A central heating system

Abstract

The application belongs to the technical field of heat supply, and relates to a central heating system, comprising: a variable frequency fan, heat exchange coil groups, air volume and coil switching controllers, temperature and air volume sensors, a communication interface, a fan box body and an air outlet. The application connects multiple heat exchange coil groups in the form of a three-way commutating valve, so that air volume flows through the heat exchange coil groups in sequence or simultaneously for heat exchange after being generated by the variable frequency fan. The variable frequency fan and the heat exchange coil groups are both provided with air volume and coil switching controllers, temperature and air volume sensors and a communication interface, so that users can select and use different numbers of heat exchange coil groups and different air volume and water volume for air conditioning according to their own air conditioning needs, so that the air conditioner can be accurately controlled, has small temperature fluctuation and low energy consumption.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of heating technology, and relates to a central heating system. BACKGROUND

[0002] The current central heating technology mode in northern cities is to increase the indoor temperature of buildings to the thermal comfort requirement at one time through centralized heat delivery. Due to the habit of welfare households to uniformly heat the whole space and all-weather, with the increase of per capita building area, a large number of idle space and idle time cause the increase of invalid heating. Under the current market-oriented heating system, the heat company collects heating fees and then reaches a heating quality agreement with the heat user. In order to avoid complaints of individual indoor temperature not meeting the standard, the heat company is forced to increase the heating capacity of the whole system, and the normal operation is over-temperature operation, and the window is wasted seriously.

[0003] In order to realize the research and development of key equipment such as centralized heating to ensure basic room temperature and meet the different heating needs of individuals, and promote the implementation of the central-distributed combined heating mode in northern cities (the heating mode will use the existing central heating system to ensure that the building reaches the basic temperature of one-time heating, and uniformly charges according to the area. On this basis, the indoor temperature is continuously increased to the secondary heating standard temperature through distributed heating equipment or system, and the user can adjust the temperature according to the building space and time use demand, and charges according to the actual heat consumption.), it is necessary to use the matched terminal device. The traditional air conditioning fan coil is used for heat exchange of the central air conditioning system, that is, the fan and the heat exchange coil supply cold or heat to the indoor. However, the fan coil in the prior art has the following defects: 1. The existing fan coil device usually has a fixed number of heat exchange coils, and usually uses a method of adjusting a single parameter, that is, changing the air speed to keep the water flow unchanged, or changing the water flow to keep the air speed or air supply unchanged. These methods have great defects, which limit the adjustment range to some extent, resulting in unsatisfactory adjustment effect. 2. Adjusting the air speed or air supply is easy to cause large temperature fluctuation, affecting the comfort of the user; and adjusting the water flow through the coil to adjust the air supply temperature is easy to cause high energy consumption, increasing the use cost of the user. 3. In order to adapt to the user return water temperature reuse scene of centralized heating, when the heat exchange medium temperature is low, in order to meet the heating demand, it is easy to cause large fluctuation of the air supply temperature. Therefore, a device capable of precise control and low temperature fluctuation and energy consumption is needed to solve the above problems. SUMMARY

[0004] The fan coil device of the application is placed in a room with existing heating terminal (central heating cannot meet the user's thermal comfort requirement under lower heating temperature) or a room without heating terminal (central heating is provided for other rooms in the building, and part of the rooms are not provided with central heating terminal), and the internal heat exchange pipeline is connected to the return water pipeline of the central heating system, further reducing the return water temperature, increasing the supply-return temperature difference, improving the central heating efficiency of the supply system, fully utilizing the heat energy, further reducing the supply water temperature of the central heating system, and reducing the overall energy consumption of the central heating system; and the fan coil device is adjusted in wide frequency.

[0005] The technical scheme adopted by the application to solve the technical problem is: a central heating system, comprising: a variable frequency fan, a heat exchange coil group, a wind volume and coil switching controller, a temperature and wind volume sensor, a communication interface, a fan box, an air supply port, and a multi-terminal system utilizing the return water of the central heating system; the variable frequency fan is used to generate wind volume flow, and the wind speed thereof can be adjusted through the wind volume and coil switching controller; the heat exchange coil group has high-temperature water flowing inside to heat the wind volume flow flowing outside; each heat exchange coil group can be independently controlled in working state to realize adjustment of the heat exchange quantity of the heat exchange coil group; the wind volume and coil switching controller is used to receive temperature and wind volume setting signals, and adjust the wind speed of the variable frequency fan and control the working state of each heat exchange coil in the heat exchange coil group according to the setting signals; the temperature and wind volume sensor is used to detect the real-time temperature and wind volume of the variable frequency fan and each heat exchange coil group, and transmit the detection signals to the wind volume and coil switching controller; the communication interface is used to communicate with external equipment and receive temperature and wind volume setting signals; the fan box is used to install and fix the equipment; and the air supply port is used to deliver the wind volume flow heated by the heat exchange coil group after being generated by the variable frequency fan to the heating user.

[0006] The user side part of the central heating system comprises: a central heating water supply main pipe, a central heating water return main pipe, a central heating terminal water supply pipe, a central heating terminal water return pipe, a fan coil terminal water supply No.1 pipe, a fan coil terminal water return No.1 pipe, a water supply pipe central heating water collector, a heating scheme 1 building room type, a central heating terminal radiator, a wide frequency adjustment fan coil device terminal, a heating scheme 2 building room type, a heating scheme 3 building room type, a central heating terminal water supply pump, a central heating terminal water supply pipe valve, a central heating terminal water return pipe valve, a central heating terminal water supply pipe branch pump, a central heating terminal water supply pipe branch valve, a central heating terminal water return pipe branch valve, a fan coil device terminal No.1 pipe water supply pump, a fan coil device terminal No.1 pipe water supply valve, a fan coil device terminal No.1 pipe water return valve, a fan coil device terminal No.2 pipe water supply pump, a fan coil device terminal No.2 pipe water supply valve, a fan coil device terminal No.2 pipe water return valve, a fan coil terminal water supply No.2 pipe, a fan coil terminal water return No.2 pipe; the central heating terminal radiator is connected to the water supply pipe central heating water collector, then heat is taken from the central heating water supply main pipe, after heat exchange, the water return temperature returns to the central heating water return main pipe, and the heat exchange flow can be adjusted by the water pump or valve on the central heating terminal water supply pipe and the central heating terminal water return pipe; the wide frequency adjustment fan coil device terminal takes heat from the central heating water return main pipe through the fan coil terminal water supply No.1 pipe and the fan coil terminal water supply No.2 pipe, then returns to the central heating water return main pipe through the fan coil terminal water return No.1 pipe and the fan coil terminal water return No.2 pipe, and the heat exchange flow can be adjusted by the water pump or valve on the fan coil terminal water supply No.1 pipe, the fan coil terminal water supply No.2 pipe, the fan coil terminal water return No.1 pipe and the fan coil terminal water return No.2 pipe; in addition, the heating scheme 1 building room type represents a building or room that can meet the indoor thermal comfort requirement by central heating, the heating scheme 2 building room type represents a building or room that cannot meet the requirement of the wide frequency adjustment fan coil device terminal by central heating, and the wide frequency adjustment fan coil device terminal can also be placed alone in the heating scheme 3 building room type without other terminals.

