A control method for a greenhouse ground-source heat pump heating device

Abstract

The application relates to a greenhouse ground source heat pump heating device control method, which comprises the following steps: S1, collecting greenhouse environment information and weather forecast information; S2, calculating a target heating temperature according to the greenhouse environment information and the weather forecast information; S3, judging whether to start the ground source heat pump by comparing a current indoor environment temperature with the target heating temperature, if yes, executing step S4, otherwise returning to step S2; and S4, further calculating a water outlet target temperature, and setting the water outlet temperature as the target temperature, and then returning to step S2. Compared with the prior art, the application can fully utilize historical data and weather prediction information, dynamically adjust the starting condition of the ground source heat pump and the setting temperature of the water outlet, and is suitable for different outdoor environments, so that the energy saving and consumption reduction effect is achieved; the application has strong universality, can be applied to greenhouses of different regions and different crops by adjusting a correction model, and has important significance for actual ground source heat pump heating system regulation and control.

Description

Technical Field

[0001] This invention relates to the field of agricultural automation technology, and in particular to a control method for greenhouse ground source heat pump heating equipment. Background Technology

[0002] With the development of intelligent agriculture and the advancement of greenhouse construction, more and more planting enterprises and farmers are using intelligent greenhouses to meet their planting needs. Meanwhile, with the development of the big data era, many agricultural greenhouses have accumulated historical data through environmental data collection. However, due to technological limitations and user skill levels, the control of most actuators within greenhouses is still largely manual. Users primarily rely on years of planting experience and real-time sensor data feedback to control the actuators. While this method can meet the most basic planting requirements to some extent, it is inefficient and wasteful in terms of efficiency and energy consumption. This is especially true in greenhouses equipped with heating facilities. Taking ground source heat pumps as an example, ground source heat pump technology utilizes geothermal resources, such as soil, groundwater, or solar and geothermal energy absorbed and stored in rivers and lakes. By inputting a small amount of high-grade energy, it transfers low-grade heat energy to high-grade heat energy, thereby providing indoor heating. At present, most greenhouse managers still manually rely on experience to set the on / off time and outlet temperature, and cannot make full use of indoor and outdoor environmental factors and past data, so they cannot achieve intelligent control and the control effect is poor. When dealing with heating needs under different weather conditions, it is difficult to ensure timely and dynamic adjustment of the ground source heat pump's opening conditions and outlet temperature setting. In severe weather, there is even a risk of freezing damage. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art by providing a control method for greenhouse ground source heat pump heating equipment, which can dynamically adjust the start-up conditions and outlet temperature of the ground source heat pump in a timely manner, thereby adapting to the heating needs of different environments and achieving energy-saving effects.

[0004] The objective of this invention can be achieved through the following technical solution: a control method for a greenhouse ground source heat pump heating device, comprising the following steps:

[0005] S1. Collect greenhouse environmental information and weather forecast information;

[0006] S2. Calculate the target heating temperature based on greenhouse environment information and weather forecast information;

[0007] S3. By comparing the current indoor ambient temperature with the target heating temperature, determine whether to turn on the ground source heat pump. If the determination is yes, proceed to step S4; otherwise, return to step S2.

[0008] S4. Based on the greenhouse environment information and weather forecast information, further calculate the target temperature of the outlet and set the outlet temperature as the target temperature, then return to step S2.

[0009] Furthermore, the greenhouse environmental information collected in step S1 includes indoor temperature, outdoor temperature, and outdoor daily cumulative light intensity.

[0010] Furthermore, the weather forecast information collected in step S1 is specifically the lowest outdoor nighttime temperature.

