Defrosting control method

Abstract

The invention discloses a defrosting control method. The defrosting control method comprises the following steps that the corresponding moisture content before and after a refrigeration house is cooled is obtained; calculating a frost layer conversion rate according to the moisture content; and the defrosting period and the defrosting time are determined according to the frost layer conversion rate. According to the defrosting control method, accurate control over defrosting operation is achieved, unnecessary defrosting times and overlong defrosting time are effectively reduced, and electric energy and heat energy are saved; the extra heat load in the refrigeration house caused by excessive defrosting is reduced, the overall operation efficiency and the energy-saving effect of the refrigeration house are improved, the stability of the temperature and humidity environment of the refrigeration house is improved, and the refrigeration house is more suitable for food, medicine and other scenes with strict requirements for storage conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of refrigeration control, and particularly to a defrost control method. Background Art

[0002] The defrosting of the air cooler in the existing cold storage refrigeration system generally adopts a fixed defrosting cycle and a fixed single defrosting time. Since the wet load of the cold storage varies with the environment, season and the situation of the goods in the warehouse, the fixed defrosting mode is likely to cause the following problems:

[0003] On the one hand, defrosting is started when the frost layer has not accumulated to a sufficient thickness, wasting electric energy and heat energy; on the other hand, when the frost layer has completely melted, the defrosting operation continues, resulting in energy waste and an additional increase in the internal heat load of the warehouse, reducing the overall operating efficiency. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a defrost control method, which realizes precise control of the defrosting operation, effectively reduces unnecessary defrosting times and excessive defrosting time, saves electric energy and heat energy; reduces the additional internal heat load of the cold storage caused by excessive defrosting, improves the overall operating efficiency and energy-saving effect of the cold storage, improves the stability of the temperature and humidity environment of the cold storage, and is more suitable for scenarios with strict requirements for storage conditions such as food and medicine.

[0005] The present invention provides a defrost control method, including the following steps:

[0006] Obtain the moisture content corresponding to before and after the temperature reduction of the cold storage;

[0007] Calculate the frost layer conversion rate according to the moisture content;

[0008] Determine the defrosting cycle and defrosting time according to the frost layer conversion rate.

[0009] In one embodiment, the obtaining of the moisture content corresponding to before and after the temperature reduction of the cold storage further includes:

[0010] Obtain the temperature and relative humidity corresponding to before and after the temperature reduction of the cold storage;

[0011] Find the moisture content corresponding to before and after the temperature reduction according to the temperature and relative humidity.

[0012] In one embodiment, the calculating of the frost layer conversion rate according to the moisture content further includes:

[0013] Calculate the frost formation water volume according to the moisture content corresponding to before and after the temperature reduction;

[0014] Calculate the frost layer conversion rate according to the frost formation water volume and the defrost drainage volume.

[0015] In one embodiment, determining the defrosting cycle and defrosting time according to the frost layer conversion rate further includes:

[0016] Constructing a dynamic control model based on the frost accumulation amount, frost layer conversion rate, cumulative operation time of the air cooler, and historical data;

[0017] Estimating the defrosting cycle through the dynamic control model, and calculating the single - time defrosting time through a calculation formula.

[0018] In one embodiment, the calculation formula for the frost accumulation amount is:

[0019] ΔW = W 初始含湿量 - W 最终含湿量

[0020] Where ΔW is the frost accumulation amount, W 初始含湿量 is the moisture content before temperature reduction, and W 最终含湿量 is the moisture content after temperature reduction.

[0021] In one embodiment, the calculation formula for the frost layer conversion rate is:

[0022] ηtrans = (M 实际排水量 / ΔW) × 100%

[0023] Where M 实际排水量 is the actual amount of water discharged during defrosting in the defrosting process, and ΔW is the frost accumulation amount.

[0024] In one embodiment, the calculation formula for the defrosting time is:

[0025] t 除霜 = k × (ΔW×ηtrans) / Q 热源

[0026] Where k is the safety margin coefficient, and its value range is generally 1.1 - 1.3; Q 热源 is the heating power of the heat source provided during defrosting or the heat input rate.

