JP2009008382A - Decompression boiling/cooling-heat collecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To radiate heat by low energy from a computer and a dwelling space, by developing a mechanism for radiating the heat from a cooling part by absorbing the heat from a heat source with a simple structure. <P>SOLUTION: This decompression boiling/cooling-heat collecting device has a vacuum vessel having a heat collecting part and the cooling part by sealing a working fluid in the vacuum vessel in a two-phase state of a liquid phase and a gaseous phase with the vacuum vessel, and is characterized in that the cooling part is set above the heat collecting part in a gravity field. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an apparatus that performs efficient heat transport.

A technology for taking out heat from solar heat or low-temperature wastewater and using it effectively is used as a solar collector or heat pipe.
The inventor previously proposed a high-efficiency low-temperature heat collection panel and its heat transport system (see FIG. 8) as Patent Document 1 (Japanese Patent No. 3886045). This proposal is aimed at utilizing solar heat, and its configuration includes a solar heat collecting part, a pressure reducer, a header, and a condenser, and forms a heat medium circulation path that connects each device to circulate the heat medium. In the low-temperature heat collecting and transporting system, the heat medium circulation path is connected to the condenser via the header and the upper part of the heat collecting part installed at an inclination, and is connected to the condenser and the lower part of the heat collecting part. And a branch path that is branched from the header and connected to the condenser and the lower part of the heat collecting part.The header is formed from a gas-liquid mixture caused by bumping generated in the heat collecting part. A baffle plate that separates the liquid and flows the liquid to the branch path is provided, the heat medium circulation path is depressurized to use a gas medium-liquid heat medium, and the circulation path is provided. It is intended to be a heat and heat transport system, to obtain drinking water, etc. There is provided a system for use in.

  In addition, in Patent Document 2 (Japanese Patent Laid-Open No. 10-300242), a part of an inner glass tube 2 in which a liquid working medium is sealed is inserted into an outer glass tube 1 whose interior is held under reduced pressure. In addition, the working medium is vaporized at the insertion portion in the outer glass tube in the inner glass tube 2 and the working medium vaporized in the exposed portion outside the outer glass tube in the inner glass tube is liquefied, so that the latent heat accompanying liquefaction is reduced. A hot water device (see FIG. 9, which uses water described in Patent Document 2) is disclosed that uses water to warm water to make warm water. In this type of solar heat utilization device, the heat collecting part transmits sunlight and is covered with a transparent glass tube on the outside in order to block it from the outside air, and the outside glass tube is also evacuated to improve heat insulation performance. The

Japanese Patent No. 3886045 Japanese Patent Laid-Open No. 10-300242

  The present invention eliminates the need to cover the heat collecting part with a vacuum glass tube and develops a mechanism that absorbs heat from the heat source and dissipates it from the cooling part with a simple structure as a whole, and releases it from the computer and living space with low energy. The purpose is to do.

  The present invention encloses a working fluid in a liquid phase and a gas phase in a vacuum vessel, absorbs external heat from the liquid phase part, and is cooled in the gas phase part to change the phase from gas to liquid. Sometimes it uses the release of latent heat to the outside. The working fluid sealed under reduced pressure is always in a saturated state and utilizes a phenomenon in which it can easily boil and efficiently carry heat to the cooling section if the temperature is higher than that of the cooling section. It is sufficient if there is a temperature difference between the cooling part and the heat collecting part, and it is not necessary to cover the heat collecting part with a vacuum glass tube.

The main configuration of the present invention is as follows.
1. A working fluid is sealed in a vacuum vessel and a vacuum vessel in a liquid phase and a gas phase, and the vacuum vessel is a vacuum boiling cooling / collecting device having a heat collecting part and a cooling part. A reduced-pressure boiling cooling / collecting device, wherein the cooling unit is set above the heat collecting unit.
The heat collecting part does not need to be covered with an outer cylinder on the outer periphery of the vacuum vessel and is exposed to a heat source.
2.1. The vacuum boiling cooling / collecting device described in 1 is provided with a radiator for radiating heat from the inside to the outside, wherein the heat collecting part is disposed adjacent to the heat generating part, and the cooling part is disposed on the outer surface of the device. Equipment.
3.1. The vacuum boiling cooling / collecting device described in 1 is arranged on the roof surface, the cooling part is in contact with the snow stopper, and the heat collecting part is arranged on the lower slope continuous with the cooling part. A snow melting device for roofs, which is a snow melting device.
4.1. A mobile vehicle equipped with the vacuum boiling cooling / collecting device described in 1.
An air conditioner for a moving vehicle, wherein the heat collecting part is arranged on a floor, a wall or the like on the inner surface of the vehicle, and the cooling part is arranged on a ceiling, a rear part or the like of the vehicle.
The moving vehicle can be applied to automobiles, passenger cars, cargo sections, trains, etc., and both air cooling and water cooling can be used as a cooling heat absorption device, and condensate of air conditioning and drainage of hydrogen automobiles can be used as water sources.
5.1. A building air conditioner comprising the reduced-pressure boiling cooling and heat collecting apparatus described in 1., wherein the heat collecting part is disposed indoors and the cooling part is disposed outdoors.
The building can be applied to a residence, a building, a factory, a warehouse, a commercial facility, a barn, a horticultural facility, an indoor sports facility, an arbor, etc. It can also be applied to building materials and fittings such as roofing materials and wall materials.

