Heat exchange ventilation system

Abstract

To provide a heat exchange type ventilation device capable of rapidly activating a compressor.SOLUTION: A heat exchange type ventilation device includes: an air supply fan supplying air outside a space as a supply air flow into the space; a dehumidifying part dehumidifying the supply air flow by utilizing a refrigeration cycle connected to a compressor, a condenser, an expander and a vaporizer in this order; a sensor-less DC motor for driving the compressor; an upstream temperature detecting part detecting an upstream temperature in the refrigeration cycle of the compressor; a downstream temperature detecting part detecting a downstream temperature in the refrigeration cycle of the compressor; and a control part controlling the sensor-less DC motor. When driving the compressor, the control part starts an operation of the sensor-less DC motor when a temperature difference between the downstream temperature and the upstream temperature is equal or lower than a threshold value, and starts the operation of the sensor-less DC motor after waiting until the temperature difference becomes equal or lower than the threshold value when the temperature difference is larger than the threshold value. Such a mechanism solves the problem stated above.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a heat exchange type ventilation device. [Background technology]

[0002] 2. Description of the Related Art A refrigeration cycle mounted in an air conditioner is conventionally known (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 57-006269 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, a heat exchange type ventilator that exchanges heat between an intake airflow and an exhaust airflow during ventilation has been known as a device that can ventilate without impairing the cooling or heating effect. In addition, due to the effects of global warming and the improvement of airtightness of houses in recent years, there is concern that indoor heat and humidity exhaust is insufficient, making the indoor temperature and humidity high, especially in the Japanese summer, and thus impairing indoor comfort for residents. In order to improve indoor comfort in the Japanese summer, it is particularly important to reduce indoor humidity. Therefore, a heat exchange type ventilator with improved dehumidification performance was developed by combining a dehumidification function using a refrigeration cycle with a heat exchange type ventilator.

[0005] In a conventional refrigeration cycle, a compressor, a condenser, an expander, and an evaporator are connected in a ring shape by refrigerant piping, and the refrigerant pressure is controlled by the compressor and the expander while the condenser exchanges heat for heating and the evaporator exchanges heat for cooling. If the compressor stops during operation due to some reason, such as a momentary power outage, the refrigerant pressure is high on the discharge side of the compressor and low on the suction side of the compressor. If the compressor is started in a state where there is a pressure difference between the refrigerant pressure on the discharge side of the compressor and the refrigerant pressure on the suction side of the compressor, the compressor must start while being subjected to the pressure difference, and start-up may fail.

[0006] To ensure the compressor starts, the refrigerant pressure on the discharge side of the compressor and the refrigerant pressure on the suction side of the compressor must be approximately the same (hereafter referred to as pressure equalization), but it takes time for the refrigerant in the refrigerant piping to flow from the high-pressure side to the low-pressure side and be pressure equalized. The time required for this pressure equalization (hereafter referred to as pressure equalization time) becomes longer the greater the pressure difference between the refrigerant pressure on the discharge side of the compressor and the refrigerant pressure on the suction side of the compressor.

[0007] This pressure difference depends on the compressor rotation speed, outdoor temperature and indoor temperature and humidity immediately before the compressor stops operating. For example, when the outdoor temperature and humidity are high and the indoor temperature and humidity are high during cooling, the operating load for cooling is high and the compressor rotation speed increases, and if the compressor stops in this state, it stops with the pressure difference remaining large. In other words, the pressure equalization time becomes long. Conversely, when the operating load for cooling is low, the compressor rotation speed becomes low, and if the compressor stops in this state, it stops with the pressure difference remaining small. In other words, the pressure equalization time becomes short.

[0008] In order to start the compressor promptly after it has stopped operating, the pressure equalization time may be set according to the compressor speed, outdoor temperature and humidity, and indoor temperature and humidity immediately before the compressor stops operating. However, since there are a wide variety of combination patterns of outdoor temperature and humidity, indoor temperature and humidity, and compressor speed immediately before the compressor stops operating, it is not realistic to set individual pressure equalization times corresponding to all combination patterns. Therefore, the pressure equalization time is generally set to a time required to reliably start the compressor. In other words, the pressure equalization time is generally set to the longest pressure equalization time that reliably achieves pressure equalization, regardless of the outdoor and indoor temperature and humidity conditions or the compressor speed immediately before the compressor stops operating.

[0009] However, if the pressure equalization time is set to the longest time necessary to reliably achieve pressure equalization, the compressor will be in a state of waiting to be started even when it is in a state where it can be started, which creates the problem that the compressor cannot be started promptly.

[0010] SUMMARY OF THE PRESENT INVETION The present invention is devised to solve the above-mentioned problems in the conventional art, and has an object to provide a heat exchange type ventilator capable of quickly starting up a compressor. [Means for solving the problem]

[0011] To achieve this object, the heat exchange type ventilation device according to the present invention includes a supply air fan that supplies air from outside the space as a supply air flow through a supply air duct into the space, a dehumidification unit that uses a refrigeration cycle in which a compressor, a condenser, an expander, and an evaporator are connected in this order to dehumidify the supply air flow, a sensorless DC motor for driving the compressor, an upstream temperature detection unit that detects an upstream temperature, which is the temperature upstream of the refrigeration cycle of the compressor, a downstream temperature detection unit that detects a downstream temperature, which is the temperature downstream of the refrigeration cycle of the compressor, and a control unit that controls the timing of starting the operation of the sensorless DC motor, and when starting the compressor, if the temperature difference between the downstream temperature and the upstream temperature is equal to or less than a predetermined threshold, the control unit starts the operation of the sensorless DC motor, and if the temperature difference between the downstream temperature and the upstream temperature is greater than the predetermined threshold, the control unit waits until the temperature difference between the downstream temperature and the upstream temperature becomes equal to or less than the predetermined threshold, and then starts the operation of the sensorless DC motor. This achieves the intended object. Effect of the Invention

[0012] According to the present invention, it is possible to provide a heat exchange type ventilation device capable of quickly starting up a compressor. [Brief description of the drawings]

[0013] [Figure 1] 1 is a schematic diagram of a heat exchange type ventilation device according to an embodiment of the present invention. [Diagram 2] 2 is a schematic functional block diagram of a control unit and its peripheral parts according to the embodiment of the present invention; FIG. [Diagram 3] 5 is a flowchart showing a control process of a control unit according to the embodiment of the present invention. [Figure 4] FIG. 4 is a schematic diagram of a heat exchange type ventilation device according to a first modified example of the present invention. [Diagram 5] FIG. 11 is a schematic diagram of a heat-exchange type ventilation device according to a second modified example of the present invention, in which the air duct for the exhaust airflow is an exhaust air duct. [Figure 6] FIG. 11 is a schematic diagram of a heat exchange type ventilation device according to a second modified example of the present invention, in which the exhaust air duct is a bypass exhaust air duct. [Figure 7] FIG. 11 is a schematic functional block diagram of a control unit and its peripheral units according to a second modified example of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, the embodiments for carrying out the present invention will be described with reference to the drawings. However, the embodiments shown below are merely illustrative in order to embody the technical idea of ​​the present invention, and the present invention is not limited to the following. In particular, the materials, shapes, components, arrangements and relative arrangements of the components described in the embodiments are merely examples, and are not intended to limit the scope of the present invention thereto. In addition, in each drawing, substantially identical components are given the same reference numerals, and duplicated explanations are omitted or simplified.

