Indoor Fan Threshold Control for Cold-Air-Free Heating Startup

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Air conditioners that perform heating through a vapor compression refrigeration cycle often blow out cold air initially, causing discomfort and slowing room temperature rise, as they restrict air volume to prevent cold air from reaching users.

Innovation Solution

The air conditioner implements a dual cold air reduction control system, restricting air volume until the indoor heat exchanger reaches a certain temperature and then increasing it, allowing for selective reduction of cold air discomfort or promotion of room temperature rise based on preset conditions, including flap orientations and temperature thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the air volume of the indoor fan is restricted until the indoor heat exchanger reaches a high temperature, then user discomfort from cold air is reduced, but the room temperature rise is slowed

Engineering Contradiction:
Improvecold air discomfortVSAvoidroom temperature rise time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent applies parameter changes by introducing two different temperature thresholds (first temperature and second temperature) to control the fan air volume at different stages. The control parameter (air volume restriction) is adjusted based on the heat exchanger temperature reaching different threshold values, enabling dynamic adaptation to system state changes and resolving the contradiction between comfort and heating speed.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the air volume is increased early to promote room temperature rise, then heating efficiency improves, but cold air is blown onto users causing discomfort

Engineering Contradiction:
Improveheating efficiencyVSAvoidcold air blow out
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by requiring the indoor heat exchanger to reach a predetermined temperature threshold before the indoor fan begins operating. This preliminary heating phase ensures the heat exchanger is sufficiently warm before air circulation starts, preventing cold air blowout while enabling subsequent high-efficiency heating operation.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If a single temperature threshold is used for air volume control, then control simplicity is maintained, but both cold air reduction and temperature rise promotion cannot be optimized

Engineering Contradiction:
Improvecontrol system simplicityVSAvoidcold air discomfort and slow heating
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent applies segmentation by dividing the temperature control range into two distinct segments: below the first temperature threshold and above the first temperature threshold. Each segment has its own control strategy (different air volume restrictions), allowing optimized control for both comfort and heating efficiency while maintaining relatively simple implementation through clear threshold-based decision logic.

Inventive Principle:
Principle #1Segmentation

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 approach effectively reduces user discomfort from cold air and enhances room temperature rise, improving user comfort and heating efficiency by selectively managing air volume and direction.

Implementation Method 1

an indoor heat exchanger configured to exchange heat between refrigerant and indoor air in a vapor compression refrigeration cycle

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3578897B1Air conditioner
Publication Date: 2021.04.14 DAIKIN INDUSTRIES LTD
  • EP3578897B1 patent drawingFigure 1
  • EP3578897B1 patent drawingFigure 2
  • EP3578897B1 patent drawingFigure 3

AI summary

To reduce uncomfortable feeling due to cold air and promote a rise in room temperature in an air conditioner that performs heating through a vapor compression refrigeration cycle. An indoor heat exchanger (16) exchanges heat between refrigerant and indoor air in the vapor compression refrigeration cycle. An indoor fan (31) is configured to change an air volume at a time of blowing out, into a room, conditioned air obtained through the heat exchange by the indoor heat exchanger. An air conditioner (1) performs, when starting heating, first cold air reduction control for restricting the air volume of the indoor fan (31) until a temperature of the indoor heat exchanger (16) reaches a first temperature, and second cold air reduction control for cancelling the air volume restriction at the indoor fan (31) when the temperature of the indoor heat exchanger (16) reaches a second temperature lower than the first temperature.