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Title: Development of a single-phase thermosiphon for cold collection and storage of radiative cooling

Abstract

A single-phase thermosiphon is developed for cold collection and storage of radiative cooling. Compared to the conventional nocturnal radiative cooling systems that use an electric pump to drive the heat transfer fluid, the proposed single-phase thermosiphon uses the buoyancy force to drive heat transfer fluid. This solution does not require electricity, therefore improving the net gain of the radiative cooling system. A single-phase thermosiphon was built, which consists of a flat panel, a cold collection tank, a water return tube, and a water distribution tank. Considering that outdoor radiative cooling flux is constantly changing (i.e. uncontrollable), an indoor testing facility was developed to provide a controllable cooling flux (comparable to a radiative cooling flux of 100 W/m2) for the evaluation of thermosiphon performance. The testing apparatus is a chilled aluminum flat plate that has a controlled air gap separation relative to the flat panel surface of the thermosiphon to emulate radiative cooling. With an average of 105 W/m2 cooling flux, the 18 liters of water in the thermosiphon was cooled to an average temperature of 12.5 degrees C from an initial temperature of 22.2 degrees C in 2 h, with a cold collection efficiency of 96.8%. The results obtained havemore » demonstrated the feasibility of using a single-phase thermosiphon for cold collection and storage of radiative cooling. Additionally, the effects of the thermosiphon operation conditions, such as tilt angle of the flat panel, initial water temperature, and cooling energy flux, on the performance have been experimentally investigated. Modular design of the single-phase thermosiphon gives flexibility for its scalability. A radiative cooling system with multiple thermosiphon modules is expected to play an important role in cooling buildings and power plant condensers.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
U.S. Department of Energy, Advanced Research Projects Agency-Energy (ARPA-E)
OSTI Identifier:
1394905
Report Number(s):
NREL/JA-5500-70195
Journal ID: ISSN 0306-2619
DOE Contract Number:
AC36-08GO28308
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Energy; Journal Volume: 205; Journal Issue: C
Country of Publication:
United States
Language:
English
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; single-phase thermosiphon; radiative cooling; natural convection; cold collection; cold storage

Citation Formats

Zhao, Dongliang, Martini, Christine Elizabeth, Jiang, Siyu, Ma, Yaoguang, Zhai, Yao, Tan, Gang, Yin, Xiaobo, and Yang, Ronggui. Development of a single-phase thermosiphon for cold collection and storage of radiative cooling. United States: N. p., 2017. Web. doi:10.1016/j.apenergy.2017.08.057.
Zhao, Dongliang, Martini, Christine Elizabeth, Jiang, Siyu, Ma, Yaoguang, Zhai, Yao, Tan, Gang, Yin, Xiaobo, & Yang, Ronggui. Development of a single-phase thermosiphon for cold collection and storage of radiative cooling. United States. doi:10.1016/j.apenergy.2017.08.057.
Zhao, Dongliang, Martini, Christine Elizabeth, Jiang, Siyu, Ma, Yaoguang, Zhai, Yao, Tan, Gang, Yin, Xiaobo, and Yang, Ronggui. Wed . "Development of a single-phase thermosiphon for cold collection and storage of radiative cooling". United States. doi:10.1016/j.apenergy.2017.08.057.
@article{osti_1394905,
title = {Development of a single-phase thermosiphon for cold collection and storage of radiative cooling},
author = {Zhao, Dongliang and Martini, Christine Elizabeth and Jiang, Siyu and Ma, Yaoguang and Zhai, Yao and Tan, Gang and Yin, Xiaobo and Yang, Ronggui},
abstractNote = {A single-phase thermosiphon is developed for cold collection and storage of radiative cooling. Compared to the conventional nocturnal radiative cooling systems that use an electric pump to drive the heat transfer fluid, the proposed single-phase thermosiphon uses the buoyancy force to drive heat transfer fluid. This solution does not require electricity, therefore improving the net gain of the radiative cooling system. A single-phase thermosiphon was built, which consists of a flat panel, a cold collection tank, a water return tube, and a water distribution tank. Considering that outdoor radiative cooling flux is constantly changing (i.e. uncontrollable), an indoor testing facility was developed to provide a controllable cooling flux (comparable to a radiative cooling flux of 100 W/m2) for the evaluation of thermosiphon performance. The testing apparatus is a chilled aluminum flat plate that has a controlled air gap separation relative to the flat panel surface of the thermosiphon to emulate radiative cooling. With an average of 105 W/m2 cooling flux, the 18 liters of water in the thermosiphon was cooled to an average temperature of 12.5 degrees C from an initial temperature of 22.2 degrees C in 2 h, with a cold collection efficiency of 96.8%. The results obtained have demonstrated the feasibility of using a single-phase thermosiphon for cold collection and storage of radiative cooling. Additionally, the effects of the thermosiphon operation conditions, such as tilt angle of the flat panel, initial water temperature, and cooling energy flux, on the performance have been experimentally investigated. Modular design of the single-phase thermosiphon gives flexibility for its scalability. A radiative cooling system with multiple thermosiphon modules is expected to play an important role in cooling buildings and power plant condensers.},
doi = {10.1016/j.apenergy.2017.08.057},
journal = {Applied Energy},
number = C,
volume = 205,
place = {United States},
year = {Wed Nov 01 00:00:00 EDT 2017},
month = {Wed Nov 01 00:00:00 EDT 2017}
}