6). A vacuum vessel and a vacuum vessel enclose a working fluid in a liquid phase and a gas phase in a two-phase state, and the vacuum vessel is a vacuum boiling cooling / collecting device having a heat collecting part on the lower side and a cooling part on the upper side, The cooling unit is capable of exchanging heat with the refrigerant, and the heat collecting unit is capable of exchanging heat with the heat medium.

In the present invention, waste heat or heat can be supplied by a simple mechanism, and energy required for that purpose is zero or almost no, and energy is saved.
Space can be saved because it can be brought into direct contact with the heat source to be waste heat and the shape is also free.
Basically, the endothermic side can be used in a state higher than the temperature to which the cooling side is exposed. Therefore, when exposed to the atmosphere (room temperature), it can be used normally if the temperature is higher than the outside air. If the cooling unit is brought into contact with water droplets, etc., the cooling unit can be cooled to a temperature lower than the outside air, and the heat collecting unit can be cooler than the ambient temperature (room temperature) or the amount of heat to be transferred can be increased. It is. A working fluid is sealed in a vacuum (reduced pressure) state in a two-phase state of a liquid phase and a gas phase in the vacuum vessel, and the vacuum vessel is a portion where the working fluid exists in the liquid phase and the working fluid is in the air. A cooling part that exists as a phase, and the working fluid absorbs heat energy from the outside of the container or dissipates heat to the outside of the container, so that it can be reversibly changed into a liquid phase and a gas phase. It is a heat collector.
It can be applied to air conditioning, computer cooling, vehicle air conditioning, snow-melting roofs, building materials such as roofs and walls, air conditioning partitions, etc., and can save energy.
As a result of the demonstration test of the indoor temperature control using the vacuum boiling panel, it was confirmed that the indoor temperature could be higher than the outside air temperature. Combined with a vacuum boiling solar panel, the heat obtained by the solar panel can be stored in a heat storage tank and used as a heat source for the vacuum boiling panel installed indoors, using the vacuum boiling cooling and heat collecting structure of the present invention. Thus, indoor temperature control using solar heat becomes possible.

  The working fluid is sealed in a two-phase state of liquid and gas in a vacuumed case, and the heat of the heat collecting part is efficiently transported to the cooling part by cooling the cooling part (the working fluid is water or ethanol aqueous solution) etc). With such a simple combination, it is possible to use heat with minimum power in various applications such as air conditioning, heat collection, cooling, and snow melting. It is similar to a heat pipe but uses the vacuum boiling phenomenon rather than the wick capillary phenomenon. The heat collecting part and the cooling part are in the shape of a plate or a tube. In the gravitational field, the cooling part needs to be above the heat collecting part. The heat collecting part does not need to be horizontal, and the heat collecting part and the cooling part do not need to be connected vertically. There are various methods for collecting heat at the heat collecting section or cooling the cooling section, such as air cooling, water transpiration, and water cooled by a heat pump.

Each component will be described.
1. Working fluid Water, alcohol, alcohol / water mixture, etc. are safe and easy to handle. Water is an efficient medium because it absorbs energy of 2 to 2.5 kw by vaporizing 1 g and collecting heat. Alcohol has a low freezing point and can be used in cold environments. The working fluid is not limited to these three types and can be used theoretically as long as it causes a phase change between liquid and gas.

2. Vacuum container A vacuum container depressurizes a sealed space and encloses a working fluid. Since the pressure is reduced close to a vacuum, it is necessary to provide a structure such as a support wall inside the container so that it does not deform at atmospheric pressure. It can be made of metal, synthetic resin or the like. For metal, it is necessary to ensure hermeticity with a solvent, and when it is made flat, it is necessary to provide a large number of intermediate support members as a measure against atmospheric pressure, and processing accuracy is required. Since the synthetic resin can be molded as a whole by a forming die, it can be manufactured integrally and simultaneously, including hermeticity and an intermediate support. On the other hand, there are restrictions on mold technology.
A vacuum vessel contacts a heat part and a cooling part turns into a cooling part. Since the cooling unit is a place where a working fluid such as water exists as a gas, the cooling unit needs to be positioned above the heat collecting unit that exists as a liquid. The heat collecting part and the cooling part may be bent or linear.

3. Heat collecting part The heat collecting part is a part in which a working fluid such as water exists as a liquid phase and directly contacts the high temperature part or absorbs heat energy from sunlight and vaporizes in a bumpy manner. The gas vaporized by bumping moves to an upper cooling unit. The heat collecting part can be designed according to the size and shape of the object to be collected.

4). Cooling unit In the cooling unit, a working fluid such as water is present as a gas phase, and is cooled and discharged from the gas when condensed to release latent heat to be changed into a liquid. The liquid moves to the heat collecting section below. The liquid passes through the system or a separately provided pipe and moves to the heat collecting section. This cooling occurs when the cooling part is in a lower temperature atmosphere than the heat collecting part. It is also possible to forcibly create a low-temperature region by making a mist-like atmosphere in which water flows. It is efficient if the cooling part has a wide area such as a fin shape so that it is easy to cool.
The heat collecting section and the cooling section are directly connected so that the working fluid can move.

5). Structure When the structure is shown in a stylized manner, it can be a very simple structure. For example, as shown in FIG. 1, a heat collecting apparatus 1 that uses a vacuum boiling phenomenon is configured from a horizontal heat collecting section 2 and a cooling section 3 that is bent and rises into an L shape. In the example shown in the drawing, the flow surface of the working fluid 4 is at a position higher than the horizontal of the heat collecting unit 2 at the L-shaped rising portion, and the bumped gas surely moves to the cooling unit.

