Intermediate Heat Exchanger Flow Switching for Counterflow Cooling
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Solution Overview
Problem
The existing air-conditioning apparatus experiences suboptimal heat exchange efficiency in intermediate heat exchangers due to the fixed direction of the use-side refrigerant flow, which limits its performance across various operation modes.
Innovation Solution
The air-conditioning apparatus incorporates a primary-side refrigerant circuit with flow switching mechanisms and a secondary-side refrigerant circuit, allowing for counterflow configurations in intermediate heat exchangers, enabling flexible operation modes by switching refrigerant flow paths and directions to optimize heat exchange efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the use-side refrigerant flows in a fixed direction through intermediate heat exchangers, then the system structure is simple, but the heat exchange efficiency is suboptimal in parallel flow configurations
Solution Approach 1:
The patent implements dynamic flow direction control by equipping each intermediate heat exchanger with flow switching means that can change the flow direction of use-side refrigerant based on operation mode. This transforms the static parallel flow configuration into a dynamic system that can switch between parallel and counter flow configurations, thereby resolving the contradiction between structural simplicity and heat exchange efficiency.
Solution Approach 2:
The patent changes the flow direction parameter of the use-side refrigerant through flow switching means in response to different operation modes. By adjusting this parameter, the system achieves optimal heat exchange efficiency in both cooling and heating operations, transforming the fixed-direction limitation into a variable-parameter system that adapts to different operational requirements.
2Adaptability or versatility
If the primary-side refrigerant flow direction changes depending on operation mode, then the system is adaptable to different modes, but the heat exchange efficiency varies when use-side refrigerant remains in fixed direction
Solution Approach 1:
The patent makes the use-side refrigerant flow direction dynamic by introducing flow switching means controlled by mode switching means. This allows the system to maintain adaptability to different operation modes while simultaneously optimizing heat exchange efficiency by configuring counter flow in heating mode and parallel flow in cooling mode, resolving the contradiction between adaptability and efficiency.
Solution Approach 2:
The intermediate heat exchangers are designed with multi-functionality, serving both cooling and heating operations with optimized flow configurations for each mode. The flow switching means enables a single heat exchanger structure to perform optimally in both cooling and heating modes, achieving universality without sacrificing efficiency in either mode.
3Productivity
If intermediate heat exchangers operate in parallel flow configuration, then the system structure is simple, but optimum operation cannot be achieved in all operation modes
Solution Approach 1:
The patent transforms the static parallel flow configuration into a dynamic system where flow direction can be switched based on operation mode. The flow switching means, controlled by mode switching means, enables the system to achieve optimum performance in both cooling and heating modes by configuring counter flow in heating mode while maintaining parallel flow in cooling mode, justifying the added control complexity through significant performance improvement.
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 thermal efficiency by ensuring counterflow in intermediate heat exchangers, reducing the input to the pump and maintaining high heat exchange efficiency across cooling and heating operations, thereby optimizing the air-conditioning apparatus's performance in all modes.
Implementation Method 1
Each of the intermediate heat exchangers exchanges heat between the primary-side refrigerant and the secondary-side refrigerant
Implementation Method 2
The second flow switching means and the third flow switching means each switch a refrigerant flow path so that the primary-side refrigerant and the secondary-side refrigerant are in counterflow in at least one of the intermediate heat exchangers
Data Source
AI summary
An air-conditioning apparatus in which a primary-side refrigerant in a two-phase gas-liquid state that has flowed into each of intermediate heat exchangers absorbs heat from a secondary-side refrigerant flowing in counterflow to the primary-side refrigerant, and evaporates and turns into a low-temperature, low-pressure gas state. The air-conditioning apparatus ensures high heat exchange efficiency even when a direction of a heat source-side refrigerant (secondary-side refrigerant) flowing through an intermediate heat exchanger changes, and enables an appropriate operation in any operation mode.