[0011] Furthermore, the specific formula for calculating the target heating temperature in step S2 is as follows:

[0012] Th eat =T target +ΔT radsum +ΔT Out +ΔT outnig

[0013]

[0014] Among them, Th eat T is the target heating temperature. target The set temperature for planting, ΔT radsum The cumulative correction value for outdoor solar irradiance, ΔT outnig This is the correction value for the lowest nighttime temperature, ΔT. Out Here is the outdoor temperature correction value, ΔT is the correction function norm, and ΔT max With ΔT min These are the upper and lower bounds of the correction for ΔT, respectively, where x is the independent variable of the environmental factor. low With x high Let x be the range of values, and α and β be the correction coefficients, both of which are constants.

[0015] Furthermore, step S3 specifically includes the following steps:

[0016] S31. Obtain the working status of the ground source heat pump in the previous time step according to the set time step;

[0017] S32. Based on the working status of the ground source heat pump in the previous time step, compare the current indoor temperature with the target heating temperature to determine whether to turn on the ground source heat pump. If the determination is yes, proceed to step S4; otherwise, return to step S2.

[0018] Furthermore, the time step set in step S31 is specifically 5 minutes.

[0019] Furthermore, the ground source heat pump's operating state in the previous time step was specifically either on or off.

[0020] Furthermore, step S32 specifically includes the following steps:

[0021] S321. If the ground source heat pump was in the "on" state in the previous time step, then execute step S322.

[0022] If the ground source heat pump was in the off state in the previous time step, then proceed to step S323;

[0023] S322. Compare the current indoor temperature with the target heating temperature. If the current indoor temperature is greater than the target heating temperature, turn off the ground source heat pump system and return to step S2; otherwise, turn on the ground source heat pump system and proceed to step S4.

[0024] S323. Compare the current indoor temperature with the target heating temperature. If the current indoor temperature is lower than the target heating temperature, turn on the ground source heat pump system and then proceed to step S4; otherwise, keep the ground source heat pump system off and then return to step S2.

[0025] Furthermore, the specific process of starting the ground source heat pump system in steps S322 and S323 is as follows: lay out the inner insulation net and turn on the switches of each device in the ground source heat pump system.

[0026] Furthermore, the specific formula for calculating the target temperature of the outlet in step S4 is as follows:

[0027] T water =T initial +ΔT tempaver +ΔT radsum

[0028]

[0029] Among them, T water T is the target temperature at the outlet. initial ΔT is the initial setpoint for the outlet temperature, determined by the nighttime minimum temperature predicted by the weather forecast. tempaver This is a correction value for the average indoor daytime temperature, ΔT. radsum This is the cumulative correction value for outdoor sunlight intensity.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] I. This invention collects historical environmental data and weather forecasts from inside and outside the greenhouse to calculate the target heating temperature and the target outlet temperature. By comparing the current indoor temperature with the target heating temperature, it determines whether to activate the ground source heat pump system and sets the outlet temperature. This allows for full utilization of historical data and weather forecasts to dynamically adjust the activation / deactivation of the ground source heat pump and the outlet temperature setting to adapt to different outdoor heating needs. For example, heating can be activated earlier in cold, inclement weather to increase the outlet temperature, while heating can be delayed in milder weather to decrease the outlet temperature, resulting in energy savings and reduced consumption.

[0032] Second, when calculating the target heating temperature and the target outlet temperature, this invention adopts a correction value paradigm, which can determine the correction function for different environmental factors by combining relevant historical data or preset conditions. This allows the correction model to be adjusted in practical applications to meet the greenhouse needs of different crops in different regions, thereby improving the universality of this invention. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the method flow of the present invention;

[0034] Figure 2 The curve is a schematic representation of the general form of the correction function;

[0035] Figure 3 This is a block diagram of the switching control logic for a ground source heat pump system.