  The application can be used mainly for applications used for cooling purposes. It can also be used for applications that use the cooled heat, for example, air conditioning, computer cooling, various equipment cooling, vehicle air conditioning, snow melting roofs, building materials such as roofs and walls, air conditioning partitions, etc. It is. The building can be applied to a residence, a building, a factory, a warehouse, a commercial facility, a barn, a horticultural facility, an indoor sports facility, an arbor, etc.

<Function test>
An experiment was conducted to confirm the energy efficiency of the vacuum boiling cooling and heat collecting mechanism of the present invention. An outline of the apparatus is shown in FIG. It is a simple outdoor device that absorbs solar heat by connecting a condenser C to a solar heat collector B that is evacuated and half-filled with water, and circulating water cooled by a cooling tower E.
In the natural environment, the increase in outside air temperature is mainly caused by solar heat, and plants control the temperature by transpiration of water mainly from the leaves. This device was created with reference to this natural temperature control mechanism. The heat absorbed by the solar heat collector was discarded to the atmosphere by evaporating water from the cooling tower instead of leaves.
The heat collector is made of transparent glass and directly exposed to air, and is not a double tube structure. Because it is transparent, the liquid level can be observed directly. The vacuum pump is used when changing the experimental conditions such as changing the amount of liquid to be injected, and is not necessary in the actual machine.
In this test apparatus, the condenser C corresponds to the cooling unit, and the condenser C is configured such that the piping of the cooling unit is passed through the cooling water. This cooling water circulates in the cooling tower E, and the latent heat released at the time of condensation is carried by the circulating cooling water, evaporated in the cooling tower E, and allowed to cool. The environmental temperature evaporating in this cooling tower and the amount of evaporation are measured to measure the effect of heat collection and cooling.
In this apparatus, the condensed liquid returns to the header A via the return path. This apparatus was created as an experimental system, and it is not always necessary to separate the return path in an actual machine.

  The measured results are shown in Table 1. As shown in Table 1, the transpiration temperature of water in the cooling tower is always lower than the outside air temperature, and it is understood that the heat obtained from the sun can be thrown away into the outside air at a low temperature. In general, heat is assumed to move from a high temperature to a low temperature, and the exhaust heat during cooling is discarded at a high temperature, contributing to a heat island. However, here it is possible to learn from the natural mechanism and exhaust it to the surrounding environment as low-temperature heat.

  This phenomenon is caused by the fact that the water in the collector is evacuated and is at a low pressure, and is always in a saturated state just before boiling, and if the collector has a slight heat input such as solar heat, or more than the cooling water. If the water in the heater is slightly hot, it takes advantage of the phenomenon that water immediately takes away heat and the water boils vigorously. This is boiling under reduced pressure, resulting in a fairly intense water movement. The water in the heat collector, along with the evaporated water vapor, circulates vigorously in the closed system of the cooler that is the heat collector and the condenser. And the heat given to the heat collector is efficiently conveyed to the cooler.

Experimental measurement was continued using the test apparatus shown in FIG. FIG. 3 shows the amount of transpiration heat obtained by multiplying the amount of transpiration of water from the cooling tower by the latent heat of evaporation for various solar heat inputs (amount of solar radiation, horizontal axis). Although it is not exact because of the influence of heat transfer other than transpiration and the time lag of temperature rise, about 90% of the solar radiation is exhausted by transpiration. When the relationship between the amount of solar radiation and the amount of heat of transpiration is obtained from this test data, it can be expressed by the following equation.

y = 0.8753x−0.004

  As shown in Table 1, this exhaust heat is performed at a temperature lower than the outside air temperature. That is, the temperature of the water coming out from the water put in the cooling tower is lower, and the heat collector is cooled again by flowing this water into the condenser. For example, even if 1.5 kW of solar heat hits the collector, the entire system is always kept at ambient temperature and not hot. It should be noted that the amount of water that evaporates in the cooling tower is such that plants are stored in the roots in nature, and is estimated to be about one-hundredth of rainfall. This type of collector is called a cool solar panel, providing a space to relieve the heat from the sun in the summer, or by cooling the cooling tower and circulating the heat medium heated by solar heat as it is in winter It can contribute to significant energy savings by providing a space to relieve the pressure and using it as an auxiliary system for outdoor units such as air conditioners and heat pump water heaters although detailed explanations are omitted.

<Vacuum boiling cooling / heat collecting device>
The present embodiment shows a basic form of the vacuum boiling cooling / collecting apparatus 1. A vacuum vessel having a horizontal portion as the heat collecting portion 2 and an L-shaped cooling portion 3 is provided, and water or the like is filled from the heat collecting portion to the L-shaped portion to obtain a working fluid. The cooling unit is in a reduced pressure state in a vacuum, and the working fluid is saturated in a gas phase state.

  The heat collecting unit 2 is disposed so as to contact the high heat unit, and the working fluid is vaporized in a boiling state and sent to the cooling unit 3. The cooling unit 3 is configured to release latent heat when cooled and returned to the liquid. Since it returns to a liquid phase by standing to cool, the cooling part is kept in a reduced pressure state, and when it receives heat from the heat collecting part, it can be easily vaporized into a boiling state.

