Multi-Compressor Capacity Staging for Linear HVAC Load Control
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Solution Overview
Problem
Traditional HVAC systems with multiple compressor circuits face inefficiencies due to non-linear capacity profiles, leading to sudden changes in cooling output and increased energy usage, discomfort for occupants, and reduced energy efficiency.
Innovation Solution
A customizable stage profiling modulation algorithm that determines a target system capacity profile, selects suitable compressor stages, and generates modulation information to control compressor operation based on load requests, ensuring a linear or substantially linear capacity profile across varying compressor arrangements and types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional non-linear capacity profiles are used in multi-compressor HVAC systems, then the system can handle varying load demands, but the cooling output changes suddenly and energy consumption increases
Solution Approach 1:
The patent implements dynamic compressor capacity modulation by continuously adjusting the capacity of individual compressors within a circuit based on real-time load demands. The system transitions from static on/off control to dynamic continuous modulation, allowing compressors to operate at optimal capacities matching the actual cooling demand, thereby eliminating sudden output changes and reducing energy waste during part-load conditions.
Solution Approach 2:
The system changes the operating parameters of compressors by modulating their capacity stages dynamically. Instead of fixed capacity operation, the control system adjusts compressor capacity parameters in response to load variations, selecting appropriate capacity stages to maintain linear cooling output progression and minimize energy consumption across the full operating range.
2Productivity
If multiple compressor circuits with multiple compressors each are used, then the system capacity can be increased, but the system complexity increases
Solution Approach 1:
The control system implements a universal capacity management algorithm that can handle any configuration of multiple compressor circuits with varying numbers of compressors per circuit. The single control system performs multiple functions: monitoring load demands, determining required system capacity, distributing capacity requirements across individual compressors, and modulating each compressor's operation. This multi-functional approach manages complexity while maximizing system capacity utilization.
3Loss of energy
If compressor capacity is modulated dynamically, then energy efficiency is improved, but the control system complexity increases
Solution Approach 1:
The control system implements self-service capacity management by autonomously determining the required system capacity based on load demands and automatically distributing this capacity across individual compressors. The system monitors its own operating conditions, calculates optimal capacity distribution, and executes modulation without external intervention. This self-managing capability achieves energy efficiency through continuous optimization while the embedded control logic handles the complexity internally.
Solution Approach 2:
The system employs feedback control mechanisms where the control system continuously monitors load demands, compares actual cooling output with target capacity, and adjusts compressor modulation accordingly. This closed-loop feedback ensures energy efficiency by maintaining optimal operating points while the automatic adjustment process manages control complexity through real-time corrections based on system performance.
Data Source
AI summary
A system is provided and includes a first controller, a non-transitory computer-readable medium and a second controller. The first controller is configured to control operation of at least one compressor circuit including one or more compressors. The non-transitory computer-readable medium is configured to store instructions of a stage profiler for execution by the controller. The instructions include: determining a target system capacity profile for the at least one compressor circuit; determining system stage capacities for stages of the at least one compressor circuit; selecting some of the system stage capacities based on the target system capacity profile to provide an available system capacity profile; generating modulation information based on the available system capacity profile and a load request signal; and controlling operation of the one or more compressors based on the modulation information and according to the available system capacity profile.