4258 results about "Anti freezing" patented technology

The invention discloses a plant polysaccharide cigarette filter tip and a preparation method thereof. Plant polysaccharide, starch, adsorbent, plasticizer, emulsifier, waterproofing agent and plant protein are blended according to a certain proportion, so that the filter tip is prepared. The preparation method includes the following steps: (a) the starch, water and the plasticizer are blended and stirred, so that modified starch solution is obtained; (b) the plant polysaccharide and the modified starch solution are blended; (c) under certain conditions, the emulsifier, the waterproofing agent and the adsorbent are added into the mixture of the plant polysaccharide and the modified starch solution, and after stirring, the mixture is injected into a long cylindrical mold made of anti-freezing, heat-proofing material and molded; (d) the semifinished product is placed into a freezing environment and frozen, i.e. prefreezing; (e) the semifinished product in step d is placed into a freeze dryer and freeze-dried; (f) the porous composite body is taken out of the mold and deburred, and thereby a filter tip stick is obtained. Material resources are rich, the cost is low, and the three wastes cannot be produced. The performance is good, the filter tip can reduce the nicotine content by 40.2 to 84.1 percent, the tar by 26 to 72.1 percent and the nicotinamide by 20 to 39.2 percent, and after use, waste can be biodegraded.

The invention belongs to the field of super-hydrophobic or super-amphiphobic coating preparation, and particularly relates to a method for preparing durable super-amphiphobic coatings capable of being sprayed. The method particularly includes steps of 1, carrying out cleaning and sand blasting roughening treatment on the surfaces of base materials; 2, preparing resin solution; 3, preparing particle composite suspension; 4, spraying the resin solution obtained at the step 2 on the surfaces, treated at the step 1, of the base materials, drying the base materials and carrying out semi-solidification on resin adhesive; 5, spraying the particle composite suspension obtained at the step 3 on the surfaces of the base materials obtained at the step 4, and drying the base materials to completely solidify the base materials; 6, washing the surfaces of the base materials obtained at the step 5 to obtain the durable super-amphiphobic coatings capable of being sprayed. The method has the advantage that the durable super-amphiphobic coatings with excellent durability and firmness can be prepared on the surfaces of the various base materials by the aid of spraying technologies and have persistent anti-freezing performance.

A water nan-composite thermal-insulating coating for external wall and its production are disclosed. The coating consists of water, polymer emulsion, high-refractive index pigment, filler, nano-tin-antimony oxide slurry, nano-SiO2, wet dispersant, filming accessory, pH adjuster, thickener, de-foaming agent, anti-freezing agent and mildew-proof bactericide. It's cheap and simple, has excellent wash and weather resistances, better thermal-insulating performance, safe storage and no environmental pollution. It can be used for apparatus surface and architecture external wall.

The invention discloses foam concrete and a preparation method thereof. The foam concrete comprises a gelling material, light aggregate, water, admixture and foaming agent. The preparation method comprises the following steps: (1) pre-treating raw materials to prevent hard lumps and hard grains in the raw materials from depositing in foam slurry; (2) weighing each component according to a proportion; (3) preparing and adding foaming solution; (4) loading and stirring, namely, adding water into a stirrer, starting the stirrer, and adding cement, coal ash, perlite, waterproof agent, anti-freezing agent, water reducing agent and fiber into the stirrer in turn; (5) foaming, namely, foaming at the same time of stirring the slurry, sealing a valve firstly and then pressurizing the valve by an air compressor; (6) adding foam, namely, after the gelling slurry is well prepared, adding the foam into the gelling slurry under the state of stirring without stopping the stirrer; and (7) casting and molding, namely, when the slurry surface has no floating foam, finishing the preparation of the foam slurry. The foam concrete has the functions of light weight, water proofing, fire resistance, heat insulation, freezing resistance, cracking resistance, shock resistance and the like, and is particularly suitable for engineering insulating layers in cold areas and water-blocking and shock-resistant layers of underground engineering.

