The Analysis of Modifications in Cooling Systems for High-Performance Data Centers. A Case Study

2017 ◽  
Author(s):  
Artur Rusowicz ◽  
Adam Ruciński ◽  
Rafał Laskowski
Keyword(s):  
Air Conditioning ◽  
High Performance ◽  
Energy Savings ◽  
Cooling System ◽  
Capital Expenditure ◽  
Cooling Power ◽  
Power Demand ◽  
Excessive Heat ◽  
Refrigeration Equipment ◽  
Payback Time

One of main issues concerning server room operation is appropriate cooling of electronic modules to prevent excessive heat generation resulting in their damage. Since high cooling powers are required, precision air conditioning systems are used that are specially designed for cooling server and equipment rooms, server cabinets, etc. These devices require very large energy supplies. The paper proposes an upgrade of a cooling system for three server rooms in which refrigeration equipment with a cooling power of 1.873 MW is installed. The average actual cooling power demand is 890 kW, and some units work as a standby. Thir-eight direct-evaporation air-conditioning cabinets are installed. The refrigerant is R407C. The devices have been operated for 14 years; therefore, the refrigeration equipment should be replaced with modern units. The paper compares three approaches: replacing the units with similar ones based on newer technology, introducing contained aisle configurations of rack cabinets and units based on newer technology with additional EconoPhase modules. The application of free cooling was not analyzed since mounting additional heat exchangers was impossible (due to the lack of space and limited roof loading capacity). The paper provides capital and operating costs of the solutions. The introduction of up-to-date units and replacing condensers resulted in lowering the electric power demand by 16%. The simple payback time (SPBT) of this solution is 18.8 years. The energy savings achieved through the second solution (contained aisle configurations of rack cabinets) amount to 37.8%, with SPBT equal to 8.38 years. Variant III, consisting in using modern units with additional EconoPhase modules, significantly improves energy savings (48.3%) but it requires large capital expenditure, with simple payback time of 12.1 years.

scholarly journals The Profitability Analysis Of Enhancement Of Parameters Of The Thermal Insulation Of Building Partitions

2014 ◽  
Vol 60 (3) ◽  
pp. 335-347
Author(s):  
A. Życzyńska ◽  
T. Cholewa
Keyword(s):  
Thermal Insulation ◽  
Energy Savings ◽  
Cooling System ◽  
Residential Buildings ◽  
Building Envelope ◽  
Existing Buildings ◽  
Profitability Analysis ◽  
Payback Time ◽  
Technical Solutions ◽  
New Buildings

Abstract The energy saving tendencies, in reference to residential buildings, can be recently seen in Europe and in the world. Therefore, there are a lot of studies being conducted aiming to find technical solutions in order to improve the energy efficiency of existing, modernized, and also new buildings. However, there are obligatory solutions and requirements, which must be implemented during designing stage of the building envelope and its heating/cooling system. They are gathered in the national regulations. The paper describes the process of raising the energy standard of buildings between 1974–2021 in Poland. Therefore, the objective of this study is to show energy savings, which can be generated by modernization of thermal insulation of partitions of existing buildings and by the use of different ways of heat supply. The calculations are made on the selected multi-family buildings located in Poland, with the assumption of a 15 years payback time. It is shown that it is not possible to cover the costs of the modernization works by the projected savings with the compliance to the assumption of 15 years payback time.

High Performance Single-Phase Liquid Coolers for Power Electronics

2005 ◽  
Author(s):  
Brian C. Y. Cheong ◽  
Peter T. Ireland ◽  
Annegret W. Siebert
Keyword(s):  
Power Electronics ◽  
Gas Turbines ◽  
High Performance ◽  
Cooling System ◽  
Cooling Power ◽  
Reduced Pressure ◽  
Pressure Drops ◽  
Pin Fin ◽  
Aircraft Fuel ◽  
Convective Thermal

This paper presents three generically similar impingement liquid coolers that have been engineered for cooling power electronics on future aero gas turbines. The thermal and hydraulic performances of the coolers have been compared with that of a commercial, state-of-the-art pin fin liquid cooler. It is demonstrated that the impingement liquid coolers outperform thermally the baseline pin fin cooler, and with significantly lower pressure drops. The impingement liquid coolers could also be easily modified to trade reduced pressure drop against higher flowrate or reduced thermal performance. A scaling model has also been developed to predict the thermal performances of the coolers for other types of coolants and flow conditions. The model has been applied for predicting the convective thermal performances of the coolers assuming hot aircraft fuel as the coolant. Future work would include an investigation of alternative convective applications in which the cooling system could be systematically explored.

