This paper introduces the subject of industrial cooling and discusses the most important energy savings that are possible in this area.
Cooling is very expensive, so it is important that it is used only where necessary, and that only the most efficient technology is used. For thermodynamic reasons, the energy efficiency of a cooling system increases with decreasing temperature differential. It is therefore crucial to keep this differential as low as possible.
Three main types of cooling systems prevail in industrial environments: dry cooling, evaporative cooling, and compression cooling. This paper explains their main working principles and characteristics. Other types, such as absorption cooling, gas expansion, and thermo-electric cooling, are not treated in this application guide because of their limited presence in industry.
Each system has its own application domain. The choice of the right cooling system is one of the important initial decisions that must be taken in order to achieve maximum energy efficiency. Furthermore, this paper discusses several specific energy saving actions for each of the three cooling systems.
Significant energy savings can be made by installing variable frequency drives on fans (dry cooling, evaporative cooling), pumps (evaporative cooling, compression cooling), and compressors (compression cooling).
The starting point for a review of an industrial cooling system should be to see what options there might be for minimizing the heat load, and then to see if there are any alternative uses for the waste heat produced. Once the demand has been reduced, attention can then be given to optimizing the cooling system to run efficiently.
Evaporative cooling systems are the most popular type found in industry. This Application Note explains how they work and the energy and water saving opportunities that they may present. For both evaporative and dry air cooling systems, variations in ambient air conditions and process loads, means that they will spend much of their time working at part load operation. On/off and variable speed control of the system fans and pumps can give large energy savings, but the selection of methods depends on the detailed design of the cooling plant. Care also must be taken to also ensure that the system will work satisfactorily at partial load.
Water treatment and selection, and maintenance of cooling tower fill are important for effective and reliable operation, and have direct impact on energy use. Regular monitoring of the system will ensure that any changes in performance can be identified and remedial measures taken.
This application note makes suggestions of well proven techniques to save energy, that vary from simple maintenance tasks to operational and equipment changes that will require the input of a specialist.
Industrial energy auditing and reportingVignesh Sekar
Industrial Energy Audit is defined as the verification, monitoring and analysis of energy use including submission of technical report containing all the recommendations for improving energy efficiency with cost analysis and an action plan to reduce consumption
The starting point for a review of an industrial cooling system should be to see what options there might be for minimizing the heat load, and then to see if there are any alternative uses for the waste heat produced. Once the demand has been reduced, attention can then be given to optimizing the cooling system to run efficiently.
Evaporative cooling systems are the most popular type found in industry. This Application Note explains how they work and the energy and water saving opportunities that they may present. For both evaporative and dry air cooling systems, variations in ambient air conditions and process loads, means that they will spend much of their time working at part load operation. On/off and variable speed control of the system fans and pumps can give large energy savings, but the selection of methods depends on the detailed design of the cooling plant. Care also must be taken to also ensure that the system will work satisfactorily at partial load.
Water treatment and selection, and maintenance of cooling tower fill are important for effective and reliable operation, and have direct impact on energy use. Regular monitoring of the system will ensure that any changes in performance can be identified and remedial measures taken.
This application note makes suggestions of well proven techniques to save energy, that vary from simple maintenance tasks to operational and equipment changes that will require the input of a specialist.
Industrial energy auditing and reportingVignesh Sekar
Industrial Energy Audit is defined as the verification, monitoring and analysis of energy use including submission of technical report containing all the recommendations for improving energy efficiency with cost analysis and an action plan to reduce consumption
Thermal Power Plant Boiler Efficiency ImprovementAnkur Gaikwad
Boiler is one of the central equipment used in power generation & chemical process industries. Consequently, improving boiler efficiency is instrumental in bringing down costs substantially with a few simple measures. Some of these measures are discussed in this presentation
PRESSURIZED FLUIDIZED BED COMBUSTION BOILERKRUNAL RAVAL
In PFBC, the combustor and hot gas cyclones are all enclosed in a pressure vessel. Both coal and sorbent have to be fed across the pressure boundary, and
similar provision for ash removal is necessary. For hard coal applications, the coal and limestone can be crushed together, and then fed as a paste, with 25% water. As with atmospheric FBC (CFBC or BFBC), the combustion temperature between 800-900°C has the advantage that NOx formation is less. SO2
emissions can be reduced by the injection of a sorbent, and its subsequent removal with the ash.
Industrial heat pumps, using waste process heat as the source, deliver heat at a higher temperature for use in industrial process heating, preheating, or space heating. There is debate over their definition, but, in general, they represent a worthwhile method of improving the energy efficiency of industrial processes and reducing primary energy consumption.
Industrial heat pumps (IHPs) offer various opportunities in all types of manufacturing processes and operations. Increased energy efficiency is certainly their most obvious benefit, but few companies have realized the untapped potential of IHPs in solving production and environmental problems. This Application Note demonstrates that IHPs can offer the least-cost option for removing bottlenecks in production processes and allowing greater product throughput and, in fact, may be an industrial facility’s best way of significantly and cost-effectively reducing combustion-related emissions.
Thermal Power Plant Boiler Efficiency ImprovementAnkur Gaikwad
Boiler is one of the central equipment used in power generation & chemical process industries. Consequently, improving boiler efficiency is instrumental in bringing down costs substantially with a few simple measures. Some of these measures are discussed in this presentation
PRESSURIZED FLUIDIZED BED COMBUSTION BOILERKRUNAL RAVAL
In PFBC, the combustor and hot gas cyclones are all enclosed in a pressure vessel. Both coal and sorbent have to be fed across the pressure boundary, and
similar provision for ash removal is necessary. For hard coal applications, the coal and limestone can be crushed together, and then fed as a paste, with 25% water. As with atmospheric FBC (CFBC or BFBC), the combustion temperature between 800-900°C has the advantage that NOx formation is less. SO2
emissions can be reduced by the injection of a sorbent, and its subsequent removal with the ash.
