COMPUTER DECOUPLE CONTROL OF TEMPERATURE AND HUMIDITY IN PREPROCESSING CHAMBER OF AIR-CONDITIONING TEST EQUIPMENT

This paper deals with the application of decouple Control theory to temperature and humidi-ty control in air-conditioning system. The decouple control algorithm for bivariable systems isderived applicablly for air-conditioning system. The algorithm is used to design a temperatureand humidity computer control system for the preprocessing chamber of air-conditioning testequipment. The results of the real-time control experiments indicate that the decouple controlalgorithm is feasible, the control quality is improved and high control precision is achieved.

Design of greenhouse temperature and humidity wireless control system based on CC3200

Referring to the shortages that the process of traditional greenhouse measurement by using thermometer and hygrometer is complex,the measurement result is not accurate,and the control system operation is cumbersome,a greenhouse temperature and humidity(TH)control system based on CC3200 is designed.The system uses FPGA as the main controller,sends the TH signals to the wireless module CC3200 by controlling DHT22.The proposed system realizes the remote transmission of data and the automatic control of system.

Visco-elastic-plastic model of deep underground rock affected by temperature and humidity

As the depth of exploitation increases,studies on constitutive models of rock affected by temperature and humidity become very important.Based on the Nishihara model,a visco-elastic-plastic rock model was established by using the coefficients of thermal and humidity expansion,thermal viscosity attenuation,humid viscosity attenuation and acceleration rheology components.We used the definition of a controlled heat circle to explain the model.The results show that the behavior of rock,affected by temperature and humidity,is stable as a function of time when the stress is lower than the first yield stress σS1;the creep rate will increase due to the effect of temperature and humidity when the stress is greater than or equal to σS1;the creep rate will accelerate at an increasing rate when the stress is greater than or equal to the second yield stress σS2,which results in a failure of the roadway.The model derived in this study can completely describe visco-elastic-plastic characteristics and reflects the three stages of rock creep.

Temperature and Humidity Control in Greenhouses in Desert Areas

Water consumption can be reduced by using a greenhouse for agriculture in desert areas. We analyzed the effect of control of ventilation, sprinkler water, and solar radiation?shielding on changes of temperature and humidity in a greenhouse under various desert area conditions. We calculated the changes in temperature and humidity in a greenhouse for a whole day in four seasons, and the calculation results of water consumption with and without a greenhouse were compared. When ventilation, shielding, and sprinkler water were controlled under suitable conditions to grow orchids in a desert area, water consumption in July was only 7% of that without a greenhouse.

Development of Temperature-Humidity Independent Control Air-Conditioning Unit for Residential Buildings

Cooling panels are increasingly used in domestic residential buildings.To provide medium temperature cold water for the cooling panel,and dehumidify the indoor air simultaneously,a new kind of temperature-humidity independent control air-conditioning unit was developed for single residential house by utilizing multi-variable technology.First,the supply air temperature was studied to determine the proper supply air flow rate for the humidity control.Then,the energy consumption of different temperature-humidity independent control systems was studied.The analysis indicates that unity evaporating temperature can be used to handle the moisture load and sensible heat load in two evaporators.So the unit scheme was put forward.Two evaporators were used to produce medium temperature water and dry air separately,and electric expansion valves were used to control the refrigerant distribution between the two evaporators.Then,experimental work was carried out to investigate the influence of compressor frequency,refrigerant distribution on the dehumidification capacity,energy efficiency and refrigeration capacity.In the end,the paper concludes that both compressor frequency and refrigerant distribution can control the dehumidification capacity,but the former influences the EER more than the latter,while the latter influences the refrigeration capacity more than the former.We can find a proper running point at certain sensible and latent cooling load by adjusting both compressor frequency and electric expansion valve.The energy consumption of this kind of unit was estimated and compared with present room air conditioners,which shows that it can save about 41% cooling energy consumption.

