JPS5818566B2 - heat recovery equipment - Google Patents

Description

[Detailed Description of the Invention] This invention provides two air passages (for example, an air supply passage and an exhaust passage).
A total heat exchange device interposed airtightly across the passageway, and a heat transfer device configured as a closed circulation circuit with two heat exchangers (e.g., an evaporator and a condenser) disposed upstream of each of these passages. It is configured as a heat recovery device and is used as a device that recovers heat from the return air RA of indoor air that is being used for cooling and heating and supplies the heat to the guest's outside air OA.

During cooling operation, return air RA is generated in the exhaust path of the total heat exchanger.
The cold air inside is recovered and supplied to the outside air OA in the air supply path, and during heating operation, in addition to the total heat exchange device, a heat transfer device is used in combination to convert the warm heat in the return air RA into heat. The heat is recovered by the evaporator of the transfer device and then by the section in the exhaust path of the total heat exchange device, and the respective recovered heat is first recovered by the condenser of the heat transfer device and then by the section in the supply air path of the total heat exchange device. This is a device designed to supply outside air to the OA.

Furthermore, the heat exchange element of the total heat exchange device is made of a hygroscopic and heat conductive material so that it can also absorb moisture in the return air.
It improves thermal efficiency by recovering and conducting heat with both sensible heat and latent heat, and the evaporator and condenser of the heat transfer device are designed to have an appropriate heat exchange rate, so that during heating operation, in the psychrometric diagram, The heat transfer device is operated so that the line connecting the pre-cooled return air RA' by the evaporator and the preheated outside air OA' by the condenser does not cross the saturation line, thereby preventing frost and dew from forming on the total heat exchange device. This device is characterized by the fact that it does not stick.

Conventional total heat exchange devices that can simultaneously exchange latent heat and sensible heat and achieve efficient heat recovery include rotary and stationary types. For example, a total heat exchange device 3 composed of a heat exchange element 4 made of a roll of asbestos paper cardboard impregnated with a moisture absorbent is partitioned vertically or horizontally by a partition wall 11 as shown in FIG. A structure rotatably interposed between the passage 1 and the exhaust passage 2 is often used.On the other hand, as a stationary device, as shown in FIG. and asbestos plain paper 4b made of the same material are laminated alternately, and the corrugated boards 4a are alternately stacked so that, for example, the odd-numbered layers are connected to the air supply path 1 and the even-numbered layers are connected to the exhaust path 2. A structure in which the rain air passage is divided into two routes and interposed between the rain air passages 1 and 2 is often used.

However, in the total heat exchanger 3, during the heating season in winter, heat is recovered from the return air RA from the room and discharged outside as exhaust EA, and on the other hand, the recovered heat is given to outside air OA and returned indoors as supply air SA. If the humidity of the return air RA is abnormally high when introducing the return air RA into
When the temperature is 20℃ and the humidity is 95%, the line connecting the two on the psychrometric diagram (the dotted line in Figure 4) is the saturation line of 100% relative humidity at point A (17℃) and point B (5℃). It will be crossed by.

In such a state, when the return air RA is being cooled by the total heat exchanger 3, the humidity drops below the dotted line in Figure 4 and reaches a humidity of 100 at point A.
%, goes outside the saturation line, crosses the saturation line again at point B, and is exhausted at point B, but since the humidity is over 100% between points A and B, return air RA The moisture inside condenses on the surface of the heat exchange element 4.

This dew condensation phenomenon causes elution of the moisture absorbent from the surface of the heat exchange element 4, resulting in a decrease in the moisture absorption performance of the heat exchange element 4.

Furthermore, as shown in FIG. 5, if the humidity of return air RA is abnormally high and the temperature of outside air OA is extremely low, for example, return air RA
A has a temperature of 20℃ and humidity 75%, and outside air OA has a temperature of -20℃
, in the case of 100% humidity, the line connecting the two in the psychrometric diagram in Figure 5 points the saturation line of 100% relative humidity at point C (1
3°C) and point D (-20°C).

