JPH06137645A - Control method of air-conditioning system - Google Patents

Abstract

PURPOSE:To reduce the operating sets of air-conditioning machines and effect the feedback control of water temperature smoothly by a method wherein reducing and/or increasing control zones, set respectively so as to reduce and/or increase the operating sets of air-conditioning machines by the minimum number of units of control, are set in accordance with respective temperature changes. CONSTITUTION:An offset (y) is operated by a subtractor 22 based on the objective control data S of an objective temperature setting circuit 21 and the detecting temperature Da of a water temperature detector Sw. When the offset (y) is in a maximum number control zone (N=total number) which has exceeded the muximum setting limit line (yn) of an insufficient control value, the operating sets N of a center unit is set so as to be N. As a result, the insufficient control value is reduced and the offset (y) becomes the muximum number setting limit line (yn), then, the offset (y) is brought into an insufficient control zone and the number N of operating sets is retained. Thereafter, the stationary difference is shifted into a reducing control zone and the number B of operating sets is reduced at every detections of water temperature. As a result, the reducing control zone (N=-1), an increasing control zone (N=+1) and no-change control zone (N=0) are provided across a plurality of inclined lines (b1), (b2).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling an air conditioning system comprising a center heat pump unit having water circuits connected to each other and an indoor water heat source heat pump unit.

[0002]

2. Description of the Related Art Conventionally, as an air conditioning system of this type, FIG.
Those shown in are known.

In the figure, HC1, HC2, ... Are center units composed of center heat pump units having the same structure, and AC1, AC2, .. are indoor units composed of water heat source heat pump units having the same structure. , WA is a forward water circuit between the center units HC1, HC2, ... And the indoor units AC1, AC2, ..., WB is a return water circuit, and P is a circulation pump.

In the center units HC1, HC2, ..., the first refrigerant flow port 1a of the four-way valve 1 is on the discharge side of the compressor 2, and the second refrigerant flow port 1b is of the compressor 2 via the accumulator 3. On the suction side, the third refrigerant circulation port 1c is on one end of the outdoor air heat exchanger (hereinafter referred to as air heat exchanger) 4, and the fourth refrigerant circulation port 1d is on the indoor side water heat exchanger (hereinafter referred to as water). A heat exchanger 5) is connected to one end of the heat exchanger 5, and an expansion valve 6 is provided between the heat exchangers 4 and 5.

In the indoor units AC1, AC2, ..., The first refrigerant flow port 7a of the four-way valve 7 is on the discharge side of the compressor 8, and the second refrigerant flow port 7b is via the accumulator 9. The third refrigerant circulation port 7c is provided at one end of the outdoor water heat exchanger (hereinafter referred to as water heat exchanger) 10, and the fourth refrigerant circulation port 7d is provided at the indoor side air heat exchanger (hereinafter, referred to as An expansion valve 12 is provided at one end of an air heat exchanger 11) and between the other ends of the heat exchangers 10 and 11. Reference numeral 13 is a fan that circulates the air in the room by ventilating the air heat exchanger 11. SR is an indoor temperature detector that detects the indoor temperature of the air heat exchanger 11 of each indoor unit AC1, AC2, ..., And 14 is a terminal control unit that controls each indoor temperature. The terminal control unit 14 controls the operation of the fan 13 and the like, and refers to the detected indoor temperature to control the operation of the compressor 8 so that the indoor temperature of the indoor unit approaches a designated control target value. Dodge control.

The outlet 5a of the water heat exchanger 5 of each center unit HC1, HC2, ... And each indoor unit AC1, AC2
, Are connected to the inlet 10a of the water heat exchanger 10 via a common water circuit WA, and the inlet 5b of the water heat exchanger 5 is connected.
And the outlet 10b of the water heat exchanger 10 are connected via a common water circuit WB.

