太阳能热泵地板辐射供暖系统

太阳能热泵低温地板辐射供暖系统是将太阳能、水源热泵和地板供暖结合在一起的新型采暖方式。介绍了太阳能热泵低温地板辐射供暖系统的工作原理和构成,并以青岛地区为例,设计了太阳集热器、蓄热器、地板换热盘管等设备,探讨了系统的设计方法。     

低温地板辐射采暖传热特性研究

为了揭示低温地板辐射供暖的传热特性,利用Fluent软件和k-ε湍流模型对低温地板辐射采暖系统的温度场进行数值模拟.搭建电热地板辐射采暖实验系统,进行室内温度场的测量和数值模拟,通过实验测试值及模拟值的对比分析,验证数值模拟的正确性.建立低温热水地板辐射采暖物理模型,对不同供水流速和供水温度进行地面温度分布、地板层温度...     

低温热水地板辐射采暖的(火用)分析

本文建立了采暖系统的分析模型 ,利用所建立的模型 ,对地板辐射采暖和传统的散热器采暖两种采暖方式进行了分析。结果表明 ,当地板辐射采暖的供回水温度为 4 5℃ 35℃时 ,与传统的散热器采暖相比 ,其效率大约高 18% ,地板辐射采暖所需供水温度低 ,可以充分利用各种低温热源及工业废热等低品位能量 ,是一种具有发展潜力的节能型采暖方式     

低温热水地板辐射采暖的Yong分析

本文建立了采暖系统的Yong分析模型，利用所建立的模型，对地板辐射采暖和传统的散热器采暖两种采暖方式进行了Yong分析。结果表明，当地板辐射采暖的供回水温度为45℃／35℃时，与传统的散热器采暖相比，其Yong效率大约高18％，地板辐射采暖所需供水温度低，可以充分利用各种低温热源及工业废热等低品位能量，是一种具有发展潜力的节能型采暖方式。     

太阳能地板辐射采暖系统在连续运行时的系统特性研究

通过实验研究了在一定集热面积和采暖面积比前提下,太阳能地板辐射采暖系统在连续运行时的一些系统特性,主要包括系统的太阳能保证率、地板进出水温度、房间空气温度、地板换热量以及热舒适性指标,用TRNSYS软件对实验系统进行模拟,得出地板层构造对系统性能的影响规律以及服装热阻对热舒适性的影响规律.     

太阳能热泵低温地板辐射供暖系统的研究与展望

太阳能热泵低温地板辐射采暖系统是以太阳能热泵为热源,以地板辐射采暖系统为末端装置的新型供暖系统.本文综述了太阳能热泵在国内外的研究与应用,并阐述了太阳能热泵低温地板辐射供暖系统的工作原理及在国内的研究现状.分析了该系统的特点,结果表明该系统是一种舒适、经济和节能的理想供热系统.本文还探讨了该系统在当前的应用中尚待解决的问题.     

太阳能—低温热管地板辐射供热系统实验研究

为将低品位太阳能直接应用于建筑供暖,对一种太阳能-低温热管地板辐射供暖系统进行了实验研究.在天津地区冬季条件下、供水温度为35～45℃时,针对非节能建筑的房间负荷(30～60 W/m2)进行了该系统各部件和系统整体性能的实验.实验结果表明:供水温度35～45℃即可满足采暖要求;太阳能保证率受供水温度影响显著,供水温度升高10℃,太阳能瞬时保证率减小5%;晴朗白天,室外平均温度-0.72℃,平均太阳辐照度425.1 W/m2,太阳能瞬时保证率近似为1;阴天室外平均温度-1.55℃,平均太阳辐照度220.5 W/m2,太阳能瞬时保证率随供水温度和负荷的变化而变化,范围是0.52～0.96.实验证实:该系统能提高太阳能热利用的经济性,热管地板传热性能优于塑料埋管地板,供水温度可以比常规塑料埋管地板的要求降低约5℃.     