[0015] (Embodiment) First, a heat exchange type ventilation device 1A according to an embodiment of the present invention will be described. Fig. 1 is a schematic diagram of the heat exchange type ventilation device 1A.

[0016] The heat exchange type ventilation device 1A is a ventilation device with a dehumidifying function that supplies and exhausts air to indoor spaces and can be installed in the ceiling, inside a side wall, or under the floor of a building, and has the function of exchanging heat when supplying and exhausting air.

[0017] The heat exchange ventilator 1A ventilates while exchanging heat between air exhausted from indoors to outdoors (exhaust air flow 13 described later) and air supplied from outdoors to indoors (intake air flow 12 described later), and also dehumidifies the intake air flow 12 as necessary using a dehumidification function and introduces it indoors. In other words, the heat exchange ventilator 1A not only ventilates, but also transfers the heat of the intake air flow 12 to the exhaust air flow 13 during ventilation, thereby suppressing unnecessary inflow of heat. Furthermore, it dehumidifies the intake air flow 12 to suppress an increase in the humidity of the air indoors (indoor relative humidity).

[0018] Here, the exhaust air flow 13 is a flow of air exhausted from indoors to outdoors. The exhaust air flow 13 is transported from indoors to the heat exchange type ventilation device 1A. The exhaust air flow 13 that has been heat exchanged with the intake air flow 12 by the heat exchange type ventilation device 1A is exhausted from the heat exchange type ventilation device 1A to outdoors.

[0019] The intake air flow 12 is a flow of air introduced from outdoors to indoors. The intake air flow 12 is transported from outdoors to the heat exchange type ventilation device 1A. The intake air flow 12, which has been heat exchanged with the exhaust air flow 13 by the heat exchange type ventilation device 1A, is dehumidified by the dehumidification function as necessary, and is introduced indoors.

[0020] The heat exchange type ventilation device 1A is a device that ventilates while exchanging heat between indoor air RA (exhaust air flow 13) and outdoor air OA (supply air flow 12).

[0021] Specifically, the heat exchange type ventilation device 1A includes a main body 2 as shown in FIG.

[0022] The main body 2 has a housing having a generally rectangular parallelepiped shape. An inside air port 5, an exhaust port 6, an outside air port 8, and an intake air port 9 are provided on a side surface of the main body 2.

[0023] The indoor air vent 5 is an intake port for taking in indoor air RA (exhaust air flow 13) into the heat exchanger type ventilation device 1A. The exhaust air vent 6 is an outlet port for discharging the exhaust air flow 13 from the heat exchanger type ventilation device 1A to the outdoors as exhaust air EA. The outdoor air vent 8 is an intake port for taking in outdoor air OA (supply air flow 12) into the heat exchanger type ventilation device 1A. The supply air vent 9 is an outlet port for discharging the supply air flow 12 from the heat exchanger type ventilation device 1A to the outdoors as supply air SA.

[0024] The main body 2 is provided therein with a heat exchange element 3 .

[0025] The heat exchange element 3 is a member for performing heat exchange between the exhaust air flow 13 and the intake air flow 12. The heat exchange may be sensible heat exchange, which exchanges temperature between the exhaust air flow 13 and the intake air flow 12, or total heat exchange, which performs both sensible heat exchange and latent heat exchange, which exchanges humidity between the exhaust air flow 13 and the intake air flow 12.

[0026] The heat exchange element 3 is a total heat exchange element formed of a heat transfer paper (heat transfer plate) based on cellulose fiber. However, the material is not limited to this. For example, a moisture-permeable resin film based on polyurethane or polyethylene terephthalate, or a paper material based on cellulose fiber, ceramic fiber, or glass fiber can be used as the heat transfer plate constituting the heat exchange element 3. In addition, the heat transfer plate constituting the heat exchange element 3 can be a thin sheet having heat conductivity and a property that gas cannot pass through. In this case, the heat exchange element 3 becomes a sensible heat exchange element.

[0027] Furthermore, an exhaust fan 4 and an intake fan 7 are provided inside the main body 2.

[0028] The exhaust fan 4 is a blower that takes in the exhaust air flow 13 from the inside air port 5 and expels it from the exhaust port 6. The supply air fan 7 is a blower that takes in the supply air flow 12 from the outside air port 8 and expels it from the supply air port 9.

[0029] Inside the main body 2, an exhaust air duct 10 that communicates the inside air port 5 and the exhaust air duct 6, and an intake air duct 11 that communicates the outside air port 8 and the intake air duct 9 are formed. The exhaust air flow 13 sucked in by the exhaust fan 4 passes through the heat exchange element 3, the exhaust fan 4, and the condenser 15 in the exhaust air duct 10, and is discharged from the exhaust air duct 6 to the outdoors. The intake air flow 12 sucked in by the intake air fan 7 passes through the heat exchange element 3, the intake air fan 7, and the evaporator 17 in the intake air duct 11, and is supplied to the indoors from the intake air duct 9. When performing heat exchange ventilation, the heat exchange type ventilator 1A operates the exhaust fan 4 and the intake air fan 7, and exchanges heat in the heat exchange element 3 between the exhaust air flow 13 flowing through the exhaust air duct 10 and the intake air flow 12 flowing through the intake air duct 11.

[0030] As a result, when ventilating, the heat exchanger type ventilation device 1A transfers the heat of the intake airflow 12 taken into the room to the exhaust airflow 13 discharged to the outside, suppressing the inflow of unnecessary heat. As a result, when ventilating in the Japanese summer, it is possible to suppress the rise in the indoor temperature due to air with a high outdoor temperature. Also, when ventilating, the heat exchanger type ventilation device 1A transfers the heat of the exhaust airflow 13 discharged to the outside to the intake airflow 12 taken into the room, suppressing the release of unnecessary heat and recovering heat indoors. As a result, when ventilating in the Japanese winter, it is possible to suppress the drop in the indoor temperature due to air with a low outdoor temperature.

[0031] Furthermore, the main body 2 is provided therein with a compressor 14, a condenser 15, an expander 16, and an evaporator 17. The compressor 14, the condenser 15, the expander 16, and the evaporator 17 are connected in this order in a ring shape by refrigerant piping 18 to form a refrigeration cycle, and the evaporator 17 serves as a dehumidifier and has a dehumidifying function of dehumidifying the intake air flow 12. The refrigerant piping 18 is made of metal.

[0032] The compressor 14 is a device that compresses a low-temperature, low-pressure refrigerant in the refrigerant pipes 18 and increases the pressure to increase the temperature. The refrigerant is a heat medium used to transfer heat in a refrigeration cycle. The compressor 14 is provided with a sensorless DC motor (not shown). The sensorless DC motor is a motor that is installed to rotate a compression mechanism that compresses the refrigerant in the compressor 14. In other words, the compressor 14 is started up by starting and rotating the sensorless DC motor, and the operation of the compressor 14 is initiated.

[0033] The condenser 15 is provided downstream of the heat exchange element 3 on the exhaust air duct 10. The condenser 15 releases heat from the refrigerant, which has been made high-temperature and high-pressure by the compressor 14, to the air (exhaust air flow 13). At that time, the refrigerant is condensed and liquefied under high pressure. In other words, since the temperature of the refrigerant introduced into the condenser 15 is higher than the temperature of the air (exhaust air flow 13), the air (exhaust air flow 13) is heated and the refrigerant is cooled. In other words, the heat exchange type ventilation device 1A is provided with a condenser cooling structure that cools the condenser 15 with the exhaust air flow 13.

