CN102818332A

CN102818332A - Method and device for controlling auxiliary electric heating in multi-connected air conditioning system

Info

Publication number: CN102818332A
Application number: CN2012102740459A
Authority: CN
Inventors: 石靖峰; 李亚军; 曹锐; 孟建军
Original assignee: Qingdao Hisense Hitachi Air Conditioning System Co Ltd
Current assignee: Qingdao Hisense Hitachi Air Conditioning System Co Ltd
Priority date: 2012-08-02
Filing date: 2012-08-02
Publication date: 2012-12-12
Anticipated expiration: 2032-08-02
Also published as: CN102818332B

Abstract

The invention discloses a method and device for controlling auxiliary electric heating in a multi-connected air conditioning system. The method comprises the following steps: rated heat output information and rated power consumption information of each operating compressor in the multi-connected air conditioning system are obtained during heating operation; the rated electric heating capacity information, the rated electric heating power consumption information and the rated heat demand information of an indoor machine including an auxiliary electric heater are obtained; compressors and indoor machines including auxiliary electric heaters are selected, the sum of the rated heat of the selected compressors and the sum of the rated auxiliary electric heating capacity of the indoor machines including the auxiliary electric heaters are added so that the added sum is not smaller than the sum of the rated heat demand of the selected indoor machines including the auxiliary electric heaters and the sum of the power consumption of the selected compressors and the indoor machines including the auxiliary electric heaters is minimal. With the method and the device, the actual operation energy efficiency ratio of the multi-connected air conditioning system can be increased.

Description

Method and device for controlling auxiliary electric heating in multi-split air conditioning system

Technical Field

The invention relates to an intelligent energy-saving technology of an air conditioner, in particular to a method and a device for controlling auxiliary electric heating.

Background

Along with the continuous improvement of people's standard of living, under living and indoor operational environment, through installing air conditioning system for promote living and operational environment's travelling comfort, become an important selection that people improved the travelling comfort demand. The multi-split air conditioner technology is an important direction for air conditioner development because of the advantages of free control, high efficiency, energy conservation, convenience in installation and maintenance and the like.

A multi-split air conditioning system generally includes one or more outdoor units, one or more indoor units, and a line controller, where the line controller is connected to the indoor units, and the indoor units are connected to the outdoor units. The outdoor unit generally comprises an outdoor heat exchanger, a compressor and other refrigeration accessories; compared with a plurality of household air conditioners, the outdoor unit of the multi-split air conditioning system is shared, the equipment cost can be effectively reduced, the centralized management of each indoor unit can be realized, one indoor unit can be independently started to operate, a plurality of indoor units can also be simultaneously started to operate, and the control is more flexible.

The working efficiency of the multi-split air-conditioning system is related to the ambient temperature, the lower the ambient temperature is, the lower the working efficiency of the system is, when the ambient temperature is lower than-2 ℃, because the difference between the ambient temperature and the heating standard working condition is larger, the heat which can be provided by the multi-split air-conditioning system designed according to the standard working condition is far lower than that of the standard working condition, and the compressor works under a high compression ratio, so that the volumetric efficiency and the indicating efficiency of the compressor are inevitably reduced. In order to improve the operation efficiency and prolong the service life of the multi-split air-conditioning system, the method adopted by the prior art is to preheat the cold medium by adding auxiliary heat source equipment in an indoor unit or a water module and adopting an auxiliary electric heating method so as to ensure the starting and normal operation of the multi-split air-conditioning system and simultaneously improve the heat supply efficiency and the heat supply effect of a compressor.

Because the auxiliary electric heating method is adopted, energy is consumed, namely, the auxiliary electric heating is not energy-saving, and therefore the auxiliary electric heating is required to be controlled to reduce energy consumption.

At present, the method of controlling the auxiliary electric heating is mainly controlled according to the ambient temperature condition, for example, by setting an auxiliary electric heating on condition and an auxiliary electric heating off condition to control the on and off of the auxiliary electric heating, which will be briefly described below.

First, normal operation state

Under the heating condition, the auxiliary electric heating start-up conditions (all conditions are satisfied simultaneously) are as follows:

firstly, the temperature T of the outlet water_ow≤T_s-6 (. degree. C.), or, T_ow＜25（℃）；

Wherein, T_sIs the set temperature of the wire controller.

② outdoor ambient temperature T_oaThe temperature is less than or equal to N (DEG C), wherein N (minus 20-10) (DEG C) is defaulted to 4 ℃;

and thirdly, starting the outdoor compressor.

In the auxiliary electric heating condition, if there are 2 outdoor units, the outdoor environment temperature is the average value of the 2 outdoor unit environment temperatures, i.e. T_oa=(T_oa1+T_oa2)/2。

The auxiliary electric heating off condition (satisfying any one of the following conditions) is as follows:

firstly, the temperature T of the outlet water_ow≥T_s-3 (. degree. C.) and, T_ow≥30（℃）；

② outdoor ambient temperature T_oaN +2 (deg.c) (2 ℃ return difference, default 4+2 deg.c);

and thirdly, the outdoor compressor is closed.

As described above, in the above-mentioned auxiliary electric heating condition, if there are 2 outdoor units, the outdoor ambient temperature is the average value of the ambient temperatures of the 2 outdoor units, i.e., T_oa=(T_oa1+T_oa2)/2。

Second, defrosting state

After entering the defrosting process, detecting the operation state of the auxiliary electric heating:

firstly, if the auxiliary electric heating is in a closed state, the auxiliary electric heating is started; if the auxiliary electric heating is in the running state, continuing to keep running;

secondly, during defrosting, the auxiliary electric heating is operated all the time without detecting the closing condition;

after defrosting is finished, if a shutdown signal in defrosting is received, the auxiliary electric heating is immediately turned off, otherwise, whether the auxiliary electric heating needs to be turned off is judged according to the auxiliary electric heating turn-off condition in the normal running state.

As can be seen from the above, the conventional method for controlling auxiliary electric heating only controls the on and off of the auxiliary electric heating according to some temperature conditions, and does not consider energy saving, so that the auxiliary electric heating is also frequently turned on and operated under some working conditions that are not necessary to use, which reduces the service life of the auxiliary electric heating equipment, and the energy efficiency ratio of the auxiliary electric heating is generally much smaller than that of the compressor, which also causes energy waste, so that the energy efficiency ratio is relatively low; further, the auxiliary electric heating apparatus, which is frequently operated for a long time, also causes a high failure rate.

