502results about How to "Improve defrosting efficiency" patented technology

The invention discloses a method for air conditioner defrosting, which comprises the following steps, first, a pipeline is added between an air discharge pipe of a compressor and an air inlet pipe of a condensator in advance, and a magnetic valve is arranged on the pipeline, second, the temperature of a coil pipe of the condensator and temperature of outdoor environment are detected, third, a defrosting operation is judged to be operated or not according to the temperature of the coil pipe of the condensator and the outdoor environment, if the defrosting operation is needed, the fourth step is executed, otherwise the second step is executed, fourth, the magnetic valve is controlled to open, the frequency of the compressor is controlled to reduce to a first predetermined value, a four-way change-over valve is controlled to change into a refrigerating operation, fifth, the compressor is controlled to make an indoor set convert up to a second predetermined value according to the first predetermined speed, sixth, the temperature of the condensator is judged to detect whether the temperature is satisfied for a condition of the defrosting withdrawal, if satisfied, the seventh step is operated, otherwise, the fifth step is operated, seventh, the magnetic valve is closed, the compressor is controlled to convert down to a third predetermined value according to the second predetermined speed, and the four-way change-over valve is controlled to change to a heat-producing operation. The invention provides a method for air conditioner defrosting, which solves the problem that the period of defrosting for an air conditioner is longer, and defrosting effect of the air conditioner is influenced.

The invention discloses an air conditioner indoor / outdoor unit cleaning method. The method comprises the steps of: controlling a heat exchanger to be cleaned to enter a self-cleaning mode; adjusting the operation frequency of an air conditioner, the openness of a throttling device and the rotating speed of a fan corresponding to the heat exchanger to be cleaned, and controlling the evaporation temperature of the heat exchanger to be cleaned to keep in a preset range to condense the surface of the heat exchanger to be cleaned; condensing the heat exchanger to be cleaned by t1 time; detecting if the high / low pressure difference of the air conditioner reaches preset conditions; controlling a four-way valve to change the direction to perform the defrosting switching of indoor and outdoor heat exchangers when the high / low pressure difference of the air conditioner reaches the preset conditions; and adjusting air conditioner operation parameters when the high / low pressure difference of the air conditioner dose not reach the preset conditions, and then, controlling the four-way valve to change the direction to perform the defrosting switching of the indoor and outdoor heat exchangers when the high / low pressure difference of the air conditioner reaches the preset conditions. As the direction change of the four-way valve can be controlled through detecting if the high / low pressure difference of the air conditioner reaches the preset conditions, the higher shock on the compressor caused by excessive high / low pressure difference of the air conditioner can be prevented.

The invention discloses a heat pump system and a defrosting control method of the heat pump system. The heat pump system comprises a compressor, a four-way valve, an outdoor heat exchanger, an indoor heat exchanger and a heating device. The outdoor heat exchanger is a microchannel heat exchanger. When the system conducts defrosting, at least one flat pipe in the microchannel heat exchanger can be heated through the heating device. According to the heat pump system, defrosting is uniform, the defrosting efficiency can be improved, the system still can heat a room in the defrosting process, the indoor side temperature change range in the defrosting process is lowered, and the system comfort and defrosting efficiency are improved.

The invention discloses an air-conditioner internal and external unit cleaning method. The method comprises the steps that an indoor heat exchanger is controlled to enter a frosting mode; operation frequency of an air-conditioner, the opening degree of a throttling device and the rotating speed of an indoor fan are adjusted to enable evaporating temperature of the indoor heat exchanger to be kept within the preset range and the surface of the indoor heat exchanger to be frosted; frosting of the indoor heat exchanger lasts for time t1, later, frequency of a compressor is reduced, a four-way valve is controlled to be reversed, an outdoor heat exchanger enters a frosting mode, and meanwhile, the indoor heat exchanger is defrosted; the operation frequency of the air-conditioner, the opening degree of the throttling device and the rotating speed of an outdoor fan are adjusted, the evaporation temperature of the outdoor heat exchanger is kept within the preset range, and the surface of the outdoor heat exchanger is frosted; frosting of the outdoor heat exchanger lasts for time t2, the compressor is controlled to be shut down, and the indoor fan and the outdoor fan are kept starting until cleaning is completed. According to the air-conditioner internal and external unit cleaning method, the problem that in the prior art, the surface of the heat exchanger is cleaned through condensate water, and the effect is poor can be solved.

