371results about How to "Fast defrosting" patented technology

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 a defrosting control method of a heat pump air conditioner unit. According to the outdoor environment temperature T4 of heat pump air conditioner operation, regional defrosting is conducted, and different defrosting control modes are conducted within regions of different temperatures. The outdoor environment temperature T4 during initial heat pump air conditioner operation is divided into N regions, different defrosting control methods are used in all regions, a controller is used for counting the air conditioner regional defrosting number when a machine is started up and heated, a special defrosting mode is conducted when the number reaches n, the entry condition of the special defrosting mode is the same as that of regional defrosting modes, and the exit condition is conducted in accordance with different control rules. By the aid of the method, the defrosting is conducted quickly, the indoor temperature fluctuation is small during defrosting, the heating amount is large and the heating can be conducted continuously. Simultaneously, the defects that the defrosting time is long and the defrosting is not complete due to hot gas bypass at the ultralow temperature are avoided. Users feel comfortable.

The invention discloses an air source heat pump type air conditioner and a defrosting method thereof. The air conditioner is outdoors connected with a first outdoor heat exchanger (4) and a second outdoor heat exchanger (5) in parallel, electromagnetic valves (6, 7, 8, 9) are respectively arranged on pipelines which connect the first outdoor heat exchanger (4) and the second outdoor heat exchanger (5) with a four-way valve (2), throttle devices (10, 11) are respectively arranged on the pipelines which are connected with an indoor heat exchanger (3), the electromagnetic valves (6, 7, 8, 9) are connected with a detection control system, and the throttle device (12) is connected between the first outdoor heat exchanger (4) and the second outdoor heat exchanger (5). When in need of defrosting, exhaust gas of a compressor is divided into two parts after passing through the four-way valve, one part enters the indoor machine for ensuring the indoor heat supply, the other part enters one of the outdoor heat exchangers for defrosting, condensate enters the other outdoor heat exchanger for evaporating after throttling, and refrigerant vapor returns to the compressor.

The invention relates to an air conditioner and a defrosting control method thereof. According to the defrosting control method, whether defrosting control needs to be conducted or not is judged by the way of judging the relation between outdoor environment temperature and outdoor coiled tube temperature, and the optimization time point for entering in the defrosting control can be accurately judged. After the defrosting control is conducted, the frequency of a compressor is changed, and after switching frequency is reached, a four-way valve is directly switched to conduct defrosting control. After defrosting is completed, the frequency of the compressor is changed, and after the switching frequency is reached, the four-way valve is directly switched so that defrosting operation can be achieved. By means of the air conditioner and the defrosting control method thereof, the precision for entering in and exiting out of defrosting can be guaranteed, meanwhile, due to the fact that halting can not occur to the compressor in the defrosting process, heating capacity attenuation caused by halting of the compressor is reduced, the defrosting cycle is shortened, and the heating comfort and the heating performance of the air conditioner are improved.

In a vehicle air conditioning apparatus where temperature of air blown toward a front seat side and temperature of air blown toward a rear seat side of the passenger compartment are independently controlled, a switching door for generally partitioning a downstream warm air passage of a heater core into first and second air passages is disposed at an air outlet side of the heater core. When heating capacity for the front seat side of the passenger compartment is necessary to be increased, the switching door is operated to a rear shutting position so that all air heated by the heater core can be introduced toward the front seat side through the first and second air passages of the warm air passage.

The invention discloses a governing system for constant temperature and constant humidity, comprising a compressor, a first heat exchanger, a throttling device, a second heat exchanger, a third heat exchanger, an indoor air flue, an outdoor air flue, a wetting device, a four-way reversing valve, a first proportional valve and a second proportional valve, wherein the compressor, the first heat exchanger, the throttling device and the second heat exchanger are connected in series to form a circulation loop; the third heat exchanger is connected with the second heat exchanger in parallel; the indoor air flue is provided with an indoor fan, the first heat exchanger and the heat exchanger; the outdoor air flue is provided with an outdoor fan and the third heat exchanger; the wetting path of the wetting device is communicated with the indoor air flue; the first port of the four-way reversing valve is connected with the air suction port of the compressor, the second port is connected with the first heat exchanger, the third port is connected with the exhaust port of the compressor, and the four port is connected with the node of the second heat exchanger and the third heat exchanger; and the first proportional valve and the second proportional valve are respectively installed on a refrigerant pipeline on which the second heat exchanger and the third heat exchanger are arranged. The invention can enlarge the temperature adjusting range when a complete machine operates and avoid the temperature adjusting dead zone. The invention also provides an integral constant temperature and humidity machine.

