JPH04103946A - Multi-room air conditioner - Google Patents

Abstract

PURPOSE:To realize a room temperature control and a proper control of a heat pump cycle in a simple way by a method wherein temperature detectors for respective rooms and an overheat degree detecting means of a refrigerant at an outlet of a vaporizer are provided, and capacities of a plurality of room expansion valves and compressors are controlled so as to make the respective room temperatures coincide with respective set room temperatures. CONSTITUTION:A compressor 2 which is variable in the capacity, temperature detectors 7A, 7B and 7C for respective rooms and an overheat degree detecting means 10 are provided. If standard load capacities of respective indoor units 4A, 4B and 4C are represented by Ci (i=1, 2...: corresponding to the respective indoor units), differences between respective set room temperatures and respective room temperatures are represented by Di (i=1, 2...), the compressor 2 is operated by a value Uc (a capacity command of the compressor 2) which is obtained from expressions (1) and (2) by using a control operation functions fj (j=1, 2...) and an additional operator SIGMA. When an error of a detected overheat degree with respect to a target overheat degree is represented by ESH, opening degrees Ui (i=1, 2...) of expansion valves 6A, 6B and 6C for the respective rooms are set by expressions (3), (4) and (5). Further, if differences between an outdoor temperature and set room temperatures of the respective rooms are represented by Ti (i=1, 2...), the openings (degrees Ui of the expansion valves of the respective rooms are set by an expression (11), with USHO as a constant value and Ki as a coefficient.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention is a multi-room type device that includes one outdoor unit and a plurality of indoor units connected in parallel to the outdoor unit, and controls room temperature and heat pump cycle. Conventional technology related to air conditioners General paper A multi-room air conditioner is configured as shown in Figure 3.The configuration will be explained below.The outdoor unit 1 is connected to the compressor 2 and Outdoor heat exchanger 3
Indoor unit 4A, 4&4Ci indoor heat exchanger 5A, 5&5Ci indoor expansion valve 6A, 6B,
6C, and room temperature detectors 7A, 7 & 7C.Outdoor unit 1 and each indoor unit 4A.

