Air conditioner device and heat medium flow rate calculation method
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Solution Overview
Problem
Existing air-conditioning systems struggle to accurately estimate heat medium flow rates through use-side heat exchangers due to large pressure losses at pipes and branch portions, leading to inaccuracies in heat medium flow rate calculations.
Innovation Solution
An air-conditioning apparatus and method that includes a heat-source-side device, a pump, use-side heat exchangers, flow rate control devices, pressure sensors, and a controller. The controller performs operations to circulate the heat medium, opens and closes flow rate control devices in a predetermined pattern, and calculates flow rates using data from pressure sensors, enabling accurate estimation of heat medium flow rates even with significant pressure losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If flow rates are estimated from opening degrees of flow rate control devices, then the estimation method is simple, but the accuracy deteriorates when pressure losses at pipes and branch portions are large
Solution Approach 1:
The system performs preliminary calibration operations where flow rate control devices are individually opened/closed in a predetermined pattern to measure actual flow rates and pressure losses before normal operation. These measurements are stored as baseline data for subsequent accurate flow rate calculations during actual air conditioning operation.
Solution Approach 2:
The system uses pressure sensors to continuously monitor pressure at multiple locations and feeds this information back to the controller. The controller calculates flow rates based on pressure differences and stored calibration data, providing accurate real-time flow rate information that accounts for actual pressure losses in the system.
2Measurement precision
If pressure sensors are installed at multiple locations to measure pressure differences, then flow rate calculation accuracy improves, but device complexity and cost increase
Solution Approach 1:
The system divides the heat medium circuit into multiple measurement sections by installing pressure sensors at strategically selected locations (e.g., before and after branch portions). Each sensor location provides pressure data for specific circuit segments, enabling accurate flow rate calculation for individual use-side heat exchangers without requiring sensors throughout the entire system.
Solution Approach 2:
The system implements pressure measurement at key critical points rather than continuous measurement throughout the entire circuit. By measuring pressure at strategically chosen locations where pressure losses occur (branch portions, before/after heat exchangers), the system achieves sufficient accuracy for flow rate calculation without the excessive complexity of comprehensive pressure monitoring.
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 allows for precise estimation of heat medium flow rates through use-side heat exchangers, improving the accuracy of heat medium flow rate calculations and optimizing heat medium transport power, even in systems with substantial pressure losses.
Implementation Method 1
a heat-source-side device that heats or cools a heat medium serving as a medium that transfers heat
Implementation Method 2
a pump that sucks the heat medium and transfers the heat medium
Implementation Method 3
a plurality of use-side heat exchangers each of which causes heat exchange to be performed between the heat medium transferred by the pump and indoor air
Implementation Method 4
indoor-side pressure sensors each of which detects a pressure of the heat medium
Data Source
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AI summary
An air-conditioning apparatus includes: a heat-source-side device that heats or cools a heat medium; a pump that sucks and transfers the heat medium; use-side heat exchangers; a heat medium circuit including a common pipe at which the heat-source-side device and the pump are provided and parallel pipes branching off from the common pipe; flow rate control devices that control flow rates of the heat medium that passes through the heat exchangers; indoor-side pressure sensors that detect a pressure of the heat medium; a pump inlet-side pressure sensor and/or a pump outlet-side pressure sensor; a flow rate detection device that detects a pump flow rate; and a controller that performs a first operation in which the flow rate control devices are individually opened or closed and data regarding a flow passage resistance at a path related to each of the heat exchangers is obtained, and a second operation in which heat is supplied to indoor air, and calculates calculate flow rates of the heat medium that flows through the heat exchangers in the second operation, from pump flow rates and pressures detected by the pressure sensors in the first and second operations.