The invention provides a defrosting control method for an air conditioner. The air conditioner comprises a compressor, a four-way valve, an indoor heat exchanger, a first throttling device, outdoor heat exchangers, a refrigerant pipeline, a second throttling device, a first two-way valve and a second two-way valve. When defrosting begins, the second two-way valve is closed, and the first two-way valve is opened, a refrigerant sprayed by the compressor is divided into two branches at the second connecting point of the first two-way valve, wherein the main branch comprises the large part of refrigerant which flows to the first part heat exchanger of the outdoor heat exchangers to be used for defrosting, flows to the second part heat exchanger through the second throttling device to absorb heat and finally flows through the four-way valve to return into the compressor; the auxiliary branch comprises the other small part of refrigerant which flows through the indoor heat exchanger to exchange heat and flows through the first throttling device to join the main branch. In the defrosting process, the small part of the refrigerant flows to the indoor heat exchanger, an indoor unit has certain heat and does not have cold radiation, the problem that the indoor unit releases the refrigerating capacity to an indoor unit in the defrosting process of the air conditioner is solved, and the comfortable feeling of a user is improved.

The invention discloses an air-conditioner defroster. The defroster comprises a compressor, a four-way valve, an evaporator and a condenser. The defroster also comprises a first pipeline for connecting a liquid inlet of the evaporator with a liquid outlet of the condenser; a second pipeline for connecting an air return inlet of the evaporator with a first port of the four-way valve; a third pipeline for connecting an air inlet of the condenser with a second port of the four-way valve; a fourth pipeline for connecting an air outlet of the compressor with a third port of the four-way valve; a fifth pipeline for connecting a suction inlet of the compressor with a fourth port of the four-way valve; a bypass pipeline with one end communicated with the first pipeline and the other end communicated with the fourth pipeline; a bypass control valve arranged on the bypass pipeline for starting / closing the bypass pipeline; a throttle valve arranged on the first pipeline for regulating the flow of refrigerant in the first pipeline through adjusting the openness of the throttle valve. The invention combines the advantages of heat pump defrosting and hot gas bypass defrosting and can achieve the most effective defrosting.

In a cooling system having a compressor for supplying refrigerant under pressure, a condenser for condensing the refrigerant supplied from the compressor, a liquid receiver arranged to temporarily store the condensed refrigerant supplied from the condenser, an expansion valve for expanding the refrigerant supplied from the liquid receiver, and an evaporator arranged to effect evaporation of the expanded refrigerant for cooling the surrounding thereof, a bypass conduit is arranged to bypass the liquid receiver and expansion valve, and an electrically operated flow passage changeover valve is provided to selectively connect a supply passage of refrigerant to the liquid receiver and expansion valve and to the bypass conduit so that the supply passage of refrigerant is connected to the liquid receiver and expansion valve during operation at a cooling mode and is connected to the bypass conduit during operation at a defrost mode.

The invention relates to a method and device for controlling an air conditioner to be defrosted. The method comprises the following steps: a defrosting time interval is obtained according to the mapping relation between the outdoor and indoor environmental temperatures and the defrosting time interval; the air conditioner is controlled to be defrosted when the running time of the air conditioner between the end of last defrosting to the present is greater than or equal to the defrosting time interval obtained. Since the defrosting time interval is definite, the start time for defrosting is relatively accurate, and the defrosting efficiency is high.

