Preconditioned air unit with variable frequency driving
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Solution Overview
Problem
Existing preconditioned air units for aircraft on the ground are inefficient in terms of cost, energy consumption, and environmental impact due to reliance on auxiliary power units, which consume jet fuel, generate noise, and produce CO2 emissions.
Innovation Solution
A preconditioned air unit with a housing, centrifugal blower, and variable frequency drivers for refrigeration systems that allow for adjustable cooling capacity, reducing energy consumption and extending equipment life, along with modular self-contained cooling modules and a central controller for flexible operation and power management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the compressor is supplied from the mains supply with fixed frequency AC voltage, then the system structure is simple, but the maximum capacity of the compressor is limited and cannot be adjusted according to cooling requirements
Solution Approach 1:
The patent applies a variable frequency driver to the compressor motor, transforming the fixed-speed compression system into a variable-speed system. This allows the compressor capacity to be dynamically adjusted according to actual cooling requirements, resolving the contradiction between adaptability and structural simplicity by introducing controlled complexity only where needed for capacity adjustment.
Solution Approach 2:
The patent changes the electrical parameters (frequency and voltage) supplied to the compressor motor through a variable frequency driver. By varying the frequency from 0-50Hz and adjusting voltage accordingly, the compressor capacity can be continuously adjusted, achieving adaptable cooling capacity while maintaining a relatively simple overall system structure.
2Reliability
If the compressor operates continuously at maximum capacity, then the cooling requirement can be met, but the power consumption increases and equipment life decreases
Solution Approach 1:
The variable frequency driver enables dynamic adjustment of compressor speed based on actual cooling load. The compressor operates at optimal speed rather than continuously at maximum capacity, reducing power consumption while extending equipment life through reduced mechanical stress and heat generation.
Solution Approach 2:
The system uses temperature sensors and control logic to monitor cooling requirements and adjust compressor operation accordingly. This feedback mechanism ensures the compressor runs only at the necessary capacity, avoiding unnecessary energy consumption and reducing wear to extend equipment life.
3Ease of operation
If the APU is used to drive air-conditioning equipment, then the aircraft can be cooled on the ground, but jet fuel consumption increases, acoustic noise is generated, and CO2 emissions are produced
Solution Approach 1:
The patent extracts the air conditioning function from the APU system by providing a separate ground-based pre-cooling unit. This separates the cooling function from the propulsion system, eliminating fuel consumption, noise, and emissions associated with APU operation while maintaining aircraft cooling capability.
Solution Approach 2:
The pre-cooling unit acts as an intermediary system that prepares the air before it enters the aircraft's air conditioning system. By pre-cooling the air on the ground using electricity instead of jet fuel, the system eliminates harmful emissions and noise while maintaining the required cooling performance.
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 reduces energy consumption, extends equipment life, and minimizes environmental impact by optimizing cooling capacity and power usage, while maintaining efficient and flexible operation for various aircraft types.
Implementation Method 1
the output voltage and frequency of the variable frequency driver are varied to control the at least one compressor in accordance with the current cooling requirement
Implementation Method 2
at least one refrigeration system, each of which comprises at least one compressor, at least one condenser, at least one expansion valve, and at least one evaporator connected in a refrigerant flow circuit containing a refrigerant
Implementation Method 3
the outer walls of the flow duct may be provided with a layer of heat insulation material
Implementation Method 4
The blower is preferably a highly efficient centrifugal fan
Data Source
AI summary
A preconditioned air unit for supplying preconditioned air to an aircraft parked on the ground, the preconditioned air unit comprising a housing accommodating a flow duct with an air inlet for ambient air and an air outlet for connection to the parked aircraft, a blower connected with the flow duct for generation of an air flow from the air inlet toward the air outlet, at least one refrigeration system, each of which includes at least one compressor, at least one condenser, at least one expansion valve, and at least one evaporator connected in a flow circuit containing a refrigerant, and wherein the at least one evaporator interacts with the air flow in the flow duct, and at least one variable frequency driver for power supply of at least one of the at least one compressor of the at least one refrigeration system.