<Example of water-cooled computer case>
In this embodiment, computer equipment is loaded in a plurality of stages on a large computer or the like, and a vacuum boiling cooling having the same basic configuration as the apparatus shown in the first embodiment is provided below the computer loading shelf where heat is trapped inside the housing. -An example in which a heat collecting device is provided. The heat collecting parts 22a and 22b are provided horizontally, and cooling parts 23a and 23b which are bent and started up in an L shape are provided. In this example of the apparatus, the cooling parts 23a and 23b are provided with slits and fins (it is better to increase the number in the vertical direction), drop water drops to enhance the cooling effect, and configure the water-cooled computer case 21. Yes. When the cooling is sufficient, it is not always necessary to drop the water droplets, and it is possible to use air cooling. When the amount of heat released is large, it can be cooled by circulating low-temperature water or the like with a heat pump.

  In this embodiment, since natural convection in the case is used assuming a small amount of heat radiation, a fan is not necessary, and power associated with cooling is unnecessary, thus saving energy. The water placed under reduced pressure is always in a saturated state, and when it is hotter than the cooling part, it always boils and efficiently carries heat to the cooling part, so that heat can be prevented from getting into the case. It is also possible to cool the ceiling part in multiple layers. The entire computer case can be kept at a uniform temperature.

<Example of solar snow melting device>
This embodiment is an example in which the reduced-pressure boiling cooling / collecting device shown in the first embodiment is provided on an inclined roof, and the radiated heat is used as heat for melting snow (see FIG. 5).
A reduced-pressure boiling cooling / heat collecting device solar snow melting device 31 using solar heat is configured, which includes cooling portions 33a, 33b bent in an L shape from the heat collecting portions 32a, 32b. In this embodiment, since it is installed in a cold region, a working fluid such as alcohol having a low freezing point is used. When snow can fall freely from the roof, there is a risk of accidents due to falling, so a non-slip projection that temporarily stops the snow is formed on the roof, so the cooling section bent in an L shape is used for this snow stop can do.

  The snow is melted by the solar heat of the heat collecting part. Depending on the temperature, thermal efficiency can be expected to be over 100%. Prevent snow from accumulating on the heat collecting surface, for example, by sliding the snow in the heat collecting section. The water under reduced pressure is always in a saturated state, and when it is higher than the temperature of the snow, it always boils and efficiently carries the heat to the snow, and can efficiently melt the snow with solar heat. The heat transfer surface can be enlarged by inserting fins vertically into the snow. It is also possible to melt snow in multiple layers.

<Examples applied to mobile vehicles>
This embodiment is an example (see FIG. 6) provided in a moving vehicle in which the room temperature is likely to rise. As the vehicle, the present invention can be applied to automobiles such as passenger cars, buses, and freight cars, or train cars.
The heat collecting part 42 is provided on the indoor floor surface, and the cooling part 43 is provided outside the vehicle such as the rear part. The moving vehicle can sufficiently cool the cooling unit while moving, and can cope with it sufficiently. In the case of a moving vehicle, the heat from the engine and the solar heat input from the roof are also large heat sources. Therefore, the rise in the room temperature can be suppressed by installing the vacuum heat insulation panel 45 on the roof side to insulate. Further, the energy saving effect can be enhanced by installing the porous body 44 on the roof and flowing water droplets in combination with a means for cooling the roof surface by heat of vaporization. If a fuel cell or a hydrogen engine can be put into practical use, it is possible to further enhance the cooling effect by supplying discharged water to the cooling unit 43 or to the porous body 44 on the roof surface.
This structure can also be applied to vehicles such as trains. When the current air conditioning is used in combination, it is possible to use the moisture condensed by the air conditioning and the cold heat of the refrigerant for cooling the cooling unit, and the load of the air conditioning can be reduced. As the working fluid, antifreeze or alcohol can be used to avoid solidification in winter.
The water placed under reduced pressure is always in a saturated state. If the temperature is higher than that of the cooling part, the water is always boiled and efficiently transports heat to the cooling part. The entire room can be kept at a uniform temperature. For example, the cooling unit is provided with a slit for air cooling. A greater effect can be obtained by providing a water supply device using a capillary phenomenon or the like and cooling with the latent heat of vaporization of water.

<Example of partition>
This embodiment is an example (see FIG. 7) in which a reduced-pressure boiling cooling / collecting device is applied to an air conditioning panel 51.
In this example, a large number of vacuum vessels 54a to 54z are provided in the vertical direction, and the working fluid is sealed inside. A vacuum boiling cooling / heat collecting device 55 having a cooling unit 53 on the upper side and a heat collecting unit 52 on the lower side is configured. Each of the heat collecting unit 52 and the cooling unit 53 is provided with a structure that is connected to a hot water source and a cold water source from the outside of the panel and is in contact with a heat medium or a refrigerant.

  When a cold fluid flows in the upper part or a warm fluid flows in the lower part, the working fluid in the panel boils and reaches a temperature close to that of the cold (hot) hot fluid almost flowing on the entire surface. When used for a partition, the amount of cold (warm) hot fluid does not increase so much and the flow resistance is small, and the whole can be warmed or cooled. It can be used as a panel for heating and cooling simply by connecting it to a cold (hot) thermal fluid piping. Although this example showed the example of the partition which can move, it can be applied to a wall or a joinery, a blower fan etc. are unnecessary, and provides local air-conditioning equipment, such as personal air-conditioning of calm and energy saving be able to.

