Parallel fan powered terminal unit
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Solution Overview
Problem
Conventional parallel fan powered terminal units face challenges with heating coil placement, as it either impedes air flow or damages the fan, and is difficult to access for maintenance in existing designs.
Innovation Solution
A parallel fan unit design with a heating coil placed in the induced air chamber, removable without disassembling the chamber, where the fan blows secondary air through the coil to heat it, and a controller manages airflow and heating coil operation based on thermostat feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the heating coil is placed in front of the primary and secondary air flow, then the heating coil can heat the air before it enters the region, but the heating coil impedes the air flow and increases the load of the air handling unit
Solution Approach 1:
The patent divides the air handling system into separate primary air and secondary air pathways. The heating coil is specifically assigned to heat only the secondary air that is drawn from the ceiling plenum, while the primary air from the air handling unit remains unheated. This segmentation allows the heating function to be isolated to a specific zone (secondary air chamber) without impeding the main primary air flow through the air handling unit, thus resolving the contradiction between heating effectiveness and air flow efficiency.
2Temperature
If the heating coil is placed behind the secondary air flow to heat the secondary air, then the secondary air can be heated, but the heat generated by the heating coil may cause damage to the fan that draws the secondary air
Solution Approach 1:
The patent extracts the heating coil from the fan housing and relocates it to a separate secondary air chamber. The secondary air is drawn through a dedicated inlet from the ceiling plenum, heated in this separate chamber, and then mixed with primary air before being delivered to the region. This extraction of the heating function from the fan assembly eliminates the risk of heat damage to the fan while maintaining the ability to heat secondary air effectively.
3Temperature
If the heating coil is placed in the duct in front of the fan, then the heating coil can be positioned for heating, but it is difficult to access and/or service
Solution Approach 1:
The patent segments the terminal unit into modular components with the heating coil housed in a dedicated secondary air chamber that is accessible from the front service panel. This modular segmentation allows the heating coil to be independently accessed, removed, or serviced without disassembling the entire terminal unit or ductwork, thereby improving maintenance accessibility while maintaining effective heating function.
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 design enhances airflow efficiency by avoiding increased load on the air handling unit and allows for easier maintenance of the heating coil, while effectively controlling temperature in regions by adjusting airflow and heating coil activation.
Implementation Method 1
the heating coil heats the secondary air
Implementation Method 2
a fan disposed in the induced air chamber, wherein the fan is configured to blow the secondary air received via the induced air chamber toward the heating coil
Data Source
AI summary
Aspects of the present disclosure include a primary air chamber configured to receive primary air, an induced air chamber configured to receive secondary air, a heating coil disposed in the induced air chamber, wherein the heating coil is removable from the induced air chamber without disassembling at least a portion of the induced air chamber, and the heating coil does not receive the primary air, a fan disposed in the induced air chamber, wherein the fan is configured to blow the secondary air received via the induced air chamber toward the heating coil and the heating coil heats the secondary air.