阅读说明：本技术 一种可切换的无能耗制冷、制热热管理木材的制备方法 (Preparation method of switchable energy-consumption-free refrigeration and heating heat management wood ) 是由 梁大鑫 高鹤 谢延军 李坚 甘文涛 肖泽芳 程婉可 巴智晨 王文轩 于 2021-09-29 设计创作，主要内容包括：一种可切换的无能耗制冷、制热热管理木材的制备方法,本发明涉及改性木材的处理方法,它为了解决现有常规热管理方法能耗高,环境污染大的问题。处理方法：一、热管理木材的制备；二、预浸渍处理；三、热管理木材的模式切换。本发明所用的浸渍材料苯乙醇和乙醇均无毒,材料在辐射制冷和收集太阳光加热两个模式均有优异的光学性能,且兼顾了柔性和韧性,成本低廉的同时可自然降解。(The invention discloses a preparation method of switchable energy-consumption-free refrigeration and heating heat management wood, relates to a treatment method of modified wood, and aims to solve the problems of high energy consumption and large environmental pollution of the conventional heat management method. The treatment method comprises the following steps: firstly, preparing heat management wood; secondly, performing preimpregnation treatment; and thirdly, mode switching of the thermal management wood. The used soaking materials, namely the phenethyl alcohol and the ethanol, are nontoxic, have excellent optical properties in two modes, namely radiation refrigeration and sunlight collection heating, have flexibility and toughness, are low in cost and can be naturally degraded.)

1. The preparation method of the switchable energy-consumption-free refrigeration and heating heat management wood is characterized by comprising the following steps of:

preparation of heat management wood-0.5 wt% -3 wt% NaClO for preparing acetic acid buffer solution (pH 4.6)₂As a lignin removal solution, completely immersing the dried wood blocks into the lignin removal solution under the pressure of 10kPa for 5-24 hours; water bath at 80 deg.C5-24 hours, and replacing the solution every 2-5 hours. And then soaking the treated wood in water for 24-48 hours, and finally freeze-drying. Preparing a radiation refrigeration mode of the heat management wood;

and secondly, performing pre-impregnation treatment, namely soaking the thermal management wood in absolute ethyl alcohol for 5-20 minutes, and performing pre-impregnation treatment.

And thirdly, switching the mode of the thermal management wood, namely, after the material is fully soaked by the phenylethylene solution, the material becomes transparent and allows the sun to pass through, so that the solar heating mode of the thermal management wood is obtained. After the phenethyl alcohol is changed into the ethanol, the material turns white again, and the radiation refrigeration mode is changed again. The thermal management wood can be switched between radiant cooling and solar heating modes by alternating impregnation of ethanol and phenylethyl alcohol.

2. The method according to claim 1, wherein the wood in step one is wood or bamboo such as poplar, larch, pinus sylvestris, fraxinus mandshurica, rubberwood, etc.

3. The preparation method of the switchable energy-consumption-free cooling and heating heat management wood according to claim 1, wherein the water bath condition in the step one is that the water bath is carried out at the temperature of 90 ℃ for 3-12 hours.

4. The method for preparing switchable energy-consumption-free cooling and heating heat management wood according to claim 1, wherein the drying manner in the step one is ethanol, 50% ethanol/acetone solution and acetone are alternately dipped for 3 times (30 minutes each time), and finally air-dried.

5. The switchable energy-consumption-free cooling and heating heat management wood preparation method according to claim 1, wherein the phenethyl alcohol in the third step is a phenethyl alcohol/ethanol solution with an impregnation concentration of 50-100%.

Technical Field

The invention relates to a preparation method of switchable refrigeration and heating heat management wood without energy consumption.

