System and control method for a self-contained marine air conditioner unit
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Solution Overview
Problem
Conventional marine air conditioners face challenges in providing continuous cooling and comfort when a boat is stationary or cruising, due to high power demands and limited power sources, and lack efficient humidity control.
Innovation Solution
A self-contained marine air conditioning unit with a variable speed BLDC compressor, electronic expansion valve, and a controller that uses sensor data to optimize refrigerant flow, integrated with a condenser and evaporator, allowing for precise temperature and humidity control, and utilizing seawater for cooling, reducing energy consumption by 33% and eliminating the need for generators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional VAC air conditioners are used on boats, then cooling capability is provided, but high power consumption and amp spike at startup make them unusable when the boat is at anchor without a generator
Solution Approach 1:
The patent applies a variable speed BLDC compressor that can dynamically adjust its operating speed based on cooling demands and available power. The compressor operates at lower speeds during normal conditions and can ramp up when needed, eliminating the high amp spike of conventional fixed-speed compressors. This dynamic operation enables the air conditioner to run continuously on battery power at anchor without requiring a generator.
Solution Approach 2:
The system changes the operating parameters of the compressor by using pulse width modulation (PWM) control to vary the voltage and frequency supplied to the BLDC motor. This allows the compressor to operate efficiently across a wide range of speeds and loads, optimizing power consumption while maintaining cooling effectiveness. The electronic expansion valve also adjusts refrigerant flow parameters dynamically to match cooling demands.
2Ease of operation
If gasoline powered inverter generators are used to start VAC air conditioners, then cooling is enabled, but fire and carbon monoxide hazards are introduced
Solution Approach 1:
The patent replaces the mechanical combustion-based generator system with an electrical system using a BLDC motor driven by battery power and PWM control. This substitution eliminates all combustion-related hazards including fire risk and carbon monoxide production, while still providing the necessary starting torque and continuous operating power for the air conditioner compressor.
3Temperature
If conventional air conditioners are used, then temperature control is provided, but humidity control is not effectively addressed
Solution Approach 1:
The system incorporates humidity sensors that continuously monitor cabin humidity levels and provide feedback to the controller. The controller adjusts the operation of the compressor, electronic expansion valve, and condensate removal system based on this feedback to maintain optimal humidity levels. This active humidity control enhances passenger comfort and prevents issues related to excessive moisture such as mold growth and condensation.
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
Enables extended use without generators, reduces noise and power consumption, and provides effective humidity control, making it suitable for boats of all sizes, including smaller vessels, and can be installed easily with minimal maintenance.
Implementation Method 1
The compressor compresses the refrigerant to a high pressure and temperature, thereby transforming the refrigerant to a high pressure super heated vapor
Implementation Method 2
The condenser condenses the high pressure super heated vapor to a high pressure saturated liquid
Implementation Method 3
The condenser is surrounded by a water box and a set of tubes... The condenser condenses the high pressure super heated vapor to a high pressure saturated liquid
Implementation Method 4
The electronic expansion valve is located in the refrigerant line and configured to operate as a flow regulator to create a pressure difference between the condenser and the evaporator
Implementation Method 5
The evaporator absorbs heat from the air in the room, thereby transforming the refrigerant to a low pressure super heated vapor
Implementation Method 6
The evaporator absorbs heat from the air in the room
Implementation Method 7
The water pump can circulate water into the condenser to absorb heat from the refrigerant. The water can be drawn from a body of water in which the boat is floating
Data Source
AI summary
A marine air conditioning unit, according to various embodiments, can include a base plate having one or more mounting holes. A main unit is supported on the base plate comprising an evaporator, a compressor, a compressor driver, a condenser, an electronic expansion valve, a blower, an electrical pressure sensor and a condensation pan operatively coupled together. The compressor can be a variable speed inverter brushless direct current (BLDC) compressor. The electronic expansion valve can be located in a refrigerant line connecting the condenser to the evaporator. A controller can constantly receive and, using an algorithm, analyze sensor information from multiple sensors positioned within the main unit. Based on the sensor information, the controller can transmit a control signal to various components and further adjust the electronic expansion valve to control the precise amount of refrigerant to pass to the evaporator.