Chiller Head Pressure Control with Dynamic Setpoint Adjustment

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Solution Overview

Problem

Existing chiller systems face inefficiencies due to fixed Head Pressure Control setpoints, leading to unnecessary power consumption and reduced performance under varying load and ambient temperature conditions.

Innovation Solution

A chiller system with a control system that dynamically adjusts the Head Pressure Control setpoint based on ambient temperature and load, using a pre-determined algorithm to minimize combined compressor and fan power input, and employing a load balancing valve to manage pressure ratios and initiate additional compressors for increased capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a fixed Head Pressure Control setpoint is used, then the control system is simple, but energy efficiency deteriorates under varying load and ambient temperature conditions

Engineering Contradiction:
Improvecontrol system complexityVSAvoidpower consumption
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic adjustment of the Head Pressure Control setpoint based on real-time ambient temperature and load conditions. The control system continuously modifies the setpoint within a range (e.g., 25-45 PSI) rather than maintaining a fixed value, allowing the chiller to adapt to varying operating conditions and minimize power consumption at both compressor and fan.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters of the chiller system by adjusting the Head Pressure Control setpoint dynamically. By varying this critical parameter based on ambient temperature and load, the system optimizes energy efficiency without requiring complete system redesign, achieving reduced power consumption through parameter optimization.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If the Head Pressure Control setpoint is adjusted dynamically, then energy efficiency improves, but control system complexity increases

Engineering Contradiction:
Improvepower consumptionVSAvoidcontrol system complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent employs feedback mechanisms where sensors continuously monitor ambient temperature and system load conditions. This information feeds back to the control system, which automatically adjusts the Head Pressure Control setpoint accordingly. The feedback loop enables intelligent, adaptive control that improves energy efficiency without requiring complex manual intervention.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control system performs self-adjustment based on pre-programmed algorithms and real-time sensor data. The system automatically determines the optimal Head Pressure Control setpoint without external intervention, reducing the need for complex user programming while achieving energy optimization through autonomous decision-making.

Inventive Principle:
Principle #25Self-service

3Use of energy by moving object

If the compression ratio is reduced, then compressor efficiency improves, but additional pressure management components are required

Engineering Contradiction:
Improvecompressor power inputVSAvoidpressure management components
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent introduces a bypass valve as an intermediary component that allows excess refrigerant to bypass the compressor discharge line. This mediator enables pressure management by redirecting flow to maintain optimal compression ratio, improving compressor efficiency without requiring complete system redesign.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the refrigerant flow path by creating a bypass route that divides the main flow into two paths: one through the normal compression cycle and another through the bypass valve. This segmentation allows independent control of compression ratio and pressure management, enabling efficiency improvements while managing system complexity through modular flow control.

Inventive Principle:
Principle #1Segmentation

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 optimizes energy efficiency and reduces power requirements by adjusting the Head Pressure Control setpoint to match changing conditions, ensuring efficient operation across a range of loads and temperatures, thereby minimizing energy consumption and operating costs.

Implementation Method 1

a condenser having an inlet connected with the compressor outlet and an outlet

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

a condenser having an inlet connected with the compressor outlet and an outlet

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

an evaporator having an inlet connected with the expansion valve outlet and an outlet connected with the compressor inlet

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 4

an evaporator having an inlet connected with the expansion valve outlet and an outlet connected with the compressor inlet

Methodology Applied
Scientific EffectHeat absorption: Absorption (physical)

Implementation Method 5

a plurality of compressors having inlets and outlets

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 6

an expansion valve having an inlet and an outlet, the inlet being in fluid communication with the condenser outlet

Methodology Applied
Scientific EffectPressure reduction: Depressurisation

Data Source

PatentEP2313709B1Chiller with setpoint adjustment
Publication Date: 2020.03.25 MODINE MFG CO
  • EP2313709B1 patent drawingFigure 1
  • EP2313709B1 patent drawingFigure 2
  • EP2313709B1 patent drawingFigure 3a~3d

AI summary

A chiller system includes a compressor operable at a compressor speed between a first speed and a second speed to deliver a flow of compressed fluid to a manifold at a compressor pressure and a condenser in fluid communication with the manifold to receive the compressed fluid. A condenser fan is operable at a fan speed between a minimum fan speed and a maximum fan speed to direct a cooling flow to the condenser to cool the compressed fluid and an evaporator is positioned to receive the flow of compressed fluid and operable to cool a second fluid. A controller is operable at least partially in response to a measured temperature of the second fluid and a measured temperature of the cooling flow to determine a desired pressure and to vary the compressor speed and the fan speed such that the compressor pressure equals the desired pressure.