Vehicle Heat Pump Circuit Without Refrigerant Flow Reversal

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing vehicle air conditioning systems struggle to effectively use the same refrigerant for both cooling and warming without reversing the refrigerant circuit flow, leading to inefficiencies and requiring separate systems for cooling and heating, which increases complexity and component count.

Innovation Solution

The system connects the outer low-pressure circuits such that the condenser warms liquid for the vehicle space and the evaporator cools liquid, allowing for seamless operation without flow reversal, using a flow changeover switch to unite secondary circuits for heat pump operation without altering the main flow direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the refrigerant circuit flow is reversed to enable heating mode, then the system can provide warming function, but the condenser and evaporator function less effectively, reducing system efficiency

Engineering Contradiction:
Improveheating functionVSAvoidsystem efficiency
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The system divides the heating and cooling functions into separate circuits: a refrigerant circuit for cooling and a water-borne circuit for heating. This segmentation allows each circuit to operate independently with optimized components, avoiding the efficiency loss that would occur from reversing the refrigerant circuit flow.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The compressor system serves multiple functions through its dual-circuit design: it provides cooling via the refrigerant circuit and heating via the water-borne circuit. The compressor drives both circuits simultaneously or independently, enabling the system to function as both an air conditioner and a heat pump without reversing flows.

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

2Adaptability or versatility

If a separate water-borne heating system is used for warming the cab, then heating function is provided, but the system complexity and component count increase

Engineering Contradiction:
Improveheating functionVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the cooling and heating systems into a single integrated compressor system. The compressor drives both the refrigerant circuit (for cooling) and the water-borne circuit (for heating), eliminating the need for separate heating and cooling systems and reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The compressor system is designed to perform both cooling and heating functions through its dual-circuit architecture. By making the compressor universal—capable of driving both refrigerant and water circuits—the system achieves multi-functionality without requiring separate dedicated systems for each function.

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

3Adaptability or versatility

If the engine cooling water is used for heating the cab, then heating is provided, but the response time is delayed as the large mass of engine cooling water takes time to warm up

Engineering Contradiction:
Improveheating functionVSAvoidresponse time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The system extracts the heating function from the engine cooling system by creating a separate water-borne circuit that is driven directly by the compressor. This extracted circuit uses a smaller volume of water that can be heated quickly and delivered to the cab immediately, rather than relying on the large thermal mass of the engine cooling water.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The compressor can pre-heat the water in the water-borne circuit before it is needed for cab heating. Since the circuit contains only a few litres of water rather than the engine's 100 litres, the water can be heated in advance and ready for immediate delivery to the cab when heating is required.

Inventive Principle:
Principle #10Preliminary action

4Adaptability or versatility

If a secondary liquid-based cooling circuit is used for vehicles with tiltable cabs, then cooling can be provided to the driving space, but the hose length and connection requirements increase

Engineering Contradiction:
Improvecooling coverageVSAvoidhose and connection complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the secondary cooling circuit with the heating circuit by using the same water-borne circuit for both cooling (when the cab needs cooling) and heating (when the cab needs warming). This unified approach reduces the number of separate hoses and connections compared to having entirely separate cooling and heating systems.

Inventive Principle:
Principle #5Merging (Combining)

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 ensures that the condenser and evaporator function optimally as intended, reducing component count and complexity, enabling efficient cooling and warming using the same refrigerant without flow alternation, and allowing quick heat production when needed.

Implementation Method 1

the condenser (6) of the refrigerant circuit (2) is adapted to warm liquid which is supplied to an element (13) in the vehicle's driving space

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

the evaporator (7) of the refrigerant circuit (2) is adapted to cool liquid which is released from the element (13)

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 3

a compressor (5), a condenser (6), an evaporator (7) and a flow changeover switch (16) which are connected to one another by means of pipelines to form a hermetically sealed system

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP2349757B1Method and system for cooling and warming
Publication Date: 2014.12.03 SCANIA CV AB
  • EP2349757B1 patent drawingFigure 1
  • EP2349757B1 patent drawingFigure 2
  • EP2349757B1 patent drawingFigure 3

AI summary

The invention relates to a method for cooling and warming purposes comprising a refrigerant circuit (2) with at least a compressor (5), a liquid-cooled condenser (6), a liquid-heated evaporator (7) and two outer secondary liquid-based circuits (3,4), the first (3) of which comprises an element (13) situated in the space which is to be cooled or warmed. The invention is achieved by the two secondary circuits (3,4) being united, during heat pump operation, to form a common single circuit so that the condenser (6) heats liquid which is supplied to the element (13), with the result that the element (13) releases heat instead of cold, without the flows in the primary refrigerant circuit (2), in the element circuit (3) or in the radiator circuit (4) being alternated/reversed.