JPH0563693B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an air conditioner that employs a variable air volume control system that can independently adjust the room temperature of each room.

[Conventional technology]

Central air conditioning systems, which use air ducts to distribute temperature-controlled air to each room for air conditioning, can easily incorporate humidifiers and high-performance filters, and can also use outside air processing and total heat exchangers. The heat pump chiller/fan coil system and packaged air conditioner distributed arrangement system can achieve high air conditioning, and since the room to be air conditioned has only an air outlet and an inlet, indoor space can be used effectively, and there are fewer problems with the heat transfer system. It has many advantages compared to others. Therefore, it is used for building air conditioning, etc. Among them, the variable air volume control method (hereinafter referred to as the VAV method), which allows for energy-saving operation, can independently control the temperature of each room with a different heat load, and can also stop air conditioning in rooms that are not in use, allowing you to adjust the required air volume. Operating costs can be reduced by varying the power of the blower depending on the situation, and the capacity of the heat source device can be designed to be smaller by considering the simultaneous usage rate.

There are two types of VAV systems depending on the type of damper for adjusting air volume. One is a method that uses a bypass type VAV unit (damper unit), which adjusts the ratio of the amount of air blown into the room and the amount of air that is returned directly to the heat source equipment (bypassed) depending on the indoor load. This method is often used in systems using packaged air conditioners, where it is difficult to control the capacity of the heat source equipment because the amount of air blown is constant, but there is no energy saving effect by controlling the blower.

The other method uses a diaphragm-type VAV unit, which adjusts the amount of air blown into the room to an arbitrary value depending on the indoor load. This method detects the pressure inside the duct, which changes according to the opening degree of the damper, and controls the capacity of the blower so that this value becomes a certain value. (The temperature of the air inside is controlled to be constant), the required capacity of the heat source equipment is reduced, and at the same time, the power of the blower is also reduced.

FIG. 2 is a system configuration diagram of a conventional air conditioner and the basis of the present invention, in which 1 is a room to be air conditioned, and here a case of three rooms is shown.
Reference numeral 2 denotes an indoor unit placed in the ceiling, which is composed of an air filter 3, a heat exchanger 4, and a blower 5. 6 is a main duct connected to the air outlet of the indoor unit 2, 7 is three branch ducts branched from this main duct, 8 is a throttle-shaped VAV unit inserted in the middle of this branch duct 7, 9 10 is a damper rotatably installed in this VAV unit; 10 is an air outlet installed at the end of the branch duct 7;
is the suction port installed at the bottom of the door of room 1 above,
12 is a ceiling inlet installed on the ceiling of the hallway, 13
14 is a room thermostat installed in each room 1; 15 is a temperature sensor installed in the main duct 6; Similarly, it is a pressure sensor having a detection section provided in the main duct 6, and 17 is a control device attached to the indoor unit 2.

In a conventional air conditioner, the opening degree of the damper 9 is adjusted to an arbitrary position depending on the temperature difference between the set temperature set by the user using each room thermostat 14 and the detected current air temperature. Therefore, the pressure inside the main duct 6 changes depending on the opening degree of the damper 9, which is detected by the pressure sensor 16, and the capacity of the blower 5 is changed to prevent excessive pressure.
In addition, since the outlet air temperature of the heat exchanger 4 changes as the air flow rate changes, this temperature is measured by the temperature sensor 15.
The temperature or circulation amount of the heat medium to the heat exchanger 4 is changed so that the air temperature reaches a preset temperature. The heat exchanger 4 is connected to a heat pump chiller or the like. Further, the air that has been conditioned in the room 1 flows from the suction port 11 through a space such as a hallway to the ceiling suction port 12, and returns to the indoor unit 2 via the suction duct 13.

Note that the blower 5 is well known to be controlled by a constant static pressure control method and a variable static pressure control method using an air volume sensor.

Although FIG. 2 shows a method in which the return air is returned using a corridor or the like, there is also a method in which a return duct is provided from each room 1 to the indoor unit 2 to further improve controllability and energy saving. Further, in FIG. 2, the branch duct 7 is branched from the main duct 6, but there is also a method in which the main duct is not provided and the branch duct 7 is arranged in a dowel-like manner from the indoor unit 2.

In addition to the type shown in FIG. 2, the indoor unit 2 also includes a ceiling-mounted type, a floor-standing type, and the like.

[Problem that the invention seeks to solve]

Since conventional air conditioners are configured as described above, systems using bypass type VAV units have poor energy savings. Also aperture shape
In a system using a VAV unit, if a direct expansion type heat pump is used as the heat source in a small system such as a house or store, the number of rooms used at the same time will be reduced and forced ventilation will not be required. Because there are many dampers, the heat load is small, and each damper may be fully closed or close to fully closed at the same time, making it difficult to control the heat source device (heat pump) and making it impossible to improve the reliability of the device. The dot was hot.