[0034] In addition, since the condenser 15 is provided downstream of the heat exchange element 3 on the exhaust air duct 10, the condenser 15 can be cooled without deteriorating the efficiency of heat exchange between the exhaust air flow 13 and the intake air flow 12 by the heat exchange element 3. This will be described in detail below.

[0035] The dehumidification function of the heat exchange type ventilation device 1A is assumed to be used in the Japanese summer when outdoor air is hot and humid. In the Japanese summer, the intake air flow 12 flowing into the heat exchange element 3 is at a high temperature. However, it is desirable that the intake air flow 12 after heat exchange with the exhaust air flow 13 by the heat exchange element 3 is at a lower temperature. This is because the comfort of the user is improved if the intake air flow 12 after heat exchange flows indoors at a lower temperature. In order to make the intake air flow 12 after heat exchange with the exhaust air flow 13 by the heat exchange element 3 at a lower temperature, it is desirable that the exhaust air flow 13 flowing into the heat exchange element 3 is at a lower temperature. If the condenser 15 is provided upstream of the heat exchange element 3 on the exhaust air duct 10, the exhaust air flow 13 is heated by the condenser 15, and the heated exhaust air flow 13 flows into the heat exchange element 3. However, since the condenser 15 is provided downstream of the heat exchange element 3 on the exhaust air duct 10, the exhaust air flow 13 before being heated by the condenser 15 flows into the heat exchange element 3. In other words, the efficiency of heat exchange between the exhaust air flow 13 and the intake air flow 12 by the heat exchange element 3 is not deteriorated.

[0036] The expander 16 is a device that reduces the pressure of the high-pressure refrigerant liquefied by the condenser 15 to make it into a low-temperature, low-pressure liquid.

[0037] The evaporator 17 is provided in the supply air duct 11. The evaporator 17 absorbs heat from the air (supply air flow 12) using a refrigerant that has been made low-temperature and low-pressure by the expander 16. At that time, the refrigerant is evaporated under low pressure. That is, since the temperature of the refrigerant introduced into the evaporator 17 is lower than the temperature of the air (supply air flow 12), the air (supply air flow 12) is cooled and the temperature of the refrigerant is raised. That is, the heat exchange type ventilation device 1A has an evaporator heating structure that heats the evaporator 17 with the supply air flow 12. Both the condenser cooling structure and the evaporator heating structure can be said to be temperature adjustment structures.

[0038] Furthermore, the main body 2 is provided therein with a compressor discharge side temperature sensor 19, a compressor suction side temperature sensor 20, and a control unit 21A.

[0039] The compressor discharge side temperature sensor 19 is a downstream temperature detection unit that detects a downstream temperature, which is the temperature downstream in the refrigeration cycle of the compressor 14. The compressor discharge side temperature sensor 19 is provided on the refrigerant piping 18 downstream in the refrigeration cycle of the compressor 14. The compressor discharge side temperature sensor 19 is a sensor that measures the temperature of the discharge side of the compressor 14, i.e., the refrigerant discharge part of the compressor 14 that compresses and discharges the refrigerant, and a thermistor or a platinum resistor is mainly used. Since the temperature on the discharge side of the compressor 14 becomes high, a temperature sensor that can measure 10°C to 120°C is generally used.

[0040] The compressor suction side temperature sensor 20 is an upstream temperature detection unit that detects an upstream temperature, which is the temperature upstream in the refrigeration cycle of the compressor 14. The compressor suction side temperature sensor 20 is provided on the refrigerant pipe 18 upstream in the refrigeration cycle of the compressor 14. The compressor suction side temperature sensor 20 is a sensor that measures the temperature of the suction side of the compressor 14, i.e., the refrigerant suction part of the compressor 14 that sucks in the refrigerant vaporized in the evaporator 17, and mainly uses a thermistor or a platinum resistor. Since the temperature on the suction side of the compressor 14 is low, a temperature sensor that can measure temperatures from -10°C to 50°C is generally used.

[0041] The control unit 21A controls the start timing of the compressor 14. In other words, the control unit 21A controls the operation start timing of a sensorless DC motor mounted inside the compressor 14. The control contents of the control unit 21A will be described later.

[0042] The heat exchange type ventilation device 1A can dehumidify the intake air flow 12 using the evaporator 17 as a dehumidifier, in addition to the ventilation that performs the heat exchange described above. Here, the flow of dehumidification of the intake air flow 12 using the evaporator 17 will be described.

[0043] First, the control unit 21A starts the compressor 14 to compress the refrigerant. The compressed refrigerant becomes high temperature and high pressure, and is guided to the condenser 15. In the condenser 15, the refrigerant imparts heat to the exhaust gas flow 13, becoming a high-pressure liquid.

[0044] Next, the refrigerant liquefied in the condenser 15 is depressurized by the expander 16. When the compressor 14 is started, first, the opening degree of the expander 16 is set to be larger than the normal opening degree adjustment range in order to circulate the refrigerant.

[0045] Then, when the rotation speed of the sensorless DC motor of the compressor 14 stabilizes at a desired rotation speed, the opening of the expander 16 is narrowed down. Since abruptly narrowing the opening of the expander 16 leads to abrupt changes in the refrigerant pressure, which may cause the operation of the compressor 14 to become unstable or even lead to an abnormal stop, the opening of the expander 16 is adjusted in cycles of several tens of seconds.

[0046] The refrigerant is then decompressed in the expansion device 16 to become a low-temperature, low-pressure liquid that is more likely to evaporate, and is then guided to the evaporator 17. In the evaporator 17, the low-temperature, low-pressure refrigerant removes heat from the intake air stream 12 as it passes through the evaporator 17. At the same time, the moisture in the intake air stream 12 condenses, reducing the amount of moisture in the intake air stream 12, and the intake air stream 12 becomes low-humidity air. That is, the intake air stream 12 is dehumidified by the evaporator 17, which serves as a dehumidifier.

[0047] When dehumidification is not performed, the heat exchange type ventilation device 1A stops the compressor 14 and the expander 16 so that the refrigeration cycle does not operate.

[0048] Next, each function of the control unit 21A according to the embodiment of the present invention will be described with reference to Fig. 2. Fig. 2 is a schematic functional block diagram of the control unit 21A and its peripheral parts.

[0049] The control unit 21A includes a comparison unit 22, a storage unit 23, a determination unit 24A, and a device control unit 25A.

[0050] The comparison unit 22 acquires the downstream temperature from the compressor discharge side temperature sensor 19, and acquires the upstream temperature from the compressor suction side temperature sensor 20. Then, the comparison unit 22 compares the downstream temperature with the upstream temperature. Specifically, the comparison unit 22 calculates the temperature difference between the downstream temperature and the upstream temperature, and compares it with a threshold value stored in the storage unit 23, which will be described later.

[0051] Here, the reason why the comparison unit 22 compares the temperature difference between the downstream temperature and the upstream temperature with the threshold value will be described. Assume that the operation of the compressor 14 is stopped for some reason during operation of the compressor 14, for example, due to a sudden power interruption such as a momentary power outage. The refrigerant on the discharge side of the compressor 14 immediately after the operation of the compressor 14 is at high temperature and high pressure because it was compressed until just before the operation of the compressor 14 was stopped. In addition, the refrigerant on the suction side of the compressor 14 immediately after the operation of the compressor 14 is decompressed by the expander 16 and then passes through the evaporator 17, and is at a lower temperature and pressure than the discharge side of the compressor 14.

