JPH035772B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal storage heating method and apparatus using solar heat, which is particularly suitable for heating greenhouse cultivation rooms such as agricultural greenhouses and mushroom cultivation rooms. The amount of petroleum consumed in agricultural greenhouses is enormous, and as an energy-saving measure, storage of solar heat underground has been put into practical use. This system involves burying a large number of vinyl chloride pipes underground, and circulating high-temperature air inside the greenhouse during the day using a blower to raise the temperature on the ground of the greenhouse, which has a large heat capacity. The amount of stored heat is extracted by introducing and circulating air.
However, with this heat storage method, the humidity inside the greenhouse becomes abnormally high at night due to condensed water inside the PVC pipes, causing a large amount of condensation on plants such as tomatoes and cucumbers, which can cause various diseases. Disadvantages include the fact that the carbon dioxide concentration decreases during heat storage, and that there is little hope, especially in winter, in regions where the daytime temperature does not rise and there is not much difference between the temperature inside the greenhouse and the underground temperature. It was hot.

The present invention has been made in view of the above circumstances, and the present invention is an improvement in that the conventional method uses solar heat to store heat underground, which has a large heat capacity, or in other words, stores heat by sensible heat. In contrast, the method of the present application uses a material that selectively absorbs moisture in the air to absorb moisture from the relatively humid air in the greenhouse at night and dry it appropriately, and also allows water vapor to condense in the moisture absorbing material. The condensation heat released when the water is heated, and the wetting heat generated when the condensed water adheres to the moisture absorption material, raise the air temperature and heat the greenhouse. It performs desorption and regeneration, and mainly uses latent heat, as opposed to the sensible heat used in geothermal systems.

In the present method and apparatus, sensible heat is naturally accumulated in the moisture absorbing material due to its heat capacity proportional to its specific heat, but compared to latent heat, the effect is approximately 1/6 to 1/10. Therefore, the explanation will be omitted in the future description along with the wetting heat. Hereinafter, a detailed description will be given based on one embodiment of an apparatus for carrying out the present method.

The moisture absorbing material used in the present method is preferably a substance that can selectively absorb water vapor in the air.
In that sense, synthetic materials used as molecular sieves are ideal, but on the other hand, since the purpose of the present method is to serve as an alternative to petroleum energy, synthetic materials are expensive. Obviously, it cannot be used as a moisture absorbent material in the present method and apparatus. The inventor of the present application has investigated materials that have selective water absorption ability and is also economically efficient, and has found that natural zeolite and Kanuma soil, which have been subjected to a certain activation treatment, meet these requirements. We have found that mordenite is the most suitable. In addition to the above, silica gel, alumina gel, or porous materials impregnated with highly hygroscopic substances, such as calcium chloride, lithium chloride, glycols, etc., can be used in the present method. Can be used as a moisture absorbent. In the above, porous materials are those that serve as carriers for chemical substances, such as diatomaceous earth, pumice, and bricks.
Activation treatment is in the range of 150℃ to 500℃,
This means firing for at least 30 minutes or more, and this treatment hardens the pores of the zeolite and imparts selective moisture absorption ability. 150℃
In the following, this effect can hardly be expected, and about
At temperatures above 500℃, tissue destruction occurs, which also causes
loss of absorption capacity. It is desirable to activate silica gel and the like at 150°C to 250°C. These moisture absorbing materials are crushed or molded into appropriate sizes, and the size is determined in relation to the output of the blower, which will be described later. It goes without saying that only one type of moisture absorbing material may be used, or they may be used in appropriate combinations. Such a hygroscopic material 1 is filled into a certain hygroscopic material chamber 2 from an airtight container provided with an air inlet/outlet. The moisture absorbing material chamber 2 only needs to be airtightly separated from the surrounding environment, and does not necessarily need to be buried underground. However, from the viewpoint of effective use of the ground surface, it is necessary to install it underground, or
Surrounding the device with insulation or the like is desirable as it prevents heat from being lost to the outside environment. In order to fully exhibit the effects of the method and device of the present invention, at least the ceiling of the greenhouse 3,
Preferably, a transparent body 3c is stretched around the entire periphery with a slight space between them to create a double structure, and a large amount of water vapor from the ground surface, plants, etc. inside is stored in the heat collection chamber 3a, which is the outer compartment. It is preferable to prevent the air contained in the cultivation room 3b from entering. When using this device to heat a mushroom cultivation room, etc., either make the roof of the mushroom cultivation room transparent and use the attic as a heat collection room, or use a radiator to radiate the solar heat absorbed by a solar water heater. As a result, air whose temperature has been increased may be used, and in the present application, the term "heat collection chamber" includes the case where such secondary heated air is sent out. An intake pipe 4 is installed in the upper part of the heat collection room 3a and the upper part of the cultivation room 3b.
a, 4b are arranged and open, and these intake pipes 4a, 4b are connected to a blower pipe 6 via a flow path switching valve 5, and this blower pipe 6 is connected to a blower pipe 6 via a blower 7. It is connected to a perforated pipe 2c that blows out air, which is installed in the moisture absorbent material 1 in the moisture absorbent chamber 2.

