JP3386700B2 - Control method when the number of indoor units operating changes in multi-room air conditioner - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-room air conditioner in which a plurality of indoor units are connected to one outdoor unit, and more specifically, the total required load from the inside of the room is increased by increasing the number of operating indoor units. Control method when increased.

[0002]

2. Description of the Related Art In recent years, a multi-room air conditioner in which a plurality of indoor units are connected to one outdoor unit has been accepted by general household consumers in terms of space saving and aesthetics. is there. In addition, compared to installing multiple sets of one-room air conditioners in which one indoor unit is connected to one outdoor unit, the multi-room air conditioner is advantageous in terms of cost, so Demand is gradually increasing.

In this multi-room air conditioner, the capacity of the compressor is controlled according to the sum of the required capacities of the indoor units, and the opening of the flow rate adjusting valve provided in the liquid pipe connected to each indoor unit is controlled. It is controlled individually according to the required capacity of the corresponding indoor unit.

However, in such a multi-room air conditioner, since the opening control of each flow rate adjusting valve is separated for each indoor unit, there is a large difference in the required capacity of each indoor unit during heating operation. In some cases, it caused various problems.

For example, since the flow rate control by the flow rate adjusting valve is performed on the downstream side of each indoor unit, a large amount of liquid refrigerant tends to accumulate in the indoor unit having a small required capacity, and the refrigerant circulation amount of the entire refrigeration cycle becomes insufficient. Due to the shortage of the circulation amount of the refrigerant, there has been a situation in which the degree of superheat of the refrigerant in the refrigerant heater cannot be controlled to be constant only by controlling the opening degree of each electric expansion valve.

In order to solve such a situation, the heating amount of the refrigerant heater is reduced to lower the heating capacity, or the minimum limit opening of the flow rate adjusting valve is increased to obtain a large heating capacity ratio of each indoor unit. There was a problem that the specifications of the air conditioner would be reduced if it was lost.

In view of these problems, Japanese Patent Laid-Open No. 5-26
Japanese Patent No. 530 discloses an air system capable of always maintaining a proper heating capacity by controlling the refrigerant superheat degree of a heat source side outdoor heat exchanger to a predetermined value even when there is a large difference in heating requirements for indoor units. We provide a harmony machine.

This air conditioner is provided with a refrigerant heater having a gas burner, a combustion fan, a proportional valve, an igniter, a flame detector, etc., and heats the refrigerant by the combustion flame of the gas burner during heating operation. . Also, during heating operation, when the difference in required capacity is larger than the set value, the two-way valve corresponding to the one with the larger required capacity of the indoor unit is opened and the two-way valve corresponding to the smaller one is closed, and each indoor heat exchange is performed. The opening of the flow rate adjusting valve is controlled so that the temperature of the refrigerant flowing into the container has a predetermined relationship based on the required capacity of each indoor unit. Further, the opening degree of each electric expansion valve is controlled while keeping the total opening degree of each electric expansion valve constant so that the degree of subcooling in each indoor heat exchanger becomes equal.

[0009]

Recently, a petroleum-refrigerant heating type multi-room air conditioner, which is advantageous in terms of economy, has been studied, but a plurality of indoor units are connected to one outdoor unit. The multi-chamber air conditioner has a problem in that the amount of refrigerant used is large and the control of the petroleum refrigerant heater is not easy as compared with the case of heating the refrigerant by the combustion flame of the gas burner. In particular, it is important to control the balance between the heating amount and the refrigerant circulation amount, and in a multi-room air conditioner,
If the amount of refrigerant circulation fluctuates greatly and the amount of heating is greater than the amount of refrigerant circulation, it causes problems such as abnormal temperature of the refrigerant heater and rise in exhaust heat temperature, while if the amount of refrigerant circulation is larger than the amount of heat, the reliability of the compressor is increased. There is a problem that the input is lowered or the input is increased.

Further, since a material having a large heat capacity such as aluminum is used for the combustor of the petroleum refrigerant heater, the heating amount of the refrigerant is easily controlled because the refrigerant heating amount does not fluctuate even if the combustion amount is largely changed. is not.

In particular, when the number of operating indoor units changes, the total required load from the inside of the room fluctuates greatly, and there is a problem that the balance between the heating amount and the refrigerant circulation amount tends to collapse.

The present invention has been made in view of the above problems of the prior art. Even when the number of operating indoor units is increased, an efficient combustion amount and a refrigerant corresponding to the required load from the room are provided. An object of the present invention is to provide a control method when the number of operating indoor units of a multi-room air conditioner capable of controlling the circulation amount changes.