[0052] In order to resume dehumidification by the evaporator 17 after the power is restored, it is necessary to start the compressor 14, but attempting to start the compressor 14 when there is a large pressure difference between the refrigerant pressure on the discharge side of the compressor and the refrigerant pressure on the suction side of the compressor may fail. Failure to start the compressor 14 means failure to start the rotation of the motor mounted to rotate the compression mechanism that compresses the refrigerant inside the compressor 14. The reason for this failure to start the rotation of the motor is that the motor mounted inside the compressor 14 is a sensorless DC motor.

[0053] Here, a sensorless DC motor will be described. A sensorless DC motor is a type of DC motor that is not equipped with a magnetic pole detection element (hereinafter, Hall IC) for detecting the position of the magnetic pole of the rotor. The reason why a sensorless DC motor is used for the motor installed inside the compressor 14 is that the temperature inside the compressor 14 may exceed the upper limit of the usable temperature of the Hall IC, and a DC motor equipped with a Hall IC cannot be used. In a sensorless DC motor, a motor driver that controls the timing of energization to a stator that generates a rotating magnetic field for rotating the magnetic pole of the rotor estimates the position of the magnetic pole of the rotor to control the start and rotation speed of the motor. This is because, as described above, a sensorless DC motor is not equipped with a Hall IC, and therefore the position of the magnetic pole of the rotor cannot be identified.

[0054] Next, we will explain the characteristics and operation of a sensorless DC motor when it starts rotating. If there is a large discrepancy between the position of the stator and the position of the magnetic poles of the rotor when the sensorless DC motor starts rotating, even if the motor driver applies current to the stator to generate a rotating magnetic field, the rotor cannot follow the generated rotating magnetic field and the motor shaft does not rotate, a phenomenon known as loss of synchronization.

[0055] Therefore, in order to prevent loss of synchronism when the sensorless DC motor starts rotating, it is first necessary to align the magnetic pole positions of the stator and rotor before the sensorless DC motor starts rotating.To align the magnetic poles of the stator and rotor, a DC voltage is applied to the stator by the motor driver before the sensorless DC motor starts rotating.

[0056] When a DC voltage is applied to the stator, the stator temporarily becomes a fixed magnetic pole, either a north or south pole, and the magnetic poles of the stator and rotor attract each other, aligning the positions of the magnetic poles of the stator and rotor.

[0057] Then, after the magnetic poles of the stator and rotor are aligned, the sensorless DC motor starts rotating. However, to prevent loss of synchronization, the motor is forcibly rotated at a predetermined low rotation speed so that the torque required to rotate the motor shaft is small. After the rotation of the motor shaft has stabilized, the rotation speed is switched to the desired speed and normal rotation operation begins.

[0058] Therefore, when a sensorless DC motor starts up, torque is required in the process of aligning the magnetic poles of the stator and rotor of the sensorless DC motor, and in the process of forcibly rotating the sensorless DC motor at a specified low rotation speed. However, if the sensorless DC motor cannot generate the torque required in each of the above processes, loss of synchronization will occur.

[0059] Immediately after the compressor 14 stops operating, the refrigerant on the discharge side of the compressor 14 is at high temperature and high pressure, and the refrigerant on the suction side of the compressor 14 is at a lower temperature and pressure than the discharge side of the compressor 14. In other words, immediately after the compressor 14 stops operating, a large pressure difference occurs between the refrigerant pressure on the discharge side of the compressor 14 and the refrigerant pressure on the suction side of the compressor 14, and a large torque is required to start the sensorless DC motor. Here, the larger the pressure difference between the refrigerant pressure on the discharge side of the compressor 14 and the refrigerant pressure on the suction side of the compressor 14, the larger the torque required to start the sensorless DC motor. In other words, the larger this pressure difference is, the more difficult it is to start the sensorless DC motor.

[0060] In order to solve this problem and ensure that the compressor 14 is started, it is sufficient to wait for the time required for the pressure to be equalized (hereinafter, referred to as the pressure equalization time) before starting the compressor 14.

[0061] However, the pressure equalization time may become longer or shorter because it is affected by the rotation speed of the sensorless DC motor just before the compressor 14 stops operating, the effect of the outdoor temperature and humidity on the condenser 15 which communicates with the outdoors through the exhaust port 6, and the indoor temperature and humidity on the evaporator 17 which communicates with the indoors through the intake port 9.

[0062] If the pressure equalization time could be set according to the rotation speed of the sensorless DC motor, the outdoor temperature and humidity, and the indoor temperature and humidity immediately before the operation of the compressor 14 is stopped, it would be possible to start up the compressor 14 in the shortest time possible without startup failure. However, there are an extremely wide variety of combinations of the rotation speed of the sensorless DC motor, the outdoor temperature and humidity, and the indoor temperature and humidity immediately before the operation of the compressor 14 is stopped, and it is difficult to classify them into cases and prepare a pressure equalization time as a parameter that corresponds to all of them.

[0063] Therefore, the pressure equalization time is generally set to a time required to reliably start the compressor 14. In other words, the pressure equalization time is generally set to the longest pressure equalization time (hereinafter referred to as the maximum pressure equalization time) required to reliably achieve pressure equalization, regardless of the rotation speed of the sensorless DC motor immediately before the compressor 14 stops operating, the outdoor temperature and humidity conditions, and the indoor temperature and humidity conditions.

[0064] However, when the maximum pressure equalization time is set as the pressure equalization time, even if the compressor 14 is in a state where it can be started, it is necessary to wait until the maximum pressure equalization time has elapsed before starting the compressor 14, and it is not possible to promptly respond to a user's request for dehumidification.

[0065] To solve this problem, it is necessary to know that there is no pressure difference between the refrigerant pressure on the discharge side of the compressor 14 and the refrigerant pressure on the suction side of the compressor 14. In other words, when it is known that there is no pressure difference, the compressor 14 can be started at that point, so there is no need to wait until the maximum pressure equalization time has elapsed before starting the compressor 14.

[0066] One method of measuring the pressure of the refrigerant is to use a pressure sensor, but pressure sensors are expensive and it is not practical to install one just to determine pressure equalization.

[0067] Therefore, in the present invention, the pressure equalization is grasped using the compressor discharge side temperature sensor 19 and the compressor suction side temperature sensor 20. The compressor discharge side temperature sensor 19 is installed as standard in the refrigeration cycle in order to protect the compressor 14 by detecting an abnormally high temperature on the discharge side of the compressor 14, and the compressor suction side temperature sensor 20 is used to adjust the opening of the expander 16. In other words, by using the temperature sensors installed as standard, the pressure equalization can be grasped without increasing costs.

[0068] Next, a method for determining the pressure equalization using the compressor discharge side temperature sensor 19 and the compressor suction side temperature sensor 20 will be described.

[0069] While the compressor 14 is operating, the refrigerant in the condenser 15 is at a high temperature and high pressure, and the refrigerant in the evaporator 17 is at a low temperature and low pressure compared to the refrigerant in the condenser 15. If a power outage occurs in this state and the compressor 14 stops operating, the heat of the refrigerant in the refrigerant pipe 18 is released from the higher temperature to the lower temperature.

