JP2504595B2 - Compression type heat pump device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention provides an inverter control means for inverter-controlling a compressor according to a temperature control load for cooling or heating a temperature control target to control the temperature. The present invention relates to a provided compression heat pump device.

[Conventional technology]

In the compression heat pump device as described above, there is a lower limit rotation speed of the compressor for the purpose of protecting the compressor in controlling the inverter according to the temperature control load. Load value (in other words, lower limit value of output frequency in inverter control)
However, under the condition that the temperature control load is smaller than the corresponding lower limit load value, the temperature control output cannot be adjusted by the inverter control of the compressor. In some cases, instead of the control, ON-OFF control of the compressor according to the temperature control load is performed.

FIGS. 4 and 5 respectively show the device configuration of a conventional device of this type, and FIG.
Device configuration when cooling temperature is controlled by the heat absorption function of
FIG. 5 shows an apparatus configuration in which the circulating fluid in the flow path 7 is heated and controlled by the heat radiation function of the condenser 2.

In FIG. 4 and FIG. 5, S ₁ is a control index for controlling the compressor according to the temperature control load, and the temperature of the circulating fluid that has passed through the cooling part of the evaporator 4 and the heating part of the condenser 2 (that is, adjustment). Temperature sensor for detecting temperature), 12 is this temperature sensor S ₁
An inverter controller that controls the compressor 1 based on the detected temperature of the compressor 1, 19 is an auxiliary control instead of the inverter control, and the compressor 1 is turned on based on the detected temperature of the temperature sensor S _1.
An ON-OFF controller for OFF control, 11 is an inverter controller 12 when the temperature control load detected by the rotation sensor S ₂ and the compressor speed in the inverter control state drops to the lower limit speed.
Corresponding lower limit load value or more, it is determined that the compressor control from the inverter control by the inverter controller 12
It is a judgment means for control switching for switching to ON-OFF control by the ON-OFF controller 19.

[Problems to be Solved by the Invention]

However, in the case of ON-OFF control, there is a problem that the useful life of the compressor and compressor motor decreases due to frequent ON-OFF, and there is a large fluctuation in the adjustment temperature due to ON-OFF of the compressor. However, there is a problem that the temperature control accuracy is greatly reduced in the underload condition as compared with the normal load condition in which the inverter control is executed.

In particular, regarding the decrease in temperature control accuracy, there is a risk of burning the compressor motor if ON-OFF is performed with a too short cycle in the ON-OFF control, and the ON-OFF cycle is longer than a certain length. ON period and OF
The change in the adjustment temperature that occurs in each of the F periods becomes even larger, and thus the decrease in the temperature adjustment accuracy becomes more remarkable.

In view of the above circumstances, the object of the present invention is to control the temperature in an underload condition in which the temperature control load is smaller than the corresponding lower limit load value of the inverter control without causing a reduction in the service life of the compressor or the compressor motor. Also, there is a point to be able to perform with high accuracy.

[Means for solving the problem]

The feature of the invention according to claim 1 is that the temperature control is performed by cooling or heating an object to be temperature-controlled, and an inverter control means for inverter-controlling the compressor according to the temperature control load is provided. A load increasing means for changing the state to the target and the load increasing side, and it is determined whether or not the temperature control load in a state in which the load increasing means is inactive is an underload condition smaller than the corresponding lower limit load value of the inverter control means. The load determining means and the auxiliary control means for actuating the load increasing means in the underload situation are provided based on the determination result of the load determining means.

The characteristic configuration of the invention according to claim 2 is the invention according to claim 1, wherein the auxiliary control means sets the temperature control load to a constant target equal to or higher than the corresponding lower limit load value of the inverter control means in the underload situation. The degree of action of the load increasing means is adjusted so as to maintain the value.

