JPS62200124A - Air conditioner of heat pump type - Google Patents

Abstract

PURPOSE:To reduce the amount of blast and circulate cool air in a room in order not to give bad feeling to occupants of the room by using in the reversed direction the multi-vane fan of a blower on the indoor side during defrosting operation. CONSTITUTION:An indoor blower 12 of this heat pump type air conditioner has a multi-vane fan 13 which consists of an impeller 13a and a casing 13b. During room heating operation, the impeller 13a is rotating in the direction shown by a solid line arrow mark in the drawing. When frost is accumulated on a heat exchanger 3 on the outdoor side, a defrosting control device 15 is actuated and the impeller 13a of the blower 12 on the indoor side rotates in the direction shown by the arrow mark in a broken line in the drawing, and as soon as an outdoor blower 7 stops, a four-way change-over valve 2 is changed over to start defrosting operation. When the rotation of the impeller 13a is reversed, the blast of the blower on the indoor side is reduced a great deal in comparison with the blast during the room heating operation. With this arrangement it is possible during the defrosting operation to reduce the amount of blast very much without reducing the rotational speed of the blower 12 on the indoor side and circulate cool air in the room during the defrosting operation.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a heat pump type air conditioner.

Conventional technology In recent years, heat pump air conditioners have become widely popular because they have the advantage of being able to perform heating and cooling operations with a single unit. As the capacity decreases, it is necessary to perform a defrost operation when more than a certain amount of frost adheres, and heating cannot be performed during the defrost operation. Sometimes the blower inside the room was turned on.

An example of the conventional heat pump type air conditioner mentioned above will be described below with reference to the drawings.

FIG. 4 shows a schematic diagram of a refrigeration cycle of a conventional heat pump type air conditioner. In FIG. 4, reference numeral 1 denotes a compressor that sucks in, compresses, and discharges refrigerant. On the discharge side of the compressor 1, there is a four-way switching valve 2. Outdoor heat exchanger 3. A capillary tube 4 as a pressure reducing device and an indoor heat exchanger 6 are sequentially connected. Further, the indoor heat exchanger 5 is connected to the suction side of the compressor 1 via the four-way switching valve 2 in series, and constitutes a heat pump type refrigeration cycle 6.

Further, an outdoor fan 7 is provided corresponding to the outdoor heat exchanger 3, and an indoor fan 8 is provided corresponding to the indoor heat exchanger 6. The indoor blower 8 is composed of a fan body and a single-phase motor with a rotation speed switching tap. Further, a frosting detector 1o including a detection section 9 is provided near the outdoor heat exchanger 3. The frost detector 10 also communicates with the indoor blower 7, the outdoor blower 7, and the four-way switching valve 2, and constitutes a defrost control device 11 that controls the heating operation.

The operation of the heat pump air conditioner configured as above will be described below.

First, during heating operation, the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 is circulated to the indoor heat exchanger 5 side, that is, in the direction shown by the solid arrow. The indoor air circulated by the indoor blower 8 is then warmed by the sensible heat and latent heat of condensation of the refrigerant in the indoor heat exchanger 6. On the other hand, at this time, the outdoor heat exchanger 3 performs an evaporation action by exchanging heat with the outside air circulated by the outdoor fan 7. A so-called frosting phenomenon occurs in which moisture in the outside air freezes and accumulates. Next, when this frosting phenomenon increases over time and becomes a hindrance to heat exchange, the frosting detector 10 detects this, and the defrosting control device 11 is activated in conjunction with this detection operation.

When the defrosting control device is activated, the tap for switching the rotational speed of the motor of the indoor fan 8 is switched, and the rotation speed of the indoor fan 8 is lowered to reduce the indoor air volume, and at the same time, the outdoor fan 7 is stopped, and at the same time The switching valve 2 switches, and the compressor 1
The high temperature and high pressure gas refrigerant discharged from the outdoor heat exchanger 3
In other words, the air is circulated in the same direction as during cooling operation as indicated by the broken line arrow. At this time, the indoor heat exchanger 6
In this case, heat is exchanged with indoor air circulated by the indoor blower 8 to effect evaporation, and in the outdoor heat exchanger 3, adhering frost is defrosted by the sensible heat and latent heat of condensation of the refrigerant.