[0070] Specifically, the heat of the refrigerant on the discharge side of the compressor 14 is released to the refrigerant on the suction side of the compressor 14 via the expander 16. At the same time, the density of the refrigerant on the discharge side of the compressor 14 decreases, and the density of the refrigerant on the suction side of the compressor 14 increases. In other words, the pressure of the refrigerant on the discharge side of the compressor 14 decreases, and the pressure on the suction side of the compressor 14 increases. That is, it can be considered that the pressure and temperature of the refrigerant in the refrigerant pipe 18 are proportional to each other. Therefore, it can be considered that the pressure is equalized when the temperature of the refrigerant on the discharge side of the compressor 14 (downstream temperature) and the temperature of the refrigerant on the suction side of the compressor 14 (upstream temperature) become approximately the same.

[0071] In other words, in order to know that the pressure difference between the refrigerant pressure on the discharge side of compressor 14 and the refrigerant pressure on the suction side of compressor 14 has become small, it is necessary to know that the temperature difference between the downstream temperature and the upstream temperature has become small. In other words, by knowing that the temperature difference between the downstream temperature and the upstream temperature has become small, compressor 14 can be started quickly without having to wait until the maximum pressure equalization time has elapsed, and a user's request for dehumidification can be met quickly. This is the reason why comparison unit 22 compares the temperature difference between the downstream temperature and the upstream temperature with the threshold value.

[0072] The storage unit 23 is a so-called memory that stores a threshold value used by the comparison unit 22 when making a comparison. The threshold value is for comparing the temperature difference between the downstream temperature and the upstream temperature, and is, for example, a value determined in advance by an experiment or the like, and can be set arbitrarily. The threshold value is for determining that the pressure difference between the refrigerant pressure on the discharge side of the compressor 14 and the refrigerant pressure on the suction side of the compressor 14 has disappeared, and in this embodiment, as an example, the threshold value is set to 2°C. The threshold value is changed depending on the configuration of the refrigeration cycle to be installed and the performance of the condenser 15, the expander 16, and the evaporator 17.

[0073] Judgment unit 24A determines the operation of exhaust fan 4, intake fan 7, and compressor 14 based on the comparison result obtained by comparison unit 22.

[0074] Specifically, when the temperature difference between the downstream temperature and the upstream temperature is equal to or less than a threshold value (2° C. in this embodiment), the judgment unit 24A judges that the pressure difference between the refrigerant pressure on the discharge side of the compressor 14 and the refrigerant pressure on the suction side of the compressor 14 has disappeared, and determines the operation of starting the compressor 14. In other words, when the temperature difference between the downstream temperature and the upstream temperature is equal to or less than the threshold value, the judgment unit 24A determines the start of operation of the sensorless DC motor mounted inside the compressor 14.

[0075] Furthermore, when the temperature difference between the downstream temperature and the upstream temperature is greater than the threshold value, the determination unit 24A waits until the temperature difference between the downstream temperature and the upstream temperature becomes equal to or less than the threshold value, and then decides to start the operation of the sensorless DC motor.

[0076] Furthermore, when the temperature difference between the downstream temperature and the upstream temperature is greater than the threshold value, the judgment unit 24A determines that during standby until the temperature difference between the downstream temperature and the upstream temperature becomes equal to or less than the threshold value, the exhaust fan 4 is operated using the condenser cooling structure to cool the condenser 15 with the exhaust flow 13. Furthermore, the judgment unit 24A determines that the exhaust airflow of the exhaust flow 13 is to be made even greater than the initial exhaust airflow during standby.

[0077] Furthermore, when the temperature difference between the downstream temperature and the upstream temperature is greater than the threshold value, the judgment unit 24A determines that during standby until the temperature difference between the downstream temperature and the upstream temperature becomes equal to or less than the threshold value, the supply air fan 7 is operated using the evaporator heating structure to heat the evaporator 17 with the supply air flow 12. Furthermore, the judgment unit 24A determines that the supply air volume of the supply air flow 12 is to be made even larger than the initial supply air volume during standby.

[0078] The equipment control unit 25A controls the exhaust fan 4, the intake fan 7, and the compressor 14 based on the instruction content determined by the determination unit 24A.

[0079] Here, the control unit 21A is configured with a microcomputer. That is, the control unit 21A has therein a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), etc. The control unit 21A is connected to the compressor discharge side temperature sensor 19, the compressor suction side temperature sensor 20, the exhaust fan 4, the intake fan 7, and the compressor 14 through a driver and an internal bus. The CPU uses, for example, the RAM as a working area, executes a program stored in the ROM, and controls each operation by sending and receiving data and commands based on the execution results.

[0080] The control executed by the control unit 21A in the above configuration until the start of the compressor 14 will be described. Fig. 3 is a flowchart showing the control of the control unit 21A according to the embodiment of the present invention. In the flowchart, numbers are assigned starting with the initial letter S. For example, S01 indicates a processing step. However, the magnitude of the numerical value indicating the processing step has no relation to the processing order.

[0081] When dehumidification is performed by the heat exchange type ventilation device 1A, the comparison unit 22 compares whether the temperature difference, which is the value obtained by subtracting the upstream temperature from the downstream temperature, is equal to or less than the threshold value stored in the storage unit 23 (S01).

[0082] If the temperature difference is equal to or less than the threshold value stored in memory unit 23 (Yes in S01), judgment unit 24A decides to start the operation of the sensorless DC motor mounted inside compressor 14. Then, device control unit 25A starts the operation of the sensorless DC motor (S07). In other words, by using compressor discharge side temperature sensor 19 and compressor suction side temperature sensor 20, the sensorless DC motor can be started without waiting for the maximum pressure equalization time, so that the time until dehumidification starts can be shortened.

[0083] If the temperature difference is greater than the threshold value stored in the memory unit 23 (No in S01), the judgment unit 24A does not decide to start the operation of the sensorless DC motor, and decides to wait. Furthermore, the judgment unit 24A decides to cool the condenser 15 with the exhaust airflow 13 using the condenser cooling structure. The equipment control unit 25A starts the operation of the exhaust fan 4 so that the exhaust airflow of the exhaust airflow 13 becomes the initial exhaust airflow set in the heat exchange type ventilation device 1A (S02). This cools the refrigerant pipe 18 on the discharge side of the compressor 14 connected to the condenser 15, and the refrigerant in the refrigerant pipe 18 on the discharge side of the compressor 14. In other words, the temperature drop of the downstream temperature can be promoted, and the time until the temperature difference becomes equal to or less than the threshold value can be shortened. Therefore, the time until the dehumidification starts can be shortened.

[0084] Furthermore, the equipment control unit 25A changes the rotation speed of the exhaust fan 4 to temporarily make the exhaust air volume of the exhaust flow 13 larger than the initial exhaust air volume (S03). In this embodiment, as an example, the equipment control unit 25A operates the exhaust fan 4 to achieve the maximum air volume that can be set in the heat exchange type ventilator 1A. This can further promote the decrease in the downstream temperature, thereby further shortening the time until the temperature difference becomes equal to or less than the threshold value, and therefore further shortening the time until the dehumidification starts.