A hot-water supply apparatus is an apparatus which has a primary heat exchanger absorbing sensible heat of combustion exhaust and a secondary heat exchanger absorbing latent heat of the combustion exhaust, and improves a freezing prevention function of the hot-water supply apparatus at a cold period. Further, this apparatus has a temperature detection means (temperature sensors) which detects a freezing prevention temperature, a combustion means (a burner group) which supplies combustion exhaust generated by combustion to the primary and secondary heat exchangers, an air supply means which supplies air to the combustion means, and a control means (a control unit) which makes the combustion means burn and drives the air supply means based on a detected temperature of the temperature detection means. When the temperature detection means detects the freezing prevention temperature, the combustion means is burned for a settled time to heat the primary heat exchanger, and the air supply means is driven to stream air from a side of the primary heat exchanger to the secondary heat exchanger for a given time after a combustion stop of the combustion means. By this, a side of the secondary heat exchanger is heated by remaining heat of the side of the primary heat exchanger.

The invention discloses a multifunctional composite seed coating agent, which is a crop seed treatment agent prepared by mixing active ingredients such as pesticides, fertilizers, plant growth regulators and the like with inactive ingredients such as film forming agents, emulsifying agents, dispersing agents, anti-freezing agents, defoaming agents, antiseptic agents, PH value regulators, pigments and the like. The invention not only can effectively prevent and control plant diseases and insect pests in the seedling stage but also can promote and control seedling growth, ensures that seedlings grow regularly and luxuriantly with multiple tillers, and obviously improves the seedling survival rate. The traditional method can be used for soaking coated seeds in flowing water to accelerate germination for carrying out water breeding, dry breeding or direct seeding, and the coated seeds can be stored safely.

The invention provides an anti-freezing control method and device. The anti-freezing control method comprises the steps: detecting an indoor ambient temperature and the temperature of a coil pipe in an indoor machine heat exchanger; increasing the rotation speed of an indoor machine direct-current fan from a preset initial wind speed when the indoor ambient temperature is in a first preset temperature range and the temperature of the coil pipe is in a second preset temperature range. According to the method, the frequent starting and stopping of a compressor during anti-freezing control can be reduced; moreover, effectiveness in refrigeration can be realized, the refrigerating effect can be guaranteed, and the service life of the outdoor compressor can be guaranteed.

The invention discloses a flight control auxiliary. A formula of the flight control auxiliary comprises components in percentage by mass as follows: 50%-65% of an anti-drifting agent, 5%-10% of a wetting agent, 5%-10% of a penetrating agent, 1%-2% of a viscosity modifier, 3%-5% of a deposition agent, 2%-4% of an anti-freezing agent and the balance of water. The flight control auxiliary is applicable to dosage forms such as a suspending agent, an oil suspension, a water agent, emulsion in water, microemulsion and dry flowable for flight control. The flight control auxiliary has functions of remarkably resisting drifting, accelerating sedimentation, increasing moisture and improving chemical absorption when applied to flight control operation.

The invention discloses an anti-freezing control method for an air conditioner heat exchanger. The control method comprises the steps of acquiring an pipe temperature T1 of an indoor heat exchanger; determining a preset temperature region where the pipe temperature T1 of the indoor heat exchanger is located and a time threshold value N1 corresponding to the temperature region; recording the accumulated time t1 when the pipe temperature of the indoor heat exchanger is continuously positioned in the determined temperature region; if the determined accumulated time t1 is longer than or equal to the time threshold value N, controlling an outdoor unit of an air conditioner to stop running and an indoor unit to enter a defrosting mode. The invention also discloses an anti-freezing control device for the air conditioner heat exchanger. The low-temperature refrigeration effect of the common air conditioner can be achieved without a low-temperature refrigeration device, and a refrigeration demand for extremely low temperature of an outdoor environment is met; furthermore, multiple conditions for entering the defrosting mode are set, and each condition corresponds to different defrosting parameters, so that high-efficiency defrosting can be realized, and resources are effectively used.

The invention discloses multifunctional waterproof antiseptic aldehyde-eliminating glue, and belongs to the technical field of construction materials, wherein the glue is mainly for sealing, waterproofness, moisture-proofness, anticorrosion, mold prevention, insect prevention, termite prevention and aldehyde elimination of materials such as bamboo wood, timber, rattan wood, wall faces, ground, emulsion varnish, wallpaper, floor boards and wooden doors. The multifunctional waterproof antiseptic aldehyde-eliminating glue is characterized by comprising 10-90 parts of water-dilutable resin, 0.01-30 parts of antiseptic and mold inhibitor, 0.01-20 parts of insect-resist agents, 0.01-15 parts of termite-resisting agents, 0.1-20 parts of aldehyde-eliminating agents, 0.1-30 parts of coalescing agents, 0.5-15 parts of anti-freezing agents and 5-95 parts of water. After being treated by the multifunctional waterproof antiseptic aldehyde-eliminating glue, products are strong in engaging force, environment-friendly, water-proof, moisture-proof, antiseptic, mold-proof, inset-proof, termite-proof and capable of eliminating aldehyde. Meanwhile, construction is easy and convenient. Besides, the invention further provides a preparation method of the multifunctional waterproof antiseptic aldehyde-eliminating glue.

