CN114754424A - Secondary circulation variable flow central air conditioning system - Google Patents

Secondary circulation variable flow central air conditioning system Download PDF

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Publication number
CN114754424A
CN114754424A CN202210369612.2A CN202210369612A CN114754424A CN 114754424 A CN114754424 A CN 114754424A CN 202210369612 A CN202210369612 A CN 202210369612A CN 114754424 A CN114754424 A CN 114754424A
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China
Prior art keywords
main machine
circulating pump
water
host
central air
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Pending
Application number
CN202210369612.2A
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Chinese (zh)
Inventor
张亚朝
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Individual
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Individual
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Priority to CN202210369612.2A priority Critical patent/CN114754424A/en
Publication of CN114754424A publication Critical patent/CN114754424A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/62—Control or safety arrangements characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
    • F24F11/63—Electronic processing
    • F24F11/64—Electronic processing using pre-stored data
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/70—Control systems characterised by their outputs; Constructional details thereof
    • F24F11/80—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air
    • F24F11/83—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers
    • F24F11/85—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers using variable-flow pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/89—Arrangement or mounting of control or safety devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F2110/00—Control inputs relating to air properties
    • F24F2110/10—Temperature
    • F24F2110/12—Temperature of the outside air

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Fuzzy Systems (AREA)
  • Mathematical Physics (AREA)
  • Air Conditioning Control Device (AREA)

Abstract

The invention discloses a secondary circulation variable flow central air conditioning system, which comprises a host system, a host circulating pump, a system water circulating pump, a plurality of end user ends connected in parallel and an automatic balancing section, wherein the host system comprises a water circulating pump and a water circulating pump; the main machine system comprises a main machine and an electric valve, wherein the main machine and the electric valve are connected in series to form a main machine unit and then are connected with a main machine circulating pump; the tail end user side comprises a tail end device and a tail end electric valve which are connected in series; the two ends of a plurality of end user ends are connected with a system water pump through pipelines respectively provided with a first pressure sensor and a second pressure sensor after being connected in parallel; two ends of the main machine circulating pump and the main machine system are provided with automatic balancing sections without check valves; and a PLC control cabinet is connected to the host water pump and the system water circulating pump. Compared with the prior art, the invention has the advantages that: the contradiction between the water flow required by the tail end and the host is perfectly solved; the frequency conversion of the tail end system water is completely realized; the lift of a system water pump is reduced, and the operation power consumption is reduced; the main machine circulating pump is linked with the main machine; the energy-saving operation of the central air-conditioning system is realized.

