JPS63271051A - Method and apparatus for preventing condensation - Google Patents

Abstract

PURPOSE:To prevent occurrence of condensation by a method wherein means for reducing humidity of atmosphere is operated when a calculated temperature difference subtracting a frost point from a measured temperature value is not higher than a predetermined temperature for preventing frost. CONSTITUTION:An electronic type dew point and frost point meter 1 is provided with an outer temperature sensor 3 and a stored humidity sensor 5. The outer temperature sensor 3 is positioned to be contacted with a window pane or near the window pane. The electronic dew point and frost point meter 1 stores a digital calculation processing program so as to calculate a frost point Ttheta from a relative humidity H and a temperature T. A temperature difference of (a glass surface temperature-an approximate condensation point at the glass surface) is calculated and this calculated temperature difference is compared with a predetermined temperature difference selected from a range of 1.5-3 deg.C, for example. In case the calculated temperature difference is judged as one not higher than the predetermined temperature difference (for example, 2 deg.C), means for reducing an atmospheric humidity is operated. As the means for reducing the atmospheric humidity, a ventilation fan 7 can be applied. In case the calculated temperature difference is not higher than the predetermined temperature difference through a control means 8, the ventilation fan 7 is operated and in turn if the calculated temperature difference exceeds the predetermined temperature difference, the ventilation fan is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for preventing dew or frost formation.
In particular, the present invention relates to a method and apparatus for preventing dew or frost from forming on linen glass, wall surfaces, etc. in general residences, etc., using an electronic dew point/frost point meter. The present invention is applicable not only to rooms, bathrooms, and basements of ordinary residences, but also to buildings, warehouses, and other structures, frozen and refrigerated showcases, automobile rear windows, and home VTRs.
, Optical devices that use lenses, such as laser measuring instruments, etc. In applications where condensation (frost) is averse and the atmospheric humidity can be controlled, by controlling the atmosphere before condensation (frost) occurs, rather than after it occurs. ,condensation(
frost) can be prevented.

Prior art and its problems A method for preventing binding using a ventilation fan for bathrooms and living rooms is known. This system uses a condensation sensor to constantly monitor the occurrence of condensation, and when it detects that the indoor humidity has increased and condensation has occurred indoors, it automatically operates the ventilation fan for the required operating time (approximately 30 minutes to 3 hours). After the operation is completed, the sensor monitors condensation again. However, this method does not truly prevent condensation because it detects condensation after it has occurred and activates the ventilation fan.2 The condensation sensor takes a long time to recover from condensation. Furthermore, although it is a device that detects dew condensation, it has the fatal drawback of being susceptible to condensation or high humidity due to its structure, and shortening its lifespan if exposed to these.

Purpose of the Invention The present invention, unlike the prior art, eliminates condensation (frost) in the true sense of the word.
The purpose is to prevent the occurrence of dew condensation (frost).

Summary of the Invention Toward the above objective, the inventors of the present invention have conducted repeated studies and have come up with the idea of successfully applying a recently developed electronic dew point/frost point meter (referred to as a dew/frost module) and a moisture-proof sensor probe. did. The dew point of a certain atmospheric air means the temperature at which the water vapor pressure becomes saturated water vapor pressure. An electronic dew point/frost point meter is a device that calculates and displays the dew point or frost point from a predetermined calculation formula based on the measured relative humidity and temperature. The frost point is the temperature when the water vapor pressure in the measurement atmosphere is equal to the saturated vapor pressure in equilibrium with ice at that temperature. In other words, the only difference between dew point and frost point is whether they are referring to the equilibrium state with water or the equilibrium state with ice.

Therefore, the frost point is calculated from relative humidity and temperature measurements in the same way as the dew point. Taking the example of preventing dew condensation on window glass in a living room, if the glass surface temperature is always above the dew (frost) point of the atmosphere in contact with the glass surface, no condensation (frost) will occur. By using the above-mentioned electronic dew point/frost point meter as part of the external temperature sensor set, it is possible to separately perform (1) measuring the temperature on the glass surface and (11) detecting the relative humidity in the room near the glass window. This makes it possible to obtain a correct temperature value on the glass surface and a highly accurate near-black value on the glass surface. Since the temperature sensor is relatively resistant to humidity (condensation), there is no problem in placing it in direct contact with the window glass (or as close as possible if this is not allowed). Humidity sensors can maintain a long lifespan by placing them away from window glass so that they are not affected by condensation, and humidity does not vary as much depending on the installation location as temperature does. In this way, the calculation of (glass surface temperature - proximal (box) point on the glass surface) = ΔT can be conveniently and accurately performed. If the calculated ΔT becomes smaller than the set temperature difference, a humidity reducing means such as a ventilation fan is activated to prevent condensation from occurring. It is preferable that the operation and stopping of the humidity reducing means be controlled in two or more stages.