Problems to be Solved by the Invention However, in the above configuration, since the indoor fan 8 is operated during the defrosting operation, the indoor heat exchanger 5 exchanges heat with indoor air and blows cold air indoors. It turns out. Therefore, during defrosting operation, it is necessary to set the air volume of the indoor fan 8 as low as possible (approximately less than % of heating operation) to reduce the distance that the cold air reaches so as not to cause discomfort to the occupants in the room. be. By the way, the indoor blower 8 uses a single-phase motor tap switching method, and there are two ways to reduce the motor rotation speed: one is to switch the taps on the main winding side, and the other is to switch the taps on the auxiliary winding side. There is a limit to the rate of decline in numbers. In the tap switching method on the main winding side, there is a lower limit to low rotation in terms of the winding occupancy rate in the slot section of the stator core, and in the tap switching method on the auxiliary winding side, there is an excessive current in the winding under low rotation conditions. There is a limit to how low the rotation speed can be reduced because the windings experience an abnormal temperature rise. Conventionally, the air volume of the indoor blower could not be sufficiently reduced during defrosting, and cooled air would circulate indoors, impairing comfort.

Means for Solving the Problems In order to solve the above problems, the heat pump air conditioner of the present invention has a compressor, a four-way switching valve, an outdoor heat exchanger, a pressure reducing device, an indoor heat exchanger, etc. sequentially communicate,
An outdoor blower is installed corresponding to the outdoor heat exchanger, and an indoor blower consisting of a single-phase motor and a multi-blade fan is installed corresponding to the indoor heat exchanger. It has a frost detector with a detection part facing the vicinity of the outside heat exchanger, and in conjunction with the detection operation of the frost detector, stops the outdoor fan, reverses the rotational direction of the indoor fan, and It is equipped with a defrosting control device that switches the four-way switching valve.

Effect: With the above-described configuration, the present invention obtains the required air volume by rotating the multi-blade fan of the indoor blower in the forward direction during heating operation, and rotates the multi-blade fan of the indoor blower in the reverse direction during defrosting operation. By using this system, the air volume can be reduced without reducing the aerodynamic performance of the indoor blower and reducing the motor rotation speed.

EXAMPLE Hereinafter, a heat pump type air conditioner according to an example of the present invention will be described with reference to the drawings. Incidentally, the same parts as those in the conventional example are given the same reference numerals, and the description thereof will be omitted.

FIG. 1 shows a schematic diagram of a refrigeration cycle in an embodiment of the present invention, and 12 is an impeller 13a.

This is an indoor blower composed of a multi-blade fan 13 made up of a casing 13b and a single-phase motor 14 (not shown). Reference numeral 16 denotes a defrosting control device (not shown in detail) which stops the outdoor fan 7, reverses the rotational direction of the indoor fan 120, and switches the four-way switching valve 2 in conjunction with the detection operation of the frost detector 10. be.

The operation of the heat pump air conditioner configured as described above will be explained below using FIGS. 1 to 3.