Therefore, when the return air RA is cooled by the total heat exchanger 3, 0
Since the humidity is 100% at temperatures below .degree. C., frost formation occurs on the surface of the heat exchange element 4 between points C, which adds to the increase in air passage resistance, resulting in a decrease in performance.

In this way, when the temperature and humidity conditions of the return air RA from the room and the outside air OA cross the saturation line in the psychrometric diagram, dew condensation and frost formation occur, and the total heat exchange device 3 acts as a heat recovery device. There are drawbacks that make it unusable.

Therefore, in order to prevent the formation of frost and dew condensation, a preheater H was conventionally installed at a position upstream of the total heat exchanger 3 in the air supply path 1, as schematically shown in FIG. After preheating the outside air as shown by the solid line in Figures 4 and 5, the preheated outside air O
After A', the indoor return air R is passed through the total heat exchanger 3.
The preheated outside air OA' was further heated by the heat recovered from A and introduced into the room as supply air SA.

However, since this preheater H consumes other heating energy such as electricity or gas, it has the drawbacks of increasing running costs, making operation and operation troublesome, and further increasing device costs.

Focusing on this point, the present invention does not require any separate heating energy, can prevent frost and dew condensation with a simple structure under any temperature and humidity conditions, and has stable heat recovery over a long period of time. The present invention is intended to provide a heat recovery device that can perform heat transfer operation.

To explain the present invention in detail with reference to the drawings, FIGS. 6 and 7 show each side according to the first invention. First, FIG. 6 shows a heat recovery device using a rotary total heat exchanger. Yes (a perspective view is shown in Fig. 12), the air supply passage 1 and exhaust passage 2 are separated by a partition wall, and the air supply passage 1 and exhaust passage 2 are arranged vertically in parallel, and the rain air passages 1 and 2 are arranged in an airtight manner across the middle. It consists of a total heat exchange device 3 and a heat transfer device 5 which includes air-to-air type exchangers 18 and 19 and forms a closed circulation path for a heat transfer medium between the air exchangers 18 and 19.

First, to explain the total heat exchange device 3, an example of the structure of the total heat exchange device 3 is shown in FIG. The heat exchange element 4 includes a heat exchange element 4, a motor 7 that rotates the element 4 at a slow speed of about 10 revolutions per minute, and an operation controller 8 that controls the rotation of the motor 7. A disk-shaped ventilation body 6 is rotatably supported in a structural casing 4a, facing openings on both sides of the casing 4a, and a partition backing 10 is traversed through the central axis of the ventilation body 6. As shown in FIG. 6, the lower half of the vent 6 is inserted into the exhaust path 2, and the upper half is inserted into the air supply path 1.

This ventilation body 6 is connected to a motor 7 by a round belt 9 stretched around the circumference of the body as shown in FIG. The space between the exhaust passages 2 and 2 can be interposed in the exhaust path 2.

The ventilation body 6 is a sheet-like material such as asbestos paper having heat conductive and hygroscopic properties, and is formed into a honeycomb-like porous body having a large number of air passages communicating in the axial direction. The required ventilation body can be easily manufactured by winding corrugated asbestos paper impregnated with a moisture absorbent into a roll.

As shown in FIG. 6, a rotary total heat exchanger 3 having such a structure is installed airtightly between the air supply path 1 and the exhaust path 2.
The downstream side of the air supply path 1 passes through the heat exchanger 12 and air supply fan 13 of the heat pump type air conditioner, and the upstream side of the exhaust path 2 passes through the filter 15 into the room 14. On the other hand, the upstream side of the air supply path 1 is exposed to the outdoors through a filter 16, and the downstream side of the exhaust path 2 is exposed to the outdoors through an exhaust fan 17.