A quick chill and thaw system includes an air handler mounted in a fresh food compartment of a refrigerator and drawing air from a freezer compartment for rapid chilling of items inside a slide-out pan. The air handler produces convective airflow at temperatures within the pan at temperatures above and below a temperature of the fresh food compartment to achieve both chilling and thawing of items in the pan.

The invention is a kind of parallel heat pump temperature and humidity adjusting unit, which belongs to cooling, air conditioning and humidity eliminating technology field. The invention has a compressor, outdoor heat exchanger, the first and the second indoor heat exchanger and the restriction device, all of which are connected into a cooling circle through the cooling agent pipe, the outdoor heat exchanger and the second indoor exchanger are paralleled, the unit also includes a four-way valve. The invention can realize four kinds of different running mode through the four-way valve, and realizes quick frost eliminating without stop. The invention can satisfy the demands of large change of cold and hot load, and it can carries on micro adjustment through the on / off of the two electromagnetism valves on the two paralleled heat exchanger branches and adjusting the wind quantity and the water quantity in outdoor heat exchanger. The invention upgrades the utilization ratio of the device.

The invention discloses an air conditioner system and a control method thereof. The air conditioner system comprises an outdoor unit and one or more indoor units connected in parallel; the outdoor unit comprises a compressor, a gas-liquid separator, an oil separator, a four-way valve, an outdoor heat exchanger, an outdoor throttling element and a first cutoff valve; each indoor unit comprises an indoor heat exchanger; the first cutoff valve and the outdoor throttling element are connected in parallel; the air conditioner system also comprises a heat storing heat exchanger provided with a heat absorption heat exchange pipe, a heat releasing heat exchange pipe, a regulation valve and a second cutoff valve; the heat absorption heat exchange pipe and the regulation valve are connected in series to form a serial connection pipeline which is connected with the indoor unit in parallel; the heat releasing heat exchange pipe and the second cutoff valve are connected in parallel and form a parallel connection pipeline which is serially connected onto the pipeline between the gas-liquid separator and the four-way valve. The heat storing heat exchanger of the air conditioner system is flexible in arrangement, fast in defrosting speed, high in comfort level and capable of effectively avoiding the liquid slugging condition during the defrosting operation.

The invention provides a non-intermittent phase-change heat storage defrosting system, which relates to an energy storage defrosting system. The defrosting system aims at solving the problems that an air source hot pump defrosting method has the poor stability and reliability of machine units and the rooms become less comfortable after heat supply is stopped. The defrosting system of the invention is characterized in that an indoor machine is connected with a first pipeline and a second pipeline; an outdoor machine is connected with a second pipeline and a third pipeline; the third pipeline is respectively connected with the indoor pipeline and the outdoor pipeline; a fourth pipeline and a fifth pipeline are respectively connected with the fist pipeline and the third pipeline; a compressor is connected with a gas-liquid separator; a four-way directional valve is respectively connected with the first and the fifth pipelines, the gas-liquid separator and the compressor; the phase-change heat storage device is connected with the fifth and the fourth pipelines through a sixth pipeline and a seventh pipeline; an eighth pipeline is respectively connected with the fifth and seventh pipelines; a first valve, a second valve, a third valve, a fourth valve, a fifth valve, a sixth valve, a seventh valve, an eighth valve and a ninth valve are respectively arranged on the fifth pipeline, the sixth pipeline, the seventh pipeline, the eighth pipeline, the first pipeline, the second pipeline, the third pipeline, the fourth pipeline and the first pipeline; a capillary pipe is arranged on the fourth pipeline. The defrosting system of the invention has good stability and reliability, high defrosting speed, and high comfort level of the room after the heat supply is stopped.