Based on the above findings, the present invention provides the following methods: 1) (a) Measuring the temperature of the area where condensation or frost is prevented in the atmosphere and at the same time measuring the relative humidity near the area where condensation or frost is prevented in the atmosphere; ) calculating an approximate chain point or frost point of the region from the measured temperature value and the measured relative humidity value; (c) calculating a temperature difference by subtracting the calculated approximate dew point formula or frost point from the measured temperature value; b) When the calculated temperature difference becomes less than the set temperature difference for preventing condensation or frost, the atmospheric humidity reducing means is activated, and the calculated temperature difference sets the set temperature difference or another set temperature difference higher than the set temperature difference. 2) a method for preventing condensation or frost formation that includes stopping the operation of an atmospheric humidity reducing means when the temperature exceeds the external temperature An electronic dew point/frost point meter that is equipped with a sensor and a humidity sensor that measures the relative humidity near the area where condensation or frost formation is prevented, and which is capable of calculating an approximate dew point or frost point of the area where condensation or frost formation is prevented. , a determiner for determining the magnitude of a calculated humidity difference obtained by subtracting the calculated approximate dew point or frost point from the temperature measured by the external temperature sensor and a set temperature difference for preventing dew or frost; an atmospheric humidity reducing means; A dew condensation or frost prevention device is provided, which includes a control means for controlling activation and stop of the atmospheric humidity reduction means according to a judgment of a device.

FIG. 1 shows a specific example in which the present invention is applied to prevent condensation in a living room of a general residence. The indoor atmosphere tends to cause dew condensation on the window glass W, which is cooled by the outside air.

According to the invention, an electronic dew point/frost point meter 1 is installed indoors. The electronic dew point/frost point meter 1 is commercially available as a dew/frost module. It comprises an external temperature sensor 3 and a built-in humidity sensor 5.

The external temperature sensor 3 is positioned in contact with the window pane or, when this is not possible, as close as possible to the window pane. The temperature sensor 3 needs to measure the actual temperature of the window glass itself, or even when this is not possible, a temperature that is very close to the actual temperature. A thermistor is generally used as a temperature sensor.

As the humidity sensor 5, a large number of humidity sensing elements have been developed in recent years, and any of them can be used.
Zirconia, Ittria + Zirconia or C
A moisture sensing element constructed by sintering a ceramic containing a stabilizer such as aO or MgO on a patterned electrode formed on a substrate is excellent in terms of robustness and operational stability. Humidity sensors have low resistance to condensation or high humidity, so the dew point and
It is a good idea to install a frost point meter. There is a large difference in temperature between indoors and on the window glass, but humidity does not change that much, so
There is no problem even if the humidity sensor is moved slightly away from the window glass. However, the error decreases as the humidity sensor is placed as close to the window glass as possible.

Electronic dew point/frost point meters consist of an electronic circuit and a sensor in the detection section, but unless the circuit system is moisture-proof, it cannot be used stably for a long period of time in an atmosphere with relative humidity of 80% or higher. .

For this reason, a method of connecting to the electronic dew point/frost point meter on the main body via a sensor probe that includes part of the circuit system and a sensor in the detection section is considered. An example of the structure of the sensor probe 2 is shown in FIG. Since the circuit system incorporates a part of the electronic dew point/frost point meter circuit, this part is sufficiently sealed against moisture, and part of the sensor is exposed to the outside air.

In this case, the sensor position is such that the temperature sensor is placed in contact with or in close proximity to a region for preventing dew or frost formation in the atmosphere. Further, the humidity sensor is placed near the area where dew or frost is prevented from forming in the atmosphere.

Electronic dew point/frost point meters are characterized by having both a calculation function that calculates the dew (frost) point based on the measured temperature and relative humidity, and a display function that digitally displays them. A simple explanation of the principle of operation: The relationship at phase equilibrium between liquid and gas is generally given by the Kura-Iron equation.

However, λ: latent heat of evaporation, υ1, υ2: volume in liquid or gas, P: vapor pressure.

