65results about How to "Maximize energy saving" patented technology

A wireless electrical power metering system is provided. A processor having a multichannel power line transceiver, a wireless transceiver, and a power meter attached thereto measures power consumption information on a power line inductively coupled with the power meter. The processor converts the power consumption information into IP-based data, and transmits same over the wireless transceiver. The information can be wirelessly received by a remote monitoring station or transmitted across the Internet for storage, analysis, and billing. The processor generates appliance control signals and generates same across the multichannel power line transceiver to remotely control appliances in response to power consumption trends. The processor provides firewall capabilities, and relays information between a wired or wireless network and a power line network, thereby expanding the size of existing household networks. Further, the processor allows multiple dwellings to be networked using power lines, and households to be connected to the Internet via a power line network. The electrical power metering system also includes Global Positioning System (GPS), biometric scanning, emergency alert reception, and environmental monitoring capabilities.

A wireless electrical power metering system is provided. A processor having a multichannel power line transceiver, a wireless transceiver, and a power meter attached thereto measures power consumption information at a location. The processor converts the power consumption information into IP-based data, and transmits same over the wireless transceiver. The information can be wirelessly received by a remote monitoring station or transmitted across the Internet for storage, analysis, and billing. The processor can remotely control appliances in response to power consumption trends. The processor can relay information between a wired or wireless network and a power line network, to allow multiple dwellings to be networked using power lines, and households to be connected to the Internet via a power line network. The electrical power metering system also includes Global Positioning System (GPS), biometric scanning, emergency alert reception, and environmental monitoring capabilities.

A method and / or apparatus providing for an improved user interface for controlling a complex thermostat or Energy Management System is disclosed. The invention provides for a user selection of an energy management profile from a number of preconfigured stored profiles, the selection of the profile by the user then providing setting or control of many complex control settings for an energy management system or thermostat. The profiles can be labelled and / or ordered in levels or percentages of energy savings, and / or given names meaningful in making a selection.

An electrical energy storage system for maximizing the utilization of renewable energy. In the system an inverter connected to at least one battery module is integrated with a grid power source and home or office electrical devices. Additionally, a renewable energy source can be included in the system. A controller is used to control the components for reducing demands on the grid power source during peak demand periods and for maximizing the utilization of the renewable energy source connected to the system.

A system, method and computer program product for managing power consumption in a system comprising at least two computing devices. The at least two computing devices are organized as part of active computing device group or a ready computing device group, the ready computing devices configured into various modes of readiness including a standby mode, a hibernating mode, and a power-off mode. A control device receives obtained sensed parameters indicative of the processing load at the group of active computing devices and determines a “Readiness” index value representing a state of system readiness which is a function of a transition time parameter representing a time for moving one or more computing devices from the second group of ready computing devices to the first group of active devices in response to a service level violation. To achieve maximum power saving and yet meet various performance targets, the ready computing devices are dynamically allocated from amongst three states: standby, hibernating or power-off, based on the current readiness index value.

A system and method for controlling a matrix of light emitting diodes (LED) connected to an input line comprises a power converter for connecting to the matrix of LEDs and to the input line therebetween and for receiving from the input line an input current and an input voltage characterized by a shape and a frequency and for providing a direct current (D.C.) output for powering up the LEDs, yielding an operating current through the LEDs. The power converter includes a first current sensor for sensing the input current and a second current sensor for sensing the operating current. The system further comprises a controller for connecting to both the input line and to the power converter. The controller includes a voltage sensor for sensing the input voltage and a pre-regulator i) for receiving the operating current, the input current and the input voltage, ii) for biasing the operating current towards a target current value, and iii) for regulating the power converter to cause the input current to follow the shape and frequency of the input voltage, yielding a unity power factor and minimizing the input current harmonic distortion. The present method and system allows maximizing the energy savings, controlling current flowing in the diodes so as to obtain the maximum flux of light with the minimum energy and also allows meeting all safety, EMI, reliability and robustness requirements.

A system, method and computer program product for managing power consumption in a system comprising at least two computing devices. The at least two computing devices are organized as part of active computing device group or a ready computing device group, the ready computing devices configured into various modes of readiness including a standby mode, a hibernating mode, and a power-off mode. A control device receives obtained sensed parameters indicative of the processing load at the group of active computing devices and determines a “Readiness” index value representing a state of system readiness which is a function of a transition time parameter representing a time for moving one or more computing devices from the second group of ready computing devices to the first group of active devices in response to a service level violation. To achieve maximum power saving and yet meet various performance targets, the ready computing devices are dynamically allocated from amongst three states: standby, hibernating or power-off, based on the current readiness index value.

