JPH0349015B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a dehumidification device using a refrigeration cycle.

[Prior art]

A conventional dehumidifier was constructed as shown in FIG. In the figure, 1 is a compressor, 2 is a condenser,
3 is a throttle device, 4 is a cooler, and these are successively communicated through a refrigerant pipe 5 to constitute a refrigeration cycle. 6 is a motor for driving the compressor 1, 7 is an AC power supply,
8 is a circuit that supplies power to the electric motor 6.

In the dehumidifying device configured in this way, the refrigerant discharged from the compressor 1 exchanges heat with the air B in the condenser 2 and is liquefied. Air B becomes air C by increasing its temperature and decreasing its relative humidity. The liquefied refrigerant is sent to the throttling device 3.
It is depressurized, becomes a low-pressure, low-temperature gas-liquid mixture, flows into the cooler 4, exchanges heat with air A, evaporates, and is sucked into the compressor 1. Air A is cooled and dehumidified to become air B described above. That is, air A becomes C and dehumidification is performed. In this process, as the humidity of the air A decreases, the dew point temperature also decreases, so dehumidification cannot be achieved unless the surface temperature of the cooler 4 is lowered. Therefore, when the valve opening degree of the throttle device 3 is reduced to lower the evaporation temperature, the specific volume of the refrigerant sucked into the compressor 1 increases, and the amount of refrigerant circulation decreases. As a result, a decrease in the refrigerating capacity is added to a decrease in the amount of dehumidification due to a decrease in humidity, further reducing the amount of dehumidification. In other words, conventional dehumidifiers have a drawback in that their dehumidifying ability is significantly reduced when the humidity is low. Also, since air A flows from the cooler to the condenser, if air A is low temperature, both the evaporation temperature and condensation temperature will decrease, resulting in a very light load, and if air A is high temperature, the evaporation temperature and condensation temperature will decrease. As the temperature rises at the same time, the load becomes extremely high. In other words, the load fluctuation range is very large, so if you select an electric motor 6 to drive the compressor 1 with a capacity that matches the high load to avoid overloading, not only will the capacity be wasted but there will be no efficiency when the load is light. There was also a drawback.

[Summary of the invention]

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and it detects the humidity and temperature of the air flowing into the cooler, and adjusts the valve opening of the throttle device and compression according to this detection signal. By controlling the frequency of the variable frequency power supply circuit for energizing the machine drive motor according to predetermined characteristics, the dehumidification capacity does not decrease even when humidity decreases, and load fluctuations are small. Furthermore, the purpose is to provide an efficient dehumidification device.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a schematic configuration diagram showing an embodiment of the present invention. In the figure, 1 is a compressor, 2 is a condenser, 4 is a
5 is a cooler, 5 is a refrigerant pipe, 6 is a compressor driving electric motor, 7 is an AC power source, and 8 is a power supply circuit, which are the same as those of the conventional one. Reference numeral 9 denotes an electric expansion valve whose opening degree changes according to changes in electrical input, and acts as a throttle device. 10 is cooler 4
a humidity sensor that detects the humidity of air A flowing into the
11 is a temperature sensor that detects the temperature of air A; 12
is provided in the power supply circuit 8 to the electric motor 6,
The rotational speed of the electric motor 6 is changed by increasing or decreasing its output frequency using a variable frequency power supply circuit composed of a rectifier circuit and a variable frequency inverter circuit. 13 inputs the detection signals of the humidity sensor 10 and temperature sensor 11, and according to these input signals, the valve opening degree and output frequency are set in advance.
The controller is, for example, a microcomputer that controls the electric expansion valve 9 and the variable frequency power supply circuit 12. FIG. 3 shows the control of the electric expansion valve 9 by the controller 13, in which the optimal valve opening degree at the rated power frequency of the inverter circuit is determined in advance by experiment with respect to changes in the humidity detected by the humidity sensor 10 and the temperature detected by the temperature sensor 11. FIG. 4 shows the control characteristics of the variable frequency power supply circuit 12 using the controller 13, in which the optimum output frequency at the rated valve opening is determined in advance by experiment with respect to changes in humidity detected by the humidity sensor 10 and temperature detected by the temperature sensor 11. The control characteristics of each are shown.

