Energy Recovery Ventilation With PWM DC Fan Airflow Balancing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current energy recovery ventilators face limitations due to AC fans, which result in limited speed control, noise, vibration, reduced energy efficiency, and unbalanced airflows leading to suboptimal energy transfer and ventilation efficiency, as well as a lack of real-time data for optimized control.
Innovation Solution
A ventilation system utilizing direct current (DC) fans with pulse width modulation for continuous speed control, temperature and humidity sensors to optimize airflow balance, and an energy exchange core for efficient energy transfer, allowing for real-time adjustments to ensure balanced and efficient airflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If AC fans with traditional speed control methods (tapped transformers, triacs, capacitors) are used, then the ventilation system can operate, but the fan speeds are limited to a low number of discrete levels resulting in lower ventilation efficiency
Solution Approach 1:
The patent replaces traditional mechanical/electrical speed control methods (tapped transformers, triacs, capacitors, induction coils) with DC motor technology. DC fans provide continuous variable speed control through pulse width modulation (PWM), eliminating the discrete speed levels inherent in AC motor control and thereby improving ventilation efficiency while maintaining manageable system complexity
Solution Approach 2:
The patent implements dynamic speed control of DC fans using PWM technology, allowing the fan speeds to be continuously adjusted rather than fixed at discrete levels. This dynamic control enables optimization of airflow rates for different operating conditions, directly improving ventilation efficiency
2Object-affected harmful factors
If AC fans with traditional speed control methods are used, then the ventilation system can operate, but excessive noise and vibration occur due to harmonics
Solution Approach 1:
The patent substitutes AC motor technology with DC motor technology for fan drive. DC motors operate without the harmonic distortions inherent in AC motor control methods (triacs, tapped transformers), thereby eliminating excessive noise and vibration while maintaining or improving energy efficiency through precise PWM control
3Use of energy by moving object
If traditional AC fan systems are used, then the ventilation system can operate, but energy efficiency is reduced
Solution Approach 1:
The patent employs dynamic PWM control of DC fan motors, enabling continuous adjustment of fan speeds to match actual ventilation requirements. This dynamic control optimizes energy consumption by running fans at the minimum necessary speed while maintaining adequate airflow, thereby improving both energy efficiency and ventilation effectiveness
Solution Approach 2:
The patent incorporates temperature sensors that provide feedback to the control system. This feedback enables the system to adjust DC fan speeds in response to actual thermal conditions, optimizing energy efficiency by reducing fan power consumption when full ventilation capacity is not required while maintaining appropriate ventilation efficiency
4Extent of automation
If no real-time sensor data is used, then the ventilation system is simpler, but automated optimized control based on environmental conditions cannot be achieved
Solution Approach 1:
The patent incorporates temperature sensors positioned in supply and exhaust airflows that provide real-time feedback to the control system. This feedback enables automated adjustment of DC fan speeds based on actual environmental conditions, achieving optimized control while adding only moderate system complexity through straightforward sensor-integratorator-controller architecture
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 system achieves improved energy efficiency, balanced airflows, and optimized ventilation performance by using DC fans with fine speed control and sensor data for dynamic adjustments, reducing energy consumption and operational costs while maintaining air quality.
Implementation Method 1
The supply airflow and the exhaust airflow undergoing an energy exchange in the ventilator. Preferably, the energy exchange core is a heat exchange core.
Implementation Method 2
A first direct current (DC) fan draws air from an exterior of a building for circulation into an interior of the building, and produces a supply airflow through the ventilator. A second DC fan draws a return air from the interior of the building for exhausting to the exterior of the building, and produces an exhaust airflow through the ventilator enclosure.
Data Source
AI summary
An energy recovery ventilation system is described which allows for continuous fan speed control through pulse width modulation of direct current fans. The energy recovery ventilation described is capable of fine motor speed control without the disadvantages of high noise, low efficiency and a fixed number of speeds present in commonly-used speed-varying techniques used with alternating current (AC) fans. This may be accomplished through the use of direct current (DC) fans and pulse width modulation. A controller is used to optimize the ventilation and energy efficiency of the system through the use of several temperature sensors. The energy recovery ventilation also provides a control process for self-optimization of the energy recovery ventilation, in case the supply and exhaust airflows are unequal. An unbalance may be detected by calculating the thermal efficiencies of the exhaust and supply airflows.