[0085] Furthermore, the judgment unit 24A determines to heat the evaporator 17 with the supply air flow 12 using the evaporator heating structure. The equipment control unit 25A starts the operation of the supply air fan 7 so that the supply air volume of the supply air flow 12 becomes the initial supply air volume set in the heat exchange type ventilation device 1A (S04). As a result, the refrigerant pipe 18 on the suction side of the compressor 14 connected to the evaporator 17 is heated, and the refrigerant in the refrigerant pipe 18 on the suction side of the compressor 14 is heated. In other words, since the temperature rise of the upstream temperature can be promoted, the time until the temperature difference becomes equal to or less than the threshold value can be further shortened. Therefore, the time until the dehumidification starts can be further shortened.

[0086] Furthermore, the equipment control unit 25A changes the rotation speed of the supply air fan 7 to temporarily make the supply air volume of the supply air flow 12 even larger than the initial supply air volume (S05). In this embodiment, as an example, the equipment control unit 25A operates the supply air fan 7 to achieve the maximum air volume that can be set in the heat exchange type ventilator 1A. This further promotes an increase in the upstream temperature, thereby further shortening the time until the temperature difference becomes equal to or less than the threshold value. Therefore, the time until dehumidification starts can be further shortened.

[0087] Then, the comparison unit 22 compares whether the temperature difference is equal to or less than the threshold value (S06). If the temperature difference is greater than the threshold value (No in S06), the judgment unit 24A decides to wait without deciding to start the operation of the sensorless DC motor. Then, the process of step S06 is repeated.

[0088] If the temperature difference is equal to or less than the threshold value (Yes in S06), the judgment unit 24A decides to start the operation of the sensorless DC motor mounted inside the compressor 14. Then, the device control unit 25A starts the operation of the sensorless DC motor (S07). This allows the sensorless DC motor to be started without waiting for the maximum pressure equalization time, thereby shortening the time until the dehumidification starts.

[0089] The present invention has been described above based on the embodiments, but the present invention is not limited to the above embodiments, and it can be easily inferred that various improvements and modifications are possible within the scope of the present invention without departing from the spirit of the present invention.

[0090] For example, in this embodiment, both the condenser cooling structure and the evaporator heating structure are used, but only one of the condenser cooling structure and the evaporator heating structure may be used. Also, neither the condenser cooling structure nor the evaporator heating structure may be used. In other words, some or all of steps 02 to 05 in the flowchart of FIG. 3 may not be executed. This allows for simpler control.

[0091] (Variation 1) The first modification will be described with reference to Fig. 4, focusing on the differences from the above embodiment. Fig. 4 is a diagram showing the configuration of a heat exchanger type ventilation device 1B in the first modification. The heat exchanger type ventilation device 1B has a partially different structure compared to the heat exchanger type ventilation device 1A. The differences between the heat exchanger type ventilation device 1B and the heat exchanger type ventilation device 1A will be described.

[0092] In the heat exchange type ventilation device 1A, the compressor 14 is provided upstream of the heat exchange element 3 on the exhaust air duct 10. However, in the heat exchange type ventilation device 1B, the compressor 14 is provided downstream of the heat exchange element 3 on the exhaust air duct 10. Specifically, the compressor 14 is provided downstream of the heat exchange element 3 on the exhaust air duct 10 and upstream of the condenser 15. This allows the compressor 14 to be cooled by the exhaust air duct 13 without deteriorating the heat exchange efficiency between the exhaust air duct 13 and the intake air duct 12. That is, the heat exchange type ventilation device 1B has a compressor cooling structure as a temperature adjustment structure that cools the compressor 14 provided downstream of the heat exchange element 3 on the exhaust air duct 10 with the exhaust air duct 13.

[0093] When the compressor 14 is cooled, the downstream temperature decreases. This is because the temperature of the refrigerant that has been made high-temperature and high-pressure by the compressor 14 is higher than the temperature of the air (exhaust air flow 13), so the air (exhaust air flow 13) is heated and the refrigerant introduced into the condenser 15 is cooled. During standby until the temperature difference between the downstream temperature and the upstream temperature becomes equal to or lower than the threshold value, the control unit 21A uses the temperature adjustment structure (compressor cooling structure) to control the temperature difference to be equal to or lower than the threshold value. This can promote the decrease in the downstream temperature during standby, thereby shortening the time until the temperature difference becomes equal to or lower than the threshold value. Therefore, the time until dehumidification starts can be shortened.

[0094] Also, similarly to the above embodiment, when the temperature difference between the downstream temperature and the upstream temperature is greater than the threshold value during standby, the control unit 21A may further increase the exhaust airflow rate of the exhaust flow 13 compared to the initial exhaust airflow rate during standby. This can further promote the decrease in the downstream temperature during standby, thereby further shortening the time until the temperature difference becomes equal to or less than the threshold value. Therefore, the time until dehumidification starts can be further shortened.

[0095] Also, as in the heat exchanger type ventilator 1A, the compressor 14 may be provided upstream of the heat exchange element 3 on the exhaust air duct 10. In this case, the efficiency of heat exchange between the exhaust airflow 13 and the intake airflow 12 is deteriorated, but the degree of freedom in the configuration is improved. In other words, it can be said that the heat exchanger type ventilator 1A also has a compressor cooling structure that cools the compressor 14 with the exhaust airflow 13 as a temperature adjustment structure.

[0096] (Variation 2) The second modification will be described with reference to Figs. 5, 6, and 7, focusing on the differences from the above embodiment. Fig. 5 is a diagram showing the configuration of a heat exchanger type ventilation device 1C in the second modification. The heat exchanger type ventilation device 1C has a partially different structure compared to the heat exchanger type ventilation device 1A. The differences between the heat exchanger type ventilation device 1C and the heat exchanger type ventilation device 1A will be described.

[0097] The heat exchange type ventilation device 1C includes an air path switching unit 26. The air path switching unit 26 can switch the air path of the exhaust airflow 13 between a bypass exhaust air path 27 that bypasses the heat exchange element 3 and an exhaust air path 10 that does not bypass the heat exchange element 3. In other words, the air path switching unit 26 can switch whether the air taken into the main body 2 through the inside air port 5 and blown out of the main body 2 through the exhaust port 6 passes through the heat exchange element 3 or does not pass through the heat exchange element 3. The air path switching unit 26 is, for example, a damper.

[0098] 5 shows the heat exchange type ventilation device 1C when the air path switching unit 26 switches the air path of the exhaust airflow 13 to the exhaust air path 10 that does not bypass the heat exchange element 3. The exhaust airflow 13 sucked in by the exhaust fan 4 passes through the heat exchange element 3, the exhaust fan 4, and the condenser 15 in the exhaust air path 10, and is discharged from the exhaust port 6 to the outdoors. The intake airflow 12 sucked in by the intake fan 7 passes through the heat exchange element 3, the intake air fan 7, and the evaporator 17 in the intake air path 11, and is supplied to the indoors from the intake port 9. The heat exchange type ventilation device 1C operates the exhaust fan 4 and the intake air fan 7, and exchanges heat in the heat exchange element 3 between the exhaust airflow 13 flowing through the exhaust air path 10 and the intake airflow 12 flowing through the intake air path 11.

[0099] FIG. 6 shows the heat exchange type ventilator 1C when the air path switching unit 26 switches the air path of the exhaust air flow 13 to the bypass exhaust air path 27 that bypasses the heat exchange element 3. The exhaust air flow 13 sucked in by the exhaust fan 4 passes through the compressor 14, the exhaust fan 4, and the condenser 15 in the bypass exhaust air path 27, and is exhausted to the outdoors from the exhaust port 6. As a result, the heat exchange type ventilator 1C does not exchange heat between the exhaust air flow 13 and the intake air flow 12. One of the purposes of providing the bypass exhaust air path 27 is to introduce the outdoor air directly into the room without heat exchange when the temperature of the outdoor air is lower than the temperature of the indoor air, for example, during the spring and summer in Japan. This makes it possible to reduce the power consumption when cooling the room with an air conditioner.