  In this embodiment, the partition shown in the fifth embodiment is arranged indoors. Since the vacuum boiling panel wraps water in the panel and depressurizes it, the water inside the panel boils just by applying heat to the bottom of the panel, and the whole panel can be warmed by releasing heat to the panel surface. It is possible. By providing solar heat to the lower part of the panel, it can be used in indoor spaces as a radiant heating system using natural energy.

A schematic diagram of the experimental apparatus is shown in FIG. The experimental apparatus is composed of a vacuum boiling radiation panel A, heat exchangers G and B, a constant temperature bath C, a vacuum pump D, piping connecting them, and the like.
In FIG. 10, the water pushed out by the pump attached to the thermostat C passes through the inner pipe of the heat exchanger G and transfers heat to the water that is the working fluid filling the inner side of the outer pipe and the lower part of the panel. Return to the thermostat C again. Since the system is depressurized, when heat is transferred from the hot water to the water, the water boils and becomes water vapor and moves to the top of the panel. Since the panel surface exposed to the indoor space is cooler than the steam, latent heat is released from the steam to the panel. The steam condenses into water and falls to the bottom of the panel. In order to prevent the temperature inside the test chamber from being affected, a heat insulating material was wound around the hose connecting the thermostat C and the heat exchanger G, and the thermostat was placed outside the room.
Eight thermocouples 61 to 68 were used to measure the temperature of each part. The thermocouple was connected to the data logger H, and using this, data was captured and recorded on a personal computer. Table 2 shows the details of the measurement locations for the temperature of each part.

Table 3 shows the specifications of the test room and equipment used in the experiment.
(1) The vacuum boiling radiation panel consists of a lower header tube filled with water and four thin tubes connected to it.
(2) The constant temperature bath is used for flowing warm water at a constant temperature to heat the water sealed in the panel.
(3) Measuring device The glove temperature is a temperature measured using a glove thermometer that is a virtual blackbody sphere, and in this example, the glove temperature was measured by putting a thermocouple in the glove thermometer. The glove temperature was measured to observe the effects of thermal radiation from the surroundings. Moreover, the electric power consumed by a thermostat was measured with the wattmeter.
(4) Installation location of the test room The installation location of the equipment is in the test room on the library rooftop (36 ° 33'07 ″ north latitude, 139 ° 39′28 ″ east longitude) of the Yagami campus of Keio University in Yokohama. is there.

The experiment was performed according to the following procedure.
(1) Open a valve installed in the middle of the hose connecting the upper and lower heat exchangers and enclose water. The amount of water was adjusted so that the water surface was “lower header tube” and “25 cm from the bottom of the panel” for each experiment. The system is sealed after water is sealed.
(2) Set the temperature in the thermostatic chamber from 25 to 50 ° C in increments of 5 ° C for each experiment, and circulate hot water.
(3) Evacuate using a vacuum pump. When the water temperature reaches the saturation pressure, evacuation is stopped.
(4) When the temperature and pressure are stabilized, the temperature of each part is recorded at 5-second intervals using a data logger.
(5) Record the hot water flow rate.

  The experiment was carried out 19 times in total from November 12, 2007 to January 18, 2008. Table 4 shows the conditions on each experimental day. In Experiment 9, the experiment was started at a hot water temperature of 25 ° C., and the hot water temperature was set at 30 ° C. at 13:00, 35 ° C. at 14:00, 40 ° C. at 15:00, 45 ° C. at 16:00, and 50 ° C. at 16:30. In Experiment 10, the experiment was started at a hot water temperature of 25 ° C., the hot water temperature was increased by 30 ° C. at 12:00, and thereafter the hot water temperature was increased by 5 ° C. every other hour.

The change of the average temperature for every part of each part of the vacuum boiling radiation panel in Experimental Examples 10 to 19 is shown in FIGS.
For comparison, FIG. 21 shows the temperature change of each part when hot water of 40 ° C. is flown without filling and depressurizing water up to a position 25 cm from the lower end of the panel.

  Radiation panels for indoor environment control are required to have a stable panel temperature and set the panel temperature to the user's preferred temperature. The factors that determine the radiation panel temperature using vacuum boiling and the effect of the panel temperature on the indoor environment are shown below.

Comparing FIG. 21 of the experiment using the panel without decompression and FIGS. 11 to 20 of the experiment using the decompressed panel, it can be seen that the temperature in the panel is raised by decompressing the panel. Looking at the temperature distribution of the panel, it can be seen that heat can be transported by boiling under reduced pressure because the temperature is raised not only to the bottom of the panel but also to the top of the panel. 12, 13, and 14 that have the same conditions other than the amount of water in the panel, the panel lower temperature becomes higher when the amount of water in the panel is large as shown in FIGS. 12 and 13. Thus, when the amount of water in the panel was small, the temperature in the middle and upper part of the panel was higher.
The reason why the temperature at the bottom of the panel increased when the amount of water in the panel was large was not because the temperature at the bottom of the panel increased due to the latent heat generated when the steam condensed, but the water level inside the panel was higher than the measurement position of the panel bottom temperature. This is because the temperature at the bottom of the panel represents the water temperature in the panel receiving heat directly from the hot water.