During heating operation, the impeller 13a of the multi-blade fan 13 is rotated by the single-phase motor of the indoor blower 12 in the direction of the solid line arrow in FIG. 2, that is, in the positive direction as a multi-blade fan. Next, when frost accumulates on the outdoor heat exchanger 3 to prevent heat exchange, the arrival λi detector 10 detects this, and the defrost control device 16 operates in conjunction with this detection operation. . When the defrosting control device 15 operates, the indoor blower 12
The direction of rotation of the single-phase motor is reversed, and the impeller 13a of the multi-blade fan 13 rotates in the direction of the dashed arrow in FIG. 2, that is, in the opposite direction as a multi-blade fan. At the same time, the outdoor blower 7 is stopped and the four-way switching valve 2 is switched to enter defrosting operation. Third
The figure shows the aerodynamic characteristics of the multi-blade fan 13.
16 is the characteristic when rotating in the forward direction during heating operation, 16 is the characteristic when rotating in the reverse direction during defrosting operation, and 18 is the ventilation resistance curve of the indoor heat exchanger 3. When the impeller 13b of the multi-blade fan 13 is rotated in the opposite direction, the impeller 13
Since a is a swept-back blade, the impeller exit speed of the internal airflow is greatly reduced compared to when the blade is rotated in the forward direction, that is, acts as a forward-moving blade. Moreover, when the impeller 13a is rotated in the opposite direction, the direction of the impeller exit of the internal airflow is opposite to the expansion direction of the casing 13b, which reduces the efficiency of converting the dynamic pressure component of the impeller exit airflow into a static pressure component. Aerodynamic performance deteriorates. Therefore, the air volume B of the indoor fan during defrosting operation is smaller than the air volume A during heating operation.
1].

As described above, the present invention rotates the single-phase motor 14'i of the indoor blower 12 in the opposite direction during defrosting operation, and rotates the impeller 13a of the multi-blade fan 13 in the opposite direction. The air volume can be greatly reduced without lowering the rotational speed of the single-phase motor 14, and cold air will not be circulated indoors during defrosting operation to cause discomfort to the occupants.

Moreover, unlike when the taps of a single-phase motor are changed to lower the rotation speed, an excessive external current does not flow through the windings and cause overheating, and there is no fear of accidents such as seizure caused by this.

Effects of the Invention As described above, the present invention sequentially connects a compressor, a four-way switching valve, an outdoor heat exchanger, a pressure reducing device, an indoor heat exchanger, etc., and arranges them in correspondence with the outdoor heat exchanger. An indoor blower consisting of a single-phase motor and a multi-blade fan is installed in correspondence with the installed outdoor blower and the indoor heat exchanger,
A frost detector is provided with a detection unit facing near the outdoor heat converter, and in conjunction with the detection operation of the frost detector, the outdoor fan is stopped and the indoor fan is rotated in the direction of rotation. By providing a defrost control device that performs reverse rotation and switching of the four-way switching valve described above, the single-phase motor of the indoor blower is reversed during defrosting operation, and the impeller of the multi-blade fan is rotated in the opposite direction as the multi-blade fan. By doing so, the air volume can be significantly reduced without lowering the rotational speed of the single-phase motor, and cold air will not be circulated indoors during defrosting operation and will not cause discomfort to the occupants. Moreover, unlike when the taps of a single-phase motor are changed to lower the rotation speed, an excessive current does not flow through the windings and cause overheating, and accidents such as seizure caused by this can be prevented.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the refrigeration cycle of a heat pump type air conditioner in an embodiment of the present invention, Fig. 2 is a sectional view of a multi-blade fan used in the indoor blower of Fig. 1, and the third factor is FIG. 4 is a characteristic diagram showing the aerodynamic performance of the indoor blower, and FIG. 4 is a schematic diagram showing the refrigeration cycle of a conventional heat pump air conditioner. 1... Compressor, 2... Four-way switching valve, 3
... Outdoor heat exchanger, 4 ... Pressure reducing device (capillary tube), 6 ... Indoor heat exchanger, 7 ...
... Outdoor blower, 9... Frost detection section, 10
...Frost formation detector, 12...Indoor blower, 13...Multi-blade fan, 14...
Single phase motor, 16...Defrosting control device.

Claims (1)

[Claims] A compressor, a four-way switching valve, an outdoor heat exchanger, a pressure reducing device, an indoor heat exchanger, etc. are connected in sequence, and an outdoor heat exchanger is provided corresponding to the outdoor heat exchanger. A frosting detector in which an indoor blower composed of a single-phase motor and a multi-blade fan is installed in correspondence with a blower and the indoor heat exchanger, and a detection unit is installed near the outdoor heat exchanger. and a defrosting control device that stops the outdoor blower, reverses the rotational direction of the indoor blower, and switches the four-way switching valve in conjunction with the detection operation of the arrival detector. Heat pump air conditioner.