Disclosure of Invention

The embodiment of the invention provides a method for controlling auxiliary electric heating in a multi-split air-conditioning system, which improves the energy efficiency ratio of the multi-split air-conditioning system.

The embodiment of the invention also provides a device for controlling auxiliary electric heating in the multi-split air-conditioning system, which improves the energy efficiency ratio of the multi-split air-conditioning system.

In order to achieve the above object, an embodiment of the present invention provides a method for controlling auxiliary electric heating in a multi-split air conditioning system, including:

acquiring rated heating capacity information and rated power consumption information of each compressor running in the multi-split air-conditioning system during heating operation;

acquiring rated auxiliary electric heating quantity information, rated auxiliary electric power consumption information and rated heating demand information of an indoor unit containing auxiliary electric heating;

selecting a compressor, the operating frequency of the compressor and an indoor unit containing auxiliary electric heating, adding the sum of the rated heating capacity of the selected compressor and the sum of the rated auxiliary electric heating capacity of the indoor unit containing auxiliary electric heating to ensure that the sum obtained by adding is not less than the sum of the rated heating demand of the selected indoor unit containing auxiliary electric heating, and ensuring that the sum of the power consumption of the selected compressor and the sum of the power consumption of the indoor unit containing auxiliary electric heating is minimum.

Further comprising:

acquiring running time information of each compressor;

counting the compressors meeting the preset running time condition, and adjusting the rated power consumption of the compressors according to the preset adjustment amount corresponding to the running time condition;

and according to the adjustment of the rated power consumption, reselecting the compressor and the indoor unit containing the auxiliary electric heating, adding the sum of the rated heating capacity of the selected compressor and the sum of the rated auxiliary electric heating capacity of the indoor unit containing the auxiliary electric heating, enabling the sum obtained by adding to be not less than the sum of the rated heating demand of the selected indoor unit containing the auxiliary electric heating, and enabling the sum of the power consumption of the selected compressor and the indoor unit containing the auxiliary electric heating to be minimum.

The runtime conditions include: one or any combination of a cumulative compressor run time condition, a compressor run time continuous condition, and a run time difference between the compressor run time continuous and a shortest run time continuous within the system.

The cumulative run time conditions for the compressor include: a first run time sub-condition threshold to a fourth run time sub-condition threshold; the adjusting the rated power consumption of the compressor according to the preset adjustment amount corresponding to the running time condition comprises the following steps:

if the difference between the accumulated running time of the compressor and the shortest accumulated running time in the system is larger than a first running time sub-condition threshold value and smaller than a second running time sub-condition threshold value, the rated power consumption of the compressor under each working condition is adjusted up to a preset first percentage threshold value;

if the difference between the accumulated running time of the compressor and the shortest accumulated running time in the system is greater than or equal to the second running time sub-condition threshold value and less than the third running time sub-condition threshold value, the rated power consumption of the compressor under each working condition is adjusted up to a preset second percentage threshold value;

if the difference between the accumulated running time of the compressor and the shortest accumulated running time in the system is greater than or equal to the third running time sub-condition threshold value and less than the fourth running time sub-condition threshold value, the rated power consumption of the compressor under each working condition is adjusted up to a preset third percentage threshold value;

and if the difference between the accumulated running time of the compressor and the shortest accumulated running time in the system is greater than or equal to a fourth running time sub-condition threshold value, the rated power consumption of the compressor under each working condition is adjusted up to a preset fourth percentage threshold value.

Adding the sum of the rated heating capacities of the selected compressors and the sum of the rated auxiliary electric heating capacities of the indoor units including auxiliary electric heating to make the sum obtained by adding not less than the sum of the rated heating demands of the selected indoor units including auxiliary electric heating, and making the sum of the power consumption of the selected compressors and the power consumption of the indoor units including auxiliary electric heating minimum comprises:

respectively acquiring a compressor state matrix, a compressor rated heating capacity matrix and a compressor rated power consumption matrix which are composed of compressor state parameters;

dividing the compressor state matrix into a plurality of compressor state sub-matrixes by taking the compressor state parameters as variables, and multiplying the divided sub-matrixes by the compressor rated heating capacity matrix to obtain the sum of the rated heating capacities of the compressors to be selected;

respectively acquiring an indoor unit state matrix, an indoor unit rated auxiliary electric heating quantity matrix and an indoor unit rated auxiliary electric power consumption quantity matrix, wherein the indoor unit state matrix consists of indoor unit state parameters containing auxiliary electric heating;

dividing the indoor unit state matrix into a plurality of indoor unit state sub-matrixes by taking the indoor unit state parameters as variables, and multiplying the divided sub-matrixes by the indoor unit rated auxiliary electric heating quantity matrix to obtain the sum of the rated auxiliary electric heating quantities of the indoor units to be selected;

adding the sum of the rated heating amounts of the obtained compressors and the sum of the rated auxiliary electric heating amounts of the indoor units containing auxiliary electric heating to obtain a compressor state sub-matrix and an indoor unit state sub-matrix which correspond to the sum of the added rated heating amounts and are not less than the sum of the rated heating amounts;

calculating the product of the obtained compressor state sub-matrix and the compressor rated power consumption matrix, and the product of the indoor unit state sub-matrix and the indoor unit rated auxiliary power consumption matrix, and adding to obtain corresponding power consumption;

and acquiring a compressor state sub-matrix and an indoor unit state sub-matrix corresponding to the minimum power consumption, selecting a compressor with a compressor state of 1 in the compressor state sub-matrix and an indoor unit with an indoor unit state of 1 in the indoor unit state sub-matrix.