[0013]

In order to achieve the above object, the invention according to claim 1 of the present invention comprises a variable capacity compressor, a four-way valve, an outdoor heat exchanger and a refrigerant heater. A liquid-side branch pipe obtained by branching a single outdoor unit having the same and a plurality of indoor units having an indoor heat exchanger connected in parallel from the liquid-side main pipe provided in the outdoor unit and through which the refrigerant liquid mainly flows. And an electric expansion valve, which is provided in the outdoor unit and is connected via a gas side branch pipe branched from a gas side main pipe through which a refrigerant gas mainly flows, and whose valve opening degree can be electrically controlled, is attached to the liquid side branch pipe. At the same time, an indoor temperature setting means for arbitrarily setting the temperature of the room in which each indoor unit is installed, an indoor temperature detecting means for detecting the indoor temperature, a temperature set by the indoor temperature setting means, and the indoor temperature detecting means. Temperature calculation to calculate the temperature difference between the room temperature detected by A stage, a rated capacity storage means for storing the rated capacity of each of the indoor units, and a frequency / combustion amount calculation means for calculating the frequency of the compressor and the target combustion amount of the refrigerant heater for each predetermined cycle. This is a control method when the number of operating indoor units of a multi-room air conditioner changes, and when the total required load from the interior increases due to an increase in the number of operating indoor units during heating operation, the compressor frequency is gradually increased. The amount of refrigerant circulation is increased by a predetermined amount of time, and after a lapse of a predetermined time, the electric expansion valve corresponding to the indoor unit receiving the operation signal is controlled to be opened, and the combustion amount of the refrigerant heater is gradually increased. Is a control method when the number of operating indoor units of the multi-room air conditioner changes.

The invention according to claim 2 is characterized in that the indoor fan of the indoor unit that receives the operation signal is operated at the same time as the increase of the refrigerant circulation amount or after a delay of a predetermined time.

The invention according to claim 3 is characterized in that the increasing rate of the combustion amount of the refrigerant heater is set smaller than the increasing rate of the compressor frequency.

Further, the invention according to claim 4 is characterized in that the combustion amount of the refrigerant heater is increased stepwise and the average increase rate is set smaller than the increase rate of the compressor frequency.

The invention according to claim 5 is characterized in that the opening control of the electric expansion valve and the increase of the combustion amount of the refrigerant heater are simultaneously performed.

Further, the invention according to claim 6 is characterized in that the amount of combustion in the refrigerant heater is increased with a delay from the opening control of the electric expansion valve.

Further, in the invention described in claim 7, the compressor frequency is set to a value equal to or larger than a value calculated by the frequency / combustion amount calculating means to increase the refrigerant circulation amount. Is characterized by.

Further, in the invention according to claim 8, the compressor frequency is reduced to a value calculated by the frequency / combustion amount calculating means after a predetermined time has elapsed since the combustion amount of the refrigerant heater was increased. Is characterized by.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an example of a refrigeration cycle diagram of a multi-room air conditioner according to the present invention,
A plurality of (for example, two) indoor units 4a in one outdoor unit 2,
The case where 4b is connected is shown.

In FIG. 1, an outdoor unit 2 has an inverter-driven variable capacity (frequency) type compressor 6 (hereinafter simply referred to as a compressor), an outdoor heat exchanger 8, and a four-way valve 1 for switching between heating and cooling.
0 is provided, while indoor heat exchangers 12a and 12b are provided in the indoor units 4a and 4b, respectively. Also,
The outdoor unit 2 and the indoor units 4a, 4b are divided into liquid side branch pipes 16a, 16 branched from a liquid side main pipe 14 provided in the outdoor unit 2.
b and the gas side branch pipes 20a and 20b branched from the gas side main pipe 18 provided in the outdoor unit 2,
The liquid side branch pipes 16a and 16b are provided with an electric expansion valve 22 whose valve opening can be pulse-controlled by, for example, a stepping motor or the like.
a and 22b are respectively interposed.

Further, a refrigerant heating pipe 26 branching from the liquid side main pipe 14 and having a two-way valve 24 attached thereto is wound around a refrigerant heater 28. The refrigerant heating pipe 26 is connected to the compressor 6. It communicates with an accumulator 30 provided on the suction side through a suction pipe 31. An electromagnetic pump 32 for supplying a predetermined amount of fuel oil to the refrigerant heater 28 is provided near the refrigerant heater 28, and a burner motor 34 for supplying combustion air to the refrigerant heater 28 includes a refrigerant heater 28. Is provided adjacent to. In addition, the indoor units 4a and 4b have indoor temperature sensors 36a and 36b that detect the room temperature of the room in which the indoor units 4a and 4b are installed, and an operation mode (cooling or heating) and room temperature that the occupant desires. Operation setting circuits 38a and 38b capable of setting operation or stop are provided. In the figure, 42 and 44 are check valves, and 46 is an auxiliary throttle.

In the refrigeration cycle having the above structure, during cooling, the refrigerant discharged from the compressor 6 flows from the four-way valve 10 to the outdoor heat exchanger 8 where it exchanges heat with outdoor air to be condensed and liquefied. Next, the pressure is reduced by passing through the auxiliary throttle 46, and the refrigerant easily evaporates.
It branches to the liquid side branch pipes 16a and 16b. The valve openings of the electric expansion valves 22a and 22b are controlled by the control method described later so as to have openings corresponding to the respective rooms, so that the refrigerant also becomes a low pressure at a flow rate corresponding to each load and the indoor heat is reduced. After flowing to the exchangers 12a and 12b and evaporating, they pass through the gas side branch pipes 20a and 20b, the gas side main pipe 18 and the four-way valve 10, and are again sucked into the compressor 6 via the accumulator 30. Further, the compressor frequency is determined by a control method described later according to the total load level.