The invention discloses a kiwifruit tree planting method. Connected greenhouses are used for cultivation, greenhouse films and arrangement of the greenhouses are adjusted along with change of seasons, the four-prevention measures including anti-freezing measures taken in winter and spring, rain sheltering and disease preventing measures taken in the rainy season, and cooling and sun blocking measures and windproof measures taken in midsummer are adopted, matched labor-saving tree cultivating management is performed, the capacity for coping with extreme weather in rainy and high-temperature areas in the south is effectively improved, and the high temperature and high humidity disease problem and the like which are difficult to solve in open field cultivation and traditional facility cultivation are solved. Due to the adoption of the method, the kiwifruit disease transmission route can be effectively cut off, input cost is low, manpower is saved, the survival rate of kiwifruit trees reaches 95.2%, the average single weight of red kiwifruits can reach 86 g under the situation that no swelling agents are applied, and the largest single fruit weight reaches 103.5 g; the soluble solid reaches 17.4% to 19.1%; the fruit cleanness is obviously improved, use of swelling agents and high-poison and mediate-poison pesticide is effectively eradicated, and quality safety of the fruits is guaranteed.

The invention discloses a water-based capillary crystalline type waterproof material with the controllable reaction speed as well as a preparation method and an application of the waterproof material. The waterproof material is mainly prepared from raw materials in parts by weight as follows: 30-40 parts of sodium silicate, 0.05-0.15 parts of a surfactant, 0-1 part of a reaction retarder, 0.1-0.2 parts of a reducing agent, 0-5 parts of a reaction accelerant, 0.06-0.1 parts of an anti-freezing agent, 0.1-0.3 parts of a metal ion blocking agent, 0.4-0.8 parts of a surface enhancer, 0.2-0.4 parts of an antirust agent and 53-69 parts of deionized water. The waterproof material has properties of lasting water resistance, durability, aging resistance, good permeability resistance, cracking resistance, high seepage capacity and the like and can reach the optimal waterproof effect for concrete under different porosity conditions; besides, the preparation method is simple, low in cost, pollution-free and convenient to conduct in concrete waterproof application.

The present invention belongs to the field of pasture plant cultication technology, in the concrete, it relates to a cultivation method capable of raising drought resistance of Lucerne and protecting Lucerne from winter freezing injury. Said method includes the following steps: selecting cold resistant variety, setecting field, weeding and fertilizer application, ridge forming, ridge-seeding and field management.

The invention relates to a method to improve the antifreeze ability for air condition. It includes the following steps: minimum water flow would be controlled by a flow controller at water outlet, setting an antifreeze value, when water temperature lowering than the value, the set would stop running and output alarm. If the water temperature at water intake is lower than a set temperature value, and the temperature difference at outlet and intake exceeding a set value, and lasting for a time span, it would be judged as not enough water flow. The machine would be stopped and output alarm.

A puncture sealing agent for a tire is disclosed that has a rubber latex, an adhesive agent, and an anti-freezing agent, wherein glycerin, potassium acetate or a solution of glycerin and potassium acetate is used as the anti-freezing agent.

An air-conditioning apparatus has at least one intermediate heat exchanger that exchanges heat between a refrigerant changing in two phases or a refrigerant in a supercritical state and a heat medium such as water and anti-freezing fluid different from the refrigerant, a refrigeration cycle in which a compressor, a heat-source side heat exchanger, at least one expansion valve, and a refrigerant-side channel of the intermediate heat exchanger are connected via a pipeline through which the refrigerant flows, and a heat-medium circulation circuit in which a heat-medium side channel of the intermediate heat exchanger, a pump, and a use-side heat exchanger are connected via a pipeline through which the heat medium flows, in which in the heat-medium circulation circuit, a fourth temperature sensor that detects a temperature of the heat-medium flowing out of the use-side heat exchanger is provided, and leakage of the heat medium from the heat-medium circulation circuit is detected on the basis of a change amount of a detected temperature of the fourth temperature sensor.

