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.

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.

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.

Development and Validation of Online Parameter Estimation for HVAC Systems

2002 ◽  
Author(s):  
Jin Wen ◽  
Theodore F. Smith
Keyword(s):  
Parameter Estimation ◽  
Thermal Load ◽  
Least Squares Method ◽  
Hvac Systems ◽  
Recursive Least Squares ◽  
Thermal Loads ◽  
Variable Air Volume ◽  
Improve Energy Efficiency ◽  
System Parameters ◽  
Occupant Comfort

Heating, ventilating, and air-conditioning systems of buildings consume nearly 50 percent of the world’s energy. To improve energy efficiency, to increase occupant comfort, and to provide better system operation and control 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 load for a building zone. In this study, the building zone and variable-air-volume unit are modeled. The system parameters including the thermal load are estimated using the recursive-least-squares method with variable forgetting factor. The sensitivity of the estimation results to different factors is examined. Different experiments are used to validate the estimation results. The comparisons between the experiments and the estimation results show good agreement.

Variable Air Volume System Application in Museums

2007 ◽  
Author(s):  
Zhan Wang ◽  
Bin Zheng ◽  
Wenlong Xu ◽  
Gang Wang ◽  
Mingsheng Liu
Keyword(s):  
Energy Consumption ◽  
System Control ◽  
Variable Air Volume ◽  
Heating And Cooling ◽  
Air Volume ◽  
Variable Frequency Drives ◽  
Air Handling Units ◽  
Simultaneous Heating ◽  
Simultaneous Heating And Cooling ◽  
Cooling Loads

Relative humidity and temperature control is key in museums, galleries, libraries and archives. Normally constant volume (CV) air handling units (AHUs) with reheat coils are applied in these buildings. Setting a low supply air temperature limits the highest humidity level; however, reheat coils have to be used to maintain space temperature due to constant supply airflow. As a result, simultaneous heating and cooling exists with excessive energy consumption. It is well known that variable air volume (VAV) technologies can reduce simultaneous heating and cooling as well as fan power. This paper presents the detail VAV system retrofit for the existing CV system, control sequence development and system performance evaluation in a museum facility at Omaha, Nebraska. Variable Frequency Drives (VFDs) were installed for the supply fan on the AHUs. Space humidity and temperature, heating and cooling energy consumption, and fan power were measured. The measurements showed that the space humidity and temperature was maintained within the required range under VAV operation while the reheat consumption was reduced by up to 85% and the fan power consumption was reduced by 90% under partial cooling loads.

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