JPS63135733A - Method for supplying thermohygrostatic air - Google Patents

Abstract

PURPOSE:To enable a humidity control of a target space to be performed at a high accuracy when thermohygrostatic air is to be supplied to an icing housing by a method wherein a thermal energy is added to an air cooler to control a cooling capability and a temperature of air passing through the air cooler is made to have a dew point corresponding to a target value. CONSTITUTION:A coolant heater 6 is arranged at a suitable location in a coolant flow passage 7d extending from a coolant expander 7c to a coolant evaporator 7 in a refrigerating cycle and then coolant flowing into the coolant evaporator 7 can be heated. The coolant heater 6 is operated in such a way as a temperature of air passed through the coolant evaporator 7 and cooled becomes a dew point corresponding to air having a condition of temperature and a humidity of a target control value of a thermohygrostatic chamber 3 so as to adjust a cooling capability of the coolant evaporator 7. In addition, the air passed through the coolant evaporator 7 is heated by an air heater 8 and increased up to a desired control temperature and then supplied to the thermohygrostatic chamber 3.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a method for maintaining a target space under constant temperature and humidity conditions in a temperature range of 0°C or lower, such as an ice-warming warehouse, an ice-warming warehouse, or an environmental testing machine. The present invention relates to a method of supplying constant temperature air to a target space, which is particularly suitable for various cases.

Prior Art When constant temperature and constant humidity air is supplied to a target space that is to be maintained at constant temperature and humidity conditions, it is first cooled down to a temperature lower than the target temperature using an air cooler using a refrigeration cycle.
This is then heated with an air reheater such as an electric heater to raise the temperature to the desired temperature, and is generally humidified with a humidifier to adjust the humidity to the desired level before being sent to the target space. . A constant-temperature and constant-humidity air supply machine that is equipped with a blower, an air cooler, an air heater, and a humidifier in such an air flow path forms a series of air circulation flow paths with the constant temperature and constant temperature room that is the target space. is combined with Therefore, when it is necessary to maintain a target space at a relatively low temperature by cooling it once below freezing using an air cooler, moisture in the circulating air may form frost on the air cooler. Therefore, if continuous operation is continued, the cooling fins will become clogged with frost, making cooling impossible. Therefore, defrosting operation must be performed at regular intervals or by detecting frost formation using a sensor. However, this defrosting operation is performed by heating the air cooler, which has the disadvantage that the temperature and humidity conditions of the target space are significantly disturbed. In particular, when humidifying to achieve a constant humidity state, if the controlled temperature of the target space is below freezing, frost may form on the humidifying port, causing the humidification amount to fluctuate, or the moisture released from the humidifier may However, it freezes in the air, making uniform humidification impossible, and creating a stable constant humidity state is extremely difficult.

Structure of the Invention The present invention has been made in view of the above circumstances, and the gist thereof is to install a refrigerant evaporator of a refrigeration cycle as an air cooler and a refrigerant evaporator in an air flow path equipped with a blower. In an apparatus comprising a constant temperature air supply machine equipped with an air heater provided on the leeward side of the container, and a constant temperature constant room connected to the constant temperature air supply machine so as to form a series of air circulation channels, the above-mentioned A refrigerant heater is installed at an appropriate location in the refrigerant flow path from the refrigerant expander to the refrigerant evaporator in the refrigeration cycle, so that the refrigerant flowing into the refrigerant evaporator can be heated, and the cooled air can be heated after passing through the refrigerant evaporator. The refrigerant heater is operated to adjust the cooling capacity of the refrigerant evaporator so that the temperature of the refrigerant evaporator is exactly equal to the dew point temperature corresponding to the temperature and humidity condition of the control target value of the constant temperature and humidity chamber, and the refrigerant evaporator is heated. The method for supplying constant temperature and constant temperature air is characterized in that the air that has passed through is heated by an air heater to raise the temperature to the control target value, and then is supplied to the constant temperature and humidity chamber.

Hereinafter, the method of the present invention will be explained in detail based on an example of an apparatus for carrying out the present invention, with reference to the drawings.

FIG. 1 conceptually shows an example of an apparatus for carrying out the method according to the present invention, in which a partition wall 2 is placed between the facing side walls in a box 1 surrounded by a heat insulating wall 1a. By providing the space between the upper edge 2a of the partition wall 2 and the ceiling surface 1b of the box body 1 and the partition wall A slight gap is provided between the lower M2b and the floor surface 1c, forming an air supply port 4a and an air return port 4b, respectively.

The air flow path 4 is blown by the air blower 8!5 provided above.
The air entering through the air return port 4b rises, reaches the air supply port 4a, and is configured to be supplied to the constant temperature and humidity chamber 3 again. In such an air flow path 4, refrigerant compression 8!
7a, a cold WAN device 7b, a capillary tube 7C as a refrigerant expander, and a refrigerant evaporator 7. The refrigerant evaporator 7 of the refrigerator is housed as an air cooler. An air heater 8 consisting of an electric heater is housed to form a constant temperature and humidity air supply device.

From the capillary tube 7c of the refrigerator to the refrigerant evaporator 7
In the middle of the refrigerant flow path 7d leading to the refrigerant flow path 7d, as shown in the second motherboard, a heating wire 6a is wound around the conductor 7 (7d) forming the refrigerant flow path 7d, and the outside of the heating wire 6a is covered with a heat-resistant M6b. A refrigerant heater 6 is provided. 10 is a temperature detector such as a thermistor, which detects the temperature of the air supplied into the constant temperature and humidity chamber 3 from the air supply port 4a, inputs this detection signal to the air heater controller 11, and 11 compares a preset target value and an input value, and outputs an output to a drive circuit 12 such as a relay circuit according to the deviation, thereby controlling the operation of the air heater 8.