Industrial heat pumps, using waste process heat as the source, deliver heat at a higher temperature for use in industrial process heating, preheating, or space heating. There is debate over their definition, but, in general, they represent a worthwhile method of improving the energy efficiency of industrial processes and reducing primary energy consumption.
Industrial heat pumps (IHPs) offer various opportunities in all types of manufacturing processes and operations. Increased energy efficiency is certainly their most obvious benefit, but few companies have realized the untapped potential of IHPs in solving production and environmental problems. This Application Note demonstrates that IHPs can offer the least-cost option for removing bottlenecks in production processes and allowing greater product throughput and, in fact, may be an industrial facility’s best way of significantly and cost-effectively reducing combustion-related emissions.
Industrial heat pumps, using waste process heat as the source, deliver heat at a higher temperature for use in industrial process heating, preheating, or space heating. There is debate over their definition, but, in general, they represent a worthwhile method of improving the energy efficiency of industrial processes and reducing primary energy consumption.
Industrial heat pumps (IHPs) offer various opportunities in all types of manufacturing processes and operations. Increased energy efficiency is certainly their most obvious benefit, but few companies have realised the untapped potential of IHPs in solving production and environmental problems. This Application Note demonstrates that IHPs can offer the least-cost option for removing bottlenecks in production processes and allowing greater product throughput and, in fact, may be an industrial facility’s best way of significantly and cost-effectively reducing combustion-related emissions.
The energy costs related to compressed air represent between 10 to 15% of the electricity bill of the average industrial consumer. This application guide gives an overview of technical and organizational solutions that will maximize the energetic efficiency of the system. Implementation of these measures can save up to 25% of the systems’ energy consumption.
A first important question to ask is whether compressed air is the best available technique for the required solutions. In many cases other, more energy efficient technologies are available.
If compressed air is the best available technique, several actions can improve the energy efficiency of the system:
• Any design of a new system or the assessment of an existing system should start with an analysis of the needs. If the air demand is variable, an energy efficient control system for dealing with those load variations should be chosen.
• The compressed air distribution network should be carefully designed and maintained. In particular, reducing air leaks can have a significant positive influence on the energy efficiency of the system.
• For thermodynamic reasons, reducing the inlet air temperature and the outlet air pressure has an important influence on the systems’ energy efficiency.
• If air dryers are required for avoiding equipment degradation, they should be carefully selected, based on their energy efficiency.
• In some cases, the heat losses of a compressed air system can be recovered for heating applications.
Finally, maximizing the energy efficiency of a compressed air system is not a one-time action. Continuous monitoring of key parts, and adjusting them when necessary, is indispensable.
The supply of compressed air accounts for between 10 to 15% of the electricity bill of the average industrial consumer. Fortunately, compressed air systems frequently offer some easy to identify and rectify energy saving opportunities. These should be a priority at all sites using this versatile but costly resource.
The flexibility of compressed air means that it can be used for an ever growing number of applications on a site, with insufficient thought given to the impact on the overall system, or its true cost. Even when poorly maintained, a compressed air system may appear to function satisfactorily, and so problems will not become apparent without systematic maintenance procedures being in place.
This application guide gives an overview of technical and organizational solutions that will maximize the energetic efficiency of the system. Implementation of these measures can save up to 25% of the systems’ energy consumption.
Experimental Analysis of Refrigeration system using Microchannel condenser & ...AM Publications
Micro channel condenser now days can be effectively used due to its compact size in automobile sector. For
its performance, refrigeration set up designed to detect experimental performance of microchannel condenser. In this
paper performance analysis of microchannel condenser compared with round tube and coil tube. In analysis of
microchannel condensers it can be found more effective at various loads and operating conditions. For review same size of
microchannel and round tube condenser are considered. From the previous experiments the micro-channel condenser was
made to have nearly an identical face area, depth and fin density as the round-tube condenser which was the baseline. Also
varying the refrigerants, C.O.P & Efficiency of micro channel the various reviews of reviewer micro channel condenser
can be efficient and also refrigerator system requires less power.
Performance evaluation of an incorporation of a compact liquid desiccant syst...eSAT Journals
Abstract The primary goal of this paper is to suggest incorporation of a compact liquid desiccant system into an evaporative cooling-assisted 100% outdoor air system as an alternative proposal to the traditional vapor compression refrigeration system, especially with small loads, as well as to counteract the variation of climates. Current study presents an experimental analysis for building air conditioning system with using a LiCl aqueous solution as a liquid desiccant. Four air flow rate values are used for obtaining variable values of cooling capacity. Thermal and electrical COP is adopted to evaluate the system performance. The proposed system has the ability to improve indoor air quality, energy saving and environmental protection. Keywords: Air conditioning; Liquid desiccant; Evaporative cooling; 100% Outdoor air; Energy saving
Design Calculation of Lab Based Vapour Compression Systemijtsrd
This paper deals with experimental investigation to calculate the value of main components of vapor compression refrigeration system and experimental results by using three different length of the capillary tube. At present, there are many types of refrigeration systems but the most widely used is vapor compression refrigeration system. This system is mainly used in air conditioning in buildings, electronic materials, automobile air conditioners, freezers, household refrigerators and even in supermarkets. This lab based refrigeration system is used R 134a because it can be replaced successfully for R 12 refrigerant and useful for many applications now. Moreover, it can be handling safely and has no damage effect to ozone layer. Ko Ko | Khin Maung Than | Aye Aye San "Design Calculation of Lab Based Vapour Compression System" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-6 , October 2019, URL: https://www.ijtsrd.com/papers/ijtsrd29213.pdf Paper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/29213/design-calculation-of-lab-based-vapour-compression-system/ko-ko
Design Calculation of Main Components for Lab Based Refrigeration Systemijtsrd
The purpose of this paper is for the students to know the basic function of main components of refrigeration system. Theoretical and experimental of design calculation of main components and their results are reported in this paper. During the performance of testing, the length of expansion device is varied and the result data are also described. In this system, R134a refrigerant is used as working substance. Because it is now being used for a replacement of R 12 CFC refrigerant. It can be handled safely because it is not toxic, corrosive and flammable. Moreover, it has no damage effect to ozone layer and greenhouse. Ko Ko | Aye Aye San | Khin Maung Than "Design Calculation of Main Components for Lab Based Refrigeration System" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-6 , October 2019, URL: https://www.ijtsrd.com/papers/ijtsrd29212.pdf Paper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/29212/design-calculation-of-main-components-for-lab-based-refrigeration-system/ko-ko
A new generation of instruments and tools to monitor buildings performanceLeonardo ENERGY
What is the added value of monitoring the flexibility, comfort, and well-being of a building? How can occupants be better informed about the performance of their building? And how to optimize a building's maintenance?
