Photovoltaic powered distributed ventilation system and air volume stable regulation method thereof

Abstract

The present invention proposes a photovoltaic-powered distributed ventilation system and a method for stabilizing air volume thereof, wherein the ventilation system comprises a photovoltaic power generation system, a control system, an air supply system and an exhaust system; the photovoltaic power generation system supplies power to the ventilation host (including the air supply host and the exhaust host), and the city power supplies power to the variable channel branch fan (including the variable channel branch air supply fan and the variable channel branch exhaust fan), which is a dual-engine power; the variable channel branch fan comprises a casing in which a fan and an electric valve are arranged in parallel, and the air entering the casing is discharged after passing through the fan or the electric valve in a selective manner; the control system controls the operating status of the ventilation host, the fan in the variable channel branch fan and the electric valve according to the amount of solar radiation and the branch inlet pressure. When the amount of solar radiation is sufficient, the control system makes full use of the residual pressure provided by the photovoltaic direct-drive ventilation host, reduces or even cancels the continuous operation of the fan in the variable channel branch fan, greatly reduces the energy consumption of the ventilation system, and ensures the stable air volume in each space.

Description

Technical Field

[0001] The present invention belongs to the field of ventilation systems, and in particular relates to a photovoltaic-powered distributed ventilation system and a method for stabilizing air volume thereof. Background Art

[0002] With the rapid development of economic construction and the gradual improvement of people's requirements for quality of life, the proportion of building energy consumption in the overall social energy consumption has also increased rapidly. Relevant reports point out that the total energy consumption of the entire construction process in the country accounts for 45.5% of the total national energy consumption, of which energy consumption in the building operation stage accounts for about 21% of the total national energy consumption. The "dual carbon" goal has put forward specific requirements for building carbon reduction and energy consumption reduction. Therefore, reducing energy consumption and carbon emissions during the operation of buildings is an important direction for reducing building energy consumption.

[0003] Of the total energy consumption for building operation, the energy consumed by the building's indoor air environment creation system (i.e., HVAC system) accounts for approximately 30-50% of the total energy consumption for building operation. This system mainly includes subsystems such as heating, ventilation, and air conditioning. As an important component of the building's indoor environment creation system, the building ventilation system uses two main technical means: natural ventilation and mechanical ventilation. Mechanical ventilation systems are mainly composed of fans, ventilation ducts, and air vents. They are mainly provided with stable energy resources by the building system to ensure the stable and continuous operation of the system and provide a good air environment for the building's interior. Therefore, reducing the energy consumption and carbon emissions during the operation of the mechanical ventilation system is an important technical means to reduce building operation energy consumption.

[0004] Mechanical ventilation systems mainly include two types: powered centralized ventilation systems and powered distributed ventilation (including air supply and exhaust) systems (such as those disclosed in CN201620008174.7 and CN201921641396.2). Conventional powered centralized ventilation systems and powered distributed ventilation systems both use traditional mains power distribution for energy input. In terms of energy application effect, the terminal control capability of the powered centralized ventilation system is limited, while the powered distributed ventilation system has the characteristics of adjustable terminal branch air volume, stable branch air volume, non-interference between branches, and energy-saving system. It can not only ensure personalized control of indoor ventilation, but also achieve energy saving of the transmission and distribution system compared to other conventional systems. Therefore, under the premise of ensuring good air quality and personalized adjustment capabilities at the terminal, integrating the powered distributed ventilation system with renewable energy (such as solar energy) is an important technical path for the powered distributed ventilation system to further achieve energy conservation and carbon reduction during operation.

[0005] In addition, there are two main implementation paths for the combined use of a power-distributed ventilation system and a photovoltaic system. The first is to invert the electricity generated by the photovoltaic system and store it uniformly before distributing it to each ventilation host and each branch fan. The second is to directly supply photovoltaic power to the power-distributed ventilation system host and each branch fan. In this mode, photovoltaic power generation does not go through the inversion, storage and other processes, reducing the losses caused by the inversion and storage processes. In the second method mentioned above, the output power of the photovoltaic system is highly correlated with the intensity of solar radiation. Therefore, in the photovoltaic direct drive system, the stability of the photovoltaic power cannot be guaranteed at some times, and the wind volume (including supply and exhaust volume) of the photovoltaic direct drive cannot always meet the requirements. This is in conflict with the stable wind volume demand of the terminal space. Based on the above-mentioned problem of indoor terminal wind volume stability under photovoltaic drive, it is necessary to propose a new photovoltaic-powered distributed ventilation system.

[0006] After searching, no similar technical solution to the present invention has been disclosed. Summary of the Invention

[0007] The present invention aims to solve the technical problems existing in the prior art. The first purpose of the present invention is to provide a photovoltaic-powered distributed ventilation system. The second purpose of the present invention is to provide a method for stabilizing air volume based on the aforementioned photovoltaic-powered distributed ventilation system.

[0008] In order to achieve the first purpose mentioned above, the present invention adopts the following technical solutions: a photovoltaic power distributed ventilation system, including a photovoltaic power generation system, a control system, and an air supply system for supplying air and / or an exhaust system for exhausting air; the air supply system includes an air supply main unit for supplying air, a plurality of variable channel branch air supply fans, and an air supply pipe network, the air supply pipe network includes an air supply main unit connected to the air outlet of the air supply main unit, and a plurality of air supply branches connected in parallel to the air outlet of the air supply main unit, the air outlet of the air supply branch pipe is connected to the indoor air outlet, and each air supply branch pipe is equipped with a variable channel branch air supply unit. Fan; The exhaust system includes an exhaust main unit for exhaust, several variable channel branch exhaust fans, and an exhaust pipe network. The exhaust pipe network includes an exhaust main pipe connected to the air inlet of the exhaust main unit, and several exhaust branch pipes connected in parallel to the air inlet of the exhaust main unit. The air inlet of the exhaust branch pipe is connected to the indoor exhaust outlet. Each exhaust branch pipe is equipped with a variable channel branch exhaust fan; the photovoltaic power generation system, the air supply main unit and several variable channel branch supply fans, the exhaust main unit, and several variable channel branch exhaust fans are all connected to the control system. The photovoltaic power generation system supplies power to the air supply main unit and / or the exhaust main unit. , the mains electricity is used to power several variable channel branch air supply fans and / or several variable channel branch exhaust fans, the air supply host and / or exhaust host are photovoltaic direct drive equipment; the air supply host and exhaust host are collectively referred to as ventilation hosts, and the variable channel branch air supply fans and variable channel branch exhaust fans are collectively referred to as variable channel branch fans; the variable channel branch fans all include a casing with an air inlet and an air outlet, and two air circulation paths arranged in parallel are provided in the casing, and fans and electric valves are respectively installed in the two air circulation paths, the fans are variable speed fans with adjustable speed, and the opening of the electric valve is adjustable, and the air entering the casing The air is discharged from the air outlet of the casing after passing through one of the air circulation paths in a selective manner; the photovoltaic power generation system has a solar radiation sensor for detecting the solar radiation of its photovoltaic panel, and an inlet pressure sensor for detecting the inlet pressure of the supply branch pipe and / or the inlet of the exhaust branch pipe is provided; the control system controls the operating status of the air supply main unit, fan and electric valve of the air supply system according to the solar radiation and the inlet pressure of the supply branch pipe; and / or the control system controls the operating status of the exhaust main unit, fan and electric valve of the exhaust system according to the solar radiation and the inlet pressure of the exhaust branch pipe.

[0009] The above technical solution is a dual-engine solution, which provides power for the air supply main unit and / or the exhaust main unit with a photovoltaic power generation system, and supplies power for the variable channel branch air supply fan and / or the variable channel branch exhaust fan with AC power. The operation status of the ventilation main unit and each variable channel branch fan is controlled according to the solar radiation and the inlet pressure of the air supply branch pipe / the inlet pressure of the exhaust branch pipe. When the solar radiation is sufficient, the residual pressure provided by the photovoltaic direct-driven air supply main unit / the exhaust main unit is fully utilized to reduce or even cancel the continuous operation of the fan in the variable channel branch fan on the air supply branch pipe / the exhaust branch pipe. When the solar radiation is insufficient, the air supply main unit / the exhaust main unit is not started, and the variable channel branch fan on the air supply branch pipe / the exhaust branch pipe provides the residual pressure, which greatly reduces the energy consumption of the ventilation system (including the air supply system and the exhaust system) and ensures the stability of the ventilation volume (including the supply volume and the exhaust volume) in each space.

