Heat Pump Refrigerant Charge Isolation for Multi-Mode Operation

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Solution Overview

Problem

Heat pumps that both heat and cool spaces and heat water face inefficiencies due to inappropriate refrigerant charge levels during different modes of operation, requiring complex and expensive management systems or limiting their operational modes.

Innovation Solution

The system delivers hot refrigerant gas to unnecessary heat exchangers to drive out liquid refrigerant and isolates them, allowing the heat pump to operate while adjusting the refrigerant charge using digital controllers and valves, thereby managing refrigerant flow and optimizing efficiency across various modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complex refrigerant charge management hardware and systems are used to correct inappropriate refrigerant charge levels, then refrigerant charge management reliability is improved, but device complexity and cost increase

Engineering Contradiction:

Improverefrigerant charge management reliabilityVSAvoidrefrigerant charge management system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The heat pump system automatically manages its own refrigerant charge by using the compressor to deliver hot refrigerant gas to heat exchangers and by isolating heat exchangers through control valves, eliminating the need for external complex charge management hardware

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system changes the physical state and flow parameters of refrigerant by delivering hot refrigerant gas to heat exchangers and using control valves to isolate them, thereby dynamically adjusting refrigerant charge distribution without additional hardware

Inventive Principle:

Principle #35Parameter changes

2Reliability

If certain modes of operation are avoided to prevent inappropriate refrigerant charge levels, then refrigerant charge appropriateness is improved, but adaptability and operational versatility deteriorate

Engineering Contradiction:

Improverefrigerant charge appropriatenessVSAvoidoperational mode versatility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system dynamically adapts to different operational modes by selectively isolating heat exchangers based on real-time operating conditions, allowing the heat pump to operate efficiently in all modes including water heating with space cooling without suffering from inappropriate refrigerant charge

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control system changes operational parameters by isolating specific heat exchangers through control valves depending on the operational mode, enabling appropriate refrigerant charge management across diverse operating conditions

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If the heat pump operates in modes with accumulated liquid refrigerant in unused heat exchangers, then operational versatility is improved, but refrigerant charge efficiency deteriorates

Engineering Contradiction:

Improveoperational mode availabilityVSAvoidheat pump efficiency

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The system takes preliminary action by delivering hot refrigerant gas to heat exchangers before operation to drive out accumulated liquid refrigerant, preventing charge inefficiency before it occurs

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system rapidly addresses refrigerant charge issues by using the compressor to deliver hot refrigerant gas that quickly drives out liquid refrigerant from heat exchangers, eliminating the problem before it impacts efficiency

Inventive Principle:

Principle #21Skipping (Rushing through)

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 enhances the heat pump's efficiency, reduces complexity and cost, and allows for more operational modes, ensuring reliability and longevity while withstanding extreme conditions.

Implementation Method 1

a compressor to deliver hot refrigerant gas to a heat exchanger of the heat pump not needed at that time for transferring heat and drive liquid refrigerant out

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

deliver hot refrigerant gas to a heat exchanger... drive liquid refrigerant out

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS8756943B2Refrigerant charge management in a heat pump water heater

Publication Date: 2014.06.24 NORDYNE INC

AI summary

Heat pumps that heat or cool a space and that also heat water, refrigerant management systems for such heat pumps, methods of managing refrigerant charge, and methods for heating and cooling a space and heating water. Various embodiments deliver refrigerant gas to a heat exchanger that is not needed for transferring heat, drive liquid refrigerant out of that heat exchanger, isolate that heat exchanger against additional refrigerant flowing into it, and operate the heat pump while the heat exchanger is isolated. The heat exchanger can be isolated by closing an electronic expansion valve, actuating a refrigerant management valve, or both. Refrigerant charge can be controlled or adjusted by controlling how much liquid refrigerant is driven from the heat exchanger, by letting refrigerant back into the heat exchanger, or both. Heat pumps can be operated in different modes of operation, and segments of refrigerant conduit can be interconnected with various components.