The present invention provides a heatpump heat water multiple air condition not only meeting the needs of cool or heat to the user, but als meeting needs of hot water, the heatpump heat water multiple air condition includes an indoor heat interchanger, an outdoor heat interchanger, a heatpump water tank and a four-way valve corresponding to the outdoor heat interchanger and the heatpump water tank, the inlet of the four-way valve and the outlet of the compressor are jointed together in a high pressure windpipe, the outlet of the four-way valve is connected to the inlet of the compressor, the normal opening end of the first four-way valve is connected to the outdoor heat interchanger, the normal closing end of the first four-way valve is connected to the inlet of the compressor, the normal opening end of the second four-way valve is connected to the heatpump water tank, the normal closing end of the second four-way valve is connected to the outlet of the second four-way valve by capillary. The invention makes the multiple air condition prepare hot water in the course of cooling or heating by controlling flow direction of each four-way valve.

An electrical energy storage system for maximizing the utilization of renewable energy. In the system an inverter connected to at least one battery module is integrated with a grid power source and home or office electrical devices. Additionally, a renewable energy source can be included in the system. A controller is used to control the components for reducing demands on the grid power source during peak demand periods and for maximizing the utilization of the renewable energy source connected to the system.

A motor controller (4) and method for maximizing the energy savings in an AC induction motor (3) at every load wherein the motor is calibrated at two or more load points to establish a control line (6), which is then programmed into a non-volatile memory (30) of the motor controller. A DSP-based closed-loop motor controller observes the motor parameters of the motor such as firing angle / duty cycles (23), voltage (37), current (9) and phase angles to arrive at a minimum voltage necessary to operate the motor at any load along the control line. The motor controller performs closed-loop control to keep the motor running at a computed target control point, such that maximum energy savings are realized by reducing voltage through pulse width modulation.

The invention discloses a building outer wall structure with double shaping phase change material layers. The building outer wall structure sequentially comprises the outer shaping phase change wall board layer, a first thermal insulation layer, a wall body layer, a second thermal insulation layer, the inner shaping phase change wall board layer from outside to inside, wherein the outer shaping phase change wall board layer and the inner shaping phase change wall board layer are respectively made of phase change materials of phase change temperatures of Tm1 and Tm2, the phase change temperature Tm1 is set to be minimum in cold load all year round in the expositing environment of the phase change temperature Tm1, and the solid phase change materials melt into liquid phase change materials when the wall board layer temperature is equal to or higher than Tm1; the phase change temperature Tm2 is set to be minimum in heat load all year round in the exposing environment of the phase change temperature Tm2, and the solid phase change materials melt into liquid phase change materials when the wall board layer temperature is equal to or higher than Tm2. The invention further designs the components and proportion of the phase change materials of the two shaping phase change wall board layers. By the building outer wall structure which is compact, high in adaptability, convenient to manufacture and maintain later, and the like, outer wall cold load and heat load can be lowered effectively, and overall energy consumption is lowered evidently.

The invention discloses an air conditioner host machine increase and decrease control method and device as well as an air conditioner system. The air conditioner host machine increase and decrease control method comprises the following steps that a calculation model of the operation power and the refrigeration / heating quantity of a host machine is obtained; the practical load demand Q0 of the air conditioner tail end is obtained; the corresponding first operation power Ni when the refrigeration / heating quantity of the single host machine is Q0 / i is respectively calculated according to the calculation model, wherein the i is a natural number not equal to zero, and is 1, 2, 3 to T, and the T is the total host machine number; the first total power consumed when i host machines are started under the first operation power Ni is respectively calculated, so that T first total powers are obtained; the host machine number corresponding to the minimum first total power in the T first total powers is determined to be the operation number of the practical host machines. The practical operation number of the host machines is controlled according to the principle that the power sum of the parallel connection host machines is the minimum, and the goal of maximizing the energy saving effect is realized, so that the energy saving effect of a cold station reaches the maximization.

