HVAC Precooling Control Using Aggregated Multi-Zone MPC

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Solution Overview

Problem

Model predictive control for building precooling faces challenges due to simplifications in weather forecasting errors and complexity in multi-zone optimization, leading to potential comfort limit exceedances with critical consequences for retail and residential buildings.

Innovation Solution

An aggregated single-zone model predictive control (MPC) method is formulated to aggregate multiple zones, determine optimal actions, simulate indoor quality trajectories, and set zone temperature setpoints to comply with comfort limits, using zone weighting and disaggregation techniques to minimize temperature differences and changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple zones are optimized separately using model predictive control, then each zone can maintain its comfort limits, but the computational complexity increases significantly

Engineering Contradiction:

Improvecomfort limit complianceVSAvoidcomputational complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple zone optimizations into a single aggregated optimization problem. Instead of solving separate MPC problems for each zone, the invention merges them into one unified problem that considers all zones simultaneously, reducing computational complexity while maintaining comfort limit compliance through aggregated constraints

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent segments the computational problem by separating the aggregation phase from the disaggregation phase. First, zones are aggregated into a single representative zone for optimization. Then, the optimal control actions are disaggregated back to individual zones for implementation, allowing complex multi-zone optimization to be solved through simpler sequential steps

Inventive Principle:

Principle #1Segmentation

2Productivity

If simplified weather forecasts are used in model predictive control, then computational speed increases, but accuracy of temperature prediction decreases leading to comfort limit exceedances

Engineering Contradiction:

Improvecomputational speedVSAvoidtemperature prediction accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent changes the parameters of the weather forecast model by aggregating multiple detailed weather parameters into a single representative temperature trajectory for the aggregated zone. This simplification maintains computational speed while the aggregation process preserves the essential thermal behavior needed for accurate prediction and comfort compliance

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9625171B2Optimized precooling of structures

Publication Date: 2017.04.18 HONEYWELL INTERNATIONAL INC

AI summary

A method includes aggregating multiple zones of an indoor structure, each zone having associated comfort limits, formulating an aggregated single zone model predictive control (MPC) problem representative of the multiple zones for a heating ventilation and air conditioning (HVAC) system, determining optimal aggregated actions as a function of the aggregated single zone model predictive control problem, simulating an optimal trajectory of indoor qualities, and determining zone temperature setpoints to comply with the comfort limits for each zone and pre-cool the indoor structure.