scholarly journals Analysis of methods for assessing the energy efficiency of data centers using the power usage effectiveness method

2022 ◽  
Vol 1216 (1) ◽  
pp. 012014
Author(s):  
R Uanov ◽  
A S Begimbetova
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Data Centers ◽  
Cooling System ◽  
Assessment Method ◽  
Vapor Compression ◽  
Compression Cycle ◽  
Free Cooling ◽  
Power Usage Effectiveness ◽  
Machine Room

Abstract The article deals with the analysis of methods for assessing the energy efficiency of data centers according to the Power Usage Effectiveness method. The demand for data centers which consumes a large amount of electricity is growing with the growth of digitalization and the accumulation of big data in the network. The energy consumption of the cooling system for the machine room accounts for a significant part of the operating costs of the building. Free cooling in a refrigeration system reduces energy consumption much more than operating systems with a vapor-compression cycle. In 2006 according to The Green Grid, the assessment method of Power Usage Effectiveness has become an international standard for measuring energy efficiency and is widely used in the design and operation of data centers. In this regard, the operation principles of free-cooling chillers are considered. The calculation example of the system payback in free-cooling is also given.

EnergIT

2013 ◽  
Vol 4 (1) ◽  
pp. 83-111 ◽  
Author(s):  
Eugenio Capra ◽  
Paolo Cremonesi ◽  
Chiara Francalanci ◽  
Francesco Merlo ◽  
Nicola Parolini
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Data Centers ◽  
Cooling System ◽  
Increase Energy Efficiency ◽  
Incremental Approach ◽  
Flow Circulation ◽  
System 2 ◽  
Reduction Of Energy Consumption

Researches on green data centers have defined guidelines and end-to-end methodologies to increase energy efficiency. Most of these approaches require a disrupting reengineering of the infrastructure and significant upfront investments. Smaller data centers need to reach green objectives with a more incremental approach. The EnergIT project proposes a methodology and related tools that support the incremental redesign of data centers toward greater energy efficiency based on three main levers: 1) physical repositioning of servers to optimize air flow circulation and cooling, enabling higher set temperatures of the cooling system; 2) replacement of server models; and 3) virtualization. This paper describes the approach and provides evidence on the effectiveness of the methodology by showing how the combined effect of the three levers has led to 62% reduction of energy consumption in a real case study.

Characterization of an Isolated Hybrid Cooled Server With Failure Scenarios Using Warm Water Cooling

2017 ◽  
Author(s):  
Uschas Chowdhury ◽  
Manasa Sahini ◽  
Ashwin Siddarth ◽  
Dereje Agonafer ◽  
Steve Branton
Keyword(s):  
Energy Consumption ◽  
Data Centers ◽  
Cooling System ◽  
Warm Water ◽  
Alternative Methods ◽  
Inlet Temperature ◽  
Cooling Efficiency ◽  
Water Cooling ◽  
Liquid Cooling ◽  
Total Energy Consumption

Modern day data centers are operated at high power for increased power density, maintenance, and cooling which covers almost 2 percent (70 billion kilowatt-hours) of the total energy consumption in the US. IT components and cooling system occupy the major portion of this energy consumption. Although data centers are designed to perform efficiently, cooling the high-density components is still a challenge. So, alternative methods to improve the cooling efficiency has become the drive to reduce the cooling cost. As liquid cooling is more efficient for high specific heat capacity, density, and thermal conductivity, hybrid cooling can offer the advantage of liquid cooling of high heat generating components in the traditional air-cooled servers. In this experiment, a 1U server is equipped with cold plate to cool the CPUs while the rest of the components are cooled by fans. In this study, predictive fan and pump failure analysis are performed which also helps to explore the options for redundancy and to reduce the cooling cost by improving cooling efficiency. Redundancy requires the knowledge of planned and unplanned system failures. As the main heat generating components are cooled by liquid, warm water cooling can be employed to observe the effects of raised inlet conditions in a hybrid cooled server with failure scenarios. The ASHRAE guidance class W4 for liquid cooling is chosen for our experiment to operate in a range from 25°C – 45°C. The experiments are conducted separately for the pump and fan failure scenarios. Computational load of idle, 10%, 30%, 50%, 70% and 98% are applied while powering only one pump and the miniature dry cooler fans are controlled externally to maintain constant inlet temperature of the coolant. As the rest of components such as DIMMs & PCH are cooled by air, maximum utilization for memory is applied while reducing the number fans in each case for fan failure scenario. The components temperatures and power consumption are recorded in each case for performance analysis.

The Steady-State Modeling and Analysis of a Two-Loop Cooling System for High Heat Flux Removal

2009 ◽  
Author(s):  
Rongliang Zhou ◽  
Juan Catano ◽  
Tiejun Zhang ◽  
John T. Wen ◽  
Greg J. Michna ◽  
...  
Keyword(s):  
Heat Flux ◽  
Steady State ◽  
Heat Exchangers ◽  
Cooling System ◽  
High Heat ◽  
System Structure ◽  
High Heat Flux ◽  
Vapor Compression ◽  
Vapor Compression Cycle ◽  
Compression Cycle

