JPS6360306B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air conditioner having a heat pump type refrigeration cycle mainly consisting of a compressor.

Generally, in this type of air conditioner, cooling operation and heating operation can be selectively performed by switching the flow direction of refrigerant discharged from the compressor using a refrigerant switching valve, such as a four-way valve. It's becoming like that. By the way, in such an air conditioner, when the load is high, the refrigeration cycle becomes overloaded, and the temperature of the refrigerant sucked from the evaporator to the compressor rises, which causes deterioration of the refrigerant. Moreover, the temperature of the windings inside the compressor increases significantly, which has an adverse effect on the windings. In order to solve this problem, there are some devices in which the low-temperature refrigerant that is about to be supplied to the evaporator is bypassed to the suction side of the compressor. However, in this case, simply bypassing the refrigerant may lead to a decrease in the operating capacity, that is, the cooling capacity or the heating capacity, depending on the load condition.

Further, in such an air conditioner, when heating operation is performed, if the outdoor heat exchanger that acts as an evaporator becomes frosted, the heating capacity will be reduced. Therefore, during heating operation, the flow direction of the refrigerant is reversed using a four-way valve depending on the temperature of the outdoor heat exchanger, and the outdoor heat exchanger acts as a condenser, thereby defrosting the outdoor heat exchanger. In addition, in order to suppress the influence of the cooling effect accompanying this defrosting, there is a system in which the rotation of the fan relative to the outdoor heat exchanger is stopped. However, for example, in an air-cooled heat pump chiller, the outdoor heat exchanger has two or more outside air suction surfaces, and the heat exchanger is divided and arranged for each surface, and the refrigerant is distributed to each heat exchanger. In the case where the heat exchanger is made to flow, each heat exchanger faces the sun, shade, or snow depending on the installation location, and the load on each heat exchanger may differ. That is, in the case of such an air conditioner, if defrosting is performed according to the temperature of a surface with little frost formation, residual frost formation will occur on other surfaces. On the other hand, if defrosting is performed according to the temperature of a surface with a large amount of frost, other surfaces will be defrosted excessively. Moreover, in this case, since the rotation of the fan for the outdoor heat exchanger has stopped, the discharge pressure of the compressor increases, and the protection device (high pressure switch) is activated, stopping the operation of the refrigeration cycle every time the defrost is carried out. This causes the inconvenience of doing so.

This invention was made in view of the above-mentioned circumstances, and its purpose is to reliably prevent the temperature rise of the refrigerant without causing a decrease in the operating capacity, and also to prevent the refrigerant from operating during defrosting. The purpose of the present invention is to provide an air conditioner that is highly reliable and practical and can eliminate inconveniences such as stopping of the air conditioner, and enables stable operation.

An embodiment of the present invention will be described below with reference to the drawings. In FIGS. 1 and 2, 1 is the main body of an air-cooled heat pump type chiller, and on both sides of the upper surface there are first heat exchangers such as air heat exchangers 2a and 2b.
are arranged to face each other, and a blower, such as a propeller fan 3, for circulating outdoor air to the air heat exchangers 2a and 2b is provided in the center.
On the other hand, 5 is a compressor equipped with a drive motor, 6 is a four-way valve, 7 is a heating expansion valve, 8 is a cooling expansion valve,
9 and 10 are check valves, and 11 is a second heat exchanger such as a water heat exchanger, and these compressor 5, four-way valve 6, expansion valves 7 and 8, check valves 9 and 10, and water heat exchanger 11 are sequentially connected to form a heat pump type refrigeration cycle. The water heat exchanger 11 includes:
Although not shown, a water pipe is provided, and this water pipe is connected to a fan coil installed indoors (not shown).
is communicated with. In this way, when cooling or heating is performed by switching the four-way valve 6, the water in the water pipes of the water heat exchanger 11 is cooled or warmed, and this water is circulated through the fan coil to cool the room. Or heating is available. And the air heat exchanger 2
A communicating portion between a and 2b and the water heat exchanger 11, for example a pipe line A connecting the expansion valve 7 and the expansion valve 8, is communicated via the refrigerant pipe 12 to the refrigerant absorption side of the compressor. That is, the refrigerant pipe 12 constitutes a refrigerant bypass path that bypasses the refrigerant in the communication portion between the air heat exchangers 2 a and 2 b and the water heat exchanger 11 to the refrigerant suction side of the compressor 5 . In this case, the refrigerant pipe 12 is provided with a valve, for example a two-way valve 13 and a capillary tube 14. Furthermore, the pipe A is provided with a refrigerant pressure detector 15.

