Effects of Tube Space on the Thermal Performance of Water-in-Glass Evacuated Tube Solar Water Heaters

2013 ◽  
Vol 860-863 ◽  
pp. 81-87
Author(s):  
Yu Qin Yang ◽  
Run Sheng Tang
Keyword(s):  
Thermal Performance ◽  
Theoretical Calculations ◽  
Technical Specification ◽  
Water Heater ◽  
Solar Water ◽  
Water Heaters ◽  
Solar Water Heaters ◽  
Evacuated Tube ◽  
Tube Space ◽  
Tube Distance

In the present specification of domestic solar water heating systems (GB/T19141), regardless of the type of collectors used in the systems, Q17, the daily heat gain corresponding to the daily radiation of 17MJ/m2 on the collector surface, is a key indication to rate the thermal performance of a domestic solar water heaters. In this work, an attempt was made to investigate effect of the distance between two adjacent tubes in solar tube collectors of a water-in-glass evacuated tube solar water heater (ETSWH) on by theoretical calculations and experimental measurements. Results obtained by simulations and experimental test showed that the tube space had a significant effect on of the ETSWH, the shorter the tube distance, the higher the Q17, thus better the ETSWH performs. However, the actual situation is the case, the shorter the tube distance, the lower the real daily solar gain of the system, thus worse it performs. This implied that Q17 as the indication of thermal performance of the ETSWH is not reasonable, and specifying the tube distance in solar tube collectors of the ETSWH in the technical specification of GB/T19141 is advisable so as to eliminate effect of the tube distance on Q17.

Comparative Study of the Thermal Performance of Two Thermosiphon Solar Water Heaters System

2020 ◽  
Vol 9 (3) ◽  
pp. 401-410
Author(s):  
Blaise Kamenan Koua ◽  
Paul Magloire Ekoun Koffi ◽  
Prosper Gbaha
Keyword(s):  
Thermal Performance ◽  
Weather Conditions ◽  
Glass Wool ◽  
Hot Water ◽  
Experimental Investigations ◽  
Coconut Fiber ◽  
Water Heater ◽  
Solar Water ◽  
Water Heaters ◽  
Solar Water Heaters

 The aim of this study is to present the comparative results of experimental investigations of the thermal performance of two thermosiphon solar water heaters system (SWHS). The first uses the coconut fiber (CF), a local vegetable and the second, the glass wool (GW), an imported and expensive material, as thermal insulations. The maximum instantaneous efficiencies are, respectively, 65.30 % and 58.7% with glass wool and coconut fiber while the mass flow rate values are, respectively, 0.0098 kg/s and 0.0078 kg/s with glass wool and coconut fiber. In addition, the calculated average values of F’(τα) and F’UL are, respectively, 0.79 and 5.86 Wm-2°C for the coconut fiber collector and 0.8 and 5.26 Wm-2°C for the glass wool collector. The average heat exchanger effectiveness obtained for the two SWHS are superior to 50%. As an environment-friendly and renewable material, coconut fiber is particularly suitable for thermal insulation in order to save energy. The experimental results show the ability of the constructed solar water heater in providing hot water suitable for maternity, hotels, households and encourage its implementation and utilization on a broad scale. The SWHS can be used in any weather conditions. ©2020. CBIORE-IJRED. All rights reserved

scholarly journals Assessment and Modeling of Household-Scale Solar Water Heater Application in Zambia: Technical, Environmental, and Energy Analysis

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Mehdi Jahangiri ◽  
Esther T. Akinlabi ◽  
Sam M. Sichilalu
Keyword(s):  
Fossil Fuels ◽  
Hot Water ◽  
Climate Data ◽  
Ghg Emission ◽  
Water Heater ◽  
Ghg Mitigation ◽  
Solar Water ◽  
Water Heaters ◽  
Industrial Sectors ◽  
Solar Water Heaters

Solar water heaters (SWHs) are one of the most effective plans for general and easy use of solar energy to supply hot water in domestic and industrial sectors. This paper gives the first-ever attempts to assess the optimal localization of SWHs across 22 major cities in Zambia, as well as determine the possibility of hot water generation and model the greenhouse gas (GHG) emission saving. The climate data used is extracted by using the MeteoSyn software which is modeled in TSOL™. Results show the high potential of GHG emission reduction due to nonconsumption of fossil fuels owing to the deployment of SWHs, and three cities Kabwe, Chipata, and Mbala had the highest GHG mitigation by 1552.97 kg/y, 1394.8 kg/y, and 1321.39 kg/y, respectively. On average, SWHs provide 62.47% of space heating and 96.05% of the sanitary hot water requirement of consumers. The findings have shown the potential for the deployment of SWHs in Zambia. The techno-enviro study in this paper can be used by the policymakers of Zambia and countries with similar climates.