The invention provides an air conditioner and a self-cleaning method thereof, and belongs to the technical field of air conditioners. The air conditioner comprises a control unit, wherein the control unit comprises a processor and a memory, a program and a preset parameter table are stored in the memory, when the program is executed by the processor, the method can be used for realizing the following steps of acquiring the indoor environment humidity; acquiring time and compressor frequency data according to the indoor environment humidity and the preset parameter table; controlling a compressor to run in a dehumidification mode according to the acquired compressor frequency F1 and the time T1 so as to forming condensed water on the surface of an evaporator; adjusting the frequency of the compressor to operate a refrigerating mode at a frequency higher than F2 so as to enable the condensed water to be iced, reducing the frequency of the compressor to rotate in F2 for T2 duration when the running duration reaches the preset time so as to enable the condensed water continues to be frosted; and controlling the air conditioner to enter a heating mode to carry out defrosting. The method has the advantages of being good in cleaning effect and wide in application range.

The invention provides an air conditioning system. The air conditioning system comprises a compressor, a four-way reversing valve, an outdoor heat exchanger, a flash evaporator and an indoor heat exchanger, wherein the compressor, the four-way reversing valve, the outdoor heat exchanger, the flash evaporator and the indoor heat exchanger are sequentially communicated. The first port of the flash evaporator is communicated with the first port of the outdoor heat exchanger, the second port of the flash evaporator is communicated with the gas supplement port of the compressor, and a gas supplement valve is arranged between the second port of the flash evaporator and the gas supplement port of the compressor. The third port of the flash evaporator is communicated with the first port of the indoor heat exchanger. The compressor is provided with a first gas suction port and a second gas suction port. The first gas suction port and the second gas suction port are communicated with the four-way reversing valve, and a gas suction valve is arranged between the first gas suction port and the four-way reversing valve. According to the air conditioning system, the double-cylinder capacity-variable technology and the double-stage compression, gas supplement and enthalpy increase technology are adopted, switching of the single-cylinder work mode and the double-cylinder work mode is achieved through opening and closing of the gas suction valve, and control over the gas supplement amount is achieved through opening and closing of the gas supplement valve. In the process of low-frequency and small-load single-cylinder operation, the energy efficiency is improved. In the process of high-frequency and large-load double-cylinder operation, the ability is improved.

The invention relates to a stepped refrigerating system for recovering oil gas, which comprises a primary refrigerating system, a secondary refrigerating system and a tertiary refrigerating system, wherein the primary refrigerating system is connected with the secondary refrigerating system connected with the tertiary refrigerating system. The invention has the benefits that a refrigerant in a hot steam manner is directly used for performing the phase change defrosting (hot freon defrosting), and the energy efficiency ratio is high. Since the hot freon defrosting is carried out in a heat exchanger, so that the heat transfer speed and the defrosting speed are high, the defrosting time of a primary oil gas condenser and a secondary oil gas condenser is within 15 minutes, and the defrosting time of a tertiary oil gas condenser can also be within 30 minutes. The defrosting time is saved greatly.

The invention discloses a defrosting method of an air source heat pump water heater. The defrosting method is characterized by comprising the following steps: the heat transfer temperature difference and the heat transfer temperature difference change speed are calculated through measuring the environment temperature and the temperature and time of an evaporator coil; the environment temperature, the opening time, the heat transfer temperature difference and the heat transfer temperature difference change speed are compared with defrosting condition set values; when four defrosting conditions are all satisfied, the defrosting signal is sent to realize defrosting through normally closed and normally open contacts of a defrosting relay, start and stop of a fan and a compressor of a control system and opening and closing of a four-way valve or a defrosting bypass electromagnetic valve or a defrosting hot water electromagnetic valve; the defrosting time and the temperature of the coil are compared with defrosting end signal set values; the defrosting end signal is sent; the defrosting end procedure is actuated; and the system recovers normal operation. The defrosting method comprises four-way valve reverse heat pump circulation, or bypass hot air defrosting, or hot water defrosting, or compound defrosting. The defrosting method is accurate in defrosting judgment, clear in logic, cheap in probe, easy for measuring signals and fast and thorough in defrosting, saves the energy, and is suitable for defrosting of all air source heat pump water heaters for sucking air energy to produce hot water.