[0007] The fan box body is in the shape of a rectangular parallelepiped, the frequency conversion fan, the heat exchange coil group and the air supply port are fixedly connected to the fan box body, the heat exchange coil group is provided in multiple groups, the heat exchange coil group is installed on the air flow passage between the frequency conversion fan and the air supply port, the heat exchange coil groups are connected, and the air flow generated by the frequency conversion fan is sequentially or dispersedly conveyed to the air supply port after passing through the heat exchange coil groups.

[0008] The air volume and coil switching controller, the temperature and air volume sensor and the communication interface are electrically connected to the frequency conversion fan and the heat exchange coil group respectively.

[0009] The water inlet pipe and the water outlet pipe of the heat exchange coil group are respectively connected with the central heating return water pipeline; in the use process, the user sets the required temperature and air volume through the external device, the air volume and coil switching controller receives the setting signal, and then adjusts the air speed of the variable frequency fan and controls the working state of each heat exchange coil in the heat exchange coil group according to the setting value. The temperature and air volume sensor detects the actual temperature and air flow of the variable frequency fan and the heat exchange coil group in real time, and transmits the detection signal to the air volume and coil switching controller. The air volume and coil switching controller adjusts the air flow of the variable frequency fan, the temperature and air flow of the heat exchange coil group, and the heat exchange working quantity of the heat exchange coil group according to the actual situation, so as to realize the temperature and air volume adjustment in a large range. Compared with the traditional fan coil, the device has more gears, and the air volume can be adjusted from 20% to 100% by changing the heat exchanger area and the fan frequency. The size of the heat exchange area and the fan frequency is set to be one-to-one corresponding to the air volume adjustment range, that is, if there are 5 groups of heat exchange coils, 1 group corresponds to 20%, 2 groups correspond to 40%, 3 groups correspond to 60%, 4 groups correspond to 80%, and 5 groups correspond to 80%. The fan frequency adjusts the specific air volume range in each coil, that is, when 2 groups are used, the fan frequency is adjusted to realize the adjustment between 20% and 40%. The above adjustment method improves the flexibility and accuracy of temperature and air volume adjustment.

[0010] Preferably, the heat exchange coil group is provided with a coil and an air flow transmission pipe connected with the coil, and the two ends of the air flow transmission pipe are respectively connected with the variable frequency fan and the air outlet. The air flow transmission pipe is used for sending air flow to the coil for heat transfer.

[0011] Preferably, the air volume and coil switching controller includes a processor, a memory, a communication module and a power module. The processor is used for processing data collected by the temperature and air volume sensor and executing control. The memory is used for storing data. The communication module is used for communicating with external devices and controllers. The power module is used for providing power for the controller. The communication module is electrically connected with the communication interface. The intelligent devices such as the controller and the sensor can detect the actual temperature and air volume in real time, and transmit the detection signal to the controller for processing and adjustment, thereby improving the automation degree and adjustment accuracy of the device.

[0012] Preferably, the heat exchange coil group is provided with a three-way reversing valve connected between the coils, and the effect of changing the heat exchange area is realized by adjusting the valve at each heat exchange coil.

[0013] Preferably, the external device includes a smart phone, a tablet computer and a computer.

[0014] Preferably, the air supply outlet is located below the heat exchange coil group; the lower air supply mode cooperates with the wide frequency adjustment mode, so that the device is suitable for a central heating return water heating system, such as an apartment, an office building, and the like, and can meet the heating requirements in different environments, and is widely used in various occasions to meet the needs of different users;

[0015] The user side part of the central heating system is a multi-end system using the central heating system heating return water. In order to introduce three different heating schemes, three cases are summarized together. The wide frequency adjustment fan coil device is installed on the user return heating water pipe side, including a central heating end heat exchanger, a central heating end heat exchanger supply and return valve, a central heating end heat exchanger water pump, a central heating end supply and return valve, a central heating end water pump, a fan coil end supply and return valve, and a fan coil end water pump. The central heating end can be a floor radiant heating or other end equipment such as a radiator. The fan coil device can be placed in a room with an existing end for heat supplement, or can be placed alone for heating. The system includes a central heating water supply main pipe, a central heating return water main pipe, a central heating end water supply pipe, a central heating end return water pipe, a fan coil end water supply pipe, a fan coil end return water pipe, a water supply pipe central heating distribution tank, a central heating radiator end, a wide frequency adjustment fan coil device end, a water pump, a control valve, a room with only a central heating end, a double-end room, and a fan coil end room.

[0016] The central heating end water pump serves as a main heating device for the central heating end user, extracts heat from the central heating pipe network to supply to the distribution tank, and meets the heating requirements. The distribution tank supplies hot water to the radiator device in each room for heat exchange, and then the return water returns to the return water main pipe through the distribution tank, thereby realizing the central heating end heating process.

[0017] The fan coil end water pump serves as a main heating device for the end user, extracts residual heat from the return water pipe of the central heating pipe network to supply to the room with the wide frequency adjustment fan coil, and meets the heating requirements. The return water after heat exchange by the fan coil returns to the return water pipe of the central heating pipe network, thereby realizing the independent heating of the fan coil end and the heating process of the fan coil as a supplementary heat source.

