Abstract
Quantitative and visual data on defrost are presented. The data base comprises normal and in plane images of the defrost process over a range of ambient temperature, dew point, and surface temperature. Twelve frost layers are created at prescribed surface temperature, dew point, and ambient temperature. Melting is initiated by application of heating on the frosted surface. Predictions of the multistage defrost model developed in Chap. 3 are compared to the reduced data where possible, and empirically based relations for heat and mass transfer are developed. Assumptions used to simplify the differential equations for coupled heat and mass transfer in Chap. 3 are validated by the measurements. Overall defrost efficiency is proportional to initial frost thickness.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsAbbreviations
- A:
-
Area (m2)
- c:
-
Specific heat (J/kg K)
- E:
-
Energy stored (J)
- f:
-
Wetted area fraction, Aw/As
- h:
-
Heat transfer coefficient (W/m2 K)
- h*:
-
Total heat transfer coefficient (5.11)
- hm :
-
Mass transfer coefficient (m/s)
- Le1 :
-
Lewis number for Stage I (3.39)
- Le2f :
-
Lewis number for frost in Stage II (3.61)
- Le2v :
-
Lewis number for vapor in State II (3.61)
- m:
-
Mass (kg)
- m″:
-
Mass flux (kg/m2 s)
- Q:
-
Heat transfer (W)
- q″:
-
Heat flux (W/m2)
- St1 :
-
Stephan number for Stage I (3.39)
- St2v :
-
Stephan number for vapor in State II (3.61)
- t:
-
Time (s)
- T:
-
Temperature (K)
- δ:
-
Frost thickness (m)
- ε:
-
Porosity (–)
- λfg :
-
Latent heat of vaporization (J/kg)
- λif :
-
Latent heat of fusion (J/kg)
- Γ1 :
-
(St1Le1)−1
- Γ2 :
-
(St2vLe2v)−1
- ρ:
-
Density (kg m3)
- 0:
-
Initial time
- 1,2,3:
-
Denotes defrost stage
- ch:
-
Chamber
- d:
-
Defrost
- dp:
-
Dew point
- f:
-
Frost
- fg:
-
Evaporation
- i:
-
Ice
- lt:
-
Latent
- m:
-
Melt
- s:
-
Surface
- sn:
-
Sensible
- ts:
-
Test surface
- v:
-
Vapor
- w:
-
Water, wetted
References
Donnellan W (2007) Investigation and optimization of demand defrost strategies for transport refrigeration systems. Doctoral dissertation, Galway-Mayo Institute of Technology, Galway
Janssen DD (2011) Experimental strategies for frost analysis. Master’s thesis, University of Minnesota, Minneapolis
Janssen DD, Mohs WF, Kulacki FA (2012a) Modeling frost growth—a physical approach. In: Proceedings of the 2012 ASME summer heat transfer conference, paper no. HT2012-58054
Janssen DD, Mohs WF, Kulacki FA (2012b) High resolution imaging of frost melting. In: Proceedings of the 2012 ASME summer heat transfer conference, paper no. HT2012-58061
Lee YB, Ro ST (2002) Frost formation on a vertical plate in simultaneously developing flow. Exp Therm Fluid Sci 26:939–945
Mohs WF (2013) Heat and mass transfer during the melting process of a porous frost layer on a vertical surface. Doctoral dissertation, Universality of Minnesota, Minneapolis
Muehlbauer J (2006) Investigation of performance degradation of evaporators for low temperature refrigeration applications. Master’s thesis, University of Maryland, College Park
Na B (2003) Analysis of frost formation in an evaporator. Doctoral dissertation, Pennsylvania State University, University Park
Author information
Authors and Affiliations
Rights and permissions
Copyright information
© 2015 Springer International Publishing Switzerland
About this chapter
Cite this chapter
Mohs, W.F., Kulacki, F.A. (2015). Measurement of the Defrost Process. In: Heat and Mass Transfer in the Melting of Frost. SpringerBriefs in Applied Sciences and Technology(). Springer, Cham. https://doi.org/10.1007/978-3-319-20508-3_5
Download citation
DOI: https://doi.org/10.1007/978-3-319-20508-3_5
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-20507-6
Online ISBN: 978-3-319-20508-3
eBook Packages: EngineeringEngineering (R0)