When the amount of water in the panel is small, the temperature in the middle and upper part of the panel is high, and the temperature does not decrease over time. This is because if the water temperature in the panel is the same, the amount of heat that the water in the panel obtains is the same, the amount of heat that the water per unit amount obtains increases, and the water pressure received from the upper water also decreases, so boiling is likely to occur. This is because steam and bumpy liquid easily move upward.
Looking at the change in the panel temperature over time, a stable panel temperature was obtained even after a lapse of time on most experiment days. However, as shown in FIGS. 12, 17, and 18, the experiments 11, 16, and 17 were performed. The panel temperature was unstable.
When considering the amount of water in the panel, both when the water surface is up to the lower header tube and when it is 25 cm from the bottom of the panel, both when the panel temperature is stable and when it is not stable Therefore, there is no relationship between the stability of the panel temperature and the amount of water in the panel.
The factor that the panel temperature is not stable is the initial water temperature of the water in the panel. Comparing FIG. 12 and FIG. 13 under the same experimental conditions, the panel lower part temperature immediately after the start of the experiment was about 30 ° C. in FIG. 12 and about 31 ° C. in FIG. Similarly, when FIG. 17, FIG. 18 and FIG. 20 with the same experimental conditions are compared, the panel header pipe temperature considered to be almost equal to the water temperature in the panel immediately after the start of the experiment is about 26.degree. C. in FIG. On the other hand, in FIG.

  When the vacuum is pulled with the hot water flowing through the heat exchanger and the water in the panel reaching a thermal equilibrium state, the water temperature in the panel is reduced by evaporation of the water in the panel when the vacuum is pulled, but the water temperature in the panel is originally stable. Therefore, the temperature distribution is small. On the other hand, when a vacuum is drawn when heat is transferred from the hot water flowing through the heat exchanger to the water in the panel, the water temperature in the panel becomes lower and a large temperature distribution is generated in the water in the panel. When boiling occurs in this state, the temperature of the bumping liquid is also not constant, and it is considered that the panel temperature could not be kept constant due to heat exchange between the bumping liquid and the panel in which the temperature difference occurred. Therefore, as one of the factors for stabilization, it is important to stabilize the water temperature in the panel during the vacuuming process.

  Next, the temperature difference between the lower part of the panel and the upper part of the panel in Experiment 10 and Experiments 13 to 19 where the water surface reaches the lower header pipe is compared. FIG. 22 shows the relationship between the thermostatic bath set temperature and the panel vertical temperature difference. From this figure, there is a tendency that the temperature difference between the top and bottom of the panel increases as the temperature of the thermostatic chamber increases. The vacuum boiling panel has the same pipe for moving steam and bumpy liquid to the upper part, and the pipe for moving condensed water to the lower part. It is hindered. The higher the hot water temperature, the more steam, bumping and condensing water will be generated, and this phenomenon will occur more often, hindering heat transport to the upper part of the panel and a large temperature difference between the lower and upper part of the panel. It is thought that it became.

When using a radiation panel, it is important for maintaining comfort that the user can set the panel temperature to his / her preferred temperature. Therefore, the relationship between the set temperature of hot water that exchanges heat with the water in the panel and the panel temperature was investigated.
Experiments 13, 14, 15, 17, 18 (hereinafter referred to as "night experiment" refer to these five experimental examples) and the average temperature of the panel which is the highest among the constant temperature chamber set temperatures in the night experiment. FIG. 23 shows the relationship between the thermostat set temperature in Experiment 10 in which the thermostat set temperature was increased by 5 ° C. every hour and the average temperature at the top, middle, and bottom of the panel. In Experiment 10, the temperature was set from 20 minutes to 60 minutes after setting the temperature of the thermostatic bath, which was considered to be sufficiently stable.
The plots in the night experiment of FIG. 23 are arranged on a substantially straight line, and the linear approximation is as shown in Equation (6.1).
Moreover, the approximate expression of the constant temperature chamber setting temperature and the panel average temperature in Experiment 10 can be expressed as Expression (6.2).

y = 0.79x-3.3 (6.1)
y = 0.81x-4.6 (6.2)

  In Experiment 10, the vacuum pump was used only at the start of the experiment, but it almost coincided with the panel average temperature of the night experiment in which the vacuum was pulled in each experiment, and the saturation state was maintained. The slopes and intercepts of Equations (6.1) and (6.2) are almost the same. If the temperature of the thermostatic chamber is increased by 1 ° C, the panel temperature can be increased by 0.8 ° C. Thus, the panel temperature can also be controlled by setting the thermostat temperature.

Next, let's look at the relationship between hot water temperature, panel water temperature, and panel average temperature. FIG. 24 shows the relationship between the water temperature in the panel and the average temperature at the top, middle and bottom of the panel in Experiments 13, 14, 15, 17, 18 (night experiment) and Experiment 10 where the average panel temperature was the highest.
In Experiment 10, when the hot water temperature was changed from 30 ° C to 50 ° C with the pressure inside the panel reduced, the water temperature in the panel increased by 16.1 ° C from 27.3 ° C to 43.4 ° C, and the average panel temperature increased from 20.1 ° C to 36.0 ° C. The temperature rose. In the night experiment, the water temperature in the panel rose 15.9 ° C from 27.4 ° C to 43.3 ° C, and the average panel temperature rose 14.8 ° C from 21.7 ° C to 36.5 ° C. Although the panel average temperature rise in the night experiment is a little small, when viewed as a whole, the temperature rise of the water in the panel is considered to be almost the same as the panel average temperature rise.

