Wednesday, June 28, 2017: 11:00 AM-12:30 PM
HVAC&R Systems and Equipment
Chair:
Steven Taylor, P.E., Taylor Engineering LLC
Commonly, buildings exceeding the plant static pressure level experience negative pressure in their tallest parts, allowing air into the system that reduces heat transfer efficiency, causes noise, increases corrosion and consumes much more pumping power. One study sets out to investigate the effect of the wind speed and direction on cooling towers thermal performance. More than 40% of the data center energy consumption is attributed to the cooling system, majority of the CWS are overdesigned to accommodate the maximum projected heat load. A decentralized pumping system is an alternative system that only circulates the minimum water required by the respective terminal unit and can reduce excess pressure loss associated with centralized pumping systems.
1 Comparison of the Energy Saving Potential between Centralized and Decentralized Pumping Systems under Various Flow Conditions (LB-17-C068)
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Mingzhe Liu, University of Tokyo
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Ryozo Ooka, Ph.D., University of Tokyo
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Wonjun Choi, Ph.D., University of Tokyo
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Shintaro Ikeda, University of Tokyo
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In most HVAC systems, water is usually delivered by several centralized pumps, which may reduce the pumping system’s energy efficiency because of unnecessary pressure loss. A decentralized pumping system is an alternative system that only circulates the minimum water required by the respective terminal unit and can reduce the excess pressure loss. This paper verifies the performance of the decentralized pumping system by conducting an experiment comparing centralized and decentralized pump systems under various water flow conditions in terms of their energy consumption in water delivery and their energy saving potential.
2 CFD Investigation on Parameters Affecting the Thermal Performance of Mechanical Draft Cooling Towers in District Cooling Plants (LB-17-C069)
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E. M. ElBialy, Ph.D., Cairo University
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Essam E. Khalil, Cairo University
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District cooling means producing cooled water in a centralized plant and distributing it in pipelines to a number of buildings to cool the air in each building’s air conditioning system. This paper investigates the effect of the wind speed and direction on cooling towers' thermal performance. Moreover, the distance between stacks, cooling tower fan speed, and effect of wind barriers were also simulated. A three-dimensional Computational Fluid Dynamics (CFD) model of a power plant cooling towers is utilized to assess the effect of flow circulation air on entering air wet bulb temperature under different ambient conditions and orientations.
3 Large Campus Loop Performance Improvement, Negative Pressure Issue (LB-17-C070)
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Robert Henry, P.E., Texas A&M University
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Hui Chen, P.E., Texas A&M University
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Homer Bruner, Texas A&M University
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Klayton Wittler, Texas A&M University
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Elijah Crosby, Texas A&M University
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James Riley, Texas A&M University
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Texas A&M University’s Main campus has its heating and cooling district to provide needs of both heating hot water (HHW) and chilled water (CHW) to over 230 buildings. Commonly, buildings exceeding the plant static pressure level experience negative pressure in their tallest parts, allowing air into the system that reduces heat transfer efficiency, causes noise, and increases corrosion. The negative pressure also results in consuming much more pumping power due to the requirement of lifting water above plant static pressure to above top building coil. This paper identifies the reason for the negative pressure, and a pressure distribution analysis was performed on the campus thermal loop.
4 Evaluating and Improving the Chilled Water System of a Data Center Using Flow Network Modeling (LB-17-C071)
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Amir Radmehr, Ph.D., Innovative Research, Inc.
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John Fitzpatrick, University of Rochester
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Kanchan Kelkar, Ph.D., Innovative Research, LLC
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Chiller plants are commonly used to provide cooling water to data centers. While chiller plants are designed for the maximum projected heat load, majority of data centers produce a fraction of the design load. Chiller plants that operate at partial load may not perform efficiently. Evaluating the performance of a working chiller plant is challenging because of the limited data available at the site. Moreover, it is not possible to know how the system will perform after making an adjustment to improve the efficiency. This paper illustrates the use of a scientific approach based on the Flow Network Modeling (FNM) technique for improving the operating efficiency of a real-life data center in Rochester, NY.