Description

Secondary circulation variable flow central air conditioning system
Technical Field
The invention relates to the technical field of air conditioning systems, in particular to a secondary circulation variable flow central air conditioning system.
Background
In a general energy-saving building, the energy consumption of central air-conditioning cooling and heating accounts for more than 60% of the energy consumption of the whole building, and a primary water circulation system is commonly used in the existing central air-conditioning system. In a primary central air-conditioning system, the energy consumption of a circulating water pump accounts for more than 30% of the energy consumption of the whole central air-conditioning system, and the circulating water pump is indispensable equipment for an energy transmission link. The primary water pump circulating system not only considers the water flow of the host machine, but also considers the water flow required by the terminal equipment; meanwhile, the total water resistance of the host, the end equipment and the system pipe network is overcome. Therefore, a large-flow high-lift water pump meeting the requirements of the maximum water flow and the maximum resistance at the same time is usually selected during model selection. Because the selected water pump has high power, the variable frequency control is designed for the water pump for energy conservation. While the main machine and the water pump are designed for full load operation, it is possible to operate at partial load for practically 90% of the time. Therefore, the following problems have not been solved effectively: 1. because the system needs to meet the lowest water flow when the central air-conditioning host works, the frequency converter has very limited participation in energy consumption regulation, and the problem of water flow matching between the tail end and the host can be solved only through the differential pressure bypass valve, so that the aim of variable-flow energy-saving operation cannot be really realized when the tail end equipment works partially. 2. When the main engine reaches the set temperature for unloading, the circulating water pump still needs to overcome the resistance of the main engine equipment to work at high power, which causes waste of energy.
Therefore, a secondary circulation variable flow central air conditioning system which not only meets the normal operation of the central air conditioning system, but also can reduce the power consumption of the water pump scientifically and reasonably needs to be researched urgently.
Disclosure of Invention
The invention aims to solve the problems mentioned in the background technology and provide an energy-saving central air-conditioning system with variable flow at the tail end of a secondary cycle.
In order to solve the technical problems, the technical scheme provided by the invention is as follows: a secondary circulation variable flow central air conditioning system comprises a host system, a host circulating pump, a system water circulating pump, an automatic balancing section and a plurality of end user ends connected in parallel;
the main machine system comprises a main machine and an electric valve, wherein the main machine and the electric valve are connected in series to form a main machine unit and then are connected in series with a main machine circulating pump, and the main machine unit and the electric valve and the automatic balancing section form a primary closed loop.
The end user side comprises end equipment in parallel connection and an end electric valve connected with the end equipment in series;
a plurality of end user ends are connected in parallel and then connected in series with a system water circulating pump, and form a secondary closed loop with the automatic balancing section;
the first pressure sensor and the second pressure sensor are respectively arranged on a main water supply pipeline and a water return pipeline which are connected in parallel at the end user side and are used for respectively detecting the pressure of supply water and the pressure of return water;
The automatic balancing section is not provided with a check valve;
and the system water circulating pump and the host circulating pump are connected with a PLC control cabinet.
As a preferred scheme, the number of the main units is not less than 1, and a plurality of the main units are connected in parallel.
As a preferred scheme, the number of the main machine circulating pumps is not less than 1, and a plurality of main machine circulating pumps are connected in parallel.
As a preferred scheme, the number of the system water circulating pumps is not less than 1, and a plurality of system water circulating pumps are connected in parallel.
As a preferred scheme, the number of the end equipment is not less than 1, and a plurality of end equipment are connected in parallel.
As a preferred scheme, the automatic balancing section is connected to two ends of a host circulating pump and a host system which are connected in series to form a public channel of a primary closed loop and a secondary closed loop.
Compared with the prior art, the invention has the advantages that: the contradiction between the water flow required by the tail end and the host is perfectly solved; the tail end system water completely realizes frequency conversion; the lift of a system water pump is reduced, and the operation power consumption is reduced; the main machine circulating pump is linked with the main machine, and the main machine can stop working when being unloaded; the running energy conservation of the central air-conditioning system is realized.
Drawings
Fig. 1 is a block diagram of the present invention.
FIG. 2 is a schematic diagram of the system water control of the present invention.
FIG. 3 is a schematic view showing the direction of water flow in example 1 of the present invention.
Fig. 4 is a schematic view showing the direction of water flow in example 2 of the present invention.
As shown in the figure: 1. the system comprises a main machine system, 2 a main machine circulating pump, 3 a system water circulating pump, 4 a tail end device, 5 a tail end electric valve, 6 an automatic balancing section, 7 and a PLC control cabinet.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it is to be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "front", "back", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of the description, but do not indicate or imply that the resulting manner or element must have a specific orientation, be configured in a specific orientation, and operate, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise explicitly stated or limited, the terms "mounted," "connected" and "connected" are to be construed broadly, e.g., as being fixedly connected, detachably connected, or integrally connected; the connection can be mechanical connection or point connection; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
With the attached drawings, the secondary circulation variable flow central air conditioning system comprises a host system, a host circulating pump, a system water circulating pump, a plurality of end user ends connected in parallel and an automatic balancing section;
the main machine circulating system (primary circulation) comprises a main machine and an electric valve, wherein the main machine and the electric valve are connected in series to form a main machine unit and then are connected with a main machine circulating pump 2;
the end circulation system (secondary circulation) comprises an end device 4 and an end electric valve 5 connected in parallel; after the end user terminals are connected in parallel, the two ends of the end user terminals are respectively provided with a first pressure sensor and a second pressure sensor and are connected with a system water pump 3;
The host system (primary system) and the tail end circulating system (secondary circulation) are connected with the shared automatic balancing section 6 to form two relatively independent and mutually associated closed loops;
and a PLC control cabinet 7 is connected to the system water circulating pump 3.
The number of the main units is not less than 1, and the main units are connected in parallel.
The number of the main machine circulating pumps 2 is not less than 1, and the main machine circulating pumps 2 are connected in parallel.
The number of the system water circulating pumps 3 is not less than 1, and the system water circulating pumps 3 are connected in parallel.
In specific implementation 1 of the invention, as shown in fig. 3, when the water flow at the tail end of the system is greater than the water flow of the host, the direction of the water flow at the b section is rightward, the water flow at the a section is the same as the water flow at the d section, the water flow at the b section is equal to the water flow at the a section minus the water flow at the c section, the temperature of the supplied water of the system is the same as the temperature of the returned water of the system after the mixed water is returned from the system and the outlet water of the host, and the temperature of the returned water of the host is the same as the temperature of the returned water of the system;
in specific implementation 2, as shown in fig. 4, when the water flow at the end of the system is smaller than the water flow of the host, the direction of the water flow at the b section is leftward, part of the water circulates twice, the water flow at the a section is the same as the water flow at the d section, the water flow at the b section is equal to the water flow at the c section minus the water flow at the a section, at this time, the water supply temperature of the system is the same as the water outlet temperature of the host, and the water return temperature of the host is the same as the temperature after the water outlet of the host and the water return of the system are mixed. At this time, because the end load is smaller than the load of the host, the return water temperature can quickly reach the operating temperature set by the host. When the backwater temperature reaches the set operation temperature of the main machine, the compressor is unloaded, the main machine circulating pump 2 correspondingly stops working when the main machine stops working, and only the system circulating water pump 3 operates under the frequency conversion working condition; the water flow of the section a is equal to that of the section b, and the water flow of the section b is equal to that of the section d, and the water flow direction of the section b is towards the right. The state is the state of the central air-conditioning system in most of the working time (partial load operation), namely the problem of water balance between the main machine and the tail end, which can be realized only by a pressure difference bypass valve for a long time when a primary system works, is solved by the invention. Because of the existence of the automatic balancing section, the automatic balancing of two circulations is realized, so that the frequency conversion adjustment of the system circulating water pump 3 can be completely carried out according to the load of the terminal equipment, and the energy-saving operation is really realized.
When the host circulating pump is in model selection, the lift selection only needs to consider overcoming the resistance of the host and the connected pipeline.
When the system circulating pump is in model selection, the lift selection only needs to consider overcoming the resistance of the tail end equipment and the connected pipeline.
The working principle of the invention is as follows: 1. according to the number of the opening of the tail end electric valve, the water flow required by the system is calculated, the PLC controls the starting of a plurality of system water circulating pumps, meanwhile, the difference between P1 and P2 is calculated according to feedback values P1 and P2 of the first sensor and the second sensor, the difference is inconvenient to keep at a given value, and meanwhile, an analog signal is output to the frequency converter.
2. According to the total power of the starting of the tail end equipment, the PLC controls the starting and stopping of the plurality of main machines and simultaneously links the electric valve with the main machine circulating pump.
3. The host operating temperature is given according to the change of the outdoor environment temperature.
The present invention and its embodiments have been described above, and the description is not intended to be limiting, and the drawings are only one embodiment of the present invention, and the actual structure is not limited thereto. In summary, those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiments as a basis for designing or modifying other structures for carrying out the same purposes of the present invention without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (6)

