scholarly journals Experimental Analysis of Thermal Stratification in a Heat Storage Tank Using Stratification Pipe

2009 ◽  
Vol 3 (3) ◽  
Author(s):  
A. Boloņina ◽  
C. Rochas ◽  
D. Blumberga
Keyword(s):  
Experimental Analysis ◽  
Storage Tank ◽  
Thermal Stratification ◽  
Heat Storage

Influence of inlet structure on thermal stratification in a heat storage tank with PCMs: CFD and experimental study

2019 ◽  
Vol 162 ◽  
pp. 114151 ◽  
Author(s):  
Zilong Wang ◽  
Hua Zhang ◽  
Binlin Dou ◽  
Guanhua Zhang ◽  
Weidong Wu
Keyword(s):  
Experimental Study ◽  
Storage Tank ◽  
Thermal Stratification ◽  
Heat Storage

The Thermal Stratification Evaluation of Phase-Change Materials in a Heat Storage Tank: Computational Fluid Dynamics and Experimental Study

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Zilong Wang ◽  
Hua Zhang ◽  
Binlin Dou ◽  
Guanhua Zhang ◽  
Huajie Huang
Keyword(s):  
Experimental Data ◽  
Phase Change ◽  
Flow Velocity ◽  
Storage Tank ◽  
Thermal Stratification ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Discharge Process ◽  
Dimensionless Time ◽  
Flow Rates

Abstract The heat storage technology can improve the performance of a solar thermal utilization system effectively. This work studied the effect of phase-change materials (PCMs) on thermal stratification in a heat storage tank. A 60 l sodium acetate trihydrate heat storage tank with 331.15 K phase-change temperature was designed and fabricated. A mathematical model was built to simulate the discharge process in the water tank, and the temperature distribution during the discharge process was obtained. The computational fluid dynamics model was verified by the experimental data. Furthermore, the Ri, the fill efficiency, and the MIX number were adopted to extensively analyze the performance of a heat storage tank with different positions of PCMs with the variation of flow rates. The results indicated that the distance between the isothermal surfaces of 303.15 K and 348.15 K in PCM1, PCM2, PCM3, and PCM4 were 11.75 cm, 11.13 cm, 10.52 cm, and 9.28 cm, respectively, with 9 l/min of flow velocity when t* = 0.7, showing that the thermal stratification was improved as the position of the PCMs got closer to the inlet. The PCMs’ half-life (the liquefaction rate reached 50%) was prolonged as the inlet flow rates increased. As the flow rate increased from 1 l/min to 5 l/min, the half-life of PCM4 delayed from a dimensionless time of 0.5 to a dimensionless time of 0.9. Moreover, when the flow velocity was 9 L/min, the liquefaction rate of PCM4 remained at 1. The calculated values of fill efficiency and Richardson number were higher than the experimental data slightly, while the MIX number was smaller than the experimental results. The experimental and calculated values of root mean square error (RMSE) increased with the increasing inlet flow velocity and the lowering of the positions of the PCMs.

scholarly journals Experimental Measurements of Hot Water Stratification in a Heat Storage Tank in Laboratory Conditions

2019 ◽  
Vol 63 (4) ◽  
pp. 301-307
Author(s):  
Milan Krafčík ◽  
Jana Peráčková
Keyword(s):  
Storage Tank ◽  
Thermal Stratification ◽  
Heat Storage ◽  
Water Storage ◽  
Volume Flow ◽  
Heat Energy ◽  
Hot Water ◽  
Experimental Measurements ◽  
Flow Rates ◽  
Water Stratification

The paper focuses on the experimental measurement of the accumulation of hot water storage with its thermal stratificational thermal layers by means created of elementary conical elements. The basic principle of these elements is the automatic distribution of water temperatures according to temperature and volume flow for a specified time of storage of heat energy. This process involves maintaining the thermal stratification at different height levels of the storage tank, which minimizes the process of balancing the hot water. The aim of the experiments was to demonstrate the thermal energy layering in the 1050 l water storage accumulator in 1 hour depending on the different water flow rates from 250 to 1000 l/h from the heat source.

scholarly journals The impact of inflow velocity on thermal stratification in a water storage tank

2018 ◽  
Vol 44 ◽  
pp. 00079 ◽  
Author(s):  
Kamila Kozłowska ◽  
Piotr Jadwiszczak
Keyword(s):  
Storage Tank ◽  
Thermal Stratification ◽  
Heat Storage ◽  
Three Dimensional ◽  
Hot Water ◽  
Thermal Processes ◽  
Water Storage Tank ◽  
Thermal Mixing ◽  
Computational Fluid Dynamics Cfd ◽  
The Impact

