VFD Inverter Cooling Using Intermediary Multi-Loop Fluid Circuits
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Solution Overview
Problem
Existing cooling systems for electronic equipment, particularly inverter cooling systems, face challenges in maintaining tight temperature and humidity control due to variable environmental and cooling media conditions, leading to inefficiencies and safety limitations, which restrict the operating capacity of compressors and chillers.
Innovation Solution
The system employs a stable temperature-pumped cooling fluid from an external source to cool compressor motor inverters, using a multi-circuit fluid management system that includes free-cooling and mechanical sub-cooling, allowing for precise temperature control and reducing the need for safety sensors and limiting parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If condenser water or refrigerant is pumped through the inverter's heat exchanger to cool the inverter, then the inverter temperature is controlled, but the cooling system becomes complex and requires tight control of cooling media temperature and flow rate
Solution Approach 1:
The patent introduces an intermediary cooling circuit that uses condenser water as a heat source rather than directly pumping it through the inverter. A heat exchanger mediates between the condenser water loop and the inverter cooling loop, allowing temperature control without the complexity of directly controlling condenser water flow through the inverter.
Solution Approach 2:
The cooling system is segmented into separate loops: a primary condenser water loop and a secondary inverter cooling loop. This segmentation allows each loop to operate independently with its own flow rate and temperature control, reducing the overall system complexity while maintaining effective inverter cooling.
2Reliability
If safety sensors and limiting parameters are added to protect the inverter from environmental variables, then the inverter reliability is improved, but the operating capacity of compressors and chillers is restricted
Solution Approach 1:
The heat exchanger acts as an intermediary that isolates the inverter from direct exposure to variable environmental conditions. By using condenser water at controlled temperatures through the heat exchanger, the inverter operates in a stable thermal environment without requiring additional safety sensors or limiting parameters, thus maintaining full operating capacity.
Solution Approach 2:
The system uses the waste heat from condenser water to cool the inverter, creating a self-regulating system. The condenser water naturally provides cooling capacity that matches the inverter's heat generation, eliminating the need for external safety controls while maintaining reliability.
3Power
If the cooling fluid flow rate is increased to handle higher heat loads, then the inverter cooling capacity is improved, but the system energy consumption increases
Solution Approach 1:
The heat exchanger intermediary allows the system to use low-temperature condenser water effectively by providing a large temperature differential for heat transfer. This enables efficient cooling at lower flow rates, reducing pump energy consumption while maintaining adequate cooling capacity.
Solution Approach 2:
The system changes the temperature parameter of the cooling medium by utilizing condenser water at varying temperatures throughout the operating cycle. This parameter change allows the cooling system to adapt to different heat loads without increasing flow rate, thereby reducing energy consumption.
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 enables more efficient operation of compressors and chillers by maintaining precise temperature control, reducing safety limitations, and allowing seamless transitions between free cooling and mechanical cooling, thereby enhancing energy efficiency and reducing operational costs.
Implementation Method 1
a free-cooling system including a free-cooling device and a main heat exchanger in fluid communication with the free-cooling device. The free-cooling device is configured to cool the second fluid using atmospheric air
Implementation Method 2
The main heat exchanger is configured to transfer heat from the first fluid to the second fluid
Implementation Method 3
a mechanical sub-cooling system including a sub-cooling heat exchanger, a compressor, and a condenser heat exchanger. The compressor compresses the third fluid
Implementation Method 4
The condenser heat exchanger transfers heat from the compressed third fluid to the second fluid
Implementation Method 5
a variable frequency drive that controls a speed of the compressor motor as a function of a thermal load on the cooling system
Data Source
AI summary
Systems and methods for cooling an inverter of a variable frequency drive that drives a compressor in a cooling system for electronic equipment are disclosed. The system includes a first fluid circuit that cools electronic equipment using a first fluid flowing therethrough and a second fluid circuit that free cools a second fluid flowing therethrough. The second fluid circuit cools the first fluid using the free-cooled second fluid. The system further includes a third fluid circuit that mechanically cools the second fluid using a third fluid flowing therethrough as a function of the wet bulb temperature of atmospheric air. The third fluid circuit includes at least one compressor compresses the third fluid and is driven by a motor coupled to the variable frequency drive. At least a portion of the first fluid flowing through the third fluid circuit is diverted to cool the inverter of the variable frequency drive.