Calculating the sum of the sum obtained by adding is not less than the sum of the rated heating demand of the selected indoor unit containing the auxiliary electric heating, and the function formula which enables the sum of the power consumption of the selected compressor and the selected indoor unit containing the auxiliary electric heating to be minimum is as follows:

<math> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <munderover> <mi>Σ</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>m</mi> </munderover> <mrow> <mo>(</mo> <msubsup> <mi>b</mi> <mi>i</mi> <mo>′</mo> </msubsup> <mo>+</mo> <msubsup> <mi>b</mi> <mi>i</mi> <mrow> <mo>′</mo> <mo>′</mo> </mrow> </msubsup> <mo>)</mo> </mrow> <mo>=</mo> <munderover> <mi>Σ</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>m</mi> </munderover> <mrow> <mo>(</mo> <mrow> <mo>(</mo> <munderover> <mi>Σ</mi> <mrow> <mi>j</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <msub> <mi>x</mi> <mi>ij</mi> </msub> <msub> <mi>D</mi> <mi>ij</mi> </msub> <mo>)</mo> </mrow> <mo>+</mo> <msub> <mi>x</mi> <mi>i</mi> </msub> <msub> <mi>D</mi> <mi>i</mi> </msub> <mo>)</mo> </mrow> <mo>&GreaterEqual;</mo> <munderover> <mi>Σ</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>m</mi> </munderover> <msub> <mi>B</mi> <mi>i</mi> </msub> </mtd> </mtr> <mtr> <mtd> <mi>MinZ</mi> <mo>=</mo> <munderover> <mi>Σ</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>m</mi> </munderover> <mrow> <mo>(</mo> <msubsup> <mi>z</mi> <mi>i</mi> <mo>′</mo> </msubsup> <mo>+</mo> <msubsup> <mi>z</mi> <mi>i</mi> <mrow> <mo>′</mo> <mo>′</mo> </mrow> </msubsup> <mo>)</mo> </mrow> <mo>=</mo> <munderover> <mi>Σ</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>m</mi> </munderover> <mrow> <mo>(</mo> <mrow> <mo>(</mo> <munderover> <mi>Σ</mi> <mrow> <mi>j</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <msub> <mi>x</mi> <mi>ij</mi> </msub> <msub> <mi>C</mi> <mi>ij</mi> </msub> <mo>)</mo> </mrow> <mo>+</mo> <msub> <mi>x</mi> <mi>i</mi> </msub> <msub> <mi>C</mi> <mi>i</mi> </msub> <mo>)</mo> </mrow> </mtd> </mtr> </mtable> </mfenced> </math>

in the formula,

m is the larger of the number of compressors and the number of indoor units containing auxiliary electric heating in the multi-split air conditioning system;

b＇_ithe rated heating capacity of the ith compressor;

b″_irated auxiliary electric heating quantity of an ith indoor unit containing auxiliary electric heating;

n is the maximum rated working condition number of each compressor in the multi-split air conditioning system;

x_ijthe j operation state of the ith compressor;

D_ijrated heating capacity output by the ith compressor under the jth working condition;

x_ithe state of the ith indoor unit containing auxiliary electric heating is shown;

D_irated auxiliary electric heating quantity of an ith indoor unit containing auxiliary electric heating;

B_irated heating demand of the ith indoor unit containing auxiliary electric heating;

z′_irated power consumption of the ith compressor;

z″_iis a bagRated auxiliary power consumption of the ith indoor unit containing auxiliary electric heating is x_ij=1，z″_i=C_i；

C_ijRated power consumption of the ith compressor under the jth working condition;

wherein,

x_ije {0,1} and

and, x_i∈{0,1}。

The rated heating capacity matrix calculation formula of the ith compressor is as follows:

the rated power consumption matrix calculation formula corresponding to the rated heating capacity of the ith compressor is as follows:

calculating the sum obtained by adding is not less than the sum of the rated heating demand of the selected indoor unit containing the auxiliary electric heating, and the matrix formula which enables the sum of the power consumption of the selected compressor and the power consumption of the indoor unit containing the auxiliary electric heating to be minimum is as follows:

wherein,

is a compressor state matrix, x, in a multi-split air conditioning system_ijIs a state parameter;

a rated heating capacity matrix is set for a compressor in the multi-split air conditioning system;

and the rated power consumption matrix is a compressor in the multi-split air conditioning system.

An apparatus for controlling auxiliary electric heating in a multi-split air conditioning system, the apparatus comprising: a first parameter obtaining module, a second parameter obtaining module and a selecting module, wherein,

the system comprises a first parameter acquisition module, a selection module and a second parameter acquisition module, wherein the first parameter acquisition module is used for acquiring rated heating capacity information and rated power consumption information of each compressor in the multi-split air conditioning system during heating operation and outputting the information to the selection module;

the second parameter acquisition module is used for acquiring rated auxiliary electric heating quantity information, rated auxiliary electric power consumption information and rated heating demand information of the indoor unit containing auxiliary electric heating and outputting the information to the selection module;

and the selecting module is used for selecting the compressor, the operating frequency of the compressor and the indoor unit containing auxiliary electric heating, adding the sum of the rated heating capacity of the selected compressor and the sum of the rated auxiliary electric heating capacity of the indoor unit containing auxiliary electric heating, enabling the sum obtained by adding to be not less than the sum of the rated heating demand of the selected indoor unit containing auxiliary electric heating, and enabling the sum of the power consumption of the selected compressor and the power consumption of the indoor unit containing auxiliary electric heating to be minimum.

Further comprising: a third parameter obtaining module and an adjusting module, wherein,

the third parameter acquisition module is used for acquiring the running time information of each compressor and outputting the running time information to the adjustment module;

and the adjusting module is used for counting the compressors meeting the preset running time condition according to the output of the third parameter acquiring module, adjusting the rated power consumption of the compressors acquired in the first parameter acquiring module according to the preset adjusting amount corresponding to the running time condition, and triggering the selecting module to reselect.

