小型家用空调器除霜方式的探讨

提高低温制热量是小型家用空调器技术的一个难点,除霜带来的热量损失是低温制热量损失的一个重要方面。对小型家用空调器的除霜技术的发展进行了分析和总结,对小型家用空调器提出了一些新的除霜方式,对提高空调器的低温制热量、使用性能有重要意义。     

相同条件下定频、变频空调节能舒适性对比试验研究

在焓差实验室中模拟家用空调器的实际运行环境,相同条件下对比研究相同制冷量的定频和变频空调器的节能舒适特性。结果表明:相同条件下定频空调器能使室内更早的达到设定温度,当空调器设定温度16℃,室外温度35℃时,定频和变频空调器的耗电量达到相同的时间为11h,室外温度为40℃时,定频和变频空调器的耗电量达到相同的时间为6.3h,室外温度越高,定频和变频空调器耗电量相同的时间越提前,变频空调器需要更长的时间才能体现出节能优势;室外温度35℃时,运行变频和定频空调器,室内不同高度之间的温差分别在0.2℃~0.5℃和0.7℃~1℃,室内温度波动周期分别为2.4h和0.25h,变频空调器温差低于定频空调器,且波动周期大,室内温度变化缓慢,舒适性优于定频空调器。     

带冷凝热回收的家用空调器的研究

随着生活水平的提高,家用空调器的使用逐年增加.空调器在夏季向室内供冷的同时,不仅给室外环境造成了热污染,而且还造成了能源的浪费.因此,很多学者都提出了空调冷凝热回收理论并进行了实验研究.文中分析了在家用空调器回收冷凝热的可行性及研究现状;介绍了家用空调器采用的冷凝热回收系统的形式及其分类;提出了一种带冷凝热回收装置的多...     

可燃制冷剂空调器性能测试实验室的研制

依据国家标准GB/T7725-2004《房间空气调节器》、GB/50016-2006《建筑设计防火规范》和上海出入境检验检疫局技术协议要求,设计并建造一套可燃制冷剂空调器性能测试实验室。目前,国内主要采用空气焓值法对空调器进行其性能的测试。为了保护臭氧层及降低温室效应,现代制冷工业以逐渐开始用环境友好型碳氢化合物制冷剂取代传统制冷剂,并已在家用空调器中逐渐开始使用。     

风源热泵空调器除霜技术实验研究

风源热泵空调器的结霜问题和除霜控制技术受到制冷与空调领域学者的广泛关注。文中重点对普遍采用时间温度法除霜控制技术的家用空调器制热运行时 ,结霜和除霜过程进行了深入地实验研究。结果表明 ,在较宽的气候变化范围 ,该控制方法工作不可靠 ,容易出现除霜不净和过早除霜的现象。提出了能适应气候变化的模糊自修正除霜技术的设计思想。     

车载空调器设计平台研究与开发

针对车载空调器设计手工计算繁琐、设计周期长等诸多不便利特点,研制开发了基于VB和SOLIDEDGE软件的车载空调器设计平台。该平台不仅具有车载空调器整机开发、机组设备单独设计或选型以及换热器参数化设计的功能,还兼容了家用空调器设计开发的能力。平台运行平稳,结果直观可靠。     

焓差试验室基于全自动运行的节能改造

介绍了焓差法空调器性能测试装置的基本构造,在此基础上作者提出了对原试验装置进行全自动以及节能改造的方案,并对测控软件进行了二次开发。改造结果表明,该方案提高了试验室的测试效率,降低了试验人员的工作强度,同时也降低了试验室运行能耗。     