On the other hand, when the heating operation is started, the two-way valve 24 is initially closed for a predetermined time, so that the refrigerant from the check valve 42 to the check valve 44 via the outdoor heat exchanger 8 is compressed by the compressor 6. Recovered (refrigerant recovery cycle). When the refrigerant recovery cycle ends, the two-way valve 24 opens, and the high-temperature and high-pressure refrigerant discharged from the compressor 6 passes through the four-way valve 10 and branches from the gas-side main pipe 18 to the gas-side branch pipes 20a and 20b. , To the indoor heat exchangers 12a and 12b to be condensed and liquefied, and the electric expansion valve 22a on the liquid side branch pipes 16a and 16b,
The pressure is reduced at 22b to an intermediate pressure. Electric expansion valve 22a,
The valve opening degree of 22b is controlled to be an opening degree commensurate with the load of each room by the control method described later similarly to the case of cooling, so that the refrigerant also has a flow rate corresponding to each load in the indoor heat exchanger. It flows through 12a and 12b. The intermediate pressure refrigerant is guided from the liquid side main pipe 14 to the refrigerant heating pipe 26, and further to the refrigerant heater 28 via the two-way valve 24. Since the refrigerant heater 28 is controlled by the heating method described later, the refrigerant which is gasified by being heated to a predetermined temperature by the refrigerant heater 28 is sucked into the compressor 6 again via the accumulator 30.

Next, a method of controlling the compressor frequency, the combustion amount and the electric expansion valve opening degree will be described. FIG. 2 is a block diagram showing the flow of control of the compressor frequency, the combustion amount, and the electric expansion valve opening, and FIG. 3 is a temperature zone division diagram of the temperature difference ΔT between the indoor temperature Tr and the set temperature Ts.

First, in the indoor unit 4a, the output (indoor temperature) of the indoor temperature sensor 36a is sent from the indoor temperature detection circuit 48 as a temperature signal to the differential temperature calculation circuit 50, and the setting determination circuit 52 operates the operation setting circuit 38a. The set temperature and operation mode set in step 3 are discriminated and sent to the temperature difference calculation circuit 50, where the temperature difference ΔT (= Tr−Ts) is calculated,
Frequency No. shown in. Is converted into the differential temperature signal.

Further, in the ON-OFF discrimination circuit 54, the operation of the indoor unit 4a set by the operation setting circuit 38a (O
N) or stop (OFF) is determined. Further, the rated capacity of the indoor unit 4a is stored in the rated capacity storage circuit 56, and the rated capacity signal, the differential temperature signal, the operation mode signal, and the ON-OFF determination signal are sent from the signal sending circuit 58 to the signal of the outdoor unit 2. It is sent to the receiving circuit 60. A similar signal is sent from the indoor unit 4b to the signal receiving circuit 60. The signal received by the signal receiving circuit 60 is sent to the compressor frequency / combustion amount calculating circuit 62 and the expansion valve opening calculating circuit 64. However, when different operation mode signals are present, the operation mode of the indoor unit that first started operation is prioritized, and it is considered that the indoor units in different operation modes are stopped, and the ON-O
The FF discrimination signal is sent OFF.

In the compressor frequency / combustion amount calculation circuit 62, the rated capacity signal and the differential temperature signal of the indoor units 4a and 4b,
The load level coefficient is read from the load coefficient table 66 shown in Table 1 below from the operation mode signal and the ON-OFF determination signal, the sum of the load level coefficients is multiplied by a constant, and the correction value is added to determine the frequency of the compressor 6. decide.

[Table 1]

More specifically, in the cooling / drying operation, the frequency N which is a temperature difference signal between the two indoor units 4a and 4b
o. From the load coefficient table 66, the respective load level coefficients Ln1 and Ln2 are obtained, the total indoor load level Lnφ is derived by calculation, and the value is set to the operating frequency of the compressor 6 to be requested by the outdoor unit 2. Perform initial settings.

On the other hand, in the heating operation, the frequency Nos. Of the two indoor units 4a and 4b are set. From the load coefficient table 66, the respective load level coefficients Ln1 and Ln2 are calculated, and the indoor total load level Lnφ is derived by calculation. The value is set as the load level Lnk of the outdoor unit 2, and this outdoor operation load level Lnk is set. Is set to the operating frequency of the compressor 6 to perform the initial setting required for the outdoor unit 2. A. Control calculation formula for cooling / drying operation 1) Single room operation Lnφ = a1 × (Ln1 or Ln2) + b1 2) Double room operation (i) Ln1 + Ln2 <34 Lnφ = a1 × (Ln1 + Ln2) + b1 (Ii) When Ln1 + Ln2 ≧ 34, Lnφ = a2 × (Ln1 + Ln2) + b2 where a1> a2, b1 <b2 Lnφ obtained from the above control calculation formula is set as the operating frequency of the compressor 6. Comp Hz = Lnφ B. Control calculation formula for heating operation 1) In the case of one room Lnφ = a3 × (Ln1 or Ln2) + b3 2) In the case of two rooms Lnφ = a4 × (Ln1 + Ln2) + b4 However, a3> a4, b3 <b4

Lnφ obtained from the above control calculation formula is L
Replace with nk and set the value of Lnk to the operating frequency of the compressor 6. Lnk = Lnφ, Comp Hz = Lnk Note that the above a1 to a4 and b1 to b4 are experimental values determined by the capacity of the compressor 6, the pipe diameter, and the like.

4 and 5, a1 = 30/12, b1
= -8, a2 = 13/12, b2 = 37, a3 = 15 /
17 is a graph showing the above control calculation formula when 17, b3 = 0.5, a4 = 5/13, and b4 = 25.2.