The gas side and liquid side of 4 & 4C are connected by gas side pipe 8 and liquid side pipe 9 respectively to form a closed circuit. Even if refrigerant is sealed inside the closed circuit to form a heat pump cycle, compressor suction The pressure detector 10 and the compressor suction temperature detector 11 form a superheat degree detection means, which calculates the degree of superheat of the compressor suction portion. The outside air temperature detector 12 detects the outside air temperature and calculates the difference from the set temperature of each room to calculate the heat load of each room. In the above configuration,
The outdoor heat exchanger 3 works as a condenser, and each indoor heat exchanger 5
A, 5 & 5C act as evaporators and cool each room by absorbing heat from the air in each room. At this time, if the opening degree of each indoor expansion valve 6A, 6B, 6C is increased,
Even if the flow rate of the refrigerant increases, the cooling capacity increases, and the temperature in each room decreases, the temperature will be reflected by each room temperature detector 7A, 7 & 7.
By switching the input and output of compressor 2 using a four-way valve (not shown), the direction of refrigerant flow is reversed, and indoor heat exchangers 8A, 5 & 5C are The condenser is the condenser, and the outdoor heat exchanger 3 is the evaporator. Conventionally, the method of controlling each indoor expansion valve of such a multi-room air conditioner is the so-called PID control method, or the operation amount is determined according to the conditions. Even if a table search method is adopted, in these controls (the control means is realized by a microcomputer, etc., and the means itself is not shown), the PID control method obtains error information with respect to the target value, integrates it into a ratio of the error information, The manipulated variable was determined by calculating the differential and adding the calculated result to the controlled object at an appropriate ratio. However, the method of setting the control operation amount (such as the expansion valve opening degree and compression function of each chamber) can solve the problems that the invention was trying to solve.
There is interference between each room, and it is necessary to control the temperature according to the set temperature.
Arc control for high efficiency heat pump cycle operation
For example, controlling the degree of superheating at the same time was complicated and difficult.The present invention solves the above problems, and the first step is to realize room temperature control and appropriate control of the heat pump cycle in a simple manner. In order to achieve the above first objective, the present invention (above) is a means for solving the problems, even if the second objective is to improve the coordination by adding feedforward control. A variable compressor, a room temperature detector, and a superheat degree detection means are CL.
The standard load capacity of each indoor unit is Ci (i=1.2...
・, :corresponds to the indoor unit), and the difference between the set temperature of each room and the temperature of each room is Di(i-IJ...), and the capacity command Uc of the compressor is expressed as the control calculation function fj()(j= 1, 2,...
), using the addition operator Σ, the following dog E=Σ (Ci×
Di) ・ ・ ・(1) Uc= fl
(E) ・ ・The compressor is operated according to the value Uc obtained in (2), and the error between the detected degree of superheat and the target degree of superheat is set as ESH, and the opening degree of the expansion valve of each chamber [J i (1-L2 .3,...) as follows, USH= f 2 (ESH) + USHO...(3
) [) av=E/ΣCi ---(4) Ui
=USH+f 3 (Di-Dav) ・ ・ ・(
In order to achieve the second objective, we will use the settings set in 5) as the first means of solving the problem.In order to achieve the second objective, we will have a compressor with variable capacity, a room temperature detector, a superheat detection means, and an outside temperature detector. The standard load capacity of each indoor unit is Ci (i=1, 2,
), the difference between each room set temperature and each room temperature is Di (i=
1.2...), the difference between the outside air temperature and the set temperature of each room is 'f i (i=1, 2,...), the capacity command Uc of the compressor is set, and Ai is a constant. Using the control calculation function f j () (j = 1, 2, ...), the following dog E = Σ (Ci × Di) ... (7
) Uc= f l (E) +Σ (Aix Cix
Ti)...Operate the compressor using the value Uc obtained in (8), take the error of the detected degree of superheat to the target degree of superheat as ESH, and use USHO as a constant mKi as a coefficient to open the expansion valve of each chamber. Degree Ui (i-L2.3,・
), the following civil USH = f 2 (ESH) +
USHO...(9) Dav=E/ΣCi
...(10) Ui=USH+f3(D
i-Dav), +KixCiXTi...(11) The present invention also works even if the settings are set as the second problem-solving means.
is the addition of the room temperature error with respect to the set temperature, weighted by the heat capacity of the indoor unit, and a control system that follows the target value is constructed using the control calculation function of equation (2).Equations (3) and (4)
indicates that the degree of superheat is controlled using the average value of the expansion valve opening of each chamber.The distribution of refrigerant to each chamber is performed using the deviation from the average value of the expansion valve opening. In other words, refrigerant distribution control is the control of the distribution ratio, and there is no need to control the absolute amount of valve opening.Since there is one remaining manipulated variable, it is possible to control the degree of superheat, which is the state quantity of the heat pump cycle. By the second problem-solving means, the second term G of equation (8)
L is a term that converts the total heat load into compressor work, and is a feedforward control amount that provides a manipulated variable corresponding to the required amount of heat in advance, and can improve coordination and steady-state characteristics. One embodiment will be explained with reference to FIGS. 1 and 2.A. The entire system is the same as that shown in FIG. 3, and the explanation will be omitted. This is a block diagram of the control system for controlling the opening degrees of 6 & 6c, and superheat degree information (upper
It is compared with the target degree of superheating, and the error is manually input to the PID controller 13 and calculated as %.
1. PID computation is performed to control the degree of superheating. The output of the PID controller 13 is sent to adders 14 and 15 for controlling the expansion valves in each chamber. Also, error information between the set temperature and the detected room temperature is sent. Di information is standard load capacity 16,
