Refrigeration System Free-Cooling Control to Minimize Power Input

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Solution Overview

Problem

Traditional refrigeration systems inefficiently manage power input by maximizing fan speed of free cooling systems before activating mechanical cooling systems, leading to higher energy consumption.

Innovation Solution

Implementing a control system that adjusts fan speed and compressor operation based on ambient temperature and cooling load demand, activating the compressor before maximum fan speed is reached to minimize overall power input.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the fan speed of the free cooling system is maximized before activating the mechanical cooling system, then the cooling capacity is sufficient to meet the demand, but the power input and energy consumption increase

Engineering Contradiction:
Improvecooling capacityVSAvoidpower input
Core Design Contradiction:
PowerVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts fan speed based on real-time cooling load demands and ambient conditions rather than operating at fixed maximum speed. The controller continuously monitors temperature and modulates fan speed to provide恰好 enough free cooling capacity, avoiding unnecessary energy consumption while maintaining sufficient cooling effect.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the operating parameters of the fan (speed) based on varying cooling demands and ambient temperatures. By adjusting fan speed as a variable parameter rather than maintaining it at maximum, the system optimizes the balance between cooling capacity and power consumption, activating mechanical cooling only when free cooling can no longer meet the demand.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If the compressor is activated earlier before maximum fan speed is reached, then the overall power input is minimized, but the control system complexity increases

Engineering Contradiction:
Improveoverall power inputVSAvoidcontrol system
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The control system continuously monitors ambient temperature, cooling load demand, and system performance, using this feedback to determine the optimal moment to activate the compressor. This feedback mechanism enables the system to transition from free cooling to mechanical cooling at the precise point where it becomes energy-efficient to do so, minimizing overall power input while managing control complexity through automated decision-making.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary assessment of cooling demands and ambient conditions to determine when compressor activation will be most efficient. By evaluating conditions in advance and preparing for the transition from free cooling to mechanical cooling, the system can activate the compressor at the optimal moment rather than reactively, thereby minimizing energy consumption.

Inventive Principle:
Principle #10Preliminary action

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 reduces energy consumption and enhances the efficiency of the refrigeration system by optimizing the operation of both free and mechanical cooling systems.

Implementation Method 1

the free cooling system may include a liquid-to-air heat exchanger

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

liquid-to-air heat exchanger... used throughout industry and in many heating, ventilating, and air conditioning applications

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

In the evaporator, liquid or primarily liquid refrigerant is evaporated by drawing thermal energy from an air flow stream and/or a cooling fluid

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 4

drawing thermal energy from an air flow stream and/or a cooling fluid

Methodology Applied
Scientific EffectHeat absorption: Absorption (physical)

Implementation Method 5

In the condenser, the refrigerant is de-superheated, condensed, and sub-cooled

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 6

the refrigerant is de-superheated, condensed, and sub-cooled

Methodology Applied
Scientific EffectHeat rejection: Heat Exchanger

Data Source

PatentEP3500805B1Systems and methods for controlling a refrigeration system
Publication Date: 2022.03.09 JOHNSON CONTROLS TYCO IP HLDG LLP
  • EP3500805B1 patent drawingFigure 1
  • EP3500805B1 patent drawingFigure 2
  • EP3500805B1 patent drawingFigure 3

AI summary

A refrigeration system includes a heat exchanger (204) configured to place a cooling fluid in a heat exchange relationship with a working fluid, a free-cooling circuit having a pump (216) configured to circulate the working fluid through the heat exchanger and a condenser (206), a flow control valve (210) configured to control a flow rate of the working fluid to the condenser, a condenser bypass valve (212) configured to control a flow rate of the working fluid that bypasses the condenser, and a controller (78) configured to adjust a position of the flow control valve, a position of the condenser bypass valve, a speed of a fan (208) of the condenser, a speed of the pump, and a temperature of a heater (218) based on an ambient temperature, a temperature of the working fluid leaving the condenser, the position of the flow control valve, the position of the condenser bypass valve, or a combination thereof.