The slides were presented during a webinar and roundtable with a focus on a new generation of instruments and tools to monitor buildings' performance, and their link with the Smart Readiness Indicator (SRI) for buildings as introduced in the EU's Energy Performance of Buildings Directive (EPBD).
Link to the recordings: https://youtu.be/ZCFhmldvRA0
Addressing the Energy Efficiency First Principle in a National Energy and Cli...Leonardo ENERGY
When designing energy and climate policies, EU Member States have to apply the Energy Efficiency First Principle: priority should be given to measures reducing energy consumption before other decarbonization interventions are adopted. This webinar summarizes elements of the energy and climate policy of Cyprus illustrating how national authorities have addressed this principle so far, and outline challenges towards its much more rigorous implementation that is required in the coming years.
Auctions for energy efficiency and the experience of renewablesLeonardo ENERGY
Auctions are an emerging market-based policy instrument to promote energy efficiency that has started to gain traction in the EU and worldwide. This presentation provides an overview and comparison of several energy efficiency auctions and derives conclusions on the effects of design elements based on auction theory and on experiences of renewable energy auctions. We include examples from energy efficiency auctions in Brazil, Canada, Germany, Portugal, Switzerland, Taiwan, UK, and US.
A recording of this presentation can be viewed at:
https://youtu.be/aC0h4cXI9Ug
Energy efficiency first – retrofitting the building stock finalLeonardo ENERGY
Retrofitting the building stock is a challenging undertaking in many respects - including costs. Can it nevertheless qualify as a measure under the Energy Efficiency First principle? Which methods can be applied for the assessment and what are the results in terms of the cost-effectiveness of retrofitting the entire residential building stock? How do the results differ for minimization of energy use, CO2 emissions and costs? And which policy conclusions can be drawn?
This presentation was used during the 18th webinar in the Odyssee-Mure on Energy Efficiency Academy on February 3, 2022.
A link to the recording: https://youtu.be/4pw_9hpA_64
How auction design affects the financing of renewable energy projects Leonardo ENERGY
Recording available at https://youtu.be/lPT1o735kOk
Renewable energy auctions might affect the financing of renewable energy (RE) projects. This webinar presents the results of the AURES II project exploring this topic. It discusses how auction designs ranging from bid bonds to penalties and remuneration schemes impact financing and discusses creating a low-risk auction support framework.
This presentation discusses the contribution of Energy Efficiency Funds to the financing of energy efficiency in Europe. The analysis is based on the MURE database on energy efficiency policies. As an example, the German Energy Efficiency Fund is described in more detail.
This is the 17th webinar in the Odyssee-Mure on Energy Efficiency Academy.
Recordings are available on: https://youtu.be/KIewOQCgQWQ
(see updated version of this presentation:
https://www.slideshare.net/sustenergy/energy-efficiency-funds-in-europe-updated)
The Energy Efficiency First Principle is a key pillar of the European Green Deal. A prerequisite for its widespread application is to secure financing for energy efficiency investments.
This presentation discusses the contribution of Energy Efficiency Funds to the financing of energy efficiency in Europe. The analysis is based on the MURE database on energy efficiency policies. As an example, the German Energy Efficiency Fund is described in more detail.
This is the 17th webinar in the Odyssee-Mure on Energy Efficiency Academy.
Recordings are available on: https://youtu.be/KIewOQCgQWQ
Five actions fit for 55: streamlining energy savings calculationsLeonardo ENERGY
During the first year of the H2020 project streamSAVE, multiple activities were organized to support countries in developing savings estimations under Art.3 and Art.7 of the Energy Efficiency Directive (EED).
A fascinating output of the project so far is the “Guidance on Standardized saving methodologies (energy, CO2 and costs)” for a first round of five so-called Priority Actions. This Guidance will assist EU member states in more accurately calculating savings for a set of new energy efficiency actions.
This webinar presents this Guidance and other project findings to the broader community, including industry and markets.
AGENDA
14:00 Introduction to streamSAVE
(Nele Renders, Project Coordinator)
14:10 Views from the EU Commission and the link with Fit-for-55 (Anne-Katherina Weidenbach, DG ENER)
14:20 The streamSAVE guidance and its platform illustrated (Elisabeth Böck, AEA)
14:55 A view from industry: What is the added value of streamSAVE (standardized) methods in frame of the EED (Conor Molloy, AEMS ECOfleet)
14:55 Country experiences: the added value of standardized methods (Elena Allegrini, ENEA, Italy)
The recordings of the webinar can be found on https://youtu.be/eUht10cUK1o
This webinar analyses energy efficiency trends in the EU for the period 2014-2019 and the impact of COVID-19 in 2020 (based on estimates from Enerdata).