The selecting module comprises: a first parameter matrix obtaining unit, a second parameter matrix obtaining unit, a first splitting unit, a second splitting unit, a first calculating unit, a second calculating unit, a summing unit, a comparing unit, a power consumption calculating unit and a selecting unit,

the system comprises a first parameter matrix acquisition unit, a second parameter matrix acquisition unit and a control unit, wherein the first parameter matrix acquisition unit is used for respectively acquiring a compressor state matrix, a compressor rated heating quantity matrix and a compressor rated power consumption matrix which are composed of compressor state parameters;

the second parameter matrix acquisition unit is used for respectively acquiring an indoor unit state matrix, an indoor unit rated auxiliary electric heating quantity matrix and an indoor unit rated auxiliary electric power consumption quantity matrix, wherein the indoor unit state matrix consists of indoor unit state parameters containing auxiliary electric heating;

the first splitting unit is used for splitting the compressor state matrix into a plurality of compressor state sub-matrixes by taking the compressor state as a variable and outputting the compressor state sub-matrixes to the first computing unit;

the second splitting unit is used for splitting the indoor unit state matrix into a plurality of indoor unit state sub-matrixes by taking the indoor unit state parameters as variables and outputting the indoor unit state sub-matrixes to the second calculating unit;

the first calculating unit is used for multiplying the split compressor state sub-matrix and the compressor rated heating capacity matrix to obtain the sum of the rated heating capacities of the compressors to be selected and outputting the sum to the summing unit;

the second calculation unit is used for multiplying the split indoor unit state sub-matrix and the indoor unit rated auxiliary electric heating quantity matrix to obtain the sum of the rated auxiliary electric heating quantities of the indoor units to be selected and outputting the sum to the summation unit;

the summing unit is used for summing the sum of the received rated heating capacities of the compressors and the sum of the rated auxiliary electric heating capacities of the indoor units and outputting the sum to the comparing unit;

the comparison unit is used for acquiring a compressor state sub-matrix and an indoor unit state sub-matrix corresponding to the sum of the sum;

the power consumption calculating unit is used for calculating the product of the obtained compressor state sub-matrix and the compressor rated power consumption matrix and the product of the indoor unit state sub-matrix and the indoor unit rated auxiliary power consumption matrix, and adding the products to obtain corresponding power consumption;

and the selecting unit is used for acquiring the compressor state sub-matrix and the indoor unit state sub-matrix corresponding to the minimum power consumption, selecting the compressor with the compressor state of 1 in the compressor state sub-matrix, and selecting the indoor unit with the indoor unit state of 1 in the indoor unit state sub-matrix.

The adjustment module includes: a threshold value storage unit, a judgment unit and an adjustment unit, wherein,

a threshold value storage unit, configured to store a preset first run-time sub-condition threshold value, a preset second run-time sub-condition threshold value, a preset third run-time sub-condition threshold value, and a preset fourth run-time sub-condition threshold value;

a judging unit outputting first adjustment information to the adjusting unit if an operation time difference between the accumulated operation time of the compressor and the shortest accumulated operation time in the system is greater than a first operation time sub-condition threshold value and less than a second operation time sub-condition threshold value;

outputting second adjustment information to the adjustment unit if a difference between the accumulated operating time of the compressor and the shortest accumulated operating time in the system is greater than or equal to a second operating time sub-condition threshold value and less than a third operating time sub-condition threshold value;

outputting third adjustment information to the adjustment unit if an operating time difference between the accumulated operating time of the compressor and the shortest accumulated operating time in the system is greater than or equal to a third operating time sub-condition threshold value and less than a fourth operating time sub-condition threshold value;

outputting fourth adjustment information to the adjustment unit if the difference between the accumulated running time of the compressor and the shortest accumulated running time in the system is greater than or equal to a fourth running time sub-condition threshold;

the adjusting unit is used for receiving first adjusting information and adjusting the rated power consumption of the compressor under each working condition to a preset first percentage threshold; receiving second adjustment information, and adjusting the rated power consumption of the compressor under each working condition to a preset second percentage threshold; receiving third adjustment information, and adjusting the rated power consumption of the compressor under each working condition to a preset third percentage threshold; and receiving fourth adjustment information, and adjusting the rated power consumption of the compressor under each working condition to a preset fourth percentage threshold.

According to the technical scheme, the method and the device for controlling the auxiliary electric heating, provided by the embodiment of the invention, are used for acquiring the rated heating capacity information and the rated power consumption information of each compressor running in the multi-split air-conditioning system during heating operation; acquiring rated auxiliary electric heating quantity information, rated auxiliary electric power consumption information and rated heating demand information of an indoor unit containing auxiliary electric heating; selecting a compressor and an indoor unit containing auxiliary electric heating, adding the sum of the rated heating capacity of the selected compressor and the sum of the rated auxiliary electric heating capacity of the indoor unit containing auxiliary electric heating, enabling the sum obtained by adding to be not less than the sum of the rated heating demand of the selected indoor unit containing auxiliary electric heating, and enabling the sum of the power consumption of the selected compressor and the sum of the power consumption of the indoor unit containing auxiliary electric heating to be minimum. Therefore, the optimal heating combination calculation of the system is carried out by considering the heating quantity provided by the outdoor unit and the auxiliary electric heating, and the energy efficiency ratio of the multi-split air-conditioning system is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It is to be understood that the drawings in the following description are merely exemplary of the invention and that other embodiments and drawings may be devised by those skilled in the art based on the exemplary embodiments shown in the drawings.

Fig. 1 is a schematic flow chart of a method for controlling auxiliary electric heating according to an embodiment of the present invention.

Fig. 2 is a schematic flow chart illustrating the control of the auxiliary electric heating according to the embodiment of the present invention.

Fig. 3 is a schematic structural diagram of a device for controlling auxiliary electric heating according to an embodiment of the present invention.

Detailed Description

The technical solutions of the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings, and it is to be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

With the increasing emphasis of the country on energy conservation and emission reduction, users pay more and more attention to energy efficiency ratio indexes reflecting the comprehensive performance of the multi-split air-conditioning system, namely, under rated working conditions and specified conditions, the ratio of the output quantity to the input power of the multi-split air-conditioning system is larger, and the energy efficiency ratio indicates that the multi-split air-conditioning system is more energy-saving. The conventional method for controlling the auxiliary electric heating only controls the on and off of the auxiliary electric heating according to some temperature conditions, the energy efficiency ratio of the auxiliary electric heating is generally far smaller than that of a compressor, the problems of the heat supply quantity which can be provided by the compressor and the energy efficiency ratio of a system are not considered, and the energy efficiency ratio has a large difference from the level which can be reached by an air conditioner, so that the auxiliary electric heating can be operated for a long time, the energy is wasted, and the energy efficiency is low. In the embodiment of the invention, the indoor unit or the water module containing the auxiliary electric heating equipment is used as a special outdoor unit, and the heat supply provided by the outdoor unit and the auxiliary electric heating is comprehensively considered to perform the optimal heating combination calculation of the system. The auxiliary electric heating is started only when the heat supply of the compressor is insufficient, so that the frequency of using the auxiliary electric heating is reduced, the operation parameters of the system are optimized through the optimized combination of a plurality of operation units of the indoor unit and the outdoor unit, the effect of maximally exerting the system performance is achieved, the system is more energy-saving, the actual energy efficiency ratio of the system is improved, and the problem of optimizing and controlling the auxiliary electric heating of the multi-split air conditioning system of the water multi-split module type unit is solved.