FIG. 3 shows the control circuit. Between the bus lines RT connected to a control power source (not shown), there is an operation stop switch (automatically reset type normally closed contact) 20, an operation start switch (automatically reset type normally open contact) 21, and a cooling/heating operation selector switch. 22, a switching contact 23 of a relay 28, which will be described later, a relay 24, and a protection switch (normally closed contact of manual return type) 25 are connected in sequence. When the changeover switch 22 is set to "cooling", the movable contact 22 ₁ and the fixed contact 22 ₂ are closed, and when it is set to "heating", the movable contact 22 ₁ and the fixed contact 22 ₃ are closed. It is something that closes the gap. Further, the protection switch 25 opens when the refrigerant discharge pressure of the compressor 5 reaches a set value. The normally open contact 24a of the relay 24 is connected in parallel to the operation start switch 21.

Further, the relay 24 is connected to the relay 24 via the output switch 15a of the refrigerant pressure detector 15.
6 are connected in parallel. Further, one end of a relay 27 is connected to the connection point between the fixed contact 22 ₃ of the changeover switch 22 and the normally open fixed contact 23a of the changeover contact 23, and the other end of the relay 27 connected to the connection point. A relay 28 is connected in parallel to the relay 27 via the normally open contact 27a of the relay 27. Furthermore, one end of a timer motor 29 is connected to one end of the relay 27, and the other end of the timer motor 29 is connected to a connection point between the relay 28 and the contact 27a. The timer motor 29 constitutes a timer switch 31 with a switching contact 30 that responds to the timer motor 29, and the switching contact 30 switches between the movable contact 30 ₁ and the defrosting side fixed contact 30 ₂ and heating at fixed time intervals. It is designed to switch with respect to the side fixed contact ₃₀₃ . Furthermore, one end of a relay 32 is connected to one end of the relay 27, and the other end of this relay 32 is connected to the fixed contact ₃₀₂ . Further, one end of the electromagnetic coil 6l of the four-way valve 6 is connected to one end of the relay 27, and the other end of this coil 6l is connected to the movable contact ₃₀₁ of the switching contact 30. A defrosting thermoswitch (normally closed type) 33, a relay 34, and a normally open contact 32a of the relay 32 are connected in parallel between the movable contact ₃₀₁ and the fixed contact ₃₀₃ of the switching contact 30, respectively. There is. The thermo switch 33 is a second
This corresponds to the temperature of the refrigerant in pipe B in the refrigeration cycle shown in the figure.

Further, one end of the electromagnetic coil 13l of the two-way valve 13 is connected to the connection point between the operation start switch 21 and the changeover switch 22 via the normally open contact _26a1 of the relay 26, and the other end of the electromagnetic coil 13l of the two-way valve 13 is connected One end is connected to the other end of the relay 27 mentioned above. Furthermore, the drive motor for the propeller fan 3 is connected to the connection point between the operation start switch 21 and the changeover switch 22 via a normally closed contact 34b of the relay 34 and a normally open contact _26a2 of the relay 26 in parallel. One end of an electromagnetic contactor 35 for controlling the opening and closing of an energizing path to (not shown) is connected, and the other end of this contactor 35 is connected to the other end of the relay 27. A compressor motor (not shown) of the compressor 5 is connected to the connection point between the operation start switch 21 and the changeover switch 22 through a changeover contact 36 of the relay 28 and a cold/hot water thermoswitch 37 in series. ) is connected to one end of an electromagnetic contactor 38 that controls opening and closing of the energizing path, and the other end of this contactor 38 is connected to the other end of the relay 27 . The hot/cold water thermoswitch 37 closes between the movable contact 37 ₁ and the cooling side fixed contact 37 ₂ when the temperature of the water in the water pipe of the water heat exchanger 5 is high, and is movable when the water temperature is low. The contact 37 ₁ and the heating side fixed contact 37 ₃ are closed.

