70 results about "Variable refrigerant flow" patented technology

The invention provides a control method and system of a variable refrigerant flow (VRF) air conditioner. The VRF air conditioner comprises an outdoor unit and a plurality of indoor units. An electronic expansion valve is mounted in each indoor unit. The control method includes: when an instruction for turning off all the indoor units of the VRF air conditioner is received, controlling the compressor of the outdoor unit to stop operation, and controlling an optional number of electronic expansion valves in all the indoor units to keep a preset openness; detecting the difference of high pressure and low pressure in the compressor, and / or recording the duration of operation stopping; when the detected pressure difference is smaller than or equal to a preset pressure value and / or the duration of operation stopping reaches preset duration, controlling the four-way valve in the outdoor unit to deenergize. By the control method, when all the indoor units of the VRF air conditioner are turned off, air flow impact noise can be avoided while air conditioner energy consumption can be lowered under the premise that the difference of the high pressure and the low pressure in the compressor is balanced.

The invention discloses a VRF (Variable Refrigerant Flow)air-conditioner fault handling method which comprises the following steps: an air-conditioner acquires fault information and determines the grade of the fault information; the fault information and the grade thereof are uploaded to a server, so that the server sends an emergency instruction of service in derated capacity back to the air-conditioner when determining that the fault information is in the preset first grade; the air-conditioner operates according to preset safety parameters when receiving the emergency instruction of service in derated capacity and enters a fault halt state after operating for a preset period of time. The VRF air-conditioner fault handling method facilitates the maintenance work of maintenance personnel and improves the service efficiency of a VRF air-conditioner.

The invention relates to the field of air conditioning, in particular to a variable refrigerant flow radiation air-conditioning system. The variable refrigerant flow radiation air-conditioning system comprises an indoor machine, an outdoor machine, a sub-water collector, a radiation tail end and a dew-point temperature controller; the indoor machine is connected with the outdoor machine in series; the radiation tail end is connected with the indoor machine through the sub-water collector; the dew-point temperature controller is connected with the sub-water collector and used for perceiving indoor temperature and humidity changes and preventing the phenomenon that condensation may occur on the radiation surface under the circumstance of wind system faults through the mode that a water circulation valve is cut off in advance. According to the variable refrigerant flow radiation air-conditioning system, heating and humidification can be performed in winter, refrigeration and dehumidification are performed in summer, meanwhile, new wind is fed to an indoor area after purification, and it is guaranteed that indoor air temperature and humidity and cleanliness reach a living optimal comfortable state. The variable refrigerant flow radiation air-conditioning system has the advantages that the installation is simple, the reliability is high, the indoor temperature, the humidity and the air cleanliness are adjusted uniformly and softly, and no noise, condensate water, secondary pollution and the strong blowing feeling exist. The equipment whole volume is small, the occupied space is small, the noise is low, and the appearance is beautiful.

A modular stand system is adjustable in the transverse direction and height and is adapted for HVAC system components that need to be elevated above a support surface. In certain embodiments, the modular stand systems herein are advantageously used to support HVAC variable refrigerant flow (VRF) units.

The invention provides a VRF (variable refrigerant flow) air conditioning system and a control method of the VRF air conditioning system. In the VRF air conditioning system, an outdoor machine comprises an outdoor controller, a coolant flow regulating valve, a drain pipe temperature sensor and an intake pipe temperature sensor, wherein the coolant flow regulating valve is used for regulating the flow of a coolant entering an indoor machine, and the drain pipe temperature sensor and the intake pipe temperature sensor are used for detecting the temperature of a drain pipe of a condenser and the temperature of an intake pipe of the condenser. The control method comprises the following steps of: receiving practical temperature data measured by the drain pipe temperature sensor and the intake pipe temperature sensor; determining an opening degree regulating value of the coolant flow regulating valve; and controlling the opening degree of the coolant flow regulating valve according to the opening degree regulating value. According to the VRF air conditioning system disclosed by the invention, the coolant flow regulating valve, the drain pipe temperature sensor and the intake pipe temperature sensor, all of which are originally arranged in the indoor machine, are transferred and are arranged in the outdoor machine so that an outdoor machine controller is used for directly carrying out signal communication with each temperature sensor and an intermediate loop of signal transmission of the indoor machine controller is reduced, thus a control process of the VRF air conditioning system is quicker and more convenient.