Fig. 1 is a schematic flow chart of a method for controlling auxiliary electric heating according to an embodiment of the present invention. Referring to fig. 1, the process includes:

step 101, obtaining rated heating capacity information and rated power consumption information of each compressor running in a multi-split air conditioning system;

in this step, the acquired process is executed during heating operation, and the multi-split air conditioning system includes a plurality of compressors, each of which has a different rated heating capacity under different operating conditions, but in a certain operating period, the operating condition of the compressor is determined and has a determined rated heating capacity.

In the embodiment of the invention, in the multi-split air conditioning system, the state of the ith compressor in operation under the jth working condition is set as x_ijAnd is provided with x_ijWhen 1, it means that the compressor is in operation state under the working condition, i.e. in starting state, x_ijWhen the value is 0, the compressor is in a stop state under the working condition, namely in a shutdown state.

In practical applications, the compressor is in either an on state or an off state at any time. State x when the compressor is in j operating mode_ijWhen the value is 1, the running state is indicated, and the corresponding rated heating quantity D is output_ijAnd, generating a corresponding rated power consumption C_ijAnd for other conditions, the state x of the compressor_ijA value of 0 indicates that the compressor is in a shutdown state. That is, the compressor can have a rated heating capacity only when it is in the on state.

Then, the rated heating capacity of the ith compressor and the rated power consumption corresponding to the rated heating capacity are expressed by a functional expression, that is, the functional expression of the rated heating capacity information and the rated power consumption information of the compressor is as follows:

wherein,

<math> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <msub> <mi>x</mi> <mi>ij</mi> </msub> <mo>&Element;</mo> <mo>{</mo> <mn>0,1</mn> <mo>}</mo> </mtd> </mtr> <mtr> <mtd> <munderover> <mi>Σ</mi> <mrow> <mi>j</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>k</mi> </munderover> <msub> <mi>x</mi> <mi>ij</mi> </msub> <mo>=</mo> <msub> <mi>a</mi> <mi>i</mi> </msub> <mo>≤</mo> <mn>1</mn> </mtd> </mtr> </mtable> </mfenced> </math>

in the formula,

x_ijis the j operation state of the i compressor, i.e. the j operation frequency (or rotation speed) x of the compressor_ij=0 or x_ij=1；

a_iFor compression of the ith stageThe state of the machine, being an integer and less than or equal to 1, a_iIs 1 indicates that the compressor is in the on state, a_iA value of 0 indicates that the compressor is in a shutdown state, namely the compressor is in a startup state under various working conditions, at most one working condition;

b′_irated heating capacity of the ith compressor, and rated heating capacity of the ith compressor is D under the jth working condition_ijx_ij；

And k is the rated working condition number of the ith compressor in operation in the multi-split air conditioning system, and each rated working condition corresponds to a rated heating capacity and rated power consumption. For example, if compressor a has a rated number of operating conditions of 7, k = 7; if the rated working condition number of the compressor B is 8, k = 8; if the rated working condition number of the compressor C is 1, k = 1;

z′_irated power consumption of the ith compressor is C_ijx_ij。

Accordingly, the rated heating capacity of the ith compressor and the rated power consumption corresponding to the rated heating capacity are expressed by a matrix as follows:

102, acquiring rated auxiliary electric heating quantity information, rated auxiliary electric power consumption information and rated heating demand information of an indoor unit containing auxiliary electric heating;

in this step, the rated auxiliary power heating amount information, the rated auxiliary power consumption amount information, and the rated heating demand amount information are heating parameter information.

Under the condition that the heat supply amount of the compressor is insufficient, the heat supply amount generated when the indoor unit comprising the auxiliary electric heating operates is taken into consideration, the heat supply amount provided by the outdoor unit and the auxiliary electric heating is comprehensively considered, and the optimal heating combination calculation of the system is carried out. Therefore, the running parameters of the system are optimized through the optimized combination of the plurality of running units of the indoor unit and the outdoor unit, the auxiliary electric heating is started when the heat supply of the compressor is insufficient, the frequency of using the auxiliary electric heating can be reduced, and the use frequency of the auxiliary electric heating with low energy efficiency is reduced.

Setting the state of the ith indoor unit containing auxiliary electric heating as x_i，x_iWhen the number is 1, the auxiliary electric heating of the indoor unit is started, and the rated heating demand is B_iCorresponding to the output of rated auxiliary electric heating quantity e_iI.e. the heating capacity of the auxiliary electric heating inside the indoor unit or the water module, the consumed electric quantity is the rated auxiliary electric power consumption C_i；x_iAnd when the value is 0, the auxiliary electric heating of the indoor unit is turned off.

Then, the heating parameter information of the indoor unit including the auxiliary electric heating is expressed by a functional formula as follows:

in the formula,

x_ithe state of the i-th indoor unit including auxiliary electric heating, x_ij=0 or x_ij=1；

z″_irated auxiliary power consumption of the ith indoor unit containing auxiliary electric heating is as x_ij=1，z″_i=C_i；

h_iThe actual heating demand of the i-th indoor unit containing the auxiliary electric heating.

The heating parameter information of the indoor unit can be obtained from the related technical data provided by the multi-split air conditioning system.

And 103, selecting a compressor and an indoor unit containing auxiliary electric heating, adding the sum of the rated heating capacity of the selected compressor and the sum of the rated auxiliary electric heating capacity of the indoor unit containing auxiliary electric heating, enabling the sum obtained by adding to be not less than the sum of the rated heating demand of the selected indoor unit containing auxiliary electric heating, and enabling the sum of the power consumption of the selected compressor and the sum of the power consumption of the indoor unit containing auxiliary electric heating to be minimum.

