Absorption Air Conditioner Pressure-Loss Control Against Crystallization

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Solution Overview

Problem

Existing absorption air conditioning systems face challenges in precisely regulating the concentration of absorbent fluids to prevent crystallization and ensure efficient operation, particularly in vehicles where responsiveness and speed are critical.

Innovation Solution

A method that calculates the concentration of absorbent fluid by measuring refrigerant vapor pressure and absorbent fluid temperature, adjusting pressure loss in the conduit between the desorber and condenser using a valve to control condensation, thereby managing the risk of crystallization and optimizing system performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the concentration of absorbent fluid is regulated to prevent crystallization, then the reliability of the air conditioning system is improved, but the device complexity increases due to additional sensors and control mechanisms

Engineering Contradiction:
Improvecrystallization preventionVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system continuously measures refrigerant vapor pressure in the desorber and solution temperature, calculates concentration based on these measurements, and adjusts the pressure loss control valve accordingly to maintain concentration below the critical value and prevent crystallization

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces direct mechanical concentration measurement and adjustment mechanisms with a computational approach that calculates concentration from pressure and temperature measurements, simplifying the physical control system while maintaining reliability

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

2Reliability

If existing regulation methods are used to control absorbent fluid concentration, then crystallization risk is managed, but the responsiveness and speed of control are insufficient

Engineering Contradiction:
Improvecrystallization risk managementVSAvoidcontrol responsiveness
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The system implements continuous real-time monitoring of pressure and temperature with immediate calculation of concentration and automatic adjustment of the control valve, providing fast responsiveness to changing operating conditions and preventing crystallization risk

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control system automatically calculates concentration and adjusts the pressure loss valve without external intervention, enabling rapid self-regulation in response to changing system conditions

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If pressure loss in the conduit is increased to stop condensation and prevent crystallization, then the concentration control precision is improved, but the energy efficiency deteriorates due to disrupted refrigerant flow

Engineering Contradiction:
Improveconcentration control precisionVSAvoidenergy efficiency
Core Design Contradiction:
Manufacturing precisionVSLoss of energy

Solution Approach 1:

The system dynamically adjusts the pressure loss control valve based on real-time concentration calculations, increasing pressure loss only when and where needed to prevent crystallization, rather than maintaining constant high pressure loss, thus balancing precision with energy efficiency

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the pressure loss parameter dynamically based on calculated concentration levels, adjusting it only when concentration approaches the critical value, thereby maintaining precision when needed while minimizing energy loss during normal operation

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 method provides faster and more precise control over the absorbent fluid concentration, reducing the risk of crystallization and enhancing the air conditioning system's responsiveness and efficiency, especially in automotive applications.

Implementation Method 1

when the desorber is heated, the more volatile of the two, the refrigerant, evaporates

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

This refrigerant is then condensed in the condenser by cooling

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

The absorber allows the solution to fix the refrigerant molecules

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 4

The solution/refrigerant reaction is exothermic

Methodology Applied
Scientific EffectExothermic reaction: Exothermic Reaction

Data Source

PatentEP2193316B1Method for calculating and adjusting the concentration of absorbing fluid in an absorption air conditioning device, and absorption air conditioning device for implementing said method
Publication Date: 2016.11.02 PSA AUTOMOBILES SA
  • EP2193316B1 patent drawingFigure 1~2
  • EP2193316B1 patent drawingFigure 3~4
  • EP2193316B1 patent drawing

AI summary

The invention relates to an absorption air conditioner that comprises a desorber (100), a condenser, an evaporator and an absorber, wherein the absorbing fluid may consist of lithium bromide. The method comprises the following steps: calculating the concentration of the absorbing fluid solution at the outlet of the desorber (100); and comparing the calculated concentration with a predetermined critical value and, if the calculated concentration gets closer to the predetermined critical value, increasing the charge loss in the duct (20) connecting the desorber (100) to the condenser, which interrupts the condensation in the condenser and results in a pressure increase in the desorber that stops the desorption and in a concentration increase, the charge loss being on the other hand reduced for resuming the desorption when the calculated concentration deviates from the predetermined critical value. The invention can be used in automobiles and absorption air-conditioners.