SW is a water temperature detector for detecting the water temperature of the water circuit WA at the center units HC1, HC2, ...
The water temperature is detected at predetermined time intervals. Reference numeral 15 is a centralized control circuit for controlling the water temperature of the water circuit WA, which is a steady-state deviation y = S-Da due to the difference between the set temperature S of the water temperature and the detected water temperature Da.
, And the detected water temperature Da is adjusted by adjusting the number of operating center units HC1, HC2, ... Based on the temperature variation x = Db−Da which is the difference between the previously detected water temperature Db and the detected water temperature Da this time. Feedback control is performed so as to approach the target value in the temperature range.

When performing the cooling operation in this air conditioning system, the refrigerant in each of the compressors 2 and 8 circulates as shown by the solid arrows in the figure, and the water heat exchanger 5 in the center units HC1, HC2, ... Water is cooled and indoor units AC1, AC2
The water in the water heat exchanger 10 is heated. Further, when performing the heating operation, the refrigerant in each of the compressors 2 and 8 circulates as indicated by the one-dot chain line arrow in the figure, the water in the water heat exchanger 5 is heated, and the water in the water heat exchanger 10 is heated. The water is cooled. In the air conditioning operation, the water in the water heat exchangers 5 and 10 circulate with each other by the circulation pump P as indicated by the broken line arrow in the figure. The temperature of the water circuit WA is the detected water temperature D of the water temperature detector Sw.
Center unit HC so that a is within the specified temperature range.
The number N of 1, HC2, ... Is controlled and water in a predetermined temperature range flows into the water heat exchanger 10. In each of the indoor units AC1, AC2, ..., The compressor 8 is controlled so that the detected temperature of each indoor temperature detector SR becomes the specified temperature, and the air conditioner is conditioned to the specified indoor unit indoor temperature. To be done.

FIG. 3 is an operation condition setting diagram showing the relationship between the state of the water temperature based on the detected temperature (detected water temperature) of the water temperature detector Sw and the number of operating center units HC1, HC2, ... In the cooling operation.

In the figure, the horizontal axis represents the above temperature variation x
= Db-Da, and the vertical axis represents the steady-state deviation y = S-Da. The set temperature S of the water temperature is, for example, 25 ° C., and in the case of the cooling operation, when y is an insufficient control value of −4 ° C. or less, all the units operation (N = total number) is designated, and y is an excessive control of 0 ° C. or more. When it is a value, all units are stopped (N = 0), x is 0 ° C or less, and y
Is -1.5 to -4 ° C or x is -0.5 ° C or less and y is 0.
In the case of ~ -1.5 ° C, +1 unit (N = + 1) is designated and x
Is 0.5 ° C or higher and y is 0 to -4 ° C, -1 unit (N =
-1) Designated, and in other cases, ± 0 units (N = ± 0) are designated.

[0011]

However, in the above-mentioned air conditioning system, the number of operating units N depends on the water temperature condition.
Shifts as indicated by the arrow in FIG. 3, but N = ± as shown in FIG. 3 in order to reduce the frequency of start / stop due to the change of N.
In the 0-unit designated area, x is in a predetermined small value range (0 to 0.
6 ° C.) and y is set in the region between each boundary line between N = total designation and N = 0 designation (−4 ° C. and 0 ° C.), so N = ± 0 to N = Specify all numbers or N = 0
When y changes to move to the designated state, there is a problem that the number of starting and stopping at that time increases and the change in water temperature becomes large.

