基于恒热流法和恒温法的岩土热物性试验分析研究

目前岩土热物性测试仪采用的方法包括两种:恒热流法和恒温法,通过介绍两种测试方法的区别及模型算法,以北京市某公建项目岩土热物性测试结果为基准,利用TRNSYS软件分别模拟了恒热流法和恒温法的测试工况,针对模拟结果展开分析研究。经对比,试验时间至48 h时,两种测试方法利用软件模拟出的延米换热量与现场测试结果的误差在10%以内,表明若已知项目周边的地层热物性参数如地层的导热系数、热扩散率等,可将软件模拟结果作为前期地埋管系统设计的依据,并作为后续热物性勘察结果验证的参考数据。此外,根据模拟结果,由于夏季地埋管流体在设计工况下与土壤的温差值较大,为了使流体尽快达到设计工况点,恒温法测试时应选用较大的功率,否则48 h内的测试值结果与实际值偏差较大。

FIBER OPTIC TEMPERATURE MEASURING SYSTEM

This paper presents a fiber optic temperature measuring system used for measuring the temperature in many occasions. The system is of reflective type and composed of thermostatic bimetal plate, lever piston framework, optical grating and optical fiber probes. When the temperature changes, the thermostatic bimetal plate deforms. Through lever piston framework, the optical grating produces displacement in the upright direction. Thus the change of the temperature is transformed into the upright displacement of the optical grating. Optical fiber probes are used for detecting the number of streak lines of the optical grating′s displacement depending on the change of temperature. The detected signal can be transmitted to the control center through optical fiber cable up to distance of 1 km. The measurable range of this system reaches 100℃ with accuracy of ±0.2℃.

基于电子节温器的技术研究和应用

电子节温器是发动机节能减排的重要调节装置之一,它的主要作用是保证冷却液温度在合适的范围内,既要保证发动机不过热,也要防止发动机过冷。同时由于电子节温器具有更快的响应速度和较宽的工作温度范围,可以根据不同的工况的需要,实时不同的控制策略,从而满足发动机智能热管理的需求,达到节能减排的目的。本文结合电子节温器的结构特点和主要特性参数,对电子节温器在发动机上的应用进行归纳、分析和总结,并对未来发展方向进行展望。

零碳智慧社区与零碳经济

随着我国“双碳”建设目标的提出,推动住宅建设向绿色低碳的方向发展。绿色建筑改变了建筑原有的粗放发展模式,转向注重住宅的科技含量、注重建造过程中经济性与运行过程中的效益。本文聚焦绿色建筑中零碳智慧社区的建设方向与技术应用,并阐明这两方面所包含的低碳排放水平与零碳经济的联系,分析零碳智慧住宅与低层住宅的强关联性,规划零碳智慧住宅光伏发电、绿色用能、绿色出行方式,设计应用智慧恒温系统,建立绿色能源互联网以管理家庭产能与调控用能。从经济发展的角度分析可知,零碳智慧社区的建设方向能为建筑行业带来巨大的市场,零碳技术的应用可以为老百姓节约支出的同时带来可观的收益。

发动机冷却系统水流量提升的仿真分析及试验验证

以某发动机为研究对象,建立一维冷却系统仿真分析模型,对发动机的水流量和热平衡进行分析,并进行试验验证。结果表明:通过增加节温器的旁通孔,可以增加发动机的水流量,同时对发动机热平衡影响不大;试验结果与仿真结果一致,水流量和热平衡均满足要求,验证了仿真结果的准确性。

智能PID控制在恒温混匀仪中的应用研究

恒温混匀仪是医学和生物学等领域中常用的仪器,精确的温度控制是确保恒温混匀仪正常工作的关键。本文提出了一种基于TEC(Thermal Electronic Cooler)的智能PID(Proportional Integral Derivative)温度控制系统制,通过离散测量数据库中的多项式回归,对PID常数进行表征,为目标温度选择正确的值。结果表明:该系统的超调小于0.005℃,准确度小于±0.05℃,可确保在不同的环境温度下保持最佳的工作性能,实现最优的温控。