17, an adder 18, and a divider 19, the load of error information with respect to the room temperature is converted into weighted average information Dav. Compared to the room temperature error, therefore,
The outputs of the comparators 20 and 21 correspond to the difference between the room temperature error Di and the average value.The outputs of the comparators 20 and 21 are sent to the PID controllers 22 and 23, which control the expansion valves to adjust the room temperature to the set value. Even when control calculations are performed, the outputs of the PID controllers 22 and 23 are sent to the adders 14 and 15. The result of adding the expansion valve opening command information is added to the actual indoor expansion valve 6A,
The command is sent to the expansion valve opening control means (not shown) in each chamber as the opening command for the expansion valves 6A and 6C.
Fig. 2 is a block diagram of the control system for controlling the capacity of compressor 2. Items using the same calculations as in Fig. 1 are indicated by the same symbols. Di is input to the adder 18 through the standard load capacity 16 and 17 of each room. The product-sum calculation result is determined and the result is input to the PID controller 24.The PID controller 24 performs PID calculation to control the capacity of the compressor 2 so that the room temperature reaches the set temperature. The calculation result is sent to the inverter 25 and converted into rotation speed information of the compressor 2.The operating state of the control system shown in Fig. 2 can be summarized as follows: The degree of superheating of the heat pump cycle is controlled using the average information of the opening degrees of 6 & 6C, and the heat distribution is controlled by giving the deviation from the average value of the expansion valve opening degree of each chamber using the room temperature error information.The same applies to compressor control. A feedback control system for the total average heat quantity is constructed based on room temperature error information.
For example, the present invention can be applied to a method using the difference between the temperature at the outlet of the indoor expansion valve and the temperature at the outlet of the evaporator), and does not go beyond the scope of the present invention. The standard heat load is used to predict the load of 4C. A force that does not necessarily match the heat load of the actual installation (error ζ due to the mismatch) is detected as an error in room temperature and can be resolved by feedback control. This should not be a problem since it is possible to
This will be explained with reference to the figures.Those having the same configuration as those in the above embodiment will be given the same reference numerals and the explanation will be omitted. In the block diagram, the outputs of PID controllers 22 and 23 are sent to adders 14 and 15, and the deviation information Ti between the outside air temperature and the set temperature is input to standard load capacities 26 and 27. Then, multiply the standard load factor of the installed indoor units 4A, 14B, and 4C and send the result to blocks 28 and 29 as the required amount of heat.Blocks 28 and 29 calculate how much the refrigerant flow rate should be increased in response to the amount of heat. The outputs of blocks 28 and 29 are sent to adders 14 and 15; Add the expansion valve opening command information from the superheat degree error information, the expansion valve opening command information from the temperature error information, and the expansion valve opening command information from the thermal load information. The opening command is sent to the expansion valve opening control means (not shown) in each chamber to control the opening of the expansion valve in each chamber. In the block diagram, the calculation results of the PID controller 24 are sent to the adder 30, and the deviation information between the outside air temperature and the set temperature of each unit is obtained through the standard load capacities 31 and 32 of each room to obtain the required heat amount information. After that, the output of the adder 35 is sent to the adder 30, and the output of the adder 30 is sent to the inverter 25, and the output of the adder 30 is sent to the To summarize the operating status of the control system shown in Figure 5, the degree of superheating of the heat pump cycle is controlled using the average information of the opening degrees of the expansion valves of each chamber. The heat distribution is controlled by giving the deviation from the average value of the expansion valve opening of each room using the room temperature error information.Furthermore, the amount of heat at steady state can be given as a feedforward control amount based on the difference between the outside temperature and the set temperature. The same applies to machine control. A feedback control system for the total average heat amount is configured based on the room temperature error information, and the heat amount at steady state is given as a feedforward control amount based on the difference between the outside temperature and the set temperature. In the embodiment, the force explained using PID control as a feedback control calculation method (even a method using modern control theory does not exceed the content of the present invention).
In addition, it goes without saying that the force t explained in the case of a multi-room air conditioner is effective even when there is only one indoor unit. The standard load capacity of the machine is Ci (i=1.2...,:
Compatible with indoor units), the difference between each room temperature setting and each room temperature 1)
i (i=1.2...), the capacity command Uc of the compressor is controlled by a calculation function f j □ (j-L2,...
), using the addition operator Σ, the following person E = Σ (Ci × Di) ... (1) Uc =
f 1 (E) ... The compressor is operated according to the value Uc obtained in (2), and the error between the detected degree of superheat and the target degree of superheat is set as ESH, and the opening degree Ui (i = 1, 2, 3, ...) as the following civil USH = f 2 (ES)l) + USHO・・(
3) Dav=E/ΣCi・
・ ・(4) Ui=USH+f3(Di-Dav
) ・ ・ ・The settings in (5) can be used to achieve proper room temperature control and heat pump cycle control in a simple way. Ti (i=1.2
．． ), the capacity command Uc of the compressor is expressed as A
Let i be a constant and control calculation function fjO(j-L2,...
), the compressor is operated according to the value Uc obtained from the following equation 8 (7) using the addition operator Σ, and the error in the detected degree of superheat relative to the target degree of superheat is taken as ES)I,
Using USHO as a constant tKi, the opening degree U 1 (1=1, 2, 3, ...) of the indoor expansion valve of each chamber is determined by the following length USH = f 2 (ESH) + USHO... (
9)])av=E/ΣCi...(1
0) Ui = USH ten f 3 (Di-Di) + KixC
ixTi...(11) Feedforward control can be added to improve coordination.

