Heating, ventilation and air conditioning system, control method of heating, ventilation and air conditioning system, and computer readable storage medium

Abstract

The invention provides a heating, ventilation and air conditioning system, a control method of the heating, ventilation and air conditioning system and a computer readable storage medium. The heating, ventilation and air conditioning system comprises a refrigeration / heat pump unit, an air processing unit and a controller. And the refrigeration / heat pump unit provides working fluid. The air processing unit is provided with a heat exchanger, air exchanges heat with working fluid flowing through the heat exchanger and then supplies air to the indoor space, and the air processing unit adjusts the air supply temperature of air supplied to the indoor space based on the temperature set point. And a controller configured to obtain an expected emission level of an energy source to power the HVAC system, and adjust the temperature setpoint based on the expected emission level.

Description

Technical Field

[0001] The present application relates to the field of HVAC, and in particular to a HVAC system, a control method for a HVAC system, and a computer-readable storage medium. Background Art

[0002] A building's primary electrical energy consumption comes from its HVAC systems. Conventional HVAC system control methods aim to reduce electricity consumption by maintaining the system's set temperature within a specific range during operating hours and shutting it down during off-hours. However, reducing electricity consumption may not necessarily translate into efficient use of electricity. Summary of the Invention

[0003] The present application aims to provide a HVAC system, a control method for the HVAC system, and a computer-readable storage medium, so as to at least solve or alleviate some of the problems existing in the prior art.

[0004] In a first aspect, the present application provides a heating, ventilation, and air conditioning (HVAC) system comprising a refrigeration / heat pump unit, an air handling unit, and a controller. The refrigeration / heat pump unit provides a working fluid. The air handling unit includes a heat exchanger. Air exchanges heat with the working fluid flowing through the heat exchanger and is then supplied to a room. The air handling unit adjusts the supply air temperature to the room based on a temperature set point. The controller is configured to obtain an expected emission level of energy used to power the HVAC system and adjust the temperature set point based on the expected emission level.

[0005] In an optional technical solution, the HVAC system controller is configured to adjust the temperature set point in a manner that reduces input power to the HVAC system when the emission level is expected to increase.

[0006] In an alternative HVAC system, when expected emission levels indicate that the energy source will be relatively dirty, the temperature set point is increased for a period of time in cooling mode and decreased for a period of time in heating mode.

[0007] In an optional technical solution, the controller is configured to adjust the temperature set point in a manner that increases the input power to the HVAC system when the emission level is expected to decrease.

[0008] In an alternative HVAC system, when expected emissions levels indicate that the energy source will be relatively cleaner, the temperature set point is lowered for a period of time in cooling mode and raised for a period of time in heating mode.

[0009] In the HVAC system of the optional technical solution, the temperature set point is increased or decreased by a larger amount than is actually needed at the time.

[0010] In the HVAC system of an optional technical solution, the controller is further configured to: obtain at least one parameter associated with thermal comfort, determine whether the at least one parameter satisfies a preset constraint, and based on the determination, select whether to adjust the temperature set point based on the expected emission level.

[0011] A second aspect of the present application provides a control method for a HVAC system, the control method comprising the following steps: obtaining an expected emission level of energy that will power the HVAC system; and adjusting a temperature set point based on the expected emission level.

[0012] In the control method of the HVAC system of the optional technical solution, the following steps are further included: in response to the step of "adjusting the temperature set point based on the expected emission level", adjusting the flow rate or supply temperature of the working fluid

[0013] In the control method of the HVAC system of an optional technical solution, the air handling unit also includes an external air inlet and a circulating air inlet, a first damper is provided at the corresponding external air inlet, and a second damper is provided at the corresponding circulating air inlet, and the control method also includes the following steps: in response to the step of "adjusting the temperature set point based on the expected emission level", adjusting the opening of the first damper and / or the second damper.

[0014] In the control method of the HVAC system of the optional technical solution, in the step of "adjusting the temperature set point based on the expected emission level", the input power of the HVAC system is reduced when the expected emission level increases; and the input power of the HVAC system is increased when the expected emission level decreases.

