Parallel Blower Speed Ratio Control for Minimum Power Consumption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
HVAC systems with parallel connected fans/blowers face challenges in optimizing energy efficiency due to varying speed combinations, leading to increased power consumption.
Innovation Solution
A system and method that includes a controller to calculate and adjust the blower speed ratio between two blowers connected in parallel to achieve the required total air flow at minimum power consumption, utilizing motor drives and performance specifications to optimize operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple blowers are operated at high speeds to meet desired total flow, then air flow requirement is satisfied, but power consumption increases significantly
Solution Approach 1:
The system changes the operating parameters (speeds) of the blowers dynamically. Instead of operating all blowers at high speeds, the controller adjusts individual blower speeds to different values that collectively meet the total flow requirement while minimizing total power consumption. This is achieved by accessing blower performance specifications and calculating optimal speed combinations.
Solution Approach 2:
The system implements dynamic speed control of blowers based on real-time conditions. The controller continuously monitors the controlled variable and adjusts blower speeds dynamically rather than maintaining fixed high speeds, allowing the system to adapt to varying flow requirements and minimize energy consumption at each operating point.
2Use of energy by moving object
If blower speeds are reduced to minimize power consumption, then energy efficiency improves, but total air flow may not meet the desired requirement
Solution Approach 1:
The system utilizes blower performance specifications (curves) that define the relationship between speed, flow, and power consumption. By changing speed parameters and referencing these performance characteristics, the controller identifies the optimal operating point where the desired total flow is achieved at minimum power consumption, rather than simply reducing speeds arbitrarily.
Solution Approach 2:
The controller receives feedback on the controlled variable (which reflects the total flow requirement) and uses this information to adjust blower speeds. The system continuously monitors whether the flow requirement is met and dynamically adjusts speeds to maintain the desired flow while minimizing power consumption, ensuring both flow and energy efficiency requirements are satisfied.
3Device complexity
If identical blowers are used in parallel, then system simplicity is maintained, but flexibility to optimize power consumption is limited
Solution Approach 1:
The system segments the total flow requirement among multiple blowers, allowing each blower to operate at potentially different speeds. Even with identical blowers, the controller can assign different speed values to each blower based on performance specifications and real-time requirements, enabling flexible optimization of power consumption without changing the physical blower configuration.
Solution Approach 2:
The system introduces dynamic control capability to identical blowers, allowing their speeds to be independently adjusted. This dynamic control transforms static, uniform blower operation into flexible, optimized operation where each blower's speed can be tailored to minimize total power consumption while meeting the collective flow requirement.
Data Source
AI summary
A ventilation system includes first and second blowers connected to a plenum in parallel, with a first motor drive to control a speed of an electric motor of the first blower and a second motor drive to control a speed of an electric motor of the second blower. A controller associated with the first blower is programmed to receive a set point for a controlled variable that is controllable by operation of the first and second blowers, estimate a total air flow required from the first and second blowers to reach the controlled variable set point, calculate a blower speed ratio between a first blower speed and a second blower speed that provides the required total air flow at a minimum power consumption level, and generate commands to cause the first blower and the second blower to operate at speeds resulting in the calculated blower speed ratio.