Dynamic Simulation of an Ejector-Based Cooling System for Residential Solar Air-Conditioning

2012 ◽  
Author(s):  
Stefano Gavioli ◽  
Jean-Marie Seynhaeve ◽  
Yann Bartosiewicz
Keyword(s):  
Dynamic Simulation ◽  
Air Conditioning ◽  
Cooling System ◽  
Geographic Location ◽  
Hot Water ◽  
Cooling Power ◽  
Dynamic Simulation Model ◽  
Hot Season ◽  
Transient Thermal ◽  
Ejector Cycle

A smart and sustainable way to produce cooling power during the hot season is through thermal activated compression. One of the most promising technology is the ejector cycle. An experimental machine based on this technology has been designed and built at Université Catholique de Louvain (UCL). This study presents a dynamic simulation model of a full house incorporating solar collectors to produce domestic hot water and to feed an ejector-based solar air-conditioning machine. The model takes into account geographic location, transient thermal house behaviour, and also integrates a performance map of the ejector cycle based on real measurement campaign. Different types of collectors and storage sizes have been studied as well. In this paper, the developed model is used to analyze and optimize operation and strategy of hot water production and air conditioning. Results show that the full solar solution may cover low energy house needs.

scholarly journals High-performance subambient radiative cooling enabled by optically selective and thermally insulating polyethylene aerogel

2019 ◽  
Vol 5 (10) ◽  
pp. eaat9480 ◽  
Author(s):  
A. Leroy ◽  
B. Bhatia ◽  
C. C. Kelsall ◽  
A. Castillejo-Cuberos ◽  
M. Di Capua H. ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Air Conditioning ◽  
High Performance ◽  
Recent Progress ◽  
Passive Cooling ◽  
Cooling Power ◽  
Radiative Cooling ◽  
Direct Sunlight ◽  
Solar Absorption ◽  
Solar Noon

Recent progress in passive radiative cooling technologies has substantially improved cooling performance under direct sunlight. Yet, experimental demonstrations of daytime radiative cooling still severely underperform in comparison with the theoretical potential due to considerable solar absorption and poor thermal insulation at the emitter. In this work, we developed polyethylene aerogel (PEA)—a solar-reflecting (92.2% solar weighted reflectance at 6 mm thick), infrared-transparent (79.9% transmittance between 8 and 13 μm at 6 mm thick), and low-thermal-conductivity (kPEA = 28 mW/mK) material that can be integrated with existing emitters to address these challenges. Using an experimental setup that includes the custom-fabricated PEA, we demonstrate a daytime ambient temperature cooling power of 96 W/m2 and passive cooling up to 13°C below ambient temperature around solar noon. This work could greatly improve the performance of existing passive radiative coolers for air conditioning and portable refrigeration applications.

Energy and Exergy Analysis of a Hybrid Solar System in Terms of Thermal Energy Production and Cooling

2017 ◽  
Author(s):  
I. P. Koronaki ◽  
M. T. Nitsas ◽  
E. G. Papoutsis
Keyword(s):  
Solar System ◽  
Thermal Energy ◽  
Energy Savings ◽  
Cooling System ◽  
Operating Cost ◽  
Cooling Capacity ◽  
Exergy Efficiency ◽  
Cooling Power ◽  
Adsorption Chiller ◽  
Energy And Exergy

In this study a hybrid solar system, already available in the Laboratory of Applied Thermodynamics at NTUA is examined in terms of thermal energy and cooling power production. The system is installed in Athens, Greece and it comprises of two types of solar collectors, namely one series of CPC-PVT (Compound Parabolic Concentrator-Photovoltaic Thermal) collectors and one series of ETC (Evacuated Tube Collector), one indirect water buffer with an intermediate heat exchanger and a commercial zeolite adsorption chiller (LTC vario, Invensor). Simulations are carried out in order to estimate the energy and exergy efficiency of the system, the produced cooling capacity as well as the thermal energy stored in the buffer. Moreover, the performance of the chiller is evaluated for various months by determining the Cooling Capacity and COP, both solar and thermal. In order to determine, if the proposed solar cooling system performs better than a conventional that covers the same load, the primary energy savings and the reduction of CO2 emissions are calculated. The operating cost savings are also estimated. The simulation results show that the under study systems can indeed work sufficiently when the specific types and surface of collectors are considered. In specific, the system exhibits an average COP of 0.5 for the under study period while its solar exergy efficiency (nearly 2.5%) leads to the conclusion that the system, especially the collectors, can undergo an optimization process.

