Automatic blower control
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Solution Overview
Problem
Commissioning HVAC systems with variable air volume (VAV) systems is laborious and costly due to the need for manual customization of blower motor speeds to achieve desired airflow rates, requiring trained technicians and significant time and resources, especially in large buildings with multiple units.
Innovation Solution
A blower unit controller that employs a mathematical model to relate motor speed to airflow parameters, allowing for pre-configuration or remote configuration of HVAC systems, eliminating the need for on-site customization by using an inverter to provide motor speed control signals based on stored airflow models, thereby simplifying the commissioning process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manual customization of blower motor speeds is performed to achieve desired airflow rates, then airflow precision is improved, but commissioning time and labor costs increase
Solution Approach 1:
The system performs preliminary configuration by storing multiple pre-determined blower motor speed settings in the controller memory before commissioning. Each speed setting corresponds to a specific airflow rate requirement. During commissioning, the technician simply selects the appropriate pre-configured speed setting rather than manually adjusting the motor speed, thereby achieving precise airflow control without time-consuming manual customization.
Solution Approach 2:
The system changes the control parameter from manual motor speed adjustment to selection of pre-stored speed settings. The controller contains multiple predetermined speed values that can be quickly selected based on the required airflow rate, transforming the commissioning process from a manual tuning task to a simple parameter selection task that maintains precision while reducing time.
2Manufacturing precision
If manual customization of blower motor speeds is performed to achieve desired airflow rates, then airflow precision is improved, but labor costs and complexity increase
Solution Approach 1:
The controller is equipped with self-service capabilities by storing multiple pre-determined blower motor speed settings internally. The system serves itself by providing ready-to-use speed configurations that eliminate the need for external expert intervention. During commissioning, the technician acts as a simple selector rather than an expert tuner, dramatically reducing labor costs and commissioning complexity while maintaining airflow precision.
3Manufacturing precision
If direct measurement of motor speed or airstream is implemented, then airflow control precision is improved, but system complexity and cost increase
Solution Approach 1:
Instead of directly measuring motor speed or airstream with sensors and measurement devices, the system uses a copied approach by storing pre-determined speed settings that represent the desired airflow conditions. The controller selects from these pre-configured speed values based on the required airflow rate, achieving accurate airflow control without the complexity and cost of direct measurement instrumentation.
Data Source
AI summary
A blower unit controller and an HVAC system are disclosed herein. In one embodiment, the blower unit controller includes: (1) an input configured to receive motor operating parameters, (2) an output configured to provide a motor speed control signal to an inverter, (3) a memory configured to store a mathematical model of airflow produced by a blower motor, the mathematical model being configured to relate a motor speed to the motor operating parameters and (4) a processor configured to produce the speed control signal based on the mathematical model.