14 of the indoor unit in order to improve the quick warming property and the use comfort. At this time, the total operating current It increases due to the electric current 1a supplied to the electric heater 16, so it is necessary to control the total operating current It so as not to exceed the breaker capacity Ib.

By the way, FIG. 4 is a graph showing the relationship between the operating frequency Hz of the compressor 1 and the high pressure during the heating operation as described above. Each of the characteristic curves 1 to 3 shows the case where the indoor units having different air conditioning capacities are operated. That is, the curve shows the case of operating an indoor unit (2.2 type) whose air conditioning capacity expressed in cooling capacity (kcal / h) is 2.2, and the curve shows the case of operating a 4.0 type similarly. , And the curves show the case of driving the 5.0 type, respectively. Furthermore, the curves ~ indicate the case where multiple indoor units are operated,
The curves are for driving the 3.2 and 4.0 types, the curves are for driving the 4.0 and 5.0 types, and the curves are for the 2.8 and 3.2 types. 3 and 4.0 type, respectively. As is clear from the above, the multi-type air conditioner can take various high pressure values depending on the type and number of indoor units operated at a constant operating frequency Hz of the compressor 1. Therefore, on the graph showing the relationship between the operating frequency Hz and the high pressure as shown in the figure, it is only possible to determine one point indicating the operating state of the multi-type air conditioner by specifying both of them. Become.

On the other hand, a plurality of straight lines drawn from the upper left side to the lower right side in FIG.
3 is an equal current line showing the input current I of FIG. As is clear from the figure, if one point on the graph is determined, the input current I of the compressor 1 corresponding to this is determined. For example, assume that the operating frequency Hz of the compressor 1 is now 60 Hz. If one 4.0-type indoor unit is operating at this time, the high pressure is approximately 2.15 MPa.
Will be understood as. Then, the point P on the graph is specified from both of these values, and the input current I of the compressor 1 at that time is found to be about 12A.
Further, if the 2.8 type, 3.2 type and 4.0 type indoor units are operating at this time, the above high pressure will be grasped as about 1.3 MPa. The point is identified and the input current of compressor 1 is found to be about 9A.

FIG. 3 is a flow chart showing energization control of the electric heater 16 by the control unit 14 in a predetermined indoor unit, which utilizes the above-described principle shown in FIG. When this control routine is started, first, in step S1, it is determined whether or not a request to energize the electric heater 16 is generated in the indoor unit. Then, if the energization request is generated, then in step S2, the operating frequency Hz and the condensation temperature Dc are grasped. This operating frequency Hz is the same as the signal line 14a.
Is transmitted from a control device (not shown) of the outdoor unit X through, and the condensing temperature Dc is input from the heat exchange thermistor 17. And this condensation temperature D
The above-mentioned high pressure is grasped based on c, and the input current I of the compressor 1 is further obtained.
In 3. That is, the input current I is estimated by the following equation (1) I = A + αHz + βDc (1). Here, A: Indoor unit model specific value (3.5) α: Coefficient (0.14) Hz: Operating frequency β: Coefficient (0.0224) Dc: Condensation temperature. The operating current I estimated using the above equation is compared with the electric heater permission current Imax in step S4. This electric heater permission current Imax is equal to the electric heater 1
6 is the maximum input current of the compressor 1 capable of permitting energization to 6, and the following equation (2) (electric heater permission current) = (breaker capacity)-(electric component current such as fan)-(heater current) ) ... It is required by (2). For example, the breaker capacity is 20A,
If the electric component current is 1 A and the heater current is 2.5 A, then Imax = 16.5 A. When the electric heater permission current Imax is larger than the input current I, the process proceeds to step S5 to energize the electric heater 16, while otherwise returns to step S1.

On the other hand, in the cooling operation of the multi-type air conditioner having the above-mentioned configuration, the four-way switching valve 2 is switched to the solid line side to start the compressor 1 and the refrigerant is shown in the refrigerant circulation circuit 19 by the solid line arrow. Cycle into That is, the outdoor heat exchanger 3 is made to function as a condenser while the indoor heat exchanger 15 is made to function as an evaporator, so that the heat absorbed from the room in the indoor heat exchanger 15 is released to the outdoor air by the outdoor heat exchanger 3. To do.

