JPH0350180B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is applicable to freezing equipment that uses outdoor air and indoor air, such as a ventilation system that supplies and exhausts indoor and outdoor air via a heat exchanger. This invention relates to a prevention device.

[Conventional technology]

Figures 8 to 11 are for example
8 is a longitudinal sectional view, FIG. 9 is an enlarged perspective view of the end of the heat exchanger, and FIG. 10 is a configuration diagram. FIG. 11 is an explanatory diagram of freezing.

In the figure, 1 is the main body of the ventilation system as a device that uses indoor air and outdoor air, 2 is the outer box of main body 1,
2a is an outside air intake port provided on the side of the outer box;
2c is the same air inlet, 2d is the same air outlet, and 3 is a heat exchanger housed in the outer box 2, which is connected to a large number of corrugated plates 3a for heat conductivity or moisture permeability. The corrugated plates 3a are formed into a prismatic shape by alternately stacking a large number of heat-resistant flat plates 3b and inserting the corrugated plates 3a with their corrugation forming direction changed by 90 degrees. It is placed on its side and tilted at a 45 degree angle. 4 is heat exchanger 3
an air filter installed on the inlet side of the supply air;
5 is an air filter also installed on the inflow side of exhaust air, 6 is a supply air blower installed on the outflow side of the supply air of the heat exchanger 3, and 7 is an exhaust air blower installed on the outflow side of exhaust air. Blower, A is supply air flow, B
is the exhaust flow.

The conventional heat exchange type ventilation system is configured as described above, and outside air is supplied to the air supply blower 6 as shown by airflow A.
Due to the rotation of , the air is sucked in through the suction port 2a, passes through the air filter 4 and the heat exchanger 3, and is blown out from the air outlet 2b into the room. In addition, the indoor air is airflow B
As shown in the figure, as the exhaust blower 7 rotates, air is sucked in through the suction port 2c, passes through the air filter 5 and the heat exchanger 3, and is blown out from the air outlet 2d. In this way, heat exchange takes place between the supply air and the exhaust air.

[Problem that the invention seeks to solve]

In the heat exchange type ventilation system as described above, when this ventilation system is used in a cold region, the supply air flow A is generally
becomes a low-temperature airflow, and the exhaust flow B becomes a high-temperature airflow.
When the supply air flow A is at a low temperature (-5°C or lower), the exhaust flow B is cooled by the supply air flow A in a portion 3A near the inlet of the heat exchanger 3, so that condensation, frost, or ice formation does not occur. occurs. Therefore, the heat exchanger 3 becomes clogged and the exhaust stream B no longer flows near it. As a result, there is no heat exchange in the vicinity of part 3A, so
Next, the vicinity of the adjacent portion 3B will be cooled the most by the air supply flow A, and ice will form. Therefore, if the operation continues in this state, the portion adjacent to portion 3B will begin to freeze, and eventually the entire surface will freeze, and exhaust gas and heat exchange will no longer occur.

In order to prevent such ice formation and the resulting functional deterioration, if the heat exchanger 3 becomes frozen, a temperature detector and a timer are used to intermittently stop the supply air blower 6. Only the exhaust blower 7 is operated to melt the formed ice. However, in this case, the following problem occurs.

(a) If only exhaust operation is used, the indoor air balance will be disrupted and air will be sucked in from elsewhere in the room, causing cold air to enter.

(b) As a result of the above, there is a risk of abnormal combustion in exhaust-type combustion appliances (pot-type kerosene stoves, gas furnaces, etc.) due to the negative pressure inside the room.

(c) If part 3A in Figure 11 is clogged with ice, indoor air cannot pass through it, so heat is not applied and the ice does not melt sufficiently.

In addition, as another means, a heating element is provided on the low temperature air (outside air) side to preheat the low temperature air to a temperature (0° C. or higher) at which ice does not form on the heat exchanger 3. However, this requires a lot of energy. For example, indoor temperature is 20℃, outside temperature is -
Assuming 15℃ and ventilation airflow rate of ^500m3 /hour, to raise the temperature of -15℃ air to 0℃, the weight of the air must be 1.2Kg/hour.
m ³ , 15 x 0.24 x 500 x 1.2 = 2160 Kcal/hour of heat is required, and to raise the temperature with a heating element, approximately
2.5KW/hour of power is required. This is a larger value than the amount of heat exchanged with air heated to 0°C (2016 Kcal/hour) when the temperature exchange efficiency of this device is 70%, and the energy saving efficiency becomes worse.

In this way, a lot of energy is required to prevent the heat exchanger 3 from being degraded or damaged due to freezing. Furthermore, if only exhaust operation is performed and the ice in the heat exchanger 3 is melted using the heat of the indoor air, it is difficult to completely melt the ice, and the indoor pressure becomes negative during defrosting operation. However, there are other problems such as the intrusion of cold air and abnormal combustion of indoor combustion appliances.

This invention was made in order to solve the above-mentioned problems, and an object of the present invention is to provide an anti-freeze device that can melt ice with less energy even under low-temperature conditions where the heat exchanger is frozen. do.

