Indoor Unit Heat Exchanger Layout for Dew Water Control
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Solution Overview
Problem
The existing indoor air-conditioning units with fin-and-tube-type heat exchangers disposed over parallel flow type heat exchangers result in increased thickness, leading to a larger size and potential dew water entry issues.
Innovation Solution
The design incorporates a main heat exchanger unit with vertically extending heat-transfer pipes and a sub heat exchanger unit with heat-transfer pipes extending in the width direction, where the leeward-side sub heat exchanger covers part of the upper portion of the main heat exchanger, reducing unit size and preventing dew water entry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fin-and-tube-type heat exchanger is disposed over the entirety of the parallel flow type heat exchanger, then dew water can be prevented from entering the air passage, but the thickness of the heat exchanger increases, resulting in an increase in the thickness (depth) of the indoor unit
Solution Approach 1:
The sub heat exchanger unit is divided into a leeward-side first sub heat exchanger and a leeward-side second sub heat exchanger. The leeward-side second sub heat exchanger has a lower end surface located above the air passage wall, creating a segmented configuration that prevents dew water from entering the air passage while reducing the overall thickness of the indoor unit compared to a continuous fin-and-tube heat exchanger covering the entire parallel flow heat exchanger.
2Temperature
If the sub heat exchanger unit is disposed to cover the main heat exchanger unit, then heat transfer performance is enhanced, but the device complexity increases
Solution Approach 1:
The leeward-side second sub heat exchanger is disposed to cover a part of the upper portion of the second main heat exchanger, creating a nested configuration where the sub heat exchanger unit is partially positioned over the main heat exchanger unit. This nesting arrangement enhances heat transfer performance by providing additional heat exchange surface area while maintaining a relatively simple overall structure compared to fully separate heat exchanger units.
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 a reduced size of the indoor unit while effectively preventing dew water from entering the air passage, enhancing heat transfer performance and maintaining efficient refrigerant flow.
Implementation Method 1
a main heat exchanger unit provided to cover the air-sending fan and configured to exchange heat between refrigerant and air
Implementation Method 2
Defrost water or dew condensation water generated in the parallel flow type heat exchanger moves to the fin-and-tube-type heat exchanger due to the gravity and is drained
Data Source
AI summary
An indoor unit for an air-conditioning apparatus includes a main heat exchanger unit and a sub heat exchanger unit, the main heat exchanger unit includes a first main heat exchanger disposed at a front side of a case and a first heat-transfer pipe extending in a vertical direction, and a second main heat exchanger disposed at a back side of the case and a second heat-transfer pipe extending in the vertical direction. The sub heat exchanger unit includes a leeward-side first sub heat exchanger disposed at a leeward side of the first main heat exchanger and a heat-transfer pipe extending in a width direction, and a leeward-side second sub heat exchanger including a heat-transfer pipe extending in the width direction. The leeward-side second sub heat exchanger has a lower end surface located above an air passage wall and is disposed at a leeward side of the second main heat exchanger.