The invention provides an air conditioner defrosting circulation system comprising a compressor. A compressor exhaust pipe is connected with a four-way valve which is connected with an outdoor heat exchanger, an indoor heat exchanger and a gas-liquid separator, the gas-liquid separator is connected with a compressor intake pipe, a heat storage water tank is arranged on the compressor exhaust pipe, and a water spray port of the heat storage water tank is formed in the outdoor heat exchanger and matched with a return pipe of a water storage tank. The four-way valve is not switched, but the heat-preservation heat storage water tank is arranged on the compressor exhaust pipe to collect waste heat during circulation and fully utilize the waste heat, an outdoor unit is defrosted by a hot water spraying mode, normal heating of an indoor unit is guaranteed in the whole defrosting process, heating efficiency is improved effectively, and service life of the system is prolonged.

The invention relates to an air conditioning device and a control method thereof. The air conditioning device comprises a compressor, a four-way valve, an indoor heat exchanger, a sleeve pipe heat exchanger, an expansion valve and an outdoor heat exchanger. The control method comprises the steps that when the air conditioning device carries out heating operation till the outdoor heat exchanger needs to be defrosted, whether the outdoor environment temperature is within the range of a preset temperature interval or not is judged, and if yes, a down-flow defrosting mode is started; in the down-flow defrosting mode, the state of the four-way valve is kept unchanged, the expansion valve is promoted to be totally opened, whether the temperature of a coil pipe of the indoor heat exchanger is larger than or equal to a first preset temperature or not is judged, and if yes, an indoor fan is started; and if no, the indoor fan is stopped, the coil pipe of the indoor heat exchanger is heated, andafter the temperature of the coil pipe of the indoor heat exchanger reaches or exceeds the first preset temperature, the indoor fan is started. The technical problem that in the existing defrosting process, the indoor temperature fluctuation is large, and consequently comfort is poor is avoided; the defrosting time is shortened; noise is reduced; and operation stability is improved.

The invention discloses an evaporator and a defrosting device thereof. The defrosting device of the evaporator comprises an electromagnetic heating module and a metal heating unit matched with the electromagnetic heating module. Through arrangement of the electromagnetic heating module and the metal heating unit matched with the electromagnetic heating module, by virtue of an electromagnetic induction principle, when the electromagnetic heating module works, an alternating magnetic field is generated around the electromagnetic heating module, and when magnetic lines of the alternating magnetic field pass through the metal heating unit, large eddy current is generated inside the metal heating unit to enable the metal heating unit to generate heat so as to heat and defrost; the metal heating unit can be set into a proper form in a matching way according to the size and the shape of the evaporator, so that overall heating of the evaporator is achieved, the defrosting efficiency is improved and the energy consumption is reduced.

The invention provides a base plate structure for an outdoor unit of an air conditioner, the outdoor unit of the air conditioner, the air conditioner and a defrosting control method for the air conditioner. The base plate structure for the outdoor unit of the air conditioner comprises an outdoor unit base plate, a base plate electric heating element and a drainage part, wherein a compressor fixing support is arranged on the outdoor unit base plate, and a condenser is installed on the outdoor unit base plate; the base plate electric heating element is arranged at the bottom of the condenser and located above the outdoor unit base plate; and the drainage part is arranged on the outdoor unit base plate and comprises at least one main drainage port, and the main drainage port is located below the base plate electric heating element. By adopting the base plate structure, when the air conditioner is heated for defrosting at a lower outdoor temperature, frost on the condenser and the outdoor unit base plate can be quickly and thoroughly thawed, and the thawed water quickly and smoothly flows out of the main drainage port, so the frost is thawed cleanly and thoroughly, the temperature of an indoor air port is improved, a good heating effect is guaranteed, and the market competitiveness of the product is improved.