The operation of the motor 7 is controlled by an operation controller 8, which is a relay circuit using control devices such as timers and relays, and continuous operation can be completely stopped by manual adjustment. Alternatively, the intermittent operation can be switched at any time.

Next, the heat transfer device 5 will be explained in detail.

As mentioned above, the air heat exchangers 18 and 19 are arranged upstream of the total heat exchange device 3 in the air supply path 1 and the exhaust path 2, respectively, and are arranged between the heat transfer medium and the introduced outside air OA and the heat transfer medium. Heat is exchanged between the air return air RA and the return air RA from the room.

Furthermore, the heat exchanger 18 is arranged at a higher position than the heat exchanger 19, and the upper and lower ends of the side heat exchangers 18 and 19 are connected to each other by piping 21 to form a closed circulation circuit, and therein, as appropriate, A quantity of heat transfer medium is enclosed.

22 is a drain pan installed below the heat exchanger 19.

This heat transfer device 5 is a device used only when heating the inside of the room 14, and is also used as a radiator that can impart heat to the outside air OA introduced into the heat exchanger 18 in the air supply path 1.
The heat exchanger 19 in the exhaust passage 2 can act as a heat receiver capable of extracting heat from the return air RA.

That is, by circulating the heat transfer medium in the closed circulation circuit in the direction indicated by the solid line arrow in FIG. 6, the heat exchanger 19 exchanges heat with the return air RA immediately before entering the total heat exchange device 3. The heat transfer medium whose temperature has been raised is sent to the heat exchanger 18 via the piping 20, where it exchanges heat with the low-temperature outside air OA just before entering the total heat exchange device 3 and is cooled, while the outside air OA Raise the temperature.

By performing this heat transfer in a cyclical manner, the introduced outside air OA is preheated immediately before it flows into the total heat exchange device 3, and becomes preheated outside air OA'.

Examples of the heat transfer medium used in the heat transfer device 5 include a condensable gas refrigerant such as the fluorocarbon refrigerant 21, and a non-evaporable antifreeze liquid such as a calcium chloride solution. Since it is not possible to create a natural circulation flow, it is sufficient to force the circulation using the pressure feeder 23.On the other hand, when a condensable gas refrigerant such as the fluorocarbon refrigerant 12 or 22 is used, the air temperature is lower. By laying the air passage, for example, the air supply passage 1, at a higher level than the higher air passage, for example, the exhaust passage 2, and setting the heat exchanger 18 at a higher level than the heat exchanger 19, heat exchange can be performed. Vessel 1
9 acts as an evaporator and the heat exchanger 18 acts as a condenser, making it possible to form a circulation circuit adapted to the natural circulation of a condensable gas refrigerant accompanied by a change in gas-liquid phase, and requiring no power at all. It goes without saying that the heat transfer device 5 can be easily provided.

In addition, in the case of a device using antifreeze, the heat transfer circuit does not need to be of high pressure resistant structure, so it can be a simple mechanism, whereas in the case of a condensable gas refrigerant, no power is required. In addition to the advantages, since it uses latent heat, the temperature difference between the condensing temperature and the evaporation temperature is small, so the return air RA
This has the advantage of increasing the temperature difference between the air and the outside air OA, thus increasing the heat recovery efficiency.

Of course, the latter heat transfer device 5 is not limited to the natural circulation type shown in FIG. 6, but can also be applied to a forced circulation type using a pressure feeder 23. There are no restrictions on the relationship between the air supply path 1 and the exhaust path 2.
This has the advantage that the device arrangement configuration can be set arbitrarily.

Next, in the apparatus shown in FIG.
The operation of the device when 22 is enclosed and allowed to circulate naturally will be explained.

During heating operation in winter, the air conditioner is operated for heating, and the heat exchanger 12 (acting as a condenser) heats outside air.

The total heat exchange device 3 is rotated at a predetermined rotation speed.

