scholarly journals Mathematics Modelling and Performance Analysis of the Heat Transfer on Vacuum Tube Collector of Water Heater Application

2020 ◽  
Vol 190 ◽  
pp. 00022
Author(s):  
Lia Hamanda ◽  
Gunawan Nugroho

The aim of this work is to study a mathematical modelling and simulation for predicting the thermal performance heat-pipe evacuated a solar collector for water heater, which was considered the temperature distribution along the tube axis and radius. This model used to help in studying the dynamic behaviour of the system design and the effect of influential parameter on the water heater process. The result showed that water heating is affected by the surface of collector, metrological conditions such as solar radiation and outdoor temperature, even the thermal performance of the collector.

The Fin act as dissipiating elements, selection of proper geometry plays crusial role in increasing the rate of heat transfer and performance of the system. This work has been undertaken to investigate and compare thermal performance of solid and hollow pin-fin. Heat transfer analysis of solid and hollow pin fin carried and the results was compared with the experimental results. experiment was conducted to analyze the natural convection around solid hollow pin fin, and compare thermal performance of hollow pin fin with the solid pin fin of same dimension and orientation. The experimental result of temperature distribution shows that the faster temperature drop along the length. The high value of convective heat transfer in the initial phase due to which faster temperature drop takes place. Convection is found to be dominating due to less area for conduction along the length. Theoretical value and experimental value are close to each for temperature distribution as well the convective heat transfer coefficient. Efficiency is reduced in the case of hollow fin but the effectiveness of the hollow pin fin is increased by 1.76 times from an economical point of view, holoow pin fin is more efficient solution.


Processes ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 756 ◽  
Author(s):  
Nurril Ikmal Shamsul Azha ◽  
Hilmi Hussin ◽  
Mohammad Shakir Nasif ◽  
Tanweer Hussain

Various studies to improve the thermal performance of flat plate solar collector (FPSC) solar water heater have been conducted, and more are currently in progress. This study aims to review existing methods on thermal performance enhancement for FPSC and discuss on heat-transfer enhancement using vibration and its potential application for FPSC. Ten methods for improving thermal performance are identified, which include applications of nanofluids, absorber coatings, phase change materials (PCM), thermal performance enhancers, FPSC design modifications, polymer materials, heat loss reduction, mini and micro channel and heat-transfer enhancement using vibration. An examination of heat-transfer enhancement using vibration in low frequency ranges for an evacuated-tube solar collector (ETSC) solar water heater system showed that it can potentially achieve heat-transfer enhancement of up to 78%. Nevertheless, there is still a lack of research on the applications of heat-transfer enhancement using vibration on FPSC to date.


Author(s):  
Yuhiro Iwamoto ◽  
Hiroshi Yamaguchi

For supercritical CO2, a small change in temperature or pressure can result in large change in density, especially in the state close to the critical point. The large change in density can easily induce the natural convective flow. In this chapter, a solar water heater using supercritical CO2 which is originally designed and constructed will be introduced. The solar water heater is a closed loop system with main components of an evacuated solar collector and a heat exchanger. The working fluid of CO2 is naturally driven by the large change in density with absorbing and transporting heat in the solar collector. And the heat energy (hot water) is produced by exchanging the transferred heat with water in the heat exchanger. This chapter will describe the typical system operation and performance at different season and climates.


2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Djamel Benmenine ◽  
Mokhtar Ghodbane

This study aims to conduct an experimental thermal examination of a parabolic trough collector in Ouargla region at Algeria, which will be used as a solar water heater. The solar collector was manufactured and then experimentally tested, as its theoretical optical performance was estimated at 75.06%, while the values of its true thermal performance are 10.61, 10.68 and 8.85 % for 13 May, 14 May and 15 May. Although its thermal performance is somewhat low, the studied PTC is effective in heating the water, whereas, using a volumetric flow of 0.011 l/s, about 317 liters of water can be heated daily at 42°C, knowing that the daily average consumption of hot water in a typical house is 250 liters because the Ouargla region is strategically located that receives huge amounts of solar irradiance