[0018] The two ends, multiple group valves, multiple water pumps and multiple rooms can realize the function of multiple combination heating through control. Scheme 1: only considering central heating, the user with relatively low heat comfort requirement (under the premise that the central heating temperature is not high, the target is to reduce energy consumption), only needs to take heat from the central heating pipe network to provide heat for the central heating end room; Scheme 2: only considering waste heat heating, the user with certain heat comfort requirement, adopts a wide frequency regulation fan coil device end to take heat from the return water pipe network to provide heat for the fan coil end room; Scheme 3: considering central heating and waste heat at the same time, the user with high heat comfort requirement, adopts a double-end form, when the heat taken from the central heating pipe network is not enough to meet the indoor heat comfort requirement, the wide frequency fan coil is started to take heat from the return water pipe to further reduce the return water temperature, so as to meet the heat comfort requirement and reduce the overall system energy consumption.

[0019] To realize the above scheme, the following steps should be included:

[0020] Step 1: judging the heating scheme adopted according to the heat comfort requirement of different users;

[0021] Step 2: first, satisfying the heating of the central heating end device. If scheme 1 is adopted, the water supply valve and water pump of the central heating end water supply pipe are used for water supply, the valves before and after the heat collector and radiator are used for adjustment, and the heat collector is connected to the radiator end to supply heat to each room or building;

[0022] Step 3: second, satisfying the heating of the fan coil end. If scheme 2 is adopted, the water supply valve and water pump of the fan coil end water supply pipe are used for water supply, the valves on the supply and return water sides of the fan coil are used for adjustment, and finally the room or building with the fan coil end is heated;

[0023] Step 4: finally, realizing double-end heating in combination with the above two schemes. If scheme 3 is adopted, first, the water supply valve and water pump of the central heating end water supply pipe are used for water supply, the valves before and after the heat collector and radiator are used for adjustment, and the heat collector is connected to the radiator end to supply heat to each room or building; if the heat comfort requirement is still not met, the water supply valve and water pump of the fan coil end water supply pipe are used for water supply, the valves on the supply and return water sides of the fan coil are used for adjustment, and finally the room or building with the fan coil end is heated; finally, the heat comfort requirement is met.

[0024] Step 5: no matter which scheme is adopted, all return water should be ensured to flow into the return water pipe according to the control signal through the return water valve.

[0025] The control idea of the application is:

[0026] S1 Scheme 1: For users with low indoor thermal comfort requirements, heat should be taken from the central heating pipe network through appropriate control methods to meet the most basic thermal comfort requirements.

[0027] S1-1 Detect the indoor temperature T of each room in the building n1 , T n2 , T n3 , … … T ni (not all rooms are shown in the figure, only one room represents multiple similar rooms), according to the indoor temperature, the total flow Q required by all rooms at this time is calculated by the sensor and controller, and the total flow is adjusted by adjusting the water pump.

[0028] S1-2 Determine whether the indoor temperature Tn is less than the temperature controller set temperature Ts is less than the temperature controller set temperature, adjust the water pump and control valve after the water distributor and the valve of the corresponding other rooms of the same type), if the indoor temperature Tn is greater than the temperature controller set temperature Ts, the temperature control valve of the corresponding room is closed, if the indoor temperature Tn is less than the temperature controller Ts set temperature, the temperature control valve of the corresponding room is opened and controlled.

[0029] S1-3 Finally determine whether all rooms meet the requirements, if all rooms meet the requirements, end the control; if there are rooms that do not meet the requirements, delay for a period of time and then adjust the temperature of each room, determine whether the total flow Q adjustment valve is opened to the maximum or closed to the smaller; if the total flow adjustment valve is opened to the maximum, delay and control the circulating water pump to increase or decrease the flow; if the current total flow adjustment valve is closed to the smaller, open and adjust the valve first; repeat the above process until the system total flow Q requirement is met and all room temperatures reach the requirements.

[0030] S2 Scheme 2: Consider using the waste heat of the return water pipe network for heating, users with certain requirements for thermal comfort and using wide frequency regulation fan coil heating, the device takes heat from the return water pipe, its corresponding valve and water pump are used to adjust the flow to make the water temperature entering the fan coil relatively stable; the sensor collects the user set temperature Ts, indoor temperature Tn, average supply air temperature Tc, supply air speed Vd, fan coil supply air volume G, heat exchange coil usage group number N, heat exchange coil total inlet and outlet water temperature Tpg and Tph of the fan coil system at the current time; the above parameters are transmitted to the controller to calculate the most suitable indoor thermal comfort requirement of the current supply air volume G, and to judge whether the adjustment of the coil number N can meet the current situation; if the coil number N cannot be adjusted to meet the current situation, further change the frequency of the variable frequency fan to adjust the supply air volume G, calculate the optimal set point of the fan frequency and the number of heat exchange coils used; the control signal of the best set point is transmitted to the air volume and coil switching controller to realize the adjustment of the overall supply air temperature and air volume.

[0031] S2-1 detects the current indoor temperature Tn, the fan-coil supply air temperature Tc, and the set temperature Ts, and calculates the temperature difference ATns = Tn - Ts between the indoor temperature and the set temperature.

[0032] S2-2 determines the fan air volume G and the number of coils N according to ATns, and outputs an initial signal. When the value of ATns reaches the maximum limit ATnsmax, the fan air volume output is 20%; when ATns reaches the minimum limit ATnsmin, the fan air volume output is 100%; and when the value of ATns is between ATnsmax and ATnsmin, the fan air volume is output in proportion between 20% and 100%.

[0033] S2-3 opens the fan, the central heating water supply pipeline valve, and the water pump, detects the indoor temperature Tn and the fan-coil supply air temperature Tc, and continues to calculate the value of ATns.

[0034] S2-4 if the value of ATns is within the temperature fluctuation range set by the user, the fan air volume output and the number of coils in use remain unchanged;

[0035] S2-5 if the value of ATns is outside the temperature fluctuation range set by the user, the following steps are continued: if the indoor temperature Tn is higher than the set temperature Ts, S2-6 is executed; if the indoor temperature Tn is lower than the set temperature Ts, S2-9 is jumped to.

[0036] S2-6 determines whether the number of coils N in use has reached the maximum value that can be used.

[0037] S2-7 if the number of coils N in use has not reached the maximum value, the number of coils N in use is adjusted according to the fan-coil supply air temperature Tc, and after the adjustment is completed, S2-3 is returned to.

[0038] S2-8 if the number of coils N in use has reached the maximum value, and the air volume G is also the maximum, S2-15 is executed; otherwise, S2-9 is jumped to.

[0039] S2-9 detects whether the fan air volume G is within the range of 20% to 100% at this time, and if it is within the range, S2-11 is executed; otherwise, S2-10 is executed.