High-temperature, high-humidity return air from inside the chamber 14 is filtered by a filter 15 and comes into contact with a heat exchanger 19.

The return air is cooled and dehumidified by heat exchange with the refrigerant R''22. in the heat exchanger 19, and becomes pre-cooled return air RA'.

Here, when the temperature of the refrigerant is lower than the dew point of the return air, the return air is dehumidified and the pre-cooled return air reaches the half heat exchange element 4 existing in the exhaust passage 2, where the return air is The moisture and heat are absorbed by the vent 6 of the heat exchange element 4 and then discharged to the outdoors.

On the other hand, the refrigerant R-22 in the heat exchanger 19 receives heat from the return air, evaporates, and flows into the heat exchanger 18.

The vent body 6 of the heat exchange element 4, which has received moisture and heat from the return air, rotates and moves into the air supply path 1.

The low-temperature, low-humidity outside air OA is filtered through the filter 16 and heated by exchanging heat with the gas refrigerant R-22 of the heat exchanger 18 to become preheated outside air OA'.

The preheated outside air OA' reaches half of the heat exchange elements 4 present in the air supply path 1, and is heated and humidified by the ventilation body 6.

Thereafter, the outside air is heated to a predetermined temperature in the heat exchanger 12 and then sent indoors.

On the other hand, the gas refrigerant in the heat exchanger 18 is condensed and becomes a liquid refrigerant, which flows down to the heat exchanger 19 disposed below due to its own weight.

Further, the ventilator 6 of the heat exchange element 4, which has been deprived of temperature and moisture by the outside air OA, rotates and moves into the exhaust path 2.

The same operation is repeated thereafter, and the heat and moisture in the return air are transferred to the outside air.

The conditions for precooling and preheating the return air and outside air will be described later.

Next, during cooling operation in summer, the air conditioner is operated for cooling, and the heat exchanger 12 (which acts as an evaporator)
to cool the outside air.

The total heat exchanger 3 is rotated at a predetermined rotation speed.

In this case, since the outside air has a higher temperature than the return air, a natural circulation flow of the refrigerant is not established in the heat transfer device 5, and therefore,
The heat transfer device 5 is inactive and no heat transfer by the refrigerant between the return air and the outside air takes place.

However, since the total heat exchange device 3 is rotating, the heat and moisture of the high temperature and high humidity outside air are transferred to the return air via the total heat exchange device 3.

That is, high temperature, high humidity outside air is cooled and dehumidified by relatively low temperature, low humidity return air, and is further cooled to a predetermined temperature in a heat exchanger before being sent into the chamber 14 .

At this time, under the temperature and humidity conditions of general air conditioning, the line connecting the points indicating the temperature and humidity of outside air OA and return air RA on the psychrometric diagram does not cross the saturation line of 100% relative humidity, so the total heat exchanger 3 No condensation will occur.

Therefore, the heat transfer device 5 may be in a rest state as described above.

In the intermediate period between summer and winter, there is no need to heat or cool the outside air, and only ventilation is required.

Therefore, in this case, there is no need to rotate the total heat exchange device 3.

However, when the total heat exchange device 3 is completely stopped,
Since there may be inconveniences such as dew condensation forming on the ventilator 6, the operation controller 8 should be switched and operated for, for example, 30 minutes to 1 hour.
It is desirable to operate the heat exchange element 4 intermittently, for example at a speed of 10 rpm or less, for several minutes every hour.

Such operation can prevent elution of the moisture absorbent and clogging of dust due to dew condensation in the heat exchange element 4.

Considering the winter heat recovery in the heat recovery operation described above further, for example, when only the total heat exchanger 3 is used in a severely cold region, the humidity of the return air RA- is abnormally high and the outside air OA If the temperature of the return air RA is extremely low, moisture in the return air RA that performs heat recovery will condense or frost on the total heat exchanger 3 for the reasons mentioned above, causing various problems.