[Work]

In the invention according to claim 1, the load control means is actuated to change the state of the temperature control target to the load increasing side, so that the temperature control load is intentionally changed to the original temperature control load (that is, the load control means is not However, if the original temperature control load itself is equal to or higher than the corresponding lower limit load value of the inverter control means, the load increasing means is not operated and the original temperature control load is applied. As it is, the inverter control means performs inverter control of the compressor in accordance with the temperature control load, thereby adjusting the balance between the temperature control output and the temperature control load.

On the other hand, regarding the load situation, the load determination means determines that the original temperature regulation load (the temperature regulation load when the load increasing means is inactive) is smaller than the corresponding lower limit load value of the inverter control means. When the determination is made, the auxiliary control means actuates the load intensifying means based on this determination to increase the temperature control load above the original temperature control load. A temperature adjustment operation with a temperature adjustment load equal to or higher than the corresponding lower limit load value, that is, a balance adjustment between the temperature adjustment output and the temperature adjustment load while continuing the compressor operation equal to or higher than the lower limit rotation speed is enabled.

In the invention according to claim 2, in the above-mentioned underload condition, the degree of action of the load intensifying means is adjusted so as to maintain the temperature control load at a constant target value equal to or higher than the corresponding lower limit load value of the inverter control means (that is, By adjusting the amount of artificial load increase from the original temperature control load), when the original temperature control load is relatively large, the increase amount of the temperature control load by the load intensifying means becomes small. In comparison with the case where the temperature control load is constantly increased regardless of the size of the original temperature control load in an excessively low load situation, energy is wasted by performing temperature control after the temperature control load is intentionally increased (that is,
In the case of cooling temperature control, less energy is wasted by intentionally heating the temperature control target and then cooling temperature control, and in the case of heating temperature control, less energy waste is required by intentionally cooling the temperature control target and then heating temperature control). To do.

The effect of reducing the energy waste is maximized when a value equal to the corresponding lower limit load value of the inverter control means is adopted as the constant target value.

〔The invention's effect〕

According to the present invention according to claim 1, even in an underload condition in which the original temperature control load is smaller than the corresponding lower limit load value of the inverter control means, the temperature control is performed while the compressor operation above the lower limit rotation speed is continued. Since it is possible to adjust the balance between the output and the temperature control load, it is not necessary to use ON-OFF control as in conventional devices, and it is possible to prevent the useful life of compressors and compressor motors from decreasing due to frequent ON-OFF. Further, it is possible to improve the temperature control accuracy in an underload condition by eliminating the fluctuation of the regulated temperature due to ON / OFF of the compressor.

By the way, in the above-mentioned underload condition, another method is available to enable the balance adjustment between the temperature control output and the temperature control load while continuing the compressor operation at the lower limit rotation speed or more. As shown in Japanese Patent Laid-Open No. 196555, in the case of cooling temperature control, depending on the detected pressure on the low pressure side of the compressor,
The compressor is controlled by an inverter, and the refrigerant circulation amount is adjusted by an electrically operated valve at the evaporator outlet according to the detected temperature of the cooling temperature control target in the evaporator. When the above-mentioned underload situation occurs, the compressor is forcibly held at the lower limit rotation speed, and this holding causes the pressure on the low pressure side of the compressor to further decrease. By opening the bypass pipe connecting the low-pressure side and the high-pressure side of the high-pressure gas and guiding the high-pressure gas to the low-pressure side, the pressure on the low-pressure side does not drop to the set value of the stop pressure switch, and the compressor can continue operating. There is something I did.

However, such another method involves switching the refrigerant circulation path on the refrigerant circuit side by opening and closing the bypass pipe,
Further, since this path switching is a short-circuit and short-circuit interruption between the low pressure side and the high pressure side of the compressor with a large pressure difference, the refrigerant is switched between the operation under the normal load condition and the operation under the underload condition. The operation of the circuit tends to become uneasy, especially when the cooling temperature control load fluctuates at the boundary between the underload condition and the normal load condition, the opening and closing of the bypass pipe is repeated and the refrigerant circulation path is frequently switched. As a result, this instability becomes particularly noticeable, and the instability of the refrigerant circuit operation at the time of such operation switching causes a decrease in the service life of the device and a decrease in the temperature control accuracy.

