Li, Ren-fei, Gao, Wen-feng, Lin, Wen-xian, and Liu, Tao (2014) Numerical simulation analysis on the influence of tilt angle on the evacuated tube water heaters. Energy Engineering, 2014 (5). pp. 31-38.

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Abstract

The solar load model of fluent software was used to conduct three-dimensional direct numerical simulations on the domestic solar water heater, and the velocity field and the temperature field with the heat time at tilt angles of 30°, 45°, 60° were obtained. The flow dynamics and heat transfer process of evacuated tube water heater system were analyzed. The results showed that, during the evacuated tube was heated, the top of the evacuated tube wall emerge the maximum temperature, the water temperature of the evacuated tube in the tank under the opening relate to the water temperature above the opening stratification was more obvious, and above the opening of the tank was almost the same, which illustrated that the water above the opening inside the tank mix fully; For the system tilt angle of 30° and 45°, the temperature difference was from 10 K to 30 K between under the opening and above the opening in the tank with the heat time. In the case of 45° tilt angle, when considering the cold water under the opening in the tank, the temperature difference between the evacuated tube and the tank was from 0.73 K to 1.13 K with the heat time, only account for evenly distributed three temperature points inside the central surface of the evacuated tube and the water tank, the temperature difference between the evacuated tube and the tank was from 0.15 K to 0.03 K with the heat time; with the increase of the tilt angle from 30° to 60°, the area under the opening in the tank beceme smaller gradually. In order to reduce the cold water area at the bottom of the tank, the evacuated tube inserted into the tank should be as short as possible.

Item ID:	38341
Item Type:	Article (Research - C1)
ISSN:	1004-3950
Keywords:	domestic evacuated tube solar water heater; tilt angle; flow field and temperature field; numerical simulation
Related URLs:	http://d.wanfangdata.com.cn/periodical_n...
Additional Information:	Original paper is written and published in Chinese.
Funders:	National Natural Science Foundation of China
Date Deposited:	06 May 2015 01:22
FoR Codes:	09 ENGINEERING > 0915 Interdisciplinary Engineering > 091505 Heat and Mass Transfer Operations @ 50% 09 ENGINEERING > 0915 Interdisciplinary Engineering > 091504 Fluidisation and Fluid Mechanics @ 50%
SEO Codes:	85 ENERGY > 8505 Renewable Energy > 850506 Solar-Thermal Energy @ 100%
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