Absorption Refrigerator Control for Winter Freezer Cooling

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Solution Overview

Problem

Absorption refrigerators face performance deterioration due to ambient temperature variations, particularly when left unused during winter, leading to inadequate cooling of the freezer compartment due to a running time determined by the fresh food compartment's temperature.

Innovation Solution

A control function that monitors the temperature and running time of the absorption refrigerating system, activating a heat supply in the fresh food compartment when the system is off for a predetermined period to maintain optimal temperatures in both compartments, using either a light source or a separate heating element to ensure the refrigerating system is activated when necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the refrigerator is left in operation during winter at low ambient temperature, then the fresh food compartment remains cool, but the running time is reduced causing the freezer compartment to become warmer

Engineering Contradiction:

Improvefresh food compartment temperatureVSAvoidfreezer temperature maintenance

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The control function detects prolonged idle periods and low ambient temperature conditions, then proactively extends the refrigerating system running time before the freezer compartment temperature rises to problematic levels. This preliminary intervention maintains freezer reliability during extended periods when the refrigerator would normally be idle.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control function dynamically adjusts the refrigerating system operation parameters based on ambient temperature and usage patterns. During winter idle periods, it modifies the cut-out temperature threshold or extends the minimum running time, changing the operational parameters to ensure adequate freezer cooling even when the fresh food compartment would normally be sufficiently cool to stop operation.

Inventive Principle:

Principle #35Parameter changes

2Temperature

If the refrigerating system runs continuously to maintain freezer temperature at low ambient temperatures, then the freezer compartment temperature is maintained, but energy consumption increases

Engineering Contradiction:

Improvefreezer compartment temperatureVSAvoidenergy consumption

Core Design Contradiction:

TemperatureVSUse of energy by moving object

Solution Approach 1:

The control function extends refrigerating system operation in advance during predicted idle periods at low ambient temperatures, rather than allowing the freezer temperature to rise and then requiring extended recovery cooling. This timing optimization reduces total energy consumption compared to reactive temperature correction.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control function implements periodic monitoring of ambient temperature, usage patterns, and compartment temperatures to determine optimal refrigerating system operation cycles. This periodic assessment allows the system to extend running time only when necessary based on predicted conditions, avoiding continuous operation and reducing unnecessary energy consumption while maintaining freezer temperature reliability.

Inventive Principle:

Principle #19Periodic action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution maintains consistent performance across varying ambient conditions, preventing the freezer compartment from overheating at low temperatures and enhancing the refrigerator's all-year functionality and reliability.

Implementation Method 1

supplying heat to the first refrigerator compartment, when the time period exceeds a predetermined time period

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The evaporator comprises a first tube section arranged to absorb heat from the freezer compartment and a second tube section arranged to absorb heat from the fresh food compartment, thereby lowering the temperature within the compartments

Methodology Applied

Scientific EffectHeat absorption: Absorption (physical)

Implementation Method 3

An absorption refrigerator comprises an absorption refrigerating system including a condenser, a heater, an evaporator and an absorption vessel

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentUS7412837B2Method for use in controlling an absorption refrigerating system, and an absorption refrigerator

Publication Date: 2008.08.19 DOMETIC APPLIANCES

AI summary

The invention relates to a method for controlling a running time of an absorption refrigerating system of an absorption refrigerator, which absorption refrigerator comprises two differently tempered refrigerator compartments. The method comprises the steps of: monitoring the temperature in a first compartment; activating the refrigerating system when the temperature sensed in the first compartment exceeds a predetermined value; de-activating the refrigerating system when a cut-out temperature is reached; monitoring the time period during which the absorption refrigerating system is turned off; and supplying heat to the first refrigerator compartment, when the time period exceeds a predetermined time period. The invention also relates to a microcontroller, computer program product and to an absorption refrigerator comprising means for performing the inventive method.