Condenser Dryer Load Detection Using Temperature and Condensate

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Solution Overview

Problem

Condensation dryers often over-dry laundry when loaded below nominal capacity, leading to inefficient energy use and prolonged drying times, as existing methods for determining laundry load are inaccurate and fail to adapt the drying process accordingly.

Innovation Solution

A condensation dryer with multiple temperature sensors and a control device that determines the laundry load by analyzing the time profiles of temperature changes and condensed water, allowing for precise adaptation of the drying process based on the load, using a condensation rate calculation and sensors for accurate condensate measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the drying process is aligned with nominal load, then the dryer can operate with a standard drying program, but the laundry is over-dried with lower loads leading to unnecessary energy consumption and excessively long drying times

Engineering Contradiction:
ImproveAdaptability of drying process to loadVSAvoidEnergy consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary action by determining the laundry load before the drying process begins. The control device calculates the load based on temperature change measurements taken during the initial heating phase, allowing the drying program to be adapted in advance to match the actual load size, thereby avoiding energy waste from over-drying

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by continuously monitoring the temperature change of process air during the heating phase and using this information to calculate the actual laundry load. This feedback loop enables the control device to adjust the drying program parameters based on the determined load, optimizing energy consumption while achieving complete drying

Inventive Principle:
Principle #23Feedback

2Adaptability or versatility

If the drying process is aligned with nominal load, then the dryer follows a fixed drying program, but the drying time becomes excessively long for lower loads

Engineering Contradiction:
ImproveAdaptability of drying program to loadVSAvoidDrying time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The control device performs preliminary load determination during the heating phase before the main drying process begins. Based on the calculated load, the drying program is adapted in advance to set appropriate drying times, ensuring that smaller loads are dried quickly without unnecessary waiting time while larger loads receive adequate drying duration

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies dynamics by making the drying program flexible and adaptive rather than fixed. The control device adjusts drying program parameters such as duration and intensity based on the dynamically determined load, allowing the system to optimize drying time for each specific loading condition

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If existing load determination methods are used, then the dryer attempts to estimate load, but the methods are inaccurate and fail to adapt the drying process accordingly

Engineering Contradiction:
ImproveLoad determination accuracyVSAvoidAbility to adapt drying process to load
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent replaces inaccurate mechanical or simple sensing load determination methods with a thermodynamic measurement system. By measuring the temperature change of process air during the heating phase and calculating the load based on thermal physics principles, the system achieves high measurement precision that enables accurate adaptation of the drying process

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement parameter from direct mechanical load sensing to indirect thermal parameter measurement. By monitoring temperature change (ΔT) of the process air and using this thermal parameter to calculate the laundry load, the system achieves more precise and reliable load determination that directly supports drying program adaptation

Inventive Principle:
Principle #35Parameter changes

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 approach ensures optimal drying results, reduces energy consumption, and allows for user-defined dryness levels, protecting the laundry and minimizing energy waste.

Implementation Method 1

a heat exchanger for the condensation of water from moist, warm process air

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 2

The warm and humid process air is cooled down in it, so that the water it contains condenses

Methodology Applied
Scientific EffectPhase change: Phase Change

Data Source

PatentEP2895652B1Condenser dryer with means for determining the loading, and method for operating the same
Publication Date: 2016.08.24 BSH HAUSGERATE GMBH
  • EP2895652B1 patent drawingFigure 1
  • EP2895652B1 patent drawingFigure 2
  • EP2895652B1 patent drawing

AI summary

The invention relates to a condenser dryer (1) having a process‑air channel (2), a drum (3) for accommodating items of laundry, a heat exchanger (5, 15) for condensing water from humid/warm process air, a control device 10, at least one temperature sensor (27, 28, 29, 30) and a means (11, 20, 32) for determining the quantity of water condensed in the heat exchanger, wherein the at least one temperature sensor (27, 28, 29, 30) is arranged in a cooling‑medium channel (24) and/or in the process‑air channel (2) and the control device (10) is intended to determine loading of the drum (3) with items of laundry with reference to progression over time of the temperature measured by the at least one temperature sensor (27, 28, 29, 30) and progression over time of the quantity of water condensed. The invention also relates to a method which is suitable for operating said dryer.