Heat-Medium Pump Switching in Air Conditioning Under Low Load
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Solution Overview
Problem
Existing air-conditioning systems face challenges such as increased energy consumption, potential refrigerant leaks, and pitting corrosion due to excessive heat medium flow rates, especially when the load in indoor units is small, leading to inefficiencies and safety concerns.
Innovation Solution
The air-conditioning apparatus incorporates a plurality of heat-medium conveying devices that can be controlled to reduce power consumption and flow rates, allowing for selective operation of pumps to maintain optimal flow and prevent corrosion, even when the load is small, by implementing pump rotation operation controls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple heat-medium conveying devices operate simultaneously, then the heat medium can be supplied to all indoor units, but the energy consumption increases and the flow rate becomes excessive causing pitting corrosion
Solution Approach 1:
The system dynamically adjusts the number of operating heat-medium conveying devices based on the load conditions. When the total load is small, fewer devices operate; when the load increases, more devices are activated. This dynamic configuration optimizes energy consumption while maintaining reliable heat medium supply to all required indoor units.
Solution Approach 2:
The system changes the operational parameters by adjusting the number of active heat-medium conveying devices according to load requirements. This parameter change allows the system to match the heat medium flow rate to the actual demand, preventing excessive flow rates that cause pitting corrosion while ensuring sufficient supply when needed.
2Reliability
If multiple heat-medium conveying devices operate simultaneously, then the heat medium can be supplied to all indoor units, but the flow rate becomes excessive causing pitting corrosion
Solution Approach 1:
The system dynamically adjusts the number of operating heat-medium conveying devices based on the load conditions. When the total load is small, fewer devices operate; when the load increases, more devices are activated. This dynamic configuration optimizes energy consumption while maintaining reliable heat medium supply to all required indoor units.
Solution Approach 2:
The system changes the operational parameters by adjusting the number of active heat-medium conveying devices according to load requirements. This parameter change allows the system to match the heat medium flow rate to the actual demand, preventing excessive flow rates that cause pitting corrosion while ensuring sufficient supply when needed.
3Adaptability or versatility
If the heat medium circulation path is extended to reach indoor units, then cooling or heating can be provided to multiple locations, but the conveying power required increases significantly
Solution Approach 1:
The system segments the heat medium circulation by using multiple independent heat-medium conveying devices, each serving specific indoor units. This segmentation allows the conveying power to be distributed across multiple smaller pumps rather than requiring one large pump to serve all distant units, reducing the total conveying power requirement while maintaining extended coverage.
Solution Approach 2:
The relay unit acts as an intermediary between the outdoor unit and indoor units. It receives refrigerant from the outdoor unit, performs heat exchange with the heat medium, and then distributes the heat medium to various indoor units. This intermediary structure enables extended coverage while managing conveying power requirements efficiently.
4Device complexity
If refrigerant is circulated directly to indoor units, then the system is compact, but refrigerant may leak into the room creating safety concerns
Solution Approach 1:
The relay unit serves as an intermediary that receives refrigerant from the outdoor unit and transfers heat to the heat medium without allowing the refrigerant to enter the indoor units. This intermediary structure maintains system compactness while preventing refrigerant leakage into rooms, thereby eliminating safety concerns associated with direct refrigerant circulation to indoor units.
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 reduces energy consumption, minimizes the risk of pitting corrosion, and enhances safety by optimizing the number of operating pumps based on load requirements, ensuring efficient and safe operation across various operation modes.
Implementation Method 1
a heat exchanger arranged inside an outdoor unit heats or cools water, antifreeze, or the like
Implementation Method 2
it is conveyed to a fan coil unit, panel heater, or the like, which is an indoor unit, and cooing or heating is performed
Data Source
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AI summary
In an air-conditioning apparatus 100, when a plurality of pumps 31 are all operating and a heat exchange amount in use-side heat exchangers 35 is equal to or lower than a lower limit of a thermal capacity that can be conveyed in a heat medium circuit B, before at least one of the plurality of pumps 31 is stopped, a refrigerant flow path in the intermediate heat exchanger 25 connected to the pump 31 that is to be stopped is closed. Then, the at least one of the plurality of pumps 31 is stopped, and the thermal capacity required in at least one of the use-side heat exchangers 35 in the rest of the plurality of pumps 31 is conveyed.