[0015] In the control method of the HVAC system of the optional technical solution, in the step of "adjusting the temperature set point based on the expected emission level", when the expected emission level indicates that the energy will become relatively dirty, the temperature set point is increased for a period of time in the cooling mode, and the temperature set point is decreased for a period of time in the heating mode; when the expected emission level indicates that the energy will become relatively clean, the temperature set point is decreased for a period of time in the cooling mode, and the temperature set point is increased for a period of time in the heating mode.

[0016] In the control method of the HVAC system of the optional technical solution, in the step of "adjusting the temperature set point based on the expected emission level", the increase / decrease range of the temperature set point is greater than the change range actually required at the time.

[0017] In the control method of the HVAC system of the optional technical solution, the following steps are also included: obtaining at least one parameter associated with thermal comfort, judging whether the at least one parameter satisfies a preset constraint, and selecting whether to execute the step of "adjusting the temperature set point based on the expected emission level" based on the judgment.

[0018] In an alternative method for controlling a heating, ventilation, and air conditioning system, the at least one parameter includes a difference between an actual temperature within a building and a desired temperature within the building. A preset constraint condition is that the difference is greater than a threshold. When the difference is greater than the threshold, the step of "adjusting the temperature set point based on the expected emission level" is not performed. When the difference is less than the threshold, the step of "adjusting the temperature set point based on the expected emission level" is performed.

[0019] A third aspect of the present application provides a computer-readable storage medium storing a control program, which, when executed by a processor, implements the control method of the HVAC system in any of the above-mentioned optional technical solutions.

[0020] According to the HVAC system, the control method of the HVAC system, and the computer-readable storage medium of the air-conditioning system of the present application, the HVAC system can use electricity more reasonably. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of an air handling unit according to an embodiment of the present application is shown;

[0022] Figure 2 A schematic diagram showing the change of MOER over time according to an embodiment of the present application is shown;

[0023] Figure 3 A schematic diagram showing a HVAC system operating in a cooling mode according to an embodiment of the present application is shown;

[0024] Figure 4 A schematic diagram showing a HVAC system operating in a heating mode according to an embodiment of the present application is shown;

[0025] Figure 5 A schematic diagram showing a HVAC system operating in a cooling mode according to an embodiment of the present application is shown;

[0026] Figure 6 A schematic diagram of a model predictive control system according to an embodiment of the present application is shown;

[0027] Figure 7 shows a control flow chart according to an embodiment of the present application;

[0028] Figure 8 A control flow chart according to an embodiment of the present application is shown.

[0029] Figure numerals: air handling unit 10, supply air handling unit 1, heat exchanger 12, supply air fan 13, external air inlet 14, circulating air inlet 15, first air damper 16, second air damper 17, temperature sensor 18, return air handling unit 2, return air fan 23, exhaust outlet 24, channel 3, controller 19, model predictive control system 200. DETAILED DESCRIPTION

[0030] First of all, it should be noted that the following will illustrate the composition, working principle, characteristics and advantages of the HVAC system, the control method of the HVAC system, and the computer-readable storage medium according to the present application in an illustrative manner, but it should be understood that all descriptions are given for illustration only and should not be understood as forming any limitation on the present application.

[0031] In addition, for any single technical feature described or implied in the embodiments mentioned in this document, or any single technical feature shown or implied in the accompanying drawings, this application still allows for continued arbitrary combination or deletion between these technical features (or their equivalents) without any technical obstacles, thereby obtaining more other embodiments of the present application that may not be directly mentioned in this document.

[0032] <HVAC System>

[0033] The HVAC system in the embodiment of the present application is used in a building and includes a refrigeration / heat pump unit (not shown) and an air handling unit 10. The refrigeration / heat pump unit is used to provide a working fluid, such as water or a refrigerant. The air handling unit 10 has a heat exchanger 12. Air exchanges heat with the working fluid flowing through the heat exchanger 12 before being delivered to the indoor space. The air handling unit 10 adjusts the supply air temperature to the indoor space based on a temperature set point.

[0034] In one embodiment, Figure 1 As shown, the air handling unit 10 includes a supply air handling unit 1 and a return air handling unit 2 , and a channel 3 is located between the supply air handling unit 1 and the return air handling unit 2 .

