Radiant Tube Heater Air Preheating for Compact Heat Recovery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gas fired radiant tube heaters face a trade-off between high radiant heat efficiency and overall thermal efficiency, with high radiant efficiency often resulting in reduced overall thermal efficiency and a larger, less compact design.
Innovation Solution
A radiant tube heater design incorporating a burner assembly with a pre-mixer chamber, a combustion air pre-heater using residual sensible heat, and a secondary air channel, along with a cross-flow type heat exchanger block configuration, to enhance air and fuel mixing and preheat combustion air, promoting both high radiant and thermal efficiency while maintaining a compact size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high radiant efficiency heater design is implemented, then radiant heat efficiency is improved, but overall thermal efficiency is reduced
Solution Approach 1:
Combustion air is preheated before entering the burner assembly using heat exchangers that recover thermal energy from exhaust gases. This preliminary heating action reduces the energy required for combustion while maintaining high radiant efficiency, thereby improving overall thermal efficiency without sacrificing the primary function.
Solution Approach 2:
Thermal energy from exhaust gases that would normally be discarded is recovered through heat exchangers to preheat combustion air. This recovery process converts waste energy into useful thermal energy, improving overall thermal efficiency while preserving the high radiant heat output of the heater.
2Use of energy by moving object
If high radiant efficiency heater design is implemented, then radiant heat efficiency is improved, but device size increases
Solution Approach 1:
The heat exchangers are positioned within or around the radiant tube assembly, nesting the heat recovery function within the existing structural envelope. This allows the heater to maintain compact dimensions while incorporating the additional functionality needed for high radiant efficiency and thermal recovery.
Solution Approach 2:
The heat exchangers are arranged in a compact configuration around the radiant tubes, utilizing three-dimensional space efficiently. By positioning heat exchange surfaces in multiple dimensions around the combustion chamber, the design achieves effective heat recovery without increasing the overall footprint or volume of the heater unit.
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
The solution achieves a higher radiant efficiency while maintaining good overall thermal efficiency and a compact design, effectively directing radiant heat downward and reducing energy losses through optimized heat exchanger and reflector configurations.
Implementation Method 1
at least part of the combustion air supplied to said plenum is preheated in said air pre-heater using residual sensible heat of the hot combustion gas products of the heater
Implementation Method 2
preheated in said air pre-heater using residual sensible heat of the hot combustion gas products
Implementation Method 3
air is mixed with burner fuel entering said pre-mixer through said nozzle prior to being combusted at a burner head
Implementation Method 4
being combusted at a burner head
Implementation Method 5
Gas fired radiant tube heaters are widely used especially to heat industrial and commercial premises
Data Source
AI summary
A radiant tube heater with a burner assembly, a radiant tube assembly and a combustion air pre-heater; wherein the burner assembly comprises: a burner fuel nozzle; a plenum chamber and a pre-mixer chamber; the plenum chamber having a combustion air inlet; wherein in use: combustion air flows from said plenum chamber through an orifice to said pre-mixer where said air is mixed with burner fuel entering said pre-mixer through said nozzle prior to being combusted at a burner head; said pre-mixer being at least partly located within said radiant tube assembly; and where in use at least part of the combustion air supplied to said plenum is preheated in said air pre-heater using residual sensible heat of the hot combustion gas products of the heater.