Motorcompressor Segmentation for Cooling Efficiency
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Solution Overview
Problem
Motorcompressors used in subsea applications face efficiency issues due to ineffective cooling at low pressures (below 20-30 bar) and high windage losses at pressures above 100 bar, leading to reduced motor performance and the need to operate at lower power levels.
Innovation Solution
Incorporating a pumping device, such as a turbomachinery or ejector, to transfer fluid from the motor chamber to the load chamber, reducing motor working pressure and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If process gas is used to cool the electric motor at high pressure (above 100 bar), then cooling effectiveness improves, but windage losses increase significantly
Solution Approach 1:
The system is divided into two separate chambers: a motor chamber containing the electric motor operating at lower pressure, and a load chamber containing the compressor operating at high process pressure. This segmentation allows each component to operate in its optimal pressure range, resolving the contradiction between cooling effectiveness and windage losses.
Solution Approach 2:
A pumping device acts as an intermediary between the motor chamber and load chamber, transferring fluid from the high-pressure load chamber to the low-pressure motor chamber. This intermediary mechanism enables the motor to receive cooling fluid without being exposed to the high pressures that cause windage losses.
2Loss of energy
If process gas is used to cool the electric motor at low pressure (below 20-30 bar), then windage losses are reduced, but cooling effectiveness becomes insufficient due to low gas density
Solution Approach 1:
The system separates the motor chamber from the load chamber, allowing the motor to operate in a low-pressure environment that minimizes windage losses while still receiving adequate cooling through the pumped fluid supply.
Solution Approach 2:
The pressure parameter in the motor chamber is changed from high process pressure to a lower operating pressure, optimizing the balance between cooling effectiveness and windage losses. The pumping device maintains appropriate fluid density for cooling without requiring high pressure.
3Power
If the motor operates at high process pressure (200 bar or more), then the motor delivers maximum rated power, but efficiency severely decreases due to high windage losses
Solution Approach 1:
The motor is segmented into a separate chamber that operates at lower pressure than the process gas, allowing the motor to maintain high efficiency while the load chamber handles the high-pressure compression to deliver maximum power.
Solution Approach 2:
The pumping device serves as an intermediary that connects the high-power load chamber with the high-efficiency motor chamber, enabling the motor to operate efficiently at lower pressure while still driving the high-power compression load.
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 solution effectively lowers motor chamber pressure, improving motor efficiency by operating with lower density fluids, thereby enhancing overall motorcompressor performance even at higher pressures.
Implementation Method 1
a pumping device configured to transfer a fluid present in the motor chamber to the load chamber so as to lower the pressure inside the motor chamber
Data Source
AI summary
A motorcompressor comprising an electric motor, a load, a shaft assembly, the electric motor and the load being mounted on the shaft assembly, a casing configured to completely house the electric motor, the load and the shaft assembly for its entire length, a divider located in the casing to define a motor chamber and a load chamber, the divider comprising at least a pumping device configured to transfer a part of the fluid present in the motor chamber to the load chamber so as to obtain in the motor chamber a pressure that is lower than a pressure at a load inlet.