scholarly journals A Review on Industrial Cooling System

2020 ◽  
Vol 6 (7) ◽  
pp. 1-4
Author(s):  
Shubham Shukla ◽  
Rajeev Arya ◽  
Nilesh Diwakar
Keyword(s):  
Air Conditioning ◽  
Energy Savings ◽  
Cooling System ◽  
Thermal Sensation ◽  
System Modeling ◽  
Thermal Processes ◽  
Hvac System ◽  
Air Conditioning System ◽  
Air Handling Unit ◽  
Hvac System Modeling

The modeling of the heating, ventilation, and air conditioning (HVAC) system is a prominent topic because of its relationship with energy savings and environmental, economic, and technological issues. The modeling of the HVAC system is concerned with the indoor thermal sensation, which is related to the modeling of building, air handling unit (AHU) equipment’s, and indoor thermal processes.  This paper shows the HVAC model and the Winter Air Conditioning System, Summer Air Conditioning System. Until now, many HVAC system modeling approaches are made available, and the techniques have become quite mature.

scholarly journals Desiccant cooling as an alternative to traditional air conditioners in green cooling technology

2019 ◽  
pp. 01-13
Author(s):  
Jani DB
Keyword(s):  
Air Conditioning ◽  
Energy Savings ◽  
Cooling System ◽  
Green Building ◽  
Climatic Conditions ◽  
Coefficient Of Performance ◽  
Low Grade ◽  
Vapor Compression ◽  
Cooling Technology ◽  
Air Conditioning Systems

Desiccant-based dehumidification and air conditioning systems are considered as an energy efficient alternative to traditional vapor compression based air-conditioning systems for green building cooling technology especially in tropical hot and humid ambient climates. It is a novel green cooling technology that makes use of low-grade heat for building air conditioning. It is seen that the desiccant based dehumidification and cooling can efficiently provide comfort conditions in subtropical and especially hot and humid tropical climates. The desiccant integrated novel cooling system has a significant higher coefficient of performance compared to the conventional vapor compression system resulting to substantial electrical energy savings during the summer season by use of renewable solar energy, which also resulted in to major reduction in CO2 emissions. Therefore, these results demonstrate that there is a good potential in desiccant-based dehumidification and cooling system for energy and carbon savings while carry out building air-conditioning. Through a literature review, the feasibility of the desiccant assisted air conditioning in hot and humid climatic conditions is proven and the advantages it can offer in terms energy and cost savings are underscored. Keywords: Air-conditioning; Desiccant cooling; Dehumidification; Green cooling; Thermal comfort

Energy Saving Assessment of Triple-Hybrid Vapor Absorption Building Cooling System Under Hot-Dry Climate

2021 ◽  
Author(s):  
Gaurav Singh ◽  
Ranjan Das
Keyword(s):  
Heat Input ◽  
Air Conditioning ◽  
Energy Savings ◽  
Cooling System ◽  
Electrical Energy ◽  
Coefficient Of Performance ◽  
Absorption System ◽  
Vapor Absorption ◽  
Thermally Driven ◽  
Building Cooling

Abstract Thermally driven vapor absorption-based air-conditioning systems possess many advantages over the compression based systems. However, intermittent availability of input resources affects the operation of these absorption systems which causes discontinuous working. This study aims at examining the electrical and thermodynamic performance of a triple-hybrid vapor absorption-assisted air-conditioning system against a conventional system with the aid of EnergyPlus simulations for a small office building. The outside weather is subjected to hot-dry climatic condition. The heat input source includes biomass and solar energy-based resources. Auxiliary heat input is also used to ensure smooth operation. The performance of the absorption system is assessed at different generator temperature (70 °C–80 °C) and solar collector area (400 m2–500 m2). The results show that, by using absorption-based systems, a maximum of 34.1% electrical energy savings can be ensured at 500 m2 collector area with 70 °C generator temperature. The coefficient of performance of the absorption system escalates from 0.50 to 0.52 by increasing the generator temperature form 70 °C to 80 °C. Under the condition of 70 °C generator temperature and 500 m2 collector area, the absorption system can be made fully renewable energy dependent.