[0040] S2-10 at this time, the adjustment range of the air volume is adjusted according to the situation of ATns. When the value of ATns is between ATnsmax and ATnsmin, the fan air volume G is output in proportion between 20% and 100%. If the output fan air volume G after the signal is loaded is greater than 100%, the air volume G is reduced according to the degree that is less than ATnsmin, and the reduction range is within 50%; and then S2-3 is returned to.

[0041] S2-11 If the number of heat exchange coil groups N is large at this time, S2-12 is executed, otherwise the current number of groups N is maintained and then S2-13 is executed.

[0042] S2-12 The number of heat exchange coil groups N is reduced and then S2-3 is returned.

[0043] S2-13 If the current fan air volume G is greater than 95%, S2-14 is executed, otherwise the current air volume is output and then S2-3 is returned.

[0044] S2-14 The fan air volume G is reduced according to the user's demand and then S2-3 is returned.

[0045] S2-15 The fan air volume G and the number of heat exchange coil groups N remain unchanged and then S2-3 is returned.

[0046] S2-16 The appropriate supply air temperature Tc is finally output.

[0047] When the control of S2-1 to S2-16 is performed, the valves and water pumps on the water supply and return pipelines of the fan coil are used to maintain the relative stability of the fan coil supply and return water temperatures Tpg and Tph.

[0048] The maximum limit value ΔTnsmax and the minimum limit value ΔTnsmin in S2-2 can be changed by the user.

[0049] S3 Scheme 3: Combine the above two control methods to reduce the return water temperature and improve the delivery capacity of the central heating system to meet the thermal comfort while further reducing energy consumption. The actual situation should be considered comprehensively for use. Since the user properties, spatial positions and heat exchanger properties of various central heating systems are different, a targeted design scheme must be designed when the terminal technology is transformed. The control idea is to use the room temperature Tn in the central heating radiator terminal room as the control point of the water pump 20 heat supply flow. When the water pump 20 reaches the rated flow and still cannot meet the indoor (building type 18) thermal comfort requirements, the system automatically starts the fan coil 17 and adjusts the fan heat pipeline water pump 29 to supplement, and automatically closes when no supplement is needed.

[0050] S3-1 The indoor temperature Tn of the building type is detected at the beginning of heating, the required flow of all rooms at this time is calculated through the sensor and controller, and the flow is adjusted by adjusting the water pump.

[0051] S3-2 Determine whether the indoor temperature is less than the temperature controller set temperature, adjust the water pump and control valve, if the indoor temperature Tn is greater than the temperature controller set temperature Ts, the temperature control valve of the corresponding room is closed, if the indoor temperature Tn is less than the temperature controller Ts set temperature, the temperature control valve of the corresponding room is opened and controlled.

[0052] S3-3 judges whether the room temperature meets the requirement, if yes, the regulation ends; if not, judges whether the current flow regulating valve is opened to the maximum; if yes, controls the water circulating pump to increase or decrease the flow until the room temperature requirement is met.

[0053] S3-4 when the valve and the water pump have reached the maximum, the room temperature still cannot meet the user's thermal comfort requirement, at this time, the fan coil device is started, the water pump is opened, and the valve is adjusted.

[0054] S3-5 after the fan coil device is started, the indoor heat is supplemented according to the current indoor temperature, and the control process S2-1 to S2-16 is repeated, and the difference between the indoor temperature and the set temperature is changed, that is, the temperature difference △Tns=Tn-Ts is changed, at this time, the room temperature Tns3 after the central heating and the higher set temperature Tss3 should be considered, and the temperature difference △Tns3=Tns3-Tss3.

[0055] S3-6 the indoor temperature value that meets the user's satisfaction is obtained after the above-mentioned cycle ends.

[0056] The beneficial effects of the present application are:

[0057] 1. The present application controls multiple heat exchange coil group systems, so that the air flow generated by the frequency conversion fan flows through the heat exchange coil group in sequence or simultaneously for heat exchange, and the air flow and the coil switching controller, the temperature and air flow sensor and the communication interface are arranged on the frequency conversion fan and the heat exchange coil group, so that the user can select different numbers of heat exchange coil groups and different air flow and water flow for air conditioning according to the user's air conditioning demand, so that the air conditioner can be accurately controlled, the temperature fluctuation is small, and the energy consumption is low.

[0058] 2. The present application connects the heat exchange coil group to the central heating return water pipeline, fully utilizes the return water heat in the central heating return water pipeline, and reduces the energy consumption of the air conditioner.

[0059] 3. After the central heating return water is supplied by the fan coil, the load of the existing urban heating system can be greatly reduced, and the carbon reduction rate of the urban heating operation can reach more than 20%, and the surplus heating capacity of the existing heat source can be used as a backup for urban development expansion.

[0060] 4. For the central heating problem in the middle and lower reaches of the Yangtze River, because the overall winter temperature in this area is relatively high, the wide frequency regulation fan coil device is used for distributed heating to directly meet the thermal comfort requirement. BRIEF DESCRIPTION OF DRAWINGS

[0061] Figure 1 It is a schematic diagram of a central heating system;

[0062] Figure 2is the heat exchange coil diagram in the fan-coil device;

[0063] Figure 3 is the central heating user side system form suitable for the wide frequency regulation fan-coil device;

[0064] Figure 4 is the heating scheme 1 control flow chart;

[0065] Figure 5 is the wide frequency fan-coil control flow chart;

[0066] Figure 6 is the heating scheme 2 control flow chart;

[0067] Figure 7 is the heating scheme 3 control flow chart.

