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Title: Thermal storage in ammonium alum/ammonium nitrate eutectic for solar space heating

Abstract

Ammonium alum and ammonium nitrate in the weight ratio of 1:1 forms a eutectic that melts at 53 C and crystallizes at 48 C. The latent heat of fusion of this eutectic was found to be 215 kJ/kg. Its enthalpy as measured by drop calorimetry was found to be 287 kJ/kg in the temperature range of 24--65 C, which is 1.67 times greater than water (172.2 kJ/kg) and 8.75 times greater than rock (32.8 kJ/kg). Upon several heating/cooling cycles, phase separation was observed. However, by adding 5% attapulgite clay to this eutectic mixture, phase separation was prevented. This eutectic was encapsulated in 0.0254m diameter HDPE hollow balls and subjected to about 1,100 heating/cooling cycles in the temperature range between 25 and 65 C. At the end of these cycles, the decrease in enthalpy was found to be 5%. A scale model of the heat storage unit was fabricated to investigate the heat transfer characteristics of this eutectic encapsulated in HDPE balls. The thermal extraction efficiency of the system was measured with the recirculation of hot air during charging and was found to be in the range of 85--98%.

Authors:
; ; ; ;  [1]
  1. Univ. of Florida, Gainesville, FL (United States). Dept. of Mechanical Engineering
Publication Date:
OSTI Identifier:
109900
Report Number(s):
CONF-950725-
ISBN 0-89553-167-4; TRN: IM9543%%201
Resource Type:
Conference
Resource Relation:
Conference: SOLAR `95: national solar energy conference: 10,000 solutions - paths to a renewable future, Minneapolis, MN (United States), 15-20 Jul 1995; Other Information: PBD: 1995; Related Information: Is Part Of Solar `95: Technical papers. Proceedings of the 1995 annual meeting of the American Solar Energy Society; Campbell-Howe, R.; Wilkins-Crowder, B. [eds.]; PB: 456 p.
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; SOLAR HEATING SYSTEMS; LATENT HEAT STORAGE; EUTECTICS; HEAT TRANSFER; THERMAL ENERGY STORAGE EQUIPMENT

Citation Formats

Goswami, D Y, Jotshi, C K, Klausner, J F, Hsieh, C K, and Srinivasan, N. Thermal storage in ammonium alum/ammonium nitrate eutectic for solar space heating. United States: N. p., 1995. Web.
Goswami, D Y, Jotshi, C K, Klausner, J F, Hsieh, C K, & Srinivasan, N. Thermal storage in ammonium alum/ammonium nitrate eutectic for solar space heating. United States.
Goswami, D Y, Jotshi, C K, Klausner, J F, Hsieh, C K, and Srinivasan, N. 1995. "Thermal storage in ammonium alum/ammonium nitrate eutectic for solar space heating". United States.
@article{osti_109900,
title = {Thermal storage in ammonium alum/ammonium nitrate eutectic for solar space heating},
author = {Goswami, D Y and Jotshi, C K and Klausner, J F and Hsieh, C K and Srinivasan, N},
abstractNote = {Ammonium alum and ammonium nitrate in the weight ratio of 1:1 forms a eutectic that melts at 53 C and crystallizes at 48 C. The latent heat of fusion of this eutectic was found to be 215 kJ/kg. Its enthalpy as measured by drop calorimetry was found to be 287 kJ/kg in the temperature range of 24--65 C, which is 1.67 times greater than water (172.2 kJ/kg) and 8.75 times greater than rock (32.8 kJ/kg). Upon several heating/cooling cycles, phase separation was observed. However, by adding 5% attapulgite clay to this eutectic mixture, phase separation was prevented. This eutectic was encapsulated in 0.0254m diameter HDPE hollow balls and subjected to about 1,100 heating/cooling cycles in the temperature range between 25 and 65 C. At the end of these cycles, the decrease in enthalpy was found to be 5%. A scale model of the heat storage unit was fabricated to investigate the heat transfer characteristics of this eutectic encapsulated in HDPE balls. The thermal extraction efficiency of the system was measured with the recirculation of hot air during charging and was found to be in the range of 85--98%.},
doi = {},
url = {https://www.osti.gov/biblio/109900}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Oct 01 00:00:00 EDT 1995},
month = {Sun Oct 01 00:00:00 EDT 1995}
}

Conference:
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