阅读说明：本技术 一种热泵结霜积灰的判定方法 (method for judging frosting and dust deposition of heat pump ) 是由 赵密升 钟惠安 张勇 于 2019-08-20 设计创作，主要内容包括：本发明涉及热泵技术领域,具体涉及一种热泵结霜积灰的判定方法,包括以下步骤：S1:通过测试机组原始状态数据,记录换热器的数据,换热器的性能特征S2.通过机组实时运行数据,判定机组当前换热器的性能特征；S3.通过对比当前理论换热器性能特征及当前状态换热器的实际性能特征,判定机组的结霜程度。(the invention relates to the technical field of heat pumps, in particular to a method for judging frosting and dust deposition of a heat pump, which comprises the following steps: s1, recording data of the heat exchanger and performance characteristics S2 of the heat exchanger through testing the original state data of the unit, and judging the performance characteristics of the current heat exchanger of the unit through real-time operation data of the unit; and S3, judging the frosting degree of the unit by comparing the performance characteristics of the current theoretical heat exchanger with the actual performance characteristics of the current state heat exchanger.)

1. a method for judging frosting and dust deposition of a heat pump is characterized by comprising the following steps: the method comprises the following steps:

s1, recording data of a heat exchanger through testing original state data of a unit: rated heat exchange quantity and rated characteristic temperature difference;

s2, judging the theoretical performance characteristics of the current heat exchanger of the unit according to the real-time operation data of the unit: the theoretical performance characteristics of the heat exchanger are judged as follows: the theoretical heat exchange quantity of the current working condition is f (the current evaporation temperature, the current condensation temperature, the current suction superheat degree and the current supercooling degree) and the current coefficient of the compressor; under the condition, the theoretical characteristic temperature difference of heat exchange under the condition of no frost formation or no ash is equal to the theoretical heat exchange quantity of the current working condition and the rated characteristic temperature difference/the rated heat exchange quantity; the current actual characteristic temperature difference is equal to the current environment temperature-the current evaporation temperature;

s3, judging the frosting degree of the unit by comparing the performance characteristics of the current theoretical heat exchanger with the actual performance characteristics of the heat exchanger in the current state, before the unit enters defrosting, namely, before the unit enters defrosting, the heating capacity (the current heating capacity) under the current operating parameters of the heat exchanger is f (the current evaporation temperature, the current condensation temperature, the current suction superheat degree and the current supercooling degree) is compressor current coefficient, recording the current characteristic temperature difference of the heat exchanger, namely the current outdoor temperature of the heat exchanger-the current evaporation temperature of the heat exchanger, and under the working condition, if the theoretical characteristic temperature difference (ideal characteristic temperature difference) without frosting/ash is the current theoretical characteristic temperature difference of the heat exchanger/the standard heating capacity of the unit,

When the unit frosts, the heat exchange characteristic of the evaporator is changed, and then the frosting/ash formation degree is (the current characteristic temperature difference of the heat exchanger-the current theoretical characteristic temperature difference of the heat exchanger)/the current theoretical characteristic temperature difference of the heat exchanger; when the frosting degree is more than 1.03, judging that the frosting is slight; when the frosting degree is larger than 1.05, judging the frosting degree is moderate; when the frosting degree is more than 1.07, judging that the frosting is severe, and defrosting according to different frosting degrees in different accumulated time;

S4, after defrosting is carried out, and the unit state is stable, comparing the actual current performance characteristic and the current theoretical performance characteristic of the heat exchanger after the unit is defrosted by calculating the frosting/dust deposition degree, and judging the dust deposition degree of the current unit so as to judge the optimal defrosting time and prompt dust removal;

S5, correcting the normal heat exchange performance characteristics of the unit through the dust deposition degree;

And S6, replacing the normal heat exchange performance characteristics of the new unit with the performance characteristics of the original state of the unit to be used as defrosting judgment.

