1-D transient numerical model of a regenerator in a novel sub Kelvin Active Magnetic Regenerative Refrigerator

A sub Kelvin Active Magnetic Regenerative Refrigerator (AMRR) is being developed at the University of Wisconsin – Madison. This AMRR consists of two circulators, two regenerators, one superleak, one cold heat exchanger, and two warm heat exchangers. The circulators are novel non-moving part pumps that reciprocate a superfluid mixture of ⁴He–³He in the system. Heat from the mixture is removed within the two regenerators of this tandem system. An accurate model of the regenerators in this AMRR is necessary in order to predict the performance of these components, which in turn helps predicting the overall performance of the AMRR system. This work presents modeling methodology along with results from a 1-D transient numerical model of the regenerators of an AMRR capable of removing 2.5 mW at 850 mK at cyclic steady state.     

新型双温驱动吸收制冷循环性能

针对跨临界CO_2压缩制冷系统制取冷量以消耗高品位能量为代价的问题,本文依据能量梯级利用原理,提出双温低品位热源驱动的新型CO_2-[emim][Tf_2N]吸收式制冷循环的新流程,在构建该制冷循环数学模型的基础上,搭建测试双温驱动吸收制冷循环性能的实验装置,利用模拟和实验方法分析了操作参数对系统性能的影响规律。在定流量的条件下,研究驱动热源温度、冷却水入口温度以及载冷剂入口温度等操作参数对新系统性能的影响规律,结果表明双温驱动新型吸收制冷系统不仅可实现高效制冷,而且最低制冷温度可达到-15.2℃,研究结果为CO_2-离子液体制冷系统的理论设计计算提供实用的数据基础。     

采用变回水温度控制策略的空气源热泵空调系统研究

为了提高空气源热泵空调系统运行性能,研究了一套采用变回水温度控制策略的空气源热泵机组的制冷性能。实验研究表明,变回水温度工况可满足室内冷负荷需求。与传统采用定12℃回水温度的空气源热泵空调系统相比,COP更高,耗电量更小,是一种高效节能的空气源热泵空调系统控制方法。此外,所建立的Dymola模型从理论上验证了实验结果,在此基础上模拟实际空调系统的能耗,模拟结果表明,COP由3.99提高至4.39,提高了10%。     

基于13X沸石分子筛/MgCl_2的复合吸附剂性能实验研究

复合吸附剂的吸附性能是吸附制冷循环过程中的一个重要参数,基于测试整体成型复合吸附剂吸附性能的需要,本文设计搭建了一种整体成型吸附剂性能测试装置,对复合吸附剂MgCl_2-13X进行了吸附性能测试实验。结果表明:该实验装置中吸附床外侧底部的温度变化速率较接近吸附床内部底部吸附剂的温度变化速率,二者温度变化速率相差0.01~1.9℃/min,整个吸附和脱附过程二者温度的平均值相差约3.24%,能够满足吸附剂性能测试实验的要求。吸附剂性能测试实验及电镜下吸附剂的微观结构表明:浸泡法制备的复合吸附剂的吸附性能与MgCl_2溶液的浓度有关,MgCl_2能够改善13X沸石分子筛的吸附性能,本实验测得当MgCl_2溶液的浓度为15%时所制得复合吸附剂MX3性能最优,其最大吸附量为0.32 g/g,最大吸附速率0.59 g/min,相比单一吸附剂13X沸石分子筛提高了20%。     

磁制冷材料的研究进展

本文简述了磁制冷的基本原理,分析磁制冷工质的熵特性,总结了近几年磁制冷材料的最新进展,对磁制冷材料未来的发展进行了展望。     

Inorganic-Based Printed Thermoelectric Materials and Devices

One of the simplest ways to generate electric power from waste heat is thermoelectric (TE) energy conversion. So far, most of the research on thermoelectrics has focused on inorganic bulk TE materials and their device applications. However, high production costs per power output and limited shape conformity hinder applications of state-of-the-art thermoelectric devices (TEDs). In recent years, printed thermoelectrics has emerged as an exciting pathway for their potential in the production of low-cost shape-conformable TEDs. Although several inorganic bulk TE materials with high performance are successfully developed, achieving high performance in inorganic-based printed TE materials is still a challenge. Nevertheless, significant progress has been made in printed thermoelectrics in recent years. In this review article, it is started with an introduction signifying the importance of printed thermoelectrics followed by a discussion of theoretical concepts of thermoelectricity, from fundamental transport phenomena to device efficiency. Afterward, the general process of inorganic TE ink formulation is summarized, and the current development of the inorganic and hybrid inks with the mention of their TE properties and their influencing factors is elaborated. In the end, TEDs with different architecture and geometries are highlighted by documenting their performance and fabrication techniques.     

真空冷冻干燥装置制冷系统的设计

基于真空冷冻干燥装置的推广应用,讨论了该装置制冷量的确定方法,给出了常见冻干食品的蒸发温度为－３５～－４０℃,可满足其降温要求,介绍了该装置近阶段优先选择的制冷剂为Ｒ７１７、Ｒ２２,优先选择的制冷机为单、双机压缩冷凝制冷机组,或带经济器的螺杆式低温压缩机组,为进一步工程应用提供设计依据     

基于单片机和半导体制冷效应的高效聚能系统

反向利用半导体制冷片的功能,以生活废热水热能回收为例设计了一套模拟实验装置,其主体结构包括废热水箱和纯净水箱,在两水箱中间放置5片制冷片,其中制冷片的冷端接触进水箱,热端接触出水箱,采用ATmega16L单片机控制,通过设定水温,使纯净水和废热水达到预设温度后排放,实现能量聚集与转换的功能。     

热电致冷的激光器温度控制电路设计

设计了一种高精度、外围元件较少的热电致冷温度控制电路。介绍了激光器温度控制电路的系统组成及工作原理,重点论述了采用基于TPS63000的热电致冷控制电路,通过MCU的数字PID控制算法对EML激光器温度进行精确调节的过程。实验结果表明,该电路完全符合EML激光器对温度稳定性的要求。