[0010] To achieve the second above-mentioned objective, the present invention adopts the following technical solution: a method for stable adjustment of the air volume of a photovoltaic power distributed ventilation system. A solar radiation sensor detects the real-time solar radiation value I of the photovoltaic panel in real time and transmits it to the control system. In the control system, the solar radiation threshold value I0 of the air supply main machine directly driven by photovoltaic and / or the solar radiation threshold value I0' of the exhaust main machine directly driven by photovoltaic are stored. Here, I0 is the minimum solar radiation value capable of driving the air supply main machine to rotate, and I0' is the minimum solar radiation value capable of driving the exhaust main machine to rotate. When both the air supply main machine and the exhaust main machine are photovoltaic direct drive devices, the air supply main machine and the exhaust main machine are each driven by the energy output from an independent set of photovoltaic panels, or both the air supply main machine and the exhaust main machine are simultaneously driven by the energy output from a set of photovoltaic panels. When the air supply main machine and the exhaust main machine are each driven by the energy output from an independent set of photovoltaic panels, when I < I0 / I < I0', the control system controls the air supply main machine / exhaust main machine not to start, closes the electric valves of the variable channel branch air supply fans / variable channel branch exhaust fans, starts the fans of the variable channel branch air supply fans / variable channel branch exhaust fans, and each air supply branch pipe / each exhaust branch pipe adjusts the fan speed of the corresponding variable channel branch air supply fan / variable channel branch exhaust fan according to the actual air volume demand of the corresponding air supply outlet / exhaust outlet to achieve stable air volume. When I ≥ I0 / I ≥ I0', the control system controls the air supply main machine / exhaust main machine to start, controls the fan and the electric valve to open in an alternative manner according to the magnitude of the inlet pressure of the air supply branch pipe / exhaust branch pipe where each variable channel branch air supply fan / variable channel branch exhaust fan is located and the air supply branch pipe resistance / exhaust branch pipe resistance, and each air supply branch pipe / each exhaust branch pipe adjusts the opening degree of the electric valve or the fan speed according to the actual air volume demand of the corresponding air supply outlet / exhaust outlet to achieve stable air volume. When both the air supply main machine and the exhaust main machine are simultaneously driven by the energy output from a set of photovoltaic panels, the real-time solar radiation value I of the photovoltaic panel of the photovoltaic power generation system preferentially satisfies the smaller value of I0 and I0', and the ventilation main machine corresponding to the smaller value of I0 and I0' starts and controls the operation of the variable channel branch fan according to the foregoing strategy. When I is greater than the larger value of I0 and I0' and the output current of the photovoltaic power generation system is greater than the sum of the rated currents of the air supply main machine and the exhaust main machine, both the air supply main machine and the exhaust main machine start and control the operation of the variable channel branch fan according to the foregoing strategy.

[0011] In the above technical solution, when the air supply main machine and the exhaust main machine are each driven by the energy output from an independent set of photovoltaic panels, when I < I0 / I < I0', the real-time solar radiation of the photovoltaic panels is small, and the power output by the photovoltaic power generation system is small, which is not sufficient to drive the ventilation main machines (including the air supply main machine and the exhaust main machine) and all variable-channel branch fans (including the variable-channel branch air supply fans and the variable-channel branch exhaust fans) to work simultaneously. Then, by shutting down the ventilation main machines and only starting the fans of the variable-channel branch fans, the fan speed is adjusted according to the actual demand of the air volume (including the air supply volume and the exhaust volume) to achieve the stability of the air volume. When I ≥ I0 / I ≥ I0', the real-time solar radiation of the photovoltaic panels is large, and the power output by the photovoltaic power generation system is large. First, ensure the operation of the air supply main machine / exhaust main machine, and then control the fan and the electric valve to open in an alternative manner according to the magnitude of the inlet pressure of the air supply branch pipe / exhaust branch pipe and the resistance of the air supply branch pipe / exhaust branch pipe. When the inlet pressure of the air supply branch pipe / exhaust branch pipe is large enough to overcome the resistance of the air supply branch pipe / exhaust branch pipe, there is no need to start the fan, but open the electric valve, and regulate the opening degree of the electric valve according to the actual demand of the air volume. When the inlet pressure of the air supply branch pipe / exhaust branch pipe is small and not enough to overcome the resistance of the air supply branch pipe / exhaust branch pipe, close the electric valve, start the fan to increase the residual pressure at the end, and regulate the fan speed according to the actual demand of the air volume to ensure the stability of the air volume. When the air supply main machine and the exhaust main machine are both driven by the energy output from a set of photovoltaic panels, the smaller value of I0 and I0' is preferentially satisfied, and the ventilation main machine corresponding to the smaller value of I0 and I0' is started. When I is greater than the larger value of I0 and I0' and the output current of the photovoltaic power generation system is greater than the sum of the rated currents of the air supply main machine and the exhaust main machine, both the air supply main machine and the exhaust main machine are turned on.

[0012] In a preferred embodiment of the present invention, when the air supply main unit is started, the inlet pressure of the most unfavorable air supply branch pipe far away from the air outlet end of the air supply main unit is compared to see whether it is not less than the resistance of the air supply branch pipe; if it is not less than, the fans of the variable channel branch air supply fans on all the air supply branches are closed, the electric valves are opened, and the electric valve opening is regulated to achieve a stable supply of air volume; if it is less than, the inlet pressure values ​​of each air supply branch pipe are compared to see whether they are greater than the resistance of the air supply branch pipe. If the inlet pressure value of a certain air supply branch pipe is greater than the resistance of the air supply branch pipe, the fan of the variable channel branch air supply fan on the air supply branch pipe is closed, the electric valve is opened, and the electric valve opening is regulated to adjust the air supply volume. If the inlet pressure value of a certain air supply branch pipe is less than or equal to the resistance of the air supply branch pipe, the electric valve in the variable channel branch air supply fan on the air supply branch pipe is closed, the fan is opened, and the fan speed is adjusted to achieve a stable supply of air volume. Stable supply; and / or when the exhaust main unit is started, compare whether the inlet pressure of the most unfavorable exhaust branch pipe farthest from the air inlet end of the exhaust main unit is not less than the resistance of the exhaust branch pipe; if not, close the fans of the variable channel branch exhaust fans on all exhaust branch pipes, open the electric valves, and adjust the opening of the electric valves to achieve stable discharge of air volume; if less than, compare whether the inlet pressure values ​​of each exhaust branch pipe are greater than the resistance of the exhaust branch pipe. If the inlet pressure value of a certain exhaust branch pipe is greater than the resistance of the exhaust branch pipe, close the fan of the variable channel branch exhaust fan on the exhaust branch pipe, open the electric valve, and adjust the opening of the electric valve to adjust the exhaust volume. If the inlet pressure value of a certain exhaust branch pipe is less than or equal to the resistance of the exhaust branch pipe, close the electric valve in the variable channel branch exhaust fan on the exhaust branch pipe, open the fan, and adjust the speed of the fan to achieve stable discharge of air volume.

[0013] The above technical solution provides a way to determine whether all the electric valves of the variable channel branch supply fans / variable channel branch exhaust fans are opened after the air supply main / exhaust main is turned on. Taking into account the resistance of the pipe network, there is pipe resistance loss in the air pressure transported by the air supply main / exhaust main. The farther away from the air supply main outlet end / exhaust main inlet end, the greater the pipe resistance loss. Therefore, when the air supply main / exhaust main is turned on, it is prioritized to determine whether the residual pressure is sufficient to overcome the most unfavorable supply branch pipe / exhaust branch pipe resistance far away from the air supply main outlet end / exhaust main inlet end. If it can be overcome, it indicates that the residual pressure is sufficient to overcome all the resistances of the supply branch pipe / exhaust branch pipe, and there is no need to turn on the fan, and only the electric valve can be opened. Otherwise, the resistances of all the supply branch pipes / exhaust branch pipes cannot be overcome. For those that cannot be overcome, the fan is turned on to increase the pressure, thereby reducing the energy consumption of the ventilation system while achieving stable air volume.