[0035] Two heat exchangers 12 and an air supply fan 13 are provided in the air supply treatment unit 1. Cold water from the refrigeration unit flows through the coil of one of the heat exchangers 12 to provide cooling for the air to be treated. Hot water from the heat pump unit flows through the coil of the other heat exchanger 12 to provide heat for the air to be treated. Based on whether the HVAC unit chooses to operate in cooling mode or heating mode, only one of the refrigeration unit and the heat pump unit and its corresponding heat exchanger 12 can be operated, and the other and its corresponding heat exchanger 12 can be not operated. Of course, the refrigeration unit and the heating unit and their corresponding heat exchangers 12 can also be put into operation as needed. A return air fan 23 is provided in the return air treatment unit 2. The air to be treated can be outside air, or a mixture of outside air and circulating air.

[0036] Part of the return air entering the return air handling unit 2 exits through the exhaust port 24, while the remaining portion passes through the duct 3 as recirculating air and enters the supply air handling unit 1 through the recirculating air inlet 15. The outside air entering through the outside air inlet 14 and the recirculating air entering through the recirculating air inlet 15 mix and pass through the heat exchanger 12 before being delivered indoors. The term "indoors" here refers to the interior of a building.

[0037] A first damper 16 is provided at the corresponding external air inlet 14, and a second damper 17 is provided at the corresponding circulating air inlet 15. The ratio of external air and circulating air entering the air supply treatment unit 1 can be adjusted by adjusting the opening of the first damper 16 and the opening of the second damper 17.

[0038] The temperature of the supply air should meet the temperature set point. A temperature sensor 18 can be used to detect the temperature of the supply air.

[0039] It should be understood that the refrigeration / heat pump unit and the air handling unit 10 can be arranged inside or outside the building.

[0040] It should be understood that the locations of the heat exchangers 12, fans, and inlets and outlets in the air handling unit 10 are not limited to those shown in the figure. The air handling unit 10 can be in various forms, such as a dedicated outside air system (DOAS), an air handling unit 10 with a variable air volume unit (VAV), or an air handling unit 10 with a fan coil unit (FCU). A separate variable air volume unit (VAV) or fan coil unit (FCU) is also within the scope of the air handling unit 10 of the present application.

[0041] The HVAC system in the embodiment of the present application further includes a controller 19 configured to obtain an expected emission level of an energy source that will provide power to the HVAC system and adjust a temperature set point based on the expected emission level.

[0042] Producing electricity requires energy, which can be fossil fuels or renewable clean energy sources like wind, solar, and nuclear power. Generally speaking, when clean energy accounts for a higher proportion of the energy consumed to generate electricity, energy emissions are lower; when clean energy accounts for a lower proportion, energy emissions are higher.

[0043] The expected emission level is a forecast of the emission levels of the energy source that powers the HVAC system over a period of time in the future. The "period of time in the future" can be long or short, with no specific limitations. In some embodiments, the period of time in the future is within the next half hour. In some embodiments, the period of time in the future is within the next 10 minutes.

[0044] Expected emission levels can be used to guide electricity usage. When expected emission levels increase, it is hoped that electricity consumption (or input power) can be appropriately reduced. When expected emission levels decrease, electricity consumption (or input power) can be appropriately increased. In this way, the cooling / heating load of the HVAC system can be shifted.

[0045] By adjusting the supply air temperature set point, you can alter the power consumption of the HVAC system. For example, in cooling mode, increasing the temperature set point can reduce the demand for the working fluid flow to the chiller, or increase the supply temperature to improve chiller efficiency, thereby reducing the chiller's power consumption.

[0046] According to the HVAC system of the embodiment of the present application, the purpose of reducing emissions can be achieved by adjusting the temperature set point of the supply air in the air handling unit 10 in real time based on the expected emission level.

[0047] As an example, if the proportion of clean energy is predicted to decrease and the expected emission level increases during period t, the temperature set point can be adjusted to reduce the demand for working fluid in the refrigeration / heat pump unit compared to the current period, thereby reducing the emissions during period t by reducing the electricity consumption during period t. If the proportion of clean energy is predicted to increase and the expected emission level decreases during period t, more cooling / heating can be obtained by adjusting the temperature set point. This cooling / heating can be stored in the building's materials (such as the building's walls) and released during the period when the proportion of clean energy decreases, utilizing the building's thermal inertia to meet the thermal comfort needs of the building's occupants.