In this step, the compressor and its operating frequency are selected. The sum obtained by adding is not less than the sum of the rated heating demands of the selected indoor unit comprising auxiliary electric heating, and the sum of the power consumptions of the selected compressor and the selected indoor unit comprising auxiliary electric heating is minimized, which can be solved by constructing the following function group:

<math> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <mi>b</mi> <mo>=</mo> <munderover> <mi>Σ</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>m</mi> </munderover> <mrow> <mo>(</mo> <msubsup> <mi>b</mi> <mi>i</mi> <mo>′</mo> </msubsup> <mo>+</mo> <msubsup> <mi>b</mi> <mi>i</mi> <mrow> <mo>′</mo> <mo>′</mo> </mrow> </msubsup> <mo>)</mo> </mrow> <mo>=</mo> <munderover> <mi>Σ</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>m</mi> </munderover> <mrow> <mo>(</mo> <mrow> <mo>(</mo> <munderover> <mi>Σ</mi> <mrow> <mi>j</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <msub> <mi>x</mi> <mi>ij</mi> </msub> <msub> <mi>D</mi> <mi>ij</mi> </msub> <mo>)</mo> </mrow> <mo>+</mo> <msub> <mi>x</mi> <mi>i</mi> </msub> <msub> <mi>D</mi> <mi>i</mi> </msub> <mo>)</mo> </mrow> <mo>&GreaterEqual;</mo> <munderover> <mi>Σ</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>m</mi> </munderover> <msub> <mi>B</mi> <mi>i</mi> </msub> </mtd> </mtr> <mtr> <mtd> <mi>MinZ</mi> <mo>=</mo> <munderover> <mi>Σ</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>m</mi> </munderover> <mrow> <mo>(</mo> <msubsup> <mi>z</mi> <mi>i</mi> <mo>′</mo> </msubsup> <mo>+</mo> <msubsup> <mi>z</mi> <mi>i</mi> <mrow> <mo>′</mo> <mo>′</mo> </mrow> </msubsup> <mo>)</mo> </mrow> <mo>=</mo> <munderover> <mi>Σ</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>m</mi> </munderover> <mrow> <mo>(</mo> <mrow> <mo>(</mo> <munderover> <mi>Σ</mi> <mrow> <mi>j</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <msub> <mi>x</mi> <mi>ij</mi> </msub> <msub> <mi>C</mi> <mi>ij</mi> </msub> <mo>)</mo> </mrow> <mo>+</mo> <msub> <mi>x</mi> <mi>i</mi> </msub> <msub> <mi>C</mi> <mi>i</mi> </msub> <mo>)</mo> </mrow> </mtd> </mtr> </mtable> </mfenced> </math>

in the formula,

n is the maximum rated operating condition (heating capacity) number of each compressor in the multi-split air conditioning system, for example, as described above, if the compressor a has the rated heating capacity of 7, the compressor B has the rated heating capacity of 8, and the compressor C has the rated heating capacity of 1, then n = 8;

m is the larger of the number of compressors and the number of indoor units containing auxiliary electric heating in the multi-split air conditioning system.

In the set of functions, C_ij、C_i、D_ij、D_iAnd B_iIs a constant value, x_ijAnd x_iIs a variable, satisfies x_ijE {0,1} and

and, x_i∈{0,1}。

Obtaining variable x by solving the above function set_ijI corresponding to 1 is obtained, and a variable x is obtained for the ith compressor which is finally selected_ijIs equal to 1 hourCorresponding j is the corresponding running state, namely the corresponding frequency or rotating speed, when the ith compressor which is finally selected runs, and after the working condition is obtained, the rated heating capacity information and the rated power consumption information which correspond to the working condition can be obtained; obtaining a variable x_iAnd i corresponding to 1 is the ith machine which is finally selected and contains auxiliary electric heating, namely the auxiliary electric heating of the ith machine needs to be started.

The function group is expressed by adopting a matrix, and the expression is as follows:

wherein,

Adding the sum of the rated heating capacities of the selected compressors and the sum of the rated auxiliary heating capacities of the indoor units including auxiliary electric heating to make the sum obtained by adding be not less than the sum of the rated heating demands of the selected indoor units including auxiliary electric heating, and making the sum of the power consumption of the selected compressors and the sum of the power consumption of the indoor units including auxiliary electric heating minimum can specifically include:

a11, respectively acquiring a compressor state matrix, a compressor rated heating capacity matrix and a compressor rated power consumption matrix which are composed of compressor state parameters;

a12, dividing a compressor state matrix into a plurality of compressor state sub-matrixes by taking a compressor state parameter as a variable, and multiplying the divided sub-matrixes by a compressor rated heating capacity matrix to obtain the sum of rated heating capacities of the compressors to be selected;

in this step, in the compressor state matrix, the state of each compressor under any working condition changes, and a compressor state sub-matrix is correspondingly formed. Thus, if the i-th compressor has a rated heat capacity of A_iAnd the multi-split air conditioning system comprises L compressors, and the quantity B of the state sub-matrixes of the compressors which are formed in total is as follows:

a13, respectively acquiring an indoor unit state matrix, an indoor unit rated auxiliary power heating quantity matrix and an indoor unit rated auxiliary power consumption quantity matrix, wherein the indoor unit state matrix consists of indoor unit state parameters containing auxiliary electric heating;

a14, taking the indoor unit state parameters as variables, splitting the indoor unit state matrix into a plurality of indoor unit state sub-matrices, and multiplying the split sub-matrices by the indoor unit rated auxiliary electric heating quantity matrix to obtain the sum of the rated auxiliary electric heating quantities of the indoor units to be selected;

the flow performed in this step is similar to step a 12.

A15, adding the sum of the rated heating capacity of the obtained compressor and the sum of the rated auxiliary electric heating capacity of the indoor unit containing auxiliary electric heating to obtain a compressor state sub-matrix and an indoor unit state sub-matrix, wherein the sum of the obtained sums is not less than the sum of the rated heating demand;

a16, calculating the product of the obtained compressor state sub-matrix and the compressor rated power consumption matrix, and the product of the indoor unit state sub-matrix and the indoor unit rated auxiliary power consumption matrix, and adding to obtain corresponding power consumption;

a17, obtaining a compressor state sub-matrix and an indoor unit state sub-matrix corresponding to the minimum power consumption, selecting a compressor with a compressor state of 1 in the compressor state sub-matrix and an indoor unit with an indoor unit state of 1 in the indoor unit state sub-matrix.

