Modular heat pump unit system

Abstract

This invention relates to a heat pump unit system, and more particularly to the control of the start-up energy demand of the heat pump unit system. The system corrects the full-load temperature difference using ambient temperature and water flow rate. It determines the number of energy supply units required at the current moment by calculating the ratio of the current temperature difference to the corrected full-load temperature difference. Furthermore, it monitors whether the actual energy output of the started energy supply units meets the actual energy demand by comparing the real-time total system outlet temperature with the system's total set outlet temperature, and determines whether to exit the start-up energy demand control mode accordingly. This system effectively solves the problems of long loading times caused by full-load heat pump units and frequent start-ups and shutdowns due to the mismatch between the start-up energy supply and the actual energy demand.

Description

Technical Field

[0001] This invention relates to the field of heat pumps, and more particularly to a modular heat pump unit system. Background Technology

[0002] For applications with high hot water consumption, such as heated swimming pools, bathhouses, hotels, schools, and dormitories, hot water boilers or multi-module combined heat pump water heaters are mainly used in engineering to provide large quantities of hot water. Hot water boilers convert chemical energy into thermal energy by burning fuel to provide users with a large amount of hot water, but their efficiency is relatively low, and installation is limited under increasingly stringent environmental protection conditions. Existing multi-module combined heat pump water heaters meet environmental protection requirements and have relatively high energy efficiency, making them increasingly popular among users with high hot water consumption. However, currently installed multi-module combined heat pump systems are set to load each module and its energy supply unit sequentially upon startup, resulting in slow loading speed and delayed heating, affecting the user experience. For example, in a 4-module heat pump system, with each module containing 16 energy supply units and each energy supply unit having a 40-second adjustment time, starting up all 64 energy supply units of the modular heat pump system would take more than 42 minutes. Existing multi-module heat pump unit systems have excessively long loading times. When the system prepares hot water in winter, all power supply units have just finished loading when the first unit to start needs to sequentially enter the defrost cycle to cool the water, causing abnormal fluctuations in water temperature. Furthermore, because the start-up control of multi-module heat pump unit systems is set to operate with all power supply units on, when the actual energy output after all power supply units have finished loading far exceeds the actual energy demand, there is a need to immediately unload the loaded power supply units, resulting in frequent start-ups and shutdowns and significant water temperature fluctuations.

[0003] In summary, the existing start-up control methods for multi-module joint operation heat pump unit systems have long loading times and result in frequent fluctuations in the temperature of the produced hot water, which affects the user experience. Summary of the Invention

[0004] Based on this, the purpose of the present invention is to provide a modular heat pump unit system, which includes a method for controlling the number of heat pump units to start and stop when the system is started. This method can effectively solve the problems of long loading time caused by fully running heat pump units and frequent start-up and shutdown of units due to mismatch between the energy supplied by the heat pump units and the actual energy demand.

[0005] A modular heat pump unit system includes: several independent energy supply units, a water circuit module, a temperature acquisition module, and a controller electrically and / or communicatively connected to the energy supply units, water circuit module, and temperature acquisition module; the several independent energy supply units are connected in parallel via the water circuit module; the heat pump unit system enters an energy demand control mode upon startup.

[0006] The controller acquires the total outlet water set temperature of the heat pump unit system, the pre-stored full-open temperature difference data, and the initial state data transmitted by the water circuit module and the temperature acquisition module. It then corrects the pre-stored full-open temperature difference data based on the initial state data to obtain the full-open temperature difference at the current moment.

[0007] The controller calculates the required temperature difference at the current moment based on the total outlet water set temperature and the total inlet water temperature transmitted by the temperature acquisition module. It also calculates the required number of power supply units at the current moment based on the required temperature difference, the full-open temperature difference, and the total number of power supply units. The controller then starts the corresponding number of power supply units according to the preset power supply unit start rules and controls the started power supply units to run to the target frequency.

[0008] The controller controls the power supply unit to operate at the target frequency, and acquires the total system outlet water temperature collected by the temperature acquisition module in real time, comparing the total system outlet water temperature with the set total system outlet water temperature.