This invention solves the above-mentioned problems.
To provide an air conditioner that improves the reliability of the heat pump without sacrificing room comfort by performing appropriate damper control during low load and smoothing the operation of the heat pump in a system that uses a heat pump as a heat source. The purpose is to

[Means for solving problems]

The air conditioner according to the present invention includes a room thermostat for each room that detects the temperature of each room to which cold and hot air from the heat pump is distributed via a duct, and a heat load controller that detects the temperature of each room based on the output signal of the room thermostat. a damper control amount determining means that determines the damper opening degree of the branch duct based on the measurement result, and a damper control amount determining means that determines whether the total opening degree of each damper determined by the damper control amount determining means is 0% or the minimum. room temperature changing means for temporarily changing the set value of the room thermostat when the temperature falls below the set value; damper control means for controlling the damper opening degree based on the output signal of the damper control amount determining means; A means for detecting the pressure and temperature inside the duct after damper control and measuring the operating state based on the detection signal, a means for determining the rotational speed of the blower using the pressure signal from the operating state measuring means, and a temperature signal. means for determining the capacity of the compressor;
and means for controlling the capacity of the compressor based on the output from the determining means.

[Operation] In this invention, the heat load measuring means calculates the heat load based on the difference between the room temperature set by the room thermostat and the current room temperature, and controls the damper opening degree of the branch duct based on the heat load. The determination is made by the amount determining means. Furthermore, if the determined total opening degree of the dampers is small, the width of the dead zone of the room thermostat or the set room temperature is temporarily changed by the set room temperature changing means in a direction that prolongs the damper closed state, and the damper is controlled by the damper control means. Next, the pressure and temperature in the duct after damper control are detected, and the operating state is measured by the operating state measuring means based on this detection signal, and the rotation speed of the blower is determined by the blower rotation speed determining means based on the pressure signal. The blower is controlled, and the capacity of the compressor is determined by the capacity determining means based on the temperature signal to control the capacity of the compressor. By controlling in this way, the on/off times of the compressor are minimized.

〔Example〕

FIG. 1 is a diagram showing the basic configuration of an air conditioner according to the present invention. In this invention, as is clear from FIG. A damper 9 for adjusting air volume placed in the duct 7, a room thermostat 14 installed in each room 1, a temperature sensor 15 and a pressure sensor 16 installed in the duct 6, The output signal of the tat 14 is input to a heat load measuring means 19, which measures the magnitude of the heat load. Further, 20 is a damper control amount determining means that determines the control amount of the damper 9 based on the output of the thermal load measuring means 19, and 21 is a set room temperature that determines whether or not to change the set room temperature based on the determination result. It is a means of change. 22 is a set room temperature changing means 21
23 is the duct 6 after damper control;
24 is an operating state measuring means for detecting the internal temperature and pressure by a temperature sensor 15 and a pressure sensor 16 and measuring the operating state of the apparatus based on the detection signal, and 24 is a pressure output measured by the operating state measuring means 23. The rotation speed determining means 24 is a blower rotation speed determining means that determines the optimum rotation speed of the blower 5 based on the signal, and a control means 25 that controls the blower 5 based on the determined output is connected to the rotation speed determining means 24. 2
6 is a heat pump (compressor) 18 based on the temperature output signal measured by the operating state measuring means 23.
This capacity determining means 26 includes a capacity controlling means 27 that controls the capacity of the heat pump 18 based on the determined output.
is connected.

FIG. 3 shows the overall configuration of the heat pump 18, which includes a variable capacity (variable rotational speed) compressor 28, a four-way valve 29, an indoor heat exchanger 4, an expansion valve 30, and an outdoor heat exchanger 4. It includes an exchanger 31 and an accumulator 32, which are connected in a ring to form a refrigeration circuit. Moreover, 33 is an outdoor blower attached to the heat exchanger 31 on the outdoor side.

Figures 4a and 4b show details of the VAV unit 8, including a damper motor 34 using a stepping motor that rotates the damper 9 in forward and reverse directions at any angle, and a limit switch that detects the position of the damper 9. 35, limit switch 35
is attached to the damper 9 in the fully closed position.