However, in the apparatus of the present invention, since the total heat exchange device 3 and the heat transfer device 5 consisting of the heat exchangers 18 and 19 are combined as described above, the total heat exchange device 3 and the heat exchangers 18 and 19 are combined.
By appropriately designing the heat exchange capacity of , it is possible to prevent condensation and frost from occurring.

That is, the total heat exchange device 3 and the heat exchangers 18 and 19 convert the indoor return air RA into pre-cooled return air RA' which is pre-cooled by the heat exchanger 19.
A line connecting the points representing the temperature and humidity on the psychrometric chart of and preheated outside air OA′ obtained by preheating outside air OA with the heat exchanger 18
As explained below, it must be designed to be located within the saturation line as shown in FIG.

This makes it possible to prevent dew condensation and frost formation, which is a major feature of the present invention.

To explain this with reference to Figs. 6, 8, and 9, for example, when outside air OA is at -20°C and humidity is 100%, return air R
When the temperature of A is 20°C and the humidity is 75%, the preheated outside air (OA'
, temperature -6℃, humidity 35%) and pre-cooled return air (RA', temperature 13℃, humidity 90%) The line connecting each point on the psychrometric diagram crosses the saturation line of 100% relative humidity. Not yet.

That is, the evaporation temperature T of the heat exchanger 19 acting as an evaporator
By designing so that c is 0°C or higher,
The return air (RA 20°C) becomes pre-cooled return air (RA', 13°C) cooled to a temperature range higher than the evaporation temperature, and the heat acts as a condenser with a condensation temperature almost equal to the evaporation temperature. The exchanger 18 allows outside air (OA, -20°C
) is heated to become preheated outside air (OA', -6°C),
On the other hand, in the total heat exchanger 3, the precooled return air RA'
is further cooled and discharged as exhaust air (EA, -1°C), and the preheated outside air OA' is further heated and introduced into the room as supply air (SA, 8°C). .

In this way, the return air RA at 20°C becomes the exhaust air EA at -1°C, and this difference in calorific value is recovered by the device of the present invention.
Fresh outside air OA at a temperature of -20°C is heated by the heat recovered by the device to become supply air SA at 8°C and introduced into the room, and the efficiency of heat recovery and heat transfer is very high.

Furthermore, looking at the state of the air passing through the total heat exchanger 3 at this time, precooled return air RA' - supply air SA - exhaust air EA - preheated outside air O
The lines connecting the points that represent A' on the psychrometric diagram are as shown in Figure 8, and do not cross the saturation line.

Therefore, by combining the total heat exchange device 3 with the heat transfer device 5 consisting of heat exchangers 18 and 19 and appropriately designing the heat exchange capacity of the heat exchangers 18 and 19, the humidity of the return air RA can be reduced to an abnormally high level. , and the total heat exchange device 3 can be operated normally without dew or frost adhering to the heat exchange element 4 even under conditions where dew or frost is likely to form, such as when the outside air OA is at a low temperature. This is the result.

Furthermore, when compared with a case where the heat transfer device 5 combined with the total heat exchange device 3 is heated with another heat source such as a conventional air heater or a gas burner, the heat transfer device 5 is more efficient.

That is, the total heat recovery efficiency η of the total heat exchange device 3 and the heat transfer device 5 is where △11 is the amount of heat recovered by the heat transfer device 5 △12 is the amount of heat recovered by the total heat exchange device 3 △i4 is This is the difference in calorific value between the return air RA from inside the room and the outside air OA.

Therefore, in the psychrometric diagram in Figure 8, △11. △14 is expressed in terms of length, so calculating it is △11/△
14 = 0.2, and on the other hand, the heat recovery efficiency of the total heat exchanger is 7
When designed to be around 0%, -〇, 2 + 0.7 (1-2
X0.2)-0.62.