On the other hand, the exhaust pipe 8 that opens into the upper space in the moisture absorbent chamber 2 branches into two branches via a flow path switching valve 9, one branch pipe 10a opens into the atmosphere, and the other branch pipe 10b, It opens into the cultivation chamber 3b.

An outline of the operating method of the apparatus configured in this way will be described first. Air in the heat collecting chamber, which has risen due to sunlight, is sent into the moisture absorbing material chamber 2 by the blower 7. The relative humidity of the introduced air is significantly reduced due to an increase in temperature due to solar heat, which promotes desorption and evaporation of moisture from the moisture absorbent material. Air in the heat collection room is supplied from an outside air intake (not shown) provided at the bottom of the greenhouse. The air passing through the moisture absorbing material chamber has a lower temperature and an increased humidity due to heat of evaporation, etc., so it is introduced into the cultivation chamber 3b only when necessary, and most of it is released into the atmosphere from the branch pipe 10a. be done. The moisture-absorbing material whose moisture-absorbing ability has been regenerated in this manner can retain its moisture-absorbing ability for a considerable period of time by closing the on-off valves 11 and 12. Next, when the temperature inside the greenhouse drops at night, the air inside the greenhouse contains a large amount of water vapor supplied from the soil, plants, etc., so the relative humidity approaches 100% and condensation occurs. begins to occur.

By switching the flow path switching valve 5, such humid air is sent into the heat storage chamber from the intake pipe 4b. Here, water vapor in the air is absorbed by the moisture absorbing material and condensed, releasing heat of condensation. Therefore, after leaving the moisture absorbing material chamber, the flow path switching valve 9 and the branch pipe 1
Since the air returning from 0b into the greenhouse is suitably dried and has a raised temperature, a drop in temperature and condensation inside the cultivation room are prevented. The blower is normally operated in conjunction with a thermostat so that the blower operates within a set temperature range.
The natural zeolite used as the hygroscopic material in this application is:
For example, borazite, borozite, borozite,
Examples include soda zeolite, sulfate zeolite, and morden zeolite. These activated natural zeolites have a selective adsorption ability for carbon dioxide gas, and this adsorption equilibrium is mainly dependent on temperature, so when exposed to high temperature air during the day, Since carbon dioxide gas is released into this gas and adsorbed at night, it also has the secondary effect of adjusting the carbon dioxide concentration within the cultivation room.

As mentioned above, the heating method of the present invention is highly dependent on the moisture absorption ability of the moisture absorbent material, in other words, the relative humidity of the air that expels moisture from the moisture absorbent material and regenerates it. As is well known, if the absolute humidity is constant, the relative humidity will drop by about half as the air temperature rises by about 10 degrees Celsius. When outside air is taken into the heat collection chamber and its temperature rises, the relative humidity decreases, and when this air is introduced into the moisture absorption material chamber, moisture is desorbed and evaporated from the moisture absorption material. Therefore, in the present method, even on a mid-winter day when the outside air temperature during the day is around -2°C and it is cloudy, the temperature in the heat collection room often rises to 10°C or more during the day. This air regenerates the hygroscopic material, and at night, it is possible to generate and utilize the corresponding heat of condensation. This point is significantly different from the geothermal method, which requires that the air temperature inside the greenhouse be higher than the soil temperature (normally, it cannot be expected to be effective unless it is 10 to 15 degrees Celsius higher than the soil temperature). In addition to the above-mentioned features, the present invention has the ability to adjust carbon dioxide gas content and prevent condensation inside the greenhouse compared to conventional geothermal systems. However, with the geothermal method, it is not easy to move, but in the case of the present invention, underground equipment is not an essential requirement. Installation and movement are extremely easy, and the on-off valves 11a, 12a, 11b, 12b
By connecting several isolated and independent moisture absorption material chambers 2a and 2b in parallel, it is possible to release and conserve moisture on days when conditions are good, and to store it on days when conditions are bad. It can function as a preliminary heating capacity. Examples are listed below.

