JPS6022294Y2 - Heat pump air conditioner - Google Patents

Description

[Detailed description of the invention] This invention relates to a large-sized heat pump type air conditioner when performing defrosting operation of an air heat source side heat exchanger using a reverse cycle method. To provide an improved device which performs a defrosting operation to ensure that no frost remains on any of the exchangers, and also ensures the start of the defrosting operation without delay.

Below, one embodiment of the present invention will be explained based on the drawings.
In the refrigerant circuit diagram shown in the figure, 1 is a compressor, 2 is a four-way valve that switches the refrigerant flow path to a forward and reverse cycle during heating and cooling defrosting operations,
3 is a header, 4 is a unit heat exchanger 4a, 4bg 4eg 4 installed outdoors and having multiple rows (5 rows in one example).
d* Air heat source side heat exchanger consisting of 4e, 5a, 5b
, 5c, 5d, and 5e are branch pipes connected to these unit heat exchangers, 6 is a flow divider that collects these branch pipes, and 7 is a branch pipe connected to these unit heat exchangers.
8 is a refrigerant pressure reducing element such as an expansion valve or a capillary tube, 8 is a subcooling coil for anti-freezing disposed at the bottom of the air heat source side heat exchanger 4, 9 is a user side heat exchanger installed indoors, 10 and 11 are check valves, and these devices constitute a heat pump type refrigerant circuit.

Reference numeral 12 denotes a blower that introduces outside air from the front of the air heat source side heat exchanger 4 and discharges it upward as shown by the solid line arrow, and a part of the discharged air is short-circuited as shown by the dashed-dotted line arrow and returns to the air heat source side heat exchanger 4. 4, the heat exchange efficiency of this unit heat exchanger 4a is lower than that of the other unit heat exchangers 4b, 4C, 4dt 4e, and If only 5 rows of unit heat exchangers are formed using heat transfer tubes 13 with the same number of passes, the number of passes will be small compared to the amount of refrigerant circulation, and if 6 rows of unit heat exchangers are formed, it will be too large compared to the amount of refrigerant circulation. In view of this, only the unit heat exchanger 4a has an increased number of passes of the heat exchanger tubes 13.

Furthermore, as described above, since the outside air is sucked in and discharged upward from the front of the air heat source side heat exchanger 4, the lowermost unit heat exchanger 4e, which is farthest from the blower 12, has the slowest air blowing speed and inferior heat exchange efficiency. However, during the heating operation cycle, compressor 1 - four-way valve 2 - user side heat exchanger 9 - subcooling coil 8 - check valve 10 -
Refrigerant pressure reducing element 7 - Flow divider 6 - Each branch pipe 5a, 5b, 5
c, 5d, 5e - Each unit heat exchanger 4at 4bt 4ct 4dt 4e - Header 3 of air heat source side heat exchanger 4
- Four-way valve 2 - The lowermost unit heat exchanger 4 adjacent to the compressor 1 and the subcooling coil 8 in which refrigerant circulates and high-pressure liquid refrigerant flows.
Since e is heated, the heat exchange efficiency improves, so the unit heat exchanger 4b, which is located at the upper stage and has the next slowest wind speed, has the lowest heat exchange efficiency.

From the above points, as an embodiment of the present invention, we focused on the unit heat exchanger 4a with a large number of passes and the unit heat exchanger 4b with the lowest heat exchange efficiency, and in both cases, at least two unit heat exchangers with poor heat exchange efficiency. Each branch pipe 5a, 5b which becomes the refrigerant inflow side during heating and the refrigerant outflow side during defrosting of the container 4at4b is provided with a temperature sensing cylinder of the defrosting thermometer 15 covered with an inclusion 14 for temperature sensing delay such as a polyethylene resin tube. 16 are attached together at the same time.

Figure 2 shows the defrosting thermometer 15 mentioned above, the motor electromagnetic coil CM for the compressor 1, and the motor FM four-way valve 2 for the outdoor blower 12.
An electrical circuit diagram showing the circuit connections of the electromagnetic coil SV, etc.
DT is a defrosting timer that operates while the timer is energized, and rDl is switched on from the a terminal after 6 minutes when the timer is energized, and is held closed when the timer is not energized, and a is turned on in a short time of about 1 minute when the timer is energized. rD2 is a timer relay contact which is turned on when the timer DT is energized and is automatically opened after integration has elapsed; Relay contact that is closed when energized, r□ is a relay contact that is closed when one relay coil R□ is energized, r2
Similarly, 17 is an operation switch, 18 is a cooling switch that is opened during cooling, and 19 is a heating switch that is closed during heating.