基于时间触发机制的温控负荷集群综合惯性控制研究

面对新型电力系统的低惯量趋势,规模庞大而位置分散的温控负荷在参与电力系统频率响应的同时,能够为电网提供虚拟惯量和一次调频支撑将是提升电网频率安全的新思路。为此,以集中-分布式调控框架下的温控负荷集群为研究对象,首先在详细分解控制层调控中心、协调层聚合商、响应层温控负荷终端三者在辅助调频过程中的采样、计算、控制、执行一系列实时任务的基础上,设计了事件触发与时间触发相结合的温控负荷集群终端异步响应机制,实现温控负荷集群功率遵从综合惯性控制律的效果。随后,对所提综合惯性控制下温控负荷集群参与调频的电力系统进行频率响应建模,并进一步利用改进劳斯近似实现系统降阶,从而获得系统频率响应关键特征的时域解析表达式。最后,通过仿真算例验证了所提基于时间触发机制的温控负荷集群综合惯性控制的有效性,并分析了采用改进劳斯近似对系统模型降阶的可行性。

基于LabVIEW的恒温槽技术性能自动测试系统设计

根据JJF 1030-2010检定规程,对恒温槽温度稳定性和均匀性进行测试。由于测试时间长,人工读数效率低且易出错,因此,本文将HDT1002型高精度测温仪作为电测设备,基于LabVIEW设计开发了恒温槽技术性能自动测试系统。该系统不仅可实现对标准铂电阻温度计读数的自动采集、记录和存储,而且提高了恒温槽技术性能测试的效率和准确性。

Hybrid versus global thermostatting in molecular-dynamics simulation of methane-hydrate crystallisation

Molecular-dynamics(MD)simulations have been performed for the growth of a spherical methane-hydrate nano-crystallite,surrounded by a supersaturated water–methane liquid phase,using both a hybrid and globalsystem thermostatting approach.It was found that hybrid thermostatting led to more sluggish growth and the establishment of a radial temperature profile about the spherical hydrate crystallite,in which the growing crystal phase is at a higher temperature than the surrounding liquid phase in the interfacial region,owing to latent-heat dissipation.In addition,Onsager’s-hypothesis fluctuation–dissipation analysis of fluctuations in the number of crystal-state water molecules at the interface shows slower growth.

Extensive Numerical Tests of Leapfrog Integrator in Middle Thermostat Scheme in Molecular Simulations

Accurate and efficient integration of the equations of motion is indispensable for molecular dynamics(MD)simulations.Despite the massive use of the conventional leapfrog(LF)integrator in modern computational tools within the framework of MD propagation,further development for better performance is still possible.The alternative version of LF in the middle thermostat scheme(LFmiddle)achieves a higher order of accuracy and efficiency and maintains stable dynamics even with the integration time stepsize extended by several folds.In this work,we perform a benchmark test of the two integrators(LF and LF-middle)in extensive conventional and enhanced sampling simulations,aiming at quantifying the time-stepsizeinduced variations of global properties(e.g.,detailed potential energy terms)as well as of local observables(e.g.,free energy changes or bondlengths)in practical simulations of complex systems.The test set is composed of six chemically and biologically relevant systems,including the conformational change of dihedral flipping in the N-methylacetamide and an AT(AdenineThymine)tract,the intra-molecular proton transfer inside malonaldehyde,the binding free energy calculations of benzene and phenol targeting T4 lysozyme L99A,the hydroxyl bond variations in ethaline deep eutectic solvent,and the potential energy of the blue-light using flavin photoreceptor.It is observed that the time-step-induced error is smaller for the LFmiddle scheme.The outperformance of LF-middle over the conventional LF integrator is much more significant for global properties than local observables.Overall,the current work demonstrates that the LF-middle scheme should be preferably applied to obtain accurate thermodynamics in the simulation of practical chemical and biological systems.