Further, looking at the amount of heat transfer from the hot water to the water in the panel, as shown in Table 5, the amount of heat received by the water in the panel increases as the temperature of the hot water increases. If the amount of heat received by the water in the panel becomes constant, the frequency of bumping increases with the amount of steam generated. If the condensing capacity on the panel surface is sufficient, the greater the amount of steam, the greater the amount of condensation, and more latent heat will be released, raising the panel temperature.
Since the water temperature in the panel and the average temperature of the panel are the same, the reduced-pressure boiling radiation panel is considered to generate a lot of heat transport due to bumping.

  In this way, the vacuum boiling radiation panel increases the amount of heat transferred from the hot water to the water in the panel by raising the temperature of the thermostatic chamber, the water temperature in the panel rises, and the panel heats up due to latent heat from steam and sensible heat from bumping liquid. It is possible to raise the temperature.

  The vacuum boiling spray panel can keep the panel temperature constant, and can control the panel temperature by changing the hot water temperature. Furthermore, the effect of the panel temperature on the indoor environment was examined.

In the nighttime experiment, the average temperature of the panels of Experiments 13, 14, 15, 17, and 18 where the average temperature of the panel was the highest among the temperature chamber set temperatures, and the average temperature of the upper, middle, and lower parts and “room temperature-outside temperature”, The relationship between the average room temperature and the average globe temperature is shown in FIG. 25. In Experiment 10, the average panel temperature from 20 to 60 minutes after setting the temperature of the thermostatic bath where the panel temperature is considered to be sufficiently stable is shown in FIG. The relationship among “room temperature-outside temperature”, average room temperature, and average globe temperature is shown in FIG.
From FIG. 25 and FIG. 26, it can be seen that if the panel temperature rises, the indoor environment is improved, and the temperature difference between the room temperature and the outside temperature on the experiment day shown in FIG. It can be seen that the reduced-pressure boiling radiation panel can improve the indoor environment by 5 ° C or more. Since Experiment 10 is a cloudy day and the outside air temperature hardly changes throughout the experiment, there is a correlation between the panel average temperature and all indoor environments as shown in FIG. On the other hand, in FIG. 25, since the outside air temperature differs depending on the experiment day, the correlation between the room temperature and the outside air temperature was correlated with the panel average temperature rather than the room temperature and the globe temperature alone.
The emissivity of the radiation panel used in this example is as small as about 0.1, but the radiation effect can be further improved by increasing the emissivity of the radiation panel.

  The heat radiation by the radiation panel is divided into a radiation heat radiation component and a convection heat radiation component. Each heat release is expressed by Equation (6.3) and Equations (6.4) to (6.9).

The heat release amount in Experiment 10 is shown in FIG. Looking at the amount of heat released at a hot water temperature of 50 ° C, the amount of heat released by radiation is 13.4 W / m ² and the amount of heat released by convection is 77.5 W / m ² , indicating that the amount of heat released by radiation is small. As described above, since the heat radiation due to radiation is reduced due to the low emissivity of the panel, the panel temperature can be maintained high due to the heat insulating effect of the panel, and the heat radiation due to convection is increased.

Here, we compare the floor heating, air conditioning running costs, and CO ₂ emissions, which are the most popular equipment using vacuum boiling panels and radiation. The unit price of electricity is 16.05 yen / kWh, the CO ₂ emission unit is 0.399 kg-CO ₂ / kWh, the unit price of gas is 122.19 yen / m ³ , and the CO ₂ emission unit is 2.21 kg-CO ₂ / m ³ .
Table 7 shows the running costs and CO ₂ emissions when each device is used for 8 hours a day for 1 month. The average power consumption measured on December 19, 2007 was used as the power consumption of the vacuum boiling radiation panel, and the running cost of the air conditioner was obtained from the rated power consumption during heating with a cooling capacity of 2.2 kW.

From Table 7, it can be seen that the running cost of the low-pressure boiling radiation panel is low and the CO ₂ emission is low. The heat required to operate a vacuum boiling solar panel may be covered by a vacuum boiling solar panel, which may further reduce running costs and CO ₂ emissions. Since the panel temperature of the vacuum boiling radiation panel can be stabilized at a high temperature, the effect on the indoor thermal environment can be enhanced by changing the experimental environment and the panel material, from the viewpoint of energy saving and environment It is valid.

Another example of the vacuum boiling radiation panel is shown in FIG. In this, the lower header portion of the panel is covered with warm water, and the heat exchanger and the radiation panel are integrated. Characteristically, the water enclosed in the panel is only the lower header part and a part of the narrow tube adhering to the panel, and the heat from the hot water is easily used for boiling the water.
As a further possibility of vacuum boiling radiation panels, this principle can be applied to the walls of houses.

  Hot water was used as the heat source for the vacuum boiling radiation panel, but the hot water temperature was raised to 46.2 ° C by a separate test combining a vacuum boiling solar panel and a heat storage tank in winter. The heat required to operate the vacuum boiling radiation panel can be sufficiently covered by solar heat. Therefore, a system that combines a vacuum boiling solar panel and a vacuum boiling radiation panel can be constructed. FIG. 29 shows a simulation result in which the amount of heat necessary for operating the vacuum boiling radiation panel at night is covered by the vacuum boiling solar panel. The vacuum boiling solar panel uses data from the condenser S2 on the test day, which had relatively high heat collection efficiency in the winter experiment, and the vacuum boiling radiation panel uses data from Experimental Example 13 (December 19, 2007) with an appropriate hot water temperature. It was. The radiation panel was started at 6pm and stopped at 6am so that the hot water temperature at 6am was maintained at 40 ° C. In addition, there is no heat loss from the heat storage tank, and all the heat obtained by the solar panel is stored in the heat storage tank.

