JPH0519692Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Industrial application field] This invention is used to prevent freezing of equipment that uses outdoor air and indoor air, such as ventilation systems that supply and exhaust air through a heat exchanger. This relates to rainwater covers used in

[Prior Art] Figs. 6 to 9 are diagrams showing a conventional heat exchange type ventilation device similar to that shown in, for example, Japanese Utility Model Publication No. 54-42125, in which Fig. 6 is a longitudinal sectional view; FIG. 7 is an enlarged perspective view of the end face of the heat exchanger, FIG. 8 is a configuration diagram, and FIG. 9 is an explanatory diagram of freezing.

In the figure, 1 is the main body of a ventilation system, which is an example of equipment that uses outdoor air and indoor air, and 2 is the main body 1.
2a is the outside air inlet provided on the side of the outer box 2, 2b is the same outlet, 2c is the same indoor air inlet, 2d is the same outlet, 3 is the outer box 2
In the heat exchanger housed in the heat exchanger, a large number of corrugated plates 3a and a large number of flat plates 3b having heat conductivity or moisture permeability and heat conductivity are alternately laminated, and the corrugated plates 3a are alternately stacked in the corrugated direction. It is formed into a prismatic shape by inserting it at an angle of 90 degrees, and is installed in the center of the outer box 2 horizontally and tilted at 45 degrees. 4 is an air filter installed on the intake air side of the heat exchanger 3, 5 is an air filter also installed on the exhaust air intake side, and 6 is installed on the intake air outlet side of the heat exchanger 3. A supply air blower, 7 is an exhaust blower also installed on the outflow side of exhaust air, A is a supply air flow, and B is an exhaust flow.

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

[Problem that the invention attempts to solve]

In the conventional heat exchange type ventilation system as described above, when the ventilation system is used in a cold region, the supply air flow A generally becomes a low temperature air flow, and the exhaust flow B becomes a high temperature air flow. When the air supply flow A is at a low temperature (-5°C or lower), the exhaust air flow B is cooled by the air supply flow A in a portion 3A of the heat exchanger 3 near the inlet of the air supply flow A, so that dew condensation and Frost or ice formation 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 the portion 3A, and the vicinity of the adjacent portion 3B is then cooled the most by the air supply flow A, causing ice to 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 heat-burning appliances (pot-type kerosene stoves, gas furnaces, etc.) due to the negative pressure inside the room.

(c) If part 3A in Figure 9 is clogged with ice, indoor air will not pass through it, so heat will not be applied and the ice will 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.
^m3 , 15 x 0.24 x 500 x 1.2 = 2.160 Kcal/hour of heat is required, and to raise the temperature with a heating element, approximately
2.5KW/hour of power is required. This value is larger than the amount of heat exchanged with air heated to 0°C, which is 2.016 Kcal/hour, when the temperature exchange efficiency of this device is 70%, and the energy saving efficiency is also poor.

Furthermore, in cases where the supply air blower 6 and the exhaust air blower 7 are driven by one electric motor, it is impossible to operate only one of them.

As described above, when a heat exchange type ventilator is used under low temperature conditions, ice forms on the heat exchanger 3, leading to performance deterioration and damage, but it takes a lot of energy to prevent this. Furthermore, when thawing frozen ice, there are various problems such as the intrusion of outside wind. There is also the problem that defrosting operation may not be possible depending on the configuration of the blower.

This idea was devised to solve the above problem, and was designed to remove ice that forms when equipment that uses outdoor air and indoor air, such as heat exchange ventilation equipment, is used in low-temperature conditions. To provide a rainwater cover which is melted with little energy without causing outside wind to enter inside.

[Means for solving problems]

The rainwater cover according to this invention is provided with a low-temperature flow path that supplies low-temperature air and a high-temperature flow path that exhausts high-temperature air in a box placed outdoors, and each of the flow paths has a disconnection between these flow paths. A damper that adjusts the area, a heater that heats the low-temperature air flowing through the low-temperature flow path,
A temperature detector is provided to detect the temperature of the low-temperature air flowing through the low-temperature flow path, and when the temperature detector detects a temperature lower than a predetermined temperature, the damper is moved between the low-temperature flow path and the high-temperature flow path. The heating element is equipped with a control device that switches to reduce the cross-sectional area and intermittently performs a defrosting operation in which the heating element is energized.