[0014] In a preferred embodiment of the present invention, the control system also stores the solar radiation threshold value I1 of the photovoltaic direct-driven air supply host and / or the solar radiation threshold value I1' of the photovoltaic direct-driven exhaust host, wherein I1 is the minimum solar radiation value that can drive the air supply host to operate and overcome the most unfavorable air supply branch resistance value, and I1' is the minimum solar radiation value that can drive the exhaust host to operate and overcome the most unfavorable exhaust branch resistance value; when I0≤I<I1, the air supply host starts, but the residual pressure is insufficient to overcome all the air supply branch resistances, and the exhaust fan is far away from the air supply host outlet. If the inlet pressure of the air supply branch pipe at the air outlet end is too small to overcome the resistance of the air supply branch pipe, the electric valve in the variable channel branch air supply fan of the air supply branch pipe with the smaller inlet pressure is closed, the fan is turned on, and the fan speed is adjusted to achieve a stable supply of air volume; if the inlet pressure of the air supply branch pipe near the air outlet end of the air supply main unit is large enough to overcome the resistance of the air supply branch pipe, the fan of the variable channel branch air supply fan of the air supply branch pipe with the large inlet pressure is closed, the electric valve is turned on, and the electric valve opening is adjusted to achieve a stable supply of air volume; when I≥I1, the air supply main unit When the fan is started, and the residual pressure is sufficient to overcome the resistance of all air supply branches, the fans of the variable channel branch supply fans of all air supply branches are closed, the electric valves are opened, and the electric valve opening is regulated to achieve a stable supply of air volume; and / or when I0'≤I<I1', the exhaust main unit is started, but the residual pressure is insufficient to overcome the resistance of all exhaust branch pipes, and the inlet pressure of the exhaust branch pipe far away from the air inlet end of the exhaust main unit is too small to overcome the resistance of the exhaust branch pipe, then the electric valve in the variable channel branch exhaust fan of the exhaust branch pipe with the smaller inlet pressure is closed, and the fan is opened to regulate the fan. The speed is adjusted to achieve stable discharge of air volume; if the inlet pressure of the exhaust branch pipe close to the air inlet end of the exhaust main unit is large enough to overcome the resistance of the exhaust branch pipe, the fan of the variable channel branch exhaust fan of the exhaust branch pipe with a large inlet pressure is closed, the electric valve is opened, and the electric valve opening is regulated to achieve stable discharge of air volume; when I≥I1', the exhaust main unit is started, and the residual pressure is sufficient to overcome the resistance of all exhaust branch pipes, the fans of the variable channel branch exhaust fans of all exhaust branch pipes are closed, the electric valve is opened, and the electric valve opening is regulated to achieve stable discharge of air volume.

[0015] The above technical solution provides another way to determine whether all the electric valves of the variable channel branch supply fans / variable channel branch exhaust fans are opened after the air supply main unit / exhaust main unit is turned on. By setting the solar radiation threshold value I1 / I1' in the control system, after the air supply main unit / exhaust main unit is turned on, the size of I is compared with I1 / exhaust main unit. When I≥I1 / I≥I1', it indicates that the residual pressure of the air supply main unit / exhaust main unit is sufficient to overcome the resistance of all air supply branches / exhaust branches, and the fans of the variable channel branch supply fans / variable channel branch exhaust fans of all air supply branches / exhaust branches are closed, and the electric valve is opened; when I<I1 / I<I1', it indicates that the residual pressure of the air supply main unit / exhaust main unit is insufficient to overcome the resistance of all air supply branches / exhaust branches, and it is necessary to compare whether the inlet pressure of each air supply branch / exhaust branch is sufficient to overcome the resistance of the air supply branch / exhaust branch, so as to control the fan and the electric valve to open in one of the ways.

[0016] In a preferred embodiment of the present invention, the method for determining the speed of the variable channel branch blower / variable channel branch exhaust fan is: the residual pressure P required to be provided by the variable channel branch blower is obtained according to the following formula: fan , P fan =ΔP zl -ΔP rk , where ΔP zl The resistance of the supply / exhaust branch pipe under the set air volume Q0, ΔP rk is the static pressure at the inlet of the air supply branch / exhaust branch; the performance relationship between the air pressure and air volume of the fan at the speed n is P = aQ0 2 +bQ0+c, where a, b, and c are known constants; set the air volume Q0 and the residual pressure P that the fan needs to provide. fan Substitute the wind pressure and air volume performance relationship at different speeds of the fan to determine the operating speed of the variable channel branch supply fan / variable channel branch exhaust fan.

[0017] In the above technical solution, whether it is air supply or exhaust, first obtain the set air volume Q0 and the residual pressure P that the fan needs to provide under the set air volume fan , then Q0 and P fan Substitute the wind pressure and air volume performance relationship under different fan speeds into the relationship. When the left and right sides of the relationship are equal or approximately equal, it is determined that the wind pressure and air volume performance relationship is appropriate, and the required fan speed is determined accordingly.

[0018] In another preferred embodiment of the present invention, the resistance ΔP of the air supply branch pipe / exhaust branch pipe under the set air volume Q0 is obtained by the following formula: zl , Where S is the impedance of the supply / exhaust branch pipe.

[0019] The above technical solution adopts the existing relationship between pipeline resistance, pipeline impedance and flow rate. When the pipeline impedance and flow rate are determined, the pipeline resistance, i.e. the resistance ΔP of the air supply branch / exhaust branch, can be calculated. zl .

[0020] In another preferred embodiment of the present invention, the method for determining the opening of the electric valve of the variable channel branch supply fan / variable channel branch exhaust fan is: obtaining the relative difference ΔP between the static pressure at the inlet of the air supply branch pipe / exhaust branch pipe and the outlet of the air supply branch pipe / exhaust branch pipe; obtaining the valve opening f of the electric valve of the variable channel branch supply fan / variable channel branch exhaust fan by the following formula,

[0021]

[0022] Among them, Q0 is the set air volume of the supply air branch pipe / exhaust air branch pipe; Q max The maximum air volume when the pressure difference between the supply air branch pipe and the exhaust air branch pipe is ΔP and the pressure drop in the ventilation duct is 0 and the electric valve is fully open; S V Valve authority is the ratio of the pressure difference before and after the electric valve is fully open to the total pressure difference of the series ventilation duct;

[0023] Among them, obtain valve authority S V Use the following method,

[0024]

[0025] Among them, C gu C is the flow capacity of the ventilation duct connected in series with the electric valve, qk S is the flow capacity of the electric valve when it is fully open. qk is the impedance when the electric valve is fully open, S gu is the impedance of the ventilation duct in series with the electric valve.

[0026] In the above technical solution, whether it is air supply or exhaust, when obtaining the valve opening of the electric valve, the left side of the equation is calculated by setting the air volume Q0 and the maximum air volume Q max The right side of the equation considers the ratio of the pressure difference before and after the electric valve when it is fully open to the total pressure difference of the series ventilation duct, so that the valve opening obtained in this way is more accurate.

[0027] In another preferred embodiment of the present invention, for the set flow rate Q0 of the air supply branch pipe / exhaust branch pipe, when the pressure difference across the air supply branch pipe / exhaust branch pipe is ΔP1, it can be obtained:

[0028]

[0029] Similarly, for the set flow rate Q0 of the supply air branch pipe / exhaust air branch pipe, when the pressure difference across the supply air branch pipe / exhaust air branch pipe is ΔP2, we can obtain:

[0030]

[0031] Among them, Q max1 Q is the maximum air volume when the pressure difference between the supply air branch pipe and the exhaust air branch pipe is ΔP1 and the pressure drop in the ventilation duct is equal to 0 and the electric valve is fully open. max2 The maximum air volume when the pressure difference between the supply air branch pipe and the exhaust air branch pipe is ΔP2 and the pressure drop in the ventilation duct is 0 and the electric valve is fully open, f1 is the first valve opening of the electric valve, and f2 is the second valve opening of the electric valve;

[0032] Combine It can be seen that:

[0033]

[0034] Under the set air volume Q of the supply air branch pipe / exhaust air branch pipe, ΔP1 and the first valve opening f1 of the electric valve can be determined first. In order to ensure that the flow rate remains unchanged, when the pressure difference at both ends of the supply air branch pipe / exhaust air branch pipe changes to ΔP2, the above formula can be used to calculate the second valve opening f2 based on f1 to adjust the valve opening of the electric valve.

[0035] In the above technical solution, whether supplying or exhausting air, the first valve opening f1 of the electric valve is determined when the pressure difference is ΔP1. In order to ensure that the flow rate remains unchanged, when the pressure difference changes to ΔP2, the second valve opening f2 is calculated based on f1 to control the valve opening of the electric valve. Therefore, there is no need to calculate the maximum air volume Q when the pressure difference is ΔP2 and the pressure drop in the ventilation duct is equal to 0 and the electric valve is fully opened. max2 .

[0036] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0038] Figure 1 Schematic diagram of the structure of the photovoltaic-powered distributed ventilation system of Example 1.

[0039] Figure 2 It is a structural diagram of the variable channel branch blower in the embodiment.

