Experimental and Computational Investigations of the Thermal Environment in a Small Operational Data Center for Potential Energy Efficiency Improvements

Abstract The share of equipment and power use in smaller data centers (DCs) is comparable with that of more massive counterparts. However, they grabbed less attention in the literature despite being less energy-efficient. This study highlights the challenges of setting up a computational fluid dynamics (CFD) model of a 180-m2 small-size high-performance computing (HPC) DC and the validation procedure leading to a reasonably accurate model for the investigation of the thermal environment and potential energy efficiency improvements. Leaky floors, uneven placement of computing equipment and perforated tiles preventing separation of hot and cold air, low-temperature operation, and excessive cooling capacity and fan power were identified sources of energy inefficiency in the DC. Computational fluid dynamics model predictions were gradually improved by using experimental measurements for various boundary conditions (BCs) and detailed geometrical representation of large leakage openings. Eventually, the model led to predictions with an error of less than 1 °C at the rack inlet and less than 5 °C at the rack outlet. The ultimate objective was to use the validated CFD model to test various energy efficiency measures in the form of operational or design changes in line with the best practices. Impact of leakage between the raised floor and the room, reduced airflow rate, cold-aisle and hot-aisle separation, workload consolidation, and higher temperature operation were among the phenomena tested by using the validated CFD model. The estimated power usage effectiveness (PUE) value reduced from 1.95 to 1.40 with the proposed energy efficiency measures.

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Thermal Profiling of a Small Operational Data Center

ASME 2019 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems ◽

10.1115/ipack2019-6309 ◽

2019 ◽

Author(s):

İsmail Türkmen ◽

Cem Ahmet Mercan ◽

Hamza Salih Erden

Keyword(s):

Energy Efficiency ◽

Boundary Conditions ◽

Data Center ◽

High Performance ◽

Performance Indicator ◽

Thermal Environment ◽

Airflow Rate ◽

Cfd Model ◽

Energy Efficiency Measures ◽

Efficiency Measures

Abstract This study highlights experimental challenges of setting up a computational fluid dynamics (CFD) model of a 180-m2 small-size high-performance computing (HPC) data center (DC) in a university campus and the validation procedure leading to a reasonably accurate CFD model for the investigation of the thermal environment. Experimental results based on temperature, airflow, pressure, and power measurements help to confirm and identify inefficient design and operational practices as well as problematic areas regarding the thermal management, define the boundary conditions and validate CFD models. Leaky floors, uneven placement of computing equipment and perforated tiles preventing separation of hot and cold air, low-temperature operation, excessive cooling capacity and fan power were identified sources of energy inefficiency in the DC. CFD model predictions were gradually improved by using experimental measurements in various boundary conditions and detailed geometrical representation of large leakage openings. The performance indicator of the CFD model during the validation process was the temperature prediction error at the rack inlets and exits. After all improvements, the CFD model can make estimations with an error less than 1°C (RMSE < 1.0) at the rack inlet and less than 5°C (RMSE < 5.0) at the rack outlet. The validated CFD model tests the feasibility of various energy efficiency measures. These measures are in the form of operational or design changes in line with the best practices. Impact of leakage between the raised floor and the room, reduced airflow rate, cold-aisle and hot-aisle separation, workload consolidation, and higher temperature operation were among the phenomena tested by using the validated CFD model. The estimated power usage effectiveness (PUE) value reduced from 1.95 to 1.40 with the implemented energy efficiency measures.

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Energieeffizienz von lufttechnischen Anlagen/Energy efficiency of HVAC systems - Case study of the ETA transfer project in the machining industry

wt Werkstattstechnik online ◽

10.37544/1436-4980-2021-01-02-35 ◽

2021 ◽

Vol 111 (01-02) ◽

pp. 31-36

Author(s):

Lars Petruschke ◽

Max Burkhardt ◽

Benedikt Grosch ◽

Thomas Kohne ◽

Matthias Weigold ◽

...