[Effect]

In this device, when the temperature detector detects that the temperature of the low-temperature air flowing through the low-temperature flow path has fallen below a predetermined temperature, the control device intermittently (every predetermined time) causes the damper to move into the low-temperature flow path. Then, the cross-sectional area of the high-temperature flow path is reduced and a thawing operation is started in which the heater is energized, so the amount of air supplied to the equipment is intermittently reduced, the low-temperature air is heated, and the equipment is thawed.

〔Example〕

Figures 1 to 5 are diagrams showing one embodiment of this invention when applied to a heat exchange type ventilation system as a device that uses outdoor air and indoor air.
The figure is a configuration diagram, and Figure 2 is a plan sectional view of the damper part.
FIG. 3 is a side sectional view of FIG. 2, and FIGS. 4 and 5 are characteristic curve diagrams.
3A, 3B, 6, 7, A, and B are similar to the conventional device described above. However, the positions of the suction ports 2a, 2c, the blower ports 2b, 2d, and the blowers 6, 7 are opposite to each other.

In the diagram, 9 is a rainwater cover installed outdoors;
A and 9B are a low temperature flow path and a high temperature flow path formed inside the box body of the rainwater cover 9, and 9a is a low temperature flow path (outside air) inlet provided on the side surface of the low temperature flow path 9A and is open to the outdoors. 9b is the same outlet, and 9c is the high temperature flow path 9.
High temperature flow path (exhaust) inlet provided on the side of B, 9
Similarly, the exit d is open to the outdoors. The low-temperature flow path outlet 9b communicates with the suction port 2a of the main body 1, and the high-temperature flow path inlet 9c similarly communicates with the air outlet 2d. 10 is a partition wall that partitions the low temperature flow path 9A and the high temperature flow path 9B, 11 is a damper drive mechanism, and 12 is the low temperature flow path 9.
The damper 13 is pivotally mounted in the high temperature flow path 9B and rotated by the damper drive mechanism 11 to reduce the flow area of the low temperature flow path inlet 9a. A damper that reduces the flow area of the flow path outlet 9d, 14 a heater provided in the low temperature flow path 9A, 18 a temperature detector provided at the low temperature path entrance 9a to detect the temperature of the low temperature air, 1
9, when the temperature detector 18 detects that the temperature (preset) at which ice forms in the heat exchanger 3 has been reached;
This is a control device that controls the defrosting operation by driving the damper drive mechanism 11 and energizing the heating element 14 intermittently.

In the rainwater cover configured as above,
At all times, the damper 12,
13 opens the low temperature channel inlet 9a and the high temperature channel outlet 9d. Therefore, as shown by airflow A, the low temperature air flows from the low temperature flow path inlet 9a to the low temperature flow path 9A.
It is supplied to the main body 1 from the low-temperature flow path outlet 9b through the suction port 2a. Also, high temperature air is airflow B
As shown, from the air outlet 2d to the high temperature flow path inlet 9c.
and enters the high temperature flow path 9B through the high temperature flow path outlet 9d.
is exhausted outdoors. The operation within the main body 1 is similar to that of the conventional device.

Next, when the low-temperature air temperature is low and reaches a preset temperature at which ice formation occurs on the heat exchanger 3, the low-temperature air temperature is detected by the temperature sensor 18, and the control device 19 accordingly A thawing operation is performed for 5 minutes every 5 minutes. That is, the dampers 12 and 13 are rotated by the drive mechanism 11, and as shown by the solid line in FIG.
a and the flow path area of the high temperature flow path outlet 9d are reduced. At the same time, the heating element 14 is energized. with this,
The supply/exhaust air volume is reduced while maintaining balance, and the low-temperature air is heated and supplied to the heat exchanger 3, so the operation is switched to a thawing operation state, and the ice formed on the heat exchanger 3 is melted. Also, although the air volume has decreased,
Ventilation continues, and supply and exhaust are balanced, so there are no problems with outside wind infiltration.