As shown in FIG. 4, the minimum operating frequency of the compressor 6 during the single room operation during the cooling / drying operation is 28.
The maximum operating frequency is set to 98 Hz while the minimum operating frequency of the compressor 6 in the case of the two-room operation is set to 32 Hz while the low frequency protection does not operate.

Further, as shown in FIG. 5, the minimum operating frequency of the compressor 6 in the one-room and two-chamber operation during the heating operation is set to 20 Hz and 41 Hz, respectively, while the maximum operating frequency is set to 49 Hz and It is set to 61 Hz. As an example, the case where the signals from the indoor units 4a and 4b are shown in Table 2 below will be described.

[Table 2] From Table 1 and Table 2, the load level coefficient L of the indoor units 4a, 4b
n1 and Ln2 are 34 and 31, respectively, and the compressor 6
The frequency Hz is: Hz = Lnφ = 5/13 × (34 + 31) + 25.2≈
50. The result of this calculation is sent as a frequency signal to a compressor drive circuit (not shown) to control the frequency of the compressor 6. After that, the rated capacity signal, the differential temperature signal, the operation mode signal, and the ON-OF of each of the indoor units 4a and 4b are set every predetermined period.
From the F discrimination signal, the compressor frequency / combustion amount calculation circuit 62 of the outdoor unit 2 performs calculation, corrects the calculation result as necessary,
The corrected value is sent as a frequency signal to the compressor drive circuit to control the frequency of the compressor 6.

In this way, the frequency of the compressor 6 is determined by a predetermined calculation formula according to the number of operating machines, and the compressor 6 should be operated at a lower operating frequency in low frequency operation during single room operation. The low input operation becomes possible, and by operating the compressor 6 at a high operating frequency as the total load level increases, a higher refrigerant circulation amount is secured in consideration of the pressure loss due to the piping, and high efficiency operation is realized. There is. Further, during the two-room heating operation, even if the indoor required load is the same as the one-room operation, the volume of the pipe for carrying the refrigerant is large, and therefore it is necessary to operate at a higher frequency. However, from a certain point, the pipe pressure loss in the single-chamber operation becomes very large, and therefore, it is necessary to set the compressor frequency higher in the single-chamber operation.

Similarly, in the expansion valve opening calculation circuit 64, Table 3 is obtained from the rated capacity signal, the temperature difference signal, the operation mode signal, and the ON-OFF discrimination signal of each indoor unit 4a, 4b.
A load level coefficient is selected from the load coefficient table 66 shown in FIG. 4 and is read from the valve initial opening table 70 for each rated capacity shown in Table 4 below based on the rated capacity of each indoor unit 4a, 4b. The initial valve opening is determined so that each indoor unit can perform a predetermined capacity control even if indoor units having different rated capacities are combined.

[Table 3]

[Table 4]

The valve opening degrees of the electric expansion valves 22a and 22b are obtained by multiplying the respective load level coefficients by the valve initial opening degree. Expansion valve opening = P0 (load level coefficient) x initial pulse

Similar to the case of calculating the compressor frequency, the case where the signals from the indoor units 4a and 4b are shown in Table 2 will be described.
The load level coefficients of the indoor units 4a and 4b are each 0.95.
And 0.85, and the initial valve opening is 180
And 230. Therefore, the electric expansion valves 22a, 2
The valve openings of 2b are 171, 219 (the first decimal place
Round to the nearest). The result of this calculation is sent to an expansion valve drive circuit (not shown) as an expansion valve opening signal.

Therefore, the valve opening degrees of the electric expansion valves 22a and 22b become 171 pulses and 219 pulses, respectively, and thereafter, at every predetermined cycle, a differential temperature signal, an operation mode signal,
The valve opening degrees of the electric expansion valves 22a and 22b are calculated from the ON-OFF discrimination signal, and the calculation results of these are corrected if necessary, and then sent to the expansion valve drive circuit as an expansion valve opening signal.

Next, the control of the combustion amount during heating will be described together with the problems peculiar to the multi-room air conditioner. The refrigerant outlet temperature of the refrigerant heater 28 during heating is temperature balanced by the relationship between the temperature of the refrigerant heater 28 (combustion amount) and the temperature of the refrigerant flowing through the pipe (refrigerant circulation amount), and the combustion amount is higher than the refrigerant circulation amount. When it is larger, the refrigerant outlet temperature rises, while when the combustion amount is smaller than the refrigerant circulation amount, the refrigerant outlet temperature falls. Such a phenomenon occurs in a multi-room air conditioner,
It occurs for the following reasons. The change width of the connected pipe length is large, the change of the refrigerant circulation amount with respect to the change of the pipe length is large, and the refrigerant outlet temperature of the refrigerant heater changes greatly. -Since the amount of the enclosed refrigerant is large, the change in the amount of the refrigerant is large, and especially when the number of operating vehicles changes, the amount of refrigerant circulation changes greatly. This change in the refrigerant circulation amount has a delicate influence on the temperature of the refrigerant heater.・ The change in the refrigeration cycle due to the maximum capacity operation is larger than that of the single room air conditioner. Further, fine adjustment control by minimum capacity operation is required, the balance between the combustion amount and the refrigerant circulation amount is likely to be lost during the refrigeration cycle control, and the refrigerant temperature greatly changes.

