Outdoor Unit Compression Switching for Low-Temperature Heating
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Solution Overview
Problem
Existing air conditioner systems face inefficiencies in compression modes, particularly outside units, which are either inefficient in one-stage compression or suffer capacity loss in two-stage compression except at very low outdoor temperatures, leading to suboptimal operation in various conditions.
Innovation Solution
The system includes two outdoor units connected via two-stage compression lines, allowing switching between one-stage and two-stage compression modes without additional devices, utilizing valves to manage refrigerant flow and heat exchanger connections for efficient operation across different temperature conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If two-stage compression is used to achieve required pressure ratio at very low outdoor temperatures, then the pressure ratio requirement is met, but capacity and efficiency deteriorate seriously in other operating conditions
Solution Approach 1:
The system dynamically switches between one-stage and two-stage compression modes based on outdoor temperature conditions. When outdoor temperature is very low, the system activates two-stage compression to achieve required pressure ratio. When outdoor temperature is not very low, the system uses one-stage compression to maintain high capacity and efficiency. This dynamic adaptation resolves the contradiction between meeting pressure ratio requirements at low temperatures and maintaining productivity in other conditions.
2Temperature
If multiple outdoor systems are connected in series for two-stage compression, then pressure ratio is achieved at very low temperatures, but system complexity increases
Solution Approach 1:
Each outdoor unit is designed with multi-functionality to serve both as a standalone one-stage compression unit and as part of a two-stage compression system. The outdoor units include necessary components (compressors, heat exchangers, expansion valves, four-way valves) that enable them to function independently or in series. This universal design allows the system to achieve pressure ratio at very low temperatures when needed, while maintaining simpler configuration in normal conditions, thus resolving the contradiction between temperature adaptation and system complexity.
3Ease of operation
If outdoor units are connected in parallel for refrigerant circulation, then system operation is simplified, but pressure ratio cannot be achieved at very low outdoor temperatures
Solution Approach 1:
The system dynamically reconfigures the connection topology between outdoor units based on operating conditions. Under normal conditions, outdoor units are connected in parallel for simplified operation. When outdoor temperature drops to very low levels, the system switches to series connection to achieve the required pressure ratio. This dynamic reconfiguration capability allows the system to maintain ease of operation in normal conditions while achieving temperature adaptation when needed.
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 enables the air conditioner to operate efficiently in various modes, optimizing heating performance by adapting to outdoor temperatures through one-stage or two-stage compression, while minimizing space requirements and utilizing existing refrigerant pipes effectively.
Implementation Method 1
a compressor and an expansion valve, and a heat exchanger connected in this order via refrigerant tubes
Implementation Method 2
an outdoor heat exchanger for exchanging heat with outdoor air is disposed in the outdoor system
Implementation Method 3
a compressor and an expansion valve, and a heat exchanger connected in this order via refrigerant tubes
Data Source
Figure 1
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Figure 3
AI summary
The present invention relates to an outdoor system for an air conditioner. In an air conditioner which comprises at least one outdoor system, the at least one outdoor system comprises: a compressor; an outdoor heat exchanger; a pair of two-stage compression lines extending to the outside of the outdoor system; a pair of connection lines extending to the outside of the outdoor system and communicating with an indoor unit; and multiple valves for opening/closing the pair of two-stage compression lines and the pair of connection lines when the outdoor system is operated in a one-stage heating mode or two-stage heating mode.