Drying Chamber Dehumidifier Flow Split for Compact Heat Recovery

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Solution Overview

Problem

Existing drying systems, such as convection ovens and laundry dryers, face challenges with excessive space requirements and high construction costs due to the need for large gas-to-gas heat exchangers to maintain energy efficiency, making retrofitting difficult and inefficient.

Innovation Solution

A drying system that passes a reduced volume rate of process gas through a dehumidifier, optimizing the system to require less space by minimizing sensible heat transfer and utilizing a heat pump to transport more latent heat, allowing for retrofitting into existing systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a large gas-to-gas heat exchanger area is used to cool process gas before condensation, then energy efficiency is improved, but system space requirements increase excessively

Engineering Contradiction:
Improveenergy efficiencyVSAvoidsystem space requirements
Core Design Contradiction:
Loss of energyVSVolume of stationary object

Solution Approach 1:

The invention changes the flow rate parameter by reducing the volume rate of process gas passing through the dehumidifier to between 1-80% of the heater flow rate. This parameter change allows the system to achieve the same energy efficiency with a much smaller heat exchanger area, as less sensible heat needs to be transferred to reach the dew point temperature for condensation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Instead of cooling the entire process gas flow to the dew point, the invention applies partial cooling to a reduced portion of the gas flow. By passing only a fraction (1-80%) of the total flow through the dehumidifier, the system achieves sufficient condensation for energy recovery without requiring excessive heat exchanger area for complete cooling.

Inventive Principle:
Principle #16Partial or excessive action

2Volume of stationary object

If the volume rate of process gas through the dehumidifier is reduced, then space requirements decrease, but the ability to recover thermal energy is compromised

Engineering Contradiction:
Improvespace requirementsVSAvoidthermal energy recovery
Core Design Contradiction:
Volume of stationary objectVSLoss of energy

Solution Approach 1:

The invention optimizes the flow rate parameter to pass between 1-80% of the heater flow rate through the dehumidifier. This parameter change creates a balance where sufficient thermal energy is recovered from the condensed moisture while maintaining compact system dimensions. The reduced flow rate means less sensible heat is transferred, allowing smaller heat exchanger area while still achieving effective condensation.

Inventive Principle:
Principle #35Parameter changes

3Loss of energy

If a heat pump system is used to transfer thermal energy, then energy efficiency is improved, but the system complexity and cost increase

Engineering Contradiction:
Improveenergy efficiencyVSAvoidsystem complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The heat pump system is integrated with dual functionality: it serves as both the cooling mechanism for the dehumidifier and the heating source for the drying chamber. The cooler of the heat pump is positioned to receive process gas, while the heater is positioned to return heated gas to the drying chamber, allowing one system to perform multiple functions and reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention merges the cooling and heating functions into a single heat pump system. The thermal energy source (cooler) and thermal energy sink (heater) are integrated into one unit, allowing the system to recover thermal energy from the process gas and reuse it for heating, thereby improving energy efficiency while consolidating components to reduce complexity.

Inventive Principle:
Principle #5Merging (Combining)

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

The system achieves the same energy efficiency with reduced space requirements, enabling retrofitting into traditional ovens and dryers while minimizing energy waste and construction costs.

Implementation Method 1

a gas-to-gas heat exchanger arranged to cool process gas before entering the cooler and to heat process gas after exiting the cooler

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 2

a cooler for cooling process gas to a temperature at or below its dew point

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

a heat pump system having a thermal energy source arranged as the cooler of the dehumidifier and a thermal energy sink arranged as the heater

Methodology Applied
Scientific EffectHeat pump: Heat Exchanger

Data Source

PatentEP4671653A1Drying system
Publication Date: 2025.12.31 CIRCULAR ENERGY SYSTEMS APS
  • EP4671653A1 patent drawingFigure 1
  • EP4671653A1 patent drawingFigure 2
  • EP4671653A1 patent drawingFigure 3

AI summary

A drying system (1) includes a drying chamber (2), a heater (3) for heating process gas and a fan (4) for circulating process gas through the drying chamber and the heater, and a dehumidifier (5) for dehumidifying process gas from the drying chamber and sending it back to the drying chamber. The dehumidifier includes a cooler (6) for cooling process gas to a temperature at or below its dew point and a gas-to-gas heat exchanger (7) for cooling process gas before entering the cooler and for heating process gas after the cooler. A heat pump system (8) has a thermal energy source arranged as the cooler of the dehumidifier and a thermal energy sink arranged as the heater. The drying system is adapted to pass a volume rate of process gas through the dehumidifier which volume rate is smaller than a volume rate of process gas circulated through the heater.