Bilinear model-based diagnosis of lock-in-place failures of variable-air-volume HVAC systems of multizone buildings

2020 ◽  
Vol 28 ◽  
pp. 101023
Author(s):  
Mona Subramaniam A ◽  
Tushar Jain ◽  
Joseph J. Yamé
Keyword(s):  
Hvac Systems ◽  
Bilinear Model ◽  
Variable Air Volume ◽  
Model Based ◽  
Air Volume ◽  
Lock In

Development and Validation of Online Parameter Estimation for HVAC Systems

2003 ◽  
Vol 125 (3) ◽  
pp. 324-330 ◽  
Author(s):  
Jin Wen ◽  
Theodore F. Smith
Keyword(s):  
Energy Efficiency ◽  
Parameter Estimation ◽  
Hvac Systems ◽  
Recursive Least Squares ◽  
Volume Discharge ◽  
Thermal Loads ◽  
Variable Air Volume ◽  
Improve Energy Efficiency ◽  
System Parameters ◽  
Air Volume

Improving the energy efficiency of buildings by examining their heating, ventilating, and air-conditioning (HVAC) systems represents an opportunity. To improve energy efficiency, to increase occupant comfort, and to provide better system operation and control algorithms for these systems, online estimation of system parameters, including system thermophysical parameters and thermal loads, is desirable. Several reported studies have presented simulation results and assumed that the thermal loads are known. A difficulty in HVAC system parameter estimation is that most HVAC systems are nonlinear, have multiple and time varying parameters, and require an estimate of the thermal loads for a building zone. In this study, building zones and variable-air-volume units are modeled. The system parameters including the thermal loads are estimated using the recursive-least-squares method with a variable forgetting factor. The sensitivity of the estimation results to different factors is examined. The estimated parameters are used to predict the zone and variable-air-volume-discharge-air temperatures. Several experiments are used to validate the prediction results. The comparisons show good agreement between the experiments and the prediction results.

scholarly journals A review of common human errors in design, installation, and operation of multiple-zone VAV AHU systems

2021 ◽  
Vol 2042 (1) ◽  
pp. 012130
Author(s):  
Narges Torabi ◽  
H. Burak Gunay ◽  
William O’Brien
Keyword(s):  
Hvac Systems ◽  
Review Of The Literature ◽  
Human Errors ◽  
Variable Air Volume ◽  
Air Volume ◽  
Air Handling Units ◽  
Occupant Comfort ◽  
Building Life Cycle ◽  
The Impact ◽  
Design Construction

Abstract Faults in air-based heating, ventilation, and air conditioning (HVAC) systems lead to energy waste and discomfort. While the emphasis of fault detection and diagnostic (FDD) research has been on hard faults in actuators, sensors, and equipment, faults arising from human errors account for a significant portion of faults occurring in HVAC systems. In this paper, human errors occurring in air handling units (AHUs) and variable air volume (VAV) thermal zones during design, construction, and operation phases are identified through a review of the literature. Then, the faults are divided into six main categories. Based on case studies investigating these faults, the impact of each fault category on occupant comfort, energy consumption, and equipment life is discussed. The authors provide recommendations to minimize human errors in AHUs and VAV zones throughout the building life cycle.

Directing Supervisory Control Towards Real HVAC System Integration

2011 ◽  
Author(s):  
Aaron P. Wemhoff ◽  
William Flaherty
Keyword(s):  
Energy Consumption ◽  
Supervisory Control ◽  
System Integration ◽  
Energy Savings ◽  
Hvac Systems ◽  
Control Approach ◽  
Variable Air Volume ◽  
Air Volume ◽  
Transient System ◽  
Mc Method

Heating, ventilating, and air conditioning (HVAC) systems comprise a significant portion of U. S. energy consumption. A supervisory control approach allows for the reduction of HVAC energy used. The authors previously developed and discussed the Master Controller (MC) method as a type of supervisory control that minimizes HVAC energy consumption for a given system. This paper provides two advancements towards the application of the MC method in a real system. First, airflow constraints are incorporated into the MC algorithm. Second, an approach is developed for incorporating transient system loads that are calculated via commercial software. The constrained MC method is shown to produce energy savings of approximately 40% compared to a traditional Variable Air Volume (VAV) method and VAV method with chiller control for reducing HVAC energy consumption for an example system.

scholarly journals A Multi-Timescale Bilinear Model for Optimization and Control of HVAC Systems with Consistency

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 400 ◽  
Author(s):  
Zelin Nie ◽  
Feng Gao ◽  
Chao-Bo Yan
Keyword(s):  
Optimization Model ◽  
Air Conditioning ◽  
State Of The Art ◽  
Hvac Systems ◽  
Practical Significance ◽  
Hvac System ◽  
Bilinear Model ◽  
Optimization And Control ◽  
And Control ◽  
Slow Timescale

Reducing the energy consumption of the heating, ventilation, and air conditioning (HVAC) systems while ensuring users’ comfort is of both academic and practical significance. However, the-state-of-the-art of the optimization model of the HVAC system is that either the thermal dynamic model is simplified as a linear model, or the optimization model of the HVAC system is single-timescale, which leads to heavy computation burden. To balance the practicality and the overhead of computation, in this paper, a multi-timescale bilinear model of HVAC systems is proposed. To guarantee the consistency of models in different timescales, the fast timescale model is built first with a bilinear form, and then the slow timescale model is induced from the fast one, specifically, with a bilinear-like form. After a simplified replacement made for the bilinear-like part, this problem can be solved by a convexification method. Extensive numerical experiments have been conducted to validate the effectiveness of this model.

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