[0009] If the total outlet water temperature of the system is lower than the total outlet water temperature of the system, the power supply unit that is controlled to start will continue to operate at the target frequency and acquire the total outlet water temperature of the system in real time.

[0010] If the total system outlet water temperature is greater than or equal to the total system outlet water set temperature, then exit the start-up energy demand control mode.

[0011] Compared to existing technologies, this invention, through a method designed to control the start-up and shutdown of each heat pump unit in the system according to actual needs, can control the loading of each energy supply unit according to actual energy demand, ensuring that the actual output energy matches the actual energy demand. This control method shortens the loading time of the entire energy supply cycle, effectively avoiding the problem of abnormal water temperature fluctuations caused by the earlier-loaded energy supply units entering defrost mode due to excessively long loading time, thus improving the user's energy consumption experience. Simultaneously, this control method matches the actual output energy with the actual energy demand, effectively avoiding the problem of frequent start-up and shutdown of energy supply units caused by the need for immediate load reduction after all energy supply units are fully operational, thus extending the compressor's service life.

[0012] Furthermore, the current fully open temperature difference satisfies the following formula:

[0013]

[0014] in, This indicates the temperature difference at the current moment when it is fully open. This indicates that the pre-stored full-open temperature difference is stored. This indicates the impact of water flow deviation on the temperature difference at the current fully open position; α is the water flow deviation influence factor. It is a pre-stored full-open temperature difference value The corresponding rated water flow rate, It is the current water flow rate; This represents the impact of ambient temperature difference on the current fully open temperature difference, where β is the ambient temperature difference influence factor, and R is the normal adjustment value set by the environment in which the heat pump unit system is located. It is the ambient temperature at the current moment.

[0015] Furthermore, the required temperature difference at the current moment satisfies the following formula:

[0016]

[0017] in: This indicates the current temperature difference required. This indicates the system's total outlet water set temperature. This indicates the current total inlet water temperature of the system.

[0018] Furthermore, the number of power supply units required at the current moment satisfies the following formula:

[0019]

[0020] Where, N R This indicates the number of energy supply units required at the current moment. This indicates the current temperature difference required. N represents the temperature difference at the current moment when the circuit is fully open. total This indicates the total number of energy supply units contained in the heat pump unit system.

[0021] To better understand and implement this invention, the following detailed description is provided in conjunction with the accompanying drawings. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a heat pump unit system according to an embodiment of the present invention;

[0023] Figure 2 This is a flowchart illustrating the start-up energy demand control process of a heat pump unit system according to an embodiment of the present invention. Detailed Implementation

[0024] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings of the embodiments of the present invention.

[0025] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that, unless otherwise stated, “a plurality” means two or more; and the term “and / or” as used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0026] In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. In the description of this application, it should be understood that the terms "first," "second," "third," etc., are used only for distinction and not to describe a specific order or sequence, nor should they be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0027] To address the problem of frequent start-up and shutdown of power supply units in existing modular heat pump systems when the actual output energy far exceeds the actual energy demand, resulting in significant water temperature fluctuations, this invention, after research and debugging, designs a method for controlling the number of heat pump units to start and stop during system startup. This method determines the number of power supply units that need to be activated by calculating the ratio of the actual demand temperature difference to the corrected full-load temperature difference, thus matching the number of activated power supply units with the actual energy demand, improving energy efficiency and user experience. Simultaneously, by activating power supply units in an orderly manner according to established rules, the lifespan of the power supply units is extended.

[0028] The method for controlling the number of heat pump units to start and stop in the modular heat pump unit system designed in this invention is applicable to the following situations:

[0029] (1) When the actual control temperature of the system reaches or exceeds the set temperature, all energy units stop, and the water temperature in the buffer tank drops below the set threshold, the power supply unit is restarted.

[0030] (2) When the system changes from the shutdown state to the power-on state.