[0027] The defrosting control method provided by the present invention realizes precise control of defrosting operations, effectively reduces unnecessary defrosting times and overly long defrosting times, saves electric energy and heat energy; reduces the additional internal heat load in the cold storage caused by excessive defrosting, improves the overall operation efficiency and energy - saving effect of the cold storage, improves the stability of the temperature and humidity environment in the cold storage, and is more suitable for scenarios with strict requirements for storage conditions such as food and medicine. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0029] Figure 1 It is a schematic flow chart of the defrosting control method provided by the present invention. Specific embodiments

[0030] The following will describe in detail specific embodiments of the present invention in conjunction with the drawings. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the description of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0031] In the description of the present invention, unless otherwise clearly defined and limited, terms such as "set", "installed", "connected", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0032] The orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use. It is only for the convenience of description and simplification of the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0033] Terms such as "first", "second", "third", etc. are only used to distinguish elements with similar attributes, rather than indicating or implying relative importance or a specific order.

[0034] The term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion. In addition to including the listed elements, it may also include other elements not specifically listed.

[0035] Please refer to Figure 1 , the defrosting control method provided by the present invention includes the following steps:

[0036] S1, obtain the moisture content corresponding to before and after the temperature reduction of the cold storage.

[0037] It is understandable that the above steps may further include:

[0038] S101, obtaining the corresponding temperature and relative humidity before and after the cold storage is cooled down.

[0039] It can be known that the temperature and relative humidity before and after the cooling can be measured by a temperature sensor and a humidity sensor. The number of the temperature sensor and the humidity sensor for measurement can be multiple, and they are located at different positions in the cold storage. The average value of the temperature data of the multiple temperature sensors can be used as the temperature data. At the same time, the average value of the data of the multiple humidity sensors located at different positions can also be used as the humidity data.

[0040] S102, finding the corresponding moisture content before and after the cooling according to the temperature and relative humidity.

[0041] It is understandable that the moisture content can be determined by a standard psychrometric chart of humid air or a table lookup method. Among them, both the standard psychrometric chart of humid air and the table lookup method can determine the corresponding moisture content through two parameters of temperature and humidity. The standard psychrometric chart of humid air and the standard psychrometric chart of humid air are both made according to the actual situation.

[0042] S2, calculating the frost layer conversion rate according to the moisture content.

[0043] It is understandable that the above steps may further include:

[0044] S201, calculating the frost formation water volume according to the corresponding moisture content before and after the cooling.

[0045] It can be known that the calculation formula for the frost formation water volume is:

[0046] ΔW = W 初始含湿量 - W 最终含湿量

[0047] In the formula, ΔW is the frost formation water volume, W 初始含湿量 is the moisture content before the cooling, and W 最终含湿量 is the moisture content after the cooling.

[0048] It is understandable that from the above calculation formula, it can be known that the calculation of the theoretical frost formation water volume is relatively idealized, that is, the reduced moisture content in the cold storage is defaulted to be converted into the frost formation water volume.

[0049] S202, calculating the frost layer conversion rate according to the frost formation water volume and the defrost drainage volume.

[0050] It is understandable that the calculation formula for the above frost layer conversion rate is:

[0051] ηtrans = (M 实际排水量 / ΔW) × 100%

[0052] where M 实际排水量 is the actual amount of water discharged during defrosting, and ΔW is the amount of frost formed.

[0053] It can be known that M 实际排水量 is the amount of water discharged during the actual defrosting process, which is defaulted to the ideal state where all the frost has melted.

[0054] S3. Determine the defrosting cycle and defrosting time according to the frost layer conversion rate.

[0055] The above steps may further include:

[0056] S301. Construct a dynamic control model based on the amount of frost formed, the frost layer conversion rate, the cumulative running time of the cooling fan, and historical data.