[0068] In the figure: 1, variable frequency fan; 2, heat exchange coil group; 3, air volume and coil switching controller; 4, temperature and air volume sensor; 5, communication interface; 6, fan box; 7, air supply outlet; 8, central heating water supply main pipeline; 9, central heating return water main pipeline; 10, central heating terminal water supply pipeline; 11, central heating terminal return water pipeline; 12, fan-coil terminal water supply No. 1 pipeline; 13, fan-coil terminal return water No. 1 pipeline; 14, water supply pipeline central heating distribution water tank; 15, heating scheme 1 building room type; 16, central heating terminal radiator; 17, wide frequency regulation fan-coil device terminal; 18, heating scheme 3 building room type; 19, heating scheme 2 building room type; 20, central heating terminal water supply pump; 21, central heating terminal water supply pipeline valve; 22, central heating terminal return water pipeline valve; 23, central heating terminal water supply pipeline branch water pump; 24, central heating terminal water supply pipeline branch valve; 25, central heating terminal return water pipeline branch valve; 26, fan-coil device terminal No. 1 pipeline water supply pump; 27, fan-coil device terminal No. 1 pipeline water supply valve; 28, fan-coil device terminal No. 1 pipeline return water valve; 29, fan-coil device terminal No. 2 pipeline water supply pump; 30, fan-coil device terminal No. 2 pipeline water supply valve; 31, fan-coil device terminal No. 2 pipeline return water valve; 32, fan-coil terminal water supply No. 2 pipeline; 33, fan-coil terminal return water No. 2 pipeline. DETAILED DESCRIPTION

[0069] The related technologies in the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0070] ReferenceFigures 1 to 7 A central heating system, comprising: a variable frequency fan 1, a heat exchange coil group 2, a fan volume and coil switching controller 3, a temperature and fan volume sensor 4, a communication interface 5, a fan box 6, an air outlet 7; the variable frequency fan 1 is used to generate air flow, the air speed of which can be adjusted by the fan volume and coil switching controller 3, the heat exchange coil group 2 has high-temperature water flowing inside to heat the air flow flowing outside, each heat exchange coil group 2 can be independently controlled to work in a state to realize the adjustment of the heat exchange quantity of the heat exchange coil group 2, the fan volume and coil switching controller 3 is used to receive a temperature and fan volume setting signal and adjust the air speed of the variable frequency fan 1 and control the working state of each heat exchange coil in the heat exchange coil group 2 according to the setting signal, the temperature and fan volume sensor 4 is used to detect the real-time temperature and air volume of the variable frequency fan 1 and each heat exchange coil group 2 and transmit the detection signal to the fan volume and coil switching controller 3, the communication interface 5 is used to communicate with external equipment and receive a temperature and fan volume setting signal, the fan box 6 is used to install and fix the equipment, and the air outlet 7 is used to deliver the air flow heated by the heat exchange coil group 2 after being generated by the variable frequency fan 1 to air conditioning users;

[0071] The fan box 6 is in the shape of a rectangular parallelepiped, the variable frequency fan 1, the heat exchange coil group 2 and the air outlet 7 are fixedly connected to the fan box 6, the heat exchange coil group 2 is provided in multiple groups, the heat exchange coil group 2 is installed on the air flow channel between the variable frequency fan 1 and the air outlet 7, the heat exchange coil groups 2 are connected in parallel or in series, and the air flow generated by the variable frequency fan 1 is sequentially or dispersedly delivered to the air outlet 7 after passing through the heat exchange coil groups 2;

[0072] The fan volume and coil switching controller 3, the temperature and fan volume sensor 4 and the communication interface 5 are respectively electrically connected to the variable frequency fan 1 and the heat exchange coil group 2, and the fan volume and coil switching controller 3 is respectively electrically connected to the temperature and fan volume sensor 4 and the communication interface 5;

[0073] The water inlet pipe and the water outlet pipe of the heat exchange coil group 2 are respectively communicated with a central heating return water pipeline; in the use process, a user sets the required temperature and air volume through external equipment, the fan volume and coil switching controller 3 receives the setting signal and adjusts the air speed of the variable frequency fan 1 and controls the working state of each heat exchange coil in the heat exchange coil group 2 according to the setting value. The temperature and fan volume sensor 4 detects the actual temperature and air volume of the variable frequency fan 1 and the heat exchange coil group 2 in real time and transmits the detection signal to the fan volume and coil switching controller 3, the fan volume and coil switching controller 3 adjusts the air volume of the variable frequency fan 1, the temperature and air volume of the heat exchange coil group 2 and the heat exchange working quantity of the heat exchange coil group 2 according to the actual situation to realize the adjustment of the temperature and air volume in a large range; compared with the traditional fan coil, the device has more gears and can realize the adjustment of the air volume from 20% to 100%, thereby improving the flexibility and accuracy of the temperature and air volume adjustment.

[0074] Reference Figure 3, the user side part of the central heating system is a multi-terminal system for utilizing the return water of the central heating system, three different heating schemes are introduced, three cases are collected together, the wide frequency regulation fan coil device is installed on the user return heating water pipe side, including the central heating terminal heat exchanger, the central heating terminal heat exchanger supply and return valve, the central heating terminal heat exchanger water pump, the central heating terminal supply and return valve, the central heating terminal water pump, the fan coil terminal supply and return valve, the fan coil terminal water pump, wherein the central heating terminal can be a floor radiant heating or other terminal equipment such as a radiator, the fan coil device can be placed in the room with the existing terminal for heat supplement, or can be placed alone for heating. The system includes a central heating water supply main pipe 8, a central heating return water main pipe 9, a central heating terminal water supply pipe 10, a central heating terminal return water pipe 11, a fan coil terminal water supply pipe 12, 32, a fan coil terminal return water pipe 13, 33, a water supply pipe central heating distribution tank 14, a central heating radiator terminal 16, a wide frequency regulation fan coil device terminal 17, a water pump 20, 23, 26, 29, a control valve 21, 22, 24, 25, 27, 28, 30, 31, a central heating terminal room 15, a heating scheme 3 building room type 18, a heating scheme 2 building room type 19. Among them,

[0075] Further, the two terminals, multiple groups of valves, multiple water pumps and multiple rooms can realize the function of multiple combined heating through control. Scheme 1: only considering central heating, the user with relatively low thermal comfort requirement (targeting at reducing energy consumption under the premise of low central heating temperature), only needs to take heat from the central heating pipe network to provide heat for the central heating terminal room 15; Scheme 2: only considering waste heat heating, the user with certain thermal comfort requirement adopts a new wide frequency regulation fan coil to take heat from the return water pipe network to provide heat for the heating scheme 2 building room type 19; Scheme 3: considering both central heating and waste heat, the user with high thermal comfort requirement adopts a double-terminal form, when the heat taken from the central heating pipe network is insufficient to meet the indoor thermal comfort requirement, the wide frequency fan coil is started to take heat from the return water pipe for heating, further reducing the return water temperature, meeting the thermal comfort requirement while reducing the overall system energy consumption.

[0076] Further, the control idea of the heating scheme 1 is as follows: S1 scheme 1: for the user with low indoor thermal comfort requirement, when taking heat from the central heating pipe network, a suitable control method should be used to meet the basic thermal comfort requirement.

