Regenerative air conditioner

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Solution Overview

Problem

Air conditioners face efficiency decline and comfort issues due to compressor operational inefficiencies at low air-conditioning loads, leading to repeated on/off operations and temperature variations.

Innovation Solution

A thermal storage air conditioner with an operation control section that switches between simple cooling/heating operations and thermal energy storage operations to maintain optimal compressor speed, reducing inefficiencies and eliminating the need for on/off cycles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the rotational speed of the compressor is reduced to match low air-conditioning load, then the air-conditioning capacity matches the load, but the compressor efficiency declines

Engineering Contradiction:

Improveair-conditioning capacity matchingVSAvoidcompressor efficiency

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The thermal storage medium is cooled in advance during high-load periods when the compressor operates at high efficiency, storing cold thermal energy. During low-load periods, this pre-stored cold energy is utilized to maintain compressor efficiency while meeting the reduced cooling demand.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The compressor operates continuously at optimal rotational speed without on/off cycling. The thermal storage system provides continuous cooling by releasing pre-stored cold energy, eliminating the need to reduce compressor speed and maintaining continuous useful action at peak efficiency points.

Inventive Principle:

Principle #20Continuity of useful action

2Productivity

If the compressor operates in on/off mode at low load, then the air-conditioning capacity is controlled, but the room temperature stability deteriorates

Engineering Contradiction:

Improveair-conditioning capacity controlVSAvoidroom temperature stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The thermal storage medium acts as an intermediary between the compressor and the room cooling demand. It absorbs excess cold energy when demand is high and releases it when demand is low, mediating temperature fluctuations and preventing direct on/off cycling effects on room temperature.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the operational parameters by introducing a thermal storage component that decouples the compressor operation from direct room temperature control. This allows the compressor to operate at stable parameters while the thermal storage buffer handles temperature regulation.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If the compressor rotational speed is repeatedly adjusted, then the air-conditioning load is matched, but the operational efficiency and comfort deteriorate

Engineering Contradiction:

Improveload matchingVSAvoidoperational efficiency and comfort

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

Cold thermal energy is stored in advance in the thermal storage medium during periods of high cooling demand. This preliminary action allows the system to meet low-load demands without adjusting compressor speed, thereby maintaining operational efficiency and comfort.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system employs periodic charging and discharging of the thermal storage medium. During high-load periods, the storage medium is charged with cold energy; during low-load periods, it discharges this energy, creating a periodic action that smooths out the need for frequent compressor speed adjustments.

Inventive Principle:

Principle #19Periodic action

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 enhances compressor efficiency, reduces power consumption, and maintains room comfort by adjusting operational modes based on load conditions, thereby minimizing temperature fluctuations.

Implementation Method 1

the refrigerant is condensed in the outdoor heat exchanger (23)

Methodology Applied

Scientific EffectCondensation: Condensation

Implementation Method 2

the refrigerant is condensed in the outdoor heat exchanger (23) and evaporates in the indoor heat exchanger (72)

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 3

a thermal storage section (60) which has a thermal storage medium and exchanges heat between the thermal storage medium and a refrigerant of the refrigerant circuit (11)

Methodology Applied

Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentUS10539335B2Regenerative air conditioner

Publication Date: 2020.01.21 DAIKIN INDUSTRIES LTD

AI summary

To avoid decline in the efficiency of a compressor at a low load, the thermal storage air conditioner has an operation controller which, if a rotational speed of the compressor is slowed down to a predetermined lower reference value in a simple cooling operation, switches operation of the thermal storage air conditioner from the simple cooling operation to a cooling and cold thermal energy storage operation to increase the rotational speed of the compressor. During the simple cooling operation refrigerant is condensed in the outdoor heat exchanger and evaporates in the indoor heat exchanger, and during a cooling and cold thermal energy storage operation the refrigerant is condensed in the outdoor heat exchanger, evaporates in the indoor heat exchanger, and the thermal storage medium in the thermal storage section is cooled by the refrigerant.