The invention provides a defrosting control method for the air conditioner. The defrosting control method for the air conditioner comprises a frequency reducing step: reducing the running frequency of a compressor of the air conditioner when the air conditioner is in a heating mode if the condition that defrosting is needed is detected; a detection step: performing real-time detection on a current waveform state when the compressor runs; a frequency determining step: determining target frequency when the compressor quits low-frequency torque compensation according to the current waveform state; a defrosting step: switching the heating mode into a defrosting mode when the running frequency of the compressor is equal to the target frequency, and boosting the running frequency of the compressor so as to start defrosting. Correspondingly, the invention also provides a defrosting control system of the air conditioner and the air conditioner. Through the technical scheme adopted by the invention, the compressor may not be stopped during defrosting, and the heating effect is improved, so that the reliability of the air conditioner is improved, and the user experience is promoted.

The invention aims at providing an air conditioner which is mainly used for solving the problems of poor heat dissipation effect of an electrical appliance box and long defrosting time of an existing air conditioner. The air conditioner is added with a second heat exchanger system on the basis of an original heat exchange system, and further provided with a coolant branch to directly lead a first coolant flowing through a pipeline between an outdoor heat exchanger and an indoor heat exchanger in an air suction port of a first compressor; heat emitted by heating components in the air conditioner is absorbed through the second heat exchanger system and the absorbed heat is transferred to the first coolant in the coolant branch; in such a manner, a suction vapor superheat degree and a mass flow of the first compressor are improved while the heat dissipation problem is well solved, and further, the reliability of the air conditioner is improved and defrosting is accelerated; as a result, the comfort of use for users is improved. Meanwhile, the invention provides a control method of the air conditioner.

The invention discloses a multi-connected unit phase change energy storage hot liquid defrosting system and relates to the hot liquid defrosting system. The hot liquid defrosting system is designed against the problems that the defrosting system needs to absorb heat from a heating room during defrosting, thereby leading the room temperature to drop intensely; a four-way reversing valve carries out frequent reversion during the defrosting process, thereby affecting the service life; the defrosting speed is slow and the energy consumption is great. The four-way reversing valve is respectively communicated with a first main path and a third main path, the third main path is communicated with a gas-liquid separator, the gas-liquid separator is communicated with a compressor, the first main path is respectively communicated with a first branch pipeline and a second branch pipeline, an outdoor electronic expansion valve is connected with a second electromagnetic valve in parallel, a fourth electromagnetic valve and a subcooler are connected with a third electromagnetic valve and a phase change heat storage device in parallel, the subcooler is communicated with a fourth main path, the fourth main path is communicated with the gas-liquid separator, the first branch pipeline and the second branch pipeline are communicated with a second main path, a liquid storage device is arranged on the second main path, and the second main path is communicated with an indoor unit. The hot liquid defrosting system is used for multi-connected unit defrosting.

The invention discloses an air conditioner control method. The method includes the steps that when the air conditioner is in a self-cleaning mode, the air conditioner is controlled to conduct refrigerating running, and the air conditioner conducts condensation and frosting in sequence; the air conditioner is controlled to begin to conduct heating, and the rotating speed of a draught fan of a heatexchanger is controlled to be smaller than or equal to the preset value; the temperature of a coiler of the heat exchanger is obtained; and if the temperature of the coiler is larger than or equal tothe preset temperature, the draught fan is controlled to run with the increased rotating speed. The invention further discloses an air conditioner control device, the air conditioner and the readablestorage medium. The running reliability of a compressor is ensured while the cleaning effect is improved.

The invention discloses a self-cleaning control method of an outdoor heat exchanger of a variable-frequency air conditioner and the air conditioner. The method comprises the following steps that (1),the current outdoor environment temperature T-out is detected, moreover, whether the current outdoor environment temperature meets the condition of entering the self-cleaning control of the outdoor heat exchanger or not is judged, if yes, the step (2) is executed, otherwise, the self-cleaning control of the outdoor heat exchanger is not executed; (2), the outdoor heat exchanger is controlled for frosting; (3), frost formed by the outdoor heat exchanger is melted, and self-cleaning control is completed. According to the self-cleaning control method of the outdoor heat exchanger of the variable-frequency air conditioner, a large amount of low-density frost is formed quickly in a short time through the outdoor heat exchanger, then the frost is quickly melted, and then dust attached to the outdoor heat exchanger is washed away.

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 present invention relates to defrosting device of air heat exchanger. During defrosting, the special defrosting fan is controlled via time, temperature or pressure to blow in the opposite direction to normal direction, so that air is forced to flow from the no-frost side to the frosted side in the air heat exchanger and heated air is blown to the frost layer for thawing in convection, heat conducting and radiation modes.