Background

The worldwide demand for comfortable environments has made a widespread demand for cooling and heating of the interior of buildings and is currently the largest energy consumption of human society. Currently, commonly used methods of regulating temperature, cooling and heating technologies such as air-conditioning, have low cooling efficiency and high energy consumption, and aggravate the greenhouse effect and destroy the ozone layer. With the development of radiation refrigeration technology, energy-consumption-free cooling becomes a popular research, but the radiation refrigeration technology at the present stage has the problems that flexibility and strength cannot be considered, the cost is high, the degradation is difficult, the radiation refrigeration technology cannot meet different requirements on materials due to environmental temperature change, and the like, and meanwhile, the high heating cost in cold winter is also important energy consumption.

The patent with Chinese patent application No. CN 103287014B and name of selective absorption emission composite material satisfying solar heat collection and radiation refrigeration discloses a selective absorption emission composite material satisfying solar heat collection and radiation refrigeration, but the selective absorption emission composite material can only perform solar heat collection in the daytime and perform radiation refrigeration at night. The solar energy absorption device mainly aims at absorbing solar energy, does not have the capability of regulating and controlling the temperature of a building, and does not meet the requirement of people on heat management.

The patent with Chinese patent application number CN 107975895A and name "composite energy-saving device and method based on radiation refrigeration and phase-change energy storage" discloses a composite energy-saving device and method based on radiation refrigeration and phase-change energy storage, and the patent cannot give consideration to the flexibility and toughness of materials and is limited in application range. Meanwhile, the refrigeration and heating modes can only be changed without energy consumption according to the requirement.

The chinese patent application No. CN 109945363a, entitled "a radiation refrigeration system with temperature adaptivity and regulation method", discloses a radiation refrigeration system with temperature adaptivity and regulation method, wherein the polymeric radiation refrigeration material is difficult to degrade and has large environmental pollution, and only the radiation refrigeration effect is turned off in winter, and the polymeric radiation refrigeration material cannot effectively utilize solar energy to heat the space, and is not suitable for the environment requiring temperature rise.

Disclosure of Invention

The invention aims to provide a switchable preparation method of refrigeration and heating heat management wood without energy consumption, aiming at solving the problems of high energy consumption and large environmental pollution of the conventional heat management method.

The preparation method of the switchable energy-consumption-free refrigeration and heating heat management wood is realized according to the following steps:

preparation of heat management wood-0.5 wt% -3 wt% NaClO for preparing acetic acid buffer solution (pH 4.6)₂As a lignin removal solution, completely immersing the dried wood blocks into the lignin removal solution under the pressure of 10kPa for 5-24 hours; and (3) carrying out water bath for 5-24 hours at the temperature of 80 ℃, and replacing the solution every 2-5 hours. And then soaking the treated wood in water for 24-48 hours, and finally freeze-drying. Preparing a radiation refrigeration mode of the heat management wood;

and secondly, performing pre-impregnation treatment, namely soaking the thermal management wood in absolute ethyl alcohol for 5-20 minutes, and performing pre-impregnation treatment.

And thirdly, switching the mode of the thermal management wood, namely, after the material is fully soaked by the phenylethylene solution, the material becomes transparent and allows the sun to pass through, so that the solar heating mode of the thermal management wood is obtained. After the phenethyl alcohol is changed into the ethanol, the material turns white again, and the radiation refrigeration mode is changed again. The thermal management wood can be switched between radiant cooling and solar heating modes by alternating impregnation of ethanol and phenylethyl alcohol.

According to the invention, wood lignin is removed firstly, and then the heat management wood can be switched between a radiation refrigeration mode and a solar heating mode through alternate impregnation of ethanol and phenethyl alcohol. The heat absorption groups of the wood are removed along with the removal of the lignin, and meanwhile, the generation of multiple pores increases the scattering of sunlight by the material. The wood cellulose is used for realizing radiation refrigeration effect on high infrared radiation of 8-13 microns. When the material is impregnated with phenethyl alcohol with the same refractive index as cellulose, the transparency of the material is improved, the sun can be allowed to penetrate, and when the material is used as a roof material, the temperature of an indoor object can be increased.