[0036] Figure 4 This is a schematic diagram of the cumulative correction function curve for outdoor sunlight in the embodiment;

[0037] Figure 5 This is a schematic diagram of the nighttime minimum temperature correction function curve in the embodiment;

[0038] Figure 6 This is a schematic diagram of the outdoor temperature correction function curve in the embodiment;

[0039] Figure 7 This is a schematic diagram of the outlet temperature correction function curve in the embodiment;

[0040] Figure 8 The figure shows a schematic diagram of the indoor daytime average temperature correction function curve in the example. Detailed Implementation

[0041] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0042] Example

[0043] like Figure 1As shown, a control method for a greenhouse ground source heat pump heating device includes the following steps:

[0044] S1. Collect greenhouse environmental information and weather forecast information. The greenhouse environmental information includes indoor temperature, outdoor temperature, and outdoor daily cumulative light intensity. The weather forecast information specifically includes the outdoor nighttime minimum temperature.

[0045] S2. Calculate the target heating temperature based on greenhouse environment information and weather forecast information:

[0046] Th eat =T target +ΔT radsum +ΔT Out +ΔT outnig

[0047]

[0048] In the formula, T heat T is the target heating temperature. target The set temperature for planting, ΔT radsum The cumulative correction value for outdoor solar irradiance, ΔT outnig This is the correction value for the lowest nighttime temperature, ΔT. Out This is the outdoor temperature correction value, and ΔT is the correction function norm (e.g., ...). Figure 2 As shown), ΔT max With ΔT min These are the upper and lower bounds of the correction for ΔT, respectively, where x is the independent variable of the environmental factor. low With x high Let x be the range of values, and α and β be correction coefficients, both of which are constants.

[0049] S3. By comparing the current indoor ambient temperature with the target heating temperature, determine whether to turn on the ground source heat pump. If the determination is yes, proceed to step S4; otherwise, return to step S2.

[0050] Specifically, such as Figure 3 As shown, the system first determines whether the ground source heat pump was turned on in the previous time step. In this embodiment, the time step is set to 5 minutes. If it was turned on, the current indoor temperature is compared with the target heating temperature T. heat In comparison, the temperature inside the greenhouse is greater than the target heating temperature T. heat If the ground source heat pump system is shut down, then return to step S2; otherwise, lay out the inner insulation net and turn on the heating system, then proceed to step S4.

[0051] If turned off, the current indoor temperature will be compared with the target heating temperature T. heat For comparison, if the indoor temperature is lower than the target heating temperature T heatIf the internal insulation netting is laid out and the ground source heat pump heating system is turned on, then step S4 is executed; otherwise, the system is kept off and then returned to step S2.

[0052] S4. Based on greenhouse environmental information and weather forecast information, further calculate the target temperature of the water outlet and set the water outlet temperature as the target temperature. Then return to step S2. The specific formula for calculating the target temperature of the water outlet is as follows:

[0053] T water =T initial +ΔT tempaver +ΔT radsum

[0054]

[0055] In the formula, T water T is the target temperature at the outlet. initial ΔT is the initial setpoint for the outlet temperature, determined by the nighttime minimum temperature predicted by the weather forecast. tempaver This is a correction value for the average indoor daytime temperature, ΔT. radsum This is the cumulative correction value for outdoor sunlight intensity.

[0056] This embodiment applies the above-mentioned technical solution and conducts an experiment in a Venlo-type greenhouse in Chongming, Shanghai, from November 2022 to March 2023. The greenhouse crop was Anthurium flowers, with a suitable temperature of 17-28℃. The greenhouse's ground source heat pump heating facility was a vertical buried pipe ground source heat pump system from Carrier, with radiant coils inside the greenhouse transferring heat. In winter, the heat pump main unit draws hot water at 35-55℃ to supply the indoor radiant coils, thereby achieving a heating effect. Temperature, humidity, and light intensity sensors were installed at the central height of the greenhouse, and a meteorological data acquisition box was placed outdoors to collect information such as outdoor temperature, outdoor humidity, and outdoor light intensity.

[0057] Collect relevant environmental information about the greenhouse: indoor temperature, outdoor temperature, and daily cumulative outdoor light intensity; obtain weather forecast information: outdoor nighttime minimum temperature.