Keyword(s):

Energy Efficiency ◽

Potential Energy ◽

Air Conditioning ◽

Energy Optimization ◽

Hvac Systems ◽

Energy Efficiency Measures ◽

Efficiency Measures ◽

Supply Systems

Im Projekt ETA-Transfer werden Produktionsanlagen sowie die entsprechenden versorgungstechnischen Anlagen hinsichtlich energetischer Optimierungspotenziale untersucht. Bei sieben Unternehmen werden die jeweiligen lufttechnischen Anlagen analysiert. Hierzu werden Mess- und Unternehmensdaten erhoben, um dann mittels Simulationen potenzielle Energieeffizienzmaßnahmen bewerten zu können. Insgesamt wird in der Fallstudie ein CO2-Einsparpotenzial von circa 870 t/a identifiziert.   The ETA transfer project investigates production plants as well as the corresponding technical supply systems regarding their potential for energy optimization. The heating, ventilation and air conditioning (HVAC) systems of seven companies are analyzed. For this purpose, measurement and company data is collected to simulate and evaluate potential energy efficiency measures. The case study identifies a CO2 savings potential totalling approximately 870 t/a.

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Impact of Passive Energy Efficiency Measures on Cooling Energy Demand in an Architectural Campus Building in Karachi, Pakistan

Sustainability ◽

10.3390/su13137251 ◽

2021 ◽

Vol 13 (13) ◽

pp. 7251

Author(s):

Mushk Bughio ◽

Muhammad Shoaib Khan ◽

Waqas Ahmed Mahar ◽

Thorsten Schuetze

Keyword(s):

Energy Efficiency ◽

Energy Demand ◽

Electricity Consumption ◽

Information Modeling ◽

Base Case ◽

Energy Efficiency Measures ◽

Efficiency Measures ◽

The Impact ◽

Cooling Energy Demand ◽

Campus Building

Electric appliances for cooling and lighting are responsible for most of the increase in electricity consumption in Karachi, Pakistan. This study aims to investigate the impact of passive energy efficiency measures (PEEMs) on the potential reduction of indoor temperature and cooling energy demand of an architectural campus building (ACB) in Karachi, Pakistan. PEEMs focus on the building envelope’s design and construction, which is a key factor of influence on a building’s cooling energy demand. The existing architectural campus building was modeled using the building information modeling (BIM) software Autodesk Revit. Data related to the electricity consumption for cooling, building masses, occupancy conditions, utility bills, energy use intensity, as well as space types, were collected and analyzed to develop a virtual ACB model. The utility bill data were used to calibrate the DesignBuilder and EnergyPlus base case models of the existing ACB. The cooling energy demand was compared with different alternative building envelope compositions applied as PEEMs in the renovation of the existing exemplary ACB. Finally, cooling energy demand reduction potentials and the related potential electricity demand savings were determined. The quantification of the cooling energy demand facilitates the definition of the building’s electricity consumption benchmarks for cooling with specific technologies.

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Design of Road-Side Barriers to Mitigate Air Pollution near Roads

Applied Sciences ◽

10.3390/app11052391 ◽

2021 ◽

Vol 11 (5) ◽

pp. 2391

Author(s):

Jose I. Huertas ◽

Javier E. Aguirre ◽

Omar D. Lopez Mejia ◽

Cristian H. Lopez

Keyword(s):

Fluid Dynamics ◽

Air Pollution ◽

Computational Fluid Dynamics ◽

Sulfur Hexafluoride ◽

Computational Domain ◽

Cfd Model ◽

Near Surface ◽

The Road ◽

Pollutant Concentrations ◽

Highly Correlated

The effects of using solid barriers on the dispersion of air pollutants emitted from the traffic of vehicles on roads located over flat areas were quantified, aiming to identify the geometry that maximizes the mitigation effect of air pollution near the road at the lowest barrier cost. Toward that end, a near road Computational Fluid Dynamics (NR-CFD) model that simulates the dispersion phenomena occurring in the near-surface atmosphere (<250 m high) in a small computational domain (<1 km long), via Computational Fluid Dynamics (CFD) was used. Results from the NR-CFD model were highly correlated (R2 > 0.96) with the sulfur hexafluoride (SF6) concentrations measured by the US-National Oceanic and Atmospheric Administration (US-NOAA) in 2008 downwind a line source emission, for the case of a 6m near road solid straight barrier and for the case without any barrier. Then, the effects of different geometries, sizes, and locations were considered. Results showed that, under all barrier configurations, the normalized pollutant concentrations downwind the barrier are highly correlated (R2 > 0.86) to the concentrations observed without barrier. The best cost-effective configuration was observed with a quarter-ellipse barrier geometry with a height equivalent to 15% of the road width and located at the road edge, where the pollutant concentrations were 76% lower than the ones observed without any barrier.

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