On the other hand, if we use a conventional device (external preheating method) that heats this Δ11 minute with another heat source such as an electric heater or gas burner, the heat recovery efficiency η' in this case is shown in the psychrometric diagram in Figure 4. As shown, 10,7 X(1-0,2) -0,56 When the temperature and humidity conditions are different from those shown in FIG. 8, the value becomes η-0,58, while η'-0,49.

In this way, when the relationship between the heat recovery efficiency of the conventional external preheating method and the heat recovery preheating method of the present invention is plotted by changing the temperature and humidity conditions and changing △+1/△i4, the result is as shown in Figure 9. Become.

As is clear from Fig. 9, η>η', and the device of the present invention is more efficient than the conventional device that heats outside air with another heat source such as an electric heater or gas burner. It also has the effect of saving energy.

EXPERIMENTAL EXAMPLE Next, an explanation will be given of experiments conducted using the apparatus of the present invention under the following various conditions to determine the presence or absence of dew condensation and frost.

In the table above, RH is humidity, and the value in parentheses is the depth dimension of the heat exchanger (other conditions).The front surface of the heat exchanger has an air velocity of 3 m/s, an air volume of 1200 m"/h, and a front area of 0.11 mj. Effective length: 510X 〃 Heat exchange tube diameter: 9.5 Heat exchanger fin pitch: 3 If the number of heat exchanger rows is designed as above, outside air O
Dew condensation in the total heat exchange device 3 for A condition,
It was found that frost formation can be prevented.

Note that when the heat exchanger 18.19 is not used for full heat under the return air RA conditions of 20°C and 75% humidity, if the outside air OA condition is 100% humidity, the outside air is 5°C or lower, for example 0°C or lower. Then, the line connecting the point of temperature 20°C and humidity 75% and the point of temperature 0°C and humidity 00% crosses the saturation line of relative humidity 100%, and condensation and frost occur in the total heat exchanger 3, causing operation to stop. It became impossible.

From the above explanation, it has become clear that the device of the present invention can efficiently recover heat without causing dew condensation or frost.
This will be explained with reference to FIG.

First, in FIG. 7, a stationary heat exchange element (see FIG. 2) is used as the total heat exchange device 3, and the side heat exchangers 18 and 19 in the heat transfer device 5 are replaced with integrated natural circulation heat exchangers. The heat exchanger has a heat exchange tube having fins on the outer peripheral surface, which is formed from a heat pipe made of an airtight hollow straight tube with both ends closed. The heat pipe is vertical, inclined, or horizontal and is disposed to cross between an air supply path 1 and an air exhaust path 2 arranged in parallel.

In the heat pipe, when the enclosed condensable gas refrigerant is heated by the high-temperature return air RA from the chamber 14 at the tube end located at the lower position, it evaporates and vaporizes and rises in the hollow part of the tube, and then rises at the upper position. A known heat transfer method that allows stable circulation within a series of straight pipes, with natural circulation accompanied by phase changes such as when heat is radiated to the low-temperature outside air OA at the end of the pipe, it condenses and liquefies, flows down the pipe, and reaches the end of the lower pipe. The pipes are preferably arranged vertically or with an inclined slope as shown in the figure, but if it is necessary to lay straight pipes horizontally depending on the arrangement of the air supply path 1 and the exhaust path 2, the heat By layering a wick structure in which a heat transfer tube is equipped with an inner wall layer made of a porous material with many communicating narrow passages on the inner wall of the pipe, the gas flow path and liquid flow path are clearly distinguished and smooth natural circulation is achieved. It is possible to maintain it.

On the other hand, the total heat exchange device 3 uses a known stationary type total heat exchange device 3 whose basic appearance is schematically shown in FIG. 2 and whose structure has been explained in the above explanation. It is suitable as a simple form that does not require .

The heat recovery device with this configuration has the advantage that it does not require any power, and furthermore, by arranging the heat transfer device 5 horizontally, it can be operated even in summer as well as in winter. This makes it possible to prevent excessive dew condensation on the heat exchange element 4.

