Ventilation Heating Control with Variable AC Power Modulation
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Solution Overview
Problem
Conventional ventilation systems with resistive heating elements face limitations in continuously regulating temperature due to step-wise adjustment of heating capacity, which fails to accurately match fluctuating demands and increases system complexity and cost.
Innovation Solution
A ventilation system utilizing a variable frequency drive (VFD) or matrix drive to provide a controlled, continuously variable AC voltage/current to resistive heating elements, allowing for continuous temperature regulation by modulating power supply based on target values and real-time monitoring of heating capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If step-wise adjustment of heating capacity is used with fuses and relays, then heating capacity can be adjusted in discrete steps, but continuous temperature control and fine tuning are limited
Solution Approach 1:
The patent changes the control parameter from discrete on/off switching of heating elements to continuous phase angle control of AC power delivery. By varying the phase angle of the AC waveform supplied to the resistive heating element, the heating capacity can be continuously adjusted without changing the physical configuration of heating elements, thereby achieving fine temperature tuning with minimal components.
Solution Approach 2:
The patent replaces the mechanical/electrical switching system (fuses and relays) with an electronic phase control system. Instead of physically connecting or disconnectating heating elements through relays, the system uses electronic phase angle control to modulate power delivery, eliminating the need for multiple relays and fuses while enabling continuous adjustment.
2Adaptability or versatility
If more temperature adjustment options are provided, then fine tuning capability is improved, but system size, cost and complexity increase
Solution Approach 1:
The patent makes a single resistive heating element serve multiple heating capacity functions through phase angle control. Instead of requiring multiple heating elements or complex switching arrangements to provide different heating levels, the system uses one universal heating element that can deliver any heating capacity from minimum to maximum by adjusting the phase angle, thereby providing unlimited temperature adjustment options without increasing system size.
3Productivity
If conventional step-wise heating control is used, then system simplicity is maintained, but accurate matching to fluctuating demands is failed
Solution Approach 1:
The patent implements a feedback control system where a temperature sensor continuously monitors the actual temperature and compares it with the target temperature. Based on this feedback, the phase angle control is dynamically adjusted to match the heating output to the actual temperature deviation, enabling accurate tracking of fluctuating temperature demands and optimizing energy efficiency through precise control.
Solution Approach 2:
The patent transitions from static, step-wise heating control to dynamic, continuous phase angle control. The system can rapidly and smoothly adjust the heating capacity in real-time according to changing temperature demands, providing continuous adaptability rather than discrete steps, thereby accurately matching fluctuating thermal loads.
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 cost-effective, continuous, and precise temperature control, reducing energy costs and simplifying the temperature control unit by allowing step-less adjustment of heating capacity, while also regulating motor speed, thus optimizing process control.
Implementation Method 1
resistive heating elements, such as electrically conductive wires or foils, which are connected to an electrical supply... As electricity passes through said resistive heat elements, some energy is lost as heat due to the resistance of said elements
Data Source
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AI summary
Ventilation system (10) comprising resistive heating means (12) for heating gas flowing through the ventilation system (10) and means that are arranged to provide a 5 controlled, continuously variable AC voltage/current to at least part of the resistive heating means (12) of the ventilation system (10) to modulate the power (24) being supplied thereto and to enable continuous regulation of the temperature of gas flowing through the ventilation system (10).