[0040] Figure 3 This is a control logic flow chart of the air supply volume stabilization adjustment method in Example 2.

[0041] Figure 4This is a control logic flow chart of the exhaust volume stabilization adjustment method in Example 2.

[0042] Figure 5 It is a schematic diagram of the variable channel branch fan and the ventilation duct in series.

[0043] Figure 6 This is a control logic flow chart of the air supply volume stable adjustment method in Example 3.

[0044] Figure 7 This is a control logic flow chart of the exhaust volume stabilization adjustment method in Example 3.

[0045] The figure marks in the drawings of the specification include: photovoltaic power generation system 1, control system 2, air supply main unit 3, variable channel branch air supply fan 4, casing 41, air inlet 42, air outlet 43, first air circulation path 44, second air circulation path 45, fan 46, electric valve 47, exhaust main unit 5, variable channel branch exhaust fan 6, air supply main pipe 7, air supply branch pipe 8, exhaust main pipe 9, exhaust branch pipe 10, air supply outlet 11, exhaust outlet 12. DETAILED DESCRIPTION

[0046] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0047] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "vertical", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0048] In the description of the present invention, unless otherwise specified and limited, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal communication between two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

[0049] Example 1

[0050] This embodiment provides a photovoltaic-powered distributed ventilation system. Figure 1As shown, in a preferred embodiment, the ventilation system includes a photovoltaic power generation system 1 having photovoltaic panels, a control system 2, and an air supply system for supplying air and / or an exhaust system for exhausting air. Preferably, the air supply system and the exhaust system are set up at the same time.

[0051] The air supply system includes an air supply main unit 3 for supplying air, several variable-channel branch air supply fans 4, and an air supply duct network. The air supply duct network includes an air supply main unit 7 connected to the air outlet 43 of the air supply main unit 3, and several air supply branch pipes 8 connected in parallel to the air outlet of the air supply main unit 7. The air outlet 43 of the air supply branch pipe 8 is connected to the indoor air outlet 11. Each air supply branch pipe 8 is installed with a variable-channel branch air supply fan 4. The exhaust system includes an exhaust main unit 5 for exhausting air, several variable-channel branch exhaust fans 6, and an exhaust duct network. The exhaust duct network includes an exhaust main unit 9 connected to the air inlet of the exhaust main unit 5, and several exhaust branch pipes 10 connected in parallel to the air inlet of the exhaust main unit 9. The air inlet of the exhaust branch pipe 10 is connected to the indoor exhaust outlet 12. The exhaust outlet 12 is relatively far away from the air supply outlet 11. Each exhaust branch pipe 10 is installed with a variable-channel branch exhaust fan 6.

[0052] The air supply main unit 3 and the exhaust main unit 5 are collectively referred to as ventilation main units, and the variable channel branch supply fan 4 and the variable channel branch exhaust fan 6 are collectively referred to as variable channel branch fans.

[0053] The photovoltaic power generation system 1, the air supply main unit 3, several variable channel branch air supply fans 4, the exhaust main unit 5, and several variable channel branch exhaust fans 6 are all connected to the control system 2. The photovoltaic power generation system 1 supplies power to the air supply main unit 3 and / or the exhaust main unit 5. Preferably, the photovoltaic power generation system 1 supplies power to both the air supply main unit 3 and the exhaust main unit 5, and the mains power is used to supply power to several variable channel branch air supply fans 4 and several variable channel branch exhaust fans 6. The air supply main unit 3 and the exhaust main unit 5 are photovoltaic direct-drive devices. The air supply main unit 3 and the exhaust main unit 5 are each driven by the energy output by an independent set of photovoltaic panels (a set of photovoltaic panels includes at least one photovoltaic panel, which can be one or more panels), or the air supply main unit 3 and the exhaust main unit 5 are both driven by the energy output by a set of photovoltaic panels.

[0054] like Figure 2As shown, the variable channel branch blower 4 and the variable channel branch exhaust blower 6 have the same structure. The variable channel branch blower 4 includes a housing 41 having an air inlet 42 and an air outlet 43. Two air circulation paths are arranged in parallel within the housing 41. The two ends of the air circulation paths are connected to the air inlet 42 and the air outlet 43 of the housing 41, respectively. The two air circulation paths are respectively a first air circulation path 44 and a second air circulation path 45. A fan 46 is installed in the first air circulation path 44, and an electric valve 47 is installed in the second air circulation path 45. The fan 46 is a variable speed fan with adjustable speed. The valve opening of the electric valve 47 is adjustable. The air entering the housing 41 is discharged from the air outlet 43 of the housing 41 in a selective manner through one of the air circulation paths. Among them, the fan 46 and the electric valve 47 in the variable channel branch blower 4 are both photovoltaic direct drive devices.

[0055] Photovoltaic power generation system 1 includes a solar radiation sensor (not shown) for detecting the amount of solar radiation emitted by its photovoltaic panels. Inlet pressure sensors (not shown) are provided at the inlets of the supply branch pipe 8 and the exhaust branch pipe 10 for detecting their inlet pressures. Control system 2 controls the operating status of the air supply unit 3, fan 46, and electric valve 47 of the air supply system based on the amount of solar radiation and the inlet pressure of the air supply branch pipe 8. Control system 2 also controls the operating status of the exhaust unit 5, fan 46, and electric valve 47 of the exhaust system based on the amount of solar radiation and the inlet pressure of the exhaust branch pipe 10. Because the output power (primarily output current) of the photovoltaic panels of the photovoltaic power generation system 1 is strongly correlated with the solar radiation intensity (the solar radiation of the photovoltaic panels is positively correlated with the solar radiation intensity), the air volume and pressure of the photovoltaic direct-driven air supply main unit 3 / exhaust main unit 5 are unstable. Therefore, it is necessary to first dynamically control whether the air supply main unit 3 / exhaust main unit 5 is turned on according to the solar radiation intensity, and then adjust the operating status of each variable channel branch fan (including fan 46 and electric valve 47) according to whether the inlet pressure of the air supply branch pipe 8 / exhaust branch pipe 10 can overcome the resistance of the air supply branch pipe 8 / exhaust branch pipe 10. The specific adjustment method is described in Examples 2 and 3 below.

[0056] Example 2

[0057] This embodiment provides a method for stabilizing air volume of a photovoltaic-powered distributed ventilation system based on the first embodiment, so that the air volume delivered into the room through the air supply port 11 and the air volume discharged through the air outlet 12 of the photovoltaic-powered distributed ventilation system are stable.

[0058] The solar radiation sensor detects the real-time solar radiation value I of the photovoltaic panel in real time and transmits it to the control system 2. The control system 2 stores the solar radiation threshold I0 of the air supply host 3 driven directly by photovoltaic and the solar radiation threshold I0' of the exhaust host driven directly by photovoltaic. Here, I0 is the minimum solar radiation value that can drive the air supply host 3 to rotate, and I0' is the minimum solar radiation value that can drive the exhaust host to rotate. I0 is a test value and needs to be calibrated by the manufacturer of the air supply host 3 driven directly by photovoltaic. I0' is also a test value and needs to be calibrated by the manufacturer of the exhaust host 5 driven directly by photovoltaic.

[0059] As Figure 3 and Figure 4 shown, when the air supply host 3 and the exhaust host 5 are each driven by the energy output from an independent set of photovoltaic panels. When I < I0 / I < I0', the control system 2 controls the air supply host 3 / the exhaust host 5 not to start, the electric valves 47 of the air supply fans 4 in each variable channel branch / the exhaust fans 6 in each variable channel branch are closed, and the fans 46 of the air supply fans 4 in each variable channel branch / the exhaust fans 6 in each variable channel branch are started. Each air supply branch 8 / exhaust branch 10 adjusts the speed of the fans 46 of the corresponding air supply fans 4 in the variable channel branch / the exhaust fans 6 in each variable channel branch according to the actual air volume requirements of the corresponding air supply outlets 11 / exhaust outlets 12 (set by the user through the terminal) to achieve stable supply / discharge of the air volume. Since the air supply host 3 / the exhaust host 5 is not started, the inlet pressure of the air supply branch 8 / the exhaust branch 10 is less than or equal to 0 at this time, and the speed control of the fan 46 is required.