The invention discloses a power supply system and an operation method of intelligent peak shifting and valley filling superimposed photovoltaic power generation. The method comprises the following steps: judging the photovoltaic power generation quantity, and determining an operation mode of the system according to the photovoltaic power generation quantity; when the photovoltaic power generation quantity is zero, operating the system by providing power supply through a storage battery pack in a peak power time period, providing power supply through the electric supply in a flat power time period, providing power supply through the electric supply and performing floating charge on the storage battery pack in a valley power time period; when the photovoltaic power generation quantity is larger than or equal to a preset volume, adopting photovoltaic power supply by the system in the peak power time period, the flat power time period and the valley power time period; when the photovoltaic power generation capacity is smaller than the preset volume, adopting the photovoltaic power supply by the system in the peak power time period, and when the generating capacity of a photovoltaic rectifier module group is smaller than the load capacity of the peak power time period, controlling the storage battery pack to discharge to supplement the insufficient photovoltaic power generation part; and adopting the photovoltaic power supply by the system in the flat power time period, and when the photovoltaic power generation capacity is smaller than the load capacity of the flat power time period, adopting the electric supply to supplement the insufficient photovoltaic power generation part, thereby effectively saving resources.

The embodiment of the invention relates to the technical field of communication and discloses a base-station control method, device and system, wherein the base-station control method includes: determining whether any carrier wave of any section of a macro base station meets a first turn-off condition, if yes, then acquiring information of each micro base station which has an overlapping coverage relation with the carrier wave of the macro base station; determining whether the micro base stations meet a second turn-off condition according to the information of each micro base station, and if yes, notifying the micro base stations which meet the second turn-off condition to execute turn-off operation. Through the base-station control method, device and system, energy consumption of a whole network is reduced.

The invention discloses an intelligent streetlight control system and method based on satellite positioning and cooperation, relates to the field of smart cities, and solves the problem that traditional streetlights cannot light in real time as required. The streetlight control system is composed of a terminal device installed in a vehicle or carried by a pedestrian, a control device installed at streetlight nodes and an intelligent streetlight cooperative control network composed of streetlight nodes. The terminal device obtain its own positional information, including latitude and longitude, direction and speed, by using a satellite positioning module, and the positional information is processed and then is transmitted to a neighboring streetlight node via a wireless link. The streetlight node receives a positional information table sent by the terminal device, shares the information with related streetlight nodes according to an electronic map, and controls the on-off states of the streetlights in accordance with an established strategy. The intelligent streetlight control system is not subject to interference of other objects, is not restricted by terrain, is precise in control, solves accurate lighting and real-time lighting, achieves on-demand intelligent lighting and carry-on streetlights, and is high in energy efficiency.

The invention discloses a heat supply system based on a water mixing device. The water mixing device comprises a secondary circulating pump, a temperature sensor and a three-way electric valve, wherein a water inlet of the primary circulating pump is connected with a boiler, a water outlet of the primary circulating pump is connected with one end of a heat exchanger, the other end of the heat exchanger is connected with a water inlet of the water mixing device, a water outlet of the water mixing device is connected with a building heat radiator of a building to be supplied with heat, the temperature sensor is arranged in a room at the tail end of the building to be supplied with heat,, in which the heat supply system is,and a temperature signal acquired by the temperature sensor is associated with an electric valve of the heat supply system. According to the invention, heat supply regulation, constant-temperature PID (Proportion Integration Differentiation) control and the water mixing device are combined, namely, the water supply temperature is controlled by using the water mixing device, and the temperature in the room at the tail end is subjected to constant-temperature PID regulation for controlling the water supply flow.

The invention discloses a six-effect evaporative crystallization device and process applied to zero discharge of industrial wastewater. The six-effect evaporative crystallization device comprises six preheaters, six groups of evaporators, a desalting unit for desalination and other components, which are operated in series connection, wherein the front five preheaters focus on recovering waste heat of evaporative condensation water, and the preheater at the tail end is used for heating concentrated brine entering the first effect evaporator to close to a bubbling point; the front four effect evaporators are falling-film evaporators, the back two effect evaporators are forced circulation type evaporators, the front four effect evaporators are mainly used for evaporating water, the back two effect evaporators focus on concentration, and the brine is finally concentrated to a slurry with certain solid content; the slurry is desalinated by virtue of the desalting unit; and evaporated condensate exchanges heat with the concentrated brine to ensure that steam heat energy can be fully used, thereby improving the utilization ratio of the heat energy. The six-effect evaporative crystallization device can be widely applied to evaporative desalination working sections of various industries, and is particularly suitable for 'zero' discharge treatment systems for the industrial wastewater.