The used soaking materials, namely the phenethyl alcohol and the ethanol, are nontoxic, have excellent optical properties in two modes, namely radiation refrigeration and sunlight collection heating, have flexibility and toughness, are low in cost and can be naturally degraded.

Drawings

FIG. 1 is a schematic diagram of the heat management wood obtained in the first embodiment, namely a heating mode (left) and a radiation cooling mode (right);

FIG. 2 is a scanning electron microscope of the surface of the poplar material used in the first step of the first embodiment;

FIG. 3 is a scanning electron microscope image of the surface of the heat-managed wood obtained in the first example;

FIGS. 4 and 5 are graphs of flexibility tests of the heat-managed wood obtained in the first example;

FIG. 6 is a graph of the tensile strength of the heat-managed wood obtained in the first example;

FIG. 7 is a graph of radiant cooling power of the heat-managed wood obtained in the first example;

FIG. 8 is a graph of the heating power of the heat-managed lumber obtained in the first embodiment;

FIG. 9 is a graph of outdoor temperature in summer for the heat-managed wood obtained in accordance with one embodiment, 1-wood material, 2-ambient air, 3-refrigeration state heat-managed wood;

fig. 10 is a graph of the outdoor temperature of the heat-managed lumber obtained in the first example in winter 1-heat-managed lumber in the heating state, 2-wood material, 3-heat-managed lumber in the cooling state;

fig. 11 is an infrared thermal imaging view of a room model made of the heat management wood obtained in the first embodiment just placed outdoors, 1-wood material, 2-heat management wood in a cooling state, and 3-heat management wood in a heating state;

fig. 12 is an infrared thermal imaging of a house model made of the heat management wood obtained in the first example, 1-wood material, 2-heat management wood in a cooling state, 3-heat management wood in a heating state, after being placed outdoors for 2 hours;

Detailed Description

The first embodiment is as follows: the preparation method of the switchable energy-consumption-free refrigeration and heating heat management wood in the embodiment is implemented according to the following steps:

preparation of heat management wood-0.5 wt% -3 wt% NaClO for preparing acetic acid buffer solution (pH 4.6)₂As a lignin removal solution, completely immersing the dried wood blocks into the lignin removal solution under the pressure of 10kPa for 5-24 hours; and (3) carrying out water bath for 5-24 hours at the temperature of 80 ℃, and replacing the solution every 2-5 hours. And then soaking the treated wood in water for 24-48 hours, and finally freeze-drying. Preparing a radiation refrigeration mode of the heat management wood;

and secondly, performing pre-impregnation treatment, namely soaking the thermal management wood in absolute ethyl alcohol for 5-20 minutes, and performing pre-impregnation treatment.

And thirdly, switching the mode of the thermal management wood, namely, after the material is fully soaked by the phenylethylene solution, the material becomes transparent and allows the sun to pass through, so that the solar heating mode of the thermal management wood is obtained. After the phenethyl alcohol is changed into the ethanol, the material turns white again, and the radiation refrigeration mode is changed again. The thermal management wood can be switched between radiant cooling and solar heating modes by alternating impregnation of ethanol and phenylethyl alcohol.

The first step of the implementation mode mainly plays a role in preparing the heat management wood, the acetic acid buffer solution is adopted for better treatment effect, and the damage to the strength of the wood is small. The second step is mainly used for pre-soaking and enhancing the infiltration effect of the material. And in the third step, the refractive index of the phenethyl alcohol is similar to that of the wood cellulose, the transparency is obviously enhanced after the phenethyl alcohol is soaked, and the high haze of the phenethyl alcohol enables the sunlight to uniformly enter a room and protects the internal privacy when the phenethyl alcohol is used as a roof material.

The second embodiment is as follows: the difference between the first embodiment and the second embodiment is that the wood in the first step is wood or bamboo such as poplar, larch, pinus sylvestris, fraxinus mandshurica, and rubberwood. Other steps and parameters are the same as those in the first embodiment.