Design and Development of New Digital Thermostat

The designed thermostat is based on the microcontroller featuring intelligence, programmable, environmental protection and power saving. The thermostat design is mainly composed of hardware and software design, the hardware includes the power supply circuit, temperature measurement circuit, humidity measurement circuit and backlight circuit; while the software design includes temperature measurement and compensation algorithm, moreover software flowchart is given as well. Finally the power supply circuit is simulated by the software of Pspice and the creative power stealing mode is verified by the simulation results. A target board is stuffed by hand with Pb-free electronic components and used to test hardware and debug software. Since the Pb-free components were used, power stealing mode is designed in hardware and temperature compensation algorithm is accomplished in software, and the thermostat is outstanding with its features of "green" and "power saving".

Numerical distortion and effects of thermostat in molecular dynamics simulations of single-walled carbon nanotubes

In this paper, single-walled carbon nanotubes （SWCNTs） are studied through molecular dynamics （MD） simulation. The simulations are performed at temperatures of 1 and 300K separately, with atomic interactions characterized by the second Reactive Empirical Bond Order （REBO） potential, and temperature controlled by a certain thermostat, i.e. by separately using the velocity scaling, the Berendsen scheme, the Nose-Hoover scheme, and the generalized Langevin scheme. Results for a （5,5） SWCNT with a length of 24.5 nm show apparent distortions in nanotube configuration, which can further enter into periodic vibrations, except in simulations using the generalized Langevin thermostat, which is ascribed to periodic boundary conditions used in simulation. The periodic boundary conditions may implicitly be applied in the form of an inconsistent constraint along the axis of the nanotube. The combination of the inconsistent constraint with the cumulative errors in calculation causes the distortions of nanotubes. When the generalized Langevin thermostat is applied, inconsistently distributed errors are dispersed by the random forces, and so the distortions and vibrations disappear. This speculation is confirmed by simulation in the case without periodic boundary conditions, where no apparent distortion and vibration occur. It is also revealed that numerically induced distortions and vibrations occur only in simulation of nanotubes with a small diameter and a large length-to-diameter ratio. When MD simulation is applied to a system with a particular geometry, attention should be paid to avoiding the numerical distortion and the result infidelity.

Deep Unity of Classic and Quantum Physics at the Space Thermostat Presence with Technical Applications

The paper demonstrates deep unity of classic and quantum physics at the space thermostat (ST) presence, which fulfilled all space by the temperature T0 = 2.73 K. The ST presents itself the Cosmic Microwave Background (CMB). From the main quantum position we consider the ST/CMB as the wave function carrier (“quantum background”). The paper is devoted to ST/CMB medium the classic conservation laws of mass, momentum and energy. We show the soliton like solutions of our classic model correspond to Schrodinger’s quantum solutions, demonstrate the atom hydrogen specter and other quantum peculiarities. The paper contains typical technical examples classic/ quantum simulation at the ST presence.

Numerical Heat Transfer Modelling for Rapid Impact Assessment of Limiting Thermostat Reliability on Fuel-Oil Burner Pre-Heaters： A Case Study

In this paper, the impact of limiting thermostat on the rupture event occuring in Fuel-Oil burner fuel pre-heaters＇ resistant （heat generating） wires is inspected numerically. Gaseous fuel content in the pipeline has also been issued as a possibility. Heater＇s inner temperature distributions have been simulated by an in-house MATrix LABoratory （MATLAB） script in order to understand the resistant wire exposure to high temperatures by numerous scenarios. It is concluded that the effect of fuel flowrate is not a major effect on the wires＇ fate because of the limiting thermostat co-working. The main difference between the calculations is the effect of thermostat cut off function. The numerical simulations enlightened the dominant effect of thermostat sensing delay, so the overheating event. Intolerable delay results with a quick drop in the thermal efficiency and an increased possibility on wire rupture due to overheating which means a burner malfunction. Referring to the first numerical simulation results, a distributed and reduced heat flux was implemented with the same fluid and thermodynamic properties on a revised pre-heater model with an increased heater plate. The increment, thus the reduction on the heat flux of the ribbon wires has been noted as the key for safe operation.