The invention discloses a big data heat supply energy management and control platform system based on a PDCA system. The big data heat supply energy management and control platform system comprises: aheat source control system, a heating station control system, a heat consumer room temperature collection system, an operation toll collection system and other data source systems which are respectively used to provide related data sources and control bottom-layer execution mechanisms; a big data server cluster and a relational database server cluster respectively used for data existence, storageof a big data analysis and data parameter relation table and Web website publishing; a big data analysis module used for data analysis processing; a checking index system used for checking of rated indexes; a whole network dispatching optimization module used for load prediction and hot source dispatching for a heat supply whole network; a tracking checking system used for checking of the rated index, benchmarking of the energy consumption and cost statistics trace analysis; and a big data analysis model used for link continuous online dynamic optimal improvement according to an operation implementation condition. The big data heat supply energy management and control platform system can achieve the purposes of reducing the energy consumption and improving the energy efficiency.

The invention relates to a far-end intelligent energy-saving control system and method for a central air-conditioner. A control interface output end of a terminal controller is in series connection to control fan power and an electromagnetic valve of cold / hot circulating water, and a central control computer sends signal to the terminal controller via a communication control module between layers. The terminal controller directly controls the fan power and the electromagnetic valve of cold / hot circulating water according to optimal control parameters sent by the central control computer. The system is mounted outside of the control system of the central air-conditioner, the terminal controller can be controlled to open and close the fan power and the electromagnetic valve of the cold / hot circulating water in an air outlet directly. In the system, modifying of the controller of a central air conditioning unit is avoided and the operation of the far-end fan power and the electromagnetic valve of the cold / hot circulating water directly is adjusted directly as the central air conditioning unit adjusts the operation of the unit according to the actual temperature or the flow of the return water automatically. The system is superimposed to the prior central air-conditioner other than changing the original set of the central air-conditioner.

The invention discloses a comprehensive system using power line carriers to achieve remote control on LED lamps. The comprehensive system comprises an input module, an A / D converting module, a power line carrier sending module, a power line carrier receiving module and a PWM control module. Connection modes between the modules are that the input module, the A / D converting module and the power line carrier sending module form a dimming module, the input module and the A / D converting module are connected, the A / D converting module and the power line carrier sending module are connected, the power line carrier sending module and the power line carrier receiving module are connected, and the power line carrier receiving module and the PWM control module are connected.

The invention relates to the field of water heaters, in particular to a low-temperature heat-storage water heater and a heat storage control method and a water application control method thereof. A compressor, an evaporator and a condensation heat exchange pipe in a heat pump unit of the water heater are in serial connection into a refrigerant flow loop. A water tank is filled with a phase changematerial, a water supply pipe penetrates through the water tank, and the water supply pipe outside the water tank is provided with an electric heater. The condensation heat exchange pipe also penetrates through the water tank. A refrigerant in the condensation heat exchange pipe flows, and the phase change material is heated and turns into a liquid state from a solid state, so that heat storage isachieved. When the water needs to be heated, the phase change material releases heat and performs heat exchange with the water supply pipe. The phase change material can heat the water in real time,the size of the water heater is reduced, and the phase change material can store heat and save energy. When the water at the high temperature is used, a heat exchanger adopts electric heating, and through control of a heat pump system and an auxiliary electric heating structure, different water usage demands of users can be met. The electric heater is used for assisting in heating, the interior ofthe water heater is reasonably controlled, the water usage demand of the users is met, and the energy saving effect of the water heater with a heat pump is achieved to the greatest extent.