The structure is as described above. During heating operation, when the operation switch 17 is turned on with both the air conditioning and heating switches 18 and 19 turned on, the motor electromagnetic coil CM for the compressor 1, the motor FM for the outdoor blower 12, and the electromagnetic coil for the four-way valve 2 are activated. Coil S■ is energized to form the above-mentioned heating cycle and heat the room.

At the same time, the defrost timer DT is energized through the relay contact rc, which is turned on by the excitation of the electromagnetic coil CM, and the relay contact rD, which is turned on to the a terminal, and after 6 hours have passed, it is switched to the b terminal and reset and turned on. When the defrosting thermometer 15 is opened, the defrosting timer DT is de-energized and the timer operation is stopped, and the terminal b is kept connected to the defrosting timer DT.

During such winter heating operation, when the outside air temperature decreases to around 0°C, frost begins to form on the unit heat exchangers 4a and 4b of the air heat source side heat exchanger 4, which has poor heat exchange efficiency, and when a predetermined amount of frost has formed, the outside air The heat exchange efficiency with the unit heat exchanger 4a * 4b decreases rapidly, the low pressure decreases, and along with this, the branch pipes 5a, 5 of the unit heat exchanger 4a * 4b
The temperature of b begins to decrease.

In such a case, it is almost impossible for the temperature of the branch pipes 5a and 5b to drop to the same temperature at the same time, depending on the installation condition of the outdoor unit containing the air heat source side heat exchanger 4 and the strong and weak wind conditions of the outside air flow. For example, the temperature of the branch pipe 5a is 17°C.
At this time, the temperature of the other branch pipe 5b varies by 15°C, and when this average temperature reaches -6°C, the defrosting thermometer 15 is turned on.

As will be described later, the temperature sensing cylinder 16 of the defrosting thermometer 15 is delayed in temperature sensing by an inclusion 14 that dulls the temperature sensing by 1°C in order to prevent frost from remaining after the defrosting is completed. The set temperature for turning on the frost thermometer 15 is -5°C.

On the other hand, the defrost timer DT is de-energized after 6 hours and is in a standby state where the relay contact rD is connected to the b terminal and held, so when the defrost thermometer 15 is turned on as described above, the relay winding R1 is excited and this relay contact r1 is closed.

As a result, the defrost timer DT starts operating, relay contact rD2 is closed, and relay winding R2 is energized, so that this relay contact r2 is closed and self-holding, and this relay reverse contact r2 is opened. Then, the electromagnetic coil SV is demagnetized, the four-way valve 2 is reversed, and defrosting operation using the reverse cycle method is started.

In this way, the relay contact rD□ is connected to the b terminal and held, and the defrost timer DT is kept on standby in the stopped state.
By adopting the inclusion 14, even if frost detection is delayed, defrosting will start almost at the same time as the defrost thermostat 15 is turned on, and due to the delay in frost detection, the defrost timer DT will pass by and the defrost will continue for a predetermined period of time. This solves the problem of defrosting operation not starting until the time has elapsed.

At the same time, when the defrosting timer DT starts operating, the relay contact rD is turned on and returned to the a terminal after 1 minute, returning to the original state, and the relay contact rD2 is turned on, and this relay contact rD2 starts defrosting as described later. In order to forcibly terminate the operation, it will be released after integration after being turned on.

When the four-way valve 2 is reversed, the high-temperature, high-pressure discharge refrigerant gas from the compressor 1 is transferred from the header 3 to each unit heat exchanger 4a, 4b, 4 of the air heat source side heat exchanger 4 through the reversed four-way valve 2.
Defrosting is started by flowing into C, 4d, and 4e, and the condensed liquid refrigerant that flows out is transferred to each branch pipe 5at 5bt 5eg 5d?
5e - flow divider 6 - refrigerant pressure reducing element 7 - check valve 11 - utilization side heat exchanger 9 - four-way valve 2 - compressor 1 to form a defrosting cycle for circulation.

During such defrosting operation, the unit heat exchanger 4a which started frosting the earliest and the temperature of the branch pipe 5a decreased to 17°C has the largest amount of frost, and the other unit heat exchangers 4c.

Including unit heat exchangers 4d and 4e, the defrosting time is longer than that of the unit heat exchanger 4b, and ultimately the temperature is 10°C, which is necessary to bring the unit heat exchanger 4a into a complete defrost state with no frost residue. The defrosting operation will be performed until the temperature of the branch pipe 5a reaches 90°C, but since the branch pipe 5a is connected to the other branch pipe 5b as described above, for example, the temperature of the branch pipe 5a will decrease to 9. Although the temperature of the other branch pipe 5b has risen to 11'C even though the temperature has only risen to 11'C, if this average temperature of 10C is sensed and defrosting is terminated, the unit heat exchanger 4a is returned to heating operation with the remaining frost remaining.