室内低温热水地板辐射供暖系统的节能分析

本文阐述了低温热水地板辐射采暖分户热计量系统是一种易控、易调、节能的采暖系统,讨论了地板辐射供暖方式与其他方式在房间内人体热舒适方面的差异,并通过对其综合节能效果的考察,分析了地板辐射供暖系统不稳定供暖过程的数学模型,用数值计算的方法分析了间歇供暖条件下,达到室内要求温度所需的预热量与预热时间的关系。     

基于计算机仿真的低温地板辐射采暖系统的节能性分析

介绍了基于空间热网模型的采暖系统的计算机仿真程序，并运用该程序对低温地板辐射采暖和对流采暖两种系统进行计算机仿真，通过对一个采暖日内两种采暖方式下房间的采暖负荷、室内平均空气温度和维护结构内表面温度的动态分析和比较，证明了在维持房间相同热舒适度的情况下，低温地板辐射采暖系统的采暖负荷比对流采暖系统的采暖负荷小，具有节能性。     

不锈钢波纹管地板辐射采暖热工性能研究

建立不锈钢波纹管地板辐射采暖传热数学模型,并运用ANSYS有限元分析软件对模型进行求解。通过在标准测试闭式小室中进行实测,验证所建立数学模型的准确性。对比分析采用不锈钢波纹管、传统PE-X管和PB管的地板辐射采暖系统的热工性能,结果表明:采用不锈钢波纹管可有效地提升地板辐射采暖系统的供热量,但也会导致地板表面温度的不均匀分布。故推荐不锈钢波纹管地板辐射采暖系统采用比传统塑料管地板辐射采暖系统低的供水温度,既可满足热负荷要求,亦可降低地板表面温度分布的不均匀度,还可采用低品位热源,实现节能降耗。     

余热回收用热管及热管式换热器的研究

简要介绍了热管及热管式换热器的工作原理,热管式换热器在工业余热回收中的应用,以及热管式换热器运行过程中防止积灰和低温腐蚀等问题的有效措施。     

On the steady‐state modelling of a two‐stage evaporator system

We develop and validate against experimental measurements a steady‐state two‐stage flooded refrigerant evaporator model for a heat pump drying system. A prototype two‐stage heat pump dryer test facility was designed, built and instrumented to provide the required measurements for the validation of the model. Repeatability and data quality tests were conducted to evaluate the accuracy of measurements. Experimental data could be reproduced to within ±6.5 per cent of replicated air and refrigerant side measurements for the same evaporator's air inlet conditions while the discrepancy of energy balance at the air‐side and refrigerant‐side was observed to be within ±8.9 per cent. The two‐stage evaporator model predicted the air‐side total heat and latent heat transfer of the two‐stage evaporator to within (?6.3 per cent, 7.6 per cent) and (?11.5 per cent, 9.5 per cent), respectively. On the refrigerant‐side, the model enabled the calculation of the degree of superheat to within (?10.6 per cent, 1.7 per cent). The model has shown that there is significant improvement in the heat recovered from a two‐stage evaporator system compared to a single evaporator system. In addition, the model demonstrated that the improvement in total heat recovery could be as high as 40 per cent over its base‐value when the latent to total load at the two‐stage evaporator is increased. Copyright © 2001 John Wiley & Sons, Ltd.     

显热储热材料的制备及性能研究

采用水泥作为材料的胶凝剂,添加热容、热导率大的物质作为骨料来制备混凝土储热材料。研究表明:当铝酸盐水泥含量为10%时,材料的抗压、抗折强度能满足工业需求;材料的比热容随温度的升高先增大,在500℃时达到最大,后随着温度的升高反而降低;材料的热导率随着石墨粉含量的增加几乎成直线上升,当石墨含量为5%时材料的热导率大于1.7W/(m·K)。     

间歇式热处理炉传热计算与分析

建立了台车式热处理炉炉膛传热数学模型和辐射换热器工作模型,分析了换热器的传热特性（空气预热温度、壁温、传热系数）随炉况的变化。结果表明,辐射换热器的传热特性随炉子的升温及保温过程变化而波动很大,因而对炉子的热工性能产生了影响。     

Quantification of the European industrial heat demand by branch and temperature level

