Nanofluids (CuO & TiO2) - water as heat transfer fluid in a TES system for applications of solar heating - an experimental study

IF 1.1 4区工程技术 Q4 THERMODYNAMICS Thermal Science Pub Date : 2023-01-01 DOI:10.2298/tsci221215080k

Krishna Kondakrindi, M. Reddigari, Hemachandra Konireddy, U. Maheswari

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引用次数: 1

Abstract

The present work aims to exploit the thermal performance of a packed bed of combined sensible & latent heat of storage unit with an integrated solar heat source. A cylindrical insulated storage tank in the Thermal Energy Storage (TES) unit is filled with spherical capsules separately which contains phase change material (PCM) as paraffin wax and stearic acid. The PCM usage has the benefits that it can be used as a thermal management tool and it reduces the cost and size of the system as it offers higher isothermal behavior and thermal storage capacity. The thermal conductivity of heat transfer fluid (HTF) can be enhanced by using nanoparticles mixed in water. Nanofluids are the more efficient fluids for the applications of heat-transfer. The water based nanofluids are used to transfer heat between the solar collector and storage tank which is a sensible heat storage material. The HTF materials are varied and Experimental trials have been conducted separately. Experimentation was carried out First by considering only water as HTF and is extended by adding water with one of the Nanomaterials- i.e.TiO2 and CuO, each in 3 HTF volume % as 0.2, 0.5 & 0.8. The variable source of heat supply considered is Solar flat plate collector. The study was transpired by varying the flow rates of nanofluids as 2.0, 4.0 and 6.0 l/min. The novelty of this work is to envisage the enhancement of heat transfer and to study the effects on the melting time of the PCMs of these fluids which were carried out. The performance parameters like charging time and system efficiency, instantaneous stored heat, cumulative stored heat were studied for the different HTFs and for the PCMs-paraffin and stearic acid. The batch wise process experiments for Discharging were carried out to recover the heat stored, and the results are presented.

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纳米流体(CuO和TiO2) -水作为太阳能加热应用的TES系统中的传热流体-一项实验研究

本研究的目的是利用集成太阳能热源的蓄热机组显潜热复合填充床的热性能。热能储存(TES)装置中的圆柱形绝缘储罐分别充满球形胶囊，其中包含相变材料(PCM)，如石蜡和硬脂酸。使用PCM的好处是，它可以用作热管理工具，它降低了系统的成本和尺寸，因为它提供了更高的等温行为和热存储能力。纳米颗粒掺入水中，可以提高传热流体的导热性。纳米流体是一种高效的传热流体。利用水基纳米流体在太阳能集热器和储热箱之间传递热量，储热箱是一种显热储存材料。HTF材料多种多样，分别进行了实验试验。实验首先只考虑水作为HTF，然后通过加入其中一种纳米材料(即tio2和CuO)进行扩展，每种纳米材料的体积%分别为0.2、0.5和0.8。考虑的可变热源是太阳能平板集热器。研究通过改变纳米流体的流速为2.0、4.0和6.0 l/min进行。这项工作的新颖之处在于设想了传热的增强，并研究了所进行的这些流体的PCMs对熔化时间的影响。研究了不同HTFs以及pcms -石蜡和硬脂酸的加料时间、系统效率、瞬时蓄热、累积蓄热等性能参数。为了回收储存的热量，进行了间歇式放料工艺试验，并给出了试验结果。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Thermal Science 工程技术-热力学

CiteScore

2.70

自引率

29.40%

发文量

399

审稿时长

5 months

期刊介绍： The main aims of Thermal Science to publish papers giving results of the fundamental and applied research in different, but closely connected fields: fluid mechanics (mainly turbulent flows), heat transfer, mass transfer, combustion and chemical processes in single, and specifically in multi-phase and multi-component flows in high-temperature chemically reacting flows processes present in thermal engineering, energy generating or consuming equipment, process and chemical engineering equipment and devices, ecological engineering, The important characteristic of the journal is the orientation to the fundamental results of the investigations of different physical and chemical processes, always jointly present in real conditions, and their mutual influence. To publish papers written by experts from different fields: mechanical engineering, chemical engineering, fluid dynamics, thermodynamics and related fields. To inform international scientific community about the recent, and most prominent fundamental results achieved in the South-East European region, and particularly in Serbia, and - vice versa - to inform the scientific community from South-East European Region about recent fundamental and applied scientific achievements in developed countries, serving as a basis for technology development. To achieve international standards of the published papers, by the engagement of experts from different countries in the International Advisory board.