Indoor Blower Airflow Profiles for Quiet HVAC Humidity Control
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Solution Overview
Problem
HVAC systems lack the ability to effectively control indoor air flowrate and noise levels, as well as humidity and temperature adjustments, which are essential for occupant comfort and energy efficiency, especially during varying operational phases and humidity sensing requirements.
Innovation Solution
A programmable microcontroller-based HVAC system controller that allows users to select and adjust indoor air flowrate through a pulse width modulated signal to the blower motor, enabling customizable air flow profiles during startup, shutdown, and continuous operation, integrating humidity and temperature sensors for optimal comfort and energy management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If air flowrate is increased to improve cooling efficiency, then cooling performance is improved, but noise level increases
Solution Approach 1:
The patent implements variable speed control of the indoor blower motor, allowing the air flowrate to be dynamically adjusted based on operational phase and user preferences. The system transitions from fixed speed to variable speed operation, enabling optimization of both cooling efficiency and noise levels at different times.
Solution Approach 2:
The system changes the operational parameters of the blower motor by implementing different air flow profiles (startup, shutdown, continuous operation) with specific flow rates and durations. This allows the system to operate at lower speeds during continuous operation to reduce noise while maintaining adequate cooling performance.
2Loss of energy
If air flowrate is reduced during shutdown to minimize heat transfer losses, then energy efficiency is improved, but cooling effect capture is reduced
Solution Approach 1:
The system implements a predetermined shutdown profile that maintains higher air flow rates for a specific duration after the compressor shuts off. This preliminary action allows the system to capture and distribute residual cooling effects in the ductwork before reducing air flow to minimize heat transfer losses from the ducts to the surrounding environment.
Solution Approach 2:
The shutdown phase is divided into periodic stages: an initial period with higher air flow to capture residual cooling, followed by a reduced air flow period to minimize heat transfer losses. This periodic variation in air flow rate optimizes both energy recovery and loss prevention.
3Quantity of substance
If air flowrate is reduced to improve humidity reduction, then dehumidification performance is improved, but air circulation is reduced
Solution Approach 1:
The system changes the air flow rate parameter to a reduced level during cooling operation to enhance dehumidification performance. By operating at lower air flow rates, the air spends more time in contact with the cooling coil, allowing for more effective moisture removal while maintaining acceptable air circulation through the dwelling.
4Adaptability or versatility
If variable speed control is implemented to meet multiple occupancy needs, then system adaptability is improved, but device complexity increases
Solution Approach 1:
The controller is designed to provide multiple functions through a single device: temperature control, humidity control, variable speed blower control, and automated shutdown profile management. This universal controller handles all these functions through programmable logic, avoiding the need for separate control devices for each function and managing complexity through integration.
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 precise control of air flowrate and noise levels, improving comfort by adjusting humidity and temperature, reducing energy consumption, and enhancing air filtration, while allowing for customizable settings to suit different HVAC system configurations and operational modes.
Implementation Method 1
the blower drive motor is a variable speed type and the operating speed may be selected by a pulse width modulated (PWM) electrical signal from a thermostat or controller
Data Source
AI summary
An HVAC system includes a variable speed electric motor driven fan for circulating air to an enclosed space through an indoor unit for providing heating or cooling effect to air circulated through the indoor unit. A controller with user or system installer actuatable switches includes a programmable microcontroller providing a pulse width modulated (PWM) signal to a motor control unit to select a predetermined air flowrate less than full air flowrate during system startup and shutdown. User input parameters include selected percentages of full air flowrate to satisfy requirements for reduced noise level, lower humidity and for improved sensible heating of air being circulated, the latter being effective particularly for heat pump applications. Selection of pre-run, short run and shutdown cycles may be provided.