Reliability Evaluation of Wind Power Converter Under Fault-tolerant Control Scheme with Quantification of Temperature and Humidity Effects

Wind power converter(WPC)is a key part of a wind power unit which delivers electric energy to power grid.Because of a large number of semiconductors,WPC has a high failure rate.This paper proposes a method to accurately evaluate the reliability of WPC,which is crucial for the design and maintenance of wind turbines.Firstly,the index of effective temperature(ET)is presented to quantify the effects of temperature and humidity on the semiconductor operation.A novel method is proposed to evaluate the lifetime and calculate the aging failure rates of the semiconductors considering the fluctuations of ET.Secondly,the failure mode and effect analysis(FMEA)of WPC is investigated based on the topology and control scheme.The conventional two-state reliability model of the WPC is extended to the multi-state reliability model where the partial working state under the fault-tolerant control scheme is allowed.Finally,a reliability evaluation framework is established to calculate the parameters of the WPC reliability model considering the variable failure rates and repair activities of semiconductors.Case studies are designed to verfify the proposed method using a practical wind turbine.

Room temperature and humidity decoupling control of common variable air volume air-conditioning system based on bilinear characteristics

Variable air volume(VAV)air-conditioning(AC)systems are widely employed to achieve a comfortable room thermal and humid environment depending on its better regulation performance and energy efficiency.In the single coil VAV AC system,conventional proportional-integral(PI)control algorithm is usually adopted to track the set-points of the room temperature and humidity by regulating the supply air flow rate and the chilled water flow rate,respectively.However,the control performance is usually not good due to the high coupling of the heat and mass transfer in the air-handling unit(AHU).A model-based control method is developed to realize the decoupling control of the room temperature and humidity according to the bilinear characteristics of the temperature and humidity variation.In this control method,a bilinear room temperature controller is used to track the room temperature set-point based on the real-time cooling load,while a room humidity controller is used to track the room humidity set-point depending on the real-time humidity load.The control performance was validated in a simulated VAV AC system.The test results show that comparing with the conventional PI control,the room temperature and humidity are controlled much more robustly and accurately by using the proposed model-based control method.

Thermodynamic performance assessment of vacuum membrane-based dehumidification and air carrying energy radiant air-conditioning system(VMD-ACERS)

Temperature and humidity independent control(THIC)air-conditioning system is a promising technology.In this work,a novel temperature and humidity independent control(THIC)system is proposed,namely VMD-ACERS,which integrates vacuum membrane-based dehumidification and air carrying energy radiant air-conditioning system.This work establishes a novel coefficient of performance(COP)model of VMD-ACERS.The main parameters affecting the COP of conventional fan coil unit cooling system(FCUCS)and VMD-ACERS are investigated.The performance of FCUCS and VMD-ACERS are compared,and the energy-saving potential of VMD-ACERS is proved.Results indicate that,for FCUCS,the importance ranking of parameters is basically stable.However,for VMD-ACERS,the importance ranking will be affected by FCU and refrigerant.The most important parameters of VMD-ACERS are condensation temperature and permeate side pressure.On the contrary,superheating,subcooling are relatively less important parameters.For VMD-ACERS,it is not necessary to pursue the membrane with very high selectivity,because the selectivity of membrane would also be a less important parameter when it reaches 500.The COP of VMD-ACERS is higher than that of FCUCS when the permeate side pressure is higher than 8 k Pa.The VMD-ACERS solves two technical problems about power-saving and thermal comfort of conventional THIC,and can extend the application of THIC air-conditioning system.

Optimization of hot-air microwave combined drying control system based on air outlet temperature and humidity monitoring

Microwave drying is one of the most important drying methods in agriculture.The online measurement and control of material dried,as a challenging research issue,is helping to improve the drying quality of the final product and the energy utilization efficiency of microwave dryers.In order to realize the online measurement of temperature in microwave drying,a detection strategy was based on the temperature and humidity monitoring at the air outlet of coupling hot air and microwave drying method.LabVIEW programming software was employed to collect the temperature and humidity signal value at the outlet of the dryer to estimate the drying degree of the material.According to the amount of moisture removal in real-time,the microwave input power was adjusted gradually in the microwave drying process.Taking potato as material dried,the microwave power of microwave and hot air coupling drying is monitored to realize the real-time regulation.The results showed that the total color difference value of the product of 3.09,the rehydration ratio of 2.92,the unit energy consumption of 17419.35 kJ/kg,and the drying rate of 0.442 g/s were obtained.The minimum comprehensive weighted score of the product was 26.36.Compared with the orthogonal experiment,the optimal drying process was obtained as the total color difference value of the product of 2.84,the rehydration ratio of 3.01,the unit energy consumption of 17419.35 kJ/kg,and the drying rate of 0.397 g/s.The minimum comprehensive weighted score of the product was 20.67,and the difference was not significant.The control strategy not only solves the non-uniform phenomenon of drying,and makes the microwave drying real-time and continuous,but also improves the drying efficiency and quality.