Technical Field

the invention relates to the technical field of heat pumps, in particular to a method for judging frosting and dust deposition of a heat pump.

Background

according to the traditional defrosting mode, on one hand, the judgment on the frosting degree of the unit is not accurate enough, and on the other hand, performance attenuation caused by dust deposition after the heat exchanger is used for a long time is ignored. If a certain machine has serious dust accumulation and even has no frost, the machine can be judged to have frost by mistake, so that the machine set is defrosted frequently.

Disclosure of Invention

The invention aims to provide a method for judging frosting and dust deposition of a heat pump, aiming at the defects in the prior art, and the method for judging frosting and dust deposition of the heat pump can prevent the frequent defrosting from being frequently carried out due to the occurrence of misjudgment.

the purpose of the invention is realized by the following technical scheme:

The method for judging the frosting and ash deposition of the heat pump comprises the following steps:

S1, recording data of a heat exchanger through testing original state data of a unit: rated heat exchange quantity and rated characteristic temperature difference;

S2, judging the theoretical performance characteristics of the current heat exchanger of the unit according to the real-time operation data of the unit: the theoretical performance characteristics of the heat exchanger are judged as follows: the theoretical heat exchange quantity of the current working condition is f (the current evaporation temperature, the current condensation temperature, the current suction superheat degree and the current supercooling degree) and the current coefficient of the compressor; under the condition, the theoretical characteristic temperature difference of heat exchange under the condition of no frost formation or no ash is equal to the theoretical heat exchange quantity of the current working condition and the rated characteristic temperature difference/the rated heat exchange quantity; the current actual characteristic temperature difference is equal to the current environment temperature-the current evaporation temperature;

s3, judging the frosting degree of the unit by comparing the performance characteristics of the current theoretical heat exchanger with the actual performance characteristics of the heat exchanger in the current state, before the unit enters defrosting, namely, before the unit enters defrosting, the heating capacity (the current heating capacity) under the current operating parameters of the heat exchanger is equal to f (the current evaporation temperature of the heat exchanger, the current condensation temperature of the heat exchanger, the current suction superheat degree of the heat exchanger and the current supercooling degree of the heat exchanger) is equal to the current coefficient of the compressor, recording the current characteristic temperature difference of the heat exchanger, which is the current outdoor temperature of the heat exchanger-the current evaporation temperature of the heat exchanger, and if the theoretical characteristic temperature difference (ideal characteristic temperature difference) without frosting/ash under the working condition is equal to the current heating,

When the unit frosts, the heat exchange characteristic of the evaporator is changed, and then the frosting/ash formation degree is (the current characteristic temperature difference of the heat exchanger-the current theoretical characteristic temperature difference of the heat exchanger)/the current theoretical characteristic temperature difference of the heat exchanger; when the frosting degree is more than 1.03, judging that the frosting is slight; when the frosting degree is larger than 1.05, judging the frosting degree is moderate; when the frosting degree is more than 1.07, judging that the frosting is severe, and defrosting according to different frosting degrees in different accumulated time;

S4, after defrosting is carried out, and the unit state is stable, comparing the actual current performance characteristic and the current theoretical performance characteristic of the heat exchanger after the unit is defrosted by calculating the frosting/dust deposition degree, and judging the dust deposition degree of the current unit so as to judge the optimal defrosting time and prompt dust removal;

S5, correcting the normal heat exchange performance characteristics of the unit through the dust deposition degree;

And S6, replacing the normal heat exchange performance characteristics of the new unit with the performance characteristics of the original state of the unit to be used as defrosting judgment.

The invention has the following beneficial effects: through this embodiment, can make the comparison to the current heat transfer characteristic of unit and the theoretical heat transfer characteristic under the ashless state after the unit defrosting, judge the deposition degree of unit, be used for reminding the customer to wash the heat exchanger on the one hand, on the other hand is used for revising the theoretical heat transfer characteristic of unit, prevents because the deposition misjudge frequently gets into the defrosting.