Thermal Properties Study of a Solar Water Heater Tank with a Mantle Exchanger

2014 ◽  
Vol 3 (1) ◽  
pp. 92-100 ◽  
Author(s):  
Mourad Chikhi ◽  
Rabah Sellami ◽  
Nachida Kasbadji Merzouk
Keyword(s):  
Heat Exchanger ◽  
Renewable Energy Sources ◽  
Supply And Demand ◽  
Research Work ◽  
Solar Water Heater ◽  
Water Heater ◽  
Solar Water ◽  
Incentive Programs ◽  
Water Heaters ◽  
Solar Water Heaters

The development and use of renewable energy sources and technologies are becoming vital for the management of energy supply and demand. For development solar water heaters, the incentive programs are supported by the Algerian government to generalize the using of this kind of energy especially in Sahara. This study is a part of program to develop a new solar water heater in UDES (Algeria). In this research work, the thermal performance of a solar water heater with a mantle heat exchanger is investigated numerically using Comsol Multyphysics software. The objective is to investigate the influence of the mantle heat exchanger thickness on the performance of solar water heaters. The results show, for 160 liters capacity of the solar water heaters tank, the 13mm of the heat exchanger thickness leads to improve the efficiency of the solar water heater.

scholarly journals Thermal efficiency and cost analysis of solar water heater made in Rwanda

2018 ◽  
Vol 37 (3) ◽  
pp. 1147-1161 ◽  
Author(s):  
Esdras Nshimyumuremyi ◽  
Wang Junqi
Keyword(s):  
Cost Analysis ◽  
Thermal Efficiency ◽  
Solar Water Heater ◽  
Water Heating ◽  
Water Heater ◽  
Solar Water Heating ◽  
Solar Water ◽  
Water Heaters ◽  
Solar Water Heaters ◽  
Made In

Solar water heating is a technology of capturing the energy from the sun's radiation for the purpose of raising the temperature of water from water supply temperature to the desired higher temperature depending on the use. There are many views and discussions on the questions of thermal efficiency of solar water heaters and their associated cost, especially different customers/users want to replace their existing conventional water heating energy by solar water heating systems. In this present paper, a deep investigation has been accomplished to determine thermal efficiency and cost analysis of solar water heater made in Rwanda. During manufacturing of solar water heater, the collector was the main part to emphasize on. The high efficiency of the system was achieved by replacing galvanized iron sheet by aluminum sheet slotted and black painted as an absorber plate. The ambient temperature and average solar radiation of the three sites where solar water heaters are installed were investigated. The used materials, specifications and sizing were discussed in this paper.

Characteristic Heat Removal Efficiency for Thermosyphon Solar Water Heaters During the System Application Phase

2004 ◽  
Vol 126 (3) ◽  
pp. 950-956 ◽  
Author(s):  
J. M. Chang
Keyword(s):  
Removal Efficiency ◽  
Empirical Model ◽  
System Application ◽  
Heat Removal ◽  
Solar Water Heater ◽  
Water Heater ◽  
Solar Water ◽  
Water Heaters ◽  
Heat Removal Efficiency ◽  
Solar Water Heaters

The overall performance rating of a thermosyphon solar water heater should take into consideration its heat removal efficiency during the system application phase. This study employs a precise on-line operation to first identify physical heat removal patterns of a thermosyphon solar water heater, and then develops an empirical model for deriving its characteristic heat removal efficiency. This empirical model is in the form of a logarithmic curve, and has a high data correlation coefficient of 0.889 to 0.967. Based upon the empirical model, this study defines a characteristic heat removal efficiency parameter for thermosyphon solar water heaters. Finally, this study establishes a storage tank design method which enables the characteristic heat removal efficiency of the complete system to be optimized.

Numerical Simulation of Evacuated Tube Solar Water Heaters

2012 ◽  
Author(s):  
Michele Pinelli ◽  
Alessio Suman ◽  
Michele Vanti
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Circulation Rate ◽  
Heat Distribution ◽  
Solar Water ◽  
Water Heaters ◽  
Reference Parameters ◽  
Solar Water Heaters ◽  
Evacuated Tube ◽  
Rayleigh Numbers

This paper evaluates the characteristics of water-in-glass evacuated tube solar water heaters including assessment of the circulation rate through single ended tubes. A numerical model of the fluid flow inside a single ended evacuated tube has been developed assuming no interaction between adjacent tubes in the collector array. The numerical model is firstly validated by means of literature data. Then, the performance in terms of circulation mass flow rate in different heat flux condition and at different inclination angle of the collector are evaluated. Moreover, a sensitivity analysis on the effect of the assumptions of different reference parameters and of the choice of the values of the fluid thermophysical properties is carried out and a quantitative analysis of the expected uncertainty is presented. Finally, an extension of previous literature correlations in terms of non-dimensional Reynolds and Rayleigh numbers is proposed. Regarding heating boundary conditions, the circumferential heat distribution was found to be an important parameter influencing the flow structure and circulation rate through the tube.

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