Therefore, through calculation of the optimal combination, the auxiliary electric heating is actually controlled to be turned on only when the heat supply of the compressor is insufficient, so that the use of the auxiliary electric heating (auxiliary electricity) is reduced, and the system is more energy-saving; meanwhile, the auxiliary electric heating in the indoor unit (or the water module) is used as a special outdoor unit to participate in the calculation of the optimal combination, and the optimization algorithm can adapt to the condition that the auxiliary electric heating is forcibly opened by other conditions.

In summary, the constraint words of the upper matrix are described as follows:

each compressor (press) can only operate in one operating condition (frequency): in the state matrix of the compressor, the sum of the state parameter values of each row is 1 or 0;

the sum of the rated heating quantity output by the compressor and the rated auxiliary electric heating quantity output by the auxiliary electric heating is greater than or equal to the rated heating demand;

and thirdly, in the state matrix of the compressor and the state matrix of the indoor unit, each state parameter is binary, namely, for each press, the compressor is started or shut down.

In the above matrix, if the rated heating amount of a certain compressor is less than the maximum rated heating amount, the position in the corresponding matrix is filled with 0.

The solution can be calculated by software programming, and can also be simulated by excel.

In practical application, if the operation time of the compressor is too long, not only the service life of each compressor in the multi-split air conditioning system is not uniform, which affects the reliability of the whole multi-split air conditioning system, but also the performance of the compressor is reduced. In the embodiment of the invention, the running time of the compressors is further controlled in the multi-split air-conditioning system, when the running time of the compressors exceeds a preset time threshold value or the running time difference with the compressor with the shortest running time in the system exceeds a preset time difference threshold value, the multi-split air-conditioning system is triggered to carry out optimization processing again, and the compressor with longer running time is placed in a shutdown state, so that the running compressors are reselected, and the running time of each compressor tends to be balanced. Thus, the method further comprises:

104, acquiring running time information of each compressor;

in this step, the running time information of the compressor in the working state may be counted once a day according to a preset time period, for example.

Step 105, counting the compressors meeting the preset running time condition, and adjusting the rated power consumption of the compressors according to the preset adjustment amount corresponding to the running time condition;

in this step, the operation time condition may be an accumulated operation time condition of the compressor, a continuous operation time condition of the compressor, or an operation time difference condition between the continuous operation time of the compressor and the shortest continuous operation time in the system. Of course, in practical applications, the operation time condition may be set in other manners, such as an operation time difference condition between the continuous operation time of the compressor and the average continuous operation time of each compressor in the system, or any combination of the above settings.

For each runtime condition, preferably, multiple runtime sub-condition thresholds may be set. For example, for the case where the accumulated operation time of the compressor is taken as the operation time condition, four operation time sub-condition thresholds are set, respectively 100 hours, 200 hours, 300 hours, and 400 hours. Then:

if the difference between the accumulated running time of the compressor and the shortest accumulated running time in the system is larger than 100 hours and smaller than 200 hours, a first running time sub-condition threshold value is met, the adjustment amount corresponding to the first running time sub-condition threshold value is set to be (10 +/-1)% of the compressor, and then the rated power consumption of the compressor under each working condition is adjusted up to a preset first percentage threshold value;

if the difference between the accumulated running time of the compressor and the shortest accumulated running time in the system is greater than or equal to 200 hours and less than 300 hours, a second running time sub-condition threshold value is met, the adjustment amount corresponding to the second running time sub-condition threshold value is set to be (20 +/-2)% of the compressor, and then the rated power consumption of the compressor under each working condition is adjusted up to a preset second percentage threshold value;

if the difference between the accumulated running time of the compressor and the shortest accumulated running time in the system is greater than or equal to 300 hours and less than 400 hours, a third running time sub-condition threshold value is met, the adjustment amount corresponding to the third running time sub-condition threshold value is set to be (30 +/-3)% of the compressor, namely the rated power consumption of the compressor under each working condition is adjusted up to a preset third percentage threshold value;

and if the difference between the accumulated running time of the compressor and the running time of the shortest accumulated running time in the system is greater than or equal to 400 hours, a fourth running time sub-condition threshold value is met, the adjustment amount corresponding to the fourth running time sub-condition threshold value is set to be (50 +/-5)% of the compressor, and the rated power consumption of the compressor under each working condition is adjusted up to a preset fourth percentage threshold value.

And 106, reselecting the compressor and the indoor unit containing the auxiliary electric heating according to the adjustment of the rated power consumption, adding the sum of the rated heating capacity of the selected compressor and the sum of the rated auxiliary electric heating capacity of the indoor unit containing the auxiliary electric heating, enabling the sum obtained by adding to be not less than the sum of the rated heating demand of the selected indoor unit containing the auxiliary electric heating, and enabling the sum of the power consumption of the selected compressor and the sum of the power consumption of the indoor unit containing the auxiliary electric heating to be minimum.

The execution flow of this step is the same as that of step 103, and let' z_iFor the ith compressor adjusted by rated power consumption at a_iRated power consumption of the compressor in the j operating mode is (C)_ij+ΔC_ij)x_ijWherein, Δ C_ijFor the adjusted nominal power consumption parameter, Δ C, for example, for the compressor satisfying the first operating time sub-condition threshold value_ij=0.1C_ij。

Thus, the solution is performed by reconstructing the following set of functions:

through the function group solution, the probability that the compressor with longer running time (continuous running time and accumulated running time) is reselected is smaller, so that each compressor realizes balanced running, the condition that some compressors are in a starting state for a long time and other compressors are in a shutdown state for a long time is avoided, and the service life of each compressor is balanced; meanwhile, the multi-split air-conditioning system is more energy-saving, the operation parameters of the multi-split air-conditioning system are optimized, the heating capacity of the multi-split air-conditioning system is fully exerted, the power consumption of the multi-split air-conditioning system is minimized, the energy waste is effectively reduced, and the energy efficiency ratio of the system is improved.

