JPH045979Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to a heat pump type air conditioner equipped with an electric heater for heating refrigerant as an auxiliary heat source for defrosting, and in particular for efficiently performing defrosting operation within a specified power range. It was designed to allow

(Prior art) Some heat pump type air conditioners are equipped with an electric heater to heat the refrigerant as an auxiliary heat source for defrosting, but this is configured to give heat to the refrigerant used for defrosting. Although it is effective as a heat source, simply turning on the electric heater at the same time as the compressor drives will naturally increase the power consumption of the entire device, causing the capacity of the power supply equipment to increase more than necessary, or reducing the contracted power supply. There is a problem that causes an increase in the number of vehicles, so it is necessary to devise ways of driving.

Therefore, attempts have been made in the past to control the power consumption of the entire device so that it does not exceed the specified power value, and an example of this is disclosed in Japanese Utility Model Application Publication No. 110839/1983. The capacity of the electric heater is adjusted so that the sum of the power consumption and the power consumption of the auxiliary electric heater is constant.

(Problem to be solved by the invention) In the conventional device described above, if the compressor is driven at a constant speed and has a constant output such that the maximum rated power is determined at the design stage, it is not possible to use an electric heater in combination. Since the capacity can be set in advance, heating operation can be performed at this set capacity, making it easy to control.However, recently, inverter type compressors have become popular, and the As there is a tendency for devices with variable capacity structures to be used more frequently, various inconvenient problems arise with such simple capacity control.

In other words, in the case of heat pump air conditioners that use an inverter system, the operation is mostly controlled in the range of 30Hz to 120Hz, and by utilizing this variable capacity characteristic, the frequency can be changed during defrost operation.
Many devices increase the frequency to around 120Hz to complete defrost in a short time, but there is a problem with liquid back up.

Moreover, if a capacity control mechanism were provided in this case, it would be uneconomical as it would require the addition of complex and high-cost auxiliary equipment, and there is also the problem that liquid backflow during defrost operation cannot be completely prevented. .

In order to address these problems, the present invention has been developed to eliminate the drawbacks of the conventional technology.In particular, it effectively utilizes the existing compressor capacity control mechanism to increase or decrease the capacity of the compressor, and to increase or decrease the capacity of the electric heater. By configuring the system to provide sufficient heating with its rated capacity, it is possible to suppress the increase in power supply equipment capacity, realize economical operation, and reduce equipment costs. be.

(Means for Solving the Problems) The present invention provides a defrost operation of the variable capacity electric compressor 1, the air-type heat reduction side coil 3, and the heat source side coil 3 in a heat pump type air conditioner. An electric heater 15 is provided in the refrigerant pipe connected to the end of the coil, which is sometimes the outlet side, so as to be able to exchange heat with the refrigerant, and is energized at least during defrost operation.
and a compression function power adjusting means 19 that adjusts the capacity of the electric compressor 1 so that the sum of the electric power of the electric heater 15 and the electric power of the electric compressor 1 in operation is maintained at a predetermined value or less during defrost operation. It is characterized by having the following.

(Function) According to the present invention, when an air conditioner is equipped with a variable capacity electric compressor 1 such as an inverter type, the total power can be easily adjusted by using the existing compressor capacity control device as is.

Moreover, since the electric heater 15 can be used at its maximum required capacity, defrosting can be carried out efficiently and in a short time, and furthermore, it is possible to maintain the refrigerant returning to the compressor as dry gas and prevent liquid compression.

(Example) Hereinafter, an example of the present invention will be described in detail based on the accompanying drawings.

FIG. 1 shows an outside air heat source heat pump type air conditioner according to a first embodiment of the present invention.
is a variable capacity electric compressor, for example, an AC voltage with a frequency that is steplessly converted between 30 Hz and 120 Hz is applied to the induction motor by an inverter, so that the rotation speed of the compressor is stepless. 2 is a four-way switching valve, 3 is an air-to-air type heat source side coil installed on the outdoor side, 4 is a heating expansion mechanism in which a check valve 8 is connected in parallel, Reference numeral 5 denotes a cooling expansion mechanism in which check valves are connected in parallel, 6 a user-side coil installed on the indoor side, and 7 an accumulator. These devices are connected by refrigerant piping and run a known reversible refrigeration cycle. is forming.

The air conditioner described above forms a heating cycle in which the user side coil 6 acts on the condenser and the heat source side coil 3 acts on the evaporator by setting the four-way switching valve 2 to the valve operation indicated by the solid line shown in the figure. On the other hand, by setting the four-way switching valve 2 to the valve operation indicated by the broken line,
A cooling cycle is formed in which the heat source side coil 3 acts on the condenser and the utilization side coil 6 acts on the evaporator.