FIG. 5 is a circuit diagram showing a specific example of the present invention corresponding to the principle configuration shown in FIG.
A microcomputer in 7 includes a CPU 37, a memory 38 for storing control programs and calculation results of the CPU 37, a timer 39, and an input circuit 4.
0 and an output circuit 41. 42 is each room thermostat 14 and temperature sensor 15;
An analog multiplexer 43 to which the detection output of the pressure sensor 16 is input is an A/D converter that converts the output into a digital signal, and the digital signal is applied to the input circuit 40. Reference numeral 44 denotes an operation switch, and its status signal is applied to the input circuit 40 together with the limit switch 35. 45a
~45f is a photocoupler/SSR connected to the output circuit 41 for each control device, and this photocoupler 45
an inverter 46 between the photocoupler a and the compressor 28, an inverter 47 between the photocoupler 45b and the blower 5, an expansion valve controller 48 between the photocoupler 45c and the expansion valve 30, and a photocoupler 45d.
A damper controller 49 is connected between the damper motor 34 and the damper motor 34, and a photocoupler 45
The outdoor blower 33 is connected to e, and the four-way valve 29 is connected to the photocoupler 45f. 50 is an AC and DC power source that drives each device.

Next, the operation of the above embodiment will be explained with reference to FIGS. 6 to 9. FIG. 6 is a main flowchart showing the control program stored in the memory 38 of the microcomputer 36, FIG. 7 is a subroutine flowchart for damper control, FIG. 8 is a subroutine flowchart for blower control, and FIG. 9 is a subroutine flowchart for compressor control. be.

Note that the operation from now on will be explained using heating operation.

First, in step 51, the operation switch 4 is turned on.
4 is set to heating or cooling operation (heating in this case), the operation in which the ON signal is input to the input circuit 40 starts. This operation switch 4
By the operation in step 4, control constants necessary for heating or cooling operation are set in the CPU 37 by the memory 38 (steps 52 and 53). Next, in step 54, each damper 9 is initialized. Damper motor 3
4 is rotated once until the limit switch 35 is operated (until it is fully closed), and then set to the fully open position. At this time, the exact position of the damper 9 is stored in the memory 38. Next, a normal control loop is entered, and the control loop is repeated at regular time intervals by the timer 39 (step 55). First step 56
ON/OFF of the four-way valve 29 and the outdoor blower 33 is determined, and the output circuit 41 outputs the photocouplers 45e and 45e.
The four-way valve 29 and the outdoor blower 33 are controlled via 5f. Next, the process moves to damper control in step 57, and the control program shown in FIG. 7 is executed. That is,
A heat load measurement operation is performed in step ₅₈ in _FIG .
The data is taken into the CPU 37 via . Next, a damper control amount determination operation consisting of steps 59 to 63 begins.
In this operation, it is determined in step 59 whether or not all dampers 9 are already fully closed, and if they are fully closed, the process is bypassed and proceeds to step 65, which will be described later. Otherwise, in step 60 T ₀ and T ₁ are compared and T ₁
When is lower than (T ₀ -t), it is determined in step 61 that the damper 9 is fully open (±t is a dead zone above and below T ₀ ). Further, when T ₁ is higher than (T ₀ +t), it is determined that the damper 9 is fully closed (step 62). Also, T ₁ is (T ₀
±t), it is determined that the opening degree of the damper 9 does not change. The processing in steps 60 to 62 is performed for all n rooms 1, and the end of the processing is determined in step 63. If the answer is ``YES'', the next step 64 to 68 enters into the setting room temperature determination operation. This operation is bypassed to step 69 if it is determined in step 64 that all the dampers 9 are not fully closed in the previous damper control amount determination operation. If not, that is, if all dampers 9 are fully closed, the process moves to step 65 and T ₀
and T ₁ are compared again, and when T ₁ is lower than (T ₀ - _{t s} ), the damper 9 is determined to be fully open in step 66 (t _s is the lower dead zone of T ₀ and the relationship t<t _s ). Further, when T ₁ is higher than (T ₀ −t _s ), it is determined in step 67 that the damper 9 is fully closed. This determination is made for all rooms 1 (step 68). The above results are transmitted from the output circuit 41 to the damper controller 49 via the photocoupler 45d by the damper control operation in the next step 69, and the damper motor 34
Rotate forward or reverse to fully open or close the damper 9. Next, the process moves to indoor blower control in step 70 of FIG. 6, and the control program shown in FIG. 8 is executed. In step 71 of FIG. 8, an operation state measurement operation is performed, and the temperature sensor 15 and pressure sensor 16
signals (T ₂ and P) are sent to analog multiplexer 4
2. Via the A/D converter 43 and input circuit 40
It is taken into the CPU 37. Next, steps 72 to 78 begin to determine the number of rotations of the blower. step 72
Then, it is determined whether all the dampers 9 are fully closed, and if they are, the blower 5 is turned off (step 73) and bypassed to step 79. If it is not fully closed, turn on the blower 5 in step 75, proceed to the next step 74, and measure the ON/OFF state of the blower 5.
If it is in the OFF state, proceed to step 76. In step 76, the set pressure O ₀ in the main duct 6 stored in the memory 38 is compared with the pressure P detected in the previous step 71, and if P ₀ > P, the pressure is determined according to the difference between P ₀ and P. The rotation speed of the blower 5 is increased (step 77). Also, if the relationship P ₀ < P, the rotation speed of the blower 5 is similarly reduced (step 78), and if P is within the dead zone of P ₀ , the rotation speed is not changed and the process moves to the next blower control operation (step 79). . The control output from the CPU 37 is applied from the output circuit 41 to the blower inverter 47 via the photocoupler 45b, where the AC waveform is controlled by the inverter and output to the blower 5 to arbitrarily adjust the rotation speed. Thereafter, the program moves to step 80 of the main program shown in FIG. 6 to control the compressor. Figure 9 shows the processing program, step 81.
A capability determination operation is performed through steps 87 to 87. First, in step 81 it is determined whether all dampers 9 are fully closed, and if they are fully closed, the compressor 28 is turned off in step 82.
and bypass to step 88. Also, if it is not fully closed, turn on/off the compressor 28 in step 83.
Determine the status, and if it is OFF, step 84
Turn on the compressor 28 and proceed to the next step. In step 85, the set air temperature T ₃ in the main duct 6 stored in the memory 38 is compared with the temperature T ₂ detected in the previous step 71, and if T ₃ > T ₂ , T ₃ and T The rotational speed of the compressor 28 is increased according to the difference between the _two (step 86), and if T ₃ <T ₂ , the rotational speed is decreased (step 87). Further, if T ₂ is within the dead zone of T ₃ , the rotation speed is not changed and the process moves to the next capacity control operation (step 88).
The control output from the CPU 37 is applied from an output circuit 41 to an inverter 46 via a photocoupler 45a, which controls the frequency and voltage of the AC power source and outputs it to the compressor 28 to arbitrarily adjust the rotation speed. The capacity of the heat pump 18 changes depending on the rotation speed of the compressor 28, and the temperature of the outlet air of the heat exchanger 34 on the indoor side is adjusted. Next, the expansion valve 30 is controlled (step 89), and further defrost control (step 90) is performed.
is carried out, and the process returns to step 55, whereupon this loop is repeated. Note that steps 89 and 90 and the safety circuit of the system are not closely related to the content of the invention, so details are omitted.