The invention provides a hot air defrosting system for a refrigerator and a control method of the hot air defrosting system. The system comprises a defrosting branch. The defrosting branch is connected between an outlet of a compressor and an inlet of a freezing evaporator in parallel. The system further comprises a controller, a freezing chamber wall temperature sensor connected with the controller and arranged on the surface of the freezing chamber evaporator, a compressor suction temperature sensor arranged on the surface of a compressor suction pipeline, and a second two-position three-way valve arranged on an outlet of the freezing chamber evaporator. A first two-position three-way valve is also connected with the controller. The system further comprises a second capillary pipe, and the second capillary pipe is independently connected to the position behind the freezing evaporator and in front of a refrigerating evaporator in parallel through the second two-position three-way valve, or connected with the refrigerating evaporator in series and then connected to the position behind the freezing evaporator and in front of a liquid storage device in parallel through the second two-position three-way valve. The invention further provides the control method. By the adoption of the hot air defrosting system and the control method, the refrigerating evaporator of the refrigerator is complete in defrosting operation, defrosting energy consumption is low, defrosting time is short, and the temperature rise of a freezing room is small.

The invention discloses a multi-zone frosting map-based defrosting control method of an air source heat pump and belongs to the technical field of defrosting. The control method is used for realizing efficient defrosting on the basis of multi-zone frosting maps by monitoring temperatures, humidity and time for air source heat pump units such as air source heat pump hot and cold water units, heat pump type room air conditioners and the like. The technical scheme is as follows: firstly, frosting maps of multiple zones are developed and contain two lines, three zones and five regions, and frosting speeds of the air source heat pump under different environment conditions can be judged according to the frosting maps of the zones; then monitored running time of the air source heat pump in different frosting zones is converted into standard defrosting time, and when the accumulated value of the time is equal to the set optimal defrosting interval, an air source heat pump unit begins to defrost. With the adoption of the method, the defrosting moment can be accurately judged, false defrosting accidents can be avoided, and the defrosting efficiency is high; the method is not limited by regions and climates and is high in practicability.

The invention relates to the technical field of air conditioning equipment, in particular to an air conditioner capable of continuously heating and defrosting and a control method of the air conditioner. The air conditioner capable of continuously heating and defrosting comprises an outdoor heat exchanger, an indoor heat exchanger, a compressor, a throttling device and a four-way valve, wherein the four-way valve comprises a first valve port, a second valve port, a third valve port and a fourth valve port, the first valve port and the second valve port are respectively communicated with the air suction end and the air exhaust end of the compressor, and the third valve port is communicated with the indoor heat exchanger; the outdoor heat exchanger comprises at least two outdoor heat exchanger units which are arranged in parallel, one end of each outdoor heat exchanger unit is connected with a reversing device in series, and each reversing device selectively enables the outdoor heat exchanger units to be communicated with the third valve port or the fourth valve port. Through the structure, low influence on indoor temperature during heating and defrosting processes of the air conditioner is realized, and the using comfort degree of the air conditioner is increased.

The invention provides a defrosting control method for an air conditioner. The air conditioner comprises a compressor, a first four-way valve, an indoor heat exchanger, a throttling device, an outdoor heat exchanger, a refrigerant pipeline, a second four-way valve, an electromagnetic valve and a heat storage device. When the air conditioner is in heating operation, the first four-way valve and the second four-way valve are both converted into a heating mode, a heat storage mode for the heat storage device is controlled to be started and stopped by controlling the on-off state of the electromagnetic valve, and heat stored by the heat storage device is used for achieving a heat source provided when heating and defrosting are simultaneously conducted. When the air conditioner is in defrosting operation, the first four-way valve is kept in the heating mode, the second four-way valve is converted into a refrigerating mode, the electromagnetic valve is opened, refrigerant gas sprayed by the compressor is divided into two branches, the refrigerant gas exhausted by the compressor simultaneously flows to the indoor heat exchanger and the outdoor heat exchanger, in the defrosting process, refrigerant simultaneously flows to the indoor heat exchanger and the outdoor heat exchanger, certain heat exists on the indoor side, cold radiation is not generated, and user comfort is greatly improved.