[0048] In some embodiments, emission level predictions are performed by inputting a grid carbon emission index (MOER) provided by a third-party data provider.

[0049] Figure 2This is a diagram showing how MOER changes over time. It is understood that within a day and in different seasons, the power grid will rely on renewable energy or green energy (clean energy) as much as possible, but will also rely on fossil fuels (dirty energy) to a certain extent. For example, as renewable energy or green energy, wind energy, nuclear energy or solar energy can be used as a substitute for fossil fuels. However, the proportion of clean energy will change with the availability of wind energy, nuclear energy and solar energy. Figure 2 As shown in the figure, X is the emission at midnight, which is relatively high. Y is the emission at noon the next day, which is lower. The emission at Z is higher again.

[0050] like Figure 2 As shown by the dotted line I in FIG, the curve changes according to different dates, seasons or weather conditions. In other words, the curve does not simply change periodically at different times of the day.

[0051] like Figure 3 As shown, the MOER curve 40 shows a "dirty" spike at 42. The temperature setpoint curve 48 is raised to 49 to reduce the use of relatively dirty energy. When passing through 42, the temperature setpoint is controlled to be lowered at 50 to help the temperature in the building recover. When the temperature setpoint is lowered, the temperature setpoint change can be larger than the actual change required at the time. When the MOER returns to its normal value at 43, the temperature setpoint is returned to the actual required level at 51. In this way, the overall emissions of the HVAC system can be reduced. Although the reduction may not be large, even a small reduction in emissions can be valuable over time.

[0052] It should be understood that there is thermal inertia in the HVAC system, or in the building, so even if the temperature set point is increased at 49, the building will not immediately become overheated. In addition, the increase at 49 does not need to be large.

[0053] It should be understood that Figure 3 Schematic diagram of the HVAC system operating in cooling mode. At the same time, the power variation line 44 drops at 46 to coincide with the peak 42.

[0054] Figure 4 This is a schematic diagram of an HVAC system operating in heating mode. When a spike 42 occurs, the temperature setpoint variation line 48 drops to 60 and then increases to 62. When the MOER returns to its normal level 43, or when the temperature inside the building becomes unacceptable, the temperature setpoint is raised to 62 to quickly restore the building temperature. Then, after a period of time, the temperature setpoint is lowered from 62 to the actual desired temperature 63.

[0055] Furthermore, it can be seen that the power variation line 44 drops at 46 to coincide with the peak 42 , and rises at 64 .

[0056] Figure 5 One possible scenario is shown in FIG. 1 . In this scenario, the MOER variation line 40 has a long-duration spike 42. The temperature setpoint variation line 48 rises for a period of time at 149, then falls at 150, and moves back and forth between 149 and 150 until it returns to the actual desired level at 151. In this way, when a long-duration spike is expected, thermal comfort is not significantly reduced when the temperature inside the building is acceptable.

[0057] It should be understood that Figure 5 Operation in cooling mode is shown, the same may occur in heating mode.

[0058] Figure 6 is a schematic diagram of a model predictive control system. Output information 202 enters the HVAC system controller 19. Predictor 204 receives MOER information 206. Predictor 204 also receives output information 202 and is able to predict carbon emissions and the room temperature to be experienced in the building. Input information 216 may be a reference temperature for the building. Cost function 210 and constraints 212 are provided to optimizer 208. Constraints 212 may include, for example, limits on the range and duration of temperature deviations from a desired temperature. Model predictive control system 200 also provides a building site or model 214.

[0059] Although the model predictive control system 200 is shown here separately from the controller 19 , it may of course be integrated into the controller 19 .

[0060] Model predictive control system 200 can calculate carbon emissions savings based on the methods and apparatus of the present application. As an example, the predicted emissions per British thermal unit of energy, combined with the BTUs reduced during each reduction period, can be used to derive the carbon emissions savings achieved by the present method. These savings can be reported to various organizations that recognize carbon emissions savings. While the basic algorithm for calculating carbon emissions savings is described above, more sophisticated algorithms can be developed.