The invention discloses a building outer wall structure with double shaping phase change material layers. The building outer wall structure sequentially comprises the outer shaping phase change wall board layer, a first thermal insulation layer, a wall body layer, a second thermal insulation layer, the inner shaping phase change wall board layer from outside to inside, wherein the outer shaping phase change wall board layer and the inner shaping phase change wall board layer are respectively made of phase change materials of phase change temperatures of Tm1 and Tm2, the phase change temperature Tm1 is set to be minimum in cold load all year round in the expositing environment of the phase change temperature Tm1, and the solid phase change materials melt into liquid phase change materials when the wall board layer temperature is equal to or higher than Tm1; the phase change temperature Tm2 is set to be minimum in heat load all year round in the exposing environment of the phase change temperature Tm2, and the solid phase change materials melt into liquid phase change materials when the wall board layer temperature is equal to or higher than Tm2. The invention further designs the components and proportion of the phase change materials of the two shaping phase change wall board layers. By the building outer wall structure which is compact, high in adaptability, convenient to manufacture and maintain later, and the like, outer wall cold load and heat load can be lowered effectively, and overall energy consumption is lowered evidently.

An apparatus and method controls an environmental control system to maintain a differential pressure between a room and one or more adjacent areas by (1) determining a differential pressure error based on the differential pressure and a differential pressure set point using a proportional-integral-derivative (PID) controller; (2) increasing an air change per hour set point whenever one or more first parameters are satisfied; (3) decreasing the air change per hour set point whenever one or more second parameters are satisfied; and (4) sending one or more control signals to the environmental control system that maintain the differential pressure between the room and the one or more adjacent areas by adjusting: (a) the leading airflow to be approximately equal to the air flow change set point multiplied by a volume of the room divided by 60, and (b) the tracking airflow to maintain a volume differential set point.

The invention provides a bladder type energy accumulator which is of five structures and has an external air source and an oil level control function. The energy accumulator can horizontally stretch or retreat to deform to store energy, can allow a bladder to be taken out integrally for in-situ replacement, can horizontally or vertically deform to store energy, or has a pull-rod fixed-capacity / variable-capacity control function. According to the operating principle, energy storage is realized through horizontal deformation of the bladder or through main horizontal deformation and auxiliary vertical deformation. According to the structure of the bladder, the diameter of the bladder is half that of a cylinder, the two ends of the bladder are fixed and are open, or one end of the bladder is closed, and the bladder becomes thinner gradually from the two ends to the middle. Oil and gas are separated by the bladder, gas is guided into the bladder, oil is injected outside the bladder, energyconversion is achieved by means of gas pressure changes caused by alternate changes of the volume of oil and the volume of gas, and thus, the purposes of energy storage and release are realized. An automatic alarm device is arranged for oil shortages. Inlet oil can be magnetically filtered. The bladder type energy accumulator has the advantages that the structure is simple, the manufacturing costis lower, machining, manufacturing and maintenance are convenient, and responding is more sensitive; and intelligent control can be achieved, and the bladder type energy accumulator is suitable for alarge-capacity energy storage and closed-loop hydraulic balance system.

The invention discloses an air source heat pump heating system capable of cascade heat storage, heat supply and defrosting. The air source heat pump heating system involves a refrigerant circuit and aheating hot water circuit, wherein the refrigerant circuit involves an evaporator, a four-way reversing valve gas-liquid separator, a compressor, a cascade phase change heat storage device, a condenser, a filter and an expansion valve; and the heating hot water circuit comprises the cascade phase change heat storage device, the condenser, a hot water circulation pump, and a heating end device. According to the air source heat pump heating system, compared with the prior art, stored heat can be directly used for heating, the intermediate link is greatly reduced, and the energy utilization efficiency of the system is improved; the system can achieve six operational mode adjustments according to working conditions, and the economic benefits and the energy-saving benefits are maximized; and the cascade phase change heat storage device provided by the air source heat pump heating system can be divided into a middle-low-temperature heat storage unit for heating and a lower-temperature heatstorage unit for defrosting of a heat pump, so that the cascade utilization of the heat is realized.

An efficient heat-exchange fresh-air conditioning plant comprises through-wall air supplying and exhausting tubes, fresh-air supplying channels, an indoor air returning and exhausting channel, an angle type fan coil unit and an indoor fresh-air outlet. The through-wall air supplying and exhausting tubes are arranged on two sides of a wall corner and are connected with air supplying and exhausting channel accesses. An air supplying channel comprises left and right triangular channels and transverse channels partitioned via transverse partition plates, and an exhausting channel comprises a middle triangular channel and transverse channels partitioned via transverse partition plates and transverse guide plates. Supplied air and exhausted air are transferred by metal partition plates via vertical channels and the transverse channels in a multi-pass reciprocating manner and are subjected to heat exchange mutually. After being subjected to heat exchange, fresh-air is delivered to a surface air cooler by the angle type fan coil unit to be subjected to heat exchange, then cooled hot air is delivered to an indoor air outlet, and the clean cooled hot air is supplied to the inside of a building. The fresh-air conditioning plant is novel in appearance, compact in structure, low in energy consumption and high in quality.