The invention discloses an environmentally-friendly photocatalyst air freshening inner wall coating and a preparation method thereof. The coating comprises the following raw materials in percentage by weight: 20-40 percent of silicone-acrylic emulsion or ethylene-acrylic acid copolymer emulsion, 1-5 percent of anatase-phase nano-titanium dioxide, 2-2.5 percent of negative ion generating material, 1-2 percent of wetting agent, 0.5-1 percent of dispersing agent, 1 percent of preservative, 1 percent of pH regulating agent, 1-2 percent of anti-freezing agent, 1-2.5 percent of diatomite, 1-2 percent of film forming aid, 1-2 percent of thickening agent and the balance of water. In the coating, a photocatalysis material and the negative ion generating material are used, so that indoor air pollution can be eliminated effectively, and the coating has the advantages of stable lasting effect and avoidance of secondary pollution.

The invention provides a preparation method of high-strength, anti-freezing and conductive chitosan / acrylamide dual-network hydrogel. A first network and a second network interpenetrate to form the chitosan / acrylamide dual-network hydrogel. The first network is physical entanglement or physical crosslinking hydrogel formed by chitosan molecular chains under the action of inorganic salts with different valence states. The second network is hydrogel formed by chemically crosslinking acrylamide. Based on modifiable sites of chitosan, chitosan / acrylamide semi-interpenetrating hydrogel is soaked ininorganic salt solution with different concentration to induce chitosan to form the physical crosslinked network hydrogel. Therefore, the hydrogel achieves good mechanical properties, freezing resistance and conductivity. The highest tensile strength of the hydrogel can reach 450kPa, the hydrogel can still keep a soft state at the temperature of 20 DEG C below zero, the highest conductivity of the hydrogel can reach 200mS / cm, and the application field of the hydrogel is widened.

The invention discloses water-soluble nano camouflage paint and a preparation method thereof, belonging to the technical field of wave-absorption paint. The water-soluble nano camouflage paint is prepared from the following components in percent by mass: 20%-60% of water-soluble resin, 2%-6% of a silane coupling agent, 24%-40% of wave-absorbing particles, 1.5%-2.0% of a protective agent, 2%-4% of an emulsifier, 4%-6% of an anti-freezing agent, 0.1%-0.5% of a defoaming agent and the balance of deionized water. According to the invention, the water-soluble resin is used as a carrier of components such as a film forming matter and a wave-absorption material and the deionized water is used as a diluent, so that harms of an organic solvent in the camouflage paint on a human body and an environment are completely avoided, and therefore, the water-soluble nano camouflage paint is environment-friendly type paint in true sense.

The invention discloses a preparation method of a self-adhesive hydrogel having anti-freezing / heat-resistant performance. The method adopts a hydrogel solvent system consisting of glycerin and a watermixed system, and powerful hydrogen-bond interaction between glycerin and water enables water to be stably immobilized in a polymer network, can destroy the formation of ice crystal lattices at a lowtemperature and prevent moisture volatilization at a high temperature, and endows the hydrogel with long-term stability, anti-freezing performance and heat resistance. Besides, synergy between polydopamine, glycerin and polymer network enhances the mechanical property of hydrogel, so that the hydrogel has high strength, high toughness and good restorability. Furthermore, the addition of the polydopamine component makes hydrogel have good adhesion, and hydrogel can be adhered to surfaces of substrates with different chemical properties. The self-adhesive hydrogel with the anti-freezing / heat-resistant performance prepared with the method can be used as a wearable dressing to protect skin from cold injury or burn injury in an extremely cold or hot environment.

The invention relates to an integrated heat-supply and energy-saving system comprising a heat source, a heat-supply pipe network, a heat-supply control system, a pipe network balancing system and a waste heat recovering system, wherein the heat source is used for generating heat; the heat-supply control system is used for detecting indoor temperature to provide temperature parameters for weather compensation, monitoring the indoor temperature of users on line in real time and regulating the on / off of a relevant boiler, a circulating pump, an air conditioner, a ground source heat pump and a valve according to outdoor temperature and the indoor temperature of the users to control the heat-supply quantities of the heat users with different heat-supply properties, thereby realizing the automatic switching of anti-freezing running and heat supply; the pipe network balancing system is used for controlling each branch pipe to run by the set flow according to the branch pipe flows preset in one step, thereby improving the water pressure of the pipe network; and the waste heat recovering system is used for recovering energy for secondary application to reduce the heat loss of the heat-supply system. The integrated heat-supply and energy-saving system can automatically and intelligently control heat supply according to the heat-supply properties of the heat users, improve heat-supply quality, fully recycle waste heat at the tail end of the pipe network and carry out real-time on-line monitoring to the temperature of the pipe network.