[0061] <Control Method of HVAC System>

[0062] The control method of the HVAC system in the embodiment of the present application includes the following steps: obtaining an expected emission level of energy that will provide power to the HVAC system; and adjusting a temperature set point based on the expected emission level.

[0063] Figure 7A control flow diagram for cooling mode is shown, which increases the temperature set point for a period of time when expected emission levels indicate that the energy source will be relatively dirty, and decreases the temperature set point for a period of time when expected emission levels indicate that the energy source will be relatively clean.

[0064] A method for determining whether the expected emission level indicates that the energy will become relatively dirty, and a method for determining whether the expected emission level indicates that the energy will become relatively clean, can be implemented, for example, by comparing the current emission level with the expected emission level, or by discovering whether the MOER curve has a "dirty" peak or a "clean" peak.

[0065] Similar to the control method in cooling mode, in heating mode, when the expected emission level indicates that the energy source will be relatively dirty, the temperature set point is lowered for a period of time, and when the expected emission level indicates that the energy source will be relatively clean, the temperature set point is raised for a period of time.

[0066] In some embodiments, the control method further includes the following steps: obtaining at least one parameter associated with thermal comfort, determining whether the at least one parameter satisfies a preset constraint, and selecting whether to perform the step of "adjusting the temperature set point based on the expected emission level" based on the determination.

[0067] refer to Figure 8 When at least one parameter does not meet the preset constraints, the temperature set point is adjusted in the emission reduction mode, that is, the temperature set point is adjusted based on the expected emission level. When at least one parameter does not meet the preset constraints, the temperature set point is adjusted in the normal mode, that is, the temperature set point is adjusted based on the actual temperature demand in the building.

[0068] In some embodiments, the at least one parameter includes a difference between an actual temperature within the building and a desired temperature within the building. A preset constraint condition is that the difference is greater than a threshold. When the difference is greater than the threshold, the step of "adjusting the temperature set point based on the expected emission level" is not performed; when the difference is less than the threshold, the step of "adjusting the temperature set point based on the expected emission level" is performed.

[0069] In some embodiments, the flow rate or supply temperature of the working fluid is adjusted in response to the "adjusting the temperature set point based on expected emission levels" step. That is, when the temperature set point of the supply air in the air handling unit 10 changes, the flow rate or temperature of the working fluid provided by the refrigeration / heat pump unit will change accordingly. Since refrigeration / heat pump units often have high power consumption, adjusting the demand for working fluid can quickly achieve the desired change in power consumption, thereby aligning power changes as closely as possible with "dirty" or "clean" peaks.

[0070] In some embodiments, in response to the step of "adjusting the temperature set point based on the expected emission level," the opening degree of the first damper 16 and / or the second damper 17 is adjusted. By adjusting the opening degree of the first damper 16 and / or the second damper 17, the proportion of recirculated air in the treated air can be increased when necessary to maintain a certain degree of thermal comfort in the building.

[0071] It should be understood that responding to "adjusting the temperature set point based on the expected emission level" is not limited to adjusting the temperature of the working fluid, the opening of the first damper 16 and / or the second damper 17. For example, the supply fan 13 or the return air fan 23 may also be adjusted.

[0072] In some embodiments, in the step of “adjusting the temperature set point based on the expected emission level”, the input power to the HVAC system is reduced when the expected emission level increases; and the input power to the HVAC system is increased when the expected emission level decreases.

[0073] In some embodiments, during the step of "adjusting the temperature set point based on the expected emission level," the temperature set point is increased / decreased by a greater amount than is actually required at the time.

[0074] <Computer-readable storage medium>

[0075] According to the computer-readable storage medium in the embodiments of the present application, a control program is stored. When the control program is executed by a processor, the control method of the HVAC system introduced in some of the above embodiments is implemented.

[0076] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A heating, ventilation and air conditioning system, characterized in that: include: Refrigeration / heat pump unit, providing working fluid; an air handling unit having a heat exchanger, wherein air exchanges heat with the working fluid flowing through the heat exchanger and then is supplied to the room, and the air handling unit adjusts the supply air temperature to the room based on a temperature set point; A controller is configured to obtain an expected emissions level of energy that will power the HVAC system and adjust the temperature set point based on the expected emissions level.

