Heat Exchanger Switching Layout for Uniform Refrigerant Distribution
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Solution Overview
Problem
In air-conditioning apparatuses, the existing techniques for connecting heat exchangers in series or parallel for refrigerant flow lead to inefficiencies, such as reduced refrigeration cycle efficiency and frost formation, which impair power-saving performance and indoor comfort.
Innovation Solution
An air-conditioning apparatus with a distribution adjustment header that adjusts refrigerant distribution at specific points in the circuit, allowing heat source side heat exchangers to be connected in series during cooling operations and in parallel during heating operations, reducing pressure loss and ensuring uniform refrigerant distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If heat source side heat exchangers are connected in parallel for heating operation, then pressure loss in evaporators is reduced and evaporator performance is improved, but refrigerant distribution becomes non-uniform according to heat transfer area and air velocity distribution
Solution Approach 1:
A distributor is introduced as an intermediary component in the refrigerant flow path to mediate between the parallel-connected heat exchangers and the refrigerant supply. The distributor actively adjusts and equalizes refrigerant distribution to each heat exchanger based on their specific heat transfer areas and operating conditions, ensuring uniform refrigerant allocation while maintaining the benefits of parallel connection for reduced pressure loss.
Solution Approach 2:
The system applies local quality by providing customized refrigerant distribution to each heat exchanger based on its individual characteristics, particularly heat transfer area. Each heat exchanger receives the appropriate amount of refrigerant tailored to its specific requirements, rather than uniform distribution, optimizing performance while preventing frost formation.
2Speed
If heat source side heat exchangers are connected in series for cooling operation, then refrigerant flow speed increases and condenser performance is improved, but the system complexity increases due to flow path switching requirements
Solution Approach 1:
The system employs dynamic flow path switching that adapts the connection configuration (series or parallel) based on operating conditions such as heating or cooling mode. The switching mechanism dynamically reconfigures the refrigerant flow paths to optimize performance for each operating mode, maintaining high refrigerant flow speed during cooling while simplifying the overall system architecture through automated control.
3Productivity
If refrigerant flow is increased beyond evaporator processing capabilities during heating operation, then heating performance appears improved, but frost formation occurs on the evaporator
Solution Approach 1:
The distributor incorporates feedback mechanisms that monitor refrigerant flow conditions and heat exchanger performance in real-time. Based on this feedback, the distributor dynamically adjusts refrigerant distribution to maintain optimal flow rates that maximize heating performance while preventing conditions that lead to frost formation, ensuring stable and efficient operation.
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 the performance of both condensers and evaporators, prevents frost formation, and improves power-saving performance by maintaining refrigeration cycle efficiency and indoor comfort.
Implementation Method 1
the refrigerant transfers or removes heat to heat or cool indoor air, thereby performing heating or cooling of an air-conditioned space
Implementation Method 2
the refrigerant transfers or removes heat to heat or cool indoor air, thereby performing heating or cooling of an air-conditioned space
Implementation Method 3
refrigerant circulates, and the refrigerant transfers or removes heat
Data Source
AI summary
An air-conditioning apparatus includes a main circuit in which a compressor, a refrigerant flow switching device, a load side heat exchanger, a load side expansion device, and a plurality of heat source side heat exchangers are sequentially connected. When the plurality of heat source side heat exchangers are used as condensers, the first heat source side heat exchanger and the second heat source side heat exchanger are connected in series. When the plurality of heat source side heat exchangers are used as evaporators, the first heat source side heat exchanger and the second heat source side heat exchanger are connected in parallel. A distribution adjustment header on an inlet side of at least either the first heat source side heat exchanger or the second heat source side heat exchanger when the plurality of heat source side heat exchangers are used as evaporators.