Fireplace Room Ventilation Control for Negative Pressure Prevention

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Solution Overview

Problem

Existing ventilation systems with fireplaces face challenges in maintaining positive air pressure to prevent toxic smoke gases from entering the room, requiring additional costly installation and equipment for air pressure monitoring.

Innovation Solution

Integrating air pressure control and monitoring within the ventilation system's control device, using model-based pressure monitoring and air resistance monitoring to ensure supply air flow exceeds exhaust air flow, and incorporating redundant control units for reliable operation without external air pressure monitors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional air pressure monitors and equipment are installed to monitor air pressure, then air pressure monitoring reliability is improved, but installation costs and device complexity increase

Engineering Contradiction:
Improveair pressure monitoring reliabilityVSAvoidinstallation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines air pressure monitoring functionality with the existing ventilation system control device. The control device integrates a monitoring unit that uses characteristic data from supply and exhaust fans to determine air pressure conditions, eliminating the need for separate air pressure monitors and reducing installation complexity while maintaining monitoring reliability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The ventilation system's control device performs self-monitoring of air pressure conditions by evaluating fan characteristic data. The system uses its own operational parameters (fan speeds, power consumption) to infer air pressure status, making the system self-sufficient and eliminating dependency on external monitoring equipment

Inventive Principle:
Principle #25Self-service

2Reliability

If fan speeds are increased to maintain positive air pressure, then air pressure control reliability is improved, but energy consumption increases

Engineering Contradiction:
Improveair pressure control reliabilityVSAvoidfan energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The control device dynamically adjusts fan speeds based on real-time monitoring of characteristic data and determined air pressure conditions. Rather than maintaining constant high speeds, the system optimizes fan operation to maintain positive air pressure only when necessary, reducing overall energy consumption while ensuring reliability when needed

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements feedback control by continuously monitoring fan characteristic data, determining air pressure conditions, and adjusting fan speeds accordingly. This closed-loop control ensures positive air pressure is maintained reliably while minimizing energy consumption by adjusting speeds based on actual conditions rather than operating at maximum speed continuously

Inventive Principle:
Principle #23Feedback

3Device complexity

If monitoring is based solely on fan characteristic data, then device complexity is reduced, but measurement precision may deteriorate

Engineering Contradiction:
Improvemonitoring system complexityVSAvoidair pressure measurement precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces direct mechanical air pressure measurement devices with an indirect monitoring approach using electrical characteristic data from fans. By analyzing power consumption, current, and speed data, the system infers air pressure conditions without physical pressure sensors, simplifying the system while providing sufficient precision for safety control

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system uses fan characteristic data as an intermediary to indirectly determine air pressure conditions. Rather than measuring pressure directly, the monitoring unit analyzes intermediate parameters (power consumption, current, speed) that correlate with air pressure status, providing a simplified yet effective measurement approach

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2317235B1Method and safety device for controlling the air pressure in a room with a fireplace
Publication Date: 2013.12.11 DIMPLEX LUFTUNGSSYST ZWEIGNIEDERLASSUNG DER APPLIED ENERGY PROD
  • EP2317235B1 patent drawingFigure 1~2

AI summary

In order to reliably create a negative pressure with little effort in a room (2) with a fireplace that depends on the room air and a ventilation system, it is provided that a ventilation system control device (20) controls a fan (10) on the supply air side and a fan (12) on the exhaust air side in such a way be controlled that a supply air flow (Z) ≥ an exhaust air flow (A). In addition, the control device (20) is also provided for monitoring this and has a monitoring unit (24) which uses characteristics of the fans (10, 12) to monitor them for a malfunction to determine whether the supply air flow (Z) ≥ the exhaust air flow (A ) is.