If λ is constant with respect to temperature and Equation 1) is integrated, λMP = ee RT-(2). However, M: molecular weight, R: gas constant, and C: integral constant. Since equation (2) is an approximate equation, in reality, two points (P, , TI
), (Ps□, T2) into equation (2) (9.
205.283) (92,56,312) (unit mmH
g ), then Ps: t 162 X 10' exp (-s27
a, "r) - - - - - (3), and the conversion formula for the saturated water vapor pressure and temperature of water can be found. The value found by equation (3) is the value of the saturated water vapor pressure found experimentally. There is no big difference.

Next, if the relative humidity measured by the humidity detector is H and the water vapor pressure of the measurement atmosphere is P, then between the two, H=-X100 (a)... (4) P
.

Since there is this relationship, P=PsXH/100 (5). Since the dew point TD of the measurement atmosphere indicates the temperature T at which the water vapor pressure P of the measurement atmosphere should reach the saturated water vapor pressure,
When replacing P, →pS'r-+'rD in equation (3), TD=-5278/1h(P/1.162X109'
)...(6). Expression P, ), (5) can be transformed into (6
), then T, = -5278/I n(top exp
(-5278/T) )""" (7). Using equation (7), if you know the relative humidity H and temperature T, you can find the dew point TD. The TD obtained from equation (7) is the actual value. There are almost no errors.

When the water vapor pressure in the measurement atmosphere is equal to the saturated water vapor pressure in equilibrium with ice at a certain temperature, that temperature is called the frost point of the gas. In other words, the difference between the dew point and the 26 point lies in whether they are referring to an equilibrium state with water or an equilibrium state with ice. Therefore, if we rewrite the above relational expressions (3) to (7) at a temperature equal to the saturated water vapor pressure in equilibrium with ice, we can use the same method to calculate the frost point T from the measured values of H and T.
Find D.

The electronic dew point/frost point meter has a built-in digital calculation processing program and calculates the dew (frost) point Tθ from the relative humidity H and temperature T. In this specific example, the temperature T is the temperature of the glass window (or its vicinity), and the relative humidity H can also be closely approximated to the value of the atmosphere in contact with the glass window, so the calculated dew (frost) point T
θ gives a good proximal (frost) point on the glass surface.

If the glass surface temperature can be maintained above the atmospheric dew (frost) point on the glass surface at all times, condensation (frost) will not occur in principle. Therefore, in the present invention, (glass surface temperature -
The temperature difference (approximate dew point on the glass surface) is calculated, and the calculated temperature difference is compared with a set temperature difference selected from a range of 1.5 to 3° C., for example.

For example, if the set temperature difference is 2°C, the calculated temperature difference is 2°C.
The magnitude relationship between the two is determined. If the calculated temperature difference is greater than 2°C, there is some margin before condensation occurs, but if the calculated temperature difference is greater than 2°C,
When the temperature drops below ℃, condensation is imminent and preventive measures must be taken immediately. In this case, a decision device that makes such a decision is built into an electronic dew point/frost point meter.

When it is determined that the calculated temperature difference is less than or equal to a set temperature difference (for example, 2° C.), the atmospheric humidity reducing means is activated. As the atmospheric humidity reducing means, the optimal means for dehumidification is selected depending on the target atmosphere.

In this example, it is the ventilation fan 7. It is preferable to use a heat exchange type ventilation fan to keep the room temperature from dropping. The judgment output signal from the judgment device is sent via the control means 8 to drive the ventilation fan 7 when the calculated temperature difference is less than or equal to the set temperature difference, and to stop the ventilation fan 7 when the calculated temperature difference exceeds the set temperature difference. As the control means 8, an appropriate relay circuit or the like may be used.

A more preferable method of driving a ventilation fan is to use two-step temperature settings. The ventilation fan is commanded to stop based on a set temperature difference (eg, 4° C.) selected from 3 to 5° C., which is higher than the above set temperature difference (eg, 2° C.). In this case, when the calculated temperature difference becomes 2° C. or less, the ventilation fan is activated, and when the calculated temperature difference becomes 4° C. or more, the ventilation fan is stopped. Ventilation fans operate until temperatures below 2°C to 4°C. By doing this,
Condensation (frost) can be prevented more stably and safely than in the case of a single temperature difference setting method.