Next, the control operation by this controller 13 is shown in FIG.
This will be explained with reference to FIG. Now, for example, air A is 30
℃, the input signal to the controller 13 becomes a in FIGS. 3 and 4, the valve opening is 55%, and the output frequency is 58 Hz. Therefore, if the temperature of air A remains at 30℃ and the humidity drops to 40%, the input signal becomes b, the valve opening decreases to 35%, the evaporation temperature decreases, and the dew point of air A decreases. Since the surface temperature of the cooler 4 decreases in proportion to the decrease in temperature, water vapor in the air A condenses on the surface of the cooler 4. In other words, dehumidification is carried out without fail. Further, at this time, the output frequency increases to 68 Hz, and the rotation speed of the compressor 1 is increased. In other words, the decrease in the amount of refrigerant circulated due to the decrease in evaporation temperature is compensated for by this increase in rotational speed. Therefore, the dehumidifying ability when the humidity decreases is greater than that of the conventional method. Next, consider a case where the humidity of air A remains 70% and the temperature drops to 20°C. In this case, the input signal becomes c, the valve opening becomes 45%, the output frequency becomes 62 Hz, the evaporation temperature decreases, and the rotational speed increases. In other words, in this case as well, heat is taken from air A to ensure the amount of heat exchange, the evaporation temperature is lowered to cope with the decrease in dew point temperature, and the accompanying decrease in the amount of refrigerant circulation is compensated for by increasing the rotation speed of compressor 1. Let's make up for it. Furthermore, the temperature of air A is 40
Consider the case where the temperature and humidity rise to 80%. In this case, the input signal becomes d, the valve opening becomes 70%, the output frequency becomes 44 Hz, the evaporation temperature increases, and the rotation speed of the compressor 1 decreases. At this time, if the evaporation temperature remains the same, the difference between the air temperature and the evaporation temperature will increase, the degree of superheating of the refrigerant at the outlet of the cooler 4 will increase, and together with the rise in the condensation temperature, the discharge gas temperature will increase. The abnormal temperature rise of the compressor 1 is maintained at an appropriate degree of superheating by increasing the evaporation temperature due to the increase in the valve opening, thereby preventing the above-mentioned abnormal temperature rise. Note that even if the evaporation temperature rises, there is no problem in dehumidification because the dew point temperature is high in this case.
On the other hand, an increase in the amount of work of the compressor 1 due to an increase in the amount of refrigerant circulated due to an increase in the evaporation temperature is offset by a decrease in the number of rotations, so that the electric motor 6 is not overloaded.

〔Effect of the invention〕

As described above, according to the present invention, the humidity and temperature of the air A flowing into the cooler 4 are detected, and the optimum valve opening degree of the throttle device 9 and the compressor driving electric motor are determined in advance. Since a rotation speed of 6 is obtained,
Even air with a low dew point temperature can be dehumidified, the dehumidification ability under low humidity conditions can be increased, and the electric motor 6 can be operated efficiently without waste. Furthermore, various effects can be obtained, such as being able to prevent abnormal temperature rises in the discharged gas and compressor 1 and overloading the electric motor 6 under high temperature and high humidity conditions.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of a conventional dehumidifying device, Fig. 2 is a schematic diagram of an embodiment of the present invention, and Fig. 3 is a schematic diagram of a conventional dehumidifying device.
4 are control characteristic diagrams of the dehumidification device controller shown in FIG. 2. In the figure, 1 is a compressor, 2 is a condenser, 4 is a cooler, 5 is a refrigerant pipe, 6 is an electric motor for driving the compressor,
7 is an AC power supply, 9 is an electric expansion valve that acts as a throttle device, 10 is a humidity sensor, 11 is a temperature sensor,
12 is a variable frequency power supply circuit, and 13 is a controller. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1 A compressor, a condenser, a throttle device, and a cooler are successively connected through refrigerant piping to form a refrigeration cycle, and the air that has been cooled and dehumidified by the cooler is heated by the condenser. In a dehumidifying device that dehumidifies, a humidity sensor detects the humidity of the air flowing into the cooler, a temperature sensor detects the temperature of the air flowing into the cooler, and a variable frequency voltage is supplied to the electric motor that drives the compressor. In response to the detection signals of the variable frequency power supply circuit, the humidity sensor, and the humidity sensor, the valve of the throttle device is adjusted in accordance with a predetermined valve opening characteristic that decreases as the humidity and temperature detected by these sensors decrease. In addition to controlling the opening degree, the humidity detected by each sensor above,
A dehumidifier comprising: a controller that controls the frequency of the variable frequency power supply circuit according to predetermined frequency characteristics such that the frequency increases as the detected temperature decreases.