HVAC unit with expansion device

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Solution Overview

Problem

Existing refrigeration systems face challenges in efficiently managing refrigerant flow and isolating refrigerant in case of leaks, particularly in multi-zone systems where maintaining optimal refrigerant distribution across indoor units is complex.

Innovation Solution

The proposed refrigeration system includes an outdoor unit with a compressor, heat exchanger, and expansion device, along with an indoor unit featuring a second heat exchanger and fan. The system employs isolation valves and expansion devices to manage refrigerant flow and isolate refrigerant in case of leaks, utilizing A2L refrigerant for efficient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If refrigerant lines extend from the outdoor unit to indoor units, then refrigerant distribution is enabled, but refrigerant loss increases in case of leaks

Engineering Contradiction:

Improverefrigerant chargeVSAvoidrefrigerant loss

Core Design Contradiction:

Quantity of substanceVSLoss of substance

Solution Approach 1:

The refrigeration system is divided into separate segments: the outdoor unit containing the compressor and first heat exchanger, and indoor units containing second heat exchangers. Isolation valves segment the refrigerant lines, allowing the system to isolate leaks to specific zones and prevent total system loss.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Isolation valves act as intermediaries between the outdoor unit and indoor units, controlling refrigerant flow and enabling rapid isolation of leaks. The expansion devices also serve as flow control intermediaries that can restrict refrigerant movement to minimize loss.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If isolation valves are installed to isolate leaks, then refrigerant capture is improved, but device complexity increases

Engineering Contradiction:

Improverefrigerant captureVSAvoidvalve configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The isolation valves serve multiple functions: they isolate refrigerant leaks, control refrigerant flow to specific zones, and enable maintenance of individual indoor units without shutting down the entire system. This multi-functionality justifies the added complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

Isolation valves are pre-installed in the refrigerant lines between the outdoor unit and indoor units, ready to quickly isolate leaks before they can spread throughout the system. This preliminary positioning enables rapid response to leaks.

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If expansion devices are placed in the outdoor unit, then refrigerant flow control is improved, but installation complexity increases

Engineering Contradiction:

Improverefrigerant flow controlVSAvoidoutdoor unit configuration

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The expansion devices are merged with the outdoor unit housing, consolidating multiple components (compressor, first heat exchanger, expansion devices, and isolation valves) into a single centralized unit. This simplifies installation and maintenance compared to distributed placement.

Inventive Principle:

Principle #5Merging (Combining)

4Loss of substance

If liquid refrigerant lines are contained within the outdoor housing, then refrigerant loss is reduced, but installation flexibility decreases

Engineering Contradiction:

Improverefrigerant lossVSAvoidinstallation flexibility

Core Design Contradiction:

Loss of substanceVSEase of manufacture

Solution Approach 1:

The refrigerant distribution system is segmented into a centralized outdoor unit containing all liquid refrigerant lines and expansion devices, with only necessary connection lines extending to indoor units. This segmentation minimizes exposed refrigerant lines while maintaining installation flexibility.

Inventive Principle:

Principle #1Segmentation

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 enhances refrigerant capture in case of leaks, reduces overall refrigerant charge, and allows for efficient temperature control across multiple zones, improving system reliability and energy efficiency.

Implementation Method 1

A heat exchanger is located within the housing and is in fluid communication with the compressor

Methodology Applied

Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 2

the heat exchanger is a condenser

Methodology Applied

Scientific EffectCondensation: Condensation

Implementation Method 3

At least one expansion device is located within the housing and is in fluid communication with the heat exchanger

Methodology Applied

Scientific EffectPressure reduction through expansion: Joule-Thomson Effect

Data Source

PatentUS12320561B2HVAC unit with expansion device

Publication Date: 2025.06.03 CARRIER CORP

AI summary

An outdoor HVAC unit includes a housing. A compressor is located within the housing. A heat exchanger is located within the housing and is in fluid communication with the compressor. At least one expansion device is located within the housing and is in fluid communication with the heat exchanger.