In the multi-type air conditioner that operates as described above, during the heating operation, when the operation of the refrigeration cycle alone cannot provide sufficient heating capacity, such as immediately after the start of activation of the compressor 1, By energizing the electric heater 16, this can be used as an auxiliary heat source to improve air-conditioning comfort. In this case, it is necessary to energize the electric heater 16 so that the total operating current It does not exceed the breaker capacity Ib. However, in the multi-type air conditioner, the operating frequency Hz of the compressor 1 and the indoor heat exchanger 15 are increased. The input current I of the compressor 1 is known from the condensing temperature Dc. Therefore, it is not necessary to provide a current detecting means such as a current transformer in the outdoor unit X, so that the number of parts can be reduced and the cost can be reduced. Also outdoor unit X
Using the operating frequency Hz input from the electric heater 16
To determine whether to permit energization to the indoor units A, B,
Since it can be performed on the C and D sides, the indoor unit A,
It is possible to quickly perform from the generation of the energization request in B, C, and D to the actual energization, thereby improving the use comfort. Moreover, the operating frequency Hz is originally commanded by the controller of the outdoor unit X, and the heat exchange thermistor 17 for detecting the condensation temperature Dc is used.
Since it is provided in advance for controlling the degree of supercooling, it is not necessary to add a special member or the like, and therefore these do not contribute to an increase in the cost of the device.

Although the specific embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments, and various modifications can be carried out within the scope of the present invention. For example, in the above-mentioned multi-type air conditioner, the high pressure is grasped based on the condensation temperature Dc of the indoor heat exchanger 15, but this high pressure is the condensation pressure or the compressor 1.
Alternatively, it may be grasped based on the discharge pipe temperature. However, in this case, the former requires a pressure sensor, and the latter requires transmission of the discharge pipe temperature data from the outdoor unit X, so that the configuration may be complicated. However, if it is more convenient to have the above configuration due to the fact that the heat exchanger thermistor 17 is not provided in advance, there is no obstacle to doing so. Further, although the compressor 1 having a variable compression capacity is used in the multi-type air conditioner, a compressor having a constant compression capacity that is driven at a commercial frequency may be used. Even if the present invention is applied to, the same effect as described above can be obtained.

[0021]

In the multi-type air conditioner according to the first aspect, it is not necessary to detect the operating current in the outdoor unit, so that the structure can be simplified and the cost can be reduced.

According to the multi-type air conditioner of claim 2,
Since the high pressure is grasped by the indoor unit side, the structure can be simplified and the electric heater can be quickly energized.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of an indoor unit of a multi-type air conditioner according to an embodiment of the present invention.

FIG. 2 is a refrigerant circuit diagram of the multi-type air conditioner.

FIG. 3 is a flowchart showing an operation of a control unit of the multi-type air conditioner.

FIG. 4 is a graph showing the relationship between the operating frequency of the compressor and the high pressure.

FIG. 5 is a power supply side circuit diagram of a conventional multi-type air conditioner.

FIG. 6 is a flowchart showing the operation of a conventional multi-type air conditioner.

[Explanation of symbols]

 1 Compressor 15 Indoor heat exchanger 16 Electric heater

Claims (2)

[Claims] 1. An indoor heat exchanger (15) and an electric heater (16) in one outdoor unit (X) equipped with a compressor (1).
And a plurality of indoor units (A), (B), (C), and (D) provided with are connected to form a refrigeration cycle, and the indoor heat exchanger (1
In a multi-type air conditioner that performs heating operation by causing 5) to function as a condenser, during the heating operation, based on the operating frequency (Hz) of the compressor (1) and the high pressure of the refrigeration cycle, A multi-type air conditioner characterized in that the operating current (Ih) of the compressor (1) is grasped, and the energization of the electric heater (16) is controlled based on the operating current (Ih). 2. The multi-type air conditioner according to claim 1, wherein the high pressure of the refrigeration cycle is grasped based on a condensation temperature (Dc) of the indoor heat exchanger (15).