杭州国家版本馆恒温恒湿空调系统设计

介绍了恒温恒湿库房空调系统的设计,提出了可在库房建成初期、运行稳定期、战时等灵活切换的3种运行模式,分析了其各自的处理过程与节能性;给出了平、战时空调系统选择方案,提出了平时回收空气源热泵机组和冷水机组的冷凝热作为再热热源,战时利用新风预冷实现温湿度独立控制的方法;利用CFD模拟对室内气流组织进行了优化设计;提出了采用含湿量控制代替定露点法进行湿度控制和风机变频等控制策略。通过调试与运行,证明了各项设计措施在项目中应用的有效性。

基于LSTM神经网络的烟丝水分恒定控制系统设计

在烟丝加工过程中,水分分布受到温度、湿度多个因素的影响,控制系统无法准确反映整体水分情况;为全面提高加工型香烟的质量水平,设计基于LSTM神经网络的烟丝水分恒定控制系统;部署Profibus控制总线,并在线路体系中连接水分检测仪与水分恒定器,完成烟丝水分恒定控制系统的硬件设计;在系统软件设计方面,构建LSTM神经网络单元,根据烟叶吸湿能力分析条件,求解具体的水分分布模型,实现基于LSTM神经网络的烟丝水分模型建模;分别计算烟叶出口湿度与出口温度,并联合传递函数逼近参量与恒定时滞参数,完成对控制参数的整定处理,再联合相关应用部件,实现基于LSTM神经网络的烟丝水分恒定控制系统设计;实验结果表明,LSTM神经网络模型作用下,生丝含水量被稳定控制在13%~18%数值之间,不会因水分过量问题而导致香烟质量水平无法达到实际加工标准。

换热器面积对双蒸发温度空调系统性能影响的模拟研究

建立了双蒸发温度空调系统仿真模型来研究改变换热器面积对系统性能的影响。搭建了双蒸发温度空调系统实验台,在实验工况下改变压缩机频率(30~120 Hz)和送风量(400~1 000 m^(3)/h),得到空调机组总制冷量Q_(c)、总显热制冷量Q_(s)和显热比SHR,验证了所建模型精度。在模型中改变换热器面积(48盘管、60盘管、72盘管)进行系统运行调节范围的研究。结果表明:随着换热器面积的增加,系统Q_(c)、Q_(s)和SHR的调节范围在整体扩大,最大增幅分别为5.0%、13.8%、11.8%。当送风量为1 000 m^(3)/h,压缩机频率为30 Hz,换热器面积从48盘管增至60盘管、72盘管时,Q_(s)的增幅分别为9.8%和13.8%,表明换热器面积增至60盘管时Q_(s)增长效果显著,再增加换热器面积,Q_(s)虽有所增大但增幅放缓。最后提出一种以所需制冷量为目标,依据环境温湿度调节范围设计换热器面积的方法。

基于温湿度控制设计地下抗裂防渗漏混凝土的应用研究

文中基于温湿度控制思路,通过大掺量粉煤灰、多级配低空隙率骨料、分段补偿收缩和温湿度监测调控等成套技术设计抗裂防渗漏混凝土,以缓解或彻底消除地下结构开裂渗漏。

基于大数据的超声波温控在线检测系统设计与实现

设计了一种基于大数据的在线超声波质量检测系统,包括滑座,滑座上设有调节机构、驱动机构、检测机构、转动件、限位机构,通过固定板转动检测仪的方式对结构板两侧进行自动检测,检测结果直接通过控制系统显示在计算机上,结合检测结果大数据分析与比对,改变了人工检测时需要手持检测仪不断变换位置,较为消耗体力,使检测效率不高的问题,可以实现时时调整检测位置和检测频率,检测方便,效率高,能够实现长距离海底管道的超声波无损检测。检测效率可以达到传统检测仪器的3倍以上,还可以准确定位缺欠位置,为故障诊断和排除提供了有力依据。系统可以利用计算机网络单元进行检测数据采集和分析,为长距离海底管道的检测提供技术支持和数据保障。