[0100] An example of the switching operation from exhaust air duct 10 to bypass exhaust air duct 27 using air duct switching unit 26 will be described. Heat exchange type ventilation device 1C compares the temperature difference between the indoor air and the outdoor air, and when the temperature of the outdoor air becomes lower than the indoor air temperature by a certain value or more, air duct switching unit 26 switches the air duct of exhaust air flow 13 from exhaust air duct 10 to bypass exhaust air duct 27. Exhaust air flow 13 is sucked in by exhaust fan 4 and is discharged from inside air port 5 directly to the outdoors through exhaust port 6 without passing through heat exchange element 3. Although supply air flow 12 passes through heat exchange element 3, exhaust air flow 13 does not pass through heat exchange element 3, and is supplied into the room without heat exchange with exhaust air flow 13.

[0101] In the heat exchange type ventilation device 1C, the compressor 14 is provided on the bypass exhaust air duct 27. That is, the heat exchange type ventilation device 1C has a compressor cooling structure as a temperature adjustment structure that cools the compressor 14 provided on the bypass exhaust air duct 27 with the exhaust air flow 13. In the summer in Japan, when dehumidification of the intake air flow 12 is often performed, the temperature of the exhaust air flow 13 after the heat exchange is higher than that of the exhaust air flow 13 before the heat exchange. This is because the temperature of the intake air flow 12 before the heat exchange is higher than that of the exhaust air flow 13 before the heat exchange, and the heat of the intake air flow 12 is transferred to the exhaust air flow 13 by the heat exchange. In other words, cooling the compressor 14 by the exhaust air flow 13 without heat exchange during standby until the temperature difference between the downstream temperature and the upstream temperature becomes equal to or lower than the threshold value is more efficient. Therefore, it is preferable that the compressor 14 is provided on the bypass exhaust air duct 27, not on the exhaust air duct 10. This can promote a decrease in the downstream temperature during standby, thereby shortening the time until the temperature difference becomes equal to or less than the threshold value, thereby shortening the time until dehumidification starts.

[0102] The heat exchange type ventilation device 1C includes a control unit 21B. Each function of the control unit 21B according to the second modification will be described with reference to Fig. 7. Fig. 7 is a schematic functional block diagram of the control unit 21B and its peripheral parts. The difference between control unit 21B and control unit 21A will be described. Control unit 21B includes determination unit 24B instead of determination unit 24A. Based on the comparison result obtained by comparison unit 22, determination unit 24B determines the operation of exhaust fan 4, intake fan 7, and compressor 14, and also determines the operation of air-path switching unit 26.

[0103] Specifically, when the temperature difference between the downstream temperature and the upstream temperature is equal to or less than the threshold value, the judgment unit 24B judges that the pressure difference between the refrigerant pressure on the discharge side of the compressor 14 and the refrigerant pressure on the suction side of the compressor 14 has disappeared, and determines the operation of starting the compressor 14. In other words, when the temperature difference between the downstream temperature and the upstream temperature is equal to or less than the threshold value, the judgment unit 24B determines the start of operation of the sensorless DC motor mounted inside the compressor 14.

[0104] Furthermore, when the temperature difference between the downstream temperature and the upstream temperature is greater than the threshold value, the determination unit 24B waits until the temperature difference between the downstream temperature and the upstream temperature becomes equal to or less than the threshold value, and then decides to start the operation of the sensorless DC motor.

[0105] Furthermore, when the temperature difference between the downstream temperature and the upstream temperature is greater than the threshold value, the judgment unit 24B determines that during standby until the temperature difference between the downstream temperature and the upstream temperature becomes equal to or less than the threshold value, the air path switching unit 26 switches the air path of the exhaust airflow 13 to the bypass exhaust air path 27, operates the exhaust fan 4, and cools the compressor 14 with the exhaust airflow 13 using the compressor cooling structure. Furthermore, the judgment unit 24B may determine that the exhaust air volume of the exhaust airflow 13 is made even larger than the initial exhaust air volume during standby. This can further promote the temperature drop of the downstream temperature during standby, and therefore the time until the temperature difference becomes equal to or less than the threshold value can be further shortened. Therefore, the time until dehumidification starts can be further shortened.

[0106] The control unit 21B includes an equipment control unit 25B instead of the equipment control unit 25A. The equipment control unit 25B controls the exhaust fan 4, the intake fan 7, the compressor 14, and also the air-path switching unit 26 based on the instruction content determined by the determination unit 24B.

[0107] In addition, in the first and second modified examples, similarly to the above embodiment, a condenser cooling structure and an evaporator heating structure may be further used to make the temperature difference equal to or less than the threshold. By combining a plurality of temperature adjustment structures, the time until the temperature difference becomes equal to or less than the threshold can be further shortened. Therefore, the time until the start of dehumidification can be further shortened.

[0108] (Summary of the invention) The heat exchange type ventilation fan of the present invention comprises: a supply air fan that supplies air from outside a space as an intake air flow into a space via an intake air duct; a dehumidification unit that dehumidifies the intake air flow by utilizing a refrigeration cycle in which a compressor, a condenser, an expander, and an evaporator are connected in that order; a sensorless DC motor for driving the compressor; an upstream temperature detection unit that detects an upstream temperature, which is the upstream temperature in the refrigeration cycle of the compressor; a downstream temperature detection unit that detects a downstream temperature, which is the downstream temperature in the refrigeration cycle of the compressor; and a control unit that controls the timing of starting operation of the sensorless DC motor, wherein when starting up the compressor, if the temperature difference between the downstream temperature and the upstream temperature is equal to or less than a predetermined threshold, the control unit starts operation of the sensorless DC motor, and if the temperature difference between the downstream temperature and the upstream temperature is greater than the predetermined threshold, the control unit waits until the temperature difference between the downstream temperature and the upstream temperature becomes equal to or less than the predetermined threshold and then starts operation of the sensorless DC motor.

[0109] By comparing the temperature difference between the downstream temperature and the upstream temperature with a predetermined threshold value, it is possible to determine whether the sensorless DC motor for starting the compressor can be started, thereby enabling the compressor to be started quickly.

[0110] The system may also include a temperature adjustment structure that includes an exhaust fan that exhausts air within the space as an exhaust flow via an exhaust duct to outside the space, a heat exchange element that exchanges heat between the supply air flow and the exhaust flow, and at least one of a condenser cooling structure that cools the condenser provided downstream of the heat exchange element on the exhaust duct with the exhaust flow, or an evaporator heating structure that heats the evaporator provided on the supply air duct and functions as the dehumidifier with the supply air flow, and the control unit may use the temperature adjustment structure to control the temperature difference to below the predetermined threshold value during standby.

[0111] This makes it possible to shorten the time required for the temperature difference between the downstream temperature and the upstream temperature to become equal to or lower than a predetermined threshold value using the temperature adjustment structure.

[0112] In addition, the temperature adjustment structure may be the condenser cooling structure, and the control unit may increase the exhaust air volume of the exhaust flow even more than the initial exhaust air volume during standby when the temperature difference between the downstream temperature and the upstream temperature is greater than the specified threshold during standby.