The speakers present the overall trend in total energy supply and in final energy consumption, as well as details by sector, alongside macro-economic data. They will explain the main drivers of the variation in energy consumption since 2014 and determine the impact of energy savings.
Speakers:
Laura Sudries, Senior Energy Efficiency Analyst, Enerdata
Bruno Lapillonne, Scientific Director, Enerdata
The recordings of the presentation (webinar) can be viewed at:
https://youtu.be/8RuK5MroTxk
Energy and mobility poverty: Will the Social Climate Fund be enough to delive...Leonardo ENERGY
Prior to the current soaring energy prices across Europe, the European Commission proposed, as part of the FitFor55 climate and energy package, the EU Social Climate Fund to mitigate the expected social impact of extending the EU ETS to transport and heating.
The report presented in this webinar provides an update of the European Energy Poverty Index, published for the first time in 2019, which shows the combined effect of energy and mobility poverty across Member States. Beyond the regular update of the index, the report provides analysis of the existing EU policy framework related to energy and transport poverty. France is used as a case study given the “yellow vest” movement, which was triggered by the proposed carbon tax on fuels.
Watch the recordings of the webinar:
https://youtu.be/i1Jdd3H05t0
Does the EU Emission Trading Scheme ETS Promote Energy Efficiency?Leonardo ENERGY
This policy brief analyzes the main interacting mechanisms between the Energy Efficiency Directive (EED) and the EU Emission Trading Scheme (ETS). It presents a detailed top-down approach, based on the ODYSSEE energy indicators, to identify energy savings from the EU ETS.
The main task consists in isolating those factors that contribute to the change in energy consumption of industrial branches covered by the EU ETS, and the energy transformation sector (mainly the electricity sector).
Speaker:
Wolfgang Eichhammer (Head of the Competence Center Energy Policy and Energy Markets @Fraunhofer Institute for Systems and Innovation Research ISI)
The recordings of this webinar can be watched via:
https://youtu.be/TS6PxIvtaKY
Energy efficiency, structural change and energy savings in the manufacturing ...Leonardo ENERGY
The first part of the presentations presents the energy efficiency improvements in the manufacturing sector since 2000, and the role of structural change between the different branches and energy savings. It will compare the improvements in Denmark and other countries with EU average. This part is based on ODYSSEE data.
The second part of the presentation presents the development in Denmark in more detail, and it will compare the energy efficiency improvement, corrected for structural change, with the reported savings from the Energy Efficiency Obligation Scheme.
Recordings of the live webinar are on https://youtu.be/VVAdw_CS51A
Energy Sufficiency Indicators and Policies (Lea Gynther, Motiva)Leonardo ENERGY
This policy brief looks at questions ‘how to measure energy sufficiency’, ‘which policies and measures can be used to address energy sufficiency’ and ‘how they are used in Europe today’.
Energy sufficiency refers to a situation where everyone has access to the energy services they need, whilst the impacts of the energy system do not exceed environmental limits. The level of ambition needed to address energy sufficiency is higher than in the case of energy efficiency.
This is the 13th edition of the Odyssee-Mure on Energy Efficiency Academy, and number 519 in the Leonardo ENERGY series. The recording of the live presentation can be found on https://www.youtube.com/watch?v=jEAdYbI0wDI&list=PLUFRNkTrB5O_V155aGXfZ4b3R0fvT7sKz
The Super-efficient Equipment and Appliance Deployment (SEAD) Initiative Prod...Leonardo ENERGY
The Super-efficient Equipment and Appliance Deployment (SEAD) Initiative Product Efficiency Call to Action, by Melanie Slade - IEA and Nicholas Jeffrey - UK BEIS
Transcript: Selling digital books in 2024: Insights from industry leaders - T...BookNet Canada
The publishing industry has been selling digital audiobooks and ebooks for over a decade and has found its groove. What’s changed? What has stayed the same? Where do we go from here? Join a group of leading sales peers from across the industry for a conversation about the lessons learned since the popularization of digital books, best practices, digital book supply chain management, and more.
Link to video recording: https://bnctechforum.ca/sessions/selling-digital-books-in-2024-insights-from-industry-leaders/
Presented by BookNet Canada on May 28, 2024, with support from the Department of Canadian Heritage.
Securing your Kubernetes cluster_ a step-by-step guide to success !KatiaHIMEUR1
Today, after several years of existence, an extremely active community and an ultra-dynamic ecosystem, Kubernetes has established itself as the de facto standard in container orchestration. Thanks to a wide range of managed services, it has never been so easy to set up a ready-to-use Kubernetes cluster.
However, this ease of use means that the subject of security in Kubernetes is often left for later, or even neglected. This exposes companies to significant risks.
In this talk, I'll show you step-by-step how to secure your Kubernetes cluster for greater peace of mind and reliability.
UiPath Test Automation using UiPath Test Suite series, part 4DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 4. In this session, we will cover Test Manager overview along with SAP heatmap.
The UiPath Test Manager overview with SAP heatmap webinar offers a concise yet comprehensive exploration of the role of a Test Manager within SAP environments, coupled with the utilization of heatmaps for effective testing strategies.