多变环境条件下家用空调器性能的研究进展

从区域性、变工况条件下空调器性能变化和空调器对室内温度分布的影响三个方面对家用空调器性能的研究现状进行了综述和分析,并对分析方法和试验方法进行了改进。分析方法上引入相对制冷量比率(Relative Refrigerating Capacity Percentage,RRCP)、相对制热量比率(Relative Heating Capacity Percentage,RHCP)、相对功率比率(Relative Power Percentage,RPP)和相对能源消耗比率(Relative Energy Consumption Percentage,RECP),分析空调器实测性能与名义性能参数的关系。并提出室外侧温度保持不变,室内侧空调自由运行,室内由初始温度降至空调设定温度的试验方法,此种方法可以对比分析定频空调和变频空调在相同条件下的耗电量和对室内温度分布的影响。     

多变环境条件下家用空调器性能的研究进展北大核心

从区域性、变工况条件下空调器性能变化和空调器对室内温度分布的影响三个方面对家用空调器性能的研究现状进行了综述和分析,并对分析方法和试验方法进行了改进。分析方法上引入相对制冷量比率(Relative Refrigerating Capacity Percentage,RRCP)、相对制热量比率(Relative Heating Capacity Percentage,RHCP)、相对功率比率(Relative Power Percentage,RPP)和相对能源消耗比率(Relative Energy Consumption Percentage,RECP),分析空调器实测性能与名义性能参数的关系。并提出室外侧温度保持不变,室内侧空调自由运行,室内由初始温度降至空调设定温度的试验方法,此种方法可以对比分析定频空调和变频空调在相同条件下的耗电量和对室内温度分布的影响。     

不同工质房间空调器的冷凝水应用对能效比的影响

本文在对比分析风冷和蒸发式冷却方式的优缺点后,从房间空调器冷凝水应用这个角度,分析正在使用的和将来可能替代使用的五种不同工质:R22、R32、R410A、R134a、R290,其应用冷凝水对能效比的影响。经理论计算比较,房间空调器应用冷凝水能效比提高,最大达17.81%,为工质R410A;最小为12.87%,为工质R32;能效比平均提高15%,节能效果比较明显。因此冷凝水利用技术对工质为R410A的房间空调器更值得推广。     

Time-dependent behavior of a pulsed high power xenon flashlamp. Application to the Mega-Joule laser pumping

A numerical model has been developed for studying the time-dependent behavior of cylindrical high power xenon flashlamp. The equations of local energy conservation and mass conservation are solved using the finite volume method to give plasma parameters such as radial temperature profiles, instantaneous emission spectra, pressure, velocity, arc conductance, etc. In a first approximation the plasma is described under local thermodynamic equilibrium, LTE. The results are given as a function of time over the pulse and for several nodes in the cross section. Then the detailed spectral and temporal calculations of the output radiation from xenon flashlamp and radiation efficiencies are provided.     

The density of energy flow of quasiparticles with arbitrary energy–momentum relation

In this paper, we consider the energy conservation law in a continuous medium with arbitrary energy–momentum relation. We use a new theoretical approach in which both the long wavelength and short wavelength thermal excitations are described in a unified way. The theory is based on the fact that in a quantum fluid, the thermal de Broglie wavelengths of the atoms overlap each other. In this case, the atoms are delocalized in space and we can treat a quantum fluid as a continuous medium without any restriction on length scale. So, in quantum liquids, we can determine the probabilistic values of the parameters of the continuous medium in every mathematical point of space. From the Hamiltonian of this system, we derive a system of linear equations for the general case of an ideal liquid, which has a nonlocal relationship between pressure and density. In the frame of this model from the energy conservation law, a general expression for the energy density flow is obtained. It is shown that for the wave packet, it is not affected by the freedom in its definition. A clear relation for the energy density flow of a wave packet is derived that generalizes the ordinary form of it to the case of arbitrary dispersion.     