It is an object of the present invention to provide a control method for an air conditioning system in which the change in the number of operating center units is reduced and the water temperature is smoothly feedback controlled.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a plurality of center units, each of which is a center heat pump unit for adjusting the temperature of a water circuit, and a water heat unit connected to the water circuit. An indoor unit that has a water heat source heat pump unit to be replaced, a circulation pump that circulates water in the water circuit between the center unit and the indoor unit, and a water temperature detector that detects the water temperature of the water circuit at predetermined time intervals. Based on the steady-state deviation that is the difference between the set water temperature and the detected water temperature, and the amount of temperature change that is the difference between the previously detected water temperature and the currently detected water temperature, the number of operating center units is adjusted In a control method of an air conditioning system for feedback controlling the temperature of a circuit, the characteristics of the control are:
A minimum number setting limit line that is substantially constant with respect to the temperature change amount due to a small value of the steady-state deviation, and a maximum number setting limit line that is substantially constant with respect to the temperature change amount due to the insufficient control value of the steady-state deviation. And a slope line limited to a region between the minimum number setting limit line and the maximum number setting limit line, and a sum of a proportional value with the temperature change amount and the steady deviation is first.
A first sloped line consisting of a constant and a second sloped line consisting of a second constant whose sum is greater than the first constant, each sloped line being defined by the change of the steady-state deviation. It has an intersection with a water temperature stability line where the amount of temperature change is almost 0, and the steady-state deviation is in a region of an excessive control value that exceeds the minimum number setting limit line, and the operating number is set to a predetermined minimum number. The set minimum number control area, the shortage control value area that exceeds the maximum number setting limit line and sets the operating number to a predetermined maximum number, and the sum value is the first constant. Is a smaller area than the above, and is an increase control area set to increase the number of operating vehicles by the minimum number of units for control, and an area in which the value of the sum is larger than the second constant A reduction control region set to decrease by the number of units, and the sum value is the first constant and the second constant. A region value between provided and invariant control area set the number of operating without increase or decrease.

[0014]

According to the present invention, based on the detected water temperature, when the steady deviation exceeds the maximum number setting limit line due to the insufficient control value at the time of start-up, etc. Is set to. As a result, when the shortage control value decreases and the steady-state deviation falls within the maximum number setting limit line, the temperature change amount is in the invariable control region because it is due to the forward control, and the operating number is maintained. In the process in which the steady-state deviation goes from the maximum number control region side to the minimum number control region side, the temperature change amount is due to the forward control, and therefore the invariant control region does not shift to the minimum number control region. Subsequently, in the process, the number of operating vehicles is reduced every time the water temperature is detected by shifting to the decrease control region, and the alternate control region is alternately moved to the decrease control region and the constant control region across the second slope line,
Alternatively, it is controlled in the vicinity of the steady state deviation 0 while alternately moving to the increase control region and the invariant control region across the first slope line. When the steady deviation exceeds the minimum number setting limit line during the control and the steady deviation exceeds the minimum number setting limit line, the operation shifts to the minimum number control region and the operating number becomes the minimum number. After that, when insufficient control is performed and the steady deviation exceeds the minimum number setting limit line, the temperature change amount at this time is due to reverse direction control, and therefore the temperature is in the invariable control region, and the stopped state is maintained. In the process of steady deviation from the minimum number control region side to the maximum number control region side in the stopped state, the temperature change amount is due to the reverse direction control, so there is no transition from the constant control region to the maximum number control region. . After that, the same control as described above is performed. When the control becomes insufficient during the control and the steady deviation exceeds the maximum number setting limit line, the maximum number control region is entered and the number of operating vehicles becomes the maximum number.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an operating condition setting diagram showing the relationship between the water temperature state of an air conditioning system and the number of operating center units as an embodiment of the present invention. FIG. 4 is an air conditioning system showing an example of the configuration of the present invention. It is a block diagram of a control circuit. FIG. 1 shows an example of the cooling operation as in FIG. 3, and the control circuit of FIG. 4 is used in place of the centralized control circuit 15 of FIG. 2 and is a main part of the control circuit for the center unit. Shows the configuration of.

