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Title: Frost sensor for use in defrost controls for refrigeration

Abstract

An apparatus and method for measuring the total thermal resistance to heat flow from the air to the evaporative cooler fins of a refrigeration system. The apparatus is a frost sensor that measures the reduction in heat flow due to the added thermal resistance of ice (reduced conduction) as well as the reduction in heat flow due to the blockage of airflow (reduced convection) from excessive ice formation. The sensor triggers a defrost cycle when needed, instead of on a timed interval. The invention is also a method for control of frost in a system that transfers heat from air to a refrigerant along a thermal path. The method involves measuring the thermal conductivity of the thermal path from the air to the refrigerant, recognizing a reduction in thermal conductivity due to the thermal insulation effect of the frost and due to the loss of airflow from excessive ice formation; and controlling the defrosting of the system.

Inventors:
 [1];  [1];  [1];  [1]
  1. ADA Technologies, Inc. 8100 Shaffer Pkwy., Suite 130, Littleton, CO 80127-4107
Issue Date:
Research Org.:
ADA Technologies, Inc., Englewood, CO
OSTI Identifier:
874815
Patent Number(s):
6467282
Assignee:
French; Patrick D. (ADA Technologies, Inc. 8100 Shaffer Pkwy., Suite 130, Littleton, CO 80127-4107); Butz; James R. (ADA Technologies, Inc. 8100 Shaffer Pkwy., Suite 130, Littleton, CO 80127-4107); Veatch; Bradley D. (ADA Technologies, Inc. 8100 Shaffer Pkwy., Suite 130, Littleton, CO 80127-4107); O'Connor; Michael W. (ADA Technologies, Inc. 8100 Shaffer Pkwy., Suite 130, Littleton, CO 80127-4107)
Patent Classifications (CPCs):
F - MECHANICAL ENGINEERING F25 - REFRIGERATION OR COOLING F25D - REFRIGERATORS
F - MECHANICAL ENGINEERING F25 - REFRIGERATION OR COOLING F25B - REFRIGERATION MACHINES, PLANTS OR SYSTEMS
DOE Contract Number:  
FG03-97ER82309
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
frost; sensor; defrost; controls; refrigeration; apparatus; method; measuring; total; thermal; resistance; heat; flow; air; evaporative; cooler; fins; measures; reduction; due; added; ice; reduced; conduction; blockage; airflow; convection; excessive; formation; triggers; cycle; timed; interval; control; transfers; refrigerant; path; involves; conductivity; recognizing; insulation; effect; loss; controlling; defrosting; thermal conductivity; thermal resistance; /62/

Citation Formats

French, Patrick D, Butz, James R, Veatch, Bradley D, and O'Connor, Michael W. Frost sensor for use in defrost controls for refrigeration. United States: N. p., 2002. Web.
French, Patrick D, Butz, James R, Veatch, Bradley D, & O'Connor, Michael W. Frost sensor for use in defrost controls for refrigeration. United States.
French, Patrick D, Butz, James R, Veatch, Bradley D, and O'Connor, Michael W. Tue . "Frost sensor for use in defrost controls for refrigeration". United States. https://www.osti.gov/servlets/purl/874815.
@article{osti_874815,
title = {Frost sensor for use in defrost controls for refrigeration},
author = {French, Patrick D and Butz, James R and Veatch, Bradley D and O'Connor, Michael W},
abstractNote = {An apparatus and method for measuring the total thermal resistance to heat flow from the air to the evaporative cooler fins of a refrigeration system. The apparatus is a frost sensor that measures the reduction in heat flow due to the added thermal resistance of ice (reduced conduction) as well as the reduction in heat flow due to the blockage of airflow (reduced convection) from excessive ice formation. The sensor triggers a defrost cycle when needed, instead of on a timed interval. The invention is also a method for control of frost in a system that transfers heat from air to a refrigerant along a thermal path. The method involves measuring the thermal conductivity of the thermal path from the air to the refrigerant, recognizing a reduction in thermal conductivity due to the thermal insulation effect of the frost and due to the loss of airflow from excessive ice formation; and controlling the defrosting of the system.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2002},
month = {1}
}

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Works referenced in this record:

Fiber optic ice sensors for refrigerators
conference, August 1991