In addition, even when the short-circuit recirculation amount of high-pressure gas to the low-pressure side is adjusted by the capacity adjustment valve of the bypass pipe during operation in an under-loaded condition in which the bypass pipe is open, the high-pressure side and high-pressure side of the compressor are Since the pressure difference with the side is large, it is difficult to accurately and stably adjust the short-circuit recirculation amount with a valve, and the circulation state of the refrigerant (particularly the pressure distribution in the refrigerant circuit) easily fluctuates. Therefore, it also accompanies the fluctuation of the heat radiation capacity in the condenser.
Even if you adjust the refrigerant circulation amount with the electric valve at the evaporator outlet,
As a result, the adjustment becomes unstable, and as a result, the temperature control accuracy decreases in the operation under the underload condition as compared with the operation under the normal load condition.

In this respect, according to the first aspect of the present invention, the under load is increased by increasing the temperature control load itself by the load increasing means without switching the refrigerant circuit side such as short-circuiting the low pressure side and the high pressure side of the compressor. Since it is possible to operate the compressor at the lower limit rotation speed or more in the situation, it is possible to avoid the instability of the refrigerant circuit operation due to the operation switching as described above and the fluctuation of the refrigerant circulation state in the operation in the underload condition. Therefore, compared with the other method described above, it is possible to more effectively achieve the intended purpose of improving the durability of the device and improving the accuracy of temperature control in an underloaded condition.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, an increase in operating cost can be suppressed by preventing energy waste.

〔Example〕

First Embodiment FIG. 1 shows the device configuration in the cooling temperature control operation, 5 is a refrigerant flow path for circulating the refrigerant in the order of the compressor 1, the condenser 2, the expansion valve 3, and the evaporator 4, and 7 is heat. A load-side flow path that circulates air to be temperature-controlled over the load section 6 and the heat exchange section of the evaporator 4, 8a is an atmosphere supply path that guides the atmosphere to the heat exchange section of the condenser 2, and 8b is heat exchange of the condenser 2. Is a discharge path for releasing the heat-exchanged atmosphere from the section, and is a compression type that cools the temperature of the temperature-controlled air by the endothermic action of the evaporator 4 while radiating heat to the atmosphere by the heat radiating action of the condenser 2. It is used as a cooling device using a heat pump.

In addition, in this cooling device, the above-mentioned heat load part 6 is made into a room,
In addition, the air conditioner serves as the air conditioner in the usage mode in which the temperature-controlled air is the indoor air.

Reference numeral 9 denotes an exhaust passage for discharging a part of the temperature control target air derived from the heat load portion 6 to the heat exchange portion of the evaporator 4, and 10
Is a ventilation path that mixes the atmosphere (outside air) with the temperature-controlled air that is sent to the heat exchange section of the evaporator 4 after being partially discharged to the exhaust path 9. Valve V ₁ , V
₂ is installed.

S ₁ is a temperature sensor that detects the temperature of the temperature-controlled air sent from the heat exchange section of the evaporator 4 (that is, the temperature after cooling temperature control), and S ₂ is the rotation speed that detects the rotation speed of the compressor 1. As a control configuration for automatically operating the compressor 1 and the flow rate adjusting valves V ₁ and V ₂ based on the detection information of the sensors S ₁ and S ₂ , the following control means (a) to (d) are provided. Equipped.

