Refrigeration System Pressure Control Based on Utilization Unit Height

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Solution Overview

Problem

Conventional refrigeration systems face inefficiencies when controlling refrigerant pressure across multiple utilization units of varying heights and capacities, leading to increased pressure and reduced energy efficiency.

Innovation Solution

A refrigeration system that detects the height-associated values of each utilization unit and performs pressure control based on the operational units, using adjustable expansion valves and monitoring refrigerant state changes to optimize pressure, thereby avoiding unnecessary pressure increases and enhancing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the average value of heights or the height of the utilization unit with the largest refrigerant flow rate is calculated as the height of the connection pipe, then the system can operate with all utilization units in mind, but the refrigerant pressure becomes higher than necessary when not all units are operating, reducing energy efficiency

Engineering Contradiction:
Improvesystem operation with multiple utilization unitsVSAvoidenergy efficiency
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent applies dynamics by making the pressure control adaptive to changing operating conditions. The control unit dynamically adjusts the target high pressure value based on which utilization units are currently operating and their respective heights. This allows the system to transition from a static pressure control approach (using average or maximum height for all units) to a dynamic approach that optimizes pressure for the current operational configuration, thereby reducing energy consumption when not all units are active.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements local quality by applying different pressure control strategies to different operational scenarios. Instead of using a single global pressure setting for all utilization units, the control unit determines the appropriate target high pressure value based on the specific combination of operating units. This localized approach ensures that pressure is optimized for the actual demand at each moment, avoiding unnecessary pressure increases and improving energy efficiency.

Inventive Principle:
Principle #3Local quality

2Reliability

If the refrigerant pressure is increased to ensure adequate pressure for all possible utilization units, then all units can be served, but the pressure becomes excessive when fewer units are operating, leading to inefficient operation

Engineering Contradiction:
Improverefrigerant pressure adequacyVSAvoidsystem efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent employs feedback by continuously monitoring the operational status of utilization units and using this information to adjust the target high pressure value. The control unit receives feedback about which units are operating and their heights, then dynamically determines the appropriate pressure setting. This feedback mechanism ensures that pressure is maintained at adequate levels for reliability while avoiding excessive pressure that would reduce efficiency, creating an optimal balance based on real-time system state.

Inventive Principle:
Principle #23Feedback

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 operates with greater energy efficiency by ensuring refrigerant pressure is optimized based on the height of operational units, reducing energy consumption and avoiding costly sensor installations.

Implementation Method 1

the pressure control unit performs the refrigerant pressure control on the basis of the height-associated values of the utilization units that have determined to be in operation

Methodology Applied
Scientific EffectPressure reduction: Pressure Drop

Implementation Method 2

the cold heat that the refrigerant has obtained as a result of releasing heat in the heat source-side heat exchanger

Methodology Applied
Scientific EffectHeat release: Heat Exchanger

Implementation Method 3

the refrigerant evaporates in the utilization-side heat exchangers

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP2767776B1Refrigeration system
Publication Date: 2020.07.01 DAIKIN INDUSTRIES LTD
  • EP2767776B1 patent drawingFigure 1
  • EP2767776B1 patent drawingFigure 2
  • EP2767776B1 patent drawingFigure 3

AI summary

In order to allow a refrigeration system including plural utilization units to operate with greater efficiency than conventionally, an air conditioning system of the present invention is equipped with an outdoor unit, plural outdoor units, a height detection unit (97), and a normal operation control unit (92). The height detection unit (97) detects, in regard to each of the indoor units, heights that are vertical distances between the outdoor unit and the indoor units. The normal operation control unit (92) determines whether each of the indoor units is in operation or stopped and performs refrigerant pressure control on the basis of the heights of the indoor units that have been determined to be in operation.