Capacity staging system for multiple compressors
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Solution Overview
Problem
Current compressor control systems rely on single indoor sensors to estimate load, failing to accurately account for both indoor and outdoor factors, leading to inefficient operation and increased costs due to the need for multiple sensors and thermostats.
Innovation Solution
A capacity staging system that uses a mathematical model to predict compressor load based on outdoor ambient temperature and other building parameters, eliminating the need for indoor temperature sensors and thermostats by incorporating a sensible load determination unit that considers various building characteristics and relative humidity to control compressor output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensors and thermostats are used to accurately estimate compressor load, then measurement precision improves, but device complexity and cost increase
Solution Approach 1:
The patent extracts the load estimation function from physical sensors and thermostats, relocating it to a mathematical model that processes outdoor temperature data. This eliminates the need for multiple indoor sensors while maintaining accurate load estimation through calculated sensible and latent load components.
Solution Approach 2:
The patent replaces the mechanical sensor-based measurement system with a mathematical modeling approach. Instead of using physical thermostats and sensors to detect load conditions, the system uses computational models that calculate load based on outdoor temperature, building characteristics, and psychrometric relationships.
2Device complexity
If indoor temperature sensors and thermostats are eliminated to reduce cost and maintenance, then device complexity decreases, but measurement precision deteriorates
Solution Approach 1:
The patent introduces outdoor ambient temperature as an intermediary parameter that mediates between external conditions and compressor load estimation. By using outdoor temperature combined with building characteristics in mathematical models, the system indirectly determines indoor load conditions without requiring direct indoor temperature measurements.
Solution Approach 2:
The patent changes the fundamental parameters used for load estimation from indoor temperature readings to outdoor temperature combined with building envelope characteristics, occupancy, and equipment loads. This parameter transformation enables accurate load prediction through mathematical relationships rather than direct sensing.
3Ease of operation
If thermostat-based control is used to stage compressors, then ease of operation is maintained, but productivity and efficiency decrease due to inaccurate load estimation
Solution Approach 1:
The patent performs preliminary calculation of sensible and latent load components before compressor staging decisions are made. By pre-calculating the total cooling load based on outdoor temperature and building characteristics, the system enables more accurate and timely compressor capacity modulation, improving overall system efficiency while maintaining operational simplicity.
Data Source
AI summary
A control system for controlling an output for at least one compressor includes a control unit that receives an indoor set point and an outdoor ambient temperature. The control unit determines a load request based on the indoor set point and the outdoor ambient temperature without considering an indoor room temperature. The at least one compressor receives control commands from the control unit based on the load request.