The corresponding matrix expression is:

wherein,

and the matrix is the rated power consumption of the adjusted compressor in the multi-split air conditioning system.

Fig. 2 is a schematic flow chart illustrating the control of the auxiliary electric heating according to the embodiment of the present invention. Referring to fig. 2, the process includes:

step 201, judging whether a preset starting auxiliary electric heating condition in the multi-split air conditioning system is met, if so, executing step 202, otherwise, executing step 206;

in this step, the opening auxiliary electrical heating condition refers to an opening auxiliary electrical heating condition set in the prior art.

Step 202, judging whether the heating capacity of the compressor is sufficient, if so, executing step 203, otherwise, executing step 204;

in the step, whether the heating capacity of the compressor in the multi-split air-conditioning system is sufficient or not is judged according to the calculation result through the calculation of the optimal combination.

Step 203, judging whether the forced opening condition is met, if so, executing step 204, otherwise, executing step 206;

in this step, the forced turn-on condition may be set in the prior art.

Step 204, starting auxiliary electric heating;

step 205, judging whether a preset auxiliary electric heating condition for closing in the multi-split air conditioning system is met, if so, executing step 206, otherwise, returning to execute step 204;

and step 206, turning off the auxiliary electric heating, and returning to execute the step 201 when the next preset time period is up.

Fig. 3 is a schematic structural diagram of a device for controlling auxiliary electric heating according to an embodiment of the present invention. Referring to fig. 3, the apparatus includes: a first parameter obtaining module, a second parameter obtaining module and a selecting module, wherein,

and the selecting module is used for selecting the compressor and the indoor unit containing the auxiliary electric heating, adding the sum of the rated heating capacity of the selected compressor and the sum of the rated auxiliary electric heating capacity of the indoor unit containing the auxiliary electric heating, enabling the sum obtained by adding to be not less than the sum of the rated heating demand of the selected indoor unit containing the auxiliary electric heating, and enabling the sum of the power consumption of the selected compressor and the sum of the power consumption of the indoor unit containing the auxiliary electric heating to be minimum.

Preferably, the apparatus further comprises: a third parameter obtaining module and an adjusting module, wherein,

Wherein,

the selecting module comprises: a first parameter matrix obtaining unit, a second parameter matrix obtaining unit, a first splitting unit, a second splitting unit, a first calculating unit, a second calculating unit, a summing unit, a comparing unit, a power consumption calculating unit, and a selecting unit (not shown in the figure), wherein,

in the embodiment of the invention, in the compressor state matrix, the state of each compressor under any working condition changes, and a compressor state sub-matrix is correspondingly formed. Thus, the ith compressor has a rated output of A_iAnd the multi-split air conditioning system comprises L compressors, and the quantity B of the state sub-matrixes of the compressors which are formed in total is as follows:

Preferably, the adjusting module comprises: a threshold storage unit, a judgment unit, and an adjustment unit (not shown in the figure), wherein,

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention also encompasses these modifications and variations.

Claims

1. A method of controlling auxiliary electric heating in a multi-split air conditioning system, the method comprising:

2. The method of claim 1, further comprising:

acquiring running time information of each compressor;

according to the adjustment of rated power consumption, reselecting the compressor, the running frequency of the compressor and the indoor unit containing auxiliary electric heating, adding the sum of the rated heating capacity of the selected compressor and the sum of the rated auxiliary electric heating capacity of the indoor unit containing auxiliary electric heating, enabling the sum obtained by adding to be not less than the sum of the rated heating demand of the selected indoor unit containing auxiliary electric heating, and enabling the sum of the power consumption of the selected compressor and the indoor unit containing auxiliary electric heating to be minimum.

3. The method of claim 2, wherein the runtime condition comprises: one or any combination of a cumulative compressor run time condition, a compressor run time continuous condition, and a run time difference between the compressor run time continuous and a shortest run time continuous within the system.

4. The method of claim 3, wherein the cumulative run time conditions for the compressor comprise: a first run time sub-condition threshold to a fourth run time sub-condition threshold; the adjusting the rated power consumption of the compressor according to the preset adjustment amount corresponding to the running time condition comprises the following steps:

5. The method of any one of claims 1 to 4, wherein the adding the sum of the rated heating amounts of the selected compressors and the sum of the rated auxiliary electric heating amounts of the indoor unit including auxiliary electric heating such that the sum obtained by the adding is not less than the sum of the rated heating demand amounts of the selected indoor unit including auxiliary electric heating and the sum of the power consumption amounts of the selected compressors and the indoor unit including auxiliary electric heating is minimized comprises:

6. The method according to any one of claims 1 to 4, wherein the function formula for minimizing the sum of the added sums to be not less than the sum of the rated heating demands of the selected indoor unit including auxiliary electric heating and the sum of the power consumptions of the selected compressor and the indoor unit including auxiliary electric heating is calculated as:

in the formula,

b＇_ithe rated heating capacity of the ith compressor;

x_ijthe j operation state of the ith compressor;

z′_irated power consumption of the ith compressor;

wherein,

x_ije {0,1} and

and, x_i∈{0,1}。

7. The method according to any one of claims 1 to 4,

。

8. the method of claim 7, wherein the matrix equation that minimizes the sum of the summed sums to be not less than the sum of the rated heating demands of the selected indoor unit containing auxiliary electric heating and the sum of the power consumptions of the selected compressor and the indoor unit containing auxiliary electric heating is calculated as:

wherein,

9. An apparatus for controlling auxiliary electric heating, the apparatus comprising: a first parameter obtaining module, a second parameter obtaining module and a selecting module, wherein,

10. The apparatus of claim 9, further comprising: a third parameter obtaining module and an adjusting module, wherein,

11. The apparatus according to claim 9 or 10, wherein the selecting module comprises: a first parameter matrix obtaining unit, a second parameter matrix obtaining unit, a first splitting unit, a second splitting unit, a first calculating unit, a second calculating unit, a summing unit, a comparing unit, a power consumption calculating unit and a selecting unit,

12. The apparatus of claim 9 or 10, wherein the adjustment module comprises: a threshold value storage unit, a judgment unit and an adjustment unit, wherein,