Next, the operation in the above configuration will be explained. First, when the temperature of the water in the water pipes of the water heat exchanger 11 is high, such as in summer, the hot and cold water thermoswitch 3
The movable contact 37 ₁ and the fixed contact 37 ₂ of No. 7 are in a closed state. Then, the cooling operation is set with the changeover switch 22 (the movable contact 22 ₁ and the fixed contact 22 ₂ are closed), and the operation start switch 21 is turned on. Then, the relay 24 is energized and its contact 2
A self-holding circuit is constructed by closing 4a.
Then, the electromagnetic contactors 35 and 38 are each excited, and the propeller fan 3 and compressor 5 are respectively operated. In this way, the refrigerant discharged from the compressor 5 passes through the four-way valve 6 to the air heat exchangers 2a and 2.
b, where heat is taken away by the air circulating by the fan 3 and condensed, that is, liquefied. The refrigerant liquefied in the air heat exchangers 2 a and 2 b is supplied to the expansion valve 8 via the check valve 9 , is depressurized by the expansion valve 8 , and is supplied to the water heat exchanger 11 . In this water heat exchanger 11, the refrigerant takes heat from the water in the water pipes and evaporates, that is, vaporizes. Therefore, the water in the water pipes of the water heat exchanger 11 is cooled, and the cooled water circulates through a fan coil (not shown) to cool the room. By the way, during such a cooling operation, when the load is high, that is, when the temperature of the water in the water pipes of the water heat exchanger 11 is extremely high, the refrigeration cycle becomes overloaded and the water is sucked into the compressor 5. The temperature of the refrigerant will rise. At this time, the refrigerant pressure in the pipe A is also increasing, and when the pressure reaches the set value, the output switch 15a of the detector 15 is activated.
becomes a closed state. Then, the relay 26 is energized, and its contacts 26a ₁ and 26a ₂ are closed, respectively.
By closing the contact 26a ₁ , the coil 13l
is excited. In other words, the two-way valve 13 is opened, and the low-temperature refrigerant (part of the liquid refrigerant) output from the air heat exchangers 2a and 2b is bypassed to the refrigerant suction side of the compressor 5 via the refrigerant pipe 12. Ru. Therefore, the temperature of the refrigerant sucked into the compressor 5 can be lowered.

In addition, when the temperature of the water in the water pipes of the water heat exchanger 11 is low, such as in winter, the hot and cold water thermoswitch 37
The movable contact 37 ₁ and the fixed contact 37 ₂ are in a closed state. Then, the heating operation is set with the changeover switch 22 (the movable contact 22 ₁ and the fixed contact 22 ₃ are closed), and the operation start switch 21 is turned on.
Then, the relay 27 is energized and its contact 27a
The relay 28 is energized by the closing of the relay 28. As a result, the movable contact 23c and the fixed contact 23a of the switching contact 23 are closed by the excitation of the relay 28,
This causes the relay 24 to be energized. In other words, a self-holding circuit is constructed by closing the contact 24a. Further, due to the excitation of the relay 28, the movable contact 36c and the fixed contact 36a of the switching contact 36 are closed, the contactor 38 is energized, and the compressor 5 is operated. Further, at this time, the coil 6l is energized by closing the contact 27a, and the four-way valve 6 is switched. Further, the timer motor 29 operates. In this case, since the defrosting thermoswitch 33 remains closed, the relay 34 is not energized, and the contactor 35 is thereby energized and the fan 3 is operated. In this way, the refrigerant discharged from the compressor 5 is
is supplied to the water heat exchanger 11 via the four-way valve 6,
Heat is taken away by the water in the water pipes of the water heat exchanger 11 and the water is condensed or liquefied. The liquefied refrigerant is then supplied to the expansion valve 7 via the check valve 10, reduced in pressure by the expansion valve 7, and supplied to the air heat exchangers 2a, 2b. This air heat exchanger 2
In a and 2b, the refrigerant takes heat from the circulating air by the fan 3 and evaporates, that is, vaporizes. Therefore, the water in the water pipes of the water heat exchanger 11 is heated,
The heated water circulates through a fan coil (not shown) to heat the room. By the way, during such a heating operation, when the load is high, that is, when the temperature of the water in the water pipes of the water heat exchanger 11 is extremely high, the refrigeration cycle becomes overloaded and the water is sucked into the compressor 5. The temperature of the refrigerant will rise. However, at this time, since the temperature of the water in the water pipes of the water heat exchanger 11 is extremely high, the condensation effect of the refrigerant in the water heat exchanger 11 becomes insufficient, and the refrigerant pressure in the refrigeration cycle increases overall. , the refrigerant pressure in pipe A is also increasing, and when the pressure reaches the set value, detector 1
5, the two-way valve 13 is opened.
The refrigerant in a low temperature state (part of the liquid refrigerant) output from the water heat exchanger 11 is passed through the refrigerant pipe 12 to the compressor 5.
is bypassed to the refrigerant suction side. Therefore, the temperature of the refrigerant sucked into the compressor 5 can be lowered.