A system comprising a compressor coupled to a first coil through a first valve and a second coil through a second valve, wherein the first coil and the second coil are coupled to a third coil. The system further comprises a fan operable to blow ambient air across the first coil, a first expansion valve coupled to and positioned between the first coil and the third coil and a second expansion valve coupled to and positioned between the second coil and the third coil. The system comprises a controller operable to monitor a pressure of the refrigerant, operate the first expansion valve to reduce refrigerant flow into the first, and operate the second expansion valve to reduce refrigerant flow through the second coil.

The invention discloses a variable refrigerant flow system and a low-temperature control method thereof. The method comprises the following steps of obtaining the current operating mode of the variable refrigerant flow system; if the current operating mode of the variable refrigerant flow system is a pure refrigeration mode, obtaining the current outdoor environment temperature and judging whetherthe current outdoor environment temperature is smaller than or equal to the first preset temperature or not; and if the current outdoor environment temperature is smaller than or equal to the first preset temperature, obtaining the evaporation temperature of at least one indoor unit of multiple indoor units and the preset target evaporation temperature and controlling the opening degree of a throttling assembly according to the evaporation temperature of at least one indoor unit of multiple indoor units and the preset target evaporation temperature. By means of the low-temperature control method, during low-temperature refrigeration, the low pressure of a refrigeration indoor unit is prevented from being too low by controlling the opening degree of the throttling assembly arranged on a low-pressure air pipe of a throttling device, so that the refrigeration indoor unit is effectively prevented from freezing, the refrigeration indoor unit can conduct refrigeration continuously, and therefrigeration effect is ensured.

The invention relates to an oil returning control method for a direct current frequency conversion variable refrigerant flow air conditioner. The method comprises the following steps: (1) arranging anoil returning temperature sensor on an oil returning pipeline of a compressor; (2) setting system parameters; and (3) judging whether a system needs the oil returning, wherein the system enters an oil returning mode for operation if the system needs oil returning, and the oil returning is finished after the system enters the oil returning and operates for a period of time if the halt protection or frequency reduction protection of the system is not triggered in the oil returning process. The oil returning control method has the advantages that the oil returning of the system can be effectively ensured when the direct current frequency conversion variable refrigerant flow air conditioner continues to stably operate at high frequency under the mode of high temperature refrigeration, such that the condition that the compressor is burnt out due to oil lack can be effectively avoided, and the damage to the system can be effectively avoided.

The invention provides a variable refrigerant amount air conditioning system and a control method thereof. The air conditioning system comprises a refrigerant circulation loop which comprises a four-way reversing valve, an indoor heat exchanger, a throttle valve and an outdoor heat exchanger, the air conditioning system further comprises a refrigerant amount adjusting loop connected with the refrigerant circulation loop. The refrigerant amount adjusting loop comprises a liquid storage device with two ports, the first port of the liquid storage device is communicated with a pipeline between thefour-way reversing valve and the outdoor heat exchanger through a first pipeline, and the second port of the liquid storage device is communicated with a pipeline between the throttling valve and theindoor heat exchanger through a second pipeline. A first control valve and a second control valve which are connected with the same controller are correspondingly arranged on the first pipeline and the second pipeline; and a refrigerant is preset in the liquid storage device. According to the variable refrigerant amount air conditioning system and the control method thereof, the amount of refrigerant circulating in the air conditioning system can be controlled, the optimal refrigerant amount of operation of the air conditioning system is guaranteed, and therefore the heat exchange efficiencyis brought into play to the maximum extent.

The invention relates to a variable refrigerant flow system combined with air source heat pump hot water and a control method of the variable refrigerant flow system. According to the variable refrigerant flow system, condenser heat of a traditional VRF air conditioner in summer is recycled effectively for preparing domestic hot water, part of the obtained domestic hot water is used for domestic water, the other part of the obtained domestic hot water is used for reheating air supplied by an indoor air conditioner, and thus the influence of dew-point air supply of a multi-split air conditioner system on the indoor environment temperature and the human body comfort is eliminated; and in addition, after the VRF outdoor unit is frosted at the low temperature in winter, defrosting is conducted through an air source heat pump hot water system, and the defect of fluctuation, caused by reverse operation of the air conditioner system in winter, of the indoor environment temperature is overcome. The system also can meet the needs of users on the domestic hot water all year around. The users can switch the operation mode by the users according to the needs, the condenser heat is fully utilized, and the variable refrigerant flow system and the control method have the beneficial effects that control is flexible, selection is diversified, energy is saved during operation, the indoor environment temperature fluctuation is small, and the comfort is high.