[0077] S1-1, the indoor temperature of each room of the building of type 15 is detected, and the total flow Q required by all rooms at this time is calculated by sensors and controllers according to the indoor temperature, and the total flow is adjusted by adjusting the water pump 20.

[0078] S1-2, whether the indoor temperature Tn is less than the temperature controller set temperature Ts is less than the temperature controller set temperature, the water pump 23 after the water pump 23 and the control valve 24, 25 and the valve corresponding to other rooms of the same type 15 are adjusted, if the indoor temperature Tn is greater than the temperature controller set temperature Ts, the temperature control valve of the corresponding room is closed, if the indoor temperature Tn is less than the temperature controller Ts set temperature, the temperature control valve of the corresponding room is opened and controlled.

[0079] S1-3, finally, whether all rooms meet the requirements, if all rooms meet the requirements, the control is ended, if there are rooms that do not meet the requirements, the temperature of each room is adjusted after a period of time, and it is judged whether the total flow Q adjusting valve 21 is opened to the maximum or closed to the smaller, if the total flow Q adjusting valve 21 is opened to the maximum, the flow of the circulating pump 20 is increased or decreased after a period of time, if the total flow Q adjusting valve 21 is closed to the smaller, the valve 21 is opened and adjusted preferentially, the above process is repeated until the total flow Q of the system meets the requirements and the temperature of all rooms reaches the requirements.

[0080] Further, the heat exchange coil group 2 is provided with a coil and an air flow transmission pipe connected with the coil, two ends of the air flow transmission pipe are connected with the frequency conversion fan 1 and the air outlet 7 respectively, and the air flow transmission pipe is used for sending air flow to the coil for heat transfer.

[0081] Further, the air volume and coil switching controller 3 includes a processor, a memory, a communication module and a power module, the processor is used for processing data collected by the temperature and air volume sensor 4 and executing control, the memory is used for storing data, the communication module is used for communicating with external devices and controllers, and the power module is used for providing power for the controller, and the communication module is electrically connected with the communication interface 5; the intelligent devices such as the controller and the sensor are adopted, the actual temperature and the air volume can be detected in real time, the detection signal is transmitted to the controller for processing and adjusting, and the automation degree and the adjusting precision of the device are improved.

[0082] Further, the external device includes: a smart phone, a tablet computer, a computer.

[0083] Further, the air supply port 7 is located below the heat exchange coil group 2; the lower air supply mode cooperates with the wide frequency adjustment mode, so that the device is suitable for central heating return water heating systems, such as apartment buildings, office buildings and other buildings, and can meet the heating needs in different environments, and is widely used in various occasions to meet the needs of different users.

[0084] Further, the heating scheme 2 control idea is: S2 scheme 2: considering using the residual heat of the return water pipe network for heating, the user who has certain requirements for thermal comfort and uses the wide frequency adjustment fan coil heating, the device takes heat from the return water pipe, and the corresponding valve 27, 28 and water pump 26 are used to adjust the flow to make the water temperature entering the fan coil relatively stable; the sensor collects the user set temperature Ts, indoor temperature Tn, average supply air temperature Tc, supply air speed Vd, fan coil supply air volume G, heat exchange coil group number N, heat exchange coil total inlet and outlet water temperature Tpg and Tph of the fan coil system at the current time; the above parameters are transmitted to the controller to calculate the current most suitable indoor thermal comfort requirement air supply volume G, and judge whether the coil number N after adjustment can meet the current situation; if the coil number N after adjustment still cannot meet the current situation, further change the frequency of the variable frequency fan to adjust the air supply volume G, and calculate the optimal fan frequency and heat exchange coil usage number best set point; the control signal of the best set point is transmitted to the air volume and coil switching controller to realize the adjustment of the overall air supply temperature and air volume.

[0085] S2-1 detects the current indoor temperature Tn, the fan coil supply air temperature Tc, and the set temperature Ts, and calculates the temperature difference ATns=Tn-Ts between the indoor temperature and the set temperature.

[0086] S2-2 determines the fan air volume G and the coil usage number N according to ATns, and outputs the initial signal. When the value of ATns reaches the maximum limit ATnsmax, the fan air volume output is 20%; when ATns reaches the minimum limit ATnsmin, the fan air volume output is 100%; when the value of ATns is between ATnsmax and ATnsmin, the fan air volume is output in proportion between 20% and 100%.

[0087] S2-3 opens the fan, the central heating water supply pipe valve and the water pump, detects the indoor temperature Tn and the fan coil supply air temperature Tc, and continues to calculate the value of ATns.

[0088] S2-4 if the value of ATns is within the user set temperature fluctuation range, the fan air volume output and the heat exchange coil usage number remain unchanged;

[0089] S2-5 If the value of ΔTns is outside the temperature fluctuation range set by the user, the following steps are continued: if the indoor temperature Tn is higher than the set temperature Ts, S2-6 is continued, and if the indoor temperature Tn is lower than the set temperature Ts, S2-9 is jumped to.

[0090] S2-6 It is judged whether the current number of heat exchange coils in use N has reached the maximum value that can be used.

[0091] S2-7 If the number of heat exchange coils in use N has not reached the maximum value, the number of heat exchange coils in use N is adjusted according to the air supply temperature Tc of the air supply fan, and after the adjustment is completed, S2-3 is returned to.

[0092] S2-8 If the number of heat exchange coils in use N has reached the maximum value, and the air volume G is also the maximum, S2-15 is executed, otherwise, S2-9 is jumped to.

[0093] S2-9 At this time, it is detected whether the air volume G of the air supply fan is within the range of 20-100%, and if it is within the range, S2-11 is executed, otherwise, S2-10 is executed.

[0094] S2-10 At this time, the air volume adjustment range is adjusted according to the situation of ΔTns. When the value of ΔTns is between ΔTnsmax and ΔTnsmin, the air volume G of the air supply fan is output in proportion within the range of 20-100%. If the output air volume G of the air supply fan after the signal is loaded is greater than 100%, the air volume G is reduced according to the degree that is currently less than ΔTnsmin, and the reduction range is within 50%; and then S2-3 is returned to.

[0095] S2-11 If the number of heat exchange coils in use N is relatively large at this time, S2-12 is executed, otherwise, the current number of groups N is maintained and then S2-13 is executed.

[0096] S2-12 The number of heat exchange coils in use N is reduced, and then S2-3 is returned to.

[0097] S2-13 If the air volume G of the air supply fan is greater than 95% at present, S2-14 is executed, otherwise, the current air volume is output and then S2-3 is returned to.

