scholarly journals A case study in the field of sustainability energy: Transient heat transfer analysis of an ice thermal storage system with boiling heat transfer process for air-conditioning application

2022 ◽  
Vol 8 ◽  
pp. 1034-1045
Author(s):  
Nidal H. Abu-Hamdeh ◽  
Elias M. Salilih
2013 ◽  
Vol 838-841 ◽  
pp. 1939-1943
Author(s):  
Zhi Yong Li ◽  
Zheng Yong Wang ◽  
Qu Fan ◽  
Zhan Wu

Due to phase change materials (PCMs) composition, machining error, measuring error and other factors, the PCMs thermal physical properties, geometric properties, etc are usually uncertain. As a result, phase change heat transfer process is an uncertainty heat transfer process. But at present, heat transfer characteristics research on phase change thermal storage are all based on certainty heat transfer models (Taken uncertainty factors as certainty factors). In this paper, it is considered factors uncertainty influencing phase change thermal storage heat transfer process. By looked on the variation scope of influence factors as "interval number", based on interval mathematics, perturbation method and finite difference method, "interval number" heat transfer model of phase change thermal storage is established. In this model, the uncertainty variables are decomposed into the sum of the nominal value and the deviation value. PCM uncertainty temperature field can be determined by calculated nominal value and the deviation value of PCM temperature field separately. Comparison between simulation results of the model and experimental data implies that it is necessary to consider influencing factors uncertainty in phase change thermal storage heat transfer analysis.


2013 ◽  
Vol 291-294 ◽  
pp. 632-635
Author(s):  
Zhi Yong Li ◽  
Yu Qing Zhao ◽  
Xue Zou

Because of phase change materials (PCMs)’ composition, machining error, measuring error and other factors, the PCMs’ thermal physical properties, geometric properties, etc are usually uncertain. Phase change heat transfer process is an uncertainty heat transfer process. In this paper, it is considered factors’ uncertainty influencing phase change thermal storage heat transfer process. Heat transfer model of phase change thermal storage is established. And the uncertainty phase change heat transfer process is analysis based on Monte Carlo method. The experiment shows that the temperature of PCMs varied between the upper bound and lower bound of calculations. Comparison between simulation results of the model and experimental data implies that it is necessary to consider influencing factor’s uncertainty in phase change thermal storage heat transfer analysis.


Author(s):  
Daxi Xiong ◽  
Tian Tian ◽  
Victor Wong

In diesel engines, transient heat transfer in the piston/rings/liner system greatly affects the performance of the engine, such as in carbon deposit buildup, microwelding, lubricant degradation, and changing mechanical properties of the materials. The current work aims at studying the local piston/rings/liner transient heat-transfer process by incorporating real time dynamics of the rings in sufficient detail. In the present study, several techniques have been adopted to simulate the transient heat transfer process, with fully-incorporated ring dynamics. These techniques include using the model/submodel approach, local refined mesh approach, and the virtual thermal conductivity approach. The transient temperature and heat flux profiles in the piston and rings are illustrated. The results show that the relative movement of the rings greatly affects the temperature/heat flux distribution and the peak temperature in the top ring. The friction heating between the top ring and the liner is also evaluated. The analysis demonstrates that under some extreme conditions when frictional heating reaches its peak value, some heat flux directs back to enter the ring.


Author(s):  
Qingtai Xiao ◽  
Wen Luo ◽  
Junwei Huang ◽  
Jianxin Xu ◽  
Hua Wang

By bringing two immiscible fluids at different temperatures into a direct contact heat exchanger (DCHE), bubble swarms are produced in the dual-loop ORC direct contact boiling heat transfer process. The aim of this paper is to make effort to explore the interplay between mixing state quality and heat transfer performance of fluids in the DCHE. Through flow visualization of this mixing process, a simple image analysis technique is introduced to represent the formation and evolution of vapor around the injected coolant droplets. Description of the boiling heat transfer process is here achieved by average volumetric heat transfer coefficient (VHTC). Experimental results attest that the proposed mixing index is powerful and sufficient compared with the Betti numbers method for the mixing quality quantification of bubbles inside DCHE. The synergistic association between the fluids mixing process and the heat transfer process is investigated by statistical regression model of new mixing index and VHTC. The contributions, including the data from monitoring practice in ORC heat transfer system and the proposed way, are presented to delve into the transient behaviors comparison of various fluids mixing and heat transfer processes conveniently.


1971 ◽  
Vol 93 (4) ◽  
pp. 408-412 ◽  
Author(s):  
W. C. Peterson ◽  
M. G. Zaalouk

Feedback has been introduced around a boiling heat-transfer process in such a way that stable operation of the process has been obtained in all boiling regions including the transition region, in which, as is well known, the process itself is unstable. This system makes it possible to obtain much new information concerning both the steady-state and dynamic characteristics of boiling heat-transfer processes. Pool-boiling data which were obtained by the use of this system are presented. Accurate measurements of heater voltage and current were obtained by a new technique involving the use of digital instruments. These data are presented in the form of plotted experimental points in the nucleate, transition, and film boiling regions. The new measurement technique is described. Values of n in the equation q/As = CTdn are determined for all three boiling regions, where q = Btu/hr, As is heater surface area, and Td is temperature difference between heater surface and ambient liquid. The ambient liquid is distilled water maintained at saturation temperature under atmospheric pressure.


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