Dual Expansion Valve Layout for Heat Pump Pressure Loss Control

Solution Overview

Problem

In heat pump type refrigeration cycle apparatuses, controlling the flow rate of refrigerant is challenging due to pressure loss when the expansion valve is located at either the outdoor or indoor heat exchanger, making it difficult to adapt to different operational modes.

Innovation Solution

The use of a dual expansion valve system with a piston-shaped valve seat and a driving member to control the flow rate by differential pressure, allowing for efficient flow control in both cooling and heating modes by reversing the refrigerant flow direction, reducing pressure loss and improving performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the expansion valve is provided at the outdoor heat exchanger side, then the refrigerant can be expanded before flowing into the indoor heat exchanger, but the expanded refrigerant is subject to pressure loss due to the long pipe line

Engineering Contradiction:

Improveflow rate controlVSAvoidpressure loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The expansion valve is divided into two independent valves: one located at the outdoor heat exchanger and another at the indoor heat exchanger. This segmentation allows each valve to independently control refrigerant flow at its respective location, eliminating the pressure loss issue that would occur with a single valve positioned at the outdoor unit controlling flow through a long pipe line.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the expansion valve is provided at the indoor heat exchanger side, then the refrigerant can be expanded at the indoor unit, but the same pressure loss problem occurs due to long pipe line

Engineering Contradiction:

Improveflow rate controlVSAvoidpressure loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The expansion valve is divided into two independent valves: one located at the outdoor heat exchanger and another at the indoor heat exchanger. This segmentation allows each valve to independently control refrigerant flow at its respective location, eliminating the pressure loss issue that would occur with a single valve positioned at the outdoor unit controlling flow through a long pipe line.

Inventive Principle:

Principle #1Segmentation

3Device complexity

If a single expansion valve is used in heat pump type refrigeration cycle apparatus, then the device complexity is reduced, but it is difficult to control the flow rate in both cooling and heating modes due to refrigerant flow direction changes

Engineering Contradiction:

Improvevalve systemVSAvoidflow rate control in different modes

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The expansion valve is divided into two independent valves: one located at the outdoor heat exchanger and another at the indoor heat exchanger. This segmentation allows each valve to independently control refrigerant flow at its respective location, eliminating the pressure loss issue that would occur with a single valve positioned at the outdoor unit controlling flow through a long pipe line.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each expansion valve is designed with bidirectional flow capability, allowing the outdoor expansion valve to control refrigerant flow in both cooling mode (outdoor to indoor) and heating mode (indoor to outdoor). This multi-functionality enables a single valve design to serve both operational modes effectively.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution enables precise control of the refrigerant flow rate in both cooling and heating modes, reducing pressure loss and enhancing the operational efficiency of the heat pump type refrigeration cycle apparatus.

Implementation Method 1

a flow rate of the refrigerant flowing from the sub valve chamber through a path between the valve plug and the valve port is controlled by closing the second port with the valve seat seated around the second port due to differential pressure between the first and second ports

Methodology Applied

Scientific EffectDifferential pressure: Pressure Gradient

Implementation Method 2

the refrigerant is discharged to the first port via the second port and the main valve chamber, said second port is opened by moving the valve plug in the axial direction with the driving member and by separating the valve seat from the second port due to the differential pressure between the second and first ports

Methodology Applied

Scientific EffectDifferential pressure: Pressure Gradient

Data Source

PatentUS8157183B2Expansion valve, heat pump type refrigeration cycle apparatus, and air handling unit

Publication Date: 2012.04.17 SAGINOMIYA SEISAKUSHO INC

AI summary

A first expansion valve is provided in an outdoor unit, and a second expansion valve is provided in an indoor unit. A pipe line connects a first joint pipe of the first expansion valve and a second joint pipe of the second expansion valve. When a refrigerant flows in from the second joint pipe and flows out from the first joint pipe, the first and second expansion valves are in a full open state due to pressure of the refrigerant. When the refrigerant flows in from the first joint pipe and flows out from the second joint pipe, the first and second expansion valves are in semi-closed state (flow rate controlling state). In a cooling mode, the second expansion valve expands the refrigerant just before an indoor heat exchanger, and in a heating mode, the first expansion valve expands the refrigerant just before an outdoor heat exchanger. In both heating and cooling mode, a large amount of refrigerant flows through the pipe line to reduce pressure loss.