[0098] S2-14 The air volume G of the air supply fan is reduced by a certain percentage according to the user's demand, and then S2-3 is returned to.

[0099] S2-15 The air volume G of the air supply fan and the number of heat exchange coils N remain unchanged, and then S2-3 is returned to.

[0100] S2-16 The appropriate air supply temperature Tc is finally output.

[0101] Further, the control of S2-1 to S2-16, the valves (27, 28) and the water pump (26) on the water supply and return pipeline of the fan coil are used to maintain the relative stability of the fan coil supply and return water temperature Tpg and Tph.

[0102] Further, the maximum limit value ATnsmax and the minimum limit value ATnsmin in S2-2 can be changed by the user.

[0103] Further, the control idea of the heating scheme 3 is: S3 scheme 3: combined with the above two control modes, reduce the return water temperature to improve the delivery capacity of the central heating system, meet the thermal comfort and further reduce the energy consumption. According to the actual situation, the use should be considered comprehensively, because the nature of the users, the space position and the heat exchanger of each central heating system are different, so the design scheme must be designed according to the situation. The control idea is to take the temperature Tn in the room of the central heating radiator terminal as the control point of the water pump 20, when the water pump 20 reaches the rated flow and still cannot meet the heat comfort requirement of the heating scheme 3 building room type 18, the system automatically starts the fan coil 17 and adjusts the water pump 29 of the fan heating pipeline to supplement, and automatically closes when no supplement is needed.

[0104] S3-1 heating starts to detect the indoor temperature Tn of the heating scheme 3 building room type 18, calculates the required flow of all rooms at this time through the sensor and controller, and adjusts the flow by adjusting the water pump 23.

[0105] S3-2 judges whether the indoor temperature is less than the set temperature of the temperature controller, adjusts the water pump 23 and the control valves 24, 25, if the indoor temperature Tn is greater than the set temperature Ts of the temperature controller, the temperature control valve of the corresponding room is closed, if the indoor temperature Tn is less than the set temperature Ts of the temperature controller, the temperature control valve of the corresponding room is opened and controlled.

[0106] S3-3 judges whether the room temperature meets the demand, if it meets the demand, the control ends; if the room does not meet the demand, it is judged whether the flow regulating valve 24, 25 is opened to the maximum; if the flow regulating valve 24, 25 is opened to the maximum, the flow of the hot water circulating pump 23 is increased or decreased until the room temperature requirement is met.

[0107] S3-4 when the valves 24, 25 and the water pump 23 have reached the maximum value, the room temperature still cannot meet the user's thermal comfort requirement, at this time the fan coil device 17 is started, the water pump 29 is opened, and the valves 30, 31 are adjusted.

[0108] S3-5 After the fan-coil device is started, the indoor temperature is heated according to the current indoor temperature, and the repeated control process S2-1 to S2-16 is repeated, and the difference between the indoor temperature and the set temperature ATns=Tn-Ts is changed, at this time, the room temperature Tns3 after the central heating and the higher set temperature Tss3 should be considered, and the temperature difference ATns3=Tns3-Tss3.

[0109] S3-6 After the above-mentioned cycle is finally ended, the user is satisfied with the indoor temperature value.

[0110] In summary, in order to realize the research and development of the key equipment of the centralized heating to ensure the basic room temperature and meet the different needs of individual heating mode, the implementation of the centralized-distributed combined heating mode in northern towns is promoted. The wide frequency adjustment fan-coil device for central heating return water heating and its corresponding system are introduced, and through the heating scheme under three different terminal forms and the cooperative control of multiple heat exchange coil groups in the wide frequency adjustment fan-coil device, the air flow generated by the variable frequency fan flows through the heat exchange coil group in sequence or at the same time for heat exchange, and the air flow and coil switching controller, temperature and air flow sensor and communication interface are arranged on the variable frequency fan and heat exchange coil group, so that the user can select and use different numbers of heat exchange coil groups and different air flow, volume and heat exchange capacity for heating temperature adjustment according to the user's own heating demand, so that the air conditioner can be accurately controlled, the temperature fluctuation is small, and the energy consumption is low, so the application has wide application prospect.

[0111] It should be emphasized that: the above is only the preferred embodiment of the present application, not any form of limitation on the present application, any simple modification, equivalent change and modification of the above embodiment according to the technical essence of the present application still belongs to the scope of the technical solution of the present application.