FIG. 4 shows the relationship between the outside air temperature after heating and the time required to thaw the ice in the heat exchanger 3 until the air volume decreases by about 30% in the apparatus of this embodiment. By reducing the air volume with the dampers 12 and 13 and using the heating elements 14 of the same capacity, it becomes possible to increase the outside air temperature after heating up, shorten the time for thawing operation, and reduce power consumption. can be reduced.

Fig. 5 shows a curve 15 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. 16 is shown.

After the ice melts, the dampers 12 and 13 rotate in opposite directions to open the low-temperature channel inlet 9a and the high-temperature channel outlet 9d, and at the same time, the power to the heater 14 is cut off.

As is clear from FIG. 5, the time from when the heat exchanger 3 starts freezing to when the air volume decreases by 30% does not vary greatly depending on the indoor temperature. Air volume 30
By switching to thawing operation and thawing intermittently before the percentage decreases, the ventilation system can be operated continuously at low temperatures without impairing ventilation performance.

In each of the above embodiments, the dampers 12 and 13 are plate-shaped, but they may be of other types (slide type, butterfly type, shutter type), and the dampers 12 and 13 are located at the inlet and outlet of each flow path 9A and 9B. It may be either a partial portion or an intermediate portion.

Further, the heating element 14 may be installed anywhere as long as it is within the low temperature flow path 9A.

Although each of the above embodiments has been described as being used in a ventilation system incorporating the heat exchanger 3, it is similarly applicable to other equipment that uses outdoor air and indoor air, such as an air conditioner.

[Effect of idea]

As described above, according to the present invention, a partition wall is provided that partitions a low-temperature flow path and a high-temperature flow path, and the temperature sensor is installed on one side of the partition wall, and the control device is installed on the other side of the partition wall. It has the advantage of being easy to use and having structural stability.

[Brief explanation of drawings]

Figures 1 to 5 are diagrams showing an embodiment in which this invention is applied to a heat exchange type ventilation system, in which Figure 1 is a configuration diagram, Figure 2 is a plan sectional view of the rainwater cover in Figure 1,
Figure 3 is a side sectional view of Figure 2, Figure 4 is a melting time characteristic curve diagram, Figure 5 is a freezing time characteristic curve diagram, and Figure 6 is a diagram of freezing time characteristic curves.
9 to 9 are views showing a conventional heat exchange type ventilation system, in which FIG. 6 is a longitudinal sectional view, FIG. 7 is an enlarged perspective view of the end face of the heat exchanger, FIG. 8 is a configuration diagram, and FIG. It is an explanatory diagram of freezing. In the figure, 1 is the main body of the ventilation system as a device that uses outdoor air and indoor air, 2a is a low-temperature air inlet, 2d is a high-temperature air outlet, 3 is a heat exchanger, 6 is a supply air blower, and 7 is an exhaust blower, 9 is a rainwater cover, 9A is a low temperature flow path, 9B is a high temperature flow path, 9a is a low temperature flow path inlet, 9b is an exit on the left, 9c is a high temperature air inlet, 9d is an exit on the left, 12 and 13 are dampers. , 14
18 is a temperature detector, and 19 is a control device. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Scope of utility model registration request] A box installed outdoors has a low-temperature channel for introducing outdoor air into equipment that uses air from the outdoors and indoors, and a high-temperature channel for leading indoor air from the equipment to the outdoors. The high-temperature flow path and the low-temperature flow path are provided with dampers that can adjust the cross-sectional resistance of each flow path, and the low-temperature flow path is equipped with a heater that heats the low-temperature air flowing therein. A temperature detector is provided for detecting the temperature of the low-temperature air flowing through the low-temperature flow path, and
In response to detection of a temperature below a predetermined temperature by this temperature sensor,
A rainwater cover comprising a control device that switches the damper to reduce the cross-sectional area of the low-temperature flow path and the high-temperature flow path and intermittently performs a thawing operation of energizing the heating element, wherein the low-temperature flow path and the high-temperature flow path are A rainwater cover characterized in that a partition wall is provided to partition the high temperature flow path, the temperature sensor is provided on one side of the partition wall, and the control device is provided on the other side of the partition wall.