Air-Conditioning Valve Control for Pipe-Length Flow Equalization
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Solution Overview
Problem
In air-conditioning apparatuses using a heat medium, pipes of different lengths to indoor units result in varying pressure losses and flow rates, leading to unequal capacities among indoor units, affecting heating and cooling efficiency.
Innovation Solution
An air-conditioning apparatus with a heat-medium transfer device, indoor units, and a controller that adjusts the flow control valve opening degree based on pipe length to equalize capacities among indoor units by determining the valve opening-degree control range based on flow-passage resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If pipes of different lengths are used to connect the heat-medium transfer device to multiple indoor units, then the system can accommodate flexible installation configurations, but the pressure losses and flow rates become unequal, resulting in different capacities among indoor units
Solution Approach 1:
The patent applies local quality by setting different valve opening-degree control ranges for different indoor units based on their specific pipe lengths. Each indoor unit receives a customized control range tailored to its local condition (pipe length), allowing the system to accommodate flexible installation configurations while maintaining capacity uniformity across all units
Solution Approach 2:
The patent changes the control parameter (valve opening-degree control range) according to pipe length. By adjusting this parameter locally for each indoor unit, the system compensates for the different pressure losses caused by varying pipe lengths, thereby maintaining equal capacities despite installation flexibility
2Device complexity
If the valve opening-degree control range is set uniformly for all indoor units, then the control system is simple, but indoor units with different pipe lengths achieve different capacities, affecting heating and cooling performance
Solution Approach 1:
Instead of uniform control, the patent implements local quality by determining customized valve opening-degree control ranges for each indoor unit based on its pipe length. This localized approach maintains relatively simple control logic while achieving capacity uniformity across units with different installation conditions
Solution Approach 2:
The patent applies preliminary action by pre-determining the appropriate valve opening-degree control range for each indoor unit based on its pipe length before actual operation. This preliminary configuration allows the system to automatically maintain capacity uniformity without complex real-time adjustments, balancing simplicity with performance
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 solution ensures uniform flow rates and capacities among indoor units, even when pipes have different lengths, thereby maintaining consistent heating and cooling performance across all units.
Implementation Method 1
a pump provided to transfer a heat medium that contains water or brine and transfers heat
Implementation Method 2
an indoor heat exchanger provided to cause heat exchange to be performed between indoor air and the heat medium
Implementation Method 3
a flow control valve provided to adjust a flow rate of the heat medium that flows through the indoor heat exchanger
Data Source
AI summary
An air-conditioning apparatus includes: a heat-medium transfer device including a pump provided to transfer a heat medium that contains water or brine and transfers heat; a plurality of indoor units each of which includes an indoor heat exchanger provided to cause heat exchange to be performed between indoor air and the heat medium, and a flow control valve provided to adjust a flow rate of the heat medium that flows through the indoor heat exchanger, the plurality of indoor units being connected to the heat-medium transfer device by respective heat medium pipes; and a controller provided to control an opening degree of the flow control valve. The controller determines a valve opening-degree control range that is a control range of an opening degree of the flow control valve of each indoor unit, based on a flow-passage resistance depending on a length of a pipe that extends from the heat-medium transfer device to the indoor unit, such that the lower the flow-passage resistance, the smaller the valve opening-degree control range.