The invention discloses a heat pump system and a defrosting control method thereof. The heat pump system comprises a compressor, a four-way valve, an outdoor heat exchanger, an indoor heat exchanger and a heating device. The outdoor heat exchanger is a micro-channel heat exchanger; and during system defrosting, the heating device can heat at least one header pipe of the micro-channel heat exchanger. According to the heat pump system, defrosting is even, the defrosting efficiency can be improved, the system can still heat the indoor space in the defrosting process, the temperature variation amplitude of the indoor side in the defrosting process is reduced, and the system comfort and the defrosting efficiency are improved.

The invention discloses a defrosting control method and device of an air conditioner. The method comprises the steps that a compressor of the air conditioner is controlled to be started to conduct heating operation; after the compressor operates for a first preset period of time, a flow rate effective value V0 of refrigerating fluid in an outdoor unit coil pipe, an indoor environment temperature effective value Tn0, an outdoor environment temperature effective value Tw0 and an effective value Tp0 of an indoor unit coil pipe are obtained; a first flow rate current value Vt of the refrigerating fluid in the outdoor unit coil pipe, an indoor environment temperature current value Tnt, an outdoor environment temperature current value Twt and a current temperature value Tpt of the indoor unit coil pipe are obtained; according to the V0, the Tn0, the Tw0, the Tp0 and the Vt, the Tnt, the Twt and the Tpt, whether the air conditioner meets a defrosting condition is determined; and if the air conditioner meets the defrosting condition, the air conditioner is controlled to be in a defrosting mode to conduct defrosting. By means of the method and the device, mistaken judgment of defrosting can be reduced, and defrosting efficiency is improved.

The invention discloses an air source heat pump unit adopting double evaporators to alternately perform defrosting and a defrosting method thereof. Two air-cooled evaporators in parallel connection are arranged in an air source heat pump system; when one air-cooled evaporator frosts and enters the defrosting mode, the evaporator requiring to be defrosted is switched into a subcooler through function switch of a four-way reversing valve and a throttle mechanism in the air source heat pump system, a frost layer on the surface of the evaporator requiring to be defrosted is molten and removed through a high-pressure high-temperature liquid refrigerant at an outlet of a condenser in the air source heat pump system, and the defrosting purpose is achieved; and the other air-cooled evaporator absorbs heat from the environment, and continuous heating is achieved. The air source heat pump unit has the advantage that the direction of the refrigerant does not change during the defrosting process, reliability is relatively high, heating is continuously carried out during the defrosting process, comfort during the utilization process is improved, energy consumption during the defrosting process of the heat pump unit almost can be neglected, and defrosting efficiency is greatly improved.

The invention discloses an air conditioner and a defrosting method thereof. The air conditioner comprises a heat exchange system and a control system, wherein the heat exchange system comprises a compressor, a four-way valve, a first indoor heat exchanger, a second indoor heat exchanger, a throttling device, a first outdoor heat exchanger and a second outdoor heat exchanger, wherein an indoor unit adapter of the four-way valve is connected with the inlet pipe of the first indoor heat exchanger and / or the inlet pipe of the second indoor heat exchanger, and an outdoor unit adapter of the four-way valve is connected with the outlet pipe of the first outdoor heat exchanger and / or the outlet pipe of the second outdoor heat exchanger; and the outlet pipe of the first indoor heat exchanger and the outlet pipe of the second indoor heat exchanger are connected with the inlet pipe of the first outdoor heat exchanger and / or the inlet pipe of the second outdoor heat exchanger through the throttling device, the outlet pipe of the first outdoor heat exchanger is connected with the inlet pipe of the second outdoor heat exchanger, and the outlet pipe of the second outdoor heat exchanger is connected with the inlet pipe of the first outdoor heat exchanger. By adoption of the air conditioner and the defrosting method thereof, the indoor comfort degree is guaranteed, and meanwhile, the defrosting efficiency of the air conditioner is improved.

