[0034] The following describes the embodiments of the present invention in detail, but the present invention can be implemented in a variety of different ways defined and covered by the claims.
[0035] The present invention adopts a multi-objective variable (including return air temperature, water temperature difference, supply air temperature, etc.) segmented optimization strategy control method to adjust the opening of the water valve in a PID control mode, so that the combined air conditioner equipment is in operation. It is more energy-efficient, more comfortable, safer and more reliable.
[0036] The inventor’s long-term observation of the air-conditioning unit found that in the actual operation process, the return air temperature setting value changes simultaneously with the change of the indoor comfort index PMV parameter index. According to the indoor comfort index PMV and the return air temperature setting value T Return wind S The functional relationship between, select a reasonable T Return wind S , With a reasonable T Return wind S As the unit control target, it is an important guarantee for the indoor environment comfort to be satisfied.
[0037] figure 1 It is the control logic diagram of the control method of the present invention, where SP is the PID loop set value, which represents the control target; PV is the process variable of the PID, which represents the control variable. It should be noted, figure 1 All the symbols in the with subscript s indicate the set value.
[0038] As the first aspect of the present invention, please refer to figure 1 The present invention provides an air conditioner control method, including: obtaining the corresponding relationship between the return air temperature setting value and the indoor comfort index; and determining the corresponding relationship to the current indoor comfort index according to the current indoor comfort index and the corresponding relationship The current return air temperature setting value; if the current return air temperature fluctuates within the range of the current return air temperature setting value +/- the first switching deviation, adjust the opening of the water valve according to the temperature difference between the supply and return water , Otherwise, adjust the opening of the water valve according to the return air temperature. Among them, +/- means "+ and/or -".
[0039] Specifically, first, the corresponding relationship indicates a mapping relationship between the obtained return air temperature setting value and the indoor comfort index. On this basis, if the current real-time indoor comfort index is known, then the corresponding current return air temperature setting value can be obtained according to this correspondence.
[0040] Then, determine the deviation between the currently measured return air temperature and the current return air temperature set value, that is, determine whether the current return air temperature fluctuates up and down within the first switching deviation centered on the current return air temperature set value , Which is the interval corresponding to the current return air temperature setting value +/- deviation.
[0041] In fact, the method of the present invention includes the following two control modes: (1) Water temperature difference control mode, the control variable is the water temperature difference (that is, the temperature difference between supply and return), and the control target is the set value of the water temperature difference: if the current return When the air temperature fluctuates within the range of the current return air temperature setting value +/- the first switching deviation, the opening of the water valve is adjusted according to the temperature difference between the supply and return water. (2) Return air temperature control mode, the control variable is the return air temperature, and the control target is the return air temperature setting value: the current return air temperature is up and down outside the first switching deviation centered on the current return air temperature setting value When fluctuating, the opening of the water valve is adjusted according to the return air temperature.
[0042] Therefore, the present invention realizes multi-target variable segmented optimization control, and can switch between the water temperature difference control mode and the return air temperature control mode according to the change of the return air temperature.
[0043] The present invention is based on the basic heat exchange characteristics of the heat exchanger of air conditioning equipment with large temperature difference, small flow rate, small temperature difference and large flow rate. At the same time, in a certain area that meets the conditions, the conversion adopts a reasonable water temperature difference (for example, according to the system and surface cooling The technical parameters of the device are determined) to control the water valve, which can reduce the opening of the water valve to achieve energy saving effect. At the same time, it can also avoid the problems of frost at the air supply outlet and excessive adjustment of the water valve.
[0044] Since when the water temperature difference control mode is adopted, the heat exchange efficiency of the heat exchanger will be fully utilized. At this time, the efficiency of the heat exchanger is higher than that in the return air temperature control mode. Therefore, when the same cooling capacity is required to maintain the indoor load, the water temperature difference control mode requires relatively less water flow than the return air temperature control mode, so that the water temperature difference control mode can reduce the control state of the water valve to achieve energy saving purposes. ; At the same time, establish the corresponding functional relationship between the set value of the return air temperature of the equipment and the indoor indoor comfort index PMV (Predicted Mean Vote), which can achieve the purpose of improving the indoor high-comfort environment demand.
[0045] Preferably, the corresponding relationship is determined by fitting between the return air temperature setting value and the indoor comfort index. For example, this kind of fitting can be performed using various numerical calculation methods.
[0046] Preferably, in an embodiment, the corresponding relationship is:
[0047] Under refrigeration conditions:
[0048] When PMV Return wind S =28,
[0049] When -0.5≤PMV≤1, T Return wind S =-6*PMV+25,
[0050] When PMV>1, T Return wind S =19;
[0051] And/or, under heating conditions:
[0052] When PMV>0.5, T Return wind S =22,
[0053] When -1≤PMV≤0.5, T Return wind S =-6*PMV+25,
[0054] When PMV Return wind S =31;
[0055] Among them, PMV is the current indoor comfort index; T Return wind S Set value for current return air temperature.
