@article {2579, title = {Prevention of Compressor Short Cycling in Direct-Expansion (DX) Rooftop Units, Part 1: Theoretical Analysis and Simulation}, journal = {ASHRAE Transactions}, volume = {117}, year = {2011}, pages = {666-676}, author = {Xiufeng Pang and Mingsheng Liu} } @article {2580, title = {Prevention of Compressor Short Cycling in Direct-Expansion (DX) Rooftop Units{\textemdash} Part 2: Field Investigation}, journal = {ASHRAE Transactions}, volume = {117}, year = {2011}, pages = {677-685}, author = {Xiufeng Pang and Mingsheng Liu} } @article {249, title = {Impacts of Static Pressure Reset on VAV System Air Leakage, Fan Power, and Thermal Energy}, journal = {ASHRAE Transactions}, volume = {116}, year = {2010}, pages = {428-436}, author = {Mingsheng Liu and Jingjuan Feng and Zhan Wang and Keke Zheng and Xiufeng Pang} } @article {250, title = {CCLEP Reduces Energy Consumption by More than 50\% for a Luxury Shopping Mall}, journal = {ASHRAE Transactions}, volume = {115}, year = {2009}, pages = {492-501}, abstract = {

The Continuous Commissioning Leading Project (CCLEP) process is an ongoing process to apply system optimization theory and advanced technologies to commercial retrofit projects. It was developed by Liu et al (2006) through a U.S. Department of Energy grant to the University of Nebraska and the Omaha Public Power District (OPPD) for continuous commissioning applications in commercial retrofit projects. The CCLEP process, procedures and seven case study results have already been presented (Liu et al 2006).

CCLEP was applied to a luxury shopping mall and office building. The case study building has ten single fan dual-duct VAV AHUs, 123 dual-duct pneumatic controller pressure independent terminal boxes, and a central heating and cooling plant. Major retrofit efforts include upgrading pneumatic to DDC controls for all AHUs, installing main hot deck dampers, replacing the boiler, installing VFD on fans and pumps, and installing Fan Airflow Stations (FAS) and Pump Waterflow Stations (PWS). This paper presents the optimal control strategies, which include main hot deck damper control, supply fan control integrated with FAS, return fan control, optimal control for terminal boxes, chilled water temperature and chilled water pump speed control, hot water temperature and hot water pump control. The measured hourly utility data after CCLEP show that annual HVAC electricity consumption is reduced by 56\% and gas use is reduced by 36\%.

This paper demonstrates the energy savings and system performance improvement through retrofits and optimal system control. This paper will present the case study building information, CCLEP major retrofits, CCLEP optimal control strategies, CCLEP results and conclusions

}, author = {Lixia Wu and Mingsheng Liu and Xiufeng Pang and Gang Wang and Thomas G. Lewis} } @article {251, title = {Improving Control and Operation of a Single Duct VAV System through CCLEP}, journal = {ASHRAE Transactions}, volume = {115}, year = {2009}, month = {07/2009}, pages = {760-768}, abstract = {

With the energy crisis of the early 1970s came the realization that buildings could be made much more efficient without sacrificing comfort. Over the last 30 years, use of variable air volume systems has become common practice. Many variable air volume (VAV) systems with pneumatic controls were installed in the 1980s and are still in use. However, these systems often have outdated control strategies and deficient mechanical systems are deficient, which may cause occupant discomfort and excess energy consumption.

An ASHRAE committee proposed building commissioning in 1988 to ensure that system performance met design specifications. Continuous Commissioning (CC[R]) technology was developed and implemented in 1992. CC is an ongoing process to resolve operating problems, improve comfort, optimize energy use and identify retrofits for existing commercial and institutional buildings and central plant facilities [1-5]. Since 1999, the Energy Systems Laboratory (ESL) at the University of Nebraska has conducted extensive research to implement optimal system control during the design phase and finalize the optimal setpoints after system installation. ESL researchers have developed and implemented the Continuous Commissioning Leading Energy Project (CCLEP) process with federal and industry support. The CCLEP process has two stages: the contracting stage and the implementation stage. During the contracting stage, a comprehensive technical evaluation is performed. The CCLEP implementation stage involves planning, retrofit and trouble shooting, and optimization and follow-up. The CCLEP process, procedures and seven case study results are presented in [6].

This paper presents information on the case study facility, existing and improved control sequences, and building performance improvement and energy consumption measures before and after CCLEP implementation

}, author = {Young-Hum Cho and Mingsheng Liu and Xiufeng Pang} } @conference {252, title = {Economizer Control Using Mixed Air Enthalpy}, booktitle = {the 7th International Conference of Enhanced Building Operations}, series = {7th}, year = {2007}, month = {2007}, address = {San Francisco, CA}, author = {Jingjuan Feng and Mingsheng Liu and Xiufeng Pang} } @conference {254, title = {Integrated Static Pressure Reset with Fan Air Flow Station in Dual-duct VAV System Control}, booktitle = {ASME Energy Sustainability}, year = {2007}, month = {2007}, address = {Long Beach, CA}, author = {Lixia Wu and Mingsheng Liu and Gang Wang and Xiufeng Pang} } @conference {253, title = {VAV System Optimization through Continuous Commissioning in an Office Building}, booktitle = {the 7th International Conference of Enhanced Building Operations}, year = {2007}, month = {2007}, address = {San Francisco, CA}, author = {Young-Hum Cho and Xiufeng Pang and Mingsheng Liu} } @conference {255, title = {Case Study of Continuous Commissioning in an Office Building}, booktitle = {the 6th International Conference of Enhanced Building Operations}, year = {2006}, month = {2006}, address = {Shenzhen, China}, author = {Xiufeng Pang and Zheng, B and Mingsheng Liu} } @conference {257, title = {Building Pressure Control in VAV System with Relief Air Fan}, booktitle = {the 5th International Conference of Enhanced Building Operations}, year = {2005}, month = {2005}, address = {Pittsburgh, PA}, author = {Xiufeng Pang and Zheng, B and Mingsheng Liu} } @conference {258, title = {Continuous Commissioning of an Office Building}, booktitle = {the 5th International Conference of Enhanced Building Operations}, year = {2005}, month = {2005}, address = {Pittsburgh, PA}, author = {Zheng, B and Mingsheng Liu and Xiufeng Pang} } @conference {256, title = {Using a Fan Air Flow Station to Control Building Static Pressure in a VAV System}, booktitle = {the 2005 International Solar Energy Conference}, year = {2005}, month = {2005}, address = {Orlando, FL}, author = {Zheng, B and Xiufeng Pang and Mingsheng Liu} } @proceedings {304, title = {Use of Whole Building Simulation in On-Line Performance Assessment: Modeling and Implementation Issues}, journal = {Building Simulation {\textquoteright}01}, year = {2001}, month = {08/2001}, address = {Rio de Janeiro}, abstract = {

The application of model-based performance assessment at the whole building level is explored. The information requirements for a simulation to predict the actual performance of a particular real building, as opposed to estimating the impact of design options, are addressed with particular attention to common sources of input error and important deficiencies in most simulation models. The role of calibrated simulations is discussed. The communication requirements for passive monitoring and active testing are identified and the possibilities for using control system communications protocols to link on-line simulation and energy management and control systems are discussed. The potential of simulation programs to act as "plug-and-play" components on building control networks is discussed.

}, author = {Philip Haves and Tim I. Salsbury and David Claridge and Mingsheng Liu} }