Participants will gain insights into the responsibilities, challenges, and best practices associated with test management in SAP projects. Additionally, the webinar delves into the significance of heatmaps as a visual aid for identifying testing priorities, areas of risk, and resource allocation within SAP landscapes. Through this session, attendees can expect to enhance their understanding of test management principles while learning practical approaches to optimize testing processes in SAP environments using heatmap visualization techniques
What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
Topics covered:
Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Builder.ai Founder Sachin Dev Duggal's Strategic Approach to Create an Innova...Ramesh Iyer
In today's fast-changing business world, Companies that adapt and embrace new ideas often need help to keep up with the competition. However, fostering a culture of innovation takes much work. It takes vision, leadership and willingness to take risks in the right proportion. Sachin Dev Duggal, co-founder of Builder.ai, has perfected the art of this balance, creating a company culture where creativity and growth are nurtured at each stage.
Neuro-symbolic is not enough, we need neuro-*semantic*Frank van Harmelen
Neuro-symbolic (NeSy) AI is on the rise. However, simply machine learning on just any symbolic structure is not sufficient to really harvest the gains of NeSy. These will only be gained when the symbolic structures have an actual semantics. I give an operational definition of semantics as “predictable inference”.
All of this illustrated with link prediction over knowledge graphs, but the argument is general.
Key Trends Shaping the Future of Infrastructure.pdfCheryl Hung
Keynote at DIGIT West Expo, Glasgow on 29 May 2024.
Cheryl Hung, ochery.com
Sr Director, Infrastructure Ecosystem, Arm.
The key trends across hardware, cloud and open-source; exploring how these areas are likely to mature and develop over the short and long-term, and then considering how organisations can position themselves to adapt and thrive.
Software Delivery At the Speed of AI: Inflectra Invests In AI-Powered QualityInflectra
In this insightful webinar, Inflectra explores how artificial intelligence (AI) is transforming software development and testing. Discover how AI-powered tools are revolutionizing every stage of the software development lifecycle (SDLC), from design and prototyping to testing, deployment, and monitoring.
Learn about:
• The Future of Testing: How AI is shifting testing towards verification, analysis, and higher-level skills, while reducing repetitive tasks.
• Test Automation: How AI-powered test case generation, optimization, and self-healing tests are making testing more efficient and effective.
• Visual Testing: Explore the emerging capabilities of AI in visual testing and how it's set to revolutionize UI verification.
• Inflectra's AI Solutions: See demonstrations of Inflectra's cutting-edge AI tools like the ChatGPT plugin and Azure Open AI platform, designed to streamline your testing process.
Whether you're a developer, tester, or QA professional, this webinar will give you valuable insights into how AI is shaping the future of software delivery.
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
Connector Corner: Automate dynamic content and events by pushing a buttonDianaGray10
Here is something new! In our next Connector Corner webinar, we will demonstrate how you can use a single workflow to:
Create a campaign using Mailchimp with merge tags/fields
Send an interactive Slack channel message (using buttons)
Have the message received by managers and peers along with a test email for review
But there’s more:
In a second workflow supporting the same use case, you’ll see:
Your campaign sent to target colleagues for approval
If the “Approve” button is clicked, a Jira/Zendesk ticket is created for the marketing design team
But—if the “Reject” button is pushed, colleagues will be alerted via Slack message
Join us to learn more about this new, human-in-the-loop capability, brought to you by Integration Service connectors.
And...
Speakers:
Akshay Agnihotri, Product Manager
Charlie Greenberg, Host
The Art of the Pitch: WordPress Relationships and SalesLaura Byrne
Clients don’t know what they don’t know. What web solutions are right for them? How does WordPress come into the picture? How do you make sure you understand scope and timeline? What do you do if sometime changes?
All these questions and more will be explored as we talk about matching clients’ needs with what your agency offers without pulling teeth or pulling your hair out. Practical tips, and strategies for successful relationship building that leads to closing the deal.
Dev Dives: Train smarter, not harder – active learning and UiPath LLMs for do...UiPathCommunity
💥 Speed, accuracy, and scaling – discover the superpowers of GenAI in action with UiPath Document Understanding and Communications Mining™:
See how to accelerate model training and optimize model performance with active learning
Learn about the latest enhancements to out-of-the-box document processing – with little to no training required
Get an exclusive demo of the new family of UiPath LLMs – GenAI models specialized for processing different types of documents and messages
This is a hands-on session specifically designed for automation developers and AI enthusiasts seeking to enhance their knowledge in leveraging the latest intelligent document processing capabilities offered by UiPath.
Speakers:
👨🏫 Andras Palfi, Senior Product Manager, UiPath
👩🏫 Lenka Dulovicova, Product Program Manager, UiPath
UiPath Test Automation using UiPath Test Suite series, part 3DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 3. In this session, we will cover desktop automation along with UI automation.