[0060] When I ≥ I0 / I ≥ I0', the control system 2 controls the air supply host 3 / the exhaust host 5 to start. According to the inlet pressure of the air supply branch 8 / the exhaust branch 10 where the air supply fans 4 in each variable channel branch / the exhaust fans 6 in each variable channel branch are located (which can be measured by setting an inlet static pressure sensor at the inlet of the air supply branch 8 / the exhaust branch 10) and the resistance of the air supply branch 8 / the exhaust branch 10, the fan 46 and the electric valve 47 are controlled to open in an alternative manner. Each air supply branch 8 / exhaust branch 10 adjusts the opening degree of the electric valve 47 or the speed of the fan 46 according to the actual air volume requirements of the corresponding air supply outlets 11 / exhaust outlets 12 to achieve stable supply / discharge of the air volume.

[0061] It should be noted that when the air supply host 3 and the exhaust host 5 are each driven by the energy output from an independent set of photovoltaic panels, the control of the air supply system and the exhaust system is independent of each other and operates according to the aforementioned strategies respectively.

[0062] In the present invention, when both the air supply host 3 and the exhaust host 5 are driven by the energy output by a set of photovoltaic panels at the same time, the real-time solar radiation value I of the photovoltaic panels of the photovoltaic power generation system 1 preferentially satisfies the smaller value of I0 and I0', and the ventilation host corresponding to the smaller value of I0 and I0' starts and controls the operation of the variable channel branch fan according to the above-mentioned strategy; when I is greater than the larger value of I0 and I0' and the output current of the photovoltaic power generation system 1 is greater than the sum of the rated currents of the air supply host 3 and the exhaust host 5, both the air supply host 3 and the exhaust host 5 start and control the operation of the variable channel branch fan according to the above-mentioned strategy.

[0063] like Figure 3 As shown, specifically, in this embodiment, when the air supply main unit 3 is started, whether the inlet pressure of the most unfavorable air supply branch pipe 8 far away from the air outlet end of the air supply main unit 3 is not less than the resistance of the air supply branch pipe 8; if it is not less than (that is, the inlet pressure of the most unfavorable air supply branch pipe 8 is greater than or equal to the resistance of the air supply branch pipe 8), it indicates that the residual pressure is sufficient to overcome the resistance of all air supply branch pipes 8, then the fans 46 of the variable channel branch blowers 4 on all air supply branch pipes 8 are closed, the electric valve 47 is opened, and the opening degree of the electric valve 47 is regulated to achieve a stable supply of air volume; if it is less than (that is, the inlet pressure of the most unfavorable air supply branch pipe 8 is less than the resistance of the air supply branch pipe 8), it indicates that If the residual pressure is not sufficient to overcome the resistance of all the air supply branch pipes 8, the inlet pressure value of each air supply branch pipe 8 is compared to see whether it is greater than the resistance of the air supply branch pipe 8. If the inlet pressure value of a certain air supply branch pipe 8 is greater than the resistance of the air supply branch pipe 8, the fan 46 of the variable channel branch blower 4 on the air supply branch pipe 8 is closed, and the electric valve 47 is opened, and the opening of the electric valve 47 is regulated to adjust the air supply volume. If the inlet pressure value of a certain air supply branch pipe 8 is less than or equal to the resistance of the air supply branch pipe 8, the electric valve 47 in the variable channel branch blower 4 on the air supply branch pipe 8 is closed, and the fan 46 is opened, and the speed of the fan 46 is adjusted to achieve a stable supply of air volume.

[0064] like Figure 4As shown, specifically, in this embodiment, when the air supply host 5 is started, whether the inlet pressure of the most unfavorable exhaust branch pipe 10 far away from the air inlet end of the exhaust host 5 is not less than the resistance of the exhaust branch pipe 10; if it is not less than (that is, the inlet pressure of the most unfavorable exhaust branch pipe 10 is greater than or equal to the resistance of the exhaust branch pipe 10), it indicates that the residual pressure is sufficient to overcome the resistance of all exhaust branch pipes 10, then the fans 46 of the variable channel branch exhaust fans 6 on all exhaust branch pipes 10 are closed, the electric valve 47 is opened, and the opening degree of the electric valve 47 is regulated to achieve stable discharge of air volume; if it is less than (that is, the inlet pressure of the most unfavorable exhaust branch pipe 10 is less than the resistance of the exhaust branch pipe 10), it indicates that the residual pressure is sufficient to overcome the resistance of all exhaust branch pipes 10. If the pressure is not enough to overcome the resistance of all exhaust branch pipes 10, the inlet pressure value of each exhaust branch pipe 10 is compared to see whether it is greater than the resistance of the exhaust branch pipe 10. If the inlet pressure value of a certain exhaust branch pipe 10 is greater than the resistance of the exhaust branch pipe 10, the fan 46 of the variable channel branch exhaust fan 6 on the exhaust branch pipe 10 is closed, the electric valve 47 is opened, and the opening of the electric valve 47 is regulated to adjust the exhaust volume. If the inlet pressure value of a certain exhaust branch pipe 10 is less than or equal to the resistance of the exhaust branch pipe 10, the electric valve 47 in the variable channel branch exhaust fan 6 on the exhaust branch pipe 10 is closed, the fan 46 is opened, and the speed of the fan 46 is adjusted to achieve stable discharge of air volume.

[0065] In the present invention, when the static pressure at the inlet of the air supply branch pipe 8 is less than or equal to 0 and is insufficient to overcome the resistance of the air supply branch pipe 8, it is necessary to open the fan 46 of the variable channel branch supply fan 4, and adjust the speed of the fan 46 according to the actual air volume demand of the corresponding air supply port 11 to achieve a stable supply of air volume; similarly, when the static pressure at the inlet of the exhaust branch pipe 10 is less than or equal to 0 and is insufficient to overcome the resistance of the exhaust branch pipe 10, it is necessary to open the fan 46 of the variable channel branch exhaust fan 6, and adjust the speed of the fan 46 according to the actual air volume demand of the corresponding exhaust port 12 to achieve a stable discharge of air volume. The specific method for determining the speed of the fan 46 of the variable channel branch supply fan 4 / variable channel branch exhaust fan 6 is:

[0066] First, the residual pressure P that the fan 46 of the variable channel branch supply fan 4 / variable channel branch exhaust fan 6 needs to provide is obtained according to the following formula: fan ,

[0067] P fan =ΔP zl -ΔP rk , (Formula 1)

[0068] Where ΔP zl The resistance of the supply / exhaust branch pipe under the set air volume Q0, ΔP rk The static pressure at the inlet of the air supply branch pipe / exhaust branch pipe can be measured by the inlet static pressure sensor. The resistance ΔP of the air supply branch pipe / exhaust branch pipe under the set air volume Q0 zlThe static pressure at the inlet of the air supply branch / exhaust branch ΔP rk The residual pressure P that the fan 46 of the variable channel branch supply fan / variable channel branch exhaust fan needs to provide fan Two parts of power to overcome, namely ΔP zl =ΔP rk +P fan , we get the above (Formula 1) by transformation. According to the existing relationship between pipe network resistance and flow rate ΔP=SQ0 2 It can be seen that since the supply / exhaust branch pipes do not change, their impedance S remains unchanged (impedance S is only related to the pipe friction coefficient, pipe length, pipe diameter, local resistance coefficient, fluid density, etc. of the supply / exhaust branch pipes, which are determined by the designer when designing the supply / exhaust pipe network and are known). Since the air volume of the supply / exhaust branch pipes needs to be kept stable, the resistance of the supply / exhaust branch pipes under the air volume Q0 is set to In order to keep the air volume of the supply / exhaust branch unchanged, as long as the branch resistance ΔP under the design condition is determined zl , then according to the static pressure ΔP at the inlet of the supply air branch / exhaust air branch rk , you can get the residual pressure P that the fan of the variable channel branch supply fan / variable channel branch exhaust fan needs to provide fan It should be noted that the resistance value of the supply / exhaust branch pipe can also be calculated by the designer in advance during the design process to determine the pipe resistance value at each gear (air volume) for the end user. When the user selects a certain gear (set air volume), the system automatically matches the resistance value of the supply / exhaust branch pipe to the calculated pipe resistance value.

[0069] Secondly, for the air supply system and exhaust system, for example, the air pressure and air volume performance relationship of the fan 46 at the speed n is: Among them, a, b, and c are constants and are known. From this, the performance relationship of wind pressure and air volume at different speeds can be calculated. For example, the performance relationship of wind pressure and air volume at speed n1 is: The performance relationship between wind pressure and air volume at the speed n2 is:

[0070] Then, the air volume Q0 and the residual pressure P that the fan 46 needs to provide are set. fan Substitute the wind pressure and air volume performance relationship of the fan of the supply branch / exhaust branch at different speeds into the relationship. If the left and right sides of the relationship are equal or approximately equal (with allowable residuals), it can be determined that the wind pressure and air volume performance relationship is appropriate, thereby determining the required speed of the fan of the variable channel branch supply fan / variable channel branch exhaust fan, that is, the actual operating speed.