In FIG. 4, reference numeral 20 denotes an operating condition setting circuit, which operates the number N of the center units according to the designation of the number of combinations of the temperature variation x and the steady-state deviation y shown in FIG.
To set. Reference numeral 21 is a target temperature setting circuit, which outputs control target data S of the water temperature based on a desired temperature designation. Two
Reference numeral 2 is a subtracter, which subtracts the temperature (detected water temperature) Da detected at this time by the water temperature detector Sw from the control target data S to obtain a steady-state deviation y.
= S-Da is output. 23 is a temperature change amount calculation circuit,
The detected water temperature Da of this time is subtracted from the previously detected water temperature Db to output a proportional value ax = a (Db-Da) of the temperature change amount (where a is a constant and is 1 in FIG. 4). Reference numeral 24 is a steady-state deviation discriminating circuit, in which when the steady-state deviation y exceeds the maximum number setting limit line y = yU which makes the limit value yU due to insufficient control, the operating number N = total number is specified and the limit value yL due to excess control is set. When the minimum number setting limit line y = yL is exceeded, the operating number N = 0 is designated, and when it is within the range of each limit line, the steady deviation y is output. 25 is the first and second of FIG.
In the adder relating to the inclination setting of the inclination line, the proportional value ax of the temperature change amount and the steady deviation y are added to output ax + y. 26 is the first inclined line ax + y = b1 and the second inclined line ax + y = b1
And set the slope line ax + y = b2 of
Each comparison reference value (constant) b
1 and b2, N = + 1 when ax + y≤b1
, N = −1 when ax + y ≧ b2, and b1 <
When ax + y <b2, N = ± 0 is output. The constants b1 and b2 are set such that the second constant b2 is larger than the first constant b1, and the first and second sloped lines show the temperature variation x with respect to the change of the steady deviation y. The constants a, b1 and b2 are set together with the constant a so that the intersection with the water temperature stability line SM, which is almost 0, is located near the limit lines between the limit lines y = yU and y = yL. ing. Reference numeral 27 is an operating number setting circuit, which receives the outputs of the steady deviation discriminating circuit 24 and the comparing circuit 26 and sets the operating number of the center unit. 28 is a compressor drive circuit, which operates each compressor 2 of the center unit according to the setting of the operating number setting circuit 27. In the heating operation, the signs of the numbers at each coordinate in FIG. 1 are reversed.

Next, the operation of the above configuration will be described by taking the cooling operation as an example. Control target data by the target temperature setting circuit 21
Temperature S and water temperature detector Sw detection temperature (detection water temperature) D
On the basis of a, the steady-state deviation y = S−Da by the subtractor 22.
Is calculated, and when the steady deviation y is in the maximum number control region (N = total number) of −4 ° C. or less that exceeds the maximum number setting limit line y = yU due to the insufficient control value at the time of start-up, etc. The operating number N is set to the total number. As a result, when the insufficient control value decreases and the steady-state deviation y = S-Da falls within the maximum number setting limit line y = yU due to the insufficient control value, the temperature change amount x is due to the forward control at this time. As shown by the arrow in FIG. 1, the control range becomes invariable (N is ± 0), and the operating number N is held. In the process in which the steady-state deviation y moves from the maximum number control region (N = total number) side to the minimum number control region (N = 0) side, the temperature change amount x is due to the forward control of the water temperature variable operation, and therefore it does not change. Control area (N is ±
There is no transition from 0) to the minimum number control area (N = 0). In the subsequent process, the decrease control region (N
By shifting to 1), the operating number N is reduced each time the water temperature is detected.
As a result, it crosses the second slope line ax + y = b2 and alternately moves to the decrease control region (N to -1) and the invariant control region (N = 0), or crosses the first slope line ax + y = b1. While moving alternately to the increase control region (N is +1) and the invariant control region (N = 0), the control is performed in the vicinity of the steady deviation y = 0. When the steady deviation y exceeds the minimum number setting limit line y = yL during the control and the steady deviation y exceeds the minimum number setting limit line y = yL, the minimum number control region (N = 0) is entered and the operating number N becomes zero. afterwards,
Insufficient control causes steady-state deviation y to be the minimum number setting limit line y = y
When L is exceeded, the temperature change amount x at this time is due to the reverse control of the water temperature variable operation, so that it is in the invariable control region (N is ± 0) and the stopped state is maintained. In the process of the steady deviation y from the minimum number control region (N = 0) side to the maximum number control region (N = total number) side in the stopped state, the temperature change amount x is due to the backward control, and thus the invariant control is performed. There is no transition from the region (N is ± 0) to the maximum number control region (N = total number) side. After that, the same control as described above is performed.
When the control becomes insufficient during the control and the steady deviation y exceeds the maximum number setting limit line y = yU, the maximum number control region (N = N
(The total number) and the number of operating units N becomes the maximum number.

