Refrigeration cycle device

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Solution Overview

Problem

In heat pump type hot water supply devices, high feed-water temperatures can cause refrigerant at the condenser outlet to enter a gas-liquid two-phase or gas state, increasing refrigerant flow speed and pressure loss, which reduces efficiency by allowing the refrigerant to draw heat from water at a lower temperature, thereby decreasing heating efficiency.

Innovation Solution

A refrigeration cycle device with a divided condenser system, including a first condenser and a second condenser, where a second condenser bypass passage allows for increased refrigerant flow bypass when high heat medium temperatures are detected, preventing heat transfer between the refrigerant and water in the second condenser.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the feed-water temperature is high (50°C or higher), then the heating capacity of the condenser is improved, but the refrigerant pressure loss increases and heating efficiency decreases

Engineering Contradiction:
Improvefeed-water temperatureVSAvoidheating efficiency
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The condenser is divided into a first condenser and a second condenser connected in series. The first condenser handles refrigerant condensation at higher temperatures, while the second condenser handles lower temperature heat exchange. This segmentation allows optimization of heat exchange efficiency at different temperature levels, preventing the refrigerant from absorbing heat from the heat medium in the second condenser.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A bypass passage with a bypass valve is introduced as an intermediary element between the first and second condensers. This bypass allows the refrigerant to skip the second condenser when feed-water temperature is high, preventing the harmful heat absorption effect while still allowing the refrigerant to flow through the system. The bypass valve acts as a control mediator to regulate refrigerant flow based on operating conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If the feed-water temperature is high, then the condenser can handle higher temperature heat medium, but the refrigerant flow speed increases causing higher pressure loss

Engineering Contradiction:
Improveheat medium temperatureVSAvoidrefrigerant pressure loss
Core Design Contradiction:
TemperatureVSStress or pressure

Solution Approach 1:

The condenser is divided into a first condenser and a second condenser connected in series. The first condenser handles refrigerant condensation at higher temperatures, while the second condenser handles lower temperature heat exchange. This segmentation allows optimization of heat exchange efficiency at different temperature levels, preventing the refrigerant from absorbing heat from the heat medium in the second condenser.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A bypass passage with a bypass valve is introduced as an intermediary element between the first and second condensers. This bypass allows the refrigerant to skip the second condenser when feed-water temperature is high, preventing the harmful heat absorption effect while still allowing the refrigerant to flow through the system. The bypass valve acts as a control mediator to regulate refrigerant flow based on operating conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Temperature

If the refrigerant temperature is lower than the heat medium temperature in part of the condenser, then heat transfer occurs from heat medium to refrigerant, but this reduces condenser heating efficiency

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidcondenser heating efficiency
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The condenser is divided into a first condenser and a second condenser connected in series. The first condenser handles refrigerant condensation at higher temperatures, while the second condenser handles lower temperature heat exchange. This segmentation allows optimization of heat exchange efficiency at different temperature levels, preventing the refrigerant from absorbing heat from the heat medium in the second condenser.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A bypass passage with a bypass valve is introduced as an intermediary element between the first and second condensers. This bypass allows the refrigerant to skip the second condenser when feed-water temperature is high, preventing the harmful heat absorption effect while still allowing the refrigerant to flow through the system. The bypass valve acts as a control mediator to regulate refrigerant flow based on operating conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 inhibits heat transfer in the second condenser during high feed-water temperatures, maintaining efficiency by preventing refrigerant from drawing heat from water at lower temperatures, thus enhancing the overall heating performance of the device.

Implementation Method 1

a condenser (heating device) configured to heat the heat medium with the refrigerant

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

a condenser (heating device) configured to heat the heat medium with the refrigerant

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP3059520B1Refrigeration cycle device
Publication Date: 2020.09.16 MITSUBISHI ELECTRIC CORP
  • EP3059520B1 patent drawingFigure 1
  • EP3059520B1 patent drawingFigure 2~3
  • EP3059520B1 patent drawingFigure 4

AI summary

The present invention has an object to provide a refrigeration cycle device capable of inhibiting a heat medium from heating refrigerant in a condenser when a temperature of the heat medium before heating is high. The refrigeration cycle device of the present invention includes: a first condenser; a second condenser having a smaller sectional area of a refrigerant flow path than the first condenser, for further condensing the refrigerant having passed through the first condenser; a heat medium path for passing a heat medium through the second condenser and the first condenser in this order; a second condenser bypass passage for bypassing the refrigerant flow path or the heat medium flow path in the second condenser; a flow path controlling element capable of varying a bypass rate of the refrigerant or the heat medium bypassing the second condenser; and control means for controlling the flow path controlling element so as to increase the bypass rate when a temperature of the heat medium before heat exchange with the refrigerant is high.