[0071] In the present invention, when the air supply main unit 3 is turned on and the residual pressure is sufficient to overcome the resistance of the air supply branch pipe 8, the fan 46 of the variable channel branch air supply fan 4 is closed and the electric valve 47 is opened. The valve opening of the electric valve 47 is adjusted according to the actual air volume demand of the corresponding air supply port 11 to achieve a stable supply of air volume. Similarly, when the exhaust main unit 5 is turned on and the residual pressure is sufficient to overcome the resistance of the exhaust branch pipe 10, the fan 46 of the variable channel branch air supply fan 6 is closed and the electric valve 47 is opened. The valve opening of the electric valve 47 is adjusted according to the actual air volume demand of the corresponding exhaust port 12 to achieve a stable discharge of air volume. The specific method for determining the electric valve opening of the variable channel branch air supply fan 4 / variable channel branch air supply fan 6 is:

[0072] First, obtain the relative difference ΔP between the static pressure at the inlet of the supply / exhaust branch duct and the outlet of the supply / exhaust branch duct. ΔP is the pressure difference across the supply / exhaust branch duct and is the relative difference between the static pressure at the inlet of the supply / exhaust branch duct and the outlet of the supply / exhaust branch duct. For the supply air system, since the outlet of the supply air branch duct is the end of the air supply, that is, the atmosphere, this value ΔP is the difference between the branch inlet static pressure measured by the inlet static pressure sensor of the supply air branch duct and the ambient atmospheric pressure of the supply air branch duct. For the exhaust air system, this value ΔP is the difference between the branch inlet static pressure measured by the inlet static pressure sensor of the supply air branch duct and the branch outlet static pressure measured by the outlet static pressure sensor of the supply air branch duct.

[0073] Secondly, the valve opening f of the electric valve of the variable channel branch supply fan / variable channel branch exhaust fan is obtained by the following formula:

[0074]

[0075] Among them, f refers to the degree of opening of the electric valve, usually measured in angle or stroke; Q0 is the set air volume of the supply air branch / exhaust air branch, which is set by the user at the terminal; Q max Q is the maximum air volume when the pressure difference between the supply air branch pipe and the exhaust air branch pipe is ΔP and the pressure drop in the ventilation duct is equal to 0 and the electric valve is fully open. max The air volume can be obtained by testing the air volume when the electric valve is fully open at different inlet pressures of the air supply branch pipe / exhaust branch pipe. The technical specifications provided by the electric valve manufacturer are known values, such as Figure 5 As shown, the ventilation duct refers to all pipes and air supply / air outlet components on the air supply branch / exhaust branch except the variable channel branch air supply fan / variable channel branch exhaust fan. The ventilation duct is in series with the electric valve; S V The valve authority is the ratio of the pressure difference before and after the electric valve is fully opened to the total pressure difference of the series ventilation duct.

[0076] Combine Figure 5 As shown, obtain the valve authority S V Use the following method,

[0077]

[0078] Among them, C gu C is the flow capacity of the ventilation duct connected in series with the electric valve, qk S is the flow capacity of the electric valve when it is fully open. qk is the impedance when the electric valve is fully open, S gu The impedance of the ventilation duct connected in series with the electric valve. qk , the impedance value S of the ventilation duct connected in series gu It has been determined when the air supply branch is designed (the electric valve and air supply branch are selected), so the valve authority S V It is always a fixed value during the valve opening adjustment process of the electric valve.

[0079] For a certain air supply branch / exhaust branch, the pressure difference at both ends changes with the change of the photovoltaic direct-driven air supply main unit / exhaust main unit. That is, when the electric valve of the air supply branch / exhaust branch is opened, the pressure difference at both ends of the air supply branch / exhaust branch where the electric valve is located changes. At this time, for the set flow Q0 of the air supply branch / exhaust branch, when the pressure difference at both ends of the air supply branch / exhaust branch is ΔP1, it can be seen from the above formula 2 that the relative flow (the ratio of the set flow to the maximum flow) is:

[0080]

[0081] Among them, Q max1 It is the maximum air volume when the pressure difference between the two ends of the supply air branch pipe / exhaust air branch pipe is ΔP1 and the pressure drop in the ventilation duct is equal to 0, and the electric valve is fully open. f1 is the first valve opening of the electric valve.

[0082] Similarly, when the pressure difference between the supply and exhaust branches is ΔP2, the relative flow rate (the ratio of the set flow rate to the maximum flow rate) is:

[0083]

[0084] Among them, Q max2 It is the maximum air volume when the pressure difference between the two ends of the supply air branch pipe / exhaust air branch pipe is ΔP2 and the pressure drop in the ventilation duct is equal to 0 and the electric valve is fully open. f2 is the second valve opening of the electric valve.

[0085] Obviously, under different pressure differences between the two ends of the air supply branch pipe and the exhaust branch pipe (i.e., different ΔP), the maximum flow rate Q max is different, while the impedance S of the electric valve at its maximum opening is constant. get:

[0086]

[0087] Based on this, according to Formula 5, dividing Formula 3 and Formula 4 yields:

[0088]

[0089] ΔP1 and ΔP2 in Equation 6 can be detected by sensors. At the set air volume Q0 of the supply / exhaust branch pipe, when the pressure difference across the supply / exhaust branch pipe is ΔP1, the first valve opening f1 of the electric valve can be determined according to Equation 3. To ensure that the flow rate remains unchanged, when the pressure difference across the supply / exhaust branch pipe changes to ΔP2, the second valve opening f2 can be calculated using Equation 6 to control the valve opening of the electric valve. This eliminates the need to calculate the maximum air volume Q when the pressure difference across the supply / exhaust branch pipe is ΔP2 and the pressure drop in the ventilation duct is 0, and the electric valve is fully open. max2 .

[0090] Example 3

[0091] The structure and principle of this embodiment are basically the same as those of embodiment 2. The difference is that after the air supply main unit 3 / exhaust main unit 5 is turned on, the method for determining whether the variable channel branch air supply fan 4 / variable channel branch exhaust fan 6 have all opened the electric valve 47 is different. The rest is the same as embodiment 2.

[0092] Specifically, if Figure 6 and Figure 7 As shown, in this embodiment, the control system 2 also stores the solar radiation threshold value I1 of the photovoltaic direct-driven air supply host 3 and the solar radiation threshold value I1' of the photovoltaic direct-driven exhaust host 5, wherein I1 is the minimum solar radiation value that can drive the air supply host 3 to operate and overcome the most unfavorable resistance value of the air supply branch 8, and I1' is the minimum solar radiation value that can drive the exhaust host 5 to operate and overcome the most unfavorable resistance value of the exhaust branch 10. Among them, the most unfavorable supply air branch pipe resistance value / the most unfavorable exhaust air branch pipe resistance value can be calculated by the designer using professional hydraulic software when designing the supply air network / exhaust air network, and is known; the supply air host / exhaust air host manufacturer can also determine the supply air host / exhaust air host rotation outlet pressure value under each solar radiation. When selecting the supply air host / exhaust air host, the designer matches the appropriate supply air host / exhaust air host according to the most unfavorable loop resistance value calculated by hydraulics. The ventilation system is initially designed before it is put into operation, and tested during the installation and adjustment stage of the ventilation system to obtain accurate values, which are then entered into the ventilation system for comparison.

[0093] like Figure 6As shown, when I0≤I<I1, the air supply main unit 3 is started, but the residual pressure is not enough to overcome the resistance of all the air supply branch pipes 8. The inlet pressure of the air supply branch pipe 8 far away from the air outlet end of the air supply main unit 3 is relatively small and is not enough to overcome the resistance of the air supply branch pipe 8. Then, the electric valve 47 in the variable channel branch air supply fan 4 where the air supply branch pipe 8 with a relatively small inlet pressure is located is closed, and the fan 46 is turned on. The speed of the fan 46 is adjusted to achieve a stable supply of air volume; if the inlet pressure of the air supply branch pipe 8 close to the air outlet end of the air supply main unit 3 is large enough to overcome the resistance of the air supply branch pipe 8, then the fan 46 of the variable channel branch air supply fan 4 where the air supply branch pipe 8 with a sufficiently large inlet pressure is located is closed, and the electric valve 47 is turned on. The opening of the electric valve 47 is regulated to achieve a stable supply of air volume.

