Auxiliary Heat Exchanger Control for Low-Temperature Air Conditioner Heating
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Solution Overview
Problem
Air conditioners face issues with poor heating performance at low temperatures due to frost formation on outdoor heat exchangers and compressor damage from prolonged small-load operations, leading to inefficient energy use and potential compressor failure.
Innovation Solution
The air conditioner system incorporates a refrigeration system with a four-way valve, an auxiliary heat exchanger, and throttle components to divert refrigerant branches for enhanced heat exchange, preventing oil shortages and improving evaporation pressure and temperature during small-load operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the air conditioner operates in heating mode at low temperature, then the outdoor heat exchanger absorbs heat from the air, but frost formation reduces the heat absorption efficiency
Solution Approach 1:
The patent divides the refrigerant flow into multiple branches using a multi-position valve. One branch passes through the outdoor heat exchanger while another branch bypasses it, allowing selective control of refrigerant flow paths to optimize heat exchange while preventing frost accumulation.
Solution Approach 2:
The patent introduces an auxiliary heat exchanger as an intermediary component to facilitate heat exchange between different refrigerant branches. This auxiliary heat exchanger helps transfer heat from the condensed refrigerant to the evaporating refrigerant, improving overall system efficiency.
2Use of energy by moving object
If the compressor operates at small load for a long period, then energy consumption is reduced, but lubricating oil cannot return to the compressor in time causing compressor damage
Solution Approach 1:
The patent uses the auxiliary heat exchanger as a mediator to create a temperature difference that drives lubricating oil back to the compressor. The auxiliary heat exchanger cools the refrigerant in one branch, creating a density difference that promotes oil return to the compressor even during small-load operation.
Solution Approach 2:
The patent changes the temperature and pressure parameters of the refrigerant by routing it through different paths. By controlling the multi-position valve, the system creates favorable temperature and pressure conditions that ensure proper lubricating oil circulation and return to the compressor.
3Productivity
If the refrigerant flow is increased to improve heat exchange, then heating efficiency improves, but the discharge temperature may exceed the heat-resistant temperature of the compressor
Solution Approach 1:
The patent segments the refrigerant flow into multiple branches with different functions. One branch handles the main heating load while another branch is controlled to manage discharge temperature, ensuring that the compressor operates within safe temperature limits while maintaining heating efficiency.
Solution Approach 2:
The system uses feedback control through the multi-position valve to monitor and adjust refrigerant flow based on discharge temperature conditions. When discharge temperature approaches the heat-resistant limit, the valve adjusts the flow distribution to reduce compressor discharge temperature while maintaining acceptable heating performance.
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 air conditioner's low-temperature heating capability, prevents compressor damage, and improves overall heat exchange efficiency by effectively utilizing the heat of condensed refrigerant.
Implementation Method 1
the refrigerant of one branch enters the second passage of the auxiliary heat exchange after passing through the indoor heat exchanger and being throttled by the second throttle component, the refrigerant of another branch can directly enter the first passage of the auxiliary heat exchanger through the second four-way valve, and then the two branches of refrigerants exchange heat
Implementation Method 2
the first throttle component and the second throttle component can be controlled to open, and the first port and the fourth port of the four-way valve are controlled to be communicated. In this way, the refrigerant after passing through the first four-way valve is divided into two branches
Implementation Method 3
a first four-way valve, an outdoor heat exchanger, and an indoor heat exchanger; a second four-way valve, a first port of which is connected to a pipeline between the first four-way valve and the indoor heat exchanger
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present disclosure provides an air conditioner system and a control method for the same. The air conditioner system includes: a refrigeration system. A first port of a second four-way valve is connected to a pipeline between the first four-way valve and the indoor heat exchanger, and a second port of a second four-way valve is connected to a first position in a pipeline between the indoor heat exchanger and the outdoor heat exchanger. A first port of the first passage of an auxiliary heat exchanger is in communication with a fourth port of the second four-way valve, and a second port of the first passage is connected to a second position in a pipeline between the indoor heat exchanger and the outdoor heat exchanger. A first port of the second passage is connected to a third position in the pipeline between the indoor heat exchanger and the outdoor heat exchanger, and a second port of the second passage is connected to a pipeline between the outdoor heat exchanger and a return-air inlet of the compressor. A first throttle component is disposed in a pipeline of the first passage. A second throttle component is disposed on a pipeline between the first port of the second passage and the third position.