The invention provides an air conditioner cooling unit and an anti-freezing control method thereof. The air-conditioner cooling unit comprises at least three temperature sensors. The anti-freezing control method comprises collecting the temperatures of the temperature sensors, and when all the temperature sensors break down, entering an anti-freezing mode; if at least one of the collected temperatures is lower than a first temperature threshold, entering the anti-freezing mode; when all the collected temperatures are higher than a second temperature threshold, exiting the anti-freezing mode. According to the air conditioner cooling unit, the water inlet, the water outlet and the inside of the shell tube of a shell-tube heat exchanger are provided with the temperature sensor, so that anti-freezing failure due to drifting or fault of certain temperature sensors can be avoided, effective anti-freezing effects on the shell-tube heat exchanger can be achieved, and the reliability of the shell-tube heat exchanger of the air conditioner cooling unit can be improved.

The invention relates to a nano interior wall coating; the composition by the weight percent is as follows: 35 percent to 45 percent of film-forming material, 28 percent to 42 percent of pigment and filler, 4 percent to 7 percent of assistant, 0.6 percent to 1.2 percent of nano powdery material, 1.0 percent to 2.0 percent of water-soluble nano silica sol, and 10 percent to 30 percent of deionized water. The film-forming material can be styrene-acrylic latex or acrylic latex; the pigment and filler is one or more than one type among rutile titanium dioxide powder, calcined kaolin, heavy calcium carbonate and super-fine aluminum silicate; the assistant comprises one or more than one type among dispersant, wetting agent, foam killer, preservative, thickener, anti-freezing agent, ph regulator and film-forming assistant. The coating of the invention can continuously release negative ions under the radiation of a fluorescent lamp, and can effectively degrade the dissociative TVOC and formaldehyde content in the air; the washing resistant times reaches 20000 to 50000 times, and the manual aging resistance reaches more than 1000 hours. In addition, the coating saves the consumption of nano powdery material and reduces the production cost.

The invention belongs to the industrial field of quick-frozen foods, and in particular relates to a quick-frozen dumpling and a preparation method thereof. The novel quick-frozen dumpling comprises a dumpling wrapper and dumpling stuffing, wherein the dumpling wrapper is made from flour, coarse cereals flour, vegetable protein powder, anti-freezing protein, modified starch, an enzyme preparation, vegetable polysaccharide and water; and the dumpling stuffing is made from meat, vegetables, a seasoner, modified starch, vegetable proteins and water. The quick-frozen dumpling is even and reasonable in nutrition collocation, abundant in nutrition, and delicious in taste. The novel quick-frozen dumpling is fresh in taste and good in color and luster under the freezing status, can notbe frozen to be cracked, and can not degrade the dumpling wrapper, the electric energy can be saved by more than 20% during producing, and the multiple effects for improving the high quality, saving the energy, and reducing the consumption are realized.

The invention discloses elastic anti-fouling outer wall paint with acid rain resistance. The outer wall paint comprises the following components in percentage by weight: 10 to 20 percent of water, 0.5 to 0.8 percent of acrylic ammonium salt dispersant, 20 to 26 percent of rutile type titanium white powder, 2 to 3 percent of kieselguhr, 8 to 15 percent of superfine barium sulfate, 1 to 2 percent of sericite powder, 40 to 50 percent of self-crosslinked elastic acrylic polymer latex, 3 to 5 percent of opaque covering polymer, 1 to 2 percent of anti-freezing agent, 1 to 2 percent of film-forming aid, 0.5 to 0.8 percent of mold-proof anti-algae agent, 1 to 3 percent of organic silicon waterproof agent and 0.5 to 1.5 percent of polyurethane associated thickener. The paint has the advantages of acid rain resistance, good anti-fouling performance, excellent elasticity, mold injury resistance, good storage stability and capability of repeatedly coating a paint film.