The results of the above control will be explained with reference to operation result explanatory diagrams of FIGS. 10 and 11. For example, when air conditioning (heating) multiple rooms 1 at the same time, the room temperature is lower than the set value immediately after the start of operation, so the damper 9 is operated in a fully open state, and the rotation speeds of the blower 5 and compressor 28 are also controlled to be high. When the room temperature rises and reaches the set value, the damper 9 repeats fully open and fully closed operations to maintain the room temperature within the range of the set value T ₀ ±t. At this time, the amount of air blown is controlled according to the total opening degree of the plurality of dampers 9, and the temperature of the air blown is also kept substantially constant. If all of the dampers 9 happen to be closed, the blower 5 and compressor 28 are temporarily turned off. In this state, the next time any of the dampers 9 is opened is when the room temperature drops to T ₀ -t _s , and the blower 5 and compressor 28 remain OFF until this time. _ts
If the value of ts is increased, the stop time of the compressor 28 will be extended, but the vertical fluctuations in the room temperature will also be large, so the value of t _s is determined in consideration of the reliability associated with ON/OFF of the compressor 28. Note that when only one room is air-conditioned, the room temperature always fluctuates between T ₀ −t _s and T ₀ +t.

In the above embodiment, the damper 9 is fully opened or
The room temperature is controlled by fully closing the damper, but according to this method, warm air is supplied to room 1 at the maximum air volume (wind speed) when damper 9 is open, and the air volume is zero when damper 9 is closed. , the vertical temperature distribution of the room 1 becomes particularly small during heating, making it possible to realize a comfortable living space. In addition to the above method, it is also possible to apply the aperture system used in conventional VAV units to the present invention. In this case, set the total minimum opening of the damper 9 (for example, if there are three VAV units, set the total opening to 50% as the minimum value),
When the opening is below this opening, the blower 5 and compressor 28 are stopped, and _ts is applied to the dead zone.