The present invention is further illustrated by the following examples, which are not to be construed as limiting the invention, and other embodiments may be devised by those skilled in the art without departing from the inventive concept.

Detailed Description

The invention is further described with reference to the following examples.

taking a certain set of test data as an example:

The specific implementation mode of the judging method for frost and ash deposition of the heat pump comprises the following steps:

S1, recording data of a heat exchanger through testing original state data of a unit;

Under the experimental environment, the ring temperature is-12 ℃, the evaporation temperature is-17 ℃, the condensation temperature is 43 ℃, the suction superheat degree is 5 ℃, the supercooling degree is 4 ℃, the unit heating capacity is 26.17KW, and the characteristic temperature difference of the heat exchanger is the environment temperature-the evaporation temperature is 5 DEG C

i.e. the characteristic temperature difference of the heat exchanger under the heat exchange quantity of 26.17KW is 5 DEG C

s2, judging the performance characteristics of the current heat exchanger of the unit according to the real-time operation data of the unit, and judging the performance characteristics of the heat exchanger (firstly, calculating the heat exchange quantity of the heat exchanger in the current state according to the parameters ET, CT, SCT and SSH (hereinafter, the characters are defined), and further calculating the performance characteristics of the heat exchanger under the heat exchange quantity): current theoretical heating capacity of the unit is f (current evaporation temperature, current condensation temperature, current suction superheat degree and current supercooling degree) and current coefficient of the compressor; under the condition, the theoretical characteristic temperature difference of heat exchange under the condition of no frost formation or no ash is equal to the theoretical heat exchange quantity of the current working condition and the rated characteristic temperature difference/the rated heat exchange quantity;

When the unit operates for a period of time, the following is fed back according to the unit test data: the current environment temperature is-13 deg.C, the evaporating temperature is-22 deg.C, the condensing temperature is 45 deg.C, the suction superheat degree is 5 deg.C, and the supercooling degree is 4 deg.C. According to the capacity calculation formula of the compressor of the unit, the theoretical heating capacity of the current unit is calculated to be 22.49 KW. At this time, the theoretical characteristic temperature difference of the unit is 22.49 × 5/26.17 — 4.3 ℃ if there is no frost/ash formation. The current actual characteristic temperature difference of the unit is-13 + 22-9 DEG C

the performance characteristics of the heat exchanger are judged as: under the rated heat exchange quantity, the heat exchange standard characteristic temperature difference of the heat exchanger under the condition of no frost formation/no ash is equal to the standard outdoor temperature-the standard evaporation temperature;

Explanation of the heating capacity: for a unit, the heating capacity depends on the compressor, and the heating capacity of the compressor depends on the current operating system parameters, including: 1. the evaporation temperature; 2. the condensation temperature; 3. the degree of superheat of the suction gas; 4. supercooling degree; 5. current coefficient or operating frequency (for multi-machine parallel systems, this coefficient also needs to be corrected according to the number of press starts); for a fixed frequency compressor, the current coefficient may have a heating capacity calculation formula for different compressors. Taking an Danfoss PCH model 034-4 compressor as an example, the temperature of the super-heated air is 5 ℃ and the super-cooled air is 4 ℃. The Q heating capacity is C0+ C1 + C2 + CT ^2+ C3 ^ ET 3+ C4 ^ ET + C5 ^ CT ^2+ C6 ^ ET 3+ C7 ^ ET 2+ C8 ^ ET ^ CT ^2+ C9 ^ CT ^3, wherein: C0-C9 are constants; ET: is the evaporation temperature; CT: the condensation temperature.

for convenience of description, the subsequent unit heating capacity is described in the following simplification: heating quantity Q ═ f (ET, CT, SSH, SCT) × K

Wherein: ET is the evaporation temperature, CT is the condensation temperature, SSH is the suction superheat, SCT is the condensation temperature, and K is the current coefficient.

description of heat exchange capacity of heat exchanger: for heat exchangers, the heat exchange performance was rated as follows: and under the rated heat exchange amount, evaluating the heat exchange capacity of the heat exchanger by using the characteristic temperature difference.