The invention discloses anti-freeze fluid. The compositions by weight percentage of the anti-freeze fluid are: 35 to 85 percent of glycol, 0.25 to 0.06 percent of sodium molybdate, 0.4 to 0.1 percent of sodium nitrate, 3.5 to 0.8 percent of potassium hydroxide, 1.2 to 0.2 percent of 85 percent phosphoric acid, 0.3 to 0.02 percent of metyl benzotriazole, 0.5 to 0.05 percent of benzotriazole, 3.5 to 0.8 percent of sebacic acid, 1.0 to 0.25 percent of undecanedioic acid, 1.0 to 0.2 percent of octanoic acid, 3.0 to 0.8 percent of sodium benzoate, 0.2 to 0.05 percent of hydrolytic-polymeric maleic anhydride, 0.003 to 0.01 percent of antifoaming agent, the balance being deionized water. The anti-freeze fluid is characterized by long effect and environmental protection, and can perform all-around multi-layer protection on an automobile cooling system.

A coating agent for rape seed is prepared from assistant, chemical and water through proportionally mixing and stirring. Said assistant includes filming agent, surfactant, anti-freezing agent, penetrant, etc. Said chemical includes insecticide, bactericide, plant growth regulator, trace element, fertilizer, etc. Its advantage is high effect to prevent and eliminate diseases and pests and increaseyield.

The invention relates to a preparation method of waterborne electromagnetic shielding coating. According to the formulation, the waterborne electromagnetic shielding coating is prepared from, by weight, 10.0-60.0 parts of water, 0.1-0.3 part of wetting agents, 0.4-0.8 part of dispersant, 0.1-0.3 part of defoamer, 0.7-1.3 parts of anti-freezing agents, 0.2-0.5 part of pH modifier, 20.0-60.0 parts of electromagnetic shielding additives, 0.5-2.0 parts of thickener, 25.0-40.0 parts of acrylic emulsion, 0.8-1.3 parts of coalescing agents, 0.2-0.4 part of preservative, 0.3-0.6 part of mould-proof anti-alga agents and 0.1-0.3 part of theological additives. The preparation method has the following advantages that the waterborne electromagnetic shielding coating prepared from graphene / nano ferrite, zinc oxide whiskers, nano silicon carbide, nanometal nickel powder and other materials has the advantages of being light, wide in frequency band, excellent in shielding performance, safe, environmentally friendly and the like, and the requirements of the electromagnetic shielding materials for impedance matching are met.

The invention discloses a compound plant anti-freezing agent and a preparation method thereof, aiming at the problems of single function and short protection period of the traditional plant anti-freezing agent. The compound plant anti-freezing agent comprises the following ingredients: 8-12% of a film-forming agent, 4-6% of saccharide, 10-16% of an anti-freezing reagent, 0.8-1.6% of an anti-freezing element, 4-6% of a micro element fertilizer, 0.2-0.4% of vitamin, 0-2% of a growth regulating agent, 1.2-2% of a surfactant and 60% of magnetized water. The compound plant anti-freezing agent is characterized in that the magnetized water is used for replacing common water to improve the activity of the anti-freezing agent. On one hand, one layer of protective film can be formed on the surface of the plant so as to perform the functions of resisting cold, preventing freezing and reducing transpiration water loss. On the other hand, the content of saccharide in plant cells can be improved, the activity of plasma membrane ATP (adenosine tTriphosphate) enzyme is increased, the phenomena of freezing in cells and cell freezing dehydration are avoided, and therefore the influence on the plant by freezing injury is effectively lowered.

A control method for an air conditioner which can perform low-temperature refrigeration is characterized in that an external fan is shut down to reduce heat exchange when that an indoor coil pipe is lower than a temperature value T<1> for a time duration t<1> is detected and a compressor operates continuously for more than t<y1>; the compressor is shut down and an internal fan operates according to a preset wind speed to perform anti-freezing protection when the indoor coil pipe is lower than a preset temperature value T<2> for a time duration t<2> and the compressor operates continuously for more than t<y2>; the whole set returns to normal operation when the indoor coil pipe is higher than a temperature value T<3>, and the external fan and the compressor are started, so that the air conditioner can refrigerate normally at a low temperature. The inventive method is simple and no other hardware is needed. The air conditioner can be started at a low temperature without basically changing indoor heat exchange effect and low-temperature refrigeration ability.