Topics covered:
UI automation Introduction,
UI automation Sample
Desktop automation flow
Pradeep Chinnala, Senior Consultant Automation Developer @WonderBotz and UiPath MVP
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
UiPath Test Automation using UiPath Test Suite series, part 3
Industrial Cooling
1. European Copper Institute
APPLICATION NOTE
INDUSTRIAL COOLING
Nico Vanden Broeck, Laborelec
October 2011
ECI Publication No Cu0117
Available from www.leonardo-energy.org /node/2020
3. Publication No Cu0117
Issue Date: October 2011
Page ii
CONTENTS
Summary ........................................................................................................................................................ 1
Introduction.................................................................................................................................................... 2
Dry Cooling ..................................................................................................................................................... 3
Advantages and disadvantages ..............................................................................................................................3
Energy Saving Possibilities on dry cooling systems ................................................................................................3
Evaporative cooling ........................................................................................................................................ 4
Advantages and disadvantages ..............................................................................................................................4
Cooling tower types................................................................................................................................................4
Open cooling tower ................................................................................................................................................4
Evaporative condenser and closed cooling tower..................................................................................................5
Hybrid cooling tower ..............................................................................................................................................6
Energy saving possibilities in the evaporative cooling domain ..............................................................................6
Why is a variable frequency drive so interesting? ...................................................................................6
Other aspects influencing the energy efficiency ......................................................................................7
Compression cooling....................................................................................................................................... 8
Theoretical and actual Carnot cycle .......................................................................................................................8
The Condenser .........................................................................................................................................9
The Expansion Valve.................................................................................................................................9
Evaporation Systems..............................................................................................................................10
Multiple compressor arrangement.......................................................................................................................10
Efficiency—COP ....................................................................................................................................................11
Ammonia versus other refrigerants .....................................................................................................................12
Energy saving possibilities on compression cooling .............................................................................................13
Conclusions................................................................................................................................................... 15
References.................................................................................................................................................... 15
4. Publication No Cu0117
Issue Date: October 2011
Page 1
SUMMARY
This paper introduces the subject of industrial cooling and discusses the most important energy savings that
are possible in this area.
Cooling is very expensive, so it is important that it is used only where necessary, and that only the most
efficient technology is used. For thermodynamic reasons, the energy efficiency of a cooling system increases
with decreasing temperature differential. It is therefore crucial to keep this differential as low as possible.
Three main types of cooling systems prevail in industrial environments: dry cooling, evaporative cooling, and
compression cooling. This paper explains their main working principles and characteristics. Other types, such
as absorption cooling, gas expansion, and thermo-electric cooling, are not treated in this application guide
because of their limited presence in industry.
Each system has its own application domain. The choice of the right cooling system is one of the important
initial decisions that must be taken in order to achieve maximum energy efficiency. Furthermore, this paper
discusses several specific energy saving actions for each of the three cooling systems.
Significant energy savings can be made by installing variable frequency drives on fans (dry cooling, evaporative
cooling), pumps (evaporative cooling, compression cooling), and compressors (compression cooling).
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INTRODUCTION
Cooling is, in general, an expensive form of energy. Industrial cooling typically consumes up to 7% of the
national electrical consumption in Western Europe.
The following rules of thumb are the basis for any industrial cooling concept:
The use of cooling should be reduced as much as possible
The most efficient technology must be used
The required temperature differential should be kept as low as possible
Three main types of cooling plant satisfy 90% of the industrial market: dry cooling, evaporative cooling, and
compression cooling (chiller). The useful temperature ranges of the three main types of cooling are illustrated
in Figure 1.
Figure 1: Main types of cooling and their usual operating temperature ranges.
40
35
25
20
T (°C)
EVAPORATIVE COOLING
(open, closed, hybrid,…)
DRY COOLING
COMPRESSION COOLING
(CHILLER)
(aircooled, watercooled)
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DRY COOLING
In dry cooling, fans drive ambient air over a warmer process fluid or gas (e.g. a glycol water solution) to cool it.
This type of cooling is used when the required low temperature is above the ambient air temperature, even if
only a few degrees.
Typical applications include the cooling system of compressors and condensers in chiller installations.
ADVANTAGES AND DISADVANTAGES
The advantages of dry cooling are:
No water and no water treatment equipment is required
Low maintenance requirements
Relative disadvantages when compared to evaporative cooling are:
The lowest attainable temperature depends on the dry temperature of the ambient air. The dry air
temperature is the temperature of the air measured with a thermometer freely exposed to the air but
shielded from radiation and moisture.
A large heat exchanging surface between the ambient air and the intermediate cooling medium is
needed.
The fans have a relatively high electrical energy consumption compared to those of a cooling tower
ENERGY SAVING POSSIBILITIES ON DRY COOLING SYSTEMS
Because cooling systems are generally located outside, fallen leaves, bird nests, and other debris can
obstruct free airflow through the heat exchanger. Regular cleaning of the heat exchanger and filters is
necessary to maintain high efficiency.
The air which is drawn through the dry cooler should be as cool as possible so air intakes should be
carefully placed to avoid any nearby heat sources such as warm gas exhausts.
The design requirement for a particular thermal power could be met by a small number of large fans,
or by a larger number of smaller fans. The latter is more expensive to buy but more energy efficient,
often resulting in a lower Total Cost of Ownership (TCO) over its life time.
The hot process fluid or gas should only be cooled as far as really necessary. The required electrical
power is directly proportional to the difference between the air temperature and the temperature of
the hot medium. If a final temperature of 40 °C is allowed, for example, it will be a waste of energy
and money to cool the process fluid to 35 °C.
The output of the cooling installation can be controlled by a simple on/off control, by a variable
frequency control of the fans, or by a cascade arrangement with on/off controls for each section. The
choice and design of this control will have an important influence on the energy efficiency and TCO of
the cooling system.
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EVAPORATIVE COOLING
This technique uses the latent heat of water vaporization to remove heat from the hot fluid or gas. At relative
air humidity below 100%, water evaporates, absorbing an amount of heat known as the latent heat of
vaporization and in this way cooling the remaining liquid or gas. The lower the relative humidity of the air, the
more efficient the process will be.
Relative humidity is measured using wet and dry bulb thermometers. The wet bulb thermometer is covered
with a sock and kept wet—that is, at a 100% relative humidity—by means of a wick and a water reservoir. The
dry bulb thermometer measures the temperature while freely exposed to the air, but shielded from radiation
and moisture. The relative humidity of the air can be derived from the difference between the wet bulb and
dry bulb temperatures using standard thermodynamic charts.
On dry summer days when the dry bulb temperature is above 25 °C, the fluid can be cooled typically to
temperatures around 21 °C.