Charged Particles’ Tunneling from Hot-NUT-Kerr-Newman-Kasuya Spacetime

We study the Hawking radiation as charged particles’ tunneling across the horizons of the Hot-NUT-Kerr-Newman-Kasuya spacetime by considering the spacetime background as dynamical and incorporating the self-gravitation effect of the emitted particles when the energy conservation, the angular momentum conservation, and the electric charge conservation are taken into account. Our result shows that the tunneling rate is related to the change of Bekenstein-Hawking entropy and the radiant spectrum is not pure thermal, but is consistent with an underlying unitary theory. The emission process is a reversible one, and the information is preserved as a natural result of the first law of black hole thermodynamics. To my teacher late Prof. Mainuddin Ahmed.     

Weak Solutions of the Boltzmann Equation Without Angle Cutoff

The definition of the concept of weak solution of the nonlinear Boltzmann equation, recently introduced by the author, is used to prove that, without any cutoff in the collision kernel, the Boltzmann equation for Maxwell molecules in the one-dimensional case has a global weak solution in this sense. Global conservation of energy follows.     

对一道力学习题解法的剖析

通过一道经典的力学习题的分析,考察内力的不同作用效果,指出加深理解物理规律适用条件的重要性.     

相对论电子束在磁化等离子体中的能量损失

本文研究了相对论电子束(REB)在磁化等离子体中的能量损失。导出了REB能量损失的一般表达式,并用数值方法分析了能量损失与参量之间的关系。结果表明,在一定的参数范围内,磁场对REB能量损失有极重要的影响。     

分段表面放电沉积效率研究

 利用一种结构紧凑的分段表面放电辐射源模块，详细研究了在不同电压、电容、气压实验条件下回路等效电阻、等效电感及放电能量沉积效率的变化规律，利用四分幅相机拍摄获得了不同实验条件下的放电等离子体通道图像，分析讨论了放电等离子体运动对放电能量沉积效率的影响，提出了提高能量放电沉积效率的有效途径。     

分级再生式转轮除湿空调系统的性能分析

提出了分级再生式转轮除湿和蒸发冷却相结合的空调系统,依据除湿和再生过程的质量守恒和能量守恒方程,结合边界条件和初始条件建立除湿转轮和空调系统的数学模型,对比分析了分级再生空调系统的性能。研究结果表明:采用分级再生的转轮可达到与一般再生转轮相同的除湿效果。与一般再生的空调系统相比,分级再生式空调系统的再生能耗降低了约50%,热力性能系数提高了约90%。     

不同超声作用方式对葛根有效部位提取率的影响

研究不同的超声作用方式对葛根总黄酮的提取率的影响.采用单频,双频（包括槽式双频以及槽式＋探头式双频）,及三频等不同的处理方法,对超声作用参数,如时间,声强及处理量的多少进行研究,采用两个超声特性参数即能量效率和空化产量来对比不同容积、频率的超声作用效果.目前的研究表明：多频超声耦合时,可以获得较高的能量效率和空化产量.     

Joint user grouping and power allocation in VLC-NOMA system

With the energy consumption of wireless networks increasing, visible light communication (VLC) has been regarded as a promising technology to realize energy conservation. Due to the massive terminals access and increased traffic demand, the implementation of non-orthogonal multiple access (NOMA) technology in VLC networks has become an inevitable trend. In this paper, we aim to maximize the energy efficiency in VLC-NOMA networks. Assuming perfect knowledge of the channel state information of user equipment, the energy efficiency maximization problem is formulated as a mixed integer nonlinear programming problem. To solve this problem, the joint user grouping and power allocation (JUGPA) is proposed including user grouping and power allocation. In user grouping phase, we utilize the average of channel gain among all user equipment and propose a dynamic user grouping algorithm with low complexity. The proposed scheme exploits the channel gain differences among users and divides them into multiple groups. In power allocation phase, we proposed a power allocation algorithm for maximizing the energy efficiency for a given NOMA group. Thanks to the objective function is fraction form and non-convex, we firstly transform it to difference form and convex function. Then, we derive the closed-form optimal power allocation expression that maximizes the energy efficiency by Dinkelbach method and Lagrange dual decomposition method. Simulation results show that the JUGPA can effectively improve energy efficiency of the VLC-NOMA networks.