Refrigeration Heat Exchanger Systems for Server Rack Cooling in Data Centers

2009 ◽  
Author(s):  
Takeshi Tsukamoto ◽  
Jyunji Takayoshi ◽  
Roger R. Schmidt ◽  
Madhusudan K. Iyengar
Keyword(s):  
Heat Exchanger ◽  
Data Center ◽  
Heat Exchangers ◽  
Energy Savings ◽  
Vapor Compression ◽  
Data Center Cooling ◽  
Thermal Data ◽  
Coolant Loop ◽  
Vapor Compression System

In 2005, IBM released a water cooled heat exchanger product that significantly enhanced data center cooling capability while also demonstrating substantial energy savings. In 2008, IBM released an enhanced water less solution to cool the electronic racks via a R410A refrigerant based vapor compression system, which is the focus of this paper. The paper provides a detailed description of device and coolant loop construction, the experimental thermal data collected, as well as a discussion of its’ cooling energy efficiency relative to both typical air cooled facilities and water cooled heat exchangers, respectively. A data center level case study was performed with experimental measurements collected and discussed herein. Significant energy savings were realized even when the heat exchanger devices were implemented on a small part of the data center. Based on the test data and the experimental data center study, the CRAC units based loops have a COP of 1.95, while the refrigerant refrigerant heat exchanger loop has a COP of 5.0.

Thermodynamic Analysis of Hybrid Liquid-Air-Based Data Center Cooling Strategies

2014 ◽  
Author(s):  
A. Bhalerao ◽  
A. Ortega ◽  
A. P. Wemhoff
Keyword(s):  
Thermal Management ◽  
Thermodynamic Analysis ◽  
Data Center ◽  
Heat Exchangers ◽  
Energy Savings ◽  
Cost Savings ◽  
Exergy Destruction ◽  
Cooling Systems ◽  
Rear Door ◽  
Data Center Cooling

Energy savings in data center cooling systems equate to cost savings for the data center operator. Recently, investigators have considered alternative hybrid liquid-air technologies for data center thermal management such as in-row coolers, rear door heat exchangers, and overhead coolers. This study employs the in-house data center modeling tool Villanova Thermodynamic Analysis of Systems (VTAS) software package to ascertain the influence of hybrid liquid-air components on overall data center exergy destruction. The results show that the exergy destruction decreases for a hybrid liquid-air system using only an in-row cooler. As the in-row cooler removes a greater fraction of heat from the hot aisle, the total exergy destruction in the data center increases by a small amount. This analysis is extended for various configurations containing an in-row cooler, an overhead cooler, a rear door heat exchanger, and a CRAH unit to show that using hybrid liquid-air technologies without a CRAH unit is the most thermodynamically favorable.

scholarly journals An Extended Grid Diagram for Heat Exchanger Network Retrofit Considering Heat Exchanger Types

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2656 ◽  
Author(s):  
Bohong Wang ◽  
Jiří Jaromír Klemeš ◽  
Petar Sabev Varbanov ◽  
Min Zeng
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Energy Savings ◽  
Heat Exchanger Network ◽  
Type Selection ◽  
Temperature Ranges ◽  
Double Pipe ◽  
Utility Cost ◽  
Retrofit Design

Heat exchanger network (HEN) retrofit is a vital task in the process design to improve energy savings. Various types of heat exchangers such as shell and tube, double-pipe, compact plate, and spiral tube have their working temperature ranges and costs. Selecting suitable types of heat exchangers according to their temperature ranges and costs is a crucial aspect of industrial implementation. However, considering the type of heat exchangers in the HEN retrofit process is rarely seen in previous publications. This issue can be solved by the proposed Shifted Retrofit Thermodynamic Grid Diagram with the Shifted Temperature Range of Heat Exchangers (SRTGD-STR). The temperature ranges of six widely used heat exchanger types are coupled in the grid diagram. This diagram enables the visualisation of identifying the potential retrofit plan of HEN with heat-exchanger type selection. The retrofit design aims to minimise utility cost and capital cost. An illustrative example and a case study are presented to show the effectiveness of the method.