The invention discloses a variable refrigerant volume system, which comprises an outdoor unit device, a shunting device and a plurality of indoor unit devices, wherein the shunting device comprises a gas liquid separator, a first heat exchange assembly, a first electronic expansion valve, a second heat exchange assembly and a second electronic expansion valve; when the variable refrigerant volume system is in a pure heating mode, the shunting device controls the first electronic expansion valve to be completely switched off, and when the variable refrigerant volume system is controlled to enter a liquid discharge state, the shunting device periodically switches off and switches on the first electronic expansion valve. According to the variable refrigerant volume system, the first electronic expansion valve is controlled, and a high-temperature gaseous state refrigerant is enabled to completely enter heating indoor units, so that the heating effect of the variable refrigerant volume system can be ensured.

The invention discloses a multi-connected air conditioner system. The v multi-connected air conditioner system comprises at least two indoor units and an outdoor unit, and the outdoor unit is connected with the at least two indoor units; the outdoor unit is connected with a control device through a route device, the outdoor unit receives user commands sent by the control device through the route device, the indoor units are selected according to the user commands, and a control instruction is sent to the selected indoor unit to control the selected indoor unit to operate. The invention further discloses a variable refrigerant flow control method, the outdoor unit and a storage medium. According to the multi-connected air conditioner system and control method, the outdoor unit and the storage medium, the outdoor unit is connected with a network and is connected with the route device, the outdoor unit is connected with the indoor units, the outdoor unit is uniformly connected with external devices, a communication module is not required to be arranged on each indoor unit, and therefore control of the indoor units and the outdoor unit of the variable refrigerant flow is guaranteed, and cost is saved.

The invention relates to the technical field of overheat degree control of thermodynamic reverse circulation systems and provides a method for controlling overheat degree of a thermodynamic reverse circulation system through variable refrigerant flow. The method includes the steps of collecting an actual overheat degree value T in every collecting cycle and subtracting the actual overheat degree value T from a set overheat degree value T0 to obtain an overheat degree difference value e; subtracting a current collecting cycle e1 from a previous collecting cycle e0 and dividing an collecting cycle t by a difference value to obtain a variation rate de / dt; collecting a compressor rotation speed n and subtracting a compressor rotation speed n1 of the current collecting cycle e1 from a compressor rotation speed n0 of the previous collecting cycle e0 so as to obtain a variation value deltan of the compressor rotation speed; selecting a proportion coefficient Kp, an integration coefficient Ki and a differential coefficient Kd according to the overheat degree difference value e and the variation rate de / dt; computing an opening value by inputting the selected coefficients into a PID controller; acquiring an corrected opening value based on the variation value deltan of the compressor rotation speed; adding the opening value and the corrected opening value to obtain an actual opening value. By the method, the problem that existing systems have time lag in overheat degree control is solved.

The invention provides an adapter and an intelligent control system of a variable refrigerant flow air conditioner. The adapter of the variable refrigerant flow air conditioner comprises a home bus system (HBS) coding and decoding circuit, a central processing unit and a RS485 driving circuit, wherein the HBS coding and decoding circuit is used for acquiring a first protocol signal sent by the variable refrigerant flow air conditioner and performing decoding processing; the central processing unit is used for converting a decoded first protocol signal to a second protocol signal and performing analytical processing to obtain operation state data of the air conditioner; the RS485 driving circuit is used for sending the operation state data of the air conditioner to a control terminal which the variable refrigerant flow air conditioner corresponds to; and conversion between the first protocol signal and the second protocol signal is rapidly achieved through the HBS coding and decoding circuit, the central processing unit and the RS485 driving circuit in the adapter of the variable refrigerant flow air conditioner, intelligent control over the variable refrigerant flow air conditioner, incompatible with the control terminal of a second communication protocol, of a first communication protocol is finally achieved through the control terminal of the second communication protocol, and the convenience and practicability of the variable refrigerant flow air conditioner in practical application are improved.