[0057] It can be known that the dynamic control model can be expressed by the function T_period = f(ΔW, t_fan, η_trans). This function belongs to an empirical formula or an empirical regression model: the formula can be a linear or non-linear empirical regression model or a mathematical model, which is mainly regressed based on historical operation data and on-site experience. Usually, an empirical function regression model is adopted, such as a linear function, a polynomial function, an exponential function, or a power function, etc. The more common forms include but are not limited to:

[0058] Linear model (such as): T_period = a * ΔW + b * t_fan + c * η_trans + d;

[0059] Non-linear empirical model (such as power function model): T_period = a * (ΔW)^b * (t_fan)^c * (η_trans)^d; Exponential or logarithmic model: T_period = a * e^(bΔW + c t_fan + dη_trans);

[0060] The above parameters such as a, b, c, d, e, da and t are determined through regression analysis of historical data. The best matching selection can be made according to the actual operation data of different cold storages.

[0061] S302, estimating the defrosting cycle through the dynamic control model and calculating the single defrosting time through the calculation formula.

[0062] It can be understood that the calculation formula for the single defrosting time can be expressed as:

[0063] t 除霜 = k × (ΔW×ηtrans) / Q 热源

[0064] In the formula, k is the safety margin coefficient, and its value range is generally 1.1 - 1.3; Q 热源 is the heating power or heat input rate of the heat source provided during defrosting.

[0065] From the above description, it can be known that the defrost control method provided by the present invention realizes precise control of defrosting operations, effectively reduces unnecessary defrosting times and excessive defrosting time, saves electric energy and heat energy; reduces the additional internal heat load in the cold storage caused by excessive defrosting, improves the overall operation efficiency and energy-saving effect of the cold storage, improves the stability of the temperature and humidity environment in the cold storage, and is more suitable for scenarios with strict requirements for storage conditions such as food and medicine.

[0066] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. A defrosting control method, characterized in that, It includes the following steps: Obtain the moisture content corresponding to before and after the cold storage is cooled down; Calculate the frost layer conversion rate according to the moisture content; Determine the defrosting period and defrosting time according to the frost layer conversion rate.

2. The defrosting control method according to claim 1, wherein The obtaining of the moisture content corresponding to before and after the cold storage is cooled down further includes: Obtain the temperature and relative humidity corresponding to before and after the cold storage is cooled down; Look up the moisture content corresponding to before and after the cooling according to the temperature and relative humidity.

3. The defrosting control method according to claim 2, wherein The calculating of the frost layer conversion rate according to the moisture content further includes: Calculate the frost formation water volume according to the moisture content corresponding to before and after the cooling; Calculate the frost layer conversion rate according to the frost formation water volume and the defrosting drainage volume.

4. The defrosting control method according to claim 3, characterized in that, The determining of the defrosting period and defrosting time according to the frost layer conversion rate further includes: Construct a dynamic control model according to the frost formation water volume, the frost layer conversion rate, the cumulative operation time of the air cooler and historical data; Estimate the defrosting period through the dynamic control model, and calculate the single defrosting time through a calculation formula.

5. The defrosting control method according to claim 3, characterized in that, The calculation formula for the frost formation water volume is: ΔW = W 初始含湿量 - W 最终含湿量 where ΔW is the frosting water amount, W 初始含湿量 is the moisture content before cooling, and W 最终含湿量 is the moisture content after cooling.

6. The defrosting control method according to claim 5, wherein The calculation formula for the frost layer conversion rate is: ηtrans = (M 实际排水量 / ΔW) × 100% Where M 实际排水量 is the actual defrost water discharge during the defrosting process, and ΔW is the frost formation water volume.

7. The defrosting control method according to claim 6, characterized in that, The calculation formula for the defrosting time is: t 除霜 = k × (ΔW×ηtrans) / Q 热源 where k is the safety margin coefficient, and its value range is generally 1.1 to 1.3; Q 热源 is the heating power or heat input rate of the heat source provided during defrosting.

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