External Expansion Valve Layout for Multi-Indoor Air Conditioners
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Solution Overview
Problem
Conventional multi-type air conditioners face challenges in coexisting indoor units with and without decompression devices, leading to refrigerant imbalances when all units are operated simultaneously, resulting in insufficient refrigerant circulation and potential compressor failure due to excessive refrigerant when additional units are connected beyond the outdoor unit's capacity.
Innovation Solution
The air conditioner employs an external decompression device with an expansion valve and electromagnetic valve connected to refrigerant pipes, allowing for flexible connection of multiple indoor units to a single outdoor unit, with a control system to manage refrigerant distribution and prevent refrigerant shortages by collecting excess refrigerant from non-operational units during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple indoor units are connected to a single outdoor unit, then the flexibility and coverage of the air conditioning system is improved, but refrigerant imbalance occurs causing insufficient refrigerant circulation and potential compressor failure
Solution Approach 1:
An external decompression device is introduced as an intermediary component between the outdoor unit and indoor units. This device includes a decompression valve for adjusting refrigerant flow and an electromagnetic valve for controlling refrigerant supply to individual indoor units, thereby mediating the refrigerant distribution to prevent imbalance while allowing multiple units to operate simultaneously
Solution Approach 2:
The system implements dynamic control of refrigerant flow through the external decompression device. The decompression valve can be adjusted to change the degree of decompression, and the electromagnetic valve can be dynamically opened or closed based on operational requirements, allowing the refrigerant distribution to adapt to different operating conditions and prevent both refrigerant shortage and excess
2Adaptability or versatility
If the total capacity of indoor units exceeds the outdoor unit capacity, then more indoor units can be connected beyond design limits, but refrigerant becomes excessive causing liquid-back operation and compressor failure
Solution Approach 1:
The external decompression device is installed in advance in the refrigerant pipe before connecting multiple indoor units. The decompression valve is pre-configured to provide appropriate decompression, and the electromagnetic valve is positioned to control refrigerant flow to each indoor unit beforehand, preventing excessive refrigerant from reaching the indoor units and causing liquid-back operation
Solution Approach 2:
The system changes the refrigerant flow parameters by introducing decompression through the external decompression device. The decompression valve adjusts the pressure and flow rate of refrigerant, while the electromagnetic valve controls the timing and amount of refrigerant supplied to each indoor unit, thereby changing the refrigerant distribution parameters to prevent both shortage and excess conditions
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 ensures stable refrigerant circulation, preventing refrigerant shortages and compressor failures, enabling operation of multiple indoor units beyond the outdoor unit's capacity without refrigerant imbalances, enhancing air conditioning performance and reliability.
Implementation Method 1
an expansion valve (6) externally connected to the refrigerant pipe (D2)
Implementation Method 2
an electromagnetic valve (7) externally connected to the refrigerant pipe (D1)
Implementation Method 3
evaporator returns to the compressor
Implementation Method 4
heat exchange capacity of the indoor units
Implementation Method 5
compressor (10)
Implementation Method 6
indoor heat exchanger (4)
Data Source
Figure 1
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AI summary
There is disclosed an air conditioner having an outdoor unit (A) and plural indoor units (a,b) connected by refrigerant pipes. The plural indoor units (a,b) include a first unit having an expansion valve (5) and a heat exchanger (4) incorporated therein, and a second indoor unit having a heat exchanger (4) incorporated therein. A decompression device including an expansion valve (6) and an on-off valve (7) is connected at the middle of the outward and inward refrigerant pipes connecting the second indoor unit (b) with the outdoor unit (A). This makes it possible to connect different types of indoor units, namely, the first indoor units (a) having the decompression device (5) incorporated therein and the second indoor units having no decompression device incorporated therein.