The paper presents the analysis of thermal processes occurring in thermal energy storage tanks used for heating hot water systems. Three-dimensional Computational Fluid Dynamics (CFD) methods were used. The standard buffer charging stage was modelled for three tank inlets’ diameters DN20, DN40 and DN80. With a constant charging water flow and temperature the port diameter affects inlet velocity, heat storage dynamics, thermal stratification and thermocline thickness in storage tank. The smallest diameter causes unfavourable thermal mixing of accumulated water, and the largest diameter supports thermal stratification

Failure analysis of electric-heater tube for heat-storage tank

2018 ◽  
Vol 87 ◽  
pp. 69-79 ◽  
Author(s):  
Sol-Ji Song ◽  
Sangwon Cho ◽  
Woo-Cheol Kim ◽  
Jung-Gu Kim
Keyword(s):  
Failure Analysis ◽  
Storage Tank ◽  
Heat Storage ◽  
Electric Heater ◽  
Heater Tube

Contribution to mathematical modelling of charging and discharging of the seasonal heat storage tank

2012 ◽  
Vol 3 (1) ◽  
pp. 75-79
Author(s):  
L. Böszörményi ◽  
E. Šiváková
Keyword(s):  
Storage Tank ◽  
Heat Supply ◽  
Heat Storage ◽  
Adverse Impact ◽  
Heating Period ◽  
Short Term ◽  
Solar Systems ◽  
Accumulation Capacity ◽  
Seasonal Heat ◽  
Direct Use

Abstract The seasonal heat storage tank is the most important component of the SDH system, which allows significant increase in the share of solar energy in heat supply in comparison with conventional solar systems with short-term accumulation of heat. The adverse impact of their investment sophistication on competitiveness may be compensated by the increased use. For example: Administrative cooperation with heat pump allows increasing the accumulation capacity of the seasonal heat storage tank. Such cooperetion causes the direct use of heating energy and the accumulation of cooling energy produced by heat punp in the final stage of the heating period. It can be used to remote cooling supplied buildings. Experimentation on mathematical models is possible to obtain valuable insights about the dynamics of the processes of charging and discharging in the seasonal storage tank and subsequently used in the design, implementation and operation.

Experimental Evaluation of the Thermal Behavior of a Vertical Solar Tank Using Energy and Exergy Analysis

2005 ◽  
Author(s):  
Ali A. Dehghan ◽  
Mohammad H. Hosni ◽  
S. Hoda Shiryazdi
Keyword(s):  
Temperature Distribution ◽  
Flow Rate ◽  
Storage Tank ◽  
Thermal Stratification ◽  
Exergy Analysis ◽  
Hot Water ◽  
Second Law ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Hot Water Supply

The thermal performance of a Thermosyphon Domestic Solar Water Heater (DSWH) with a vertical storage tank is investigated experimentally. The system is installed on a roof - top of a four person family house and its thermal characteristics is evaluated by means of carefully measuring the temperature distribution of water inside the storage tank, solar collector flow rate and its inlet and outlet temperatures as well as load/consumption outlet and inlet temperatures and the corresponding water flow rate under a realistic operating conditions. The measurements are conducted every hour starting from morning until late night on a daily basis and continued for about 120 days during August until November 2004. It is seen that thermal stratification is well established inside the tank from 11 AM until 10 PM especially during August to September enabling the tank to provide the necessary amount of hot water at an acceptable temperature. However, thermal stratification is observed to start degrading from mid-night until morning when there is no hot water supply from the collector and due to the diffusion of heat from the top hot water layers to the bottom cold region and conduction through tank’s wall. The thermal behavior of the storage tank is also assessed based on both energy and exergy analysis and its first and second law efficiencies are calculated. It is observed that the storage tank under study has an average first law efficiency of 47.8% and is able to supply the required amount of hot water at a proper temperature. The average second law efficiency of the storage tank is observed to be 28.7% and, although is less than its first low efficiency, but is high enough to ensure that the quality of the hot water supply is well preserved. The proper level of second law efficiency is due to the preservation of the thermal stratification inside the storage tank, leading to supply of hot water at highest possible temperature and hence highest possible energy potential. Experiments are also done for no-load conditions when the storage tank only interacts with the collector, without hot water withdrawal from the tank. It is seen that for no-load condition, thermal stratification continuously develops from morning until around 16 PM after which no noticeable changes in the temperature distribution inside the tank is observed.

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