ADVANTAGES AND DISADVANTAGES
Evaporative Cooling has the advantage of a better heat exchange compared to dry cooling, which results in:
A more compact installation (less ground surface needed)
Lower electrical consumption
A disadvantage is the additional water cost. It consists of a water treatment cost and a cost for replacing water
losses. The latter can be substantial with large cooling towers.
COOLING TOWER TYPES
There are three types of cooling towers:
Open cooling towers
Evaporative condenser and closed cooling towers
Hybrid cooling towers
OPEN COOLING TOWER
Figure 2: Example of an open cooling tower system.
The water that needs to be cooled is sprayed in at the top of the cooling tower and falls due to gravity. Air,
drawn upwards by the fan, makes contact with the falling water. The water partially evaporates absorbing heat
from the remaining droplets. The cooled water is collected in a water reservoir under the cooling tower, ready
to be returned to the process.
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Figure 3: Schematic diagram of an open cooling tower.
EVAPORATIVE CONDENSER AND CLOSED COOLING TOWER
Figure 4: Principal drawing of an evaporating condenser.
Evaporative condensers are integrated into many types of systems. The vapour to be condensed is circulated
through a coil, which is continually wetted on the outside by a recirculation water system, similar to that of an
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open cooling tower. Air blown into the tower causes a part of the water being circulated to evaporate,
removing heat from the gaseous refrigerant in the coil and causing it to condense.
The closed cooling tower has working principles similar to those of the evaporative condenser. The only
difference is that the medium cooled in the coil is simply water, instead of a particular gaseous refrigerant.
HYBRID COOLING TOWER
A hybrid cooling tower can, depending on the external conditions, function in three different regimes:
Dry mode (like a dry cooler)
Adiabatic mode (like a closed evaporative cooling tower)
Dry-Wet mode (combination, which yields the maximum cooling performance)
Due to the high initial price of the installation (roughly 5 times higher than an open cooling tower), hybrid
cooling towers become interesting if the water price exceeds 1.5 EUR/m³. Hybrid cooling towers are mostly
used when plume abatement is required.
The emphasis for this technology is on saving of water rather than energy.
ENERGY SAVING POSSIBILITIES IN THE EVAPORATIVE COOLING DOMAIN
WHY IS A VARIABLE FREQUENCY DRIVE SO INTERESTING?
The purpose of a fan in a cooling tower is to draw air through the tower so that the water can partially
evaporate. This airflow should be controlled, depending on the heat load of the cooling tower and the ambient
air temperature. Most fans on cooling towers are controlled either by using simple on/off control or by using a
2-speed motor. Depending on the average load of the cooling tower, substantial energy savings can be
obtained using a variable frequency drive on the fan.
For fans (as well as for pumps, etc.), the fluid flow is proportional to fan speed but energy consumption is
proportional to the cube of fan speed. For those machines, the following formula is true:
where
P is the electrical power in kW and
n is the number of revolutions of the fan
This has important consequences for the energy efficiency.
For example, by reducing the fan speed to 80% of the nominal flow, the power consumption will halve (i.e.
0.8
3
). This can be accomplished by lowering the frequency from 50 Hz to 40 Hz. To accomplish the same flow
(80% of nominal) using on/off controls would require an average power of 80% of nominal power. This means
that in this situation, the variable frequency drive will consume 37.5% (3/8) less than a simple on/off control.
The average saving potential of a variable frequency drive depends on the load pattern and the settings of the
cooling tower. The more variation in the load, the more advantageous a variable frequency drive becomes.
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OTHER ASPECTS INFLUENCING THE ENERGY EFFICIENCY
The whole process of cooling depends heavily on the efficiency of heat exchange with the environment. Most
water supplies are contaminated with other elements such as lime and organic material that can build up on
the heat exchanging elements and reduce efficiency. Depending on the quality of the water source, a variety of
water treatment measures will be necessary.
Pumps need to be properly sized and controlled by variable frequency drives. The use of throttling devices
should be avoided.
As previously explained, cooling becomes more expensive as the required temperature reduces. Every degree
of unnecessary cooling consumes more energy and water. For this reason, the required end-temperature
should be regularly reassessed.
Control systems that use bypasses to control the cooling demand are in no cases energy efficient.
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COMPRESSION COOLING
THEORETICAL AND ACTUAL CARNOT CYCLE
Compression cooling machines are used in a broad range of applications, from household refrigerators to large
industrial cooling systems. It makes use of a cooling refrigerant with a boiling point lower than the boiling
point of water.
The boiling point of a liquid decreased with reducing ambient pressure. By using compression and expansion, it
is possible to vaporize a liquid refrigerant at a low temperature and condense it at a higher temperature. At
the low temperature (evaporation temperature Tev), heat will be absorbed from the fluid which is to be cooled.
At the high temperature (condensing temperature Tcd), heat will be emitted to the surroundings.
Figure 5: Mollier diagram.
Figure 5 shows a Mollier diagram representing the various states of the refrigerant during the cooling cycle.
The main components of a compression cooling cycle are:
The compressor
The condenser
The expansion valve
The evaporator
The most common type of compressor is the piston compressor, but other types have won acceptance, e.g.
centrifugal and screw compressors. The piston compressor covers a very large capacity range, from small
single cylinder models for household refrigerators up to 8 to 10 cylinder models with large swept volumes for
industrial applications.
The smallest applications make use of a hermetic compressor, in which compressor and motor are built
together as a complete unit.
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For medium to large plants, the semi-hermetic compressor is the most common. It has the advantage that
shaft glands can be avoided, removing the need for a difficult maintenance operation. However, the design
cannot be used for ammonia plants, as this refrigerant attacks motor windings.