Similarly, 13 is a humidity detector that can maintain accuracy even at subzero temperatures, such as a humidity detector that detects humidity by a change in electrical resistance due to moisture adsorption in a thin film of a polymer compound, and its detection signal is input to the refrigerant heater controller 14, and the cooling capacity of the refrigerant evaporator 7 is controlled by controlling the operation of the refrigerant heater 6 via the drive circuit 15 according to the deviation between the detected value and the set value. It is configured to adjust.

Using such a device, for example, when trying to maintain the constant temperature and humidity chamber 3 at a temperature of -10°C and a relative humidity of 30%, the cooling capacity of the refrigerant evaporator 7 can be increased to 130°C for air at around 10°C. If you set it to be able to cool down to about ℃,
Since the dew point temperature of air with the target value of -10°C and humidity and 30% RH is -23°C, the temperature of the air that enters from the air return port 4b and is cooled after passing through the refrigerant evaporator 7 is By operating the refrigerant heater 6 to heat the refrigerant to exactly -23°C, the refrigerant evaporation temperature of the refrigerant evaporator 7 is increased by that amount.

Thus, the air that has passed through the refrigerant evaporator 7 enters the air heater 8 at a dew point temperature corresponding to the target value, where it is
By being heated to the target temperature, air of 110'030% R11 is supplied toward the target space with extremely high accuracy.

In the apparatus of the above embodiment, the refrigerant heater is exemplified as one that heats from the outside of the refrigerant conduit, but as shown in FIG. (7d) may be of a type in which a refrigerant heating chamber 6c is interposed in the middle, and the sheathed heater 6d is housed in the chamber in an air-liquid tight manner.

The feature of the present invention is that thermal energy is directly applied to the air cooler itself to control its cooling capacity, and the temperature of the air passing through it is brought to a dew point temperature corresponding to a target value. By combining this method with a conventional method for controlling the capacity of an air cooler (refrigerant evaporator), it is possible to achieve even higher precision temperature and humidity control. For example, refrigerant compression 8!
As 7a, a rotary compressor is used and the temperature of the air cooler is controlled by capacity control using an inverter based on the signal of the temperature detector 10, or the expander 7c is an electronic linear expansion valve, Similarly, in order to control the capacity of the air cooler by controlling the refrigerant flow rate, and furthermore, for the purpose of adjusting the amount of refrigerant to the air cooler, the refrigerant flow path 7d is branched into a plurality of branch flow paths. A conventional method of controlling the refrigerant flow rate, such as a method in which expanders and electromagnetic on-off valves each having a different flow rate are provided to selectively open and close each branch flow path to roughly control the refrigerant inflow amount, and the present application By combining these methods, temperature and humidity can be controlled with even higher precision.

Note that the humidifier is not necessary for temperature and humidity control under the conditions of the specific example described above, so it is omitted in the embodiment shown in FIG. You may also have a humidifier in place for use.

Effects Conventional constant-temperature, constant-humidity air supply methods use an air cooler (refrigerant evaporator) to cool and dehumidify the air, then raise it to the target temperature, and then humidify the air to achieve the target temperature and humidity conditions. Therefore, if the air cooler has no choice but to cool the incoming air to below 0°C, continuous operation becomes impossible due to frost formation on the cooling fins, etc. control is greatly disturbed, making it difficult to accurately control humidity in the target space at temperatures below 0°C. In contrast, in the case of the present method, even in such a low temperature range, when the operation enters a steady state and the target space reaches around the target value, the air entering the air cooler is Since the conditions are such that the dew point is reached exactly when cooled, almost no frost formation occurs. Therefore, humidity control can be achieved with extremely high precision when the dew point is below the freezing point or when maintaining the target space at a temperature below the freezing point, and moreover, this can be stably maintained over a long period of time. A humidifier is almost unnecessary when controlling humidity at sub-zero temperatures, and even when controlling humidity at higher room temperatures, it does not generate the large amount of drainage that conventional methods do, so it can be done with a small amount of humidification. There is an effect.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an example of an apparatus used to implement the method of the present invention. FIG. 2 is an explanatory diagram showing the structure of the refrigerant heater of FIG. 1. FIG. 3 is an explanatory diagram showing another embodiment of the refrigerant heater.

Claims (1)

[Scope of Claims] A constant temperature air supply machine including a refrigerant evaporator of a refrigerator as an air cooler and an air heater provided on the lee side of the refrigerant evaporator in an air flow path equipped with a blower; In an apparatus comprising the constant temperature air supply device and a constant temperature and humidity chamber connected to form a series of air circulation channels, the refrigerant is heated at an appropriate location in the refrigerant flow path from the refrigerant expander to the refrigerant evaporator of the refrigerator. A device is provided so as to be able to heat the refrigerant flowing into the refrigerant evaporator, so that the air passing through the refrigerant evaporator reaches the dew point temperature of air having temperature and humidity conditions that are the target values of the constant temperature and humidity chamber. A constant temperature system characterized by operating a refrigerant heater to adjust the cooling capacity of the refrigerant evaporator, heating the air that has passed through the refrigerant evaporator to the target temperature with the air heater, and supplying the heated air to the constant temperature and humidity chamber. How to supply constant humidity air.