Next, in the device shown in FIG. 10, in the heat transfer device 5 of natural circulation or forced circulation accompanied by a phase change, an on-off valve 24 is interposed in the circulation circuit, and the on-off valve 24 is closed when not in use. This has the advantage that the flow of the heat transfer medium can be completely stopped, unnecessary heat transfer operation can be regulated, and the thermal efficiency of the heat recovery device as a whole can be improved.

Furthermore, this device normally becomes a part of the partition wall 11, and when necessary, the part of the partition wall 11 that is in contact with the pre-cooled return air RA' and the supply air SA, which forms the boundary between the air supply path 1 and the exhaust path 2, is provided with pre-cooled return air. A bypass damper 25 is provided that allows a part of RA' to flow directly by bypass to the air supply path 2 side downstream of the total heat exchange device 3.

By attaching the bypass damper 25,
As at the beginning of the heating operation, the room was not sufficiently warmed and the temperature of the return air RA did not reach a sufficiently high temperature, so heat exchanger 1
When the temperature of the medium in 8 is not high enough,
That is, in an abnormal case where low-temperature outside air OA is insufficient as a preheating source, the flow rate of the return air RA to be heat exchanged in the heat exchanger 19 is increased to increase the temperature, and some of the precooled return air is By configuring the base, ' to directly merge with the supply air SA and return it to the indoor side, it is possible to increase the heat transfer efficiency without substantially increasing the exhaust volume, and to prevent such abnormal operation. It has the advantage of being able to carry out heat recovery operation without causing dew or frost even in the case of severe conditions.

As described above, the device of the present invention successfully combines a total heat exchange device that utilizes not only sensible heat but also latent heat, and a heat transfer device consisting of two heat exchangers in a closed circuit, and furthermore, the heat exchange capacity of these devices is effectively combined. This device was designed with reference to the psychrometric chart, and was designed to recover heat from indoor ventilation and give this heat to fresh air outside.This allows ventilation of air-conditioned rooms to be done by cleverly utilizing exhaust heat. be exposed.

In particular, due to the effects of the two heat exchangers mentioned above, the system can be used efficiently without condensation or frost even during the cold winter months, and the range of use in low temperature ranges has been expanded.

Moreover, since effective heat recovery can be performed in a relatively low temperature range, there is no need to separately install a preheater such as an electric heater, making it economical, offering high safety, fewer failures, and providing an inexpensive device. .

Furthermore, even though the preheating method is adopted, the heat recovery efficiency is improved as mentioned above, and during heat recovery operation where there is no risk of frost or dew condensation, the preheating circuit can be operated without any special operation. It also has the effect of being able to stop and only continue the total heat exchange operation, making the present invention a truly practical heat recovery device.

[Brief explanation of drawings]

Figure 1 is a partially cutaway external perspective view of an example of a rotary total heat exchanger, Figure 2 is a perspective view schematically showing the main parts of an example of a stationary total heat exchanger, and Figure 3 is a conventional heat recovery system. 4 and 5 are temperature-humidity relationship diagrams for the device shown in FIG. 3, and FIGS. 6 and 7 are schematic mechanical diagrams for each side of the device of the present invention. , FIG. 8 is a temperature-humidity relationship diagram for explaining the characteristics of the device of the present invention, FIG. 9 is a relationship diagram of heat recovery efficiency with respect to preheating ratio, and FIG. 10 is an example of the device of the present invention. FIG. 2 is a schematic diagram of the mechanism. 1...Air supply path, 2...Exhaust path, 3...
... Total heat exchange device, 4 ... Heat exchange element, 5
... Heat transfer device, 6 ... Ventilation body, 18
．． 19...Heat exchanger, 23...Pumping machine, 24...Opening/closing valve.