1. The utility model provides a secondary circulation variable flow central air conditioning system which characterized in that: the system comprises a host system, a host circulating pump, a system water circulating pump, an automatic balancing section and a plurality of end user ends connected in parallel;
the main machine system comprises a main machine and an electric valve, wherein the main machine and the electric valve are connected in series to form a main machine unit and then are connected in series with a main machine circulating pump, and the main machine unit and the electric valve and the automatic balancing section form a primary closed loop.
The end user side comprises end equipment in parallel connection and an end electric valve connected with the end equipment in series;
a plurality of end user ends are connected in parallel and then connected in series with a system water circulating pump, and form a secondary closed loop with the automatic balancing section;
the first pressure sensor and the second pressure sensor are respectively arranged on a main water supply pipeline and a main water return pipeline after the end user sides are connected in parallel and are used for respectively detecting the pressure of water supply and water return;
the automatic balancing section is not provided with a check valve;
and the system water circulating pump and the host circulating pump are connected with a PLC control cabinet.
2. The secondary circulation variable flow central air conditioning system according to claim 1, characterized in that: the number of the main units is not less than 1, and the main units are connected in parallel.
3. The secondary circulation variable flow central air conditioning system according to claim 1, characterized in that: the number of the main machine circulating pumps is not less than 1, and the main machine circulating pumps are connected in parallel.
4. The secondary circulation variable flow central air conditioning system according to claim 1, characterized in that: the number of the system water circulating pumps is not less than 1, and the system water circulating pumps are connected in parallel.
5. The secondary circulation variable flow central air conditioning system according to claim 1, characterized in that: the number of the end equipment is not less than 1, and the end equipment is connected in parallel.
6. The secondary circulation variable flow central air conditioning system according to claim 1, characterized in that: the automatic balancing section is connected to two ends of the host circulating pump after being connected with the host system in series and becomes a public channel of a primary closed loop and a secondary closed loop.
CN202210369612.2A 2022-04-08 2022-04-08 Secondary circulation variable flow central air conditioning system Pending CN114754424A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210369612.2A CN114754424A (en) 2022-04-08 2022-04-08 Secondary circulation variable flow central air conditioning system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210369612.2A CN114754424A (en) 2022-04-08 2022-04-08 Secondary circulation variable flow central air conditioning system

Publications (1)

Publication Number Publication Date
CN114754424A true CN114754424A (en) 2022-07-15

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210369612.2A Pending CN114754424A (en) 2022-04-08 2022-04-08 Secondary circulation variable flow central air conditioning system

Country Status (1)

Country Link
CN (1) CN114754424A (en)

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