Indoor Unit Temperature Slope Detection for HVAC Abnormal Operation
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Solution Overview
Problem
Existing air-conditioning apparatuses fail to effectively determine and address abnormal operations in multiple indoor units, leading to inefficient air-conditioning due to incorrect temperature readings caused by units affecting each other or operating based on incorrect temperature values.
Innovation Solution
An air-conditioning apparatus with suction temperature sensors, a storage unit, a timer, and a calculation unit that measures temperature change slopes to identify abnormal units by comparing these slopes with a determination threshold, allowing for individual control based on a designated parent unit's temperature readings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a representative temperature-related value is used to collectively control multiple indoor units, then the control system becomes simpler and switching between thermo-on and thermo-off states is coordinated, but the system fails to detect abnormal operations where individual units may be sensing incorrect temperatures due to mutual interference or installation issues
Solution Approach 1:
The patent divides the control system into two layers: individual unit monitoring (each unit independently measures its own suction temperature and calculates temperature change slope) and collective control (central controller coordinates based on representative values). This segmentation allows simultaneous detection of abnormal operations at the individual unit level while maintaining simplified collective control, resolving the contradiction between system simplicity and reliability.
2Ease of operation
If individual indoor units operate independently based on their own suction temperature sensors, then each unit can respond to local temperature conditions, but units may affect each other's temperature readings leading to incorrect operations when a large number of units are installed
Solution Approach 1:
The patent introduces feedback mechanisms where each indoor unit continuously monitors its suction temperature and calculates the temperature change slope. The central controller receives this data and identifies abnormal operations by comparing slopes against thresholds. This feedback loop enables the system to detect and correct measurement errors caused by mutual interference while preserving individual unit responsiveness to actual temperature conditions.
3Productivity
If the system uses a common representative temperature value for all indoor units, then coordinated switching between cooling and heating modes is achieved, but the system cannot identify which specific units are operating abnormally
Solution Approach 1:
The patent adds a new dimension of analysis by calculating the temperature change slope (rate of change over time) for each individual unit in addition to using the common representative temperature value. This additional dimensional information allows the system to maintain coordinated mode switching while simultaneously detecting abnormal operations, as abnormal units exhibit unusual temperature change slopes that differ from normal operational patterns.
Data Source
AI summary
An air-conditioning apparatus includes a plurality of indoor units each individually conditioning air in an air-conditioning target space, a storage unit storing detection values of a plurality of suction temperature sensors in time series, a timer measuring, for each of the plurality of indoor units, a preset temperature arrival period it takes for a suction temperature to reach a preset temperature for the air-conditioning target space after start of a thermo-on state or a thermo-off state, a calculation unit calculating, for each of the plurality of indoor units, a temperature change slope representing a change in the suction temperature for the preset temperature arrival period, and a determination unit comparing the temperature change slope of each of the plurality of indoor units with a determination threshold to determine, as an abnormal indoor unit, the indoor unit having the temperature change slope greater than the determination threshold.