Browsing by Author "O'Neill, Zheng D."

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    Assessing the validity, reliability, and practicality of ASHRAE's performance measurement protocols (ASHRAE Research Project 1702)
    (Taylor & Francis, 2019) Wang, Liping; Mcmorrow, Gabrielle; Zhou, Xiaohui; O'Neill, Zheng D.; University of Wyoming; University of Alabama Tuscaloosa
    The objective of this study was to provide a basis for future updates to the 2010 ASHRAE Performance Measurement Protocols for Commercial Buildings (PMP) through case studies. The PMP defines a standardized method of measuring and analyzing building performance in six categories: energy, water, thermal comfort, indoor air quality, lighting, and acoustics. We conducted case studies for five buildings following the PMP. Based on experiences following the protocol in this wide range of buildings, we assessed the validity, reliability, and practicality of the PMP and provided comments and recommendations for future revisions. Most of the measurement protocols at the basic level are reliable, practical, and valid. Many tasks at the intermediate and advanced levels, however, can be difficult to perform for some building types. Some of the tasks or measurement procedures were results from past research projects, and the software or tools recommended may not be readily available or fully supported. The measurement protocols at the intermediate level are only somewhat reliable and some of them are impractical. Most measurement protocols at the advanced level are complex and need to be performed by qualified or specially trained personnel and, thus, are impractical as a performance measure, except for specialized applications.
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    Development of control quality factor for HVAC control loop performance assessment-II: Field testing and results (ASHRAE RP-1587)
    (Taylor & Francis, 2019) Liu, Ran; Li, Yanfei; O'Neill, Zheng D.; Zhou, Xiaohui; University of Alabama Tuscaloosa; United States Department of Energy (DOE); National Renewable Energy Laboratory - USA
    This article is the third paper from the research project RP-1587, focusing on presenting a comprehensive field test of the proposed control quality factors (CQFs; i.e., CQF-Harris and CQF-exponentially weighted moving average [EWMA]) and testing results. Firstly, the simulated control loops and real control loops are evaluated for offline assessment. Then, the field experiment implemented for different HVAC control loops is assessed online using the proposed CQFs. Test results show that the proposed CQFs are capable of adequately and effectively assessing the HVAC control loop performance. The methodology of obtaining those CQFs is provided in the companion paper: Development of Control Quality Factor for HVAC Control Loop Performance Assessment I-Methodology (ASHRAE RP-1587) (Li et al. 2019).
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    Energy savings and ventilation performance from CO2-based demand controlled ventilation: Simulation results from ASHRAE RP-1747 (ASHRAE RP-1747)
    (Taylor & Francis, 2019) O'Neill, Zheng D.; Le, Yanfei; Cheng, Hwakong C.; Zhou, Xiaohui; Taylor, Steven T.; University of Alabama Tuscaloosa
    This is the first journal paper from the ASHRAE research project RP-1747 "Implementation of RP-1547 CO2-based Demand Controlled Ventilation for Multiple Zone HVAC Systems in Direct Digital Control Systems." HVAC designers face challenges in complying with the ventilation requirements in ASHRAE Standard 62.1 due to the complexity of the ventilation rate procedure (VRP) and the lack of direction on how to appropriately apply demand controlled ventilation (DCV) within the context of the VRP. The RP-1747 project aimed to address those issues by developing and testing DCV control sequences that are practical and implementable in typical single-duct variable air volume (VAV) systems with direct digital control (DDC) Systems. These control sequences were also tested for energy and ventilation performance by using a co-simulation of EnergyPlus and CONTAM coupled by a functional mockup unit (FMU). This paper presents the simulation-based study of one office building in four climate zones including Miami (1A), Atlanta (3A), Oakland (3C), and Chicago (5A) for both DCV and non-DCV baselines. The ventilation requirements in non-DCV baselines were set following a simplified ASHRAE 62.1 approach and California Title 24. Simulation results show that RP-1747 DCV control logic could lead to 9% to 33% HVAC energy savings on a source energy basis compared with the non-DCV baseline with the simplified ASHRAE 62.1 approach. The simulated hourly outdoor airflow provided met or exceeded the ASHRAE Standard 62.1 ventilation requirement in the four climate zones for 83% to 97% of the time for the simulated building. Transients and simulation artifacts associated with the discretization of time steps appear to account for a large portion of the time steps when the ventilation provided is less than required by the Standard. After applying a tolerance to account for sensor and control error in real life and time averaging as allowed by Standard 62.1, the DCV strategy met ventilation requirements for 96% to 98% of the time. This indicates the RP-1747 DCV control logic achieves good compliance with the ventilation requirements in Standard 62.1.