Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Optimization of the defrost cycle of an evaporator

IP.com Disclosure Number: IPCOM000246140D
Publication Date: 2016-May-11
Document File: 3 page(s) / 177K

Publishing Venue

The IP.com Prior Art Database

Abstract

Refrigerators use a significant amount of the total energy in today's households. Devices which contain an automatic defrost system show a high potential to decrease the overall energy consumption by optimizing the timing parameters of the defrost system. This article describes the well-known technique of measuring differential pressure over the evaporator to detect the amount of grown ice and the optimal time to activate the defrost heater. To minimize the energy consumption of the heater, an optimization algorithm based on the differential pressure is introduced.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 51% of the total text.

Page 01 of 3

Optimization of the defrost cycle of an evaporator

Abstract

Refrigerators use a significant amount of the total energy in today's households. Devices which contain an automatic defrost system show a high potential to decrease the overall energy consumption by optimizing the timing parameters of the defrost system. This article describes the well-known technique of measuring differential pressure over the evaporator to detect the amount of grown ice and the optimal time to activate the defrost heater. To minimize the energy consumption of the heater, an optimization algorithm based on the differential pressure is introduced.

Background

Today's refrigerators contain an automatic defrost system which melts grown ice on the evaporator periodically. A fan generates an air circulation and blows cold air, cooled by an evaporator, installed on the backside, into the compartment. Depending on the usage of the refrigerator (number of door openings, amount and kind of food stored, etc…) and ambient conditions (mainly temperature and humidity) more or less humidity condensates on the cold evaporator and freezes to ice (Figure 1). A heater integrated in the evaporator is activated periodically to melt the ice.

Refrigerators use a significant amount of the total energy in today's households. In the context of the energy turnaround and general energy cost reductions, the automatic defrost system has a high potential to optimize the overall energy consumption of a refrigerator. The following two parameters are important to optimize the overall efficiency (Figure 2):

Heater off-time: The heater should be deactivated as long as possible as the power consumption of the heater is high. Growing ice on the evaporator decreases the cooling efficiency of the evaporator and therefore increases the energy consumption of the cooling function. The overall system energy efficiency can be optimized by activating the heater when a certain amount of ice has grown.

Heater on-time: As the heater power consumption is high, the heater should only be activated until all the ice has melted, not l...