[0058] Calculate the target heating temperature T heat ;

[0059] T heat =T target +ΔT radsum +ΔT out +ΔT outnig

[0060] Based on the specific needs of the Chongming Flower Greenhouse in Shanghai, a modified model for different environmental factors was designed:

[0061] First T targetThe required planting temperature varies depending on the time of day. The day is divided into five time periods (6:00-10:00, 10:00-14:00, 14:00-18:00, 18:00-24:00, 24:00-6:00), and the corresponding planting temperatures are (18℃, 23℃, 21℃, 17℃, 15℃).

[0062] ΔT radsum To correct for cumulative outdoor solar irradiance, ΔT was designed based on historical cumulative outdoor solar irradiance data for Chongming during winter. max ΔT min , α, β, x low x high The specific correction function curve is as follows: Figure 4 As shown.

[0063] ΔT outnig For nighttime minimum temperature correction, ΔT is designed based on the range of nighttime minimum temperatures in Chongming during winter. max ΔT min , α, β, x low x high The specific correction function curve is as follows: Figure 5 As shown.

[0064] ΔT Out For outdoor temperature correction, ΔT is designed based on the temperature range of Chongming in winter. max ΔT min , α, β, x low x high The specific correction function curve is as follows: Figure 6 As shown.

[0065] Therefore, based on environmental data and weather forecast information, T is calculated. heat .

[0066] The next step is to determine the start-up conditions of the ground source heat pump system, including the following steps:

[0067] S301. Determine whether the ground source heat pump was turned on in the previous time step. The time step is 5 minutes. If it was turned on, execute S302. If it was turned off, execute S303.

[0068] S302, compare the indoor temperature with the target heating temperature Y heat If the temperature inside the greenhouse is higher than the target heating temperature, the ground source heat pump system is shut down; otherwise, the inner insulation netting is laid out and the heating system is turned on.

[0069] S303. Compare the indoor temperature with the target heating temperature. If the indoor temperature is lower than the target heating temperature T... heatIf the heating is on, then the inner insulation netting should be laid out and the ground source heat pump heating system should be turned on; otherwise, it should be kept off.

[0070] If the real-time indoor temperature is less than T heat Then calculate the target temperature T at the outlet. water Specific T water The calculation method is as follows:

[0071] T water =T initial +ΔT tempaver +ΔT radsum

[0072] Y initial The initial setpoint for the outlet temperature is determined by the predicted nighttime minimum temperature. Based on the range of nighttime minimum temperatures in Chongming during winter and the actual suitable setpoint range for the ground source heat pump outlet temperature, ΔT is designed. max ΔT min , α, β, x low x high The specific correction function curve is as follows: Figure 7 As shown.

[0073] ΔT tempaver To correct for the average daytime temperature indoors, ΔT is designed based on the range of the greenhouse's average daily temperature. max ΔT min , α, β, x low x high The specific correction function curve is as follows: Figure 8 As shown.

[0074] ΔT radsum To correct for cumulative outdoor solar irradiance, ΔT was designed based on historical data of cumulative outdoor solar irradiance in Chongming during winter. max ΔT min , α, β, x low x high The specific correction function curve is as follows: Figure 4 As shown.

[0075] Therefore, based on environmental data and weather forecast information, T is calculated. water Then, set the outlet temperature to that value and start the ground source heat pump to heat the greenhouse.

[0076] Assuming the current time falls between 18:00 and 24:00, the set planting temperature is 17℃, the predicted nighttime low is -5℃, and the daily cumulative outdoor sunlight from sunrise is 0.2J / m². 2 The outdoor temperature is -2℃, and the average indoor daytime temperature from sunrise is 19℃. Based on the formula and correction curves for various environmental factors, T can be calculated. heat=17+(-1)+(1)+(1.2)=18.2℃. If the indoor temperature is less than 18.2℃, then T can be calculated. water = (50) + (0.4) + (-1) = 49.4℃, then set the outlet temperature of the ground source heat pump to 49.4℃ and turn on the heating.

