Indoor Fan Pressure Estimation for Sensorless Airflow Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional air-conditioning apparatuses require complex system design and increased costs due to the need for interconnected control of fan control, damper control, and static-pressure detection, limiting their ability to perform independent control operations.
Innovation Solution
An air-conditioning apparatus that calculates external static pressure and airflow without using a static-pressure detector, allowing for independent control of the indoor-unit-side fan based on these values, thereby simplifying design and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a static-pressure detector is installed in the duct to detect external static pressure, then the accuracy of static pressure measurement is improved, but the device complexity and cost increase
Solution Approach 1:
The patent extracts the static pressure detection function from a dedicated static-pressure detector and relocates it to the control unit. The control unit calculates external static pressure using the relationship between airflow rate and power consumption, eliminating the need for a separate detection device and reducing system complexity while maintaining measurement capability
Solution Approach 2:
The patent replaces the mechanical static-pressure detector with a calculation-based approach. Instead of physically detecting static pressure, the system uses electrical power consumption data and airflow rate measurements to compute the external static pressure value, substituting mechanical detection with computational methods
2Reliability
If interconnected control of fan control, damper control, and static-pressure detection is implemented, then the overall system control performance is improved, but the device complexity and cost increase
Solution Approach 1:
The patent merges the static pressure detection function with the control unit, combining multiple control functions (fan control, damper control, and static pressure monitoring) into a single integrated system. This consolidation maintains comprehensive control capability while reducing the number of separate components and simplifying the overall control architecture
Solution Approach 2:
The control unit is designed to perform multiple functions: it controls the fan motor, manages damper positions, calculates external static pressure, and coordinates overall system operation. This multi-functional approach eliminates the need for dedicated separate control systems for each function, reducing complexity while maintaining reliable interconnected control
Data Source
Figure 1~2
Figure 3~4(b)
Figure 5(a)~5(b)
AI summary
Provided is an easy-to-design, inexpensive air-conditioning apparatus in which an external static pressure and an airflow are calculated without using a static-pressure detector and an indoor-unit-side fan is controlled using those values. An air-conditioning apparatus 100 according to the present invention is configured such that a control unit (indoor-unit-side control unit 24) stores an external static pressure of an indoor unit 1 calculated from a rotation speed of an indoor-unit-side fan 22 when the airflow of the indoor-unit-side fan 22 is controlled to a predetermined rated airflow and controls the rotation of the indoor-unit-side fan 22 so that the external static pressure of the indoor unit 1 obtained thereafter from the rotation speed of the indoor-unit-side fan 22 approaches the stored external static pressure.