[0018]

As described above, according to the present invention, when the number of operating center units shifts from the maximum number operation designation to the minimum number operation designation, the number of operating units should be reduced by the minimum number of control units. By intervening the set decrease control area in correspondence with the temperature change of the detected water temperature that may occur in that case, when shifting from the minimum number operation specification to the maximum number operation specification, the number of operating units is increased by the minimum unit number of control. By similarly interposing the increase control region set as necessary, the change in the number of operating center units is reduced, and the water temperature is smoothly feedback-controlled.

[Brief description of drawings]

FIG. 1 is an operation condition setting diagram showing the relationship between the water temperature state of an air conditioning system and the number of operating center units as an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional air conditioning system

FIG. 3 is an operating condition setting diagram showing the relationship between the water temperature state of the conventional air conditioning system and the number of operating center units.

FIG. 4 is a block diagram of a control circuit of an air conditioning system showing a configuration example of the present invention.

[Explanation of symbols] HC1, HC2 ... Center unit, AC1, AC2 ... Indoor unit, SW ... Water temperature detector, WA, WB ... Water circuit,
2 ... Compressor, 20 ... Operating condition setting circuit, 21 ... 21 ... Target temperature setting circuit, 22 ... Subtractor, 23 ... Temperature change amount calculating circuit, 24 ... Steady state deviation discriminating circuit, 25 ... Adder, 26 ...
Comparison circuit, 27 ... Operating number setting circuit, x ... Temperature change amount, y ... Steady deviation, y = yU ... Maximum number setting limit line, y =
yL ... Minimum number setting limit line, ax + y = b1 ... First inclined line, ax + y = b2 ... Second inclined line.

Claims (1)

[Claims] 1. A plurality of center units having a center heat pump unit for adjusting the temperature of a water circuit, an indoor unit having a water heat source heat pump unit connected to the water circuit for exchanging water heat, and a center. A circulation pump that circulates water in the water circuit between the unit and the indoor unit and a water temperature detector that detects the water temperature of the water circuit at predetermined time intervals are provided, and the difference between the set temperature of the water temperature and the detected water temperature is provided. In the control method of the air conditioning system, which controls the temperature of the water circuit by controlling the number of operating center units based on the steady-state deviation and the amount of temperature change consisting of the difference between the previously detected water temperature and the currently detected water temperature, Is almost constant with respect to the temperature change amount and is substantially constant with respect to the temperature change amount and the minimum number setting limit line due to the small value of the steady deviation. Therefore, the maximum number setting limit line due to the insufficient control value of the steady deviation, and each slope line limited to the region between the minimum number setting limit line and the maximum number setting limit line A first sloped line in which the sum of the proportional value and the steady-state deviation is a first constant and a second sloped line in which each sum is a second constant greater than the first constant is defined. The slope line has an intersection with the water temperature stability line where the temperature change amount is almost 0 with respect to the change of the steady deviation, and the steady deviation of the excess control value exceeds the minimum number setting limit line. A minimum number control area in which the number of operating vehicles is set to a predetermined minimum number, and a maximum number control in which the number of operating vehicles is set to a predetermined maximum number in the area of the insufficient control value that exceeds the maximum number setting limit line. Area and the area where the sum value is smaller than the first constant and the operating unit is the minimum unit of control An increase control region set to increase only the above, a decrease control region set to decrease the number of operating vehicles by the minimum unit number of control when the value of the sum is larger than the second constant, Value is first
A control method for an air conditioning system, characterized in that an invariant control area in which the number of operating vehicles is set without increase or decrease is provided, which is an area of a value between the constant and the second constant.