(B) Rotation speed detection sensor S ₂ and control switching means described later
It is a means for instructing the switching between the inverter control and the auxiliary control based on the information from 14, and in the inverter control state, the rotation speed detected by the rotation speed detection sensor S ₂ is the lower limit rotation speed of the compressor 1 (generally, 30 rpm), an instruction to continue the inverter control is issued, and when the rotational speed detected by the rotational speed detection sensor S ₂ drops to the lower limit rotational speed of the compressor 1 in the inverter control execution state, an excessive underload occurs. When the situation is a situation, the determination means 11 for control switching for instructing the auxiliary control, (b) When the inverter control is instructed from the determination means 11,
As the inverter control, the compressor 1 is inverter-controlled (specifically, based on the temperature detected by the temperature sensor S ₁ so that the temperature of the temperature-controlled air sent from the heat exchange section of the evaporator 4 is maintained within a set temperature range. Specifically, when the auxiliary control is instructed from the inverter controller 12 for controlling the rotation speed of the compressor electric motor (inverter control), and (c) the determination means 11, the auxiliary control is performed from the heat exchange section of the evaporator 4. Auxiliary controller 13, which controls the opening of both flow rate adjusting valves V ₁ , V ₂ based on the temperature detected by temperature sensor S ₁ so that the temperature of the temperature-controlled air to be sent out is maintained within the set temperature range, ) In the auxiliary control state by the auxiliary controller 13, when the flow control valves V ₁ and V ₂ have the minimum opening (minimum flow rate state) and the temperature detected by the temperature sensor S ₁ exceeds the upper limit of the set temperature range. , The judgment means 11 is supplemented when the normal load condition is reached. Inverter control return control switching means 14 for instructing return from auxiliary control to inverter control.

In the inverter control state, both flow rate adjusting valves V ₁ and V ₂ are fully closed, and in the auxiliary control state, the compressor rotation speed is maintained at the lower limit rotation speed.

That is, in the above device configuration, the inverter controller
Reference numeral 12 constitutes an inverter control means for controlling the compressor 1 by an inverter according to the load of the cooling temperature control, and the ventilation path 10 and the flow rate adjusting valve V ₂ provided therein are such that the outside air is mixed into the temperature control target air. Thus, the load increasing means for changing the state of the temperature-controlled air to the load increasing side (that is, temperature increase) is configured, and the determining means 11 and the control switching means 14 are the cooling temperature in a state where the load increasing means is inactive. Configure a load determination means for determining whether or not the key load is an overload condition smaller than the corresponding lower limit load value of the inverter control means, and the auxiliary controller 13 is based on the determination result of the load determination means. An auxiliary system for operating the load intensifying means in the above-mentioned overload condition and adjusting the degree of action of the load intensifying means so as to keep the cooling temperature control load at a constant target value equal to the corresponding lower limit load value of the inverter control means. Configure the means.

Second Embodiment FIG. 2 shows a device configuration in the heating temperature control operation, 5 is a refrigerant flow path for circulating the refrigerant in the order of the compressor 1, the condenser 2, the expansion valve 3 and the evaporator 4, and 7 is heat. A load side flow path that circulates the temperature-controlled air over the load section 6 and the heat exchange section of the condenser 2, 8a is an atmosphere supply path that guides the atmosphere to the heat exchange section of the evaporator 4, and 8b is heat exchange of the evaporator 4. Is an atmosphere discharge path for leading out the heat-exchanged atmosphere from the portion, and heat-adjusts the temperature of the temperature-controlled air by the heat radiating (heating) function of the condenser 2 while absorbing heat from the atmosphere by the heat absorbing function of the evaporator 4. It is a heating device using a compression heat pump.

In addition, in this heating device, the above-mentioned heat load unit 6 is made into a room,
Moreover, it becomes a heater in a usage pattern in which the temperature-controlled air is indoor air.

Reference numeral 9 denotes an exhaust path for discharging a part of the temperature control target air derived from the heat load section 6 to the heat exchange section of the condenser 2, and 10
Is a ventilation path that mixes the atmosphere (outside air) with the temperature-controlled air that is sent to the heat exchange section of the condenser 2 after being partially discharged to the exhaust path 9. Valve V ₁ , V
₂ is installed.

S ₁ is a temperature sensor that detects the temperature of the temperature-controlled air sent from the heat exchange section of the condenser 2 (that is, the temperature after heating temperature control), and S ₂ is the rotation speed that detects the rotation speed of the compressor 1. A sensor is a control configuration for automatically operating the compressor 1 and the flow rate adjusting valves V ₁ and V ₂ based on the detection information of the sensors S ₁ and S ₂ , and has the following (a ′) to (d ′). Equipped with control means.