煤矿氧气检测高精度VCSEL驱动及温控电路设计

为解决当前常用煤矿氧气检测仪器易受交叉气体干扰且功耗大的问题,基于GD32F303RCT6微控制器和ADN8834热电冷却控制器,设计了一种软启动开关电路控制的垂直腔面发射激光器(Vertical-cavity Surface-emitting Laser,VCSEL)高精度驱动及温控电路。驱动电路中,高频正弦波信号和低频锯齿波信号叠加的二进制数据由微控制器产生,经信号发生电路、电压电流转换电路转化成VCSEL高精度驱动电流信号;温控电路中,设计基于比例积分微分(Proportional Integral Differential,PID)补偿电路和数模转换控制器(Digital to Analog Converter,DAC)目标温度控制电路实现激光器温度自动调节。测试结果表明:驱动电路的电流输出区间为0.680~1.360 mA;锯齿波频率误差小于0.5%,正弦波频率误差小于0.1%;氧气吸收峰扫描精度高达0.07 pm,对应电流扫描精度为0.12μA;温控电路的温度控制精度为±0.012℃。满足了可调谐半导体激光吸收光谱(Tunable Diode Laser Absorption Spectroscopy,TDLAS)煤矿氧气检测应用需求。

应用模糊PID自修正的电镀槽液温度控制方法

电镀槽液温度自动控制过程属于典型的混沌过程,在温度采集的过程中存在明显的非线性波动。典型的比例-积分-微分(PID)控制算法在这种混沌特性与非线性特性干扰下,存在控制精度较低、稳定性和鲁棒性较差等问题。此外,为解决非线性问题,PID算法需要循环迭代计算,存在控制时滞问题。以模糊控制为基础,提出了基于模糊PID的电镀槽液温度自动控制方法。该方法先设计温度数据采集结构,并将移动平均滤波、温度修正算法引入到采用的数据采集结构中,完成电镀槽液的实时温度数据采集。然后将采集到的温度数据作为构建的模糊PID控制器的输入。利用模糊控制规则引入修正因子,实现电镀槽液温度的自动控制。考虑到电镀槽液的时滞特性,在控制器中加入粗糙预估参考模型,对该特性加以抑制,提升控制性能。最后应用实验证明了所提方法的先进性。实验结果表明:所提方法具有较高的控制精度和效率,能够有效降低超调量和波动,应用效果较好。

基于控温控湿的沙棘红外联合热风干燥均匀性与工艺

新鲜沙棘含水率高且易腐烂变质,干燥是延长货架期的重要方式之一。针对现有沙棘热风干燥周期长、品质差、能耗高等问题,该研究基于控温控湿设计了一种红外联合热风干燥装置,并对装置的气流分配室结构进行了优化,设计了一种圆柱形扰流板和方形挡风板,利用数值模拟软件COMSOL对干燥装置中速度场、温度场和湿度场进行了模拟,结果表明通过增加半圆柱扰流板能够改变干燥层间气流量,解决干燥不均匀性问题;借助增设扰流板能够提高气流速度,利用自由流区域高温低湿干燥介质的干燥能力,防止干燥层内不同区域出现干燥不均匀的现象。优化后的干燥室结构将5个干燥层间的最大速度偏差比显著降低。以沙棘为研究对象对干燥工艺进行了试验研究。结果表明,不同干燥温度对沙棘控温控湿红外联合热风干燥时间有显著影响,干燥水分比随干燥时间的增加呈现指数下降趋势。基于层次分析法得到各干燥特性和干燥品质权重,采用综合评价方法得到不同干燥温度下75℃干燥条件综合评分最高。不同介质湿度干燥条件下,当介质湿度为10%干燥时,干燥所需能耗最低,干燥后沙棘复水比最高,具有最高的维生素C(vitamin C,Vc)保留率和总黄酮含量,综合评分最高。40%介质湿度不同持续时间下,40 min得到的沙棘亮度值、复水比、Vc保留率和总黄酮含量最高,综合评分最高。该研究明确了控温控湿沙棘红外联合热风干燥最优工艺,对提升沙棘产地初加工机械化水平,促进沙棘产业健康持续发展具有重要意义。