Steady-state modeling and analysis of a two-loop cooling system for high heat flux removal applications are studied. The system structure proposed consists of a primary pumped loop and a vapor compression cycle (VCC) as the secondary loop to which the pumped loop rejects heat. The pumped loop consists of evaporator, condenser, pump, and bladder liquid accumulator. The pumped loop evaporator has direct contact with the heat generating device and CHF must be higher than the imposed heat fluxes to prevent device burnout. The bladder liquid accumulator adjusts the pumped loop pressure level and, hence, the subcooling of the refrigerant to avoid pump cavitation and to achieve high critical heat flux (CHF) in the pumped loop evaporator. The vapor compression cycle of the two-loop cooling system consists of evaporator, liquid accumulator, compressor, condenser and electronic expansion valve. It is coupled with the pumped loop through a fluid-to-fluid heat exchanger that serves as both the vapor compression cycle evaporator and the pumped loop condenser. The liquid accumulator of the vapor compression cycle regulates the cycle active refrigerant charge and provides saturated vapor to the compressor at steady state. The heat exchangers are modeled with the mass, momentum, and energy balance equations. Due to the projected incorporation of microchannels in the pumped loop to enhance the heat transfer in heat sinks, the momentum equation, rarely seen in previous refrigeration system modeling efforts, is included to capture the expected significant microchannel pressure drop witnessed in previous experimental investigations. Electronic expansion valve, compressor, pump, and liquid accumulators are modeled as static components due to their much faster dynamics compared with heat exchangers. The steady-state model can be used for static system design that includes determining the total refrigerant charge in the vapor compression cycle and the pumped loop to accommodate the varying heat load, sizing of various components, and parametric studies to optimize the operating conditions for a given heat load. The effect of pumped loop pressure level, heat exchangers geometries, pumped loop refrigerant selection, and placement of the pump (upstream or downstream of the evaporator) are studied. The two-loop cooling system structure shows both improved coefficient of performance (COP) and CHF overthe single loop vapor compression cycle investigated earlier by authors for high heat flux removal.

Rechargeable Personal Air Conditioning Device

2016 ◽  
Author(s):  
Yilin Du ◽  
Jan Muehlbauer ◽  
Jiazhen Ling ◽  
Vikrant Aute ◽  
Yunho Hwang ◽  
...  
Keyword(s):  
Air Conditioning ◽  
Cooling System ◽  
Cooling Capacity ◽  
Comfort Level ◽  
Vapor Compression ◽  
Air Conditioning System ◽  
System A ◽  
Single Person ◽  
Vapor Compression Cycle ◽  
Compression Cycle

A rechargeable personal air-conditioning (RPAC) device was developed to provide an improved thermal comfort level for individuals in inadequately cooled environments. This device is a battery powered air-conditioning system with the phase change material (PCM) for heat storage. The condenser heat is stored in the PCM during the cooling operation and is discharged while the battery is charged by using the vapor compression cycle as a thermosiphon loop. The conditioned air is discharged towards a single person through adjustable nozzle. The main focus of the current research was on the development of the cooling system. A 100 W cooling capacity prototype was designed, built, and tested. The cooling capacity of the vapor compression cycle measured was 165.6 W. The PCM was recharged in nearly 8 hours under thermosiphon mode. When this device is used in the controlled built environment, the thermostat setting can be increased so that building air conditioning energy can be saved by about 5–10%.

scholarly journals Modelling and control of a free cooling system for Data Centers

2017 ◽  
Vol 140 ◽  
pp. 447-457 ◽  
Author(s):  
Alessandro Beghi ◽  
Luca Cecchinato ◽  
Giuseppe Dalla Mana ◽  
Michele Lionello ◽  
Mirco Rampazzo ◽  
...  
Keyword(s):  
Data Centers ◽  
Cooling System ◽  
Free Cooling ◽  
And Control

Optimization of Energy Consumption Using BIM-Based Building Energy Performance Analysis

2013 ◽  
Vol 281 ◽  
pp. 649-652 ◽  
Author(s):  
Dae Kyo Jung ◽  
Dong Hwan Lee ◽  
Joo Ho Shin ◽  
Byung Hun Song ◽  
Seung Hee Park
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Performance Analysis ◽  
Cooling System ◽  
Optimization Technique ◽  
Building Energy ◽  
Energy Performance ◽  
Information Modeling ◽  
Building Energy Performance ◽  
Heating And Cooling

Recently, the interest in increasing energy efficiency of building energy management system (BEMS) has become a high-priority and thus the related studies also increased. In particular, since the energy consumption in terms of heating and cooling system takes a large portion of the energy consumed in buildings, it is strongly required to enhance the energy efficiency through intelligent operation and/or management of HVAC (Heating, Ventilation and Air Conditioning) system. To tackle this issue, this study deals with the BIM (Building Information Modeling)-based energy performance analysis implemented in Energyplus. The BIM model constructed at Revit is updated at Design Builder, adding HVAC models and converted compatibly with the Energyplus environment. And then, the HVAC models are modified throughout the comparison between the energy consumption patterns and the real-time monitoring in-field data. In order to maximize the building energy performance, a genetic algorithm (GA)-based optimization technique is applied to the modified HVAC models. Throughout the proposed building energy simulation, finally, the best optimized HVAC control schedule for the target building can be obtained in the form of “supply air temperature schedule”.

Dynamic Model of Compression Refrigeration System with a High Pressure Receiver

2011 ◽  
Vol 130-134 ◽  
pp. 575-579
Author(s):  
Wen Peng Zhai ◽  
Ai Guo Wu ◽  
Yu Wen You
Keyword(s):  
Optimal Control ◽  
Energy Efficiency ◽  
High Pressure ◽  
Energy Consumption ◽  
Dynamic Model ◽  
Control Design ◽  
Building Energy ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Part Load

Vapor compression chiller, the largest proportion of building energy consumption as the design and running characteristics, work at part load for most of the time. To improve the energy efficiency at part load, this thesis details some efforts to develop a dynamic model of a vapor compressor system suitable for optimal control design purpose. It present the model of high pressure liquid receiver which is important for the mass balance of the whole system and make sure it operated in a set-point designed. Additional experiments were also performed to verify the precision of the model.

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