Complex Heat Source Apparatus Fan Downsizing
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Solution Overview
Problem
Existing complex heat source apparatuses with common air-fuel mixture supply for multiple burners suffer from reduced thermal efficiency and increased fan noise due to unnecessary air flow when only one burner is operational, requiring larger fans for simultaneous operation.
Innovation Solution
A complex heat source apparatus with totally aerated combustion burners, a single fan for air-fuel mixture supply, and on-off valves to control air-fuel mixture distribution, ensuring maximum supply to the first burner while reducing supply to the second burner during simultaneous operation, along with intermittent combustion control to manage combustion levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common fan supplies air-fuel mixture to multiple burners, then device complexity is reduced, but thermal efficiency deteriorates when only one burner operates due to unnecessary air flow cooling the heat exchanger
Solution Approach 1:
The patent divides the air-fuel mixture supply system into separate controllable branches for each burner. Each burner has its own flow control valve that can independently regulate or stop air-fuel mixture flow, allowing the system to segment the common supply into discrete controllable paths that can be activated or deactivated based on operational needs.
Solution Approach 2:
The patent introduces dynamic control through flow control valves that adjust the air-fuel mixture flow rate to each burner based on operational conditions. This dynamic adjustment allows the system to optimize performance by providing full flow when needed and reducing or stopping flow when burners are not in use, preventing energy loss while maintaining operational flexibility.
2Productivity
If maximum air-fuel mixture supply is provided to all burners during simultaneous operation, then combustion performance is improved, but fan size and noise increase
Solution Approach 1:
The patent applies local quality by providing different air-fuel mixture flow rates to different burners based on their individual requirements and positions. The flow control valves enable each burner to receive appropriate flow locally, with the first burner receiving maximum flow and the second burner receiving reduced flow, optimizing combustion performance while reducing overall fan load and noise.
Solution Approach 2:
The patent changes the flow rate parameter of air-fuel mixture supplied to each burner through flow control valves. By adjusting these parameters dynamically - providing maximum flow to the first burner and reduced flow to the second burner during simultaneous operation - the system achieves optimal combustion capacity while reducing the total flow requirement and associated fan noise.
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
This configuration allows for downsizing of the fan, reducing noise and maintaining efficient combustion levels by optimizing air-fuel mixture distribution and controlling combustion amounts, thereby preventing reduced turndown ratios.
Implementation Method 1
both the first and the second burners being constituted by totally aerated combustion burners
Implementation Method 2
a first burner for heating the first heat exchanger; and a second burner for heating the second heat exchanger
Data Source
Figure 1
Figure 2
AI summary
In a complex heat source apparatus having first and second, i.e., a total of two, burners (21, 22), and a fan (6) is interposed in an air supply passage (5) connected to both the burners. Downstream end of a gas supply passage (7) having interposed therein a flow control means (73) is connected to that portion of the air supply passage which is on an upstream side or a downstream side of the fan (6). It is thus so arranged that air-fuel mixture of the primary air and the fuel gas is supplied to both the burners (21, 22) through the air supply passage (5). Downsizing of the fan (6) and the reduction of noises can be attained at the time of simultaneous operation in which both the first and the second burners (21, 22) are combusted. An on-off valve (81, 82) is respectively disposed at a connection portion (521) between the first burner 21 and the air supply passage (5) and at a connection portion (522) between the second burner (22) and the air supply passage (5). The air flow resistance in the connection portion (522) between the second burner (22) and the air supply passage (5) is set, in a state in which the amount of air-fuel mixture supplied to the first burner (21) at the time of simultaneous operation becomes maximum corresponding to a rated combustion amount of the first burner (21), to be such that the amount of air-fuel mixture supplied to the second burner (22) becomes smaller than a maximum amount corresponding to a rated combustion amount of the second burner (22).