[0031] Please see Figure 1The modular heat pump unit system proposed in this invention includes n independent power supply modules 10 (n≥2), a water circuit module 20, a temperature acquisition module 30, and a controller (not shown in the figure); the n independent power supply modules 10 are connected in parallel through the water circuit module 20; the n independent power supply modules 10, the water circuit module 20, and the temperature acquisition module 30 are electrically connected and / or communication connected to the controller, respectively.

[0032] In specific implementation, when the energy supply module 10 includes m independent heat pump units 11 (m≥2), each heat pump unit 11 is an energy supply unit, and the modular heat pump unit system includes n×m energy supply units. Each heat pump unit 11 includes a compressor 112, a four-way valve (not shown), a condenser (not shown), an expansion valve (not shown), an evaporator (not shown), and a fan (not shown). The compressor 112, four-way valve, condenser, expansion valve, and evaporator are sequentially connected via refrigerant piping; the compressor 112, four-way valve, expansion valve, and fan are electrically and / or communicatively connected to the controller; the m condensers of the m independent heat pump units 11 are connected in parallel via a water circuit module 10.

[0033] When the energy supply module 10 includes m compressors, a four-way valve (not shown), a condenser (not shown), an expansion valve (not shown), an evaporator (not shown), and a fan (not shown), the energy supply module 10 is an energy supply unit. In this case, the modular heat pump unit system includes n energy supply units. The m compressors share the same fan, the same evaporator, and the same condenser. The m compressors, four-way valve, condenser, expansion valve, and evaporator are sequentially connected via refrigerant piping. The m compressors, four-way valve, expansion valve, and fan are electrically and / or communicatively connected to the controller. The condensers of the n energy supply modules 10 are connected in parallel via a water circuit module 10.

[0034] The water circuit module 20 includes an inlet pipe 21, an outlet pipe 22, a water flow meter 23, a water pump assembly 24, and a buffer tank 25. The inlet pipe 21 includes a main system inlet pipe 210 and module branch inlet pipes 212. The main system inlet pipe 210 is divided into n module branch inlet pipes 212, each connected to the water circuit of one of the n power supply modules 10. The outlet pipe 22 includes a main system outlet pipe 220 and module outlet inlet pipes 222. The main system outlet pipe 220 is divided into n module branch inlet pipes 222, each connected to the water circuit of one of the n power supply modules 10.

[0035] The water flow meter 23 is installed on the main water inlet pipe 210 of the system to measure the total water inlet volume of the system and is electrically and / or communicatively connected to the controller.

[0036] The water pump assembly 24 is installed on the system's main water inlet pipe 210 and is used to provide a constant water supply for the modular heat pump unit system.

[0037] The buffer tank 25 is equipped with an inlet A connected to the system's main inlet pipe 210, an outlet B connected to the system's main outlet pipe 220, a return outlet C connected to an external water source and external water return pipe, and a supply outlet D connected to an external water pipe. The buffer tank serves as a buffer between the heat pump unit system and the user's water consumption, and can, to a certain extent, prevent sudden changes in the inlet water temperature of the heat pump unit system caused by changes in the user's heat demand.

[0038] The temperature acquisition module 30 includes a first temperature sensor 31, a second temperature sensor 32, and a third temperature sensor 33. The first temperature sensor 31 is used to measure the ambient temperature signal; the second temperature sensor 32 is installed on the system's main water inlet pipe 210 to measure the temperature signal of the system's main water inlet; the third temperature sensor 33 is installed on the system's main water outlet pipe 220 to measure the temperature signal of the system's main water outlet; the first temperature sensor 31, the second temperature sensor 32, and the third temperature sensor 33 transmit the measured temperature signals to the controller.

[0039] Furthermore, inlet water temperature sensors can be installed on the inlet water pipes 212 of each module to measure the temperature signal of the water entering each module and transmit the measured signal to the controller; outlet water temperature sensors can be installed on the outlet water pipes 222 of each module to measure the temperature signal of the water exiting each module and transmit the measured signal to the controller.

