Cold Accumulator Layout for Stable Dew Point in Refrigerant Dryers

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Solution Overview

Problem

Existing refrigeration dryers face challenges in achieving energy-efficient regulation of refrigeration capacity, particularly in adapting to variable pressure fluid volume flows, moisture levels, and temperatures, with on-off control methods experiencing hysteresis issues and high installation costs due to large heat exchanger requirements.

Innovation Solution

A refrigeration dryer design that incorporates a spatially separated or integrated cold accumulator with enhanced thermal conductivity, using phase change materials and a discharge circuit for efficient energy use, allowing for gravitational or capillary-driven cold fluid transport to maintain constant pressure dew point and reduce energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a large capacity cold accumulator with good heat transfer is used to reduce temperature hysteresis, then temperature stability improves, but installation space and construction cost increase

Engineering Contradiction:
Improvetemperature stabilityVSAvoidinstallation space
Core Design Contradiction:
TemperatureVSVolume of stationary object

Solution Approach 1:

The heat exchanger surfaces are nested within the cold accumulator structure. The accumulator is designed with internal heat exchanger elements (such as coils or plates) embedded within its walls or core, allowing the heat transfer surfaces to be contained within the accumulator volume rather than requiring separate external heat exchanger components. This nesting approach achieves large heat transfer areas without proportionally increasing the overall installation space.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent combines multiple functions into the cold accumulator structure: cold storage, heat transfer, and thermal regulation. By merging the heat exchanger functionality directly into the accumulator design, the system eliminates the need for separate large external heat exchanger components, thereby reducing total installation space while maintaining effective heat transfer capacity for temperature stability.

Inventive Principle:
Principle #5Merging (Combining)

2Power

If large heat exchanger surfaces are provided to reduce temperature gradients, then heat transfer efficiency improves, but installation space and construction cost increase

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidconstruction cost
Core Design Contradiction:
PowerVSEase of manufacture

Solution Approach 1:

Heat exchanger surfaces are nested within the cold accumulator structure, with coils or plates embedded in the accumulator walls or core. This integration allows large heat transfer areas to be achieved without requiring separate external heat exchanger components, thereby reducing material costs (especially expensive materials like copper and aluminum) and simplifying manufacturing.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The heat exchanger surfaces are strategically positioned within the cold accumulator at locations where temperature gradients are most critical. By concentrating heat transfer surfaces in specific high-need areas rather than uniformly distributing them throughout a larger structure, the system achieves high heat transfer efficiency with reduced total material usage and lower construction costs.

Inventive Principle:
Principle #3Local quality

3Temperature

If the refrigerant compressor is switched on and off frequently to maintain constant pressure dew point, then temperature stability improves, but compressor life decreases

Engineering Contradiction:
Improvepressure dew point stabilityVSAvoidcompressor life
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The cold accumulator stores cold energy in advance during periods of low demand, pre-chilling the stored refrigerant or cooling medium. When the compressor needs to cycle off, the accumulator releases this pre-stored cold energy to maintain the pressure dew point, thereby reducing the frequency of compressor switching and extending compressor life while maintaining temperature stability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system utilizes phase change materials or thermal energy storage in the cold accumulator to change the thermal parameters over time. By storing cold energy in latent heat form during off-peak periods and releasing it during high-demand periods, the system smooths out temperature fluctuations without requiring frequent compressor cycling, thus protecting compressor reliability.

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 design significantly improves energy efficiency, especially in partial load situations, by allowing for flexible accumulator design and reduced installation costs while maintaining effective cooling capacity and constant pressure dew point.

Implementation Method 1

the cold storage medium undergoes a phase transition in its working area, in particular is designed as a so-called latent heat storage medium

Methodology Applied
Scientific EffectPhase transition: Phase Change

Implementation Method 2

the thermal capacity of the cold storage medium or the cold storage medium is increased in that the cold storage medium undergoes a phase transition in its working area, in particular is designed as a so-called latent heat storage medium

Methodology Applied
Scientific EffectLatent heat storage: Latent Heat

Implementation Method 3

The gravitational drive of the discharge circuit can be exclusive or non-exclusive depending on the specific embodiment of the invention

Methodology Applied
Scientific EffectGravitational drive: Gravitation

Implementation Method 4

the storage-side heat exchanger (20) with the cold storage medium (14) in thermal interaction

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2177255B8Refrigerant type dryer
Publication Date: 2012.08.29 KAESER KOMPRESSOREN SE

AI summary

The invention relates to a refrigeration dryer, in particular a compressed air refrigeration dryer, for drying a gaseous fluid while cooling the gaseous fluid by using a refrigeration fluid, comprising a pressure fluid-refrigerant heat exchanger (30) in which the gaseous fluid is cooled directly or indirectly by a primary circuit (16) and one or more refrigerant compressors (24) for operating the primary circuit and a cold accumulator (13) with an accumulator-side heat exchanger (20) which couples an accumulator discharge fluid to a cold accumulator medium (14), with pressure fluid-refrigerant heat exchangers (30) and cold accumulator (13) are in fluid connection or can be brought into fluid connection via a discharge circuit (15) for an accumulator discharge fluid, and wherein the cold accumulator (13) is arranged above the pressurized fluid/refrigerant heat exchanger (30) in relation to gravity in such a way that heated memory discharging luid via the discharge circuit (15) for cooling in the cold accumulator (13) is performed, there and then cooled again to the pressurized fluid-refrigerant heat exchanger (30).