An experimental analysis of inlet flow rate influence on stratification characteristics of a new water storage tank

doi:10.16085/j.issn.1000-6613.2016.02.010

Abstract

Abstract: Water storage tank is widely applied in solar heating systems and domestic electrical water heaters. It is one of the key points which determine the performance of the system and the heater. A better stratification can improve the efficiency of solar heating system and the discharge amount of hot water in electrical water heaters. A new stratifier was designed and installed at the bottom of a cylindrical water storage tank. The test rig was established to measure the stratification characteristics of the tank. The initial temperature of the water in the tank is 50℃,the inlet temperature of the water is 20℃,the flow rate is 0.69L/min,2.14L/min,6.17L/min,respectively. The results showed that,when the larger the flow rate is,the larger is the slope of the sudden change in temperature curves,and the speed of temperature decrease is faster. Based on the thermodynamic laws,extraction efficiency,discharge efficiency and exergy efficiency were used to describe the stratification characteristics of the tank. The results showed that,when the flow rate is 0.69L/min,2.14L/min,6.17L/min,the extraction efficiency is 91.8%,95.7%,94.3%,the discharge efficiency is 96.6%,98.6%,97.5%,the exergy efficiency is 78.5%,83.1%,77.0%.

Key words: water storage tank, stratification, efficiency, exergy, flow, thermodynamics

摘要： 储热水箱被广泛使用在太阳能集热系统以及家用电加热热水器中,是决定集热系统和热水器性能的关键因素之一,储热水箱分层效果越好,越能提高集热系统效率及热水器的热水出水量。本文设计了一种新型均流器,安装在圆柱形储热水箱底部,并搭建了一套储热水箱分层特性测试实验台。在初始水温50℃、进水温度20℃的工况下,分析对比了3组不同流量(0.69L/min、2.14L/min、6.17L/min)时储热水箱的分层特性,结果显示,大流量比小流量温度曲线的斜率更大,温度下降速度更快。同时,基于热力学定律,分别计算了3组流量水箱的取出效率、用能效率、出于能量品质的考虑而采用的(火用)效率,在流量为0.69L/min、2.14L/min、6.17L/min时的取出效率分别为91.8%、95.7%、94.3%,用能效率分别为96.6%、98.6%、97.5%、(火用)效率分别为78.5%、83.1%、77.0%。

关键词: 储热水箱, 分层, 效率, ?, 流动, 热力学

CLC Number:

TK114

WANG Chongyuan, WANG Zilong, ZHANG Hua, CHE Min. An experimental analysis of inlet flow rate influence on stratification characteristics of a new water storage tank[J]. Chemical Industry and Engineering Progree, 2016, 35(02): 403-408.

王崇愿, 王子龙, 张华, 车敏. 进水流量对新型储热水箱分层特性影响的实验研究[J]. 化工进展, 2016, 35(02): 403-408.

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