An electrically powered windshield wiper fluid heater having a housing with an inlet and an outlet. A piston is movably mounted in the housing between a retracted and an extended position and the piston forms a thin annular passageway between the housing and the piston. During fluid flow from the inlet, through the annular chamber and to the outlet, the differential pressure moves the piston to its extended position thus closing a switch which powers a heating element disposed around the housing.

The invention discloses an air conditioner system comprising a compressor, a four-way valve, an outdoor heat exchanger, a first throttling part, an indoor heat exchanger, a first switch block, a three-way valve, a second throttling part and a control device. The first switch block is connected between an exhaust port of the compressor and an inlet of the outdoor heat exchanger during heating; the three-way valve is connected between the four-way valve and an air return port of the compressor; the second throttling part is connected between a port of the three-way valve and the air return port of the compressor. The control device firstly controls the first switch block to be turned on to perform bypass defrosting on the air conditioner when defrosting is needed, and controls the three-way valve to reverse so as to enable the second throttling valve to prolong staying time of refrigerant in the outdoor heat exchanger when bypass defrosting is not clean. The invention further discloses a defrosting control method of the air conditioner system. By the system and the method, defrosting time is shortened, and large indoor temperature fluctuation caused by reversing and defrosting of the four-way valve in the prior art is avoided.

The invention discloses an air conditioning system and a defrosting control method. The method includes the steps that in the heating process, when it is detected that the temperature of an outdoor heat exchanger is lower than a preset defrosting threshold value, a first electromagnetic valve and a third electromagnetic valve are controlled to be opened, a second electromagnetic valve is controlled to be closed, and a heating defrosting mode is started; after refrigerants passing through the outdoor heat exchanger and an indoor heat exchanger enter a heat accumulator in sequence to absorb heat, the refrigerants enter a compressor and then are compressed and discharged, and the discharged refrigerants enter the indoor heat exchanger for heating and enter the outdoor heat exchanger for defrosting correspondingly through a four-way reversing valve; and in the heating defrosting process, the work frequency of the compressor, the fan rotating speed of the outdoor heat exchanger, the fan rotating speed of the indoor heat exchanger and the opening degree of a throttling device are regulated and controlled. Heat, which dissipates into the air originally, of the compressor is stored in the heat accumulator, and the heat of the heat accumulator can be used for defrosting and also heating a room. The defrosting speed can be increased and the defrosting time can be shortened due to the fact that a storage heat source supply extra heat for defrosting. Meanwhile, part of the stored heat is used for continuous indoor heating, so that temperature fluctuation is reduced.

The invention provides a refrigerator and a defrosting control method thereof. The method adjusts voltage applied to an electromagnetic defrosting device according to the surface temperature of an evaporator. When the surface temperature of the evaporator is increased by a certain temperature value at each time, the voltage applied to the electromagnetic defrosting device is reduced, so that the power of the electromagnetic defrosting device is reduced. In the defrosting control method, when the surface of the evaporator is thicker in accumulated frost and lower in temperature, the electromagnetic defrosting device is operated with high power, so that the defrosting efficiency is improved; and when the surface of the evaporator is few in accumulated frost and higher in temperature, the electromagnetic defrosting device is operated with low power, so that quicker surface temperature rise of the evaporator is prevented. The method determines the operation power of the electromagnetic defrosting device according to specific defrosting conditions of the evaporator, guarantees normal and stable surface temperature rise of the evaporator, improves the defrosting efficiency, and optimizesthe working process of the electromagnetic defrosting device.

The invention discloses an indoor environment control unit and a building environment control system. The indoor environment control unit comprises an air inflow channel, an exhaust channel, a heat exchange device and a first air return control valve. The air inflow channel comprises a first air inlet communicated with the outside and a first air outlet communicated with the inside. The exhaust channel comprises a second air inlet communicated with the inside and a second air outlet communicated with the outside. The heat exchange device comprises a heat exchange air inflow channel located in the air inflow channel and a heat exchange exhaust channel located in the exhaust channel, the heat exchange air inflow channel is provided with a heat exchange inflow air outlet and a heat exchange inflow air inlet control valve, and the heat exchange exhaust channel is provided with a heat exchange exhaust air outlet and an exhaust air inlet control valve. The first air return control valve is used for making the exhaust channel and the air inflow channel communicated, and making air flow into the heat exchange air inflow channel from the exhaust channel through the heat exchange inflow air inlet control valve when the heat exchange inflow air inlet control valve is switched on. The indoor environment control unit and the building environment control system can adapt to low-temperature environments, and the frosting risk of the unit can be effectively reduced.