[0040] The controller receives measurement signals from the temperature acquisition module 30 and the water flow meter 23, and sends start / stop signals to the heat pump unit 11 via a control program stored on the controller. The controller also includes a storage unit for storing historical measurement data, including pre-stored full-start temperature differences of the heat pump unit system upon initial startup. The data table shows the full-opening temperature difference during the first startup. For all power supply modules and all power supply units under rated power and rated water flow rate The difference between the total outlet water temperature and the total inlet water temperature of the system was measured under different ambient temperatures without defrosting.

[0041] When the heat pump unit system is started, the controller calculates the start-up energy demand based on the received data and controls the number, time and sequence of start-up and shutdown of the energy supply units accordingly, which includes the following steps.

[0042] S10 obtains the total outlet water set temperature of the heat pump unit system. The system pre-stores the full-open temperature difference data, the initial state data transmitted by the water circuit module and the temperature acquisition module, and corrects the pre-stored full-open temperature difference data based on the initial state data to obtain the full-open temperature difference at the current moment.

[0043] Specifically, it includes the following sub-steps:

[0044] S11 obtains the total outlet water set temperature of the heat pump unit system. Pre-stored full-open temperature difference data, current ambient temperature Current water flow rate and the current total inlet water temperature of the system

[0045] The controller obtains the user-preset total system outlet water temperature based on the system startup command. The system includes pre-stored full-load temperature difference data. The start-up command includes commands issued by the user to the modular heat pump unit system based on heating and water supply needs, or commands issued by a user-defined timed start-up program; this application does not impose specific limitations. The pre-stored full-load temperature difference data is a table of full-load temperature difference data for the first start-up of the heat pump unit system, pre-stored in the controller's storage unit.

[0046] At the same time, the controller receives the ambient temperature measured by the first temperature sensor 31 at the current moment. The second temperature sensor 32 measures the current total inlet water temperature of the system. The current flow rate measured by the water flow meter 23

[0047] S12 sets the temperature according to the total effluent temperature of the system. and the ambient temperature at the current moment The corresponding full-opening temperature difference is obtained by querying the pre-stored full-opening temperature difference data.

[0048] This invention provides an example table of temperature difference data for a modular heat pump unit system in heating or hot water production mode when fully open, as shown in Table 1. The value of the temperature difference when fully open is determined based on the total outlet water set temperature and the ambient temperature.

[0049] Table 1. Temperature difference data at full opening

[0050] Unit: ℃

[0051]

[0052]

[0053] S13 Based on the current ambient temperature and the current water flow rate According to equation (1), the fully open temperature difference Make corrections to obtain the temperature difference at the current fully open position.

[0054]

[0055] in, This indicates the impact of water flow deviation on the temperature difference at the current fully open position; α is the water flow deviation influence factor. It is a pre-stored full-open temperature difference value The corresponding rated water flow rate, It is the current water flow rate; This represents the impact of ambient temperature difference on the current fully open temperature difference, where β is the ambient temperature difference influence factor, and R is the normal adjustment value set according to the environment in which the heat pump unit system is located. It is the ambient temperature at the current moment, and the range of the corrected normal quantity is (5~9).

[0056] S20 sets the temperature according to the total effluent temperature of the system. The current total inlet water temperature of the system is transmitted to the temperature acquisition module. The required temperature difference at the current moment is calculated. And based on the current temperature difference requirement Current moment, full temperature difference Total number of power supply units N total The number N of power supply units required at the current moment is calculated. R It starts the corresponding number of power supply units according to the preset power supply unit start rules, and controls the started power supply units to run to the target frequency.

[0057] In practice, the controller obtains the number of power supply units required by the system at the current moment through the following sub-steps, and controls the corresponding number of power supply units to start operation.

[0058] S21 sets the temperature according to the total effluent temperature of the system. and the current total inlet water temperature of the system The required temperature difference at the current moment is calculated according to equation (2).

[0059]

[0060] S22 requires temperature difference based on the current time. Current moment, full temperature difference And the total number of power supply units N total The number of energy supply units N required at the current moment can be calculated according to equation (3). R .