A reinforcement learning approach for thermostat setpoint preference learning

Occupant-centric controls(OcC)is an indoor climate control approach whereby occupant feedback is used in the sequence of operation of building energy systems.While OcC has been used in a wide range of building applications,an OcC category that has received considerable research interest is learning occupants'thermal preferences through their thermostat interactions and adapting temperature setpoints accordingly.Many recent studies used reinforcement learning(RL)as an agent for OcC to optimize energy use and occupant comfort.These studies depended on predicted mean vote(PMV)models or constant comfort ranges to represent comfort,while only few of them used thermostat interactions.This paper addresses this gap by introducing a new off-policy reinforcement learning(RL)algorithm that imitates the occupant behaviour by utilizing unsolicited occupant thermostat overrides.The algorithm is tested with a number of synthetically generated occupant behaviour models implemented via the Python APl of EnergyPlus.The simulation results indicate that the RL algorithm could rapidly learn preferences for all tested occupant behaviour scenarios with minimal exploration events.While substantial energy savings were observed with most occupant scenarios,the impact on the energy savings varied depending on occupants'preferences and thermostat use behaviour stochasticity.

考虑群体热适应性的楼宇综合能源系统规划

充分发挥楼宇综合能源系统能源生产侧与消费侧源荷互动特性的作用,需要由供能的舒适度来保证。基于群体热舒适感会随季节调整其对环境的热期望的热适应性原理,建立楼宇综合能源系统中的能量枢纽选型定容统一优化模型。模型计及典型日室外温度、光照辐射强度和刚性电热负荷对室内温控负荷及能量枢纽出力的影响,将室温调节策略和能量枢纽容量配置基于群体热环境舒适区间进行约束,实现楼宇热舒适供能与能量枢纽架构经济性的协同优化,并采用Benders分解方法加以求解。算例分析结果表明,对热舒适区间进行修正后的规划模型能减少能量枢纽的配置容量,可有效提高可再生能源利用率并降低系统整体的碳排放量。

调温器在汽车冷却系统中的应用

作为现代的燃油发动机制冷系统有两大作用:尽快使发动机达到适宜的工作温度,排出运行过程中产生的多余热量。因此,冷却系统能迅速提供平稳的运转环境,使其高效运转、降低排放污染,进而延长发动机寿命。调温器作为冷却系统的关键零部件,合理的参数设计显得尤为重要,并越来越受到设计人员的重视。本文以调温器感应体设计为重点,介绍了普通调温器和电子调温器的设计。

用于检测生化需氧量的恒温系统设计

针对目前检测生化需氧量过程中没有维持检测体系恒温的问题,设计并制作了一个以STM32F103RCT6单片机为控制核心的用于检测生化需氧量的恒温系统。通过防水型PT100温度传感器采集恒温装置内的水浴温度,同时利用嵌入式实时操作系统FreeRTOS通过PID算法控制PWM占空比对水浴温度进行分段闭环加热控制,并将实时温度显示在上位机界面,有效解决了温度对检测生化需氧量过程的干扰问题,保证了检测的稳定性和准确度。

基于单片机的太阳能储能智能恒温外卖柜设计

近来国内各地疫情频出,人们的饮食方式也随之改变,外卖愈发成为更多人的选择,针对外卖的保温问题,设计了一种基于STC89C52RC为控制核心的智能恒温外卖柜。该装置利用太阳能储能元件驱动单片机,通过温度传感器检测箱内温度并进行控制,并且利用键盘、LCD1602液晶显示器、NRF24L01无线传输模块等实行智能操作。实验结果表明,基于此单片机的恒温外卖柜,减少了人力成本,实现了智能控制。

柴油机高温冷却水温度控制系统的设计与仿真

在柴油机高温冷却水的温度处于设定值和上、下限值区间时,对三通恒温阀口随水温状态的动作进行逻辑分析,并通过Proteus V7.8软件进行仿真验证。当水温在设定值和上、下限值区间时,针对柴油机高温冷却水系统,将基于改进粒子群优化的PID(比例积分微分控制,proportional plus integral plus derivative control,简称PID)算法与传统PID算法进行温度控制仿真试验并对比,给出具体的控制系统设计方案,实现对三通恒温阀开度的控制,从而改变柴油机冷却水系统出机高温水进入淡水冷却器的旁通量,进一步调节高温冷却水的进机温度,最终实现高温冷却水出机温度稳定。