Another object of the present invention, in addition to the above object, is to provide an antifreeze device that can automatically perform an accurate defrosting operation.

[Means for solving problems]

The antifreeze device for a ventilation system according to the present invention has a low-temperature air inlet for introducing outside air and a high-temperature air inlet for introducing indoor air into a box wall surface, and a and an air outlet for supplying outdoor air, and an air flow path is provided in the box body, and the air flow path is provided in the air flow path to selectively close the low temperature air inlet and the high temperature air inlet. It is equipped with a damper and a heating element that is provided near the air outlet of the air flow path and heats the air in the air flow path.

Further, in the antifreezing device for a ventilation system according to another aspect of the present invention, in the above device, a temperature detection device is provided near the low temperature air inlet to detect the temperature of the outside air, and is activated when the temperature of the outside air is detected to be a predetermined low temperature. A control device is provided which gives a command to the damper to close the low-temperature air inlet at regular intervals when the temperature detector and the temperature detector operate, and also energizes the heating element at regular intervals.

[Effect]

In this invention, the low-temperature air inlet is closed by the operation of the damper, and the high-temperature air inlet is opened to introduce high-temperature air, which is then heated by the heating element and supplied from the air outlet.

In another aspect of the present invention, when the outside air temperature reaches the freezing temperature, high temperature air is intermittently introduced, heated and supplied.

〔Example〕

Figures 1 to 5 are diagrams showing an embodiment in which the present invention is used to prevent freezing of a simultaneous air supply and exhaust type ventilation system. Figure 1 is a block diagram of only the anti-freeze system, and Figure 2 is A configuration diagram when used in a ventilation system, FIG. 3 is an operation explanatory diagram, and FIGS. 4 and 5 are characteristic curve diagrams.
6, 7, A, and B are similar to the conventional device described above.

In the figure, numeral 9 denotes a box disposed on the suction side of the main body 1, and an air flow path is formed inside. 9a is a low-temperature air inlet provided in the box body 9 and opens to the outside air, 9b is a high-temperature air inlet that also opens to the indoor side, and 9c is an air outlet.
is connected to the suction port 2a of the main body 1. 10 is a damper pivotally mounted on the box body 9 and opens and closes the air inlet ports 9a and 9b; 11 is a heating element provided near the air outlet port 9c of the box body 9. 17 is a drive mechanism for the damper 10.

In the antifreeze device for a ventilation system configured as described above, the damper 10 normally opens the low temperature air inlet 9a and closes the high temperature air inlet 9b, as shown in FIG. Therefore, as shown by airflow A, low-temperature air enters the box 9 from the low-temperature air inlet 9a, and is supplied to the main body 1 from the air outlet 9c through the suction port 2a. The subsequent operation is the same as the conventional one.

Next, when the low temperature air temperature is low and ice forms on the heat exchanger 3, the damper 10 rotates, and as shown in FIG. 3, the low temperature air inlet 9a is closed and the high temperature air inlet 9b is closed. It will be released. At the same time, heating element 1
1 is energized. Although the damper 10 is driven by an electric motor (not shown), it may also be driven manually. Furthermore, if the exhaust blower 7 is stopped at this time, outside wind can be prevented from entering. The high-temperature air then enters the box body 9 through the high-temperature air inlet 9b, is heated by the heater 11, and is supplied to the low-temperature side flow path of the main body 1 through the air outlet 9c. As a result, high-temperature air flows through the flow path in which low-temperature air normally flows in the heat exchanger 3, and the ice formed in the high-temperature side flow path is melted.

After the ice melts, the damper 10 rotates in the opposite direction to the state shown in FIGS. 1 and 2, and at the same time, the power to the heating element 11 is cut off.

Figure 4 shows a curve 12 representing the relationship between the indoor temperature and the time until freezing starts when the outside air temperature is -15°C, and a curve representing the relationship between the time until the air volume decreases by 30% in the apparatus of this example. 13 is shown. Also,
Figure 5 shows the time it takes to completely melt the ice by switching to thawing operation when ice has formed to the extent that the air flow rate has decreased by approximately 30%, and the air supplied to the low-temperature side flow path of the heat exchanger 3 during thawing operation. shows the relationship between temperature and temperature.

As is clear from Figures 4 and 5, indoor temperature does not have a large effect on the onset of freezing or the time it takes for the air volume to drop by 30%, but when used to melt ice on the heat exchanger 3, Thawing time has a large effect. Therefore, if the temperature of the air supplied to the heat exchanger 3 is raised to 20° C. or higher using the heater 11, ice can be melted in a short time.

As an example, room temperature is 10℃, processing air volume is ^500m3 /hour,
Considering a device with heat exchange efficiency of 70%, the air volume is 30%.
If thawing operation is started after the % drop, it will take about 12 minutes to thaw, and during this time the exhaust blower will be stopped and circulation operation will take place, so ventilation will not be possible, or only exhaust will be available, making it impossible to provide sufficient ventilation. Here,
When a 2KW heating element 11 is installed and energized, indoor air at 10°C is heated to 22°C and supplied to the heat exchanger 3, making it possible to defrost the air within 4 minutes. In this case, the power consumption is 0.081KW/hour when the power is turned on for 4 minutes once every hour and 30 minutes, making it possible to operate with much less power than the conventional preheating type.