A Practical Approach to Energy Optimization Using Pinch Analysis: A Case Study of an Oil Refinery

2021 ◽  
Author(s):  
Paschal Uzoma Ndunagu ◽  
Emeka Emmanuel Alaike ◽  
Theophile Megueptchie
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Energy Savings ◽  
Operating Cost ◽  
Energy Optimization ◽  
Distillation Unit ◽  
Pinch Analysis ◽  
Cost Index ◽  
Heat Exchanger Network ◽  
Total Cost

Abstract The objective of this paper is to perform an energy optimization study using pinch analysis on the Heat Exchanger Network (HEN) of a Crude Distillation Unit to maximum heat recovery, minimize energy consumption and increase refining margin. The heat exchanger network (HEN) considered comprises exchangers from the pre-heat section of the atmospheric distillation unit, which recovers heat from the product streams to incrementally heat the crude oil feed stream before entering the furnace. This paper illustrates how to perform a detailed HEN retrofitting study using an established design method known as Pinch Analysis to reduce the operating cost by increasing energy savings of the HEN of an existing complex refinery of moderate capacity. Analysis and optimization were carried out on the HEN of the CDU consist a total of 19 heat exchangers which include: process to process (P2P) heat exchangers, heaters and coolers. In the analysis, different feasible retrofit scenarios were generated using the pinch analysis approach. The retrofit designs included the addition of new heat exchangers, rearrangement of heat exchanger (re-sequencing) and re-piping of existing exchangers. Aspen Hysys V9 was used to simulate the CDU and Aspen Energy Analyser was used to perform pinch analysis on the HEN of the pre-heat train. Several retrofit scenarios were generated, the optimum retrofit solution was a trade-off between the capital cost of increasing heat exchanger surface area, payback time, energy / operating cost savings of hot and cold utilities. Results indicated that by rearrangement (Re-sequencing), the pre-heat train can reduce hot (fired heat) and cold (air and cooling water) utilities consumption to improve energy savings by 8% which includes savings on fired heat of about 4.6 MW for a payback period of 2 years on capital investment. The results generated were based on a ΔTmin of 10°C and pinch temperature of 46.3°C. Initial sensitivity analysis on the ΔTmin indicated that variation of total cost index is quite sensitive and increases with increase in ΔTmin at the temperature range of 14.5-30°C, however total cost index remains constant and minimal at a temperature range between 10°C-14.5°C for the CDU preheat train under study. In addition, the implementation of the optimum retrofit result is straightforward and feasible with minimum changes to the existing base case/design.

Modeling Large-Size Boilers As a Set of Heat Exchangers: Tips and Tricks

2001 ◽  
Author(s):  
Cristóbal Cortés ◽  
Luis I. Díez ◽  
Antonio Campo
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Heat Recovery ◽  
Practical Calculation ◽  
Approximate Methods ◽  
Monitoring Method ◽  
Large Size ◽  
Thermoelectric Plant ◽  
The One

Abstract Practical calculation of the heat-recovery sections of large-size boilers is still based on approximate methods. On the one hand, CFD-based models cannot directly handle the geometric intricacy of tube bundles, and thus rely on volume-averaged source terms that demand empirical input. On the other hand, the standard, lumped heat exchanger calculation, which can be a far simpler and more robust alternative, fails in several important aspects, mainly related to the effects of thermal radiation and the coupling between several sections. In this paper, we consider the diverse sections of a coal-fired utility boiler as a case study to show how to deal with these shortcomings. Under the objective of developing a simple monitoring method, we extend the traditional heat exchanger model to take into account most of the peculiarities of boiler superheaters, reheaters and economizers. Techniques range from the re-examination of analytical solutions to the auxiliary use of CFD calculations. The models are assembled to simulate the thermal performance of the boiler as a whole unit. Results are validated against actual measurements taken at a thermoelectric plant.