[0056] Obviously, the above-mentioned relational expression is only a preferred corresponding relation, and other corresponding relational expressions can be obtained according to the reasonable selection and determination of the control target setting value parameters (determined according to the technical parameters of the system and the surface cooler). For example, under different ranges of PMV values, different formulas can be used to obtain T Return wind S Further, the PMV value can be divided into more segments, and each segment is calculated by the corresponding formula. Return wind S Value. After all these segments PMV, the corresponding T in each segment is given Return wind S The modes can be regarded as equivalent or modified alternative modes of the corresponding relationship in the present invention.
[0057] Preferably, in an embodiment, the first handover deviation is determined according to the following formula:
[0058] Under refrigeration conditions:
[0059] When T Air supply26℃, T Switching deviation =0.5,
[0060] When T Air supply When ≤26℃, T Switching deviation =1-(T Air supply -16)/20;
[0061] And/or, under heating conditions:
[0062] When T Air supply ≥35℃, T Switching deviation =1-(40-T Air supply )/15,
[0063] When T Air supply <35℃, T Switching deviation =0.5;
[0064] Where T Air supply The supply air temperature of the air conditioner; T Switching deviation Is the size of the first switching deviation.
[0065] Obviously, the above relational expression is only a preferred way to determine the first switching deviation, and other corresponding relational expressions can be obtained according to the reasonable selection and determination of the control target setting value parameter (determined according to the technical parameters of the system and the surface cooler). For example, different T Air supply Under the range of, use different formulas to get T Switching bias difference The value of; further, T Air supply Divide into more segments, and calculate T through the corresponding formula for each segment Switching deviation Value. All this to T Air supply After segmenting, give the corresponding T in each segment Switching deviation The methods can be regarded as equivalent or modified alternative methods for determining the first switching deviation in the present invention.
[0066] Preferably, the control method further includes: when the air supply temperature of the air conditioner exceeds the second switching deviation of the air supply upper limit and/or the air supply lower limit, adjusting the opening of the water valve according to the air supply temperature. The method of the present invention also includes a supply air temperature control mode, which uses the supply air temperature as a control variable.
[0067] That is to say, while the water temperature difference control mode and the return air temperature control mode are running, the supply air temperature control module is also run through the entire control process of the unit equipment, which switches according to the upper and lower protection modes of the supply air temperature value to Play the purpose of protection, reliable and safe operation.
[0068] Preferably, the opening degree of the water valve is adjusted according to the temperature difference between the supply and return water and/or the opening degree of the water valve is adjusted according to the return air temperature using a PID algorithm. In particular, when PID is adjusted, it is not the maximum opening when it first deviates from the set range.
[0069] Please refer to figure 1 During the operation of the air-conditioning unit, the corresponding function relationship between the indoor comfort index PMV and the return air temperature setting value can be calculated to obtain the return air temperature setting value that satisfies the indoor high comfort, and then the multiplier in the present invention is adopted. The target variable segmentation optimization control strategy, through the PID control method to adjust the opening of the water valve. Combine below figure 1 The control logic of the method in the present invention is schematically described in detail.
[0070] (1) Through indoor comfort index PMV and return air temperature setting value T Return wind S The functional relationship between the air conditioning unit corresponds to the indoor room to meet the comfort of the return air temperature set value T Return wind S.
[0071] (2) Return air temperature control mode:
[0072] When T Return air ≥T Return air S+T Switching deviation (Refrigeration) or T Return air ≤T Return wind S -T Switching deviation (Heating), the air-conditioning unit uses T Return wind S As the control target, the return air temperature is used as the control variable, and the opening degree of the water valve is adjusted by PID control; among them, T Switching deviation It is obtained by reasonable calculation and selection of the supply air temperature value according to the above method.
[0073] (3) Water temperature difference control mode:
[0074] When the return air temperature reaches the set temperature range, for example, under cooling conditions,
[0075] When T Return wind S -T Switching deviation ≤T Return air ≤T Return wind S +T Switching deviation Time,
[0076] The unit switches the control target to supply the return water temperature difference setting value △T Supply and return water temperature difference S (This parameter can be set: such as 10℃-5℃, determined according to the characteristics of the system) As the control target, the opening of the water valve is adjusted by PID control to achieve the △T Supply and return water temperature difference S Stable control of variables, make full use and play to the heat exchange performance of the combined air conditioner; when T Return air Beyond T Return wind S +/-T Switching deviation When it is outside the range, it returns to the return air temperature control mode.
