Air Conditioner Refrigerant Pooling Prevention Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In multi-type air conditioners, refrigerant accumulates excessively in indoor heat exchangers during thermostat OFF states or heating operation stops, leading to reduced air conditioning capacity and potential overheating, insufficient heating, and abnormal sounds.
Innovation Solution
A control method that includes stopping the fan and increasing the opening degree of the expansion valve in the indoor unit when the thermostat OFF state or heating operation is stopped, followed by shutting off refrigerant flow through the heat exchanger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fan continues to operate in thermostat OFF state during heating operation, then heat exchange continues and indoor air circulation is maintained, but refrigerant accumulates excessively in the indoor heat exchanger causing capacity loss and potential overheating
Solution Approach 1:
The control device performs preliminary action by stopping the fan before refrigerant accumulation becomes problematic. When the thermostat OFF state is detected during heating operation, the fan is stopped in advance to prevent excessive refrigerant condensation in the indoor heat exchanger, thereby maintaining system reliability and preventing capacity loss.
2Reliability
If the expansion valve opening is reduced to prevent refrigerant accumulation, then refrigerant flow to indoor heat exchanger is limited, but this causes insufficient heating and potential abnormal sounds
Solution Approach 1:
The control device stops the fan in advance when thermostat OFF state is detected, preventing refrigerant accumulation before it occurs. This preliminary action eliminates the need to restrict expansion valve opening, thereby maintaining proper refrigerant flow and heating performance without causing insufficient heating or abnormal sounds.
3Reliability
If refrigerant flow is shut off completely to prevent accumulation, then refrigerant supply to indoor heat exchanger is stopped, but this causes insufficient heating when heating operation is needed
Solution Approach 1:
The control device dynamically adjusts fan operation based on system state. The fan is stopped only during thermostat OFF state to prevent refrigerant accumulation, while resuming operation when heating is needed. This dynamic control prevents accumulation without compromising heating capacity, as the fan operates normally during active heating periods.
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
Reduces refrigerant accumulation in indoor heat exchangers, preventing capacity loss and overheating, while minimizing abnormal sounds.
Implementation Method 1
increasing an opening degree of an expansion valve provided in the indoor unit
Implementation Method 2
a gas refrigerant supplied to the indoor heat exchanger is condensed and liquefied
Implementation Method 3
heat exchange between the refrigerant flowing through the indoor heat exchanger of the indoor unit 20 and the indoor air
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
Provided is an air conditioner having a function for preventing pooling of refrigerant when an air-warming operation is thermally off or stopped. A multi-type air conditioner having an outdoor unit, a plurality of indoor units, and a control device, the outdoor unit and the plurality of indoor units being connected by refrigerant piping, wherein the control device has: a means for stopping a fan provided to an indoor unit that is executing an air-warming operation when the indoor unit is thermally off, where the indoor temperature has reached a set temperature so that heat exchange in the indoor heat exchanger is unnecessary, or when the indoor unit assumes an air-warming stop state in which the air-warming operation is stopped; a means for increasing the opening degree of an expansion valve provided to the indoor unit when the indoor unit assumes the air-warming stop state; and a means for blocking refrigerant from flowing into and out of the indoor heat exchanger provided to the indoor unit after the fan has been stopped and the opening degree of the expansion valve has been increased.