[0077] In summary, compared with traditional single-temperature-factor threshold control algorithms, this technical solution can fully utilize historical data and weather forecast information to dynamically adjust the start-up time and outlet temperature setting to adapt to different outdoor environments. It can start heating earlier in cold and severe weather to increase the outlet temperature, and delay heating in milder weather to decrease the outlet temperature, resulting in energy savings and reduced consumption. Furthermore, it has strong versatility; by adjusting and correcting the model in greenhouses of different regions and crops, it can be applied to different greenhouses, which is of great significance for the actual control of ground source heat pump heating systems.

Claims

1. A control method for a greenhouse ground source heat pump heating device, characterized in that, Includes the following steps: S1. Collect greenhouse environmental information and weather forecast information. The greenhouse environmental information collected includes indoor temperature, outdoor temperature, and outdoor daily cumulative light intensity. The collected weather forecast information specifically refers to the lowest outdoor temperature at night; S2. Calculate the target heating temperature based on greenhouse environment information and weather forecast information; The specific formula for calculating the target heating temperature is as follows: ， in, The target heating temperature, Set the temperature for planting. This is the cumulative correction value for outdoor sunlight. This is a correction value for the lowest nighttime temperature. This is a correction value for outdoor temperature. To correct the function normal form, and They are respectively The upper and lower limits of the correction, x As environmental factors, and for x The range of values ​​for , , These are correction coefficients, both of which are constants; S3. By comparing the current indoor ambient temperature with the target heating temperature, determine whether to turn on the ground source heat pump. If the determination is yes, proceed to step S4; otherwise, return to step S2. S4. Based on the greenhouse environment information and weather forecast information, further calculate the target temperature of the outlet and set the outlet temperature as the target temperature, then return to step S2.

2. The control method for a greenhouse ground source heat pump heating device according to claim 1, characterized in that, Step S3 specifically includes the following steps: S31. Obtain the working status of the ground source heat pump in the previous time step according to the set time step; S32. Based on the working status of the ground source heat pump in the previous time step, compare the current indoor temperature with the target heating temperature to determine whether to turn on the ground source heat pump. If the determination is yes, proceed to step S4; otherwise, return to step S2.

3. The control method for a greenhouse ground source heat pump heating device according to claim 2, characterized in that, In step S31, the time step is set to 5 minutes.

4. The control method for a greenhouse ground source heat pump heating device according to claim 2, characterized in that, The specific operating state of the ground source heat pump in the previous time step was either on or off.

5. The control method for a greenhouse ground source heat pump heating device according to claim 4, characterized in that, Step S32 specifically includes the following steps: S321. If the ground source heat pump was in the "on" state in the previous time step, then execute step S322. If the ground source heat pump was in the off state in the previous time step, then proceed to step S323; S322. Compare the current indoor temperature with the target heating temperature. If the current indoor temperature is greater than the target heating temperature, turn off the ground source heat pump system and return to step S2; otherwise, turn on the ground source heat pump system and proceed to step S4. S323. Compare the current indoor temperature with the target heating temperature. If the current indoor temperature is lower than the target heating temperature, turn on the ground source heat pump system and then proceed to step S4; otherwise, keep the ground source heat pump system off and then return to step S2.

6. The control method for a greenhouse ground source heat pump heating device according to claim 5, characterized in that, The specific process of starting the ground source heat pump system in steps S322 and S323 is as follows: lay out the inner insulation net and turn on the switches of each device in the ground source heat pump system.

7. The control method for a greenhouse ground source heat pump heating device according to claim 1, characterized in that, The specific formula for calculating the target temperature at the outlet in step S4 is as follows: ， in, The target temperature at the outlet. The initial setpoint for the outlet temperature is determined by the nighttime minimum temperature predicted by the weather forecast. This is a correction value for the average indoor daytime temperature. This is the cumulative correction value for outdoor sunlight intensity.

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