[0094] When I≥I1, the air supply main unit 3 starts, and the residual pressure is sufficient to overcome the resistance of all air supply branch pipes 8. Then the fans 46 of the variable channel branch air supply fans 4 of all air supply branch pipes 8 are closed, and the electric valve 47 is opened to adjust the opening of the electric valve 47 to achieve a stable supply of air volume.

[0095] like Figure 7 As shown, when I0'≤I<I1', the exhaust main unit 5 is started, but the residual pressure is not enough to overcome the resistance of all exhaust branch pipes 10. The inlet pressure of the exhaust branch pipe 10 far away from the air inlet end of the exhaust main unit 5 is small and insufficient to overcome the resistance of the exhaust branch pipe 10, then the electric valve 47 in the variable channel branch exhaust fan 6 where the exhaust branch pipe 10 with a small inlet pressure is located is closed, the fan 46 is turned on, and the speed of the fan 46 is adjusted to achieve stable discharge of air volume; the inlet pressure of the exhaust branch pipe 10 close to the air inlet end of the exhaust main unit 5 is large enough to overcome the resistance of the exhaust branch pipe 10, then the fan 46 of the variable channel branch exhaust fan 6 where the exhaust branch pipe 10 with a sufficiently large inlet pressure is located is closed, the electric valve 47 is turned on, and the opening of the electric valve 47 is adjusted to achieve stable discharge of air volume.

[0096] When I≥I1', the exhaust main unit 5 starts, and the residual pressure is sufficient to overcome the resistance of all exhaust branch pipes 10, then the fans 46 of the variable channel branch exhaust fans 6 of all exhaust branch pipes 10 are closed, and the electric valve 47 is opened to adjust the opening of the electric valve 47 to achieve stable discharge of air volume.

[0097] The present invention solves the problem that due to changes in light, the output power of the photovoltaic power generation system 1 changes, which causes changes in the outlet pressure of the photovoltaic direct-driven air supply main unit 3, so that the air supply volume of each air supply branch pipe 8 cannot be stably supplied to each room at the terminal. It also solves the problem that due to changes in light, the output power of the photovoltaic power generation system 1 changes, which causes changes in the inlet pressure of the photovoltaic direct-driven exhaust main unit 5, so that the exhaust volume of each room at the terminal cannot be stably discharged. When there is sufficient sunlight, the outlet pressure of the photovoltaic direct-driven air supply main unit 3 is sufficient to overcome the resistance of the air supply main and the air supply branch pipes connected to each room, and the inlet pressure of the photovoltaic direct-driven exhaust main unit 5 is sufficient to overcome the resistance of the exhaust main and the exhaust branch pipes connected to each room, but the inlet pressure of each supply air branch pipe 8 / exhaust branch pipe 10 is different. At this time, the valve opening of the electric valve can be adjusted to adjust the inlet pressure of the electric valve; but when there is insufficient sunlight or at night, the terminal variable channel branch supply fan 4 / variable channel branch exhaust fan 6 still needs to use the building's own AC power (i.e., mains power). At this time, the inlet pressure of each supply air branch pipe 8 / exhaust branch pipe 10 is also different. At this time, it is necessary to adjust the fan speed of the variable channel branch supply fan 4 / variable channel branch exhaust fan 6 to ensure the stability of the air supply and exhaust volume in each room at the end.

[0098] Throughout this specification, reference to terms such as "preferred embodiment," "one embodiment," "some embodiments," "example," "specific example," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0099] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. Photovoltaic powered distributed ventilation system, characterized in that: It includes a photovoltaic power generation system, a control system, and an air supply system for supplying air and / or an air exhaust system for exhausting air; The air supply system includes an air supply main unit for supplying air, a plurality of variable channel branch air supply units, and an air supply pipe network. The air supply pipe network includes an air supply main unit connected to the air outlet of the air supply main unit, and a plurality of air supply branches connected in parallel to the air outlet of the air supply main unit. The air outlets of the air supply branches are connected to the indoor air outlets. Each air supply branch pipe is equipped with a variable channel branch air supply unit. The exhaust system includes an exhaust main unit for exhausting air, a plurality of variable channel branch exhaust fans, and an exhaust pipe network. The exhaust pipe network includes an exhaust main unit connected to the air inlet of the exhaust main unit, and a plurality of exhaust branch pipes connected in parallel to the air inlet of the exhaust main unit. The air inlet of the exhaust branch pipe is connected to the indoor exhaust outlet. Each exhaust branch pipe is equipped with a variable channel branch exhaust fan. The photovoltaic power generation system, the air supply main unit, several variable channel branch air supply fans, the exhaust main unit, and several variable channel branch exhaust fans are all connected to the control system. The photovoltaic power generation system supplies power to the air supply main unit and / or the exhaust main unit, and the mains electricity supplies power to the several variable channel branch air supply fans and / or several variable channel branch exhaust fans. The air supply main unit and / or the exhaust main unit are photovoltaic direct-drive devices. The air supply main unit and the exhaust main unit are collectively referred to as ventilation main units, and the variable channel branch air supply fans and variable channel branch exhaust fans are collectively referred to as variable channel branch fans; The variable channel branch fans each include a housing having an air inlet and an air outlet, wherein two air circulation paths arranged in parallel are provided in the housing, and fans and electric valves are respectively installed in the two air circulation paths, wherein the fans are variable speed fans with adjustable speed, and the opening of the electric valves is adjustable, and the air entering the housing is discharged from the air outlet of the housing in a selective manner through one of the air circulation paths; The photovoltaic power generation system has a solar radiation sensor for detecting the solar radiation of its photovoltaic panels, and an inlet pressure sensor for detecting the inlet pressure of the air supply branch pipe and / or the exhaust branch pipe is provided at the inlet thereof; The control system controls the operating status of the air supply main unit, fan and electric valve of the air supply system according to the solar radiation amount and the inlet pressure of the air supply branch pipe; and / or the control system controls the operating status of the exhaust main unit, fan and electric valve of the exhaust system according to the solar radiation amount and the inlet pressure of the exhaust branch pipe.

2. A method for stabilizing air volume in a photovoltaic-powered distributed ventilation system according to claim 1, characterized in that: The solar radiation sensor detects the real-time solar radiation value I of the photovoltaic panel in real time and transmits it to the control system, and the control system stores the solar radiation threshold value I0 of the photovoltaic direct-driven air supply host and / or the solar radiation threshold value I0' of the photovoltaic direct-driven exhaust host, where I0 is the minimum solar radiation value that can drive the air supply host to rotate, and I0' is the minimum solar radiation value that can drive the exhaust host to rotate; When both the air supply main unit and the exhaust main unit are photovoltaic direct-drive devices, the air supply main unit and the exhaust main unit are each driven by energy output by an independent set of photovoltaic panels, or both the air supply main unit and the exhaust main unit are simultaneously driven by energy output by a set of photovoltaic panels; When the air supply main machine and the exhaust main machine are each driven by the energy output from an independent set of photovoltaic panels, when I < I0 / I < I0', the control system controls the air supply main machine / exhaust main machine not to start, closes the electric valves of the air supply fans of each variable channel branch / the exhaust fans of each variable channel branch, starts the fans of the air supply fans of each variable channel branch / the exhaust fans of each variable channel branch, and adjusts the fan speeds of the corresponding variable channel branch air supply fans / the exhaust fans of each variable channel branch according to the actual air volume requirements of the corresponding air supply outlets / exhaust outlets to achieve stable air volume; when I ≥ I0 / I ≥ I0', the control system controls the air supply main machine / exhaust main machine to start, and controls the fan and the electric valve to open in an alternative manner according to the magnitude of the inlet pressure of the air supply branch / exhaust branch where the air supply fans of each variable channel branch / the exhaust fans of each variable channel branch are located and the resistance of the air supply branch / exhaust branch. Each air supply branch / each exhaust branch adjusts the opening degree of the electric valve or the fan speed according to the actual air volume requirements of the corresponding air supply outlets / exhaust outlets to achieve stable air volume; When the air supply main machine and the exhaust main machine are both driven by the energy output from a set of photovoltaic panels, the solar real-time radiation quantity value I of the photovoltaic panels of the photovoltaic power generation system preferentially satisfies the smaller value of I0 and I0'. The ventilation main machine corresponding to the smaller value of I0 and I0' starts and controls the operation of the variable channel branch fans according to the strategy when I < I0 / I < I0' described above; when I is greater than the larger value of I0 and I0' and the output current of the photovoltaic power generation system is greater than the sum of the rated currents of the air supply main machine and the exhaust main machine, both the air supply main machine and the exhaust main machine start and control the operation of the variable channel branch fans according to the strategy when I ≥ I0 / I ≥ I0' described above.