[0061]

[0062] When the heat pump unit 11 includes an independent fan system, the modular heat pump unit system includes n×m energy supply units, i.e., N total =n×m; When m compressors share one fan system, the modular heat pump unit system includes n energy supply units, i.e., N total =n.

[0063] S23 starts the corresponding number of power supply units according to the preset power supply unit start-up rules, and controls the started power supply units to run to the target frequency.

[0064] Specifically, in the preset energy supply unit start-up rules, there are no restrictions on which energy supply modules 10 or heat pump units 11 are activated, as long as the number of activated energy supply modules 10 or heat pump units 11 is equal to the number N of energy supply units required at the current moment. R The order of operation is not limited. When selecting to start the power supply module 10 or heat pump unit 11, the historical operating time, failure rate, and number of faulty units of each power supply unit can be comprehensively considered when sending start commands. The power supply module 10 or heat pump unit 11 with a relatively short operating time can be started to ensure that the operating time of all units is as similar as possible; or the power supply module 10 or heat pump unit 11 with no faults or a small number of faulty units can be started to ensure operational stability and accuracy. After determining the number of power supply units required for the current start-up and which power supply modules 10 or heat pump units 11 to be started, the controller does not restrict the start-up order sent to the power supply modules 10 or heat pump units 11 to be started. They can be started sequentially or simultaneously. For users with limited circuit overload, sequential start-up is allowed, with a start-up interval of 3-8 seconds to effectively shorten the start-up time and ensure heating effect. For users with high circuit overload, simultaneous start-up can be used to effectively ensure heating effect.

[0065] The power supply unit, started by S30 control, operates at the target frequency and acquires the total system outlet water temperature in real time from the temperature acquisition module. The total outlet water temperature of the system With the total effluent set temperature of the system Comparison:

[0066] If the total outlet water temperature of the system Less than the system's total outlet water set temperature The power supply unit that is controlled to start will continue to operate at the target frequency and obtain the total outlet water temperature of the system in real time;

[0067] If the total outlet water temperature of the system Greater than or equal to the system's total outlet water set temperature Then exit the power-on energy demand control mode.

[0068] Specifically, the controller monitors whether the energy actually output by the activated power supply unit meets the actual energy demand through the following sub-steps, and makes a judgment on whether to exit the start-up energy demand control mode accordingly.

[0069] The power supply unit, controlled by S31, operates at the target frequency and acquires the total system outlet water temperature in real time.

[0070] The total outlet water temperature of the system The temperature is collected by the third temperature sensor 33 and sent to the controller.

[0071] S32 compares the total outlet water temperature of the system. Is it less than the total outlet water set temperature of the system?

[0072] If the total outlet water temperature of the system Less than the system's total outlet water set temperature Then proceed to step S31;

[0073] If the total outlet water temperature of the system Greater than or equal to the system's total outlet water set temperature Then proceed to step S33.

[0074] Among them, the total outlet water temperature of the system is obtained. The application does not impose any restrictions on the interval time. A reasonable acquisition time interval can be set according to the ambient temperature and the capacity of the buffer tank, such as 5-10 minutes.

[0075] S33 exits the power-on energy demand control mode.

[0076] The modular heat pump unit system provided by this invention corrects the full-open temperature difference by using ambient temperature and water flow rate. It determines the number of energy supply units that need to be started based on the ratio of the actual required temperature difference to the corrected full-open temperature difference, and starts the energy supply units according to the energy supply unit start-up rules. By comparing the real-time total system outlet water temperature with the system total outlet water set temperature, it monitors whether the actual output energy of the started energy supply units meets the actual required energy, ensuring that the started energy supply units meet the actual energy demand and avoiding the problem of the actual output energy being much greater than the actual required energy when all energy supply units are loaded.

[0077] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and the present invention also intends to include these modifications and variations.