[0077] (4) Supply air temperature control mode:
[0078] During the entire control process, in cooling mode
[0079] When T Air supply Lower limit of air supply S -0.5 (T Lower limit of air supply S Can be set: 13℃/16℃, according to equipment system performance),
[0080] Or in heating mode
[0081] When T Air supplyT Maximum air supply S +0.5 (T Maximum air supply S Can be set: 35℃/40℃, according to equipment system performance),
[0082] Unit separately T Lower limit of air supply S (Refrigeration) or T Maximum air supply S (Heating) As the control target, the supply air temperature variable is controlled, so as to adjust the opening of the water valve in PID control mode to realize the protection of the supply air temperature and avoid the occurrence of excessively low or high air supply temperature;
[0083] When T Air supplyT S under air supply (Refrigeration) or T Air supply Air supply S (Heating), then return to the above return air temperature control mode or water temperature difference control mode.
[0084] After adopting the multi-objective variable segmented optimization control strategy of the present invention, through test data analysis, the opening degree of the water valve of the combined air-conditioning equipment can be greatly reduced compared with the original conventional control method. Among them, the reasonable selection of two technical parameter points is more critical:
[0085] One, T Switching deviation , If you choose within +/-0.5℃, the cycle switching frequency between the two modes is fast, which makes the water temperature difference control process shorter and the average water flow larger, which will cause the waste of cold and heat to achieve the ideal energy-saving effect; If it is selected outside +/-1.5℃, the return air temperature will fluctuate greatly due to the long time of entering the water temperature difference control process, so the air supply temperature and T Switching deviation The functional relationship between, must choose a reasonable T Switching deviation Switch between the return air temperature control mode and the supply and return water temperature difference working mode.
[0086] Second, the set value of temperature difference between supply and return water △T Supply and return water temperature difference S Reasonable selection (parameters can be set to 10℃-5℃), which is mainly related to the characteristics of the heat exchanger of the unit and the system design (for example, when 5℃ is selected for a conventional system, the heat exchange efficiency is the highest. If an elliptical tube or more For systems such as piping, it is more reasonable to select 10°C). On the premise of reasonable water temperature difference setting value, after entering the supply and return water temperature difference control mode, the opening of the water valve will be automatically adjusted to stabilize the supply and return water temperature difference within a small range of the target value, giving full play to the heat exchange Thermal performance, thereby reducing the opening of the water valve (ie water flow), achieving the purpose of energy saving in the water system.
[0087] Further, the supply air temperature control mode in the present invention can protect the operation of the equipment to prevent the supply air temperature from being too high or too low. Among them, the parameters of the supply air temperature upper limit protection point and lower limit protection point are reasonably selected It is very important to set the parameters and return difference. Such as: when T in cooling mode Air supply Lower limit of air supply S -0.5 (T give away Lower wind limit S Can be set: 13℃-16℃, determined by the system), when the heating mode is T Air supplyT Maximum air supply S +0.5 (T Maximum air supply S Can be set: 35℃-40℃, determined by the system). If the upper and lower protection points are selected too low or too high, it will cause frequent switching of the air supply mode or no anti-frosting effect.
[0088] In particular, the PID control in the present invention will be exemplarily described below.
[0089] A. When the current return air temperature fluctuates within the range of the current return air temperature setting value +/- the first switching deviation, PID adjusts the opening of the water valve according to the temperature difference between the supply and return water. PID adjustment at this time: SP is the PID loop set value, which represents the control target, at this time SP=the set value of the temperature difference between the supply and return water; PV is the process variable of the PID; at this time PV=the sampling value of the temperature difference between the supply and return water; output Adjust the output of the water valve according to the PID control mode.
[0090] B. If the current return air temperature fluctuates outside the range of the current return air temperature setting value +/- the first switching deviation, adjust the opening of the water valve according to the return air temperature. PID adjustment at this time: SP is the PID loop set value, which represents the control target, at this time SP=return air temperature set value; PV is the process variable of PID; at this time PV=return air temperature sampling value; output is in accordance with PID Control mode for water valve output adjustment
[0091] As a second aspect of the present invention, an air conditioning unit is provided, which uses the above-mentioned control method.
[0092] Please refer to figure 2 , A comfort detector 2 is installed in the room 1, a supply air temperature sensor 9 is installed at the air supply end of the air duct 8, a return air temperature sensor 10 is installed at the input end of the return air 7 of the air duct 8, and a water supply pipe is installed There is a water supply temperature sensor 11, and a return water temperature sensor 12 is installed on the return water pipe. The refrigerated circulating water flows through the heat exchanger 3 in the combined air conditioner, and the cooling (heating) ) The amount is converted into the energy required by the indoor load to form the air conditioning system structure of the combined air conditioner.
[0093] Under the system structure of the unit, the controller 5 collects the supply air temperature T in real time Air supply , Return air temperature T Return air , Water supply temperature T Water supply , Return water temperature T Backwater Temperature difference between supply and return water △T Supply and return water After the arithmetic processing of the controller 5, according to the control method of the present invention, the opening degree of the water valve 6 is adjusted by the PID control method, and the blower 4 is controlled by the direct start method.
[0094] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc., made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
