Air Conditioner Heat-Medium Buffer to Delay Indoor Unit Stoppage
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Solution Overview
Problem
In multi-unit air-conditioning systems, if an abnormality occurs in one unit, it often leads to immediate stoppage of other units, causing secondary abnormalities and disrupting cooling or heating operations.
Innovation Solution
The system employs a heat medium separate from the refrigerant, which acts as a buffer, allowing the air-conditioning apparatus to continue operation even if an abnormality occurs in the heat source or relay unit by maintaining temperature within a predetermined range, thus delaying the stoppage of indoor units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the refrigerant supplied from the heat-source device flows directly into the indoor units, then the cooling or heating operation is efficient, but if an abnormality occurs in the heat-source device or relay unit, the indoor units must be stopped immediately causing secondary abnormalities
Solution Approach 1:
A heat medium (water or anti-freezing fluid) is introduced as an intermediary between the refrigerant and the indoor units. The refrigerant exchanges heat with the heat medium in a heat exchanger, and the heat medium then flows to the indoor units. This intermediary allows the indoor units to continue operating temporarily even if the heat-source device stops, as the heat medium retains heat capacity that can be utilized during the transition period.
2Reliability
If a heat medium different from the refrigerant is introduced to flow into the indoor units, then the stoppage of indoor units can be delayed when an abnormality occurs, but the system complexity increases due to additional heat exchangers and heat medium circulation paths
Solution Approach 1:
The heat medium circulation system serves multiple functions: it acts as a heat transfer medium from the refrigerant to the indoor units, functions as a buffer to delay stoppage during abnormalities, and enables the indoor units to operate independently for a period after the heat-source device stops. This multi-functionality justifies the additional complexity by providing significant operational reliability benefits.
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 system to maintain operation and delay the stoppage of indoor units by using the heat medium as a buffer, ensuring continuous cooling or heating within predetermined temperature ranges, even if an abnormality occurs in the heat source or relay unit.
Implementation Method 1
a heat medium different from the refrigerant supplied from the heat-source device is configured to flow into the indoor unit (use side heat exchanger)
Implementation Method 2
the heat medium can store a given amount of heat capacity. That is, the heat medium functions as a buffer
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
An air-conditioning apparatus 100 is provided with a heat-source device 1 that supplies a refrigerant, a relay unit 3 that exchanges heat of a heat medium such as water or anti-freezing fluid supplied from the heat-source device 1 in an intermediate heat exchanger 15 and supplies the heat medium, an indoor unit 2 that exchanges heat between a use side heat exchanger 26 through which the heat medium supplied from the relay unit 3 flows and indoor air and performs cooling or heating in the indoor space, a controller that controls operations of the heat-source device 1, the relay unit 3 and the indoor unit 2, and a third temperature sensor 33 that detects the temperature of the heat medium flowing through the use side heat exchanger 26, and if an abnormality in at least one of the heat-source device 1 and the relay unit 3 is detected, the controller continues the operation of the indoor unit while the temperature detected by the third temperature sensor remains within a first predetermined temperature range.