Heat Transfer Characteristics and Efficient Utilization on Ice-Water Cold Storage

1992 Fiscal Year Final Research Report Summary

• Project/Area Number: 03650176
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: Thermal engineering
• Research Institution: Nagaoka University of Technology
• Principal Investigator: HATTORI Masaru Nagaoka University of Technology Department of Mechanical Engineering Professor, 工学部, 教授 (70016426)
• Co-Investigator(Kenkyū-buntansha): YAMADA Shuichi Nagaoka University of Technology Department of Mechanical Engineering Technician, 工学部, 技官 ; AOKI Kazuo Nagaoka University of Technology Department of Mechanical Engineering Associate, 工学部, 助教授 (60115095)
• Project Period (FY): 1991 – 1992
• Keywords: Latent heat cold storage / Free convection / Freezing on vertical wall / Melting of vertical ice wall / forced convection / melting of ice cylinder

Research Abstract

The latent heat cold storage utilizing ice-water system has heat storage capacity of several times as high as sensible heat cold storage using water without freezing. For effective operating ice-water cold storage, it is necessary to clear the properties of heat transfer with freezing and melting. In this report, the freezing and melting of ice on the simple geometrical shaped cooling surfaces which are the fundamentals to give better understanding the heat input and output characteristics of the latent heat cold storage.
Under the free convection, heat transfer characteristics on freezing and melting of ice on vertical wall were investigated by numerical analysis with applying the boundary fitting method. The numerical simulations were made on both freezing and melting under several temperature conditions, and following matters were clarified.
Under free convection, reversing flow of water make badly contributions to heat transfer rate. Because of lower heat transfer rate on ice water interface, freezing rate can roughly be estimated by the solution of usual Stefan Problem. In the melting process, heat transfer coefficient on the heating surface thoroughly depends on the surface temperature. When the surface temperature is kept at 8 degree Celsius, two circulation flows which are the nearly same strength and have mutually opposite flow directions occur and the lowest heat transfer coefficient is observed.
Under forced convection, heat transfer characteristics on melting of a horizontal ice cylinder were studied experimentally. The experiences were done on both ice of fresh water and ice of sodium carbonate aqueous solution of eutectic concentration. The results of melting rate are presented for free stream velocity range 0.008 to 0.056 m/s and fluid temperatures of 1.4 to 8 degree Celsius and -0.7 to 4.6 degree Celsius for aqueous solution of sodium carbonate. The simple relation between the heat transfer rates and free stream velocities are also given.