  The total amount of heat collected by the vacuum boiling solar panel is used to raise the water in the heat storage tank from the initial water temperature of 10 ° C that day, and the amount of heat necessary to operate the radiation panel from 12 o'clock to 6 o'clock the next day. To cover it, the required heat storage tank capacity was about 108 L. Based on this determined amount of tank water, the maximum temperature of the hot water in the heat storage tank is calculated to be 45.6 ° C, which is below the hot water temperature confirmed in the boiling solar panel experiment. From this, combining the vacuum boiling solar panel and the vacuum boiling radiation panel, and the amount of heat required to operate the vacuum boiling radiation panel for 12 hours can be obtained from one solar panel, the effectiveness of this system can be demonstrated.

Incorporating as much natural energy as possible to create a society where people can live comfortably is the ideal form that can now be considered. FIG. 30 shows an example of a house where vacuum boiling is applied.
This house uses a vacuum boiling solar panel for the roofing material and a vacuum boiling solar panel for the wall material. In summer, an effect of suppressing an increase in surface temperature can be obtained by flowing cooling water from a cooling tower into a condenser of a vacuum boiling solar panel. Moreover, it can become a more effective system by processing the exhaust heat of an air conditioner through a cooling tower.

Basic form of vacuum boiling cooling and heat collecting device (Example 1) Schematic diagram of experimental apparatus Distribution graph showing measurement data of solar radiation and transpiration heat Example of computer cooling Example of application to solar snow melting equipment Example of application to vehicle cooling Example of application to an air conditioning partition System example described in Prior Literature 1 Example of solar thermal equipment described in Prior Literature 2 Device schematic Graph of temperature change in each part of Experiment 10 Graph of temperature change in each part of Experiment 11 Graph of temperature change in each part of Experiment 12 Graph of temperature change in each part of Experiment 13 Graph of temperature change in each part of Experiment 14 Graph of temperature change in each part of Experiment 15 Graph of temperature change in each part of Experiment 16 Graph of temperature change in each part of Experiment 17 Graph of temperature change in each part of Experiment 18 Graph of temperature change in each part of Experiment 19 Graph of temperature change of each part when pressure is not reduced Relationship between the temperature setting of the temperature chamber and the temperature difference between the top and bottom of the panel Temperature chamber setting temperature and average panel temperature Relationship between panel water temperature and panel average temperature Effect of panel average temperature on indoor environment during night experiment Effect of panel average temperature on indoor environment in Experiment 10 Heat dissipation from the panel in Experiment 10 Example of vacuum boiling panel Example of a system combining a vacuum boiling solar panel and a radiation panel Vacuum boiling solar panels-examples of houses with vacuum boiling solar panels

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum boiling cooling and heat collecting apparatus 2 Heat collecting part 3 Cooling part 21 Water cooling type computer cases 22a and 22b Heat collecting parts 23a and 23b Cooling part 31 Vacuum boiling cooling and heat collecting apparatus Solar snow melting devices 32a and 32b Heat collecting part 33a 33b Cooling unit 42 Heat collecting unit 43 Cooling unit 44 Porous body
45 Vacuum heat insulation panel 51 Panel for cooling and heating a vacuum boiling cooling / collecting device 52 Heat collecting unit 53 Cooling unit 54a-54z Vacuum vessel 55 Vacuum boiling cooling / collecting device 61 Room temperature 62 Globe temperature 63 Panel lower temperature 64 Panel middle temperature 65 Upper panel temperature 6 6 Hot water inlet temperature 6 7 Hot water outlet temperature 6 8 Lower header pipe temperature

Claims (6)

  A working fluid is sealed in a vacuum vessel and a vacuum vessel in a liquid phase and a gas phase, and the vacuum vessel is a vacuum boiling cooling / collecting device having a heat collecting part and a cooling part. A reduced-pressure boiling cooling / collecting device, wherein the cooling unit is set above the heat collecting unit.   The reduced-pressure boiling cooling / collecting device according to claim 1, wherein the heat collecting part is disposed adjacent to the heat generating part, and the cooling part is disposed on the outer surface of the device, and the heat dissipation from the inside to the outside Equipment equipped with a vessel.   The reduced-pressure boiling cooling / collecting device according to claim 1 is disposed on the roof surface, the cooling part is in contact with the snow stopper, and the heat collecting part is disposed on a lower slope continuous with the cooling part. A snow melting device for roofs, characterized in that the snow melting device is characterized. A mobile vehicle comprising the vacuum boiling cooling / collecting device according to claim 1,
An air conditioner for a moving vehicle, wherein the heat collecting part is arranged on a floor, a wall or the like on the inner surface of the vehicle, and the cooling part is arranged on a ceiling, a rear part or the like of the vehicle. A building equipped with the vacuum boiling cooling / collecting device according to claim 1,
An air conditioner for buildings, wherein the heat collecting part is arranged indoors and the cooling part is arranged outdoors.   A vacuum vessel and a vacuum vessel enclose a working fluid in a liquid phase and a gas phase in a two-phase state, and the vacuum vessel is a vacuum boiling cooling / collecting device having a heat collecting part on the lower side and a cooling part on the upper side, The cooling unit is capable of exchanging heat with the refrigerant, and the heat collecting unit is capable of exchanging heat with the heat medium.