Dual-Pass Airflow Coil Layout for Outside Air Conditioning

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Solution Overview

Problem

Conventional air conditioning units are not suitable for conditioning outside air due to differences in humidity and temperature between return and outside air, leading to slower face velocity through cooling coils, which can cause freezing and require costly replacements.

Innovation Solution

A dual pass air conditioning device configuration with a pre-conditioned, partially-conditioned, and post-conditioned air passage chamber, where air passes through the cooling coil system twice, allowing the same coil and blower system used in return air units to condition outside air without needing replacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional return air conditioning units are used to condition outside air, then the existing cooling coil system can be utilized, but the face velocity through the cooling coil becomes too slow causing the coils to freeze

Engineering Contradiction:

Improvereuse of existing cooling coil systemVSAvoidcooling coil freezing

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The air passage is divided into multiple segments with partition walls, creating separate flow paths that guide air through the cooling coil system in a controlled manner. This segmentation allows maintenance of appropriate face velocity while using the existing coil system.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The air flow path is extended by creating a multi-dimensional passage structure with partitions, effectively increasing the path length and controlling velocity distribution without changing the cooling coil system itself.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Temperature

If the face velocity through the cooling coil is reduced to cool outside air, then the air can be conditioned to desired temperature, but the cooling coils freeze due to insufficient heat transfer

Engineering Contradiction:

Improveair temperature reductionVSAvoidcoil freezing

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

Air is pre-conditioned in a dedicated chamber before entering the cooling coil system, removing excess humidity and reducing the cooling load. This preliminary action allows the coil to operate at higher face velocities without freezing while still achieving the desired temperature reduction.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A pre-conditioning chamber acts as an intermediary between the outside air intake and the cooling coil system, preparing the air by removing humidity and reducing temperature partially before the air reaches the coil, thereby preventing coil freezing.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If return air conditioning units are used for outside air conditioning, then equipment costs are reduced, but the different properties of outside air (higher humidity and temperature) cause operational problems

Engineering Contradiction:

Improveequipment cost reductionVSAvoidadaptation to outside air conditions

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The air conditioning unit is designed with a universal air passage structure that can handle both return air and outside air conditions. The pre-conditioning chamber and partitioned passages enable the same equipment to adapt to the different properties of outside air without requiring specialized components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system changes the parameters of outside air (temperature and humidity) through the pre-conditioning chamber before the air enters the cooling coil system, transforming it into a state that is compatible with the existing return air conditioning equipment.

Inventive Principle:

Principle #35Parameter changes

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

Enables efficient conditioning of outside air using existing return air conditioning unit components, preventing coil freezing and reducing operational expenses by maintaining consistent air flow and heat transfer.

Implementation Method 1

The cooling coil system is configured to receive air from the pre-conditioned air passage chamber and to condition the air as it passes into the partially-conditioned air passage chamber

Methodology Applied

Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 2

An impermeable partition separates the pre-conditioned air passage chamber and the post-conditioned air passage chamber

Methodology Applied

Scientific EffectPhysical separation: Physical Containment

Data Source

PatentUS9057553B1Dual pass air conditioning unit

Publication Date: 2015.06.16 MJC

AI summary

Apparatus and methods provide for a dual pass air flow configuration in an air conditioning system to improve efficiency and performance of the air conditioning system. An air conditioning device includes a pre-conditioned air passage chamber separated from a post-conditioned air passage chamber by an impermeable partition. A coil system separates the pre-conditioned air passage chamber and the post-conditioned air passage chamber from a partially-conditioned air passage chamber. The coil system is configured to receive air from the pre-conditioned air passage chamber and to condition the air passing through the coil system into the partially-conditioned air passage chamber. The coil system is also configured to receive the air from the partially-conditioned air and further condition the air as it passes through the coil system into the post-conditioned air passage chamber.