The invention discloses a variable refrigerant flow air conditioning system. The variable refrigerant flow air conditioning system comprises a host computer system and an air-conditioner refrigerant system; the air-conditioner refrigerant system comprises an indoor unit subsystem and an outdoor unit subsystem, wherein the indoor unit subsystem comprises at least one indoor unit, and the outdoor unit subsystem comprises at least one outdoor unit; the host computer system is used for obtaining the indoor unit set temperature, the indoor environment temperature and the outdoor unit environment temperature and obtaining recorded values according to the outdoor unit environment temperature; and the host computer system controls the indoor unit according to the indoor unit set temperature, the indoor environment temperature and the recorded values. By means of the variable refrigerant flow air conditioning system, effective energy-saving operation can be achieved on the premise that the user comfort is obtained, the energy-saving effect is good, the intelligence degree is high, and the user requirement is met. The invention further discloses a control method for the variable refrigerant flow air conditioning system.

A modular stand system is adjustable in the transverse direction and height and is adapted for HVAC system components that need to be elevated above a support surface. In certain embodiments, the modular stand systems herein are advantageously used to support HVAC variable refrigerant flow (VRF) units.

The invention belongs to the technical field of air conditioning, and relates to a variable refrigerant flow air conditioning system and a defrosting control method thereof. An outdoor heat exchangeris divided into at least two heat exchange units arranged in parallel from top to bottom, and each heat exchange unit is provided with a temperature sensor and an outdoor unit throttling part. In thedefrosting mode, on the basis of the magnitude relation between the average temperature value of all the heat exchange units and the temperature value of each heat exchange unit, the opening degree ofthe outdoor unit throttling parts corresponding to the heat exchange units is adjusted. Uniform refrigerant flow distribution in the defrosting process of the outdoor heat exchanger is achieved, thedefrosting speed of the middle portion and the defrosting speed of the lower portion of the outdoor heat exchanger are effectively increased, the overall defrosting time and the indoor unit cold air preventing time are shortened, and the indoor comfort and the air conditioning system reliability are ensured.

An oil-free central compressor variable refrigerant flow air conditioning system structure and method is set out. The system may be a new installation, or retrofit. Refrigerant piping spans are not limited by considerations of entrained oil flow.

The invention relates to a variable refrigerant flow system preventing compressor return and a control method thereof. The system mainly comprises a refrigerant circulating loop formed by a compressor, an oil separator, a four-way valve, an indoor unit heat exchanger, economizer, a heating electronic expansion valve assembly, an outdoor unit heat exchanger and a gas-liquid separator, an inlet formed in the evaporation side of the economizer is communicated with the bottom of the gas-liquid separator through a liquid outlet pipe, liquid refrigerant in the gas-liquid separator can be guided intothe economizer, and compressor return is prevented. The control method of the system comprises the steps that the compressor air inlet temperature and saturation temperature are compared, whether ornot a liquid return control electronic expansion valve is switched on is determined, by comparing the economizer inlet temperature with the economizer outlet temperature, the opening of the liquid return control electronic expansion valve is adjusted, and safe and efficient operation is achieved.

The invention discloses an outdoor unit of a variable refrigerant flow air-conditioning system and the variable refrigerant flow air-conditioning system.The outdoor unit comprises a main gas return pipe, a plurality of compressors and an oil separator, the compressors include the main compressor and the N auxiliary compressors, each compressor is provided with a gas return opening and an exhaust opening, the gas return opening of each compressor is connected with the main gas return pipe through a branch gas return pipe, the oil separator is provided with an inlet, an oil outlet and a discharge port, the inlet is connected with the exhaust opening of each compressor, a branch oil return pipeline is connected between each branch gas return pipe and the oil outlet, each branch oil return pipeline is connected with a first throttling device with a throttling and pressure reducing function in series, and the first throttling devices corresponding to the at least N-1 auxiliary compressors are constructed to have an opening and closing function, and each first throttling device with the opening and closing function is opened when the corresponding auxiliary compressor runs.By means of the outdoor unit, the oil return amounts of all the running compressors can be uniformly distributed.