2. The HVAC system according to claim 1, wherein: The controller is configured to adjust the temperature set point in a manner that reduces input power to the HVAC system when the expected emission level increases.

3. The HVAC system according to claim 2, wherein: When the expected emission levels indicate that the energy source will be relatively dirty, In cooling mode, the temperature set point is raised for a period of time, In heating mode, the temperature set point is lowered for a period of time.

4. The HVAC system according to claim 1, wherein: The controller is configured to adjust the temperature set point in a manner that increases input power to the HVAC system when the expected emission level decreases.

5. The HVAC system according to claim 4, wherein: When the expected emission levels indicate that the energy source will be relatively cleaner, In cooling mode, the temperature set point is lowered for a period of time. In heating mode, the temperature set point is increased for a period of time.

6. The HVAC system according to claim 3 or 5, characterized in that: The temperature set point is increased / decreased by a greater amount than is actually required at the time.

7. The HVAC system according to any one of claims 1 to 5, characterized in that: The controller is further configured to obtain at least one parameter associated with thermal comfort, determine whether the at least one parameter satisfies a preset constraint, and select whether to adjust the temperature set point based on the expected emission level based on the determination.

8. A method for controlling a heating, ventilation and air conditioning system, characterized in that: The HVAC system includes: Refrigeration / heat pump unit, providing working fluid; an air handling unit having a heat exchanger, wherein air exchanges heat with the working fluid flowing through the heat exchanger and then is supplied to the room, and the air handling unit adjusts the supply air temperature to the room based on a temperature set point; The control method comprises the following steps: Obtaining expected emission levels for the energy that will power said HVAC system; The temperature set point is adjusted based on the expected emission level.

9. The method for controlling a heating, ventilation and air conditioning system according to claim 8, wherein: The following steps are also included: In response to the step of "adjusting the temperature set point based on the expected emission level", the flow rate or supply temperature of the working fluid is adjusted.

10. The method for controlling a heating, ventilation and air conditioning system according to claim 9, wherein: The air handling unit further comprises an external air inlet and a circulating air inlet, a first damper is provided at the external air inlet, and a second damper is provided at the circulating air inlet. The control method further comprises the following steps: In response to the step of “adjusting the temperature set point based on the expected emission level”, the opening of the first damper and / or the second damper is adjusted.

11. The method for controlling a heating, ventilation and air conditioning system according to claim 8, wherein: In the step of "adjusting the temperature set point based on the expected emission level", reducing input power to the HVAC system when the expected emission level increases; The input power to the HVAC system is increased when the expected emission level decreases.

12. The method for controlling a heating, ventilation and air conditioning system according to claim 8, wherein: In the step of "adjusting the temperature set point based on the expected emission level", When the expected emission level indicates that the energy source will become relatively dirty, increasing the temperature set point for a period of time in cooling mode and decreasing the temperature set point for a period of time in heating mode; When the expected emission levels indicate that the energy source will be relatively cleaner, the temperature set point is lowered for a period of time in cooling mode and the temperature set point is raised for a period of time in heating mode.

13. The method for controlling a heating, ventilation and air conditioning system according to claim 8, wherein: In the step of "adjusting the temperature set point based on the expected emission level", the temperature set point is increased / decreased by a greater amount than is actually required at the time.

14. The method for controlling a heating, ventilation and air conditioning system according to claim 8, wherein: The following steps are also included: Obtain at least one parameter associated with thermal comfort, determine whether the at least one parameter satisfies a preset constraint, and select whether to perform the step of "adjusting the temperature set point based on the expected emission level" based on the determination.

15. The control method of the HVAC system according to claim 14, characterized in that: The at least one parameter includes a difference between an actual temperature within the building and a desired temperature within the building; The preset constraint condition is that the difference is greater than a threshold; When the difference is greater than a threshold, choosing not to perform the step of “adjusting the temperature set point based on the expected emission level”; When the difference is less than a threshold, the step of adjusting the temperature set point based on the expected emission level is selected for execution.

16. A computer-readable storage medium storing processor-readable instructions, characterized in that: When the processor-readable instructions are executed by the processor, the method for controlling the HVAC system according to any one of claims 8 to 15 is implemented.

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