基于主元分析的温室物联网空气温湿度传感器故障诊断

针对温室物联网测控系统中空气温湿度传感器受恶劣环境影响易发生故障的问题,研究温室物联网测控系统中空气温湿度传感器的故障诊断,保障温室物联网测控系统整体工作的稳定可靠性,提出一种基于主元分析的空气温湿度传感器故障诊断方法。首先对空气温湿度传感器数据进行主元分析,通过监控平方预测误差统计量的变化实现传感器的故障检测;再针对检测出的空气温湿度传感器故障数据,利用加权后的平方预测误差统计量来计算传感器的累积贡献率,并将其作为传感器故障识别的指标,识别出现故障的空气温湿度传感器。利用空气温湿度传感器数据在不同故障条件下进行传感器故障诊断方法验证,验证结果表明:所提方法可用于温室物联网测控系统中空气温湿度传感器偏差故障和漂移故障的检测,偏差故障的检测效果要好于漂移故障,偏差故障综合检测率为100%,漂移故障综合检测率为51.25%;同时所提方法能够正确识别出故障传感器,有效提高温室物联网测控系统中空气温湿度传感器故障诊断结果的准确性。

基于窄带物联网的茶叶灭虫控制系统研究

为克服当前物联网在丘陵地区农业生产过程中存在通信距离短、消耗功率大、终端数量易饱和等问题,以茶叶虫害防治为研究对象,将窄带物联网技术与农业生产相结合,实时精准监测土壤温湿度,并根据土壤温湿度数据变化远程控制茶叶灭虫电磁阀启闭状态,设计了智能茶叶灭虫控制系统,并优化了超级电容太阳能电源管理、无线传感网络监测、远程监测控制等核心技术及关键模块。试验结果表明:系统运行稳定,能通过窄带物联网技术实时监测、传输土壤温湿度信息,终端可实时远程控制茶叶灭虫电磁阀,实时启闭茶叶灭虫系统,达到了实时精准监测和远程控制的目的。研究弥补了当前物联网在农业生产中应用的不足,提高了太阳能电源使用效率,延长了蓄电池使用寿命,可为我国智慧农业发展提供参考。

畜牧养殖智能饮水控温系统设计与试验

为提升草原放牧牛羊福利化养殖装置性能,开发一种基于多传感器原位数据检测与模糊PID控制相结合的畜牧养殖智能饮水控温系统。该系统主要由数据采集模块、注水加热模块、温度控制模块以及远程数据监测模块组成。数据采集模块是采用多种传感器对饮水装置中水温、水质、水量等信息实时采集;注水加热模块采用底部注水加热的形式,便于水温自下而上发生层流流动,使水温分布更均匀;温度控制模块采用基于闭环负反馈模糊PID控制算法,自整定PID系数,实现水温精准控制;远程数据监测模块是针对用户设计,便于用户实时观察饮水装置的工作情况。对系统开展模糊PID控温测试以及水温温场均匀性试验验证与仿真分析,试验结果表明:模糊PID控温效果与常规PID控温相比,模糊PID控温曲线更光滑,加热响应速度更快,当预设水温目标温度为23℃,入水水温分别为7℃、9℃、11℃、13℃、15℃时,实际加热温度与目标温度的波动幅度最大仅为0.3℃;对不同测温点加热,得同一水平面不同测温点最大温差为0.3℃,水槽不同截面水温温差小于0.2℃,装置测温点水温能精准控制在23℃±0.5℃。畜牧养殖智能饮水控温系统的水温温度场均匀性良好,能够为福利化养殖提供装备支持。