Methods and systems for controlling temperature and humidity within a space in a building. Outdoor air and return air from the space are passed through particular equipment in a particular order. Equipment includes a secondary direct-expansion refrigeration circuit, a recovery wheel, a primary cooling coil or direct-expansion refrigeration circuit, secondary circuit coils, and a dehumidification wheel. Various embodiments include modulating the secondary circuit compressor to adjust reheat capacity at the secondary circuit condenser coil, a geothermal direct-expansion refrigeration circuit, a variable refrigerant flow subsystem, fan coil units, multiple zones, a dedicated outdoor air supply subsystem, an evaporative cooler, supplemental outdoor air, or a combination thereof. In some embodiments, supply air passes first through the recovery wheel, then through the primary cooling coil, then through the dehumidification wheel, and then to the space. Further, in some embodiments, exhaust air passes through the dehumidification wheel, and then through the recovery wheel.

The invention discloses an outdoor unit set of an air conditioning variable refrigerant volume system. The outdoor unit set comprises outdoor units, and each outdoor unit comprises a compressor, an outdoor unit heat exchanger, an electronic expansion valve, a refrigeration one-way valve and a four-way valve; two ends of the refrigeration one-way valve are communicated with two ends of the electronic expansion valve respectively; the other end of the outdoor unit heat exchanger is communicated with the other end of an indoor unit via the electronic expansion valve; the outdoor unit set of the air conditioning variable refrigerant volume system is characterized in that a high pressure sensor is arranged on a connection pipeline between the output end of the compressor and the four-way valve in any one outdoor unit; a low pressure sensor is arranged on a connection pipeline between the input end of the compressor and the four-way valve; and a secondary pressure sensor is arranged on a connection pipeline between the four-way valve and the outdoor unit heat exchanger of each of the rest of the outdoor units. According to the outdoor unit set of the air conditioning variable refrigerant volume system, the number of the pressure sensors is reduced, so that the cost is reduced.

The invention relates to the field of air conditioners, in particular to a multi-split radiation type central air conditioning system with variable refrigerant flow. The multi-split radiation type central air conditioning system comprises a central control unit, a plurality of indoor units, a plurality of outdoor units and a plurality of indoor radiation tail ends. The multiple indoor units are connected in series. The multiple outdoor units are connected in series. The multiple indoor radiation tail ends are connected in parallel. The central control unit is in signal connection with the multiple indoor units and the multiple outdoor units. The multiple outdoor units are connected with the multiple indoor units in series and then connected with the multiple indoor radiation tail ends in series. According to the multi-split radiation type central air conditioning system with variable refrigerant flow, the multiple indoor units and the multiple outdoor units are controlled through the central control unit, accordingly the control area of the whole radiation type air conditioning system is enlarged, meanwhile, the whole radiation type air conditioning system can be convenient to control, and operation becomes easier and more convenient.

The invention provides a control method and system and an air conditioner. The method is used for controlling the frequency of a compressor during heating operation of a VRF (variable refrigerant flow) air conditioning system, and the method comprises the following steps: acquiring a critical environment temperature corresponding to preset evaporation pressure of the VRF air conditioning system; detecting the outdoor environment temperature; judging whether the outdoor environment temperature is greater than the critical environment temperature; if the outdoor environment temperature is lowerthan the critical environment temperature, obtaining actual evaporation temperature of the VRF air conditioning system heating mode, and adjusting the frequency of the compressor according to the actual evaporation temperature and the preset target evaporation temperature; and under the condition that the outdoor environment temperature is larger than the critical environment temperature, obtaining the actual condensation temperature of the VRF air conditioning system heating mode, and adjusting the frequency of the compressor according to the actual condensation temperature and the preset target condensation temperature. According to the method, the cost is greatly saved, the product market competitiveness is improved, compared with previous control, system operation parameters are closerto design values, and the system operation efficiency is improved.

The invention discloses a method and device for reducing the flow noise of a refrigerant of a variable refrigerant flow system. According to the method and the device, the variable refrigerant flow system comprises a first bypass valve, a second bypass valve and a refrigerant throttling valve. The method comprises the following steps that acquiring the operating horsepower of an indoor unit; acquiring the starting capacity of the indoor unit; and controlling the first bypass valve, the second bypass valve and the refrigerant throttling valve according to the operating horsepower of the indoorunit or the starting capacity of the indoor unit. The method and the device have the advantages that the first bypass valve, the second bypass valve and the refrigerant throttling valve are controlledaccording to the operating horsepower of the indoor unit or the starting capacity of the indoor unit, so that the number of outlet flow paths of the refrigerant is changed, and therefore the flow ofthe refrigerant is promoted, the flow uniformity of the refrigerant is improved, and the flow noise of the refrigerant of the variable refrigerant flow system is reduced.