We present the first comprehensive estimate of the final energy demand for heat in all EU28 member states for the reference year 2012, differentiated by temperature levels, comparing two different approaches. Two different calculation approaches based on different data sets yielded estimates of the total final energy demand for heat in the EU28 of 8150 PJ and 8518 PJ in 2012, respectively. Approach 1 distinguishes between three different process heat (PH) temperature levels and results in final energy demand for heat <100°C: 2077 PJ, 100–400°C: 2214 PJ and >400°C: 3859 PJ. The second approach distinguishes between low temperature space heat and hot water (<100°C: 1161 PJ) and four different PH temperature levels with a resulting energy demand of <100°C: 1027 PJ, 100–500°C: 1785 PJ, 500–1000°C: 1679 PJ and >1000°C: 2865 PJ. The high share of high‐temperature heat illustrates the limits to the potential decarbonisation of industrial thermal processes with renewable energy sources such as (non‐concentrating) solar thermal, geothermal or environmental heat. Therefore specific information on required temperature levels is of the essence. This, in turn, points out the relevance of renewable electricity and synthetic fuels based on renewable power for a significant reduction of CO₂ emissions from the industry sector in Europe. Considering current data quality, it is recommended to develop a consistent, comprehensive methodology to significantly improve the data basis on industrial heat demand. Copyright © 2015 John Wiley & Sons, Ltd.     

Heat pump dryer Part 1: Simulation of the models

Heat pump dryer is a complex system because of the interaction of heat and mass transfer of the working fluids. Since the system cannot be completely close, ambient conditions (temperature and humidity) influence the performance of the system. To investigate the performance of the heat pump dryer thoroughly, simulation models of heat pump dryer components have been developed. The finite-difference method was employed in the simulation to examine the state of the working fluids and heat and mass transfer. The simulation of each component can be used to construct different system configurations the results of which are reported in Part 2.     

国内分离式热管概况与热环研究的小结及展望

本文对我国分离式热管技术的研究进行了简要概况,针对工程中热源在上,冷源在下及冷热源相距较远时的热量传递问题,在分析了一般分离式热管及“水回路”等技术的基础上,对一种新型分离式热管－泵或风机驱动的动力型分离式热管（简称热环）的研究进行了小结和展望。     

Field test of a novel combined system of a high-efficiency heating/cooling heat pump and a clathrate cool storage unit

The Research Laboratory of Kyushu Electric Power Co., Inc. (KEPCO) installed a novel system in March 1992 which is a combination of a super heat pump with about twice the performance of a conventional one and a compact chemical storage-type clathrate cool storage unit. A field test was implemented by integrating these units into an actual air-conditioning system. As a result of the test, system performance was determined and the effectiveness of the system was confirmed. © 1998 Scripta Technica. Heat Trans Jpn Res, 26(6): 410–418, 1997     

Augmentation of heat transfer through passive techniques

The thermal performance of energy preservation systems is greatly improved by increasing miniaturization and boosting. These are imaginative (or Promethean) techniques to enhance heat transfer. Enhancement methods of heat transfer draw great attention in front of the industrial sector because of their ability to provide energy savings and raise the economic efficiency of thermal systems. Three techniques these methods are categorized; those are active, passive, and compound. Different types of components are used in passive methods because of the transfer/working fluid flow path to the enhancement of the heat transfer rate. In this article, the subject of the review was the passive heat transfer enhancement methods including inserts (conical strips, winglets, twisted tapes, baffles), porous materials, coil/helical/spiral tubes, rough surfaces (corrugated/ribbed surfaces), extended surfaces (fins) and nanofluids (mono and hybrid nanofluid). Recent passive heat transfer enhancement techniques are studied in this article as they are cost-effective and reliable, and also comparably passive methods do not need any extra power to promote the energy conversion systems' thermal efficiency than active methods. In the passive approaches, various components are applied to the heat transfer/working fluid flow path to improve the heat transfer rate. The passive heat transfer enhancement methods studied in this article include inserts (twisted tapes, conical strips, baffles, winglets), extended surfaces (fins), porous materials, coil/helical/spiral tubes, rough surfaces (corrugated/ribbed surfaces), and nanofluids (mono and hybrid nanofluid). From the pioneers' research work, it is clear that a lower twist ratio and lower pitch, lesser winglet angles can provide more heat transfer rate and a little bit more friction factor. In the case of nanofluids, a little bit of pumping power is enhanced. Finally, heat transfer enhancement is compared with the thermal performance factor, which is more than unity.     

Heat-spreading analysis of a heat sink base embedded with a heat pipe

A simplified model predicting the heat transfer performance of a heat sink base with a high thermal conductivity was developed. Numerical analysis was performed using the commercial software FLUENT. The investigation indicates that for heat sink bases with a high effective thermal conductivity, such as the base embedded with a typical heat pipe, the entire heat sink can be modeled as a flat plate with a uniform temperature and an effective convection heat transfer coefficient. This simplified model can be used to determine the heat transfer performance of a heat sink embedded with a typical heat pipe or vapor chamber.