(B) is a means for instructing switching between inverter control and auxiliary control based on information from the rotation speed detection sensor S ₂ and control switching means 14 described later. When the rotation speed detected by the detection sensor S ₂ is higher than the lower limit rotation speed of the compressor 1 (generally about 30 rpm), the rotation speed detection sensor S ₂ is instructed to continue execution of the inverter control and in the execution state of the inverter control. When the detected rotation speed of 1 is lowered to the lower limit rotation speed of the compressor 1, the control means for judging the switching 11 and (b ') for judging the auxiliary control as if the underload condition occurs, the inverter control is instructed. As its inverter control, the compressor 1 is turned on based on the temperature detected by the temperature sensor S ₁ so that the temperature of the temperature-controlled air sent from the heat exchange section of the condenser 2 is maintained within the set temperature range. When the auxiliary control is instructed from the inverter controller 12 for controlling the burner control (specifically, the rotation speed of the electric motor for the compressor is controlled by the inverter) and the (c ′) determination means 11, the condenser 2 is used as the auxiliary control. In order to maintain the temperature of the temperature controlled air sent from the heat exchange part of
Auxiliary controller 13 for controlling the opening of both flow rate adjusting valves V ₁ , V ₂ based on the temperature detected by temperature sensor S ₁ , (d) In the auxiliary control state by auxiliary controller 13, flow rate adjusting valves V ₁ , V ₂ Is the minimum opening (minimum flow rate state) and the temperature detected by the temperature sensor S ₁ is below the lower limit of the set temperature range, it is judged that the normal load condition has occurred and the judgment means 11 returns from the auxiliary control to the inverter control. Inverter control recovery control switching means 14.

In the inverter control state, both flow rate adjusting valves V ₁ and V ₂ are fully closed, and in the auxiliary control state, the compressor rotation speed is maintained at the lower limit rotation speed.

That is, in the above device configuration, the inverter controller
Reference numeral 12 constitutes an inverter control means for controlling the compressor 1 by an inverter in accordance with the load of the heating temperature control, and the ventilation path 10 and the flow rate adjusting valve V ₂ provided therein are such that the outside air is mixed into the temperature control target air. Thus, the load increasing means for changing the state of the temperature-controlled air to the load increasing side (that is, the temperature decreasing) is configured, and the determining means 11 and the control switching means 14 are the heating temperature in a state where the load increasing means is inactive. Configure a load determination means for determining whether or not the key load is an overload condition smaller than the corresponding lower limit load value of the inverter control means, and the auxiliary controller 13 is based on the determination result of the load determination means. , An auxiliary system for operating the load intensifying means in the above-mentioned overload condition and adjusting the degree of action of the load intensifying means so as to maintain the heating temperature control load at a constant target value equal to the corresponding lower limit load value of the inverter control means. Configure the means.

When the cooling device using the compression heat pump in the first embodiment is used as an air conditioner, or when the heating device using the compression heat pump in the second embodiment is used as a heater, the compressor 1 and the condenser 2 are used. , The expansion valve 3, the heat pump portion including the evaporator 4, the sensors S ₁ and S ₂ , the control means 11 to 14, and the blower B and other main components are housed in a single device case 16 as shown in FIG. Then, a packaged air conditioner type air conditioner / heater which connects the forward / backward paths of the air circulation flow path 7, the atmosphere supply path 8a, and the atmosphere discharge path 8b to the device case 16 may be used.

At this time, a part of the air whose cooling temperature is controlled in the heat exchange part of the evaporator 4 and a part of the air whose heating temperature is controlled in the heat exchange part of the condenser 2 are blown out to the package air conditioner installation chamber.
It is also possible to form 17 in the device casing 16 and thereby cool or heat the packaged air-conditioner installation chamber together by blowing cold air or warm air from the air outlet 17.