3. The air volume stable adjustment method according to claim 2, wherein: When the air supply main machine starts, compare whether the inlet pressure of the most unfavorable air supply branch far from the outlet end of the air supply main machine is not less than the resistance of this air supply branch; if it is not less than, then close the fans of the variable channel branch air supply fans on all air supply branches, open the electric valves, and adjust the opening degree of the electric valves to achieve stable air volume supply; if it is less, then compare whether the inlet pressure value of each air supply branch is greater than the resistance of this air supply branch. If the inlet pressure value of a certain air supply branch is greater than the resistance of this air supply branch, then close the fan of the variable channel branch air supply fan on this air supply branch, open the electric valve, and adjust the opening degree of the electric valve to adjust the air supply volume. If the inlet pressure value of a certain air supply branch is less than or equal to the resistance of this air supply branch, then close the electric valve in the variable channel branch air supply fan on this air supply branch, open the fan, and adjust the fan speed to achieve stable air volume supply; And / or when the exhaust main unit is started, compare whether the inlet pressure of the most unfavorable exhaust branch pipe farthest from the air inlet end of the exhaust main unit is not less than the resistance of the exhaust branch pipe; if it is not less than, close the fans of the variable channel branch exhaust fans on all exhaust branch pipes, open the electric valves, and adjust the opening of the electric valves to achieve stable discharge of air volume; if it is less than, compare whether the inlet pressure values ​​of each exhaust branch pipe are greater than the resistance of the exhaust branch pipe. If the inlet pressure value of a certain exhaust branch pipe is greater than the resistance of the exhaust branch pipe, close the fan of the variable channel branch exhaust fan on the exhaust branch pipe, open the electric valve, and adjust the opening of the electric valve to adjust the exhaust volume. If the inlet pressure value of a certain exhaust branch pipe is less than or equal to the resistance of the exhaust branch pipe, close the electric valve in the variable channel branch exhaust fan on the exhaust branch pipe, open the fan, and adjust the speed of the fan to achieve stable discharge of air volume.

4. The method for stabilizing air volume according to claim 2, wherein: The control system also stores a solar radiation threshold value I1 of the photovoltaic direct-driven air supply host and / or a solar radiation threshold value I1' of the photovoltaic direct-driven exhaust host, wherein I1 is the minimum solar radiation value that can drive the air supply host to operate and overcome the most unfavorable air supply branch pipe resistance value, and I1' is the minimum solar radiation value that can drive the exhaust host to operate and overcome the most unfavorable exhaust branch pipe resistance value; When I0≤I<I1, the air supply main unit starts, but the residual pressure is insufficient to overcome the resistance of all air supply branch pipes, and the inlet pressure of the air supply branch pipe far away from the air outlet end of the air supply main unit is insufficient to overcome the resistance of the air supply branch pipe, then the electric valve in the variable channel branch air supply fan of the air supply branch pipe where the inlet pressure is insufficient to overcome the resistance of the air supply branch pipe is closed, the fan is turned on, and the speed of the fan is adjusted to achieve a stable supply of air volume; if the inlet pressure of the air supply branch pipe close to the air outlet end of the air supply main unit can overcome the resistance of the air supply branch pipe, then the fan of the variable channel branch air supply fan of the air supply branch pipe where the inlet pressure can overcome the resistance of the air supply branch pipe is closed, the electric valve is opened, and the opening of the electric valve is regulated to achieve a stable supply of air volume; when I≥I1, the air supply main unit starts, and the residual pressure is sufficient to overcome the resistance of all air supply branch pipes, then the fans of the variable channel branch air supply fans of all air supply branch pipes are closed, the electric valve is opened, and the opening of the electric valve is regulated to achieve a stable supply of air volume; And / or when I0'≤I<I1', the exhaust main unit starts, but the residual pressure is insufficient to overcome the resistance of all exhaust branch pipes, and the inlet pressure of the exhaust branch pipe far away from the air inlet end of the exhaust main unit is insufficient to overcome the resistance of the exhaust branch pipe, then the electric valve in the variable channel branch exhaust fan of the exhaust branch pipe where the inlet pressure is insufficient to overcome the resistance of the supply air branch pipe is closed, the fan is turned on, and the speed of the fan is adjusted to achieve stable discharge of air volume; if the inlet pressure of the exhaust branch pipe close to the air inlet end of the exhaust main unit can overcome the resistance of the exhaust branch pipe, then the fan of the variable channel branch exhaust fan of the exhaust branch pipe where the inlet pressure can overcome the resistance of the supply air branch pipe is closed, the electric valve is opened, and the opening of the electric valve is adjusted to achieve stable discharge of air volume; when I≥I1', the exhaust main unit starts, and the residual pressure is sufficient to overcome the resistance of all exhaust branch pipes, then the fans of the variable channel branch exhaust fans of all exhaust branch pipes are closed, the electric valve is opened, and the opening of the electric valve is adjusted to achieve stable discharge of air volume.

5. The method for stabilizing air volume according to claim 3 or 4, characterized in that: The method for determining the fan speed of the variable channel branch supply fan / variable channel branch exhaust fan is: The residual pressure P that the fan of the variable channel branch supply fan / variable channel branch exhaust fan needs to provide is obtained according to the following formula fan P fan =ΔP zl -ΔP rk Where ΔP zl The resistance of the supply / exhaust branch pipe under the set air volume Q0, ΔP rk The static pressure at the inlet of the supply / exhaust branch pipe; The performance relationship between the fan's wind pressure and air volume at the speed n is: Among them, a, b, and c are constants and are known; Set the air volume Q0 and the residual pressure P that the fan needs to provide fan Substitute the wind pressure and air volume performance relationship at different speeds of the fan to determine the operating speed of the variable channel branch supply fan / variable channel branch exhaust fan.

6. The method for stabilizing air volume according to claim 5, characterized in that: The resistance ΔP of the supply air branch / exhaust air branch under the set air volume Q0 is obtained by the following formula zl , Where S is the impedance of the supply / exhaust branch pipe.

7. The method for stabilizing air volume according to any one of claims 3 or 4, characterized in that: The method for determining the opening of the electric valve of the variable channel branch supply fan / variable channel branch exhaust fan is: Obtain the relative difference ΔP between the static pressure at the inlet of the supply air branch / exhaust air branch and the static pressure at the outlet of the supply air branch / exhaust air branch; The valve opening f of the electric valve of the variable channel branch supply fan / variable channel branch exhaust fan is obtained by the following formula: Among them, Q0 is the set air volume of the supply air branch pipe / exhaust air branch pipe; Q max The maximum air volume when the pressure difference between the supply air branch pipe and the exhaust air branch pipe is ΔP and the pressure drop in the ventilation duct is 0 and the electric valve is fully open; S V Valve authority is the ratio of the pressure difference before and after the electric valve is fully open to the total pressure difference of the series ventilation duct; Among them, obtain valve authority S V Use the following method, Among them, C gu C is the flow capacity of the ventilation duct connected in series with the electric valve, qk S is the flow capacity of the electric valve when it is fully open. qk is the impedance when the electric valve is fully open, S gu is the impedance of the ventilation duct in series with the electric valve.

8. The method for stabilizing air volume according to claim 7, characterized in that: For the set flow rate Q0 of the air supply branch pipe / exhaust branch pipe, when the pressure difference between the two ends of the air supply branch pipe / exhaust branch pipe is ΔP1, we get: Similarly, for the set flow rate Q0 of the air supply branch pipe / exhaust branch pipe, when the pressure difference between the two ends of the air supply branch pipe / exhaust branch pipe is ΔP2, we get: Among them, Q max1 Q is the maximum air volume when the pressure difference between the supply air branch pipe and the exhaust air branch pipe is ΔP1 and the pressure drop in the ventilation duct is equal to 0 and the electric valve is fully open. max2 The maximum air volume when the pressure difference between the supply air branch pipe and the exhaust air branch pipe is ΔP2 and the pipe pressure drop is 0 and the electric valve is fully open, f1 is the first valve opening of the electric valve, and f2 is the second valve opening of the electric valve; Combine It can be seen that: Under the set air volume Q0 of the supply / exhaust branch pipe, ΔP1 and the first valve opening f1 of the electric valve are first determined. To ensure that the flow rate remains unchanged, when the pressure difference across the supply / exhaust branch pipe changes to ΔP2, the above formula is used to calculate the second valve opening f2 based on f1 to control the valve opening of the electric valve.

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