Wind Turbine Gearbox Oil Cooling via Air Ejector

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Solution Overview

Problem

Current wind turbine gearbox oil coolers require large passive designs due to reliance on natural airflow, which increases size and costs, and conventional fan-driven systems are noisy and power-intensive.

Innovation Solution

The method employs an air ejector pump using effluent cooling air from the electric generator as motive air to draw cold air through a heat-exchanger, eliminating the need for fans and enabling a smaller, more efficient cooling system by utilizing existing air flows.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a passive oil cooler is used that relies solely on natural airflow, then the cooler can be mounted on the roof without motors or fans, but the cooling surface area becomes very large (several square meters) which increases size and costs

Engineering Contradiction:
Improvecooler structure complexityVSAvoidcooling surface area
Core Design Contradiction:
Device complexityVSArea of stationary object

Solution Approach 1:

The patent applies pneumatic principles by using an air ejector device that utilizes compressed air or gas flow to create a vacuum effect, actively drawing cooling air through the heat exchanger core. This pneumatic approach replaces the passive natural convection system, enabling effective cooling with a much smaller heat exchanger surface area while avoiding the complexity of motor-driven fans.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Productivity

If conventional fan-driven coolers are used to move air through the heat exchanger, then the cooling efficiency is high, but the system becomes noisy and consumes considerable electric power with additional costs for motor, fan, and shrouds

Engineering Contradiction:
Improvecooling efficiencyVSAvoidelectric power consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent replaces the mechanical fan and motor system with a pneumatic air ejector device. Instead of using an electric motor to drive a fan blade mechanically, the system uses compressed air or gas flow to create a vacuum that actively pulls cooling air through the heat exchanger. This substitution eliminates the need for electric motors, fans, and associated mechanical components, reducing noise and power consumption while maintaining high cooling efficiency.

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

3Ease of manufacture

If a passive cooler design is used without fans, then the system has lower costs and complexity, but the heat exchanger requires a very large cooling surface to extract sufficient heat from the oil

Engineering Contradiction:
Improvesystem cost and complexityVSAvoidheat exchanger volume
Core Design Contradiction:
Ease of manufactureVSVolume of stationary object

Solution Approach 1:

The patent employs pneumatic technology through an air ejector device that uses compressed air or gas to create a vacuum effect. This active pneumatic cooling system enables the use of a compact heat exchanger with small surface area, eliminating the need for large passive coolers while avoiding the complexity and cost of motor-driven fan systems.

Inventive Principle:
Principle #29Pneumatics and hydraulics

4Temperature

If motor driven fans are used to move air through the cooler core, then sufficient cooling capacity is achieved, but the system produces noise and requires additional components such as motors, fans, and shrouds

Engineering Contradiction:
Improveoil cooling capacityVSAvoidnoise
Core Design Contradiction:
TemperatureVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the noisy mechanical fan system with a silent pneumatic air ejector device. The air ejector uses compressed air or gas flow to create a vacuum that actively draws cooling air through the heat exchanger without any moving mechanical parts, fans, or motors. This eliminates noise generation while maintaining effective oil cooling capacity.

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

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 allows for effective heat extraction from gearbox oil with a significantly smaller heat-exchanger, reducing costs and structural requirements while minimizing noise and power consumption.

Implementation Method 1

directing effluent cooling air flow from the electric generator into an air ejector pump as using the effluent cooling air as motive air to draw a vacuum in the air ejector pump

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 2

The air ejector pump uses effluent cooling air from the electric generator as motive air to draw cold air through a heat-exchanger

Methodology Applied
Scientific EffectVenturi effect: Venturi Effect

Implementation Method 3

The heat-exchanger is disposed in-line with the cold air flow so that the cold air is drawn through the heat-exchanger, removes heat from the fluid circulated through the heat-exchanger

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 4

cold air is drawn through the heat-exchanger, removes heat from the fluid circulated through the heat-exchanger, and becomes heated air

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3992454B1Method and system for cooling a wind turbine gearbox oil heat-exchanger
Publication Date: 2023.06.21 GENERAL ELECTRIC RENOVABLES ESPANA SL
  • EP3992454B1 patent drawingFigure 1
  • EP3992454B1 patent drawingFigure 2
  • EP3992454B1 patent drawingFigure 3

AI summary

A method and system are provided for cooling a heat-exchanger in a wind turbine that has an electric generator with a cooling air flow directed therethrough. Effluent cooling air flow from the electric generator is directed into an air ejector pump and acts as motive air through the air ejector pump. Cold air is drawn into the air ejector pump by the vacuum generated by the motive air moving through the air ejector pump. The heat exchanger is disposed in-line with the cold air flow so that the cold air is drawn through the heat-exchanger, removes heat from the fluid circulated through the heat-exchanger, and becomes heated air that is combined with the motive air and discharged from the nacelle.