The invention relates to the technical field of an air conditioner defrosting and provides an air conditioner outdoor unit defrosting method. When the refrigeration mode is selected to perform defrosting, firstly an indoor fan stops operating to enable residual heat of an indoor heat exchanger to completely act on a refrigerant recycling back; when the temperature of the indoor heat exchanger is reduced to be lower than the indoor temperature, the indoor fan is started, indoor heater air is utilized to conduct convective heating on the indoor heat exchanger, and the indoor fan stops operating to prevent somatosensory cold air enabling human to obviously feel cold from being produced till the temperature of the indoor heat exchanger is reduced to reach a cold air preventing temperature threshold. In the whole defrosting process, the residual heat of the indoor heat exchanger is fully utilized, the indoor air heat is further properly utilized, accordingly the defrosting time is overall shortened, the defrosting efficiency is improved, and the overall energy efficiency ratio of an air conditioner is also improved.

The invention provides a defrosting control method and device. The method includes the steps that whether the environment temperature is lower than the preset temperature threshold value or not is confirmed, and if the environment temperature is lower than the preset temperature threshold value, the defrosting temperature of a unit is obtained; whether the difference value between the environment temperature and the defrosting temperature is larger than the preset defrosting temperature difference or not is judged; and if the difference value is larger than the preset defrosting temperature, the unit is controlled to enter in the defrosting operation. The defrosting control method solves the problem that at present, whether the defrosting operation is executed or not is judged simply according to the defrosting temperature, and consequently the defrosting executing time is not accurate, and the defrosting efficiency is effectively improved.

The invention discloses a method for using thin-wall bamboo materials to prepare bamboo scrimbers. The method includes the steps that alkali is adopted for stewing thin-wall bamboo sheets, and then defibering, gum dipping, laying and hot pressing are carried out in sequence; NaOH is used for stewing the bamboo sheets, and the bamboo sheets are processed by lipase and then subjected to defibering,wherein by means of the procedures above, the defibering effect of bamboo bundles is obviously improved by 35% or above, bamboo green and tabasheer on the surfaces of the bamboo materials are effectively subjected to chemical erosion, the purpose of breaking wax layers and silicon layers is achieved, and the effect of improving gluing is achieved. A waste liquid generated after stewing is used fordiluting a glum liquid, and the problem of discharging the waste liquid is solved; by adopting a vacuum pressurizing dipping mode, even permeation of an adhesive in the bamboo materials is achieved,consumption of the adhesive is reduced, the production cost is reduced, efficient utilization of the thin-wall bamboo materials is achieved, and the environment is protected. The physical and chemicalstrength of the scrimbers are obviously improved, the horizontal shearing strength is improved by 25% or above, the thickness swelling rate of water absorption is reduced by 100% or above, the bending strength is improved by 20% or above, and the elasticity modulus is increased by 15% or above.

The invention provides a control method of an air cooling refrigerator. The method comprises the steps as follows: in a refrigeration process of the air cooling refrigerator, whether the air cooling refrigerator meets a defrosting condition is judged; if the air cooling refrigerator meets the defrosting condition, a compressor of the air cooling refrigerator is controlled to be shut down, and a refrigerating blower is continuously controlled to operate a first preset time and then be closed; and after the refrigerating blower closes a second preset time, the air cooling refrigerator is controlled to enter a defrosting mode for defrosting. According to the control method of the air cooling refrigerator, the defrosting efficiency is improved, the energy consumption is reduced, and food deterioration caused by larger fluctuations of temperatures in refrigerator compartments can be avoided. The invention further provides the air cooling refrigerator.

A vapor compression refrigeration and freezer system includes a compressor, a condenser, an expansion devise and an evaporator which includes an evaporator coil having an inlet and an outlet which coil is in heat exchange relation with an air medium along substantially the entire coil length. The inlet to the evaporator coil is in flow communication with an outlet of the expansion devise via an evaporator feedline. The expansion device can include a multifunctional valve that cooperates with the evaporator feedline to supply the evaporator coil inlet with a mixture of refrigerant vapor and liquid at a linear velocity and with relative amounts of vapor and liquid which are sufficient to provide efficient heat transfer along substantially the entire length of the coil, substantially reducing the build-up of frost on the evaporator coil and enabling the system to be operated without requiring a defrosting cycle over a substantially increased number of operating cycles compared to conventional refrigeration and freezer systems operating at the same cooling load and evaporating temperature conditions.