The invention discloses an air conditioning system with a defroster and a central air conditioning hot water system with the air conditioning system. The air conditioning system at least comprises a refrigeration and heating loop and a regenerator, wherein the refrigeration and heating loop is at least composed of a compressor, a four-way valve, an outdoor heat exchanger, an expansion valve and indoor heat exchangers which are connected through pipelines; the regenerator is internally provided with two groups of heat exchangers which can output heat, and the heat exchangers are respectively connected with an air-conditioning system pipeline through the pipelines; the regenerator is also internally provided with a third heat exchanger used for storing heat for the regenerator, and a connecting pipeline of each heat exchanger is connected in series with a control valve; a circulating pipeline arranged between the indoor heat exchangers and the expansion valve is connected in series with a control valve III which is arranged between inlet access points of the two heat exchangers; waste heat of a compressor is utilized to store heat for the regenerator, when the outdoor heat exchanger generates frost deposit, the open and close of the electromagnetic valve are controlled, a refrigerant flows across the regenerator and simultaneously absorbs heat in the regenerator, and the heat is utilized to defrost; the utilization ratio of an energy source is improved; and the loss of the air conditioning system is reduced.

The invention discloses a defrosting control method for a heat pump system. The method comprises the steps of detecting whether the heat pump system meets defrosting entry conditions in real time; determining whether defrosting of the last defrosting period is quit because the defrosting continuous running time is larger than t1 time when the heat pump system meets the defrosting entry conditions; entering four-way valve reversing defrosting when the defrosting of the last defrosting period is quit because the defrosting continuous running time is larger than t1 time, and quitting defrosting when four-way valve reversing defrosting quitting conditions are met to enter bypass defrosting, quitting defrosting when bypass defrosting quitting conditions are met to enter a normal heating mode. The invention further discloses a defrosting control device for the heat pump system. By means of the method and the device, rapid defrosting and clean defrosting can be achieved, and the indoor temperature fluctuation is small during defrosting.

The invention relates to a photoelectric sensing hot gas bypass defrosting refrigerator and a working method. A photoelectric sensor, a revaporizer, a bypass pipeline and a corresponding control system are added; the photoelectric sensor is adopted to replace the traditional defrosting control system; the thickness of a frost layer is taken as the criterion of defrosting; the method of hot gas bypass is adopted for defrosting, which causes refrigerators to thoroughly defrost. The defrosting refrigerator of the invention has simple structure, high defrosting speed and small temperature fluctuation of the refrigerator. The invention has obvious advantages on the following aspects of keeping the quality of frozen and chilled matters, saving refrigerator operation cost, prolonging service lifeand being conveniently used and the like, thus being the development tendency of the indirect cooling refrigerators in future.

The invention relates to multi-on-line variable-frequency air conditioners and provides a defrosting control method for the multi-on-line variable-frequency air conditioners in order to solve the problem that system performance is affected as a system cannot be defrosted normally. The method comprises the steps that firstly, the system detects the temperature of an outdoor environment and the temperature of heat exchangers of all outdoor units and figures out the temperature difference of the outdoor units, and meanwhile the system detects the continuous operation time of compressors of all the outdoor units; secondly, the system judges whether the continuous operation time of the compressors of the outdoor units is greater than or equal to the set operation time of the compressors and judges whether the temperature difference of the outdoor units is within a frosting temperature difference area or not at the same time; if yes, the system issues a defrosting application to a host; if not, the operation is repeated; finally, after receiving the defrosting application of any outdoor unit, the host judges whether to allow defrosting or not according to the current operation condition of the system; if yes, the host issues defrosting commands to all the outdoor units; if not, the operation is repeated; after receiving the defrosting commands, the outdoor units operate according to an automatic defrosting program and perform defrosting. The defrosting control method is suitable for the multi-on-line variable-frequency air conditioners.