Ejector refrigeration cycle device and low outside temperature operation thereof

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Solution Overview

Problem

Ejector refrigeration cycle devices face reduced suction capacity and cooling capacity at low outside-air temperatures due to decreased flow velocity and enthalpy of subcooled liquid-phase refrigerants, leading to inadequate refrigerant flow into the evaporator.

Innovation Solution

Incorporating an outside air temperature detector and an inflow-pressure increasing or vapor-quality increasing portion to adjust the pressure and vapor quality of the refrigerant flowing into the nozzle portion, ensuring adequate suction capacity and cooling performance across varying operating conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If subcooled liquid-phase refrigerant is used in the nozzle portion, then energy conversion efficiency is improved, but suction capacity decreases at low outside-air temperatures

Engineering Contradiction:

Improveenergy conversion efficiencyVSAvoidsuction capacity

Core Design Contradiction:

Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent changes the physical parameters of the refrigerant by increasing its enthalpy through vapor quality adjustment. By mixing high-pressure refrigerant from the compressor discharge with the subcooled liquid refrigerant, the system raises the enthalpy of the refrigerant entering the nozzle, ensuring adequate suction capacity at low outside-air temperatures while maintaining energy conversion efficiency.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces an intermediary substance (high-pressure refrigerant from compressor discharge) to modify the properties of the subcooled liquid refrigerant. This intermediary refrigerant acts as a heat transfer medium that increases the enthalpy of the mixed refrigerant before it enters the nozzle portion, resolving the contradiction between energy efficiency and suction capacity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If flow rate of injection refrigerant is decreased, then power consumption is reduced, but suction capacity is reduced

Engineering Contradiction:

Improvepower consumptionVSAvoidsuction capacity

Core Design Contradiction:

Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent changes the enthalpy parameter of the injection refrigerant by mixing it with high-pressure refrigerant from the compressor discharge. This parameter change allows the system to maintain suction capacity even when the flow rate is reduced, as the higher enthalpy refrigerant provides sufficient momentum for effective suction operation.

Inventive Principle:

Principle #35Parameter changes

3Temperature

If subcooled liquid-phase refrigerant with low enthalpy is used, then cooling effect is enhanced, but recovery energy decreases

Engineering Contradiction:

Improvecooling effectVSAvoidrecovery energy

Core Design Contradiction:

TemperatureVSLoss of energy

Solution Approach 1:

The patent optimizes the enthalpy parameter of the refrigerant entering the nozzle by mixing subcooled liquid refrigerant with high-pressure refrigerant from compressor discharge. This creates a balanced refrigerant state that provides sufficient cooling effect while maintaining adequate enthalpy for effective energy recovery in the diffuser portion.

Inventive Principle:

Principle #35Parameter changes

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

The solution maintains the ejector's suction capacity and evaporator cooling performance regardless of operating conditions, even at low outside-air temperatures, by preventing a decrease in flow velocity and increasing the enthalpy of the refrigerant.

Implementation Method 1

a nozzle portion that decompresses the refrigerant flowing out of the radiator

Methodology Applied

Scientific EffectIsentropic decompression: De Laval Nozzle

Implementation Method 2

a refrigerant suction port that draws a refrigerant by a suction effect of the injection refrigerant injected from the nozzle portion

Methodology Applied

Scientific EffectSuction effect: Suction

Implementation Method 3

a diffuser (pressurizing portion) of the ejector, thereby pressurizing the refrigerant

Methodology Applied

Scientific EffectKinetic energy recovery: Diffusion

Data Source

PatentUS10442274B2Ejector refrigeration cycle device and low outside temperature operation thereof

Publication Date: 2019.10.15 DENSO CORP

AI summary

An ejector refrigeration cycle device includes: a radiator that dissipates heat from a refrigerant discharged from a compressor; an ejector module that decompresses the refrigerant cooled by the radiator; and an evaporator that evaporates a liquid-phase refrigerant separated in a gas-liquid separation space of the ejector module. A grille shutter is disposed as an inflow-pressure increasing portion between the radiator and a cooling fan blowing the outside air toward the radiator. The grille shutter is operated to decrease the volume of the outside air to be blown toward the radiator when an outside air temperature is equal to or lower than a reference outside air temperature, thereby increasing the pressure of the inflow refrigerant to flow into a nozzle passage of the ejector module.