Claims

1. A modular heat pump unit system, comprising several independent energy supply units, a water circuit module, a temperature acquisition module, and a controller electrically and / or communicatively connected to the energy supply units, the water circuit module, and the temperature acquisition module; wherein the several independent energy supply units are connected in parallel via the water circuit module; characterized in that, The heat pump unit system enters the start-up energy demand control mode upon startup: The controller acquires the total outlet water set temperature of the heat pump unit system, the pre-stored full-open temperature difference data, and the initial state data transmitted by the water circuit module and the temperature acquisition module. It then corrects the pre-stored full-open temperature difference data based on the initial state data to obtain the full-open temperature difference at the current moment. The controller calculates the required temperature difference at the current moment based on the total outlet water set temperature and the total inlet water temperature transmitted by the temperature acquisition module. It also calculates the required number of power supply units at the current moment based on the required temperature difference, the full-open temperature difference, and the total number of power supply units. The controller then starts the corresponding number of power supply units according to the preset power supply unit start rules and controls the started power supply units to run to the target frequency. The controller controls the power supply unit to operate at the target frequency, and acquires the total system outlet water temperature collected by the temperature acquisition module in real time, comparing the total system outlet water temperature with the set total system outlet water temperature. If the total outlet water temperature of the system is lower than the total outlet water temperature of the system, the power supply unit that is controlled to start will continue to operate at the target frequency and acquire the total outlet water temperature of the system in real time. If the total system outlet water temperature is greater than or equal to the total system outlet water set temperature, then exit the start-up energy demand control mode.

2. The heat pump unit system according to claim 1, characterized in that, The initial state data includes the ambient temperature measured by the temperature acquisition module and the water flow rate transmitted by the water circuit module. The controller determines the corresponding fully open temperature difference from the pre-stored fully open temperature difference data based on the total outlet water set temperature of the system and the ambient temperature at the current moment, and corrects the fully open temperature difference based on the ambient temperature and the water flow rate at the current moment to obtain the fully open temperature difference at the current moment.

3. The heat pump unit system according to claim 2, characterized in that, The current fully open temperature difference satisfies the following formula: in, This indicates the temperature difference at the current moment when it is fully open. This indicates that the pre-stored full-open temperature difference is stored. This indicates the impact of water flow deviation on the temperature difference at the current fully open position; α is the water flow deviation influence factor. It is a pre-stored full-open temperature difference value The corresponding rated water flow rate, It is the current water flow rate; This represents the impact of ambient temperature difference on the current fully open temperature difference, where β is the ambient temperature difference influence factor, and R is the normal adjustment value set by the environment in which the heat pump unit system is located. It is the ambient temperature at the current moment.

4. The heat pump unit system according to claim 3, characterized in that, The required temperature difference at the current moment satisfies the following formula: in: This indicates the current temperature difference required. This indicates the system's total outlet water set temperature. This indicates the current total inlet water temperature of the system.

5. The heat pump unit system according to claim 4, characterized in that, The number of power supply units required at the current moment satisfies the following formula: Where, N R This indicates the number of energy supply units required at the current moment. This indicates the current temperature difference required. N represents the temperature difference at the current moment when the circuit is fully open. total This indicates the total number of energy supply units contained in the heat pump unit system.

6. The heat pump unit system according to claim 3, characterized in that, The range of values ​​for the corrected normal quantity is (5-9).

7. The heat pump unit system according to claim 1, characterized in that, The startup sequence and timing of each power supply unit in the power supply unit startup rules are as follows: For users with limited circuit overcurrent capacity, the required power supply units will be activated sequentially, with an interval of 3-8 seconds between activations. For users whose circuit overcurrent is sufficient to simultaneously activate the required power supply units, the required power supply units will be activated simultaneously.

8. The heat pump unit system according to any one of claims 1-7, characterized in that, The energy supply unit includes several independent heat pump units.

9. The heat pump unit system according to any one of claims 1-7, characterized in that, When the power supply unit includes several compressors, a four-way valve, a condenser, an expansion valve, an evaporator, and a fan, the several compressors share the same fan, the same evaporator, and the same condenser.

10. The heat pump unit system according to claim 1, characterized in that, The water circuit module includes a buffer water tank, which is connected to the system's main water outlet, main water inlet, and user water outlet of the heat pump unit system via water circuits.

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