Further, a slide damper 18 for adjusting the amount of blown air may be provided at the blowout port 17 so that the cooling strength and the heating strength of the package air conditioner installation room can be adjusted appropriately by adjusting the damper 18.

[Another embodiment]

(1) In the cooling temperature control, not only the atmosphere but also natural water or cooling water from the cooling tower can be used as the heat radiation source. In the heating temperature control, the heat absorption source can be natural air or drainage in addition to the atmosphere. Any suitable one can be adopted.

(2) In the cooling temperature control, the load unit 6 may be any space such as a cooling target space, a freezing room, and a refrigerating room. In the heating temperature control, the heat load unit 6 is a heating target space or a hot water supply facility. Good.

(3) The temperature control target in the cooling temperature control or the heating temperature control may be water or brine in addition to air.

(4) When the inverter control or the auxiliary control according to the temperature control load is performed based on the detection information, the detection information is as follows.
Instead of adopting the temperature of the temperature control target after passing through the heat exchange parts of the evaporator 4 and the condenser 2 as in the above-described embodiment, the evaporator 4 is used.
And the temperature of the temperature control target sent to the heat exchange section of the condenser 2, the evaporator 4
A suitable temperature such as the temperature of the condenser 2 or the pressure of the refrigerant can be used.

(5) As the load increasing means in the cooling temperature control, the method of mixing the outside air as in the above-described embodiment is adopted, or the method of mixing the heated air from the atmosphere discharge passage 8b into the temperature control target air, or
An appropriate method such as a method using a heat exchanger or a heater can be adopted, and as the load increasing means in heating temperature control, the outside air mixing method as in the above-mentioned embodiment is adopted, and the atmosphere discharge path is used.
An appropriate method such as a method of mixing the cooling air from 8b with the air to be temperature-controlled or a method of using a heat exchanger can be adopted.

It should be noted that, in an underload condition, performing the temperature control in a state where the temperature control load is increased by the load intensifying means results in an increase in energy waste simply. In the heating, when adopting the method of increasing the temperature control load by mixing the outside air into the temperature-controlled air as in the above-described embodiment, the increase in energy consumption due to the outside air mixture improves the indoor ventilation state due to the outside air mixture. Will be compensated in the form.

(6) The specific configuration of the control system can be modified in various ways. For example, the function of the control switching means 14 can be provided in the determination means 11, or a microcomputer can be used to construct the control system.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1, FIG. 2 and FIG. 3 show an embodiment of the present invention.
The figure is a block diagram showing the device configuration in the cooling temperature control operation, the second
The figure is a block diagram showing the device configuration in the heating temperature control operation,
The figure is a perspective view of a package type air conditioner. 4 and 5 show a conventional example, FIG. 4 is a block diagram showing a device configuration in a conventional cooling temperature control operation, and FIG. 5 is a block diagram showing a device configuration in a conventional heating temperature control operation. Is. 1 ... Compressor, 12 ... Inverter control means, 10, V ₂ ...... Load increase means, 11,14 ...... Load determination means, 13 …… Auxiliary control means.

Claims (2)

(57) [Claims] 1. A compression type heat pump device provided with an inverter control means (12) for controlling the compressor (1) by an inverter according to the temperature control load for cooling or heating a temperature control target to control the temperature. there, the load enhancement device for a state change of the temperature control target load increase side (10, V _2), the load enhancement device (10, V ₂₎ is temperature control load at the non-operating state the inverter control means The load judgment means (11, 14) for judging whether or not the underload condition is smaller than the corresponding lower limit load value of (12), and the above-mentioned underload based on the judgment result of the load judgment means (11, 14). In the situation, the load increasing means (10, V ₂ )
Compression heat pump device provided with auxiliary control means (13) for operating 2. The load control means (13) for maintaining the temperature control load at a constant target value equal to or higher than a corresponding lower limit load value of the inverter means (12) in the underload condition. The compression heat pump device according to claim 1, wherein the compression heat pump device is configured to adjust the degree of action of 10, V ₂ ).