Eliminating this problem is the most distinctive feature of the present invention.As mentioned above, by covering the temperature sensing tube 16 with the temperature sensing delaying inclusion 14, the temperature sensing is dulled by 1 degree Celsius, and the average temperature is reduced. 11°C, that is, the temperature of one branch pipe 5a is 1.
0℃, and when the temperature of the other branch pipe 5b rises to 12'C, the defrosting thermometer 15 is opened and the relay coils R□, R
2 is demagnetized and this relay contact r□ is opened, and at the same time, the relay reverse contact r2' is closed and the four-way valve 2 is switched to the heating cycle side by energizing the electromagnetic coil SV, and the relay contact r2 is opened.

At this time, the defrost timer DT is connected to one of these relay contacts r.
Since the transmission is continued through D1, it continues to operate, and even if the defrosting operation is performed for m minutes, the branch pipes 5a,
If the average temperature of 5b does not rise to 10℃, the other relay contact rD2 is opened to forcefully terminate the defrosting operation, but this is an extremely rare case, and normally
Defrosting usually takes about a minute to complete.

In addition, the inclusion 14 for temperature sensing delay is attached to the temperature sensing cylinder 1 as described above.
Instead of covering 6, the branch pipes 5a and 5b may be covered. Also, if there is a unit heat exchanger 5C, 5d, or 5e that has particularly poor heat exchange efficiency, this branch pipe may be used as a branch pipe. 5a and 5b may be attached together with the temperature-sensitive cylinder 16 at the same time.

Further, by changing the thickness of the inclusion 14 as necessary, it is possible to adjust the degree of temperature-sensitive delay depending on the usage conditions.

Next, during the cooling operation, if both the air conditioning and heating switches 18 and 19 are left open, only the motor electromagnetic coil CM for the compressor 1 and the motor FM for the blower 12 are energized, and the cooling operation is performed.

The refrigerant flow during the cooling cycle is the same as that in the defrosting cycle described above, so a description thereof will be omitted.

As detailed above, the proposed device targets large air heat source side heat exchangers that have at least two or more unit heat exchangers with poor heat exchange efficiency, and is designed to ensure that no frost remains on any of the unit heat exchangers. Since the defrost sensor's thermosensor tube is attached via an inclusion for temperature sensing delay, the defrosting operation can be completed reliably and completely. In order to eliminate the drawback that the defrost detection becomes slow and the defrost timer passes by without the defrost thermometer not operating, and the defrosting operation does not start until one cycle of 6 hours has elapsed, the defrost is activated at the same time as the defrost thermostat is activated. Since the defrost timer is placed on standby in a stopped state, the defrost operation can be started without delay, and there is no need to individually adjust the temperature setting of the defrost thermometer itself, so it is a standard commercially available product. It is extremely useful in practical terms, as it is highly versatile and can be used as is.

[Brief explanation of the drawing]

FIG. 1 is a refrigerant circuit diagram showing one embodiment of the heat pump air conditioner according to the present invention, and FIG. 2 is a main electrical circuit diagram showing the same embodiment. 4...Air heat source side heat exchanger, 4a, 4b,
4c, 4d, 4e@@@-66 unit heat exchanger, 5av5b*5c, 5d, 5e...Diversion piping, 14...Inclusion, 15... Defrosting thermometer, 16...Temperature tube, DT...
Defrost timer.

Claims (1)

[Scope of utility model registration request] A refrigerant piping location that becomes the refrigerant inflow side during heating and the refrigerant outflow side during defrosting of at least two or more unit heat exchangers with poor heat exchange efficiency among the air heat source side heat exchangers consisting of a plurality of unit heat exchangers. After being energized for a predetermined period of time via the defrosting sensor's temperature-sensing tube, the timer relay contact, and the a-terminal, which are attached via a temperature-sensing delay intervention, the relay contact is transferred from the a-terminal to the b-terminal. A defrosting timer that is switched on and held at this B terminal, two relay windings that are connected to this B terminal and energized when the defrosting circuit is turned on, and a heating when one of the relay windings is energized. A valve electromagnetic coil that switches from a cycle to a defrost cycle, and this a that energizes the defrost timer when the other relay winding is energized and returns the timer relay contact to the a terminal.
1. A human-pump air conditioner comprising: a relay contact for terminal short-circuit; and a self-holding relay contact for short-circuiting the terminal when the other relay winding is energized.