Outdoor Heat Exchanger Bypass Control for Stable Heat Recovery
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Solution Overview
Problem
Existing air-conditioning apparatuses face challenges in lowering the heat conductance of outdoor heat exchangers sufficiently, leading to frequent compressor start and stop issues and inefficient heat recovery, which affects indoor comfort and energy savings.
Innovation Solution
The air-conditioning apparatus incorporates a bypass pipe with a flow control valve that adjusts refrigerant flow, utilizing the hydraulic head of an outdoor heat exchanger to reduce heat conductance by creating a bypass for refrigerant flow, allowing it to flow upward and downward with the heat medium, thereby controlling the heat exchange efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If refrigerant flow through the outdoor heat exchanger is reduced to lower heat conductance, then heat exchange amount is lowered, but compressor reliability deteriorates due to frequent start and stop
Solution Approach 1:
The outdoor heat exchanger is divided into multiple heat exchange sections, allowing selective control of refrigerant flow through different sections. This segmentation enables precise adjustment of heat conductance while maintaining sufficient heat exchange capacity to prevent compressor cycling
Solution Approach 2:
The invention changes the flow distribution parameters within the heat exchanger by adjusting the opening degrees of expansion valves for each indoor unit. This parameter adjustment optimizes refrigerant flow distribution to achieve desired heat conductance while maintaining system reliability
2Adaptability or versatility
If heat conductance of outdoor heat exchanger is lowered to enable full heat recovery operation, then heat exchange amount is reduced, but system complexity increases
Solution Approach 1:
The outdoor heat exchanger is designed to perform multiple functions: it serves as both a cooling heat exchanger and a heating heat exchanger, and can operate in different modes (full heat recovery, partial heat recovery, cooling-only, heating-only). This multi-functionality is achieved through the variable expansion valves that control refrigerant flow distribution to different heat exchange sections
Solution Approach 2:
The system employs dynamically adjustable expansion valves that can change their opening degrees in real-time based on operational requirements. This dynamic control enables the heat exchanger to adapt its heat conductance and flow distribution according to different operational modes without requiring physically different configurations
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 lowers the heat conductance of the outdoor heat exchanger, improving indoor comfort and energy savings by stabilizing the refrigeration cycle and enhancing controllability during various operational modes.
Implementation Method 1
utilizing the hydraulic head of an outdoor heat exchanger to reduce heat conductance by creating a bypass for refrigerant flow
Implementation Method 2
an outdoor heat exchanger (35) through which each of refrigerant and a heat medium flows
Implementation Method 3
exchanging heat between the refrigerant and a heat medium that enters the outdoor heat exchanger
Data Source
AI summary
An air-conditioning apparatus includes a compressor for compressing and discharging refrigerant; an outdoor heat exchanger for exchanging heat between the refrigerant and a heat medium that enters the outdoor heat exchanger; an indoor heat exchanger for exchanging heat between the refrigerant and a surrounding medium of use; a bypass pipe for bypassing the refrigerant that is to enter the outdoor heat exchanger; and a bypass flow control valve arranged on the bypass pipe, for adjusting a flow of the refrigerant that is to enter the outdoor heat exchanger, in which the outdoor heat exchanger includes a first passage through which the refrigerant flows, and a second passage through which the heat medium flows, and in which the first passage allows the refrigerant to flow upward.