Flooded evaporator

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Solution Overview

Problem

Existing free-cooling systems in cooling systems are limited in efficiency and flexibility as they can only operate in either cooling or free-cooling modes, and the pump's energy expense further reduces efficiency in free-cooling mode, with evaporators causing pressure drops that harm compressor components.

Innovation Solution

A cooling system with a refrigeration circuit including an additional evaporator that allows for both traditional and free-cooling modes, bypassing the compressor and expansion device, and utilizing a flooded evaporator design without distributor and retaining plates to minimize pressure drops, enabling efficient heat exchange and operation without a pump in free-cooling mode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If distributor plate and retaining fluid plate are used in flooded evaporator, then liquid discharge and liquid drops are prevented, but pressure drops in the refrigeration circuit increase

Engineering Contradiction:
Improveprevention of liquid discharge and liquid dropsVSAvoidpressure drops in refrigeration circuit
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The patent removes the distributor plate and retaining fluid plate from the flooded evaporator design. By extracting these components, the system eliminates the pressure drops they cause while implementing alternative measures (such as proper evaporator geometry and flow distribution) to prevent liquid discharge and liquid drops, thus resolving the contradiction between reliability and pressure loss.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The evaporator is divided into distinct functional zones: a liquid accumulation zone at the bottom and a vapor rise zone at the top. This segmentation allows liquid to accumulate safely in the lower zone without discharge, while vapor rises to the outlet, preventing liquid drops without requiring mechanical plates that would cause pressure drops.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If pump is used in free-cooling mode, then refrigerant circulation is enabled, but energy expense increases

Engineering Contradiction:
Improverefrigerant circulation in free-cooling modeVSAvoidenergy expense of pump
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The system uses the temperature difference between the evaporator and condenser to create natural circulation of the refrigerant in free-cooling mode. The cooler evaporator creates lower pressure that draws refrigerant from the condenser, eliminating the need for an active pump and reducing energy consumption while maintaining proper refrigerant flow.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The mechanical pump system is replaced with a passive thermal-driven circulation system. By utilizing the natural temperature and pressure differential between evaporator and condenser, the system achieves refrigerant circulation without mechanical pumping, thereby eliminating the energy expense associated with pump operation.

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

3Productivity

If evaporator is designed without bypass, then heat exchange efficiency is maximized, but system flexibility and efficiency are reduced

Engineering Contradiction:
Improveheat exchange efficiencyVSAvoidsystem flexibility between cooling modes
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The system incorporates dynamic flow control mechanisms that allow the evaporator to adapt its operation between different cooling modes. The evaporator can operate in high-efficiency mode during traditional cooling and switch to free-cooling mode when ambient conditions permit, with the ability to dynamically adjust refrigerant flow distribution to optimize performance for each operating condition.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The evaporator is designed to serve multiple functions: it acts as the primary heat exchange component in traditional cooling mode and simultaneously serves as a free-cooling heat exchanger when ambient air is sufficiently cool. This multi-functionality allows the system to maintain high heat exchange efficiency while adapting to different operating modes, thereby achieving both productivity and versatility.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 achieves enhanced efficiency and flexibility by allowing operation in hybrid modes, reducing pressure drops, and eliminating the need for a pump in free-cooling, thus improving the refrigeration cycle performance and compressor safety.

Implementation Method 1

the heat is transferred from the water to the refrigerant fluid, resulting in an evaporation of the refrigerant fluid and a cooling of the water

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

The condenser is configured for providing a heat transfer from the refrigerant fluid (flowing in the refrigeration circuit) to ambient air

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

The compressor is configured for compressing the refrigerant fluid (flowing in the refrigeration circuit)

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3627073A1Flooded evaporator
Publication Date: 2020.03.25 DAIKIN APPLIED EURO SPA
  • EP3627073A1 patent drawingFigure 1
  • EP3627073A1 patent drawingFigure 2
  • EP3627073A1 patent drawingFigure 3

AI summary

A flooded evaporator (6) for a cooling system (1) comprises: a shell (60) delimiting an internal volume; a set of pipes (67) passing through the internal volume and configured for circulating a liquid to be cooled; an inlet (61) at a lower portion (602) of the shell (60), to receive a refrigerant fluid in a liquid phase; an outlet (62) at an upper portion (601) of the shell (60), to release the refrigerant fluid in a vapor phase; an additional outlet (63), provided at the lower portion (602) of the shell (60), to release the refrigerant fluid in the liquid phase. [Figure 5A]