Heat pump apparatus and air conditioner or water heater having the heat pump apparatus mounted thereon

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Solution Overview

Problem

Existing heat pumps struggle to accurately detect frost formation on evaporators due to changes in indoor environments and compressor frequencies, leading to erroneous decisions about frost formation.

Innovation Solution

A heat pump system that uses evaporator sucked air temperature and evaporation pressure, along with compressor frequency, to calculate a characteristic value that detects frost formation by measuring the drop in heat exchange performance, thereby avoiding misdetctions caused by indoor changes and compressor frequency variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If evaporation temperature is used to detect frost formation, then detection simplicity is maintained, but detection accuracy deteriorates due to indoor environment changes and compressor frequency variations

Engineering Contradiction:
Improvedetection simplicityVSAvoidfrost formation detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent changes the detection parameter from evaporation temperature alone to a composite parameter combining evaporation pressure and compressor frequency. This allows the system to account for variations caused by indoor environment changes and compressor frequency adjustments, thereby improving detection accuracy while maintaining reasonable system complexity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system continuously monitors evaporation pressure and compressor frequency, and uses this feedback to dynamically adjust the frost formation determination. By comparing real-time pressure and frequency data against predetermined relationships, the system can accurately distinguish between temperature changes caused by operational variations and those caused by actual frost formation.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If evaporation pressure and compressor frequency are used to calculate characteristic value, then frost formation detection accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvefrost formation detection accuracyVSAvoiddetection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent leverages existing sensors and control systems that are already part of the heat pump apparatus. The microprocessor unit, which already controls compressor operation and monitors system parameters, is extended to perform additional calculations for frost detection. This multi-functional approach avoids adding dedicated detection hardware, thereby limiting complexity increase.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses its own operational parameters (compressor frequency and evaporation pressure) to detect frost formation, rather than requiring external or additional specialized sensors. The heat pump apparatus essentially detects its own state using data already being collected for control purposes, eliminating the need for separate detection infrastructure.

Inventive Principle:
Principle #25Self-service

3Speed

If defrosting operation is started based on temperature threshold, then response speed is maintained, but false defrosting operations occur due to erroneous frost detection

Engineering Contradiction:
Improvedefrosting response speedVSAvoiddefrosting operation reliability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The system continuously monitors evaporation pressure and compressor frequency, using this feedback to dynamically determine frost formation status. By comparing real-time data against predetermined relationships between pressure and frequency, the system can accurately distinguish between temperature changes caused by operational variations and those caused by actual frost formation, preventing false defrosting operations while maintaining timely response to genuine frost conditions.

Inventive Principle:
Principle #23Feedback

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 allows for accurate detection of frost formation on evaporators without being affected by indoor environment changes or compressor frequency fluctuations, ensuring timely and appropriate defrosting operations.

Implementation Method 1

an evaporator (6) that absorbs heat from air passing through the same

Methodology Applied
Scientific EffectHeat transfer: Convection

Data Source

PatentEP2157380B1Heat pump apparatus and air conditioner or water heater having the heat pump apparatus mounted thereon
Publication Date: 2019.10.02 MITSUBISHI ELECTRIC CORP
  • EP2157380B1 patent drawingFigure 1~2
  • EP2157380B1 patent drawingFigure 3~4
  • EP2157380B1 patent drawingFigure 5~6

AI summary

A heat pump that can accurately detect a frost formation state on an evaporator without being affected by changes in an indoor environment and changes in a compressor frequency, and an air conditioner or water heater on which the heat pump is mounted are provided. In the heat pump having a refrigerant circuit in which a compressor 3, an indoor heat exchanger 8 (condenser), an expansion valve 5, and an outdoor heat exchanger 6 (evaporator) are sequentially connected, evaporator refrigerant saturation temperature detecting means 10 for detecting an evaporation temperature Te of the outdoor heat exchanger 6, evaporator sucked air temperature detecting means 11 for detecting an evaporator sucked air temperature Ta of the outdoor heat exchanger 6, compressor frequency detecting means 12 for detecting a compressor frequency f of the compressor 3, and frost formation state detecting means 103 for detecting a frost formation state on the outdoor heat exchanger 6 are provided, and the frost formation state detecting means 103 detects a drop in heat exchange performance caused by a frost formation on the outdoor heat exchanger 6 on the basis of a characteristic amount T1, which is a calculation value obtained by dividing a difference between the evaporator sucked air temperature Ta and the evaporation temperature Te by a compressor frequency f.