In addition, if a large-scale building is equipped with multiple ventilation fans or ventilation/air systems that can output water at multiple rotation speeds, setting two or more temperature differences will allow for even more precise control. Control can be done.

In Figures 1 and 2, the designation ``6. D J, ``8.0'' illustrates the approximate dew point of the glass surface and the [[
1o and oJ illustrate the temperature of the glass surface. Such digital displays are convenient in that they provide information to residents. Reference number 9 indicates a power source.

FIG. 3 shows an operation flowchart of the above specific example.

The above example uses a residence, but as mentioned at the beginning, the present invention has many other applications. For example, in the case of a frozen/refrigerated showcase, if condensation occurs, the contents become invisible, so it is effective to apply the dew condensation prevention measures of the present invention. In this case, a ventilation fan or an air conditioner is used as the humidity reducing means. The present invention can also be used in the rear window of an automobile. In this case, a glass heat wire controller or a heater is used as the humidity reduction means.

In addition, in optical instruments such as laser measuring instruments, dew condensation may occur on lenses under the environment in which they are used. In this case, the present invention can be applied by using a hot air blower or a dehumidifier as a means for reducing atmospheric humidity. The present invention is based on dew condensation (
Item 1 is equally applicable in situations where material damage, mold, etc. are likely to occur, or malfunctions are likely to occur due to the occurrence of air pollution, and if the atmosphere can be controlled.

Embodiment A dew/frost module (DFM-oo) as shown in FIG.
1) and a moisture-proof sensor probe (SP-001) were used to prevent condensation in the living room. The outside air was -5°C, the inside temperature was 20°C and the relative humidity was 60%. The external thermistor was mounted above the window. The module was installed a little away from the window.

As shown in Figures 4 and 5, the glass surface temperature was 10°C, and the module dew point reading was 8.5°C. An error occurs because the humidity sensor is far from the glass surface, but this does not interfere with the condensation prevention operation, and this error can be reduced by moving the humidity sensor closer to the glass.

Using a single setting method with a set temperature difference of 2°C or less and a two-step setting method with a set temperature difference of 2°C and 4°C, the effectiveness of preventing condensation was confirmed while driving and stopping the ventilation fan. No condensation occurred, and condensation was prevented very effectively.

Effects of the Invention A true dew condensation (frost) prevention effect that prevents condensation N (frost) can be realized efficiently and stably without causing deterioration of the humidity sensor.

1 and 2 are explanatory diagrams showing an example of preventing dew condensation in a residence as one of the application examples of the present invention, FIG. 3 is a flowchart of the method of the present invention, and FIG. A graph showing the relationship between relative humidity and electrical resistance value, and the fifth
The figure is also a graph showing the relationship between temperature and dew point under several relative humidities.

1: N, child type dew point frost point meter 2: Moisture-proof sensor probe 3: Temperature sensor 5: Humidity sensor 7: Ventilation fan 8: Control means 9　2　It　source Figure 4 Gamo True and Ji No su　degreeyu Table production 1 Skin surface Inspection The Snake

Claims (1)

[Scope of Claims] 1) (a) Measuring the temperature of the dew condensation or frost prevention area in the atmosphere and at the same time measuring the relative humidity near the dew or frost prevention area in the atmosphere; (b) the measured temperature value and Calculating the approximate dew point or frost point of the area from the measured relative humidity value; (c) calculating a temperature difference by subtracting the calculated approximate dew point or frost point from the measured temperature value; (d) determining whether the calculated temperature difference is condensation. Alternatively, the atmospheric humidity reducing means is activated when the temperature difference falls below the set temperature difference for frost prevention, and the atmospheric humidity reducing means is activated when the calculated temperature difference exceeds the set temperature difference or another set temperature difference higher than the set temperature difference. A method of preventing condensation or frost that includes stopping. 2) an external temperature sensor disposed in contact with or close to a condensation or frost prevention area in the atmosphere; and a humidity sensor that measures the relative humidity near the dew or frost prevention area in the atmosphere; An electronic dew point/frost point meter capable of calculating the approximate dew point or frost point of the dew or frost prevention area; and a calculated temperature difference obtained by subtracting the calculated approximate dew point or frost point from the temperature measured by the external temperature sensor. It includes: a determiner that determines the magnitude of the difference from a set temperature difference for preventing dew or frost; an atmospheric humidity reducing means; and a control means that controls activation and stop of the atmospheric humidity reducing means in accordance with the determination of the determining device. Condensation or frost prevention device.