Further, during such a heating operation, the switching contact 30 of the timer switch 31 changes from the movable contact 30 ₁ to the fixed contacts 30 ₂ , 30 periodically, that is, at regular intervals.
₃ , but the defrosting thermo switch 3
As long as the coil 3 remains closed, the excitation state of the coil 6l continues. Thereafter, when the air heat exchangers 2a and 2b become frosted, the defrosting thermoswitch 33 is opened (when defrosting is required). Then, when the movable contact 30 ₁ and the fixed contact 30 ₂ of the switching contact 30 are closed and the defrosting operation is set,
A voltage is applied to the series body of the coil 6l and the relay 34, but since the impedance of the relay 34 is much larger than that of the coil 6l, the relay 34 is energized and the coil 6l is no longer energized. Therefore, the contact 34b is opened and the excitation state of the contactor 35 is released. In other words, the operation of the fan 3 is stopped. Further, the four-way valve 6 is switched, the refrigeration cycle changes from the heating cycle to the defrosting cycle, and defrosting is performed for a certain period of time based on the timer switch 31. In this way, defrosting is performed, and for example, even if the defrosting of the air heat exchanger 2a facing the shaded side is not yet completed, the defrosting of the other air heat exchanger 2b facing the sunny side is completed. , when the pressure in the conduit A increases and reaches the set value, the output switch 15a of the detector 15 closes, and the relay 26 is energized to close the contact _26a2 . In other words, fan 3 operates. As a result, the air heat exchangers 2a and 2b are cooled, and the two-way valve 13 is further cooled.
The refrigerant pressure in the conduit A decreases due to the addition of refrigerant bypass to the compressor 5 due to the opening of the output switch 15a (based on the closing of the output switch 15a). In this manner, when the refrigerant pressure in the conduit A becomes equal to or less than the set value, the output switch 15a is reset and the operation of the fan 3 is stopped. In this case, since the refrigerant pressure when the output switch 15a closes is lower than the refrigerant pressure when the protection switch 25 opens, the operation will not stop during defrosting. Then, when the defrosting thermoswitch 33 returns to normal operation, heating operation resumes.

In addition, in the above embodiment, the air heat exchanger 2
The position of the pipeline where the bypass path is formed with respect to the communication portion between a, 2b and the water heat exchanger 11 may be as shown in FIGS. 4 and 5. In this case, FIG. 4 focuses on the cooling operation, and FIG. 5 focuses on the heating operation.

Further, although the above embodiment describes an air-cooled heat pump type chiller, the present invention can be similarly implemented in an air conditioner in which the water heat exchanger is replaced with an indoor air heat exchanger. In addition, the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

As described above, according to the present invention, the compressor,
A first heat exchanger that is divided into a plurality of parts, and a second heat exchanger that is divided into a plurality of parts.
In an air conditioner, the air conditioner has a heat pump refrigeration cycle in which heat exchangers and the like are sequentially connected, and a blower that circulates air to the first heat exchanger. A refrigerant bypass passage that bypasses the refrigerant in the communication portion with the heat exchanger to the refrigerant suction side of the compressor, a valve provided on the refrigerant bypass passage, and the first heat exchanger and the second heat exchanger. a refrigerant pressure detector for detecting the refrigerant pressure in the communication section; a means for controlling the opening and closing of the valve according to the pressure detected by the refrigerant pressure detector; a means for operating the blower during cooling and heating operations; means for defrosting the first heat exchanger by switching the heating cycle to a defrosting cycle periodically or as needed; Since a means for operating the blower only at certain times is provided, it is possible to reliably prevent a rise in temperature of the refrigerant without causing a decrease in operating capacity, and also to prevent the operation from stopping during defrosting. It is possible to provide an air conditioner with excellent reliability and practicality that can eliminate the inconvenience and enable stable operation.

[Brief explanation of the drawing]

The drawings show one embodiment of the invention.
The figure is a configuration diagram showing the arrangement of the air heat exchanger of an air-cooled heat pump chiller, Figure 2 is a configuration diagram of the refrigeration cycle, Figure 3 is a control circuit, and Figures 4 and 5 are configuration diagrams showing modified examples. It is. 1...Chiller body, 2a, 2b...1st heat exchanger (air heat exchanger), 3...Blower (propeller fan), 5...Compressor, 11...2nd heat exchanger (water heat exchanger) ), 12...refrigerant bypass (refrigerant pipe),
13...Valve (two-way valve).

Claims (1)

[Claims] 1. A heat pump type refrigeration cycle in which a compressor, a first heat exchanger divided into a plurality of parts, a second heat exchanger, etc. are connected in sequence, and air is circulated to the first heat exchanger. In an air conditioner equipped with an air blower, the refrigerant bypass path bypasses the refrigerant in the communication section between the first heat exchanger and the second heat exchanger to the refrigerant suction side of the compressor, and the refrigerant bypass path is provided. a refrigerant pressure detector that detects refrigerant pressure in a communication portion between the first heat exchanger and the second heat exchanger, and a refrigerant pressure detector that controls opening and closing of the valve in accordance with the detected pressure of the refrigerant pressure detector. means for operating the blower during cooling and heating operations; and means for defrosting the first heat exchanger by periodically or as needed switching the heating cycle to a defrosting cycle during heating operations; and means for operating the blower only when the pressure detected by the refrigerant pressure detector is equal to or higher than a set value during defrosting.