The invention discloses an energy-saving building temperature control system. The energy-saving building temperature control system comprises a water pump, a water source heat pump unit, a tail end heat exchanger and a control mechanism, wherein the water pump communicates to a river bottom or a lakebed. The water source heat pump unit is connected with a water pump pipeline. The tail end heat exchanger is arranged in an indoor ares of a user and is connected with the water source heat pump unit through a first circulating pump. The control mechanism comprises a master controller and a control panel. The master controller controls operation of the water pump, the water source heat pump unit and the first circulating pump according to preset starting parameters within preset time after starting, and adjusts operation of the water pump, the water source heat pump unit and the first circulating pump according to operation parameters input on the control panel after the preset time is up, so that constant-temperature and constant-pressure operation of the system is achieved. By means of the characteristic that river water or lake water around a building is warm in winter and cool in summer, the cold and hot requirements of the building are met through heat exchange of the river water or the lake water, meanwhile, use of the land area is reduced, the heat exchange efficiency is improved, and maximum energy saving of the system is achieved through constant-temperature and constant-pressure control.

The invention provides an air conditioning device, which comprises an indoor unit, an outdoor unit and a connecting pipeline. The indoor unit consists of an indoor fan, a heat pipe circulating evaporator, a compressor circulating evaporator, an indoor fan wind direction switching device and an indoor controller, and the indoor controller controls the indoor fan wind direction switching device to switch a wind direction of the indoor fan; the outdoor unit comprises an outdoor fan, a heat pipe circulating condenser, a compressor circulating condenser, an outdoor fan wind direction switching device, a compressor, a throttling device and an outdoor controller, and the outdoor controller is used for starting or stopping the compressor and the throttling device and controlling the outdoor fan wind direction switching device to switch a wind direction of the outdoor fan; the connecting pipeline consists of a heat pipe connecting pipeline and a compressor circulating connecting pipeline; the heat pipe circulating evaporator is connected with the heat pipe circulating condenser by the heat pipe circulating connecting pipeline; and the compressor circulating evaporator is connected with the compressor circulating condenser by the compressor circulating connecting pipeline. The air conditioning device has the advantages that a heat pipe circulating working mode is preferentially adopted when the condition of the temperature is met, and energy conservation and emission reduction effects are realized more effectively.

The invention relates to a direct current frequency-conversion speed-regulation temperature control system which comprises a power supply system, a PWM (pulse width modulation) fan, a variable speed fan and an AO (analogue output) drive compressor. The system is characterized in that the power supply system provides minus 48V direct current; the rotation speed of the PWM fan is adjustable so as to achieve adjustable wind speed; and the compressor is a variable speed compressor, and a flexible start mode is adopted. The temperature control method of the direct current frequency-conversion speed-regulation temperature control system of the claim 1 is utilized, the cold or heat output of the refrigerating and heating unit is mainly controlled through target unit temperature curve changes; the method for controlling the cold and heat is provided according to requirements, and the temperature requirement of the target unit can be met with less energy resource consumption; and the energy conservation maximization is realized.

The invention provides an elevator energy saving and storing device and a control method. The device comprises a weight measuring device, a calling box, a control device and executing devices. The weight measuring device is used for measuring the weight of people and objects taking an elevator; the calling box is used for detecting the floor position where the people and objects taking the elevator are located and the lifting direction of the people and objects taking the elevator; the control device is responsible for inputting the weight of all the people and objects taking the elevator and the lifting direction of the people and objects taking the elevator and determining the executing device capable of saving energy through optimal computation; transmission devices in the executing devices are alternating-current direct-current alternating-current frequency converters with controllable rectifiers, a bidirectional voltage rising and reducing charger and a storage battery set. When operating efficiency is not changed, every time an elevator car ascends with no load and descends with heavy loads, the system can be in an energy-saving operating state. According to the elevator energy saving and storing device and the control method, buildings wherein two or more elevators operate can operate in the same way for a long time from the view of statistics, energy saving and consumption reducing are obvious, the control principle is clear, the additional cost is low, and safety and reliability are high.