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.

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.

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.

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.

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.

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.

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.

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。

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SO-BP神经网络的温室环境预测模型研究

由于温室环境中温湿度的调控过程存在滞后响应特性,预测温室环境变化趋势是构建温室精准控制系统中不可或缺的一部分。针对传统神经网络算法在温室预测方面精度不足等问题,提出一种基于蛇优化算法(snake optimizer,SO)优化BP神经网络的温室环境预测方法。试验结果表明,该方法预测15 min内温度的决定系数R^(2)为0.9564,比BP模型、HHO-BP模型分别提高14.87%、2.19%,平均绝对误差MAE、平均绝对百分比误差MAPE、均方根误差RMSE值分别为0.4813、2.2378、0.6729;预测15 min内湿度的R^(2)为0.9821,比BP模型、HHO-BP模型分别提高13.12%、2.37%,预测指标MAE、MAPE、RMSE值分别为1.7090、2.5842、2.2838。该模型的预测结果较理想,可用于温室温湿度预测。

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。

基于规模化保育猪舍的全新风通风负荷计算模型及测试分析

猪舍的全新风通风不仅能提升猪舍环境质量,还能降低规模化养殖中的交叉感染问题。以保育猪为研究对象,建立了全新风通风负荷计算模型,应用该模型与传统逐时逐项冷负荷方法计算的负荷结果差异小于5%,可应用于工程简化计算。在该模型基础上,提出耦合不同室外气象参数下的猪舍环控参数动态调控方法。通过试验验证,该调控策略下舍内温度测试值与理论值平均相对误差为3.4%,且能够满足夏季猪舍温度、风速控制值及均匀性要求。在冬季运行工况下应用该调控方法,每栏仅需150 m^(3)/h风量即可满足舍内空气质量要求;理论送风参数下,测得舍内空气平均温度约26℃,日平均温差5℃,CO_(2)、NH_(3)、PM_(2.5)等污染物浓度均远低于国家标准指标。该负荷计算模型及动态调控方法可为规模化保育猪舍的热环境与卫生环境研究提供参考。

黄茶自动化闷黄装备设计与温湿度控制方法研究

闷黄是黄茶加工中的特有工艺,目前黄茶加工中缺乏专用的连续化、自动化闷黄加工装备。为此,本文设计一种用于黄茶闷黄的专用装备。根据连续化加工需求,设计了闷黄装备的机械结构,核算了装备所需的加热功率和蒸汽流量,并完成了相关部件的选型和样机构建,提出了一种基于区间二型模糊理论的温湿度控制算法。温湿度控制系统试验结果表明,在不同试验条件下,区间二型模糊控制算法能够精准控制温湿度参数,对比一型模糊控制算法,对扰动的抑制能力更强,控制误差更小。生产试验结果表明,温度和相对湿度的均方根误差最大值分别为0.439 1℃和1.226 2%,产品的感官评审结果表明,采用该装备加工的产品符合皖西黄茶的品质要求。

纺纱空调系统运行仿真及机器学习辅助调控

针对纺纱车间采用传统的PID控制车间温湿度不稳定问题,采用机器学习的BP神经网络对后台历史数据进行监督学习,并建立空调设备自控参数的专家库。当PID调控产生温湿度较大波动时采用信息库建立好的空调控制参数直接介入辅助控制。基于热量平衡、湿量平衡以及风量平衡开发了纺纱空调仿真系统,并分析了风机、水泵、二回风窗、新风窗对于车间温湿度控制的影响。为验证辅助调控的效果,将BP神经网络预测的空调控制参数介入车间温湿度控制,并与传统PID控制车间的温湿度进行了对比。结果表明:采用BP神经网络辅助调控空调系统的参数,车间温湿度稳定性优于传统PID控制。认为:机器学习辅助调控纺纱空调系统可达到稳定控制温湿度的目的。

玉米烘干自动监控系统设计

谷物干燥监控系统可以实时监测谷物烘干过程中的温度、湿度等关键参数,保证谷物在烘干过程中达到理想的水分含量,从而保证产品质量和食品安全。为提高玉米烘干效率,对玉米烘干过程进行监控。该文提出一种基于DCS的玉米烘干自动监控系统的设计,对输入模块、监控模块和输出模块进行设计,建立实时监测和报警机制,同时结合先进的自动化控制技术,能够有效提高烘干效率,降低能源消耗,提升生产质量,具有重要的应用价值和推广前景。

基于PLC控制的流体温湿度自动控制系统研究

针对某性能分析试验台架传统的手动操作进行了自动化改造,阐述了改造的整体思路,给出了硬件结构的系统结构图及软件设计流程;基于PLC控制与主机通信自动调整试验参数与自动采集存储试验数据;引入云端服务器,将数据实时传入云端,实现对试验台架的远程控制及远程数据读取保存。结果表明,经改造后的性能分析试验台架在自动模式下实现了全自动调节温湿度参数直至试验达到稳定状态,且在手动模式下,可调节本地与远程两端的试验参数,极大地提高了系统的稳定性。在两种模式下,该系统可大大降低劳动强度,减少工作量,缩短工作时间,提高工作效率。

绣片柜模糊PID温湿度控制系统

为解决绣片储存在高温、高湿环境中出现的绣线变色、绣布破损问题,设计了一个绣片柜模糊PID(Proportional Integral Derivative)温湿度控制系统。采用单片机STM32、风扇等元件共同构建硬件控制系统。通过将模糊PID控制温湿度值作为输入变量,脉冲宽度调制(PWM)红外管和风扇转速作为输出变量,实现对存储环境中温湿度的控制;使用矩阵实验室软件Matlab对模糊PID控制进行仿真分析。结果表明,与传统PID控制相比,加入模糊控制后,对温湿度的超调量分别由18.75%和15.34%降低至2.51%和2.46%,并且系统不易受外界干扰,能够快速稳定运行。以上结果说明模糊PID控制满足绣片储存的温湿度环境要求。

温湿度冷链监控管理系统在医院药品质控管理中的应用

通过安装温湿度冷链监控管理系统,监测冷链药品温湿度。比较2022年9月—2023年2月医院药品库房和冰箱系统监测记录的温湿度与人工记录温湿度温度超标和预警情况,总结影响存储药品库房和冰箱温湿度超标的原因,提出相应的解决办法,大大降低了药品质量问题的风险。为相关部门进行冷链药品储存条件检查时提供了可靠的数据和图像。所以,温湿度冷链监控管理系统为冷链药品的储存条件提供了更可靠、有效、高效的保障,更有利于保障冷链药品的安全有效,逐步实现医院冷链药品/试剂在冷链环节全程的信息化、智能化监控管理提供参考。