Injection Heat Exchanger for Low-Temperature Heating Capacity
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Solution Overview
Problem
In air-conditioning apparatuses using refrigeration cycles, low outdoor temperatures can lead to insufficient refrigerant injection, resulting in excessive discharge temperature and reduced capacity, as the refrigerant may not be adequately cooled before being supplied to indoor units for heating.
Innovation Solution
An air-conditioning apparatus with an injection internal heat exchanger that exchanges heat between the refrigerant stream flowing through the injection pipe and the refrigerant stream passing through the heat-source-side heat exchanger, allowing for controlled refrigerant injection into the compressor's intermediate portion, thereby regulating the discharge temperature and maintaining capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If refrigerant is injected via injection pipe into intermediate portion of compression stroke to improve heating capacity, then heating capacity is improved, but discharge temperature rises excessively when outdoor air temperature is low
Solution Approach 1:
The injection internal heat exchanger serves as an intermediary device between the injection pipe and the heat-source-side heat exchanger. It allows heat exchange between the injected refrigerant stream and the refrigerant stream from the heat-source-side heat exchanger, thereby cooling the injected refrigerant before it enters the compressor and preventing excessive discharge temperature while maintaining improved heating capacity.
Solution Approach 2:
The invention changes the temperature parameter of the injected refrigerant by introducing it to the injection internal heat exchanger where it absorbs heat from the refrigerant stream returning from the heat-source-side heat exchanger. This temperature adjustment ensures the injected refrigerant is at an appropriate temperature to prevent excessive discharge temperature while still improving heating capacity.
2Power
If refrigerant is injected to increase density of discharged refrigerant, then heating capacity is improved, but sufficient differential pressure cannot be obtained when outdoor air temperature is low
Solution Approach 1:
The injection internal heat exchanger acts as an intermediary that facilitates heat exchange between the injected refrigerant and the refrigerant from the heat-source-side heat exchanger. This heat exchange process helps maintain appropriate pressure differential by controlling the temperature and state of the injected refrigerant, ensuring sufficient differential pressure is obtained while still achieving improved heating capacity through increased refrigerant density.
3Ease of operation
If injection pipe connects to portion where refrigerant is divided, then heated gas refrigerant can be supplied to indoor units, but total circulation amount must be increased to ensure satisfactory capacity
Solution Approach 1:
The injection internal heat exchanger serves as an intermediary that efficiently utilizes the heat from the refrigerant stream returning from the heat-source-side heat exchanger to cool the injected refrigerant. This heat recovery mechanism allows the system to maintain satisfactory heating capacity with optimized refrigerant circulation rather than requiring a substantial increase in total circulation amount.
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 effectively suppresses the rise in discharge temperature and ensures a satisfactory heating capacity even in low outdoor temperatures by optimizing refrigerant flow and heat exchange, ensuring efficient operation of the air-conditioning system.
Implementation Method 1
an injection internal heat exchanger that exchanges heat between a refrigerant stream that flows through the injection pipe and a refrigerant stream that flows into the heat-source-side heat exchanger after passing through the indoor unit
Implementation Method 2
a heat-source-side heat exchanger that exchanges heat between the refrigerant and outdoor air
Data Source
AI summary
An air-conditioning apparatus includes an injection pipe allowing a part of a refrigerant, as discharged from a compressing device, to flow into an intermediate portion of a compression stroke of the compressing device, and an injection internal heat exchanger that exchanges heat between a refrigerant stream that flows through the injection pipe and a refrigerant stream that flows into a heat-source-side heat exchanger after passing through an indoor unit.