Claims

1. A central heating system, characterized in that Broadband adjustment fan coil device end (17) includes: variable frequency fan (1), heat exchange coil group (2), air volume and coil switching controller (3), temperature and air volume sensor (4), communication interface (5), fan box (6), air supply port (7); The variable frequency fan (1) is used to generate air flow, the heat exchange coil group (2) has flowing high temperature water inside to heat the air flow flowing outside, the air volume and coil switching controller (3) is used to receive temperature and air volume setting signal, and adjust the air speed of the variable frequency fan (1) and control the working state of each heat exchange coil in the heat exchange coil group (2) according to the setting signal, the temperature and air volume sensor (4) is used to detect the real-time temperature and air volume of the variable frequency fan (1) and each heat exchange coil group (2) and transmit the detection signal to the air volume and coil switching controller (3), the communication interface (5) is used to communicate with external equipment and receive temperature and air volume setting signal, the fan box (6) is used to install fixed equipment, and the air supply port (7) is used to deliver the air flow heated by the heat exchange coil group (2) after being generated by the variable frequency fan (1) to air conditioning users. The user side of the central heating system comprises: a central heating water supply main pipe (8), a central heating water return main pipe (9), a central heating terminal water supply pipe (10), a central heating terminal water return pipe (11), a fan coil terminal water supply No. 1 pipe (12), a fan coil terminal water return No. 1 pipe (13), a water supply pipe central heating water collector (14), a heating scheme 1 building room type (15), a central heating terminal radiator (16), a wide frequency adjustment fan coil device terminal (17), a heating scheme 2 building room type (19), a heating scheme 3 building room type (18), a central heating terminal water supply pump (20), a central heating terminal water supply pipe valve (21), a central heating terminal water return pipe valve (22), a central heating terminal water supply pipe branch pump (23), a central heating terminal water supply pipe branch valve (24), a central heating terminal water return pipe branch valve (25), a fan coil device terminal No. 1 pipe water supply pump (26), a fan coil device terminal No. 1 pipe water supply valve (27), a fan coil device terminal No. 1 pipe water return valve (28), a fan coil device terminal No. 2 pipe water supply pump (29), a fan coil device terminal No. 2 pipe water supply valve (30), a fan coil device terminal No. 2 pipe water return valve (31), a fan coil terminal water supply No. 2 pipe (32), a fan coil terminal water return No. 2 pipe (33); the central heating terminal radiator (16) is connected to the water supply pipe central heating water collector (14), then takes heat from the central heating water supply main pipe (8), and returns the heat exchange water temperature to the central heating water return main pipe (9) after heat exchange; the heat exchange flow can be adjusted by the water pump or valve on the central heating terminal water supply pipe (10) and the central heating terminal water return pipe (11); the wide frequency adjustment fan coil device terminal (17) takes heat from the central heating water return main pipe (9) through the fan coil terminal water supply No. 1 pipe (12) and the fan coil terminal water supply No. 2 pipe (32), then returns to the central heating water return main pipe (9) through the fan coil terminal water return No. 1 pipe (13) and the fan coil terminal water return No. 2 pipe (33), and the heat exchange flow can be adjusted by the water pump or valve on the fan coil terminal water supply No. 1 pipe (12), the fan coil terminal water supply No. 2 pipe (32), the fan coil terminal water return No. 1 pipe (13) and the fan coil terminal water return No. 2 pipe (33); in addition, the heating scheme 1 building room type (15) represents a building or room that can meet the indoor thermal comfort requirement by central heating, the heating scheme 2 building room type (19) represents a building or room that cannot meet the requirement of the wide frequency adjustment fan coil device terminal (17) for additional heat by central heating, and the wide frequency adjustment fan coil device terminal (17) can also be placed alone in the heating scheme 3 building room type (18) without other terminals; The fan box (6) is a cuboid, the frequency conversion fan (1), the heat exchange coil group (2), and the air outlet (7) are fixedly connected on the fan box (6), the heat exchange coil group (2) is provided with multiple groups, the heat exchange coil group (2) is installed on the air flow channel between the frequency conversion fan (1) and the air outlet (7), the heat exchange coil group (2) is connected in parallel or in series, the air flow generated by the frequency conversion fan (1) is sequentially sent to the air outlet (7) after passing through or dispersing through the heat exchange coil group (2); The air volume and coil switching controller (3), the temperature and air volume sensor (4), and the communication interface (5) are respectively electrically connected with the frequency conversion fan (1) and the heat exchange coil group (2), and the air volume and coil switching controller (3) is respectively electrically connected with the temperature and air volume sensor (4) and the communication interface (5); The water inlet pipe and the water outlet pipe of the heat exchange coil group (2) are respectively connected with the central heating return water pipe; The central heating water supply main pipe (8), the central heating return water main pipe (9), the central heating terminal water supply pipe (10), the central heating terminal return water pipe (11), the water supply pipe central heating sub-distributor (14), the heating scheme 1 building room type (15), the central heating terminal radiator (16), the central heating terminal water supply pump (20), the central heating terminal water supply pipe valve (21), the central heating terminal return water pipe valve (22), the central heating terminal water supply pipe branch pump (23), the central heating terminal water supply pipe branch valve (24), and the central heating terminal return water pipe branch valve (25) jointly form a heating scheme 1, which is used for considering only central heating, and the user with relatively low heat comfort requirement, and is used for reducing energy consumption under the premise that the central heating temperature is not high; The fan coil terminal water supply No. 1 pipe (12), the fan coil terminal return water No. 1 pipe (13), the wide frequency adjustment fan coil device terminal (17), the heating scheme 2 building room type (19), the fan coil device terminal No. 1 pipe water supply pump (26), the fan coil device terminal No. 1 pipe water supply valve (27), and the fan coil device terminal No. 1 pipe return water valve (28) jointly form a heating scheme 2, which is used for considering only waste heat heating, and the user with certain heat comfort requirement adopts the wide frequency adjustment fan coil device terminal (17) to take heat from the return water pipe network. The central heating and water supply main pipeline (8), the central heating return water main pipeline (9), the central heating terminal water supply pipeline (10), the central heating terminal return water pipeline (11), the water supply pipeline central heating and water distribution tank (14), the heating scheme 3 building room type (18), the central heating terminal radiator (16), the central heating terminal water supply pump (20), the central heating terminal water supply pipeline valve (21), the central heating terminal return water pipeline valve (22), the central heating terminal water supply pipeline branch pump (23), the central heating terminal water supply pipeline branch valve (24), the central heating terminal return water pipeline branch valve (25), the wide frequency adjustment fan coil device terminal (17), the fan coil device terminal No. 2 pipeline water supply pump (29), the fan coil device terminal No. 2 pipeline water supply valve (30), the fan coil device terminal No. 2 pipeline return water valve (31), the fan coil terminal No. 2 water supply pipeline (32), the fan coil terminal No. 2 return water pipeline (33) form a heating scheme 3, which is used for considering central heating and waste heat at the same time, and the user with high thermal comfort requirement adopts a double terminal form. When the heat taken from the central heating pipe network is not enough to meet the indoor thermal comfort requirement, the wide frequency fan coil is started to take heat from the return water pipeline for heating, further reducing the return water temperature, meeting the thermal comfort requirement while reducing the overall system energy consumption.

2. A central heating system according to claim 1, wherein The heat exchange coil group (2) is provided with a coil and an airflow transmission pipe connected with the coil, and two ends of the airflow transmission pipe are connected with the variable frequency fan (1) and the air supply outlet (7) respectively.

3. A central heating system according to claim 1, wherein The air volume and coil switching controller (3) comprises a processor, a memory, a communication module and a power module. The processor is used for processing data collected by the temperature and air volume sensor (4) and executing control. The memory is used for storing data. The communication module is used for communicating with the external device and the controller. The power module is used for providing power for the controller. The communication module is electrically connected with the communication interface (5).

4. A central heating system according to claim 1, wherein The external device comprises a smart phone, a tablet computer and a computer.

5. A central heating system according to claim 1, wherein The air supply outlet (7) is located below the heat exchange coil group (2).

6. A central heating system according to claim 1, wherein The heat exchange coil group (2) switches the heat exchange area through a three-way valve and the temperature and air volume sensor (4).

7. A central heating system according to claim 1, wherein The number of the heat exchange coil group (2) and the variable frequency fan (1) corresponds to the 20%-100% air volume adjustment gear.

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