Claims (1)

[Claims] 1. A heat exchanger formed by forming the total heat exchange device 3 into a honeycomb-shaped ventilation body 6 having multiple layers of a large number of parallel communicating air passages with both ends open and made of a sheet-like material having hygroscopic and heat conductive properties. The total heat exchange device 3 is interposed between the solid air passages 1 and 2 by airtightly crossing the air supply passage 1 and the exhaust passage 2' (! The heat exchange element 4 cooled by the return air RA cools the outside air OA and supplies air SA to the room.
On the other hand, an air-to-air form exchanger 1 is installed in the air supply path 1 and the exhaust path 2 at a position upstream of the total heat exchange device 3.
8 and 19 respectively, and
are connected to form a closed circulation circuit for the heat transfer medium, and the heat in the return air RA during heating operation is transferred to the heat exchanger 19 of the closed circulation circuit.
After being recovered and pre-cooled by the total heat exchanger 3, the return air RA is further recovered and cooled.
After being preheated in step 8, the air is further heated by the total heat exchanger 3 and then supplied into the room as air SA, and in the psychrometric diagram, the temperature and humidity points of the pre-cooled return air RA', which is the pre-cooled return air RA, and the outside air OA are preheated. A heat recovery device that is operated such that a line connecting preheated outside air OA' and a point of temperature and humidity is located within a saturation line. 2. The heat recovery device according to claim 1, wherein the heat transfer medium is a non-evaporable liquid, and a pressure feeder 23 for forcibly circulating the non-evaporable liquid is interposed in the closed circulation circuit. 3. The heat recovery device according to claim 1, wherein the heat transfer medium is a condensable gas refrigerant capable of transferring heat through phase change. 4. The air-to-air type exchangers 18 and 19 have their heat exchange tubes formed of beat pipes, and the heat exchange tubes are integral heat exchangers that also serve as a closed circulation path. The heat recovery device according to item 3. 5. The air type exchangers 18 and 19 have a level difference such that the side in contact with the high-temperature side air is at a lower position than the other, and the closed circulation circuit is configured to allow natural circulation of the condensable gas refrigerant. 4. A heat recovery device according to claim 3, which is an adapted circuit. 6. The heat recovery device according to claim 3, wherein the closed circulation circuit is a circuit for forcedly circulating a condensable gas refrigerant. 7. The heat recovery device according to claim 5 or 6, wherein the closed circulation circuit has an on-off valve 24 and can circulate the condensable gas refrigerant only when necessary. 8. The total heat exchange device 3 is constituted by a heat exchange element 4 formed into a honeycomb-shaped ventilation body 6 having multiple layers of a large number of parallel communicating air passages with open ends at both ends made of a sheet-like material having hygroscopic and heat conductive properties. , the total heat exchange device 3 is interposed between the air supply passage 1 and the exhaust passage 2 so as to intersect the air supply passage 1 and the exhaust passage 2 in an airtight manner,
During cooling operation, the outside air OA is cooled by the heat exchange element 4 cooled by the return air RA of the indoor air and supplied into the room as air SA, while the Air-to-air heat exchangers 18 and 19 are respectively arranged at positions on the upstream side, and the heat exchangers 18 and 19 are connected to form a closed circulation circuit for the heat transfer medium. The heat in the air RA is recovered and precooled by the heat exchanger 19 of the closed circulation circuit, and then further recovered by the total heat exchanger 3 to cool the return air RA, while the conductor outside air OA is preheated by the heat exchanger 18. After that, the total heat exchanger 3 heats the air and supplies it into the room.In the psychrometric diagram, the temperature and humidity points of the pre-cooled return air RA', which is the pre-cooled return air RA, and the pre-heated outside air OA, which is the pre-heated outside air OA, are shown in the psychrometric diagram. ' The line connecting the temperature and humidity points is located within the saturation line. A heat recovery device characterized in that a part of the pre-cooled return air can be directly bypassed into the supply air downstream of the total heat exchange device 3.