Also, during thawing operation, the exhaust blower 7 is stopped in conjunction with the ventilation system, the damper 10 is switched, the heating element 11 is energized, and the high temperature flow path is narrowed to reduce the amount of air in the supply air flow path. If the capacity of the heating element 11 is the same as that of the conventional device, the thawing time will be shortened, and the ventilation stop time can be shortened. The amount of air blown at this time may be controlled by changing the capacity of the blower motor or by changing the area of the air duct.

FIGS. 6 and 7 are configuration diagrams of a damper portion showing another embodiment in which the present invention is applied to a ventilation system similar to the above embodiment.

In FIG. 6, a temperature detector 15 is installed in the low temperature air inlet 9a to detect the temperature at which the heat exchanger 3 freezes (preset). Damper 1
0, the heating element 11 is energized, and after this state is maintained for a certain period of time, the damper 10 is switched to normal operation, and the heating element 11 is de-energized. This operation can be repeated intermittently at predetermined time intervals. As a result, accurate defrosting operation is automatically performed.

FIG. 7 shows the temperature detector 15 in FIG.
It is placed upstream of the damper 10 in a position where it can detect the high temperature air temperature when the damper 10 is in operation, and detects the indoor temperature when the thawing operation starts. When the temperature is such that it can be thawed in a short time, the heating element 11 is not energized. This saves power when the indoor temperature is high, and saves energy at other times.

Furthermore, although the damper 10 has been described as a single plate-like structure, other types of mechanisms (slide type, butterfly type) may be used as long as the damper 10 can open and close the low-temperature air inlet 9a and the high-temperature air inlet 9b, respectively. .

In each of the above embodiments, a cross-flow type heat exchanger 3 is used, but a rotating type, a counter-flow type, etc. can be similarly applied.

In addition, although the example described a ventilation device,
It can also be applied to other equipment such as air conditioners that use indoor air and outdoor air.

〔Effect of the invention〕

As explained above, the present invention has the effect of melting ice that occurs in a short period of time when a device that uses outdoor air and indoor air, such as the heat exchange type ventilation device, is used under low-temperature conditions.

Further, in another invention of the present invention, a temperature detector is provided to detect the outside air temperature, and when the temperature detector detects a predetermined temperature, the damper is operated at regular intervals and the heating element is energized. This has the effect of automatically performing a defrosting operation.

[Brief explanation of drawings]

Figures 1 to 5 are diagrams showing an embodiment of the antifreeze device for a ventilation system according to the present invention, in which Figure 1 is a configuration diagram, and Figure 2 is a configuration diagram when applied to a ventilation system.
FIG. 3 is an explanatory diagram of the operation, FIG. 4 is a freezing time characteristic curve diagram, FIG. 5 is a melting time characteristic curve diagram, and FIGS. 6 and 7 are configurations of the damper portion showing other embodiments of the present invention. Figures 8 to 11 are diagrams showing conventional heat exchange type ventilation equipment, with Figure 8 being a longitudinal sectional view and Figure 9 being a longitudinal sectional view.
The figure is an enlarged end view of the heat exchanger, Figure 10 is a configuration diagram,
FIG. 11 is an explanatory diagram of freezing. In the figure, 1 is the main body of the ventilation system, 2a is a low temperature air inlet, 2c is a high temperature air inlet, 3 is a heat exchanger, 9
is a box body, 9a is a low temperature air inlet, 9b is a high temperature air inlet, 9c is an air outlet, 10 is a damper, 11
15 is a temperature detector, and 16 is a control device. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A low-temperature air inlet 9a for introducing outside air and a high-temperature air inlet 9 for introducing indoor air into the wall of the box 9.
b, and an air outlet 9c for supplying outdoor air or indoor air to the equipment 1 that uses outdoor air and indoor air. A damper 10 is provided to selectively close the low-temperature air inlet 9a and the high-temperature air inlet 9b, and a damper 10 is provided near the air outlet 9c of the air flow path to heat the air in the air flow path. An anti-freezing device comprising a child 11. 2 On the wall of the box body 9, a low temperature air inlet 9a that introduces outside air and a high temperature air inlet 9 that introduces indoor air
b, and an air outlet 9c for supplying outdoor air or indoor air to the equipment 1 that uses outdoor air and indoor air. a damper 10 that is provided to selectively close the low-temperature air inlet 9a and the high-temperature air inlet 9b, and a heater that is provided near the air outlet 9c of the air flow path to heat the air in the air flow path. child 11 and the low temperature air inlet 9
a temperature detector 15 that is installed near a and detects the temperature of the outside air and operates when a predetermined low temperature is detected;
When the temperature detector 15 operates, it gives a command to the damper 10 to close the low-temperature air inlet 9a at regular intervals, and also closes the heating element 11.
An anti-freeze device comprising a control device 16 that energizes the device at regular intervals.