ANALYSIS OF COMPETING VARIANTS OF AIR CONDITIONING SYSTEMS WITHOUT AIR EXTRACTION FROM ENGINES AT THE STAGE OF PASSENGER AIRCRAFT ONBOARD SYSTEMS CONCEPTUAL DESIGN

2019 ◽  
Vol 6 (3) ◽  
pp. 80-85
Author(s):  
Denis Igorevich Smagin ◽  
Konstantin Igorevich Starostin ◽  
Roman Sergeevich Savelyev ◽  
Anatoly Anatolyevich Satin ◽  
Anastasiya Romanovna Neveshkina ◽  
...  
Keyword(s):  
Conceptual Design ◽  
Air Conditioning ◽  
Research University ◽  
Cooling System ◽  
Fuel Efficiency ◽  
Air Cooling ◽  
Moscow Aviation Institute ◽  
Air Conditioning System ◽  
Low Efficiency ◽  
Air Conditioning Systems

One of the ways to achieve safety and comfort is to improve on-board air conditioning systems.The use of air cooling machine determines the air pressure high level at the point of selection from the aircraft engine compressor. Because of the aircraft operation in different modes and especially in the modes of small gas engines, deliberately high stages of selection have to be used for ensuring proper operation of the refrigeration machine in the modes of the aircraft small gas engines. Into force of this, most modes of aircraft operation have to throttle the pressure of the selected stage of selection, which, together with the low efficiency of the air cycle cooling system, makes the currently used air conditioning systems energy inefficient.A key feature of the architecture without air extraction from the main engines compressors is the use of electric drive compressors as a source of compressed air.A comparative analysis of competing variants of on-board air conditioning system without air extraction from engines for longrange aircraft projects was performed at the Moscow Aviation Institute (National Research University).The article deals with the main approaches to the decision-making process on the appearance of a promising aircraft on-board air conditioning system at the stage of its conceptual design and formulated the basic requirements for the structure of a complex criterion at different life cycle stages.The level of technical and technological risk, together with a larger installation weight, will require significant costs for development, testing, debugging and subsequent implementation, but at the same time on-board air conditioning system scheme without air extraction from the engines will achieve a significant increase in fuel efficiency at the level of the entire aircraft.

scholarly journals Numerical Evaluation of a HVAC System Based on a High-Performance Heat Transfer Fluid

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3298
Author(s):  
Gianpiero Colangelo ◽  
Brenda Raho ◽  
Marco Milanese ◽  
Arturo de Risi
Keyword(s):  
Heat Transfer ◽  
High Performance ◽  
Cooling System ◽  
Electrical Energy ◽  
Simulation Software ◽  
Heat Transfer Fluid ◽  
Hvac System ◽  
Dynamic Simulations ◽  
Heating And Cooling ◽  
The University

Nanofluids have great potential to improve the heat transfer properties of liquids, as demonstrated by recent studies. This paper presents a novel idea of utilizing nanofluid. It analyzes the performance of a HVAC (Heating Ventilation Air Conditioning) system using a high-performance heat transfer fluid (water-glycol nanofluid with nanoparticles of Al2O3), in the university campus of Lecce, Italy. The work describes the dynamic model of the building and its heating and cooling system, realized through the simulation software TRNSYS 17. The use of heat transfer fluid inseminated by nanoparticles in a real HVAC system is an innovative application that is difficult to find in the scientific literature so far. This work focuses on comparing the efficiency of the system working with a traditional water-glycol mixture with the same system that uses Al2O3-nanofluid. The results obtained by means of the dynamic simulations have confirmed what theoretically assumed, indicating the working conditions of the HVAC system that lead to lower operating costs and higher COP and EER, guaranteeing the optimal conditions of thermo-hygrometric comfort inside the building. Finally, the results showed that the use of a nanofluid based on water-glycol mixture and alumina increases the efficiency about 10% and at the same time reduces the electrical energy consumption of the HVAC system.

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