A redundant cooling method and system are provided. The method comprises: providing a plurality of variable refrigerant flow air cooling units, wherein the number of air cooling units is at least one more than required to meet a selected maximum cooling load when operating the air cooling units at up to a maximum cooling capacity; coupling the plurality of variable refrigerant flow air cooling units in thermal communication with the air in a conditioned space; determining a select optimum operating condition for each of the plurality of variable refrigerant flow air cooling units which will result in about a lowest overall energy consumption for the redundant cooling system, while maintaining an average temperature of the air in the conditioned space at a required setpoint; and operating said plurality of air cooling units in about the select optimum operating conditions for each of the air cooling units.

The embodiment of the invention provides a VRV(variable refrigerant flow) air conditioner indoor unit online detection method and device and a VRV(variable refrigerant flow) air conditioner, and relates to the technical field of VRV air conditioners. The VRV air conditioner indoor unit online detection method comprises the steps: online number of indoor units communicating with an outdoor unit normally is obtained; and when the online number is smaller than a preset value, the indoor units are controlled to execute corresponding actions according to the communication states of the indoor unitsand the outdoor unit so as to distinguish the indoor units in different communication states with the outdoor unit. Therefore, when the indoor unit abnormally communicating with the outdoor unit occurs, a user can quickly discriminate the offline indoor unit, and related personnel can be reminded in time to maintain the indoor unit.

The invention provides a frequency control method for controlling a target frequency of a variable refrigerant flow air conditioner. The frequency control method comprises the following steps of acquiring a current external environment temperature and a pressure value of an exhaust pipe of a compressor of the air conditioner; judging whether the time of continuous operation of the compressor at the moment is greater than a preset time threshold value or not; if so, adjusting the frequency of the compressor according to the pressure value; and otherwise, adjusting the frequency of the compressor according to the external environment temperature. Different frequency control modes are selected according to the operating time of the compressor. In an initial starting stage of the compressor, parameters of a system are unstable. The frequency of the compressor is adjusted according to the parameter: the external environment temperature which is not affected by system operation in the air conditioner. When the compressor operates stably, the frequency of the compressor is adjusted according to a pressure value of the exhaust pipe, so that the frequency control method is suitable for controlling the frequency of the compressor, including a water heater, in an indoor unit of the variable refrigerant flow air conditioner.

The invention discloses a variable refrigerant flow air conditioner, a wireless control method of the air conditioner, and a wireless controller. The method comprises the steps of sending a search signal to search target indoor units, determining first feedback signals as confirmation feedback signals when the first feedback signals emitted by the searched target indoor units pass verification, marking the target indoor units as connectable indoor units, displaying the target indoor units, judging distances of the target indoor units according to the strength of the confirmation feedback signals, ordering the target indoor units marked as the connectable indoor units according to the distances, and then controlling the target indoor units marked as the connectable indoor units. According to the wireless control method of the variable refrigerant flow air conditioner, the nearby target indoor units can be searched by wireless automatic search and distance recognition steps, and the distances can be recognized according to the strength of the wireless signals, so that a user can selectively control the target indoor units according to the distances of the target indoor units marked as the connectable indoor units.

The invention relates to a gas heat pump and electric variable refrigerant flow combination system and a control method thereof. An outdoor unit of the system comprises a gas variable refrigerant flowunit and an electric variable refrigerant flow unit which are controlled uniformly by a controller of the system. The gas variable refrigerant flow unit and the electric variable refrigerant flow unit communicate through a line. An indoor unit of the system comprises a plurality of indoor unit modules which communicate to any outdoor unit through lines. A clock is arranged on a master control substrate in the controller. The gas variable refrigerant flow unit uses a gas engine to drive a compressor to operate for refrigerating and heating circulation. The electric variable refrigerant flow unit drives the compressor by electric power to operate for refrigerating and heating circulation. By taking the gas variable refrigerant flow unit and the electric variable refrigerant flow unit as outdoor units simultaneously and controlling the gas variable refrigerant flow unit and the electric variable refrigerant flow unit independently, the system is driven to work in different time periods by using different energy sources by making full use of price difference of different energy sources, thereby creating advantageous conditions for improving the economical benefit.