The third concrete implementation mode: the first or second difference between the present embodiment and the specific embodiment is that the water bath condition in the first step is water bath at 90 ℃ for 3-12 hours. Other steps and parameters are the same as those in the first or second embodiment.

The fourth concrete implementation mode: the difference between this embodiment and one of the first to third embodiments is that the drying method in the first step is ethanol, 50% ethanol/acetone solution and acetone are alternately dipped for 3 times (30 minutes each time), and finally air-dried. Other steps and parameters are the same as those in one of the first to third embodiments.

The fifth concrete implementation mode: the difference between the present embodiment and one of the first to fourth embodiments is that the phenethyl alcohol in the third step is a phenethyl alcohol/ethanol solution with an immersion concentration of 50% to 100%. Other steps and parameters are the same as in one of the first to fourth embodiments.

The first embodiment is as follows: the preparation method of the switchable energy-consumption-free refrigeration and heating heat management wood in the embodiment is implemented according to the following steps:

first, preparation of thermal management Wood-1.5 wt% NaClO in acetic acid buffer solution (pH 4.6) will be prepared₂As the lignin removing solution, the dried wood piece was completely immersed in the lignin removing solution under a pressure of 10kPa for 10 hours; the water bath was maintained at 80 ℃ for 9 hours, and then the solution was changed every 3 hours. The treated wood was then soaked in water for 24 hours and then freeze-dried. Preparing a radiation refrigeration mode of the heat management wood;

and secondly, performing pre-impregnation treatment, namely soaking the thermal management wood in ethanol for 5 minutes to perform the pre-impregnation treatment, so that the infiltration effect of the material is enhanced.

And thirdly, switching the mode of the thermal management wood, namely, after the material is fully soaked by the phenylethylene solution, the material becomes transparent and allows the sun to pass through, so that the solar heating mode of the thermal management wood is obtained. After the phenethyl alcohol is changed into the ethanol, the material turns white again, and the radiation refrigeration mode is changed again. The thermal management wood can be switched between radiant cooling and solar heating modes by alternating impregnation of ethanol and phenylethyl alcohol.

In the present embodiment, fig. 3 is an SEM image of the surface of the heat management wood, and it can be seen from comparison with fig. 2 that the cell walls and intercellular layers of the wood are both damaged, which not only increases the scattering of sunlight but also increases the specific surface area, and improves the wettability. The good flexibility of the material (radius of curvature 4mm) and at the same time the good strength (fig. 6) are illustrated by fig. 4 and 5. The reflectivity of the material in a spectral range of 250-2500 nm is 95.9% under a radiation refrigeration state, and meanwhile, the infrared radiance in an infrared spectral range (2.5-25 mu m) is 0.93. FIG. 7 shows that the material has excellent cooling effect and the cooling power is 81.4W/m². In the heated state, the material possesses high transparency with a light transmission of 81.3%. FIG. 8 shows the collected solar radiation heating capacity of the material at 229.5W/m heating power in the winter solstice of Harbin²This indicates that the material has excellent cooling and heating effects. Fig. 9 and 10 are temperature diagrams of the heat management wood, the wood material and the ambient air outdoors in summer and winter, respectively, in fig. 9, the temperature of the heat management wood in the refrigeration state is lower than the ambient air throughout the day, the average temperature is reduced to 4.5 ℃ in the daytime, and the temperature can be reduced to 5.3 ℃ at night, so that the excellent refrigeration effect is achieved. In fig. 10, the temperature of the heat-managed wood in the heated state can be raised by 5.6 degrees by transmitting light, and the heating performance is excellent. We have made house models, shown in fig. 11 and 12, and from the infrared thermography, we can see that after 2 hours outdoors, this excellent performance is present in both states of the invention. The invention adopts the method of dipping the solvent for conversion, and is simple and easy to operate. The material used in the invention is biodegradable and environment-friendly.