Further, the following problems may occur due to the rise or fall of the refrigerant outlet temperature. (I) When the refrigerant outlet temperature rises: The capacity is reduced (heat exchanger efficiency is reduced). -When the temperature rises significantly, the refrigerant heater and compressor are stopped to protect the refrigerant heater and compressor. as a result,
Repeated ON-OFF control of the burner shortens the life of the heater or relay or deteriorates comfort. -If the temperature rises abnormally, the oil in the refrigeration cycle will be carbonized, making it impossible to lubricate the compressor, and the compressor will malfunction. Further, the aluminum of the refrigerant heater main body and the copper tube wound around the heater may be deformed. -Exhaust gas temperature rises. (Ii) When the refrigerant outlet temperature decreases ・ Compressor liquid compression (liquid back) due to a decrease in superheat
Shaft wear due to. -Condensation may occur inside the refrigerant heater, and the condensed water may mix with sulfur to generate sulfuric acid, which may cause aluminum corrosion.・ Increased input.

In order to avoid the above problem, in the multi-room air conditioner according to the present invention, the combustion amount control is performed as follows. In each of the indoor units 4a and 4b, the frequency No. Is set and output to the outdoor unit 2. In the outdoor unit 2, each indoor unit 4a, 4b
Frequency No. And load rank coefficient Ln from ability rank
1 and Ln2 are derived to calculate the total load level Lnφ.
Further, the calculated Lnφ is replaced with Lnk, and the outdoor operation load level is calculated from Lnk to the target value of the combustion amount (K
Value) is calculated by the following formula. -Determination of target value 1) Combustion amount during one-chamber operation K =-(256-K1 _max ) / (Lnk1 _max -Lnk1
_min ) x (Lnk-Lnk1 _min ) + 256 2) Combustion amount K = -K2 _min / (Lnk2 _max- Lnk2 _min ) x (L
nk-Lnk2 _min ) + K2 _min

Here, K1 _max , K2 _min , Lnk
1 _min , Lnk1 _max , Lnk2 _min , and Lnk2 _max are determined as follows, for example. K1 _max : 69 K2 _min : 145 Lnk1 _min : 20 Lnk1 _max : 42 Lnk2 _min : 42 Lnk2 _max : 61

FIG. 6 is a graph of the above control calculation formula. In consideration of the target value of the combustion amount corresponding to the refrigerant circulation amount, for example, the kerosene oil feed amount which becomes the combustion amount as shown in FIG. To decide. That is, when the target value of the combustion amount is calculated, the frequency of the electromagnetic pump 32 and the rotation speed of the burner motor 34 are initialized according to the calculated target value of the combustion amount, and the appropriate kerosene oil feed amount and air amount are set. To set.
Moreover, the frequency No. of each indoor unit 4a, 4b. From the electric expansion valves 22a, 22b connected to the indoor units 4a, 4b
Since the initial setting is performed, the control of the compressor frequency is the same as the control method for cooling. Further, the determination of the combustion amount can be performed in the same drive range of the compressor frequency and the same initial setting as the compressor frequency.

Here, the relationship between the maximum combustion amount of one chamber and the minimum combustion amount of two chambers is set so that the smaller the number of operating units, the higher the combustion amount at the same compressor frequency. This is because the pipe pressure loss with respect to the refrigerant circulation amount is larger in the one-chamber operation, and it is necessary to increase the combustion amount in the one-chamber operation at the same compressor frequency.

In this way, the compressor frequency is controlled according to the total required capacity of each room, and the opening degree of each electric expansion valve 22a, 22b is determined according to the load of each room. Ability can be distributed to the required rooms. Therefore, it is possible to improve comfort and save energy while finely and optimally controlling the refrigeration cycle.

Next, regarding the change control of the number of operating units when one of the indoor units 4a and 4b is initially in heating operation and the other one is in heating operation thereafter, the flowchart of FIG. 8 and the timing chart of FIG. Will be described with reference to.

The rooms in which the indoor units 4a and 4b are installed are A room and B room. Only the indoor unit 4a in the A room starts the heating operation of the indoor unit 4b in the B room, and immediately after the start. When the electric expansion valve 22b corresponding to the B room is controlled to be opened, the refrigerant starts flowing not only to the indoor unit 4a of the A room but also to the indoor unit 4b of the B room, and the amount of the refrigerant flowing through the refrigerant heater 28 decreases. As a result, the balance between the heating amount and the refrigerant circulation amount may be lost, and the refrigerant outlet temperature of the refrigerant heater 28 may rise abnormally.

In order to avoid such an abnormal rise in the refrigerant temperature, when the operation signal for the indoor unit 4b in the room B is received during the heating operation of the room A (step S1) (step S2), the indoor fan of the indoor unit 4b is received. Is operated (step S3) and the compressor frequency is gradually increased to a high frequency of 61 Hz or a value determined from the required load in the room (step S4) to increase the refrigerant circulation amount first. Further, the elapsed time T1 from the time of receiving the operation signal is counted, and when T1 reaches a predetermined time (for example, 30 seconds) (steps S5 and S6), the electric expansion valve 22b corresponding to the indoor unit 4b is controlled to be opened. Along with (step S7), the frequency of the electromagnetic pump 32 and the rotation speed of the burner motor 34 are gradually increased (steps S8 and S9) to gradually increase the combustion amount of the refrigerant heater 28. The frequency of the electromagnetic pump 32 and the rate of increase of the rotational speed of the burner motor 34 are set so that the refrigerant temperature does not rise abnormally.
It is set smaller than the frequency increase rate. The combustion amount may be increased at the same time as the opening control of the electric expansion valve 22b or with some delay, but if it is increased before the opening control of the electric expansion valve 22b, the combustion amount of the refrigerant heater 28 is also increased. There is a risk that the refrigerant outlet temperature will rise abnormally.