Further, in the above embodiment, when all dampers 9 are closed,
The width of the dead zone of the set room temperature in all rooms 1 was varied, but the same effect can be obtained by keeping the width of the dead zone constant and changing the set room temperature itself to be lower when heating and higher when cooling. I can do it.

Furthermore, in the above embodiment, the rotation speed was controlled using an inverter in the blower control means 25.
Phase control using a thyristor or the like may also be used.

Further, in the above embodiment, one compressor 28 is used and its capacity is varied by an inverter, but in order to expand the capacity control range, a plurality of compressors are used and an inverter is used in combination to perform capacity control. The capacity can be controlled even more commensurate with the heat load, and the number of times the compressor 28 is turned on and off can be reduced.

Although the above embodiment uses a heat pump as the heat source, the present control method can also be applied to an air conditioner in which an auxiliary heater such as a gas furnace is incorporated into the indoor unit. Furthermore, in the above embodiment, the pressure inside the duct and the air temperature are simultaneously detected, the operating state of the device is measured by the operating state measuring means, and then the blower and compressor are controlled. Alternatively, the air temperature may be detected and the blower controlled, and then the air temperature may be detected and the compressor controlled.

〔Effect of the invention〕

As described above, according to the present invention, when the heat load decreases and all the dampers in each room are closed and the heat pump is stopped, the time until the next damper opens can be extended by changing the set temperature. Since the heat pump is configured to be turned on/off frequently,
This has the effect of eliminating OFF and improving the reliability of the heat pump.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the principle configuration of an air conditioner according to the present invention, Fig. 2 is an overall block diagram of a system using an air conditioner according to an embodiment of the invention and a conventional example, and Fig. 3 is a diagram according to an embodiment of the invention. A configuration diagram of a heat pump, FIG. 4a is a front view showing details of the VAV unit, FIG. 4b is a side view thereof, and FIG. 5 is a circuit diagram showing a specific example corresponding to the principle configuration of the present invention.
Figures 6 to 9 are flowcharts for explaining the operation of the system shown in Figure 5, and Figures 10 and 11 are
The figure is an explanatory diagram for explaining the operation results of the present invention. In the figure, 5 is a blower, 9 is a damper, 14 is a room thermostat, 15 is a temperature sensor, 16 is a pressure sensor, 18 is a heat pump, 19 is a heat load measuring means, 20 is a damper control amount determining means, and 21 is a set room temperature 22 is a damper control means, 23 is an operating state measuring means, 24 is a blower rotation speed determining means,
25 is a blower control means, 26 is a capacity determining means, 2
7 is a capacity control means. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. A duct and a blower that distribute air heated or cooled by a heat pump to each of a plurality of rooms, a damper for controlling air volume arranged in a branch duct of the duct for each room, and a damper for each room. A heat load measuring means for measuring a heat load by inputting a detection signal from an installed room thermostat; a damper control amount determining means for determining the opening degree of the damper based on the output of the heat load measuring means; and a damper control amount determining means. When the total opening degree of each damper determined by the means becomes 0% or less than the minimum set value, the width of the dead zone of the room thermostat or the set room temperature is temporarily changed in a direction that prolongs the closed state of the damper. A set room temperature changing means to be changed, a damper control means for controlling the opening degree of the damper based on the output of the damper control amount determining means, a pressure detector for detecting the pressure in the duct after damper control, and a blowing temperature in the same duct. Operating state measuring means for measuring the operating state of the apparatus by inputting a detection signal from a temperature detector that detects the temperature, a blower rotation speed determining means for determining the rotation speed of the blower based on the output of the operating state measuring means, and blower control means. , and an air conditioner comprising a capacity determining means and a capacity controlling means for determining the capacity of the heat pump based on the output of the operating state measuring means. 2. The air conditioner according to claim 1, wherein the heat load measuring means measures the temperature difference between a set room temperature set in advance by the user and the current room temperature to produce a heat load. 3. The air conditioner according to claim 1 or 2, wherein the opening degree of the damper is determined or controlled to be either 0% or 100% by the damper control amount determining means and the damper control means. Machine. 4. The air conditioner according to claim 1 or 2, wherein the opening degree of the damper is determined or controlled to be an arbitrary opening degree by the damper control amount determination means and the damper control means. 5. The blower rotation speed determining means determines the rotation speed so that the pressure within the duct is approximately constant at a predetermined pressure.
Air conditioner as described in section. 6. The air conditioner according to claim 1, wherein an inverter is used as the blower control means. 7. The air conditioner according to claim 1, wherein the capacity determining means determines the capacity of the heat pump so that the air temperature within the duct is substantially constant at a predetermined temperature. 8. The air conditioner according to claim 1, wherein an inverter is used as the capacity control means.