[Example] A vinyl sheet tent was set up at a distance of 0.5 to 1.0 m from the outer wall and roof surface in a glass greenhouse (7 m long, 9 m wide, 5 m high) installed in Nagano City to collect heat. The experiment was conducted from mid-November to the following February using a heating device almost identical to that shown in Figure 1. The moisture absorbing material is a fist-sized piece of mordenite heated to 200°C.
Fill the moisture absorbing material chamber with 1000 kg of the material that has been baked at a similar temperature for 1 hour, and around the moisture absorbing material chamber,
cm wrapped in Styrofoam and used outdoors. On the other hand, as a control, a pipe with a diameter of 10 cm was extended 60 cm underground in a greenhouse of approximately the same size and structure.
The device was buried for 210 meters and was continuously blown at a rate of 60 cubic meters per minute.
The moisture removal process was carried out by continuously blowing air for about 7 hours. In addition, regarding the ventilation time during the moisture absorption process at night, in both cases, the blower is set to a thermos so that when the temperature inside the cultivation room falls below 5℃, the ventilation (moisture absorption process) starts, and when the temperature rises to 7℃, the ventilation stops. It was controlled by Tatsuto. As a result, during the period, the temperature in the greenhouse dropped to 2°C in the control area, but did not drop below 6°C in the greenhouse equipped with the device of the present invention. The amount of heat stored and the amount of heat released by the method of the present application are as follows:
The outline can be understood from the water vapor-active mordenite adsorption equilibrium diagram shown in the figure. For example, when the temperature of the hygroscopic material is 8°C and the equilibrium moisture content is 14% (point A in Figure 3), the hygroscopic material is regenerated with air at 33°C and 25% humidity; Moisture content
Stop regeneration at 10.5% (point C), then lower the humidity to 5℃.
If 100% of the air is sent and the heat of condensation is extracted, the equilibrium in Figure 3 is approximately A→B→C.
It can be considered that the movement occurs in a cycle such as →D→A′, and therefore, the length of line segment A′B (and DC) corresponds to the sensible heat accumulated (and heat dissipated), respectively.
The distance between line segment A′B and line segment DC corresponds to the accumulated (radiated) latent heat, and the amount of heat storage is determined by the specific heat and heat of evaporation (heat of condensation) per unit scaled on the upper and right sides of Figure 3. , it is easy to estimate the amount of heat dissipation.

[Test Example] In order to verify the moisture absorption ability of the moisture absorbing material of the present invention, as shown in FIG.
was filled with 20 g of synthetic zeolite soaked in a 20% calcium chloride aqueous solution and then drained (weighing 37.5 g) as the moisture absorbing material 43, and the temperature at the inlet W and outlet X was measured using a wet/dry thermometer 44. Then,
Dry bulb temperature Y and wet bulb temperature Z were measured, absolute humidity was calculated from Y and Z, and relative humidity at W and X was calculated. P is a suction pump, and the air volume is 4/
It was set to minutes.

The test was run for 8 hours as a moisture release process, and the temperature of the constant temperature and humidity chamber 41 was 56 to 51℃, and the relative humidity was 24.4 to 38℃.
%, and the moisture absorption step was carried out at a constant temperature and humidity chamber temperature of 3.5 to 5° C. and a relative humidity of 84 to 90%, and the operating time was 14.5 hours. The results are shown in Figure 5.

As is clear from this, in the moisture release process, the outlet temperature is lower than the inlet temperature, and the difference gradually decreases to near 0, and the outlet relative humidity is greater than the inlet relative humidity, and water vapor In the moisture absorption process, this relationship is reversed, and the opposite phenomenon occurs in the moisture release process, indicating that heat is being released.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing an embodiment of the present invention device. FIG. 2 is an explanatory diagram showing the main parts of the apparatus shown in FIG. 1. FIG. 3 is a water vapor-active mordenite adsorption equilibrium diagram. FIG. 4 is a conceptual diagram showing an outline of a moisture absorption performance testing apparatus for the moisture absorbent material of the present invention. Fifth
The figure is a graph showing test results using the apparatus of FIG. 4.

Claims (1)

[Scope of Claims] 1. Natural zeolite, Kanuma earth, silica gel, alumina gel, or porous substances activated by firing in a certain temperature range, and highly hygroscopic chemicals such as calcium chloride, lithium chloride, and glycols. By filling one or more of the hygroscopic materials impregnated with an aqueous solution of the hygroscopic material into a hygroscopic material chamber consisting of an airtight container having an air inlet/outlet, and supplying air that has become high in temperature and low in humidity due to solar heat into the hygroscopic material chamber. , promotes the desorption of water from the moisture absorbent material, and when greenhouse heating is required such as at night, the air with high relative humidity inside the greenhouse is circulated through the moisture absorbent room, and water vapor selectively absorbed by the moisture absorbent material is generated. A method for storing and heating a greenhouse using solar heat, which is characterized by extracting condensed heat when condensing. 2. The regenerative heating method according to claim 1, wherein the activation treatment is baking at a temperature in the range of 150°C to 500°C for at least 30 minutes or more. 3. The regenerative heating method according to claim 1, wherein natural mordenite calcined at 150°C to 500°C for 30 minutes or more is used as the moisture absorbing material. 4 Air intake pipes opening into the solar heat collection room and the cultivation room are connected to the blower pipe via a flow path switching valve,
The air pipe is used to inject highly hygroscopic chemicals such as calcium chloride and lithium chloride into porous materials such as activated natural zeolite, Kanuma soil, silica gel, alumina gel, or porous materials into an airtight container through an air blower. , an exhaust pipe connected to a moisture absorbent chamber filled with one or more moisture absorbent materials impregnated with an aqueous solution of glycols to blow air to the moisture absorbent material, and having one end opened in the moisture absorbent chamber. , a heating system for a greenhouse using solar heat, which branches into two via a flow path switching valve, with one branch pipe opening into the atmosphere and the other opening into the cultivation room. 5. The heating device according to claim 4, wherein the moisture absorbing material chamber is covered with a heat insulating material. 6. The heating device according to claim 4, wherein the activation treatment of the hygroscopic material is baking at a temperature in the range of 150°C to 500°C for at least 30 minutes.