[0113] This makes it possible to further reduce the time required for the temperature difference between the downstream temperature and the upstream temperature to become equal to or less than the predetermined threshold value.

[0114] In addition, the temperature adjustment structure may be the evaporator heating structure, and the control unit may increase the supply air volume of the supply air flow even more than the initial supply air volume during standby when the temperature difference between the downstream temperature and the upstream temperature is greater than the specified threshold during standby.

[0115] This makes it possible to further reduce the time required for the temperature difference between the downstream temperature and the upstream temperature to become equal to or less than the predetermined threshold value.

[0116] The temperature adjustment structure may include an exhaust fan that exhausts air within the space as an exhaust flow via an exhaust duct to outside the space, a heat exchange element that exchanges heat between the intake air flow and the exhaust flow, and a compressor cooling structure that cools the compressor provided downstream of the heat exchange element on the exhaust duct with the exhaust flow, and the control unit may use the temperature adjustment structure to control the temperature difference to below the predetermined threshold value during standby.

[0117] This makes it possible to reduce the time required for the temperature difference between the downstream temperature and the upstream temperature to become equal to or lower than a predetermined threshold value using the compressor cooling structure.

[0118] an exhaust fan that exhausts the air in the space to the outside of the space as an exhaust flow; The temperature adjustment structure may include a heat exchange element provided on the exhaust duct for exchanging heat between the intake air flow and the exhaust air flow flowing through the exhaust duct, an air path switching unit capable of switching the air path of the exhaust air flow between a bypass exhaust air path that bypasses the heat exchange element and the exhaust air path that does not bypass the heat exchange element, and a compressor cooling structure that cools the compressor provided on the bypass exhaust air duct with the exhaust air flow, and the control unit may use the temperature adjustment structure to control the temperature difference to below the predetermined threshold value during the standby period.

[0119] This makes it possible to reduce the time required for the temperature difference between the downstream temperature and the upstream temperature to become equal to or lower than a predetermined threshold value using the compressor cooling structure.

[0120] In addition, the temperature adjustment structure may be the compressor cooling structure, and the control unit may make the exhaust air volume of the exhaust flow even larger than the initial exhaust air volume during standby when the temperature difference between the downstream temperature and the upstream temperature is larger than the predetermined threshold value during standby.

[0121] This makes it possible to further reduce the time required for the temperature difference between the downstream temperature and the upstream temperature to become equal to or less than the predetermined threshold value. [Industrial Applicability]

[0122] INDUSTRIAL APPLICABILITY The heat exchange type ventilation device according to the present invention is useful as a heat exchange type ventilation device having a dehumidification function utilizing a refrigeration cycle. [Explanation of symbols]

[0123] 1A Heat exchange type ventilation equipment 1B Heat exchange type ventilation equipment 1C Heat exchange type ventilation equipment 2 Main unit 3 Heat exchange element 4. Exhaust Fan 5 Inner air vent 6 Exhaust port 7. Intake fan 8. Outside air vent 9 Air supply port 10 Exhaust duct 11 Air supply duct 12 Intake air flow 13 Exhaust flow 14 Compressor 15 Condenser 16 Expander 17 Evaporator 18 Refrigerant piping 19 Compressor discharge temperature sensor 20 Compressor suction side temperature sensor 21A Control section 21B Control section 22 Comparison section 23 Memory section 24A Judgment Department 24B Judgment Department 25A Equipment control section 25B Equipment control section 26 Air path switching section 27 Bypass exhaust duct

Claims

1. an intake fan that supplies air outside the space as an intake air flow into the space via an intake air duct; a dehumidification unit that dehumidifies the intake air flow by using a refrigeration cycle in which a compressor, a condenser, an expander, and an evaporator are connected in this order; a sensorless DC motor for driving the compressor; an upstream temperature detection unit that detects an upstream temperature, which is an upstream temperature in the refrigeration cycle of the compressor; a downstream temperature detection unit that detects a downstream temperature, which is a temperature downstream in the refrigeration cycle of the compressor; A control unit that controls a timing for starting operation of the sensorless DC motor; Equipped with The control unit is When starting the compressor, When the temperature difference between the downstream temperature and the upstream temperature is equal to or smaller than a predetermined threshold value, the operation of the sensorless DC motor is started. When the temperature difference between the downstream temperature and the upstream temperature is greater than the predetermined threshold, the heat exchange type ventilation device waits until the temperature difference between the downstream temperature and the upstream temperature becomes equal to or less than the predetermined threshold, and then starts operating the sensorless DC motor.

2. an exhaust fan that exhausts air in the space to the outside of the space as an exhaust flow via an exhaust air duct; a heat exchange element for exchanging heat between the intake air flow and the exhaust air flow; a condenser cooling structure that cools the condenser provided downstream of the heat exchange element on the exhaust air duct with the exhaust air flow, or an evaporator heating structure that heats the evaporator that is provided on the supply air duct and functions as the dehumidifier with the supply air flow, as a temperature adjustment structure; The control unit is 2. The heat exchange type ventilation device according to claim 1, wherein the temperature difference is controlled to be equal to or lower than the predetermined threshold value by using the temperature adjustment structure during the standby period.

3. the temperature adjustment structure is the condenser cooling structure, The control unit is During the standby period, 3. The heat exchange type ventilation device according to claim 2, wherein when the temperature difference between the downstream temperature and the upstream temperature is greater than the predetermined threshold value, the exhaust air volume of the exhaust flow is made larger than the initial exhaust air volume during standby.

4. the temperature adjustment structure is the evaporator heating structure, The control unit is During the standby period, 4. A heat exchange type ventilation device according to claim 2, wherein when the temperature difference between the downstream temperature and the upstream temperature is greater than the predetermined threshold value, the supply air volume of the supply air flow is made larger than the initial supply air volume during standby.

5. an exhaust fan that exhausts air in the space to the outside of the space as an exhaust flow via an exhaust air duct; a heat exchange element for exchanging heat between the intake air flow and the exhaust air flow; a compressor cooling structure that cools the compressor provided downstream of the heat exchange element on the exhaust air duct by the exhaust air flow, as a temperature adjustment structure; The control unit is 2. The heat exchange type ventilation device according to claim 1, wherein the temperature difference is controlled to be equal to or lower than the predetermined threshold value by using the temperature adjustment structure during the standby period.

6. an exhaust fan that exhausts the air in the space to the outside of the space as an exhaust flow; a heat exchange element provided on the exhaust air duct for exchanging heat between the intake air flow and an exhaust air flow passing through the exhaust air duct; an air path switching unit capable of switching an air path of the exhaust air flow between a bypass exhaust air path that bypasses the heat exchange element and the exhaust air path that does not bypass the heat exchange element; a compressor cooling structure that cools the compressor provided on the bypass exhaust air duct with the exhaust air flow as a temperature adjustment structure; The control unit is 2. The heat exchange type ventilation device according to claim 1, wherein the temperature difference is controlled to be equal to or lower than the predetermined threshold value by using the temperature adjustment structure during the standby period.

7. The control unit is During the standby period, 7. The heat exchange type ventilation device according to claim 5, wherein when the temperature difference between the downstream temperature and the upstream temperature is greater than the predetermined threshold value, the exhaust air volume of the exhaust flow is made larger than the initial exhaust air volume during standby.

Images