[Brief explanation of drawings]

Figure 1 is a block diagram of the control system for the indoor expansion valve of a multi-chamber air conditioner according to an embodiment of the present invention. Figure 2 is a block diagram of the control system of the compressor of the multi-chamber air conditioner. 4 is a block diagram of the control system of the indoor expansion valve of a multi-chamber air conditioner according to another embodiment of the present invention. FIG. This is a block diagram of the control system of the compressor of the machine.Outdoor A 2...Compression A 3...Outdoor heat exchanger 4A, 4 & 4C...Indoor air 5A, 5 & 5
C... Indoor heat exchanger 6A, 6&6C... Indoor expansion valve, 7A, 7&7C... Room temperature detection Bto... Compressor suction pressure detector (superheat degree detection means), 11... Compressor suction Temperature detector (superheat detection means). Name of agent: Patent attorney Shigetaka Awano (1 person)

Claims (5)

[Claims] (1) One outdoor unit consisting of a variable capacity compressor and an outdoor heat exchanger, a plurality of indoor units each including an indoor heat exchanger and an indoor expansion valve and connected in parallel to the outdoor unit; Each indoor unit is equipped with a room temperature detector that detects the room temperature of each room installed, and a degree of superheat detection means that detects the average degree of superheat of the refrigerant at the outlet of the evaporator, so that the room temperature of each room matches the set temperature of each room. A multi-room air conditioner that controls the plurality of indoor expansion valves and compression function, wherein the standard load capacity of each indoor unit is C.
i (i=1, 2, . . . :corresponds to the indoor unit), and the difference between the set temperature of each room and the temperature of each room is Di (i=1, 2, . . .), and the capacity command of the compressor is Uc is the control calculation function fj(
) (j=1, 2,...), using the addition operator Σ, the following formula E=▲There are mathematical formulas, chemical formulas, tables, etc.▼...(1
) Uc=f1(E)...(2) The compressor is operated according to the value Uc obtained from Degree Ui (i=1, 2, 3,...)
The following formula USH=f2(ESH)+USHO...(3)Dav
=▲There are mathematical formulas, chemical formulas, tables, etc.▼...(4) Ui=USH+f3(Di-Dav)...(5) A multi-room air conditioner. (2) Instead of the opening degree Ui of the expansion valve of each chamber in equation (5), U
i=USH+f4(Ci×Di-Dav)...(6)
The multi-room air conditioner according to claim 1, wherein the multi-room air conditioner is set as follows. (3) one outdoor unit consisting of a variable-capacity compressor and an outdoor heat exchanger, a plurality of indoor units each including an indoor heat exchanger and an indoor expansion valve and connected in parallel to the outdoor unit; Each indoor unit is equipped with a room temperature detector for detecting each room temperature, an outside temperature detector for detecting the temperature of the outside air, and a degree of superheat detection means for detecting the average degree of superheat of the refrigerant at the outlet of the evaporator. A multi-room air conditioner that controls the plurality of indoor expansion valves and compression function so that the room temperature matches the set room temperature, wherein the standard load capacity of each indoor unit is set to Ci (i=1, 2 ,
), the difference between each room set temperature and each room temperature is Di (i=
1, 2...), the difference between the outside air temperature and the set temperature of each room is Ti (i = 1, 2,...), and the capacity command Uc of the compressor is controlled with Ai as a constant. Arithmetic function fj()
(j=1, 2,...), using the addition operator Σ, the following formula E=▲There are mathematical formulas, chemical formulas, tables, etc.▼...(7) Uc=▲There are mathematical formulas, chemical formulas, tables, etc. ▼... (8) Operate the compressor with the value Uc obtained, and let the error of the detected degree of superheat against the target degree of superheat be ESH, and calculate the US
With HO as a constant value and Ki as a coefficient, the opening degree Ui (i=1, 2, 3,...) of the indoor expansion valve of each chamber is calculated using the following formula, U
SH=f2(ESH)+USHO...(9)Dav=
▲There are mathematical formulas, chemical formulas, tables, etc.▼...(10) Ui=USH+f3(Di-Di)+Ki×Ci×Ti
...(11) A multi-room air conditioner configured as follows. (4) Replace the opening degree Ui of the indoor expansion valve of each chamber with equation (11), Ui=USH+f4(Ci×Di-Dav)...(1
4. The multi-room air conditioner according to claim 3, wherein the multi-room air conditioner is configured in accordance with 2). (5) The control calculation function fj() is a linear sum of the results of at least two calculations among a proportional calculation, a first-order or higher differential calculation, and a first-order or higher integral calculation. multi-room air conditioner.