Indoor unit for air conditioning device

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Solution Overview

Problem

Existing indoor heat exchangers in air conditioning devices face challenges in achieving a balance between heating and cooling capacities, with heating performance being enhanced by counter flow configurations but cooling performance being compromised due to low air velocity regions leading to inadequate heat transfer.

Innovation Solution

The indoor heat exchanger is designed with distinct regions: a high-velocity first region forming full counter flow during heating and partial counter/partial parallel flows during cooling, and a low-velocity second region with partial counter and parallel flows, optimizing refrigerant paths to maintain effective heat transfer across both operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If refrigerant flows through all tube lines sequentially during cooling operation, then a full parallel flow portion is formed, but cooling performance deteriorates due to decreased temperature difference between refrigerant and air

Engineering Contradiction:

Improvecooling capacityVSAvoidtemperature difference between refrigerant and air

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The refrigerant flow paths are segmented into multiple tube lines with different connection configurations. The second tube line is connected to both the first and third tube lines, creating a structure where complete sequential flow through all tube lines is prevented, thereby avoiding full parallel flow and maintaining temperature difference during cooling operation

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of allowing refrigerant to flow sequentially through all tube lines in the same direction (which creates parallel flow), the invention uses a configuration where the second tube line connects to both upstream and downstream tube lines, effectively inverting the expected flow pattern and preventing complete parallel flow alignment

Inventive Principle:

Principle #13The other way round (Inversion)

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 ensures high heating capacity and improved cooling performance by maintaining temperature differences and reducing pressure loss, thereby enhancing overall heat exchanger effectiveness and efficiency.

Implementation Method 1

the refrigerant dissipates heat into indoor air and then is condensed

Methodology Applied

Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 2

air carried by the indoor fan passes through the indoor heat exchanger

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 3

the refrigerant dissipates heat into indoor air and then is condensed

Methodology Applied

Scientific EffectCondensation: Condensation

Implementation Method 4

the refrigerant absorbs heat from the indoor air, and then is evaporated

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS9568221B2Indoor unit for air conditioning device

Publication Date: 2017.02.14 DAIKIN INDUSTRIES LTD

AI summary

An indoor heat exchanger has a first region including a first refrigerant path and a second region including a second refrigerant path. The first refrigerant path forms a full counter flow portion during a heating operation, and forms a full parallel flow portion during a cooling operation. The second region is configured so that air has a lower flow velocity in the second region than in the first region. During both the cooling and heating operations, the second refrigerant path forms both a partial parallel flow portion and a partial counter flow portion.