The invention provides a defrosting control method, which comprises the following steps: pre-judgment step: judging whether a unit meets a defrosting requirement or not, wherein the defrosting requirement includes: the unit continuously operates for preset time T1, outer unit tube temperature of the unit is less than a first preset value within preset time T2, water inlet temperature of the tail end of the unit is higher than a second preset value, and water outlet temperature of the tail end of the unit is higher than a third preset value; defrosting control step: If the operation status of the unit meets the defrosting requirement, indicating that the unit enters a defrosting operation status. The defrosting control method provided by the invention can be carried out rapidly and accurately, thus the defrosting efficiency of the unit is improved.

The invention provides a defrosting control method and system of a heat pump air-conditioning unit. The defrosting control method is used for defrosting multiple pipeline systems of the air-conditioning unit and comprises the following steps: whether pipeline systems meeting defrosting requirements exist is detected, if yes, the quantity of the pipeline systems meeting the defrosting requirements is detected; whether the percentage of the quantity of the pipeline systems meeting the defrosting requirements in the total quantity of the pipeline systems is larger than a preset percentage or not is determined; if yes, the pipeline systems meeting the defrosting requirements are sorted according to total run time of corresponding compressors; and a preset quantity of pipeline systems in the pipeline systems meeting the defrosting requirements are in a defrosting mode, and other pipeline systems are in a heating mode. According to the defrosting control method and system, in the defrosting process, part of the pipeline systems defrost, the other pipeline systems perform heating, so that heating continuity for users is guaranteed, the use comfort of the users is improved, the heating pipeline systems provide heat for the defrosting pipeline systems, and the defrosting efficiency is increased.

The invention provides an air conditioner and a control method and device thereof. The control method includes the steps that when the air conditioner is in heating running, the frosting amount of an outdoor unit heat exchanger of the air conditioner is acquired; whether the frosting amount is larger than a preset value or not is judged; when the frosting amount is larger than the preset value, the air conditioner is controlled to get into a defrosting mode. According to the control method of the air conditioner, whether defrosting is started or not is judged according to the frosting amount, generated when the air conditioner is in heating running, of the outdoor unit heat exchanger, and when the frosting amount exceeds a certain threshold value, the air conditioner is controlled to start defrosting; due to the fact that the frosting amount is directly used as a judgment basis, the accuracy of defrosting start judgment of the air conditioner is effectively improved, the problems that in the prior art, a defrosting start signal source of an air conditioner is fuzzy, and start of the defrosting mode cannot be precisely controlled are solved, and then the defrosting efficiency of the air conditioner during low-temperature heating is effectively improved.

The invention discloses a cascade CO2 heat pump capable of achieving defrosting through reversing of a four-way valve and a defrosting method of the cascade CO2 heat pump, and belongs to heating cycle technologies of heat pumps. A conventional CO2 heat pump system cannot achieve defrosting through reversing of the four-way valve. The cascade CO2 heat pump is characterized in that a mature four-way valve reversing defrosting technology of a conventional refrigerant system is fully utilized, when a system detects that an air source evaporator needs to be defrosted, a second compressor is stopped, the CO2 heating cycle is stopped, a four-way valve of the conventional refrigerant system is controlled, the conventional refrigerant system absorbs heat from a user hot water demand side, and the frost condensed on the surface of an air source heat exchanger is removed. According to the cascade CO2 heat pump and the defrosting method, the defrosting time of a cascade CO2 system can be remarkably shortened, the defrosting efficiency of the system is improved, and a technical scheme is provided for reliable operation of the heat pump system at an extremely low environmental temperature.