Note that 13 indicates an outdoor fan for the heat source side coil 3, and 14 indicates an indoor fan for the utilization side coil 6.

In the refrigeration cycle configured as described above, a high-pressure gas pipe connecting the discharge side of the compressor 1 and the inflow port of the four-way switching valve 2 is connected to the heat source side coil 3 and the heating expansion mechanism 4. A hot gas bypass that bypasses the four-way switching valve 2, the user-side coil 6, the check valve 9, and the heating expansion mechanism 4 and guides the hot gas to the heat source-side coil 3 during the heating cycle. A solenoid valve 12 is separately installed in the middle of the hot gas bypass path 11 to be opened during defrosting operation.

Further, in the middle of the gas pipe connecting the heat source side coil 3 and the switching port of the four-way switching valve 2, an electric heater 15 is attached, which is energized at least during the defrost operation and the heating operation. The gas pipe is installed so that heat exchange with the refrigerant flowing inside the gas pipe is possible.

In the air conditioner having the configuration described above, during heating operation, the refrigerant flows in the flow direction indicated by the solid line arrow, and the electric compressor 1 is applied with a voltage with a control frequency between 30Hz and 120Hz. As a result, ability adjustment is achieved,
On the other hand, during cooling operation, the refrigerant flows in the direction of flow indicated by the dashed line arrow, and the capacity of the electric compressor 1 is adjusted by applying a voltage with a control frequency between 30Hz and 90Hz. ing.

Further, the electric heater 15 is supplied with the commercial power supply 10 via the switch circuit 18 during the defrost operation, and is heated at full output.

Further, as described above, the motor of the electric compressor 1 is supplied with an output voltage having a control frequency selected between 30 and 120 Hz via the inverter circuit 17.

Inverter circuit 17 and switch circuit 1
8 is controlled by commands from the control device 16, and is provided so as to feed back the operating state to the control device 16 as control information.

The control device 16 switches the heat pump air conditioner to cooling, heating, and defrosting operations,
It also includes a control means for controlling the operation to maintain the room temperature at a set value, and a compression force adjustment means 19 that is activated only during defrost operation. The electric compressor 1 is monitored so that the sum of the electric power of the electric compressor 1 that is operated to perform the bypass and the electric power of the electric heater 15 that is operated as an auxiliary heat source is always maintained below a specified value, for example, the contract electric power, and the electric compressor is It has a function of adjusting the capacity of the compressor 1, and for example, when the electric heater 15 is energized and is heating at the rated power, the electric compressor 1 is operated at a preset control frequency. It is formed so as to issue a switching command to the inverter circuit 17.

In this case, the preset control frequency corresponds to, for example, the frequency required to give the electric compressor 1 an input of a value smaller than and approximate to the power obtained by subtracting the rated power of the electric heater 15 from the contract power. It is something to do.

The mode of defrosting operation of the air conditioner having the above configuration will be explained below with reference to FIGS. 1 and 2.

When the heat source side coil 3 becomes frosted during the heating operation, a frosting detector (not shown) detects this and issues a defrost operation command, thereby issuing a defrost operation start command (step).

Stopping the outdoor fan 13 and the indoor fan 14 by issuing the start command, and
Open the solenoid valve 12 (Steppro).

In synchronization with the operation of the switch, an energization command is also issued to the electric heater 15 to cause it to heat up (Step 3), and the control frequency (upper limit value) set in advance is ) and issues a command to output the output.

This step corresponds to the operation of the compression force adjustment means 19.

By the way, generally speaking, when considering defrost operation using a constant speed compressor, the high pressure is lower during the defrost operation than during heating operation, and the power consumption of the compressor is small.

Furthermore, compared to the cooling rated condition, the power consumption under the cooling rated condition is considerably larger, so there is sufficient power supply capacity even when the control frequency is increased during defrosting. Therefore, by selecting a heater with a capacity equal to or less than this difference, even if the electric heater 15 is energized during defrosting, the permissible power consumption under not only the cooling rated conditions but also the heating rated conditions will not be exceeded. It is possible to drive.

On the other hand, with a variable speed compressor such as an inverter type, the total power consumption may become too large if the frequency is increased during defrost operation, but by performing the above control,
For example, by regulating the frequency to 90 Hz, an electric heater 15 with a capacity corresponding to the difference in capacity is operated in parallel to keep the refrigerant returning to the compressor dry and to effectively provide the refrigerant with a heat source for defrosting. It is possible.