S3, judging the frosting degree of the unit by comparing the performance characteristics of the current theoretical heat exchanger with the actual performance characteristics of the current state heat exchanger, before the unit is defrosted, that is, the heating capacity (current heating capacity) under the current operation parameters of the heat exchanger is f (current evaporation temperature of the heat exchanger, current condensation temperature of the heat exchanger, current suction superheat degree of the heat exchanger, current supercooling degree of the heat exchanger) and current coefficient of the compressor, the current characteristic temperature difference of the heat exchanger is recorded as the current outdoor temperature of the heat exchanger-current evaporation temperature of the heat exchanger, if the theoretical characteristic temperature difference (ideal characteristic temperature difference) without frosting or ash is equal to the current heating capacity of the heat exchanger, the standard characteristic temperature difference of the heat exchanger/standard heating capacity of the heat exchanger under the working condition, when the unit frosting occurs, the heat exchange characteristic of the evaporator is changed, then the frosting/ash formation degree is (the current characteristic temperature difference of the heat exchanger-the ideal characteristic temperature difference of the heat exchanger)/the ideal characteristic temperature difference of the heat exchanger; when the frosting degree is more than 1.03, judging that the frosting is slight; when the frosting degree is larger than 1.05, judging the frosting degree is moderate; and when the frosting degree is more than 1.07, judging that the frost is heavily frosted, and defrosting the frost in different accumulated time according to different frosting degrees.

The current frost/ash degree is (9-4.3)/4.3 is 1.09, the severe frost is formed, the current time interval of the compressor is more than 10min after the last defrosting, and the unit enters the defrosting mode.

S4, after defrosting is carried out, and the unit state is stable, comparing the actual current performance characteristic and the current theoretical performance characteristic of the heat exchanger after the unit is defrosted by calculating the frosting/dust deposition degree, and judging the dust deposition degree of the current unit so as to judge the optimal defrosting time and prompt dust removal;

after the defrosting of the unit is finished, the unit enters a stable running state again, and the test data of the unit is fed back as follows: the current ambient temperature is-13 deg.C, the evaporating temperature is-19 deg.C, the condensing temperature is 45 deg.C, the degree of superheat of air-breathing is 5 deg.C, and the degree of supercooling is 4 deg.C. According to the capacity calculation formula of the compressor of the unit, the theoretical heating capacity of the current unit is calculated to be 24.55 KW. In this case, the theoretical characteristic temperature difference of the unit is 24.55 × 5/26.17 — 4.7 ℃ in the frost-free state. The current actual characteristic temperature difference of the unit is-13 + 19-6 ℃, and the heat exchange characteristic of the current unit is changed under the frostless condition due to dust deposition.

S5, correcting the normal heat exchange performance characteristics of the unit through the dust deposition degree;

Then the heat exchange characteristics of the current heat exchanger of the unit are replaced by: when the heat exchange quantity is 24.55KW, the characteristic temperature difference is 6 DEG C

And S6, replacing the normal heat exchange performance characteristics of the new unit with the performance characteristics of the original state of the unit to be used as defrosting judgment.

In subsequent operation, the unit judges whether to defrost according to the performance characteristics of the heat exchanger.

Through this embodiment, can make the comparison to the current heat transfer characteristic of unit and the theoretical heat transfer characteristic under the ashless state after the unit defrosting, judge the deposition degree of unit, be used for reminding the customer to wash the heat exchanger on the one hand, on the other hand is used for revising the theoretical heat transfer characteristic of unit, prevents because the deposition misjudge frequently gets into the defrosting.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the protection scope of the present invention, although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.