Systems and methods for diagnosing a loss of capacity of a climate control system
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Climate control systems, such as HVAC systems, face challenges in diagnosing a loss of heating capacity due to factors like refrigerant loss or component malfunctions, leading to increased runtime of auxiliary heat sources beyond what is expected based on outdoor ambient conditions.
Innovation Solution
A method that compares the actual runtime of an auxiliary heat source over a plurality of time blocks with an expected runtime, which is calculated as a function of outdoor ambient temperature over a time-delay block, to detect any loss of heating capacity and issue alerts when the actual runtime exceeds the expected runtime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the auxiliary heat source runtime is monitored and compared with expected runtime based on outdoor ambient temperature, then the detection precision of heating capacity loss is improved, but the device complexity increases due to the need for data collection, storage, and comparison mechanisms
Solution Approach 1:
The controller performs multiple functions: it controls the auxiliary heat source operation, collects outdoor ambient temperature data, stores runtime data over multiple time blocks, calculates expected runtime based on temperature correlations, and compares actual vs. expected runtime to detect capacity loss. By consolidating these diverse functions into a single controller, the patent avoids the need for separate dedicated devices for each function, thereby improving detection precision while limiting the increase in device complexity.
2Measurement precision
If the expected runtime is calculated using outdoor ambient temperature over a time-delay block, then the measurement precision of auxiliary heat source runtime is improved, but the loss of time increases due to the time-delay block requirement
Solution Approach 1:
The controller pre-calculates and stores the correlation between outdoor ambient temperature and expected auxiliary heat source runtime during system commissioning or normal operation. This preliminary action creates a reference model that can be quickly compared against actual runtime during diagnosis, eliminating the need for real-time complex calculations and reducing the time delay required for accurate measurement.
Solution Approach 2:
The system uses a time-delay block that encompasses the full thermal response time of the building, ensuring that all relevant temperature effects are captured. While this may seem excessive, it guarantees that the expected runtime calculation accounts for all thermal inertia effects, thereby maximizing measurement precision without requiring even longer observation periods.
3Reliability
If the runtime of auxiliary heat source is summed over a plurality of time blocks, then the reliability of heating capacity loss diagnosis is improved, but the loss of time increases due to the extended monitoring period required
Solution Approach 1:
The controller divides the monitoring period into discrete time blocks and sums the auxiliary heat source runtime across these periodic intervals. This periodic approach allows the system to capture seasonal variations and typical usage patterns, improving diagnostic reliability by comparing actual runtime against expected runtime aggregated over multiple periods rather than relying on single-point measurements.
Data Source
AI summary
Methods and related systems for diagnosing a loss of capacity of a heating, ventilation, and air conditioning (HVAC) system are disclosed. In an embodiment, the method includes summing a runtime of an auxiliary heat source of the HVAC system over a plurality of time blocks. Additionally, the method includes summing an expected runtime of the auxiliary heat source over the plurality of time blocks. Further, the method includes comparing the runtime sum with the expected runtime sum, wherein the expected runtime for each of the plurality of time blocks is a function of an outdoor ambient temperature over a time-delay block beginning before the corresponding time block.