While the defrost operation is being performed in this way, the defrost detector (not shown) checks the defrost status, and when it detects that the defrost is complete (stipple),
The outdoor fan 13 and the indoor fan 14 are operated, the solenoid valve 12 is closed, and the command sent as the upper limit value to the inverter circuit 17 is canceled to return to the normal control state (Step 2). .

In this way, the defrosting operation is completed and normal heating operation is resumed, and the compressor is operated at a capacity corresponding to the load (step).

Next, FIGS. 3 and 4 are electric circuit block diagrams and flow diagrams according to a second embodiment of the present invention, and in this case, the refrigeration circuit is omitted because it is the same as the example shown in FIGS. .

The compression function force adjustment means 19 in the control circuit 16 of the air conditioner has an element in its input section for detecting the total power consumption of the electric compressor 1 and the electric heater 15. Electric compressor 1
A current detector 20 is used to detect the current flowing through the power supply bus that supplies power to the electric heater 15, and the total power can be determined as a converted value from this current value.

Note that it is also possible to use a power detector that can directly measure power in place of the current detector 20.

The third aspect of the defrost operation of this air conditioner is
This will be explained with reference to the drawings and FIG.

The process from issuing the defrost operation start command (step) to energizing the electric heater 15 (step) is the same as in the first embodiment. When the electric heater 15 is energized, the control circuit 16 checks the current flowing to the power bus ( This detected current I is compared with the maximum setting current Is that has been predetermined as the contract power equivalent current (Step 5), and the I
<Ia, the detected current I is further compared with a high setting current Is' that is slightly lower than the maximum setting current Is (step), and if I≧Is', the current frequency is set to the inverter circuit 17. A command to maintain the current status is issued from the control circuit 16 (stepply), and conversely, if I<Is', the inverter circuit 17 issues a command to maintain the current status.
In contrast, the control circuit 16 issues a command to increase the control frequency during operation by ΔHz, for example, 5Hz (step).

On the other hand, if the result of the check in the above step is I<Is, the control circuit 16 issues a command to the inverter circuit 17 to lower the control frequency during operation by .DELTA.Hz, for example, 5 Hz (step).

In this way, the capacity control is performed so that the detected current I is maintained within the range of Is>I≧Is', and Steps 1 to 1 correspond to the operation of the compression force adjusting means 19.

Generally, a wattmeter called a maximum demand wattmeter that monitors power consumption is installed in the power supply wiring, but this displays the maximum value of electricity over a 15-minute time limit, and this value is used in the contract. This is used as information to judge whether the power is high or low compared to the power, so if you check the steps every 3 to 5 minutes and adjust the operating frequency, you can control the power so that it does not exceed the contract power. And it is possible to achieve the intended purpose.

The steps from the end of defrosting operation to switching to heating operation that are performed in this way ~
The operation of the stepper is similar to that in the first embodiment, so a description thereof will be omitted.

(Effects of the Invention) As detailed above, according to the present invention, during defrosting operation, the electric compressor By adjusting the capacity of machine 1, it is possible to suppress the increase in power supply equipment capacity and the increase in contract power, and to operate rationally without increasing equipment costs and running costs. By defrosting, the defrosting operation can be shortened.

Furthermore, since this method utilizes the existing compression function force control mechanism, the increase in device cost is extremely small simply by adding the electric heater 15, and it is extremely useful when applied to general-purpose machines.

[Brief explanation of the drawing]

1 and 2 are a device circuit diagram and a defrost operation flow diagram according to a first embodiment of the present invention, and a third
FIG. 4 is an electric circuit block diagram and a defrost operation flow diagram according to a second embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... variable capacity electric compressor, 3... air type heat source side coil, 15... electric heater, 19... compression function force adjustment means.

Claims (1)

[Scope of utility model registration request] The variable capacity electric compressor 1, the air-type heat source side coil 3, and the refrigerant piping connected to the coil end that becomes the outlet side during defrosting operation of the heat source side coil 3 are provided so as to be able to exchange heat with the refrigerant. The electric heater 15 is energized during the defrost operation, and the electric compressor 1 is operated so that the sum of the electric power of the electric heater 15 during the defrost operation and the electric power of the electric compressor 1 in operation is maintained at a predetermined value or less. 1. A heat pump type air conditioner characterized by comprising: compression function force adjustment means 19 for adjusting capacity.