Still larger are Freon compressors and ammonia compressors, which are designed as ‘open’ compressors,
meaning with the motor outside the crankcase. The power can be transmitted to the crankshaft directly or
through a V-belt drive.
THE CONDENSER
The purpose of the condenser is to remove both the heat absorbed in the evaporator and the heat produced
by compression. If the condenser cools the refrigerant further than necessary, this is called sub-cooling.
One major advantage of sub-cooling is that the cooling capacity of the installation increases, as more heat can
be absorbed in the evaporator. Moreover, sub-cooling prevents the formation of flash gas. This phenomenon
takes place when the expansion valve is not fed with 100% liquid, but rather with a mixture of liquid and gas.
This can be caused by:
Inappropriate condenser (damaged condenser fins or an inadequately-designed condenser)
A decrease in the condensing pressure in the system upstream of the expansion valve
Unwanted ingress of warmer ambient air into the conduit.
Flash gas is a problem because it increases the volume of the mixture so that insufficient liquid can pass
through the orifice of the expansion valve. Hence, not all the available surface of the evaporator is used and
this causes instability of the cooling system. The presence of flash gas bubbles in the refrigerant can be
observed through a glass eyelet placed ahead of the expansion valve.
The disadvantages of too much sub-cooling are:
The capacity of the evaporator starts to decrease again from a certain level of sub-cooling
The evaporation pressure will decrease when the installation is lacking a proper regulator
The expansion valve operation becomes unstable.
Many different kinds of condensers are available on the market. The shell and tube condenser is used in
applications where sufficient cooling water is available. It consists of a horizontal cylinder with welded-on flat
end caps that support the cooling tubes. End covers are bolted to the end plates. The refrigerant condensate
flows through the cylinder, the cooling water through the tubes. The end covers are divided into sections by
ribs. The sections act as reversing chambers for the water so that it circulates several times through the
condenser. As a rule of thumb, the water heats up 5-10 °C with each passage through the condenser. A variant
of this is the plate heat exchanger. If it is desirable or necessary to cut down on the amount of water, an
evaporating condenser can be used. If no water at all is available for the condensing process, an air-cooled
condenser must be used. Both types of condenser were explained in the previous chapter.
THE EXPANSION VALVE
As previously explained, the main purpose of an expansion valve is to lower the pressure of the liquid.
Thermostatic expansion valves are the most common type utilized in direct-expansion refrigeration systems. It
regulates the refrigerant flow rate to the evaporator according to the degree of superheating of the gaseous
refrigerant leaving the evaporator. A thermostatic expansion valve consists of a valve body, a valve spring,
diaphragm, and a sensing bulb. The sensing bulb is placed at the outlet of the evaporator and is connected to
the upper part of the diaphragm by means of a capillary tube. If the temperature before the compressor is too
high, it means there is not enough flow through the evaporator to satisfy the cooling demand. In this case, the
orifice in the valve is enlarged to allow more refrigerant liquid to flow into the evaporator.
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Electronic expansion valves can provide more sophisticated, effective, and energy-efficient flow control than
thermostatic expansion valves. Currently, three types of electronic expansion valves are widely available: step
motor valves, pulse-width-modulated valves, and analogue valves.
Compared to the thermostatic expansion valves, the advantages of electronic expansion valves are the
following:
They provide a more precise temperature control (better product conservation)
They provide consistent superheat control under fluctuating head pressure
They are able to be operated at low head pressure during lower ambient air temperature
The have a higher energy efficiency
They enable the use of a floating high-pressure control. Such a control will reduce the condensing
temperature whenever possible, in this way increasing the efficiency of cooling installations. A
floating high-pressure control gives better results with an electronic expansion valve than with a
thermostatic one
EVAPORATION SYSTEMS
Many types of evaporators are available on the market, as various application-dependent requirements are
imposed upon them.
Evaporators for natural air circulation are used less and less because of the relatively poor heat transfer from
the air to the cooling tubes. Earlier versions were fitted with plain tubes, but it is now common to use ribbed
tubes or finned elements.
Evaporator efficiency increases significantly with the use of forced air circulation evaporators. With an increase
of air velocity, the heat transfer from air to tube is improved. As a result, a smaller evaporator surface can be
used for a given cold yield.
As the name implies, a liquid cooled heat exchanger cools liquid. The simplest method is to immerse a coil of
tube in an open tank. Closed systems in which tube cooler designs similar to shell and tube condensers are
employed, are increasingly common.
MULTIPLE COMPRESSOR ARRANGEMENT
Use of a single compressor to cool a cold storage room is not always the best solution. Indeed, a single
compressor could be over-designed for the major part of its operational life. This causes the evaporation
temperature to drop, with the following consequences:
Poor compressor efficiency
Short and frequent compressor runs
An increase of the drying effect at the evaporator side
More ice formation on the evaporator, requiring more defrosting cycles.
In addition to all of the above, energy consumption will increase.
For a well-designed installation, the following solutions can be considered:
Multiple stage compression
With a multiple stage compression system, bigger temperature differences (i.e. pressure ratios) can be
achieved with reduced energy consumption. As an example, a cooling machine with a condensing temperature
of 38 °C and an evaporating temperature of -40 °C, gives following results:
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One stage compression: 100% energy consumption
Two stage compression: 80% energy consumption
Three stage compression: 77% energy consumption
Because the initial investment cost increases with the number of stages, a careful analysis of all costs should
be carried out.
Parallel compressors, with one of them equipped with a variable frequency drive:
One of the compressors can be equipped with a variable frequency drive. This compressor should be twice the
size of the smallest compressor in the group, as it can only reduce its capacity to 