Regenerative air conditioner
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Solution Overview
Problem
Air conditioners face efficiency decline and comfort issues at low air-conditioning loads due to compressor operation at suboptimal speeds, leading to frequent on/off cycles and temperature fluctuations.
Innovation Solution
A thermal storage air conditioner that switches between simple cooling and cold thermal energy storage operations based on compressor speed, maintaining efficient operation by adjusting the refrigerant cycle to optimize compressor speed and reduce on/off cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the rotational speed of the compressor is reduced to match low air-conditioning load, then the air-conditioning capacity matches the load, but the compressor efficiency declines
Solution Approach 1:
The compressor maintains continuous operation at optimal rotational speed while the thermal storage medium absorbs excess cooling capacity. This prevents the compressor from cycling on/off or operating inefficiently at reduced speeds, ensuring continuous useful action and high efficiency while still matching the air-conditioning capacity to the actual load through thermal storage.
2Adaptability or versatility
If the compressor operates at low rotational speed to reduce capacity, then the capacity matches low load, but the on/off cycles increase and comfort deteriorates
Solution Approach 1:
The thermal storage medium acts as an intermediary between the compressor and the air-conditioning system. It absorbs the excess cooling capacity generated by the continuously operating compressor, preventing temperature fluctuations in the room and eliminating the need for on/off cycles, thus maintaining both capacity matching and temperature stability.
3Reliability
If the compressor runs at minimum speed continuously, then on/off cycles are eliminated, but the efficiency still declines at low load
Solution Approach 1:
The system discards the excess cooling capacity that would otherwise be wasted when the compressor runs at minimum speed during low load conditions. This excess capacity is recovered and stored in the thermal storage medium, which can later be utilized when cooling demand increases, thereby improving overall system efficiency while maintaining continuous compressor operation.
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 approach enhances compressor efficiency, reduces power consumption, and maintains room comfort by utilizing thermal energy storage effectively, even at low loads, thereby minimizing temperature variations and startup power requirements.
Implementation Method 1
a thermal storage section (60) which has a thermal storage medium and exchanges heat between the thermal storage medium and a refrigerant of the refrigerant circuit (11)
Implementation Method 2
in the refrigerant circuit (11), the refrigerant is condensed in the outdoor heat exchanger (23)
Implementation Method 3
the refrigerant is condensed in the outdoor heat exchanger (23) and evaporates in the indoor heat exchanger (72)
Implementation Method 4
a cooling and cold thermal energy storage operation in which in the refrigerant circuit (11), the refrigerant is condensed in the outdoor heat exchanger (23) and evaporates in the indoor heat exchanger (72), and in which the thermal storage medium in the thermal storage section (60) is cooled by the refrigerant
Data Source
Figure 1
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AI summary
To avoid decline in the efficiency of a compressor at a low load, a thermal storage air conditioner has a refrigerant circuit (11) which has a compressor (22), an outdoor heat exchanger (23), and an indoor heat exchanger (72) and performs a refrigeration cycle, and a thermal storage section (60) which has a thermal storage medium and exchanges heat between the thermal storage medium and a refrigerant of the refrigerant circuit (11). The thermal storage air conditioner performs a simple cooling operation in which in the refrigerant circuit (11), the refrigerant is condensed in the outdoor heat exchanger (23) and evaporates in the indoor heat exchanger (72), and a cooling and cold thermal energy storage operation in which in the refrigerant circuit (11), the refrigerant is condensed in the outdoor heat exchanger (23) and evaporates in the indoor heat exchanger (72), and in which the thermal storage medium in the thermal storage section (60) is cooled by the refrigerant. The thermal storage air conditioner has an operation control section (100) which, if a rotational speed of the compressor (22) is slowed down to a predetermined lower reference value in the simple cooling operation, switches an operation of the thermal storage air conditioner from the simple cooling operation to the cooling and cold thermal energy storage operation to increase the rotational speed of the compressor (22).