Author(s):  
Son H. Ho ◽  
Muhammad M. Rahman ◽  
Aydin K. Sunol

This paper presents a numerical modeling and simulation of heat transfer in a food self-heating unit for group meals. A model of a water-activated heater based on an exothermic reaction was developed. The resulting governing equations of heat conduction and chemical reaction were solved for an analytical approximate solution, to which experimental data found from literature were compared and curve fitted. Then a model of a complete food-heating unit, which includes a stack of four sets of food tray, heating tray, and heater sandwiched between them, as well as the cardboard container, was developed. A system of governing equations for heat transfer in the composite medium for the complete model was solved. Numerical solution of temperature distribution within the food-heating unit is presented. The responses in thermal performance of the heating system to the parameters that influence heating profiles of the heater such as decay constant and heat generation were studied in order to improve the thermal performance of the heating system. The results are useful for designing and optimizing self-heating systems for food served to groups of many people.


2014 ◽  
Vol 624 ◽  
pp. 332-338 ◽  
Author(s):  
Shouquat Hossain ◽  
Ali Wadi Abbas ◽  
Jeyraj Selvaraj ◽  
Ferdous Ahmed ◽  
Nasrudin Bin Abd Rahim

An investigation is reported of the thermal performance of a flat plate solar water heater with a circulating absorber pipe surface. The thermal performance of the 2-side parallel serpentine flow solar water heater depends significantly on the heat transfer rate between the absorber surface and the water, and on the amount of solar radiation incident on the absorber surface. The modified pipe arrangement has a higher characteristic length for convective heat transfer from the absorber to the water, in addition to having more surface area exposed to solar radiation. It means during the operation of water heater, more solar energy is converted into useful heat. However, this modification has reduced the efficiency of the system marginally.


Author(s):  
Zhongyang Shen ◽  
Qi Jing ◽  
Yonghui Xie ◽  
Di Zhang

Cooling technique in mini-scale heat sink is essential with the development of high power electronics such as electronic chip. As heat transfer techniques, jet impingement cooling and convective cooling by roughened surface are commonly adopted. To obtain good cooling efficiency, the cooling structure within the heat sink should be carefully designed. In the present study, mini-scale heat sink with feature size of 1∼10 mm is set up. Arrangement of jet impingement and dimple/protrusion surface are designed as heat transfer augmentation approaches. The effect of dimple/protrusion configuration is discussed. From the result, the Nu distribution of on heat sink surface is demonstrated for each case. The pressure penalty due to the arrangement of roughened structure is evaluated. Also, thermal performance TP and performance evaluation plot are adopted as evaluations of cooling performance for each configuration. Comparing all cases, optimal cooling structure considering the energy saving performance is obtained for the mini-scale heat sink. Referencing the statistics, new insight has been provided for the design of cooling structure inside mini-scale heat sink.


2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Tao Zhang ◽  
Gang Pei ◽  
Qunzhi Zhu ◽  
Jie Ji

Volume-filling ratio of the working fluid has a predominant effect on the system performance of a closed two-phase solar water-heating (SWH) system. To study this effect, a prototype of a loop thermosyphon SWH system, which uses remolded flat-plate solar collector as the evaporator and the coil pipe in the water tank as the condenser, was set up. A set of long-term outdoor experiments under 10%, 20%, 30%, 50%, and 70% volume-filling ratios were conducted in this paper. R600a was used as working fluid. Loop thermosyphon solar collector thermal performance and system thermal performance under different volume-filling ratios, including the temperature distribution of loop thermosyphon evaporator, were presented. It is shown that the loop thermosyphon solar collector and the system had a better thermal performance than the conventional ones under 30% and 50% volume-filling ratio, and the loop thermosyphon evaporator had an even temperature distribution when the volume-filling ratio was higher than 30%. The optimum volume filing ratio lies in between 30% and 50% of the whole system volume.


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