Comparative Analysis of Vapor Compression and Hybrid Liquid Desiccant Dehumidification Systems

2005 ◽  
Author(s):  
A. M. Al-Jaafari ◽  
S. A. Sherif
Keyword(s):  
Energy Savings ◽  
Cooling System ◽  
The United States ◽  
Normal Operation ◽  
Weather Data ◽  
Energy Calculation ◽  
Vapor Compression ◽  
Liquid Desiccant ◽  
Study Results ◽  
Vapor Compression System

The objective of this study was to evaluate the energy savings of a commercially available hybrid liquid desiccant (HLD) cooling system relative to a conventional vapor compression system used for an existing school building where 100% outside air is used for ventilation. Psychrometric analysis and hour-by-hour simulations for three energy models were developed for three cities in the United States using available weather data assuming normal operation and typical building occupancy. Energy calculation software such as the Carrier Hourly Analysis Program (HAP 4.1) and Desicalc along with generated spreadsheets was used to compute the energy consumption for the models under study. Results of each model are summarized and comparisons are made. The annual energy savings employing the HLD system were found to reach 46% for Chicago, 37% for Gainesville and 32% for Miami. Simple cost analysis and associated payback periods were also performed.

scholarly journals Energy and economy savings in the process of methanol synthesis unsig Pinch technology

2004 ◽  
Vol 69 (10) ◽  
pp. 827-837 ◽  
Author(s):  
Mirjana Kijevcanin ◽  
Bojan Djordjevic ◽  
Ozren Ocic ◽  
Mladen Crnomarkovic ◽  
Maja Maric ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Methanol Synthesis ◽  
Heat Exchangers ◽  
Energy Savings ◽  
Energy Costs ◽  
Pinch Analysis ◽  
Trade Off ◽  
Total Cost ◽  
Capital Costs ◽  
Pinch Technology

A heat exchanger network (HEN) for the process of methanol synthesis has been studied by pinch design analysis. Great economic and energy savings were realized by the pinch analysis in comparison to the existing plant. Also, it was found that it is possible to reduce the requirements for the consumption of utilities. The HEN was reconstruded by adding new heat exchangers. In order to produce new HEN, the capital costs had to be increased, but the total cost trade-off between the capital and energy costs will be decrease by 30 %.

Comparison of Deep Reinforcement Learning Algorithms in Data Center Cooling Management: A Case Study

2021 ◽  
Author(s):  
Tianyang Hua ◽  
Jianxiong Wan ◽  
Shan Jaffry ◽  
Zeeshan Rasheed ◽  
Leixiao Li ◽  
...  
Keyword(s):  
Reinforcement Learning ◽  
Data Center ◽  
Learning Algorithms ◽  
Data Center Cooling

Analytical Modeling of Energy Consumption and Thermal Performance of Data Center Cooling Systems: From the Chip to the Environment

2007 ◽  
Author(s):  
Madhusudan Iyengar ◽  
Roger R. Schmidt
Keyword(s):  
Energy Consumption ◽  
Data Center ◽  
Energy Use ◽  
It Industry ◽  
Cooling Systems ◽  
Air Temperatures ◽  
Data Center Cooling ◽  
Total Data ◽  
Heat Transfer Phenomenon

The increasingly ubiquitous nature of computer and internet usage in our society, has driven advances in semiconductor technology, server packaging, and cluster level optimizations, in the IT industry. Not surprisingly this has an impact on our societal infrastructure with respect to providing the requisite energy to fuel these power hungry machines. Cooling has been found to contribute to about a third of the total data center energy consumption, and is the focus of this study. In this paper we develop and present physics based models to allow the prediction of the energy consumption and heat transfer phenomenon in a data center. These models allow the estimation of the microprocessor junction and server inlet air temperatures for different flow and temperature conditions at various parts of the data center cooling infrastructure. For a case study example considered, the chiller energy use was the biggest fraction of about 41% and also the most inefficient. The room air conditioning was the second largest energy component and also the second most inefficient. A sensitivity analysis of plant and chiller energy efficiency with chiller set point temperature and outdoor air conditions is also presented.

Parametric Study of Heat Insulation in Case of Plate Heat Exchangers

2015 ◽  
Vol 775 ◽  
pp. 50-53
Author(s):  
Milan Kubín ◽  
Jiří Hirš
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Heat Insulation ◽  
Plate Heat Exchanger ◽  
Heat Losses ◽  
Heat Energy ◽  
Plate Heat ◽  
Surrounding Environment ◽  
Parametric Case

Contribution is aimed on lost heat of plate heat exchangers to surrounding environment. Heat losses to vicinity are insignificant relative to transferred heat flow in the plate heat exchangers. This small part of the lost heat is demonstrated in parametric case study of plate heat exchanger, where is the lost part of heat energy lower than 0.50 % in ordinary cases.

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