Further, the elapsed time T from the reception of the driving signal
When 2 reaches a predetermined time (for example, 180 seconds) (steps S10 and S11), the compressor frequency is stepwise reduced to a value determined from the indoor required load.

In the flowchart of FIG. 8 and the timing chart of FIG. 9, the compressor frequency is raised and the indoor fan is operated at the same time. However, the indoor fan is turned on after a predetermined time has elapsed from the compressor frequency rising timing. It can also be activated. Also, the refrigerant heater 2
Although the combustion amount of 8 is gradually increased, the combustion amount may be increased stepwise. In this case, if the average increase rate (increase rate) of the combustion amount is made smaller than the increase rate of the compressor frequency. Good.

Next, regarding the control for changing the number of operating units when the indoor units 4a and 4b in the room A and the room B are both in the heating operation and the indoor unit 4b in the room B is stopped, the flowchart of FIG. 10 and the timing chart of FIG. Will be described with reference to.

During the two-room heating operation of the room A and the room B (step S21), when the stop signal of the indoor unit 4b is received (step S22), the frequency of the electromagnetic pump 32 and the rotation speed of the burner motor 34 are gradually reduced. Is controlled so that the combustion amount of the refrigerant heater 28 is reduced (step S23).
And S24). Further, the elapsed time T1 from the time when the stop signal of the indoor unit 4b is received is counted, and when T1 reaches a predetermined time (for example, 60 seconds) (steps S25 and S2).
6) The opening degree of the electric expansion valve 22b corresponding to the indoor unit 4b is controlled in the closing direction (step S27).

Furthermore, the elapsed time T from the reception of the stop signal
2 reaches a predetermined time (for example, 90 seconds) (step S
28 and S29), the indoor fan of the indoor unit 4b is stopped (step S30), and the elapsed time T from when the stop signal is received is T.
When 3 reaches a predetermined time (for example, 210 seconds) (steps S31 and S32), the compressor frequency is reduced stepwise to the value calculated by the compressor frequency / combustion amount calculation circuit 62 based on the total indoor load demand. By reducing the refrigerant circulation amount, the heating amount and the refrigerant circulation amount are balanced, and the abnormality of the refrigerant outlet temperature of the refrigerant heater 28 is avoided.

The delay time for stopping the indoor fan depends on the heat capacity of the combustor, and if the heat capacity of the combustor is large, it is necessary to lengthen the delay time.

FIGS. 12 to 15 are graphs showing various data when the number of operating units changes in the multi-room air conditioner according to the present invention. FIGS. 12 and 13 show from one-room operation to two-room operation. 14 and 15 show the case where the operation is switched to the operation, and the case where the operation is switched from the two-room operation to the one-room operation.

More specifically, FIG. 12 shows a case where another indoor unit having a rated capacity of 2.2 kw operates while an indoor unit having a rated capacity of 3.2 kw is operating. Specifications such as the target value (K value) are changing as follows. 2.2kw: ON, 3.2kw air volume: Hi, compressor frequency: 36 → 61Hz 2.2kw valve opening: 80 → 350, combustion amount (K value):
98 → 80 Compressor frequency: 61 → 54Hz

As shown in FIG. 12, from one room operation to 2
Due to switching to room operation, the high pressure at the compressor outlet, which affects the refrigerant circulation amount, changes (decreases) significantly from to, but the compressor frequency is increased to 61 Hz and a new delay is made to start anew. While controlling the opening of the electric expansion valve corresponding to the indoor unit, the frequency of the electromagnetic pump is gradually increased to increase the combustion amount, so that the balance between the refrigerant circulation amount and the combustion amount is not greatly disturbed.
Although the suction temperature of the compressor (the outlet temperature of the refrigerant heater) and the discharge temperature are slightly lowered, no extreme decrease is observed.

FIG. 13 shows a case where another indoor unit having a rated capacity of 3.2 kw operates while an indoor unit having a rated capacity of 2.2 kw is operating, and the target values of the compressor frequency and the combustion amount ( Specifications such as K value) are changing as follows. 3.2 kw: ON, compressor frequency: 24 → 61 Hz 3.2 kw valve opening: 80 → 480-combustion amount (K value): decrease in steps from 40

As shown in FIG. 13, the combustion amount greatly changes as the frequency of the electromagnetic pump increases stepwise, but the compressor frequency was increased to 61 Hz before the increase of the electromagnetic pump frequency. After that, since the electric expansion valve corresponding to the newly started indoor unit is controlled to open, the high pressure does not fluctuate significantly, and the suction temperature and the discharge temperature do not fluctuate extremely.

FIG. 14 shows the rated capacities of 2.2 kw and 3.2 kw.
The figure shows the case where the indoor unit with the rated capacity of 2.2 kw stopped during the operation of the two indoor units, and the specifications of the compressor frequency and the target value (K value) of the combustion amount changed as follows. is doing. Combustion amount (K value): 80 → 98 2.2kw Valve opening: 350 → 80 2.2kw: OFF, 3.2kw Air volume: Lo Compressor frequency: 48 → 42Hz

As can be seen from FIG. 14, the high-pressure fluctuation is large, but by controlling each device based on the timing chart of FIG. 11, rapid fluctuations of the suction temperature and the discharge temperature are suppressed.

FIG. 15 shows the rated capacities of 2.2 kw and 3.2 kw.
The figure shows a case in which the indoor unit with a rated capacity of 3.2 kw stopped during operation of the two indoor units, and the specifications of the compressor frequency and the target value (K value) of the combustion amount changed as follows. is doing. Combustion amount (K value): 40 → maximum value 3.2kw Valve opening: 480 → 80 3.2kw: OFF Compressor frequency: 58 → 52Hz

In this case, the fluctuation of the combustion amount is large due to the decrease of the frequency of the electromagnetic pump. However, the control based on the timing chart of FIG. 11 suppresses the rapid fluctuation of the high pressure, the suction temperature and the discharge temperature. Has been done.

The above embodiment has two outdoor units.
Although the description has been given by taking the case of connecting two indoor units as an example, the number of indoor units in the multi-room air conditioner of the present invention is not necessarily limited to two, and even when the number of indoor units is three or more. The system can be controlled by substantially the same control method based on the same idea.

[0067]

Since the present invention is constructed as described above, it has the following effects. According to the first aspect of the present invention, when the total required load from the inside of the room increases due to an increase in the number of operating indoor units during the heating operation, the compressor frequency is gradually increased to increase the refrigerant circulation amount. After a lapse of a predetermined time, the electric expansion valve corresponding to the indoor unit that receives the operation signal is controlled to open and the combustion amount of the refrigerant heater is gradually increased, so that a predetermined refrigerant circulation amount is secured. It is possible to balance the heat quantity between the heating by combustion and the heat absorption by the refrigerant circulation by increasing the combustion quantity while maintaining the relationship of the heating quantity <the heat absorption quantity (cooling quantity) due to the refrigerant circulation,
An abnormal temperature rise of the refrigerant heater can be prevented. Further, it is possible to avoid deterioration of durability due to temperature decrease of the refrigerant heater, corrosion of the inside of the heater, and occurrence of liquid back phenomenon to the compressor.

Further, by controlling the opening of the electric expansion valve corresponding to the indoor unit that receives the operation signal, the refrigerant passes through the indoor unit that receives the operation signal, and due to the influence, the amount of refrigerant circulation flowing through the refrigerant heater is instantaneous. Even if the temperature drops to 0, the relationship of the heating amount <the endothermic amount is maintained, and proper refrigerant circulation to multiple chambers is possible while ensuring the refrigerant circulation amount of the refrigerant heater.

Further, there is a possibility that the refrigerant circulation amount decreases due to the decrease in the high pressure due to the operation of the indoor fan, and the heating amount becomes larger than the refrigerant circulation amount, causing an abnormal temperature rise of the refrigerant heater. According to the invention described in 2, the indoor fan of the indoor unit that receives the operation signal is operated at the same time as the increase of the refrigerant circulation amount or after a predetermined time delay, so that the relationship of the heating amount <the heat absorption amount is secured. can do.

Further, according to the invention of claim 3 or 4, since the rate of increase of the combustion amount of the refrigerant heater is set smaller than the rate of increase of the compressor frequency, it is possible to prevent a rapid increase in the amount of heating and The heat quantity balance of the quantity <the amount of heat absorption (cooling quantity) due to the circulation of the refrigerant can be maintained.

Further, according to the invention of claim 5 or 6, since the combustion amount of the refrigerant heater is increased at the same time as or delaying the opening control of the electric expansion valve, the refrigerant is increased by increasing the number of operating units. Even if the circulation amount changes abruptly, the combustion amount can be changed to stabilize the heat amount balance between the heating by combustion and the heat absorption by the refrigerant circulation, and an abnormal temperature rise of the refrigerant heater can be prevented.

Further, according to the invention described in claim 7, the compressor frequency is set to a value equal to or larger than the value calculated by the frequency / combustion amount calculating means to increase the refrigerant circulation amount. It is possible to secure the relationship of the heating amount <the amount of heat absorption (cooling amount) due to the circulation of the refrigerant so that the temperature abnormality of the refrigerant heater is not caused even when the amount of the refrigerant circulation suddenly changes.

According to the eighth aspect of the invention, the compressor frequency is reduced to the value calculated by the frequency / combustion amount calculation means after a predetermined time has elapsed since the combustion amount of the refrigerant heater increased. From the relationship of heating amount <heat absorption amount (cooling amount) due to refrigerant circulation, it is possible to prevent the temperature of the refrigerant heater from lowering and avoid the liquid back phenomenon.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a refrigeration cycle of a multi-room air conditioner according to the present invention.

FIG. 2 is a control block diagram of a compressor frequency, a combustion amount, and an electric expansion valve opening degree in the multi-room air conditioner of FIG.

FIG. 3 is a temperature zone division diagram of a temperature difference between a room temperature and a set temperature.

FIG. 4 is a graph showing an example of a control calculation formula used for determining the compressor frequency during cooling / dry operation.

FIG. 5 is a graph showing an example of a control calculation formula used for determining a compressor frequency during heating operation.

FIG. 6 is a graph showing an example of a control calculation formula used for determining a target value of a combustion amount during heating operation.

7 is a graph showing the relationship between the target value of the combustion amount determined from the graph of FIG. 6 and the kerosene oil feed amount.

FIG. 8 is a flowchart showing control when the number of operating units changes from one-chamber operation to two-chamber operation during heating operation.

FIG. 9 is a timing chart showing control when the number of operating units changes from one-chamber operation to two-chamber operation during heating operation.

FIG. 10 is a flowchart showing control when the number of operating units changes from two-chamber operation to one-chamber operation during heating operation.

FIG. 11 is a timing chart showing control when the number of operating units changes from two-chamber operation to one-chamber operation during heating operation.

FIG. 12 is a graph showing various data when switching from one-chamber operation to two-chamber operation and the change in high pressure is large.

FIG. 13 is a graph showing various data when the combustion amount is changed from the one-chamber operation to the two-chamber operation.

FIG. 14 is a graph showing various data when the high pressure change is large after switching from the two-chamber operation to the one-chamber operation.

FIG. 15 is a graph showing various data when the two-chamber operation is switched to the one-chamber operation and the combustion amount change is large.

[Explanation of symbols]

2 outdoor unit 4a, 4b indoor unit 6 compressor 8 outdoor heat exchanger 10 four-way valve 12a, 12b Indoor heat exchanger 14 Liquid side main pipe 16a, 16b Liquid side branch pipe 18 Gas side main pipe 20a, 20b Gas side branch pipe 22a, 22b Electric expansion valve 28 Refrigerant heater 32 Electromagnetic pump 34 burner motor 36a, 36b Indoor temperature sensor 38a, 38b operation setting circuit 48 Indoor temperature detection circuit 50 Differential temperature calculation circuit 52 setting discrimination circuit 54 ON-OFF discrimination circuit 56 Rated capacity memory circuit 62 Compressor frequency / combustion amount calculation circuit 64 Expansion valve opening calculation circuit 66 Load coefficient table 70 valve initial opening table

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takahiko Ao 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-5-26530 (JP, A) JP-A-9-145130 (JP, A) JP-A-4-363555 (JP, A) JP-A-4-80562 (JP, A) JP-A-3-36449 (JP, A) JP-A-4-359763 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F24F 11/02 102 F25B 13/00 341

Claims (8)

(57) [Claims] 1. An outdoor unit having a variable capacity compressor, a four-way valve, an outdoor heat exchanger, and a refrigerant heater, and a plurality of indoor units having an indoor heat exchanger and connected in parallel. Through the gas-side branch pipe branched from the liquid-side main pipe provided in the outdoor unit and the liquid-side main pipe in which the refrigerant liquid mainly flows, and the gas-side main pipe mainly provided in the outdoor unit in which the refrigerant gas flows An electric expansion valve that can be electrically connected to control the valve opening is attached to the liquid side branch pipe, and an indoor temperature setting means for arbitrarily setting the temperature in the room where each indoor unit is installed, and an indoor temperature Indoor temperature detecting means for detecting, temperature difference calculating means for calculating the temperature difference between the temperature set by the indoor temperature setting means and the indoor temperature detected by the indoor temperature detecting means, and the rated capacity of each of the indoor units A rated capacity storage means for storing A control method at the time of changing the number of operating indoor units of a multi-room air conditioner having a frequency of a compressor and a frequency / combustion amount calculating means for calculating a target combustion amount of the refrigerant heater, the method comprising: When the total required load from the room increases due to the increase in the number of operating machines, the compressor frequency is gradually increased to increase the refrigerant circulation amount, and after a certain period of time, the above-mentioned electric motor corresponding to the indoor unit receiving the operation signal is received. A control method for changing the number of operating indoor units of a multi-room air conditioner, wherein the expansion valve is controlled to be opened and the combustion amount of the refrigerant heater is gradually increased. 2. The indoor unit for a multi-room air conditioner according to claim 1, wherein the indoor fan of the indoor unit that receives the operation signal is operated at the same time as the refrigerant circulation amount is increased or after a delay of a predetermined time. Control method when the number of operating vehicles changes. 3. The control when changing the number of operating indoor units of the multi-room air conditioner according to claim 1 or 2, wherein the increasing rate of the combustion amount of the refrigerant heater is set smaller than the increasing rate of the compressor frequency. Method. 4. The multi-room air conditioner according to claim 1, wherein the combustion amount of the refrigerant heater is increased stepwise, and the average increase rate is set smaller than the increase rate of the compressor frequency. Control method when the number of operating indoor units changes. 5. The opening control of the electric expansion valve and the increase of the combustion amount of the refrigerant heater are performed at the same time.
2. A control method for changing the number of operating indoor units of the multi-room air conditioner according to any one of 1. 6. The combustion amount of the refrigerant heater is increased after a delay from the opening control of the electric expansion valve.
5. A control method when the number of operating indoor units of the multi-room air conditioner according to any one of 4 to 4 changes. 7. The refrigerant circulation amount is increased by setting the compressor frequency to a value equal to or greater than a value calculated by the frequency / combustion amount calculating means. The control method for changing the number of operating indoor units of the multi-room air conditioner described in. 8. The compressor frequency is reduced to a value calculated by the frequency / combustion amount calculation means after a predetermined time has elapsed from the increase in the combustion amount of the refrigerant heater.
2. A control method for changing the number of operating indoor units of the multi-room air conditioner according to any one of 1.