A transient analysis of frost formation on a parallel plate evaporator
- Univ. of Guanajuato (Mexico). Dept. of Mechanical Engineering
This paper presents the development of a transient model for evaluating frost formation on a parallel plate evaporator for heat pump applications. The model treats the frost layer as a porous substance, and applies the equations of conservation of mass, momentum and energy to calculate the growth and densification of the frost layer. Empirical correlations for thermal conductivity and tortuosity as a function of density are incorporated from previous studies. Frost growth is calculated as a function of time, Reynolds number, longitudinal location, plate temperature, and ambient air temperature and humidity. The main assumptions are: ideal gas behavior for air and water vapor, uniform frost density and thermal conductivity across the thickness of the frost layer; and quasi-steady conditions during the whole process. The mathematical model is validated by comparing the predicted values of frost thickness and frost density with results obtained in recent experimental studies. A good agreement was obtained in the comparison. The frost formation model calculates pressure drop and heat transfer resistance that result from the existence of the frost layer, and it can therefore be incorporated into a heat pump model to evaluate performance losses due to frosting as a function of weather conditions and time of operation since the last evaporator defrost.
- OSTI ID:
- 483919
- Report Number(s):
- CONF-961105-; ISBN 0-7918-1527-7; TRN: IM9726%%312
- Resource Relation:
- Conference: 1996 international mechanical engineering congress and exhibition, Atlanta, GA (United States), 17-22 Nov 1996; Other Information: PBD: 1996; Related Information: Is Part Of Proceedings of the ASME Advanced Energy Systems Division. AES-Volume 36; Bittle, R.R. [ed.] [Texas Christian Univ., Fort Worth, TX (United States)]; Duncan, A.B. [ed.] [Marquette Univ., Milwaukee, WI (United States)]; Fiszdon, J. [ed.] [Mankato State Univ., MN (United States)]; Garimella, S. [ed.] [Western Michigan Univ., Kalamazoo, MI (United States)]; Herold, K. [ed.] [Univ. of Maryland, College Park, MD (United States)]; Nutter, D.W. [ed.] [Univ. of Arkansas, Fayetteville, AR (United States)]; O`Neal, D. [ed.] [Texas A and M Univ., College Station, TX (United States)]; Shiva Prasad, B.G. [ed.] [Dresser-Rand, Painted Post, NY (United States)]; Den Braven, K. [ed.] [Univ. of Idaho, Moscow, ID (United States). Dept. of Mechanical Engineering]; PB: 550 p.
- Country of Publication:
- United States
- Language:
- English
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