Two-Stage Refrigerant Circuit With Intermediate Battery Cooling

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Solution Overview

Problem

Existing refrigerant circuits for thermal conditioning devices, such as those in motor vehicles, lack efficiency in heat transfer and energy management, particularly in intermediate stages, which affects the cooling of vehicle components like batteries and power electronics.

Innovation Solution

A refrigerant circuit design featuring a first and second heat exchanger, compressors, expansion valves, and a cylinder for phase separation, with a third heat exchanger and flow redirection to enhance intermediate stages by passing two-phase refrigerant through the third heat exchanger for moderate temperature cooling, and using a flow control member to manage refrigerant flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a conventional refrigerant circuit with single evaporator and condenser is used, then the device complexity is low, but the heat transfer efficiency and energy management performance deteriorate

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidcircuit complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The single evaporator is segmented into two separate evaporators (first evaporator and second evaporator), each serving different thermal conditioning functions. The first evaporator handles passenger compartment cooling while the second evaporator provides additional cooling capacity or serves different temperature zones, thereby improving overall heat transfer efficiency and energy management

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The refrigerant circuit is designed with multi-functionality to handle various thermal conditioning requirements simultaneously. The system can operate in different modes (cooling, heating, defrosting) and serve multiple functions (passenger compartment conditioning, battery cooling, power electronics cooling) using the same refrigerant loop, improving energy utilization efficiency

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

2Temperature

If a third heat exchanger is added to enhance intermediate stage cooling, then the cooling capability for batteries and power electronics is improved, but the device complexity increases

Engineering Contradiction:
Improvecooling temperature for batteriesVSAvoidheat exchanger quantity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The third heat exchanger is integrated into the existing refrigerant circuit by nesting it within the intermediate stage between the expansion devices and evaporators. The refrigerant flows through the third heat exchanger as part of the existing loop, allowing battery and power electronics cooling to be achieved without creating a completely separate cooling system

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The third heat exchanger acts as an intermediary component that transfers heat from the refrigerant to the batteries and power electronics. It mediates the thermal energy transfer between the refrigerant circuit and the electronic components, enabling efficient cooling of these intermediate stage components

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If refrigerant flow is redirected through multiple paths, then the energy management and heat transfer efficiency are improved, but the flow control complexity increases

Engineering Contradiction:
Improvethermal conditioning efficiencyVSAvoidflow redirection mechanism
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The refrigerant flow paths are made dynamic through the use of electronic expansion valves and flow control members that can adjust their opening degrees based on system conditions. The system can dynamically redirect refrigerant flow to different evaporators and heat exchangers to optimize thermal conditioning efficiency for different operating modes and thermal loads

Inventive Principle:
Principle #15Dynamics

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 design improves the efficiency of thermal conditioning by effectively transferring heat from outside air and vehicle components to the passenger compartment, enhancing cooling capabilities for elements like batteries and power electronics.

Implementation Method 1

the first heat exchanger may be capable of exchanging heat between the refrigerant fluid and the air intended to emerge into a passenger compartment of a vehicle

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

the second heat exchanger being capable of exchanging heat with air outside the vehicle

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

the third heat exchanger being able to exchange heat with an element of the vehicle, such as for example a battery or power electronics

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 4

a cylinder capable of separating the liquid phase and the gaseous phase of the refrigerant

Methodology Applied
Scientific EffectPhase separation: Density Gradient

Implementation Method 5

a first expansion valve, a second expansion valve

Methodology Applied
Scientific EffectThrottling: Pressure Drop

Implementation Method 6

a first compressor, a second compressor

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP2933584B1Coolant circuit
Publication Date: 2019.02.06 VALEO SYST THERMIQUES SAS
  • EP2933584B1 patent drawingFigure 1~2

AI summary

The invention relates to a two-stage refrigerant circuit, comprising a first heat exchanger (1) forming a condenser, a second heat exchanger (2) forming an evaporator, a first compressor (C1), a second compressor (C2), a first expansion valve (D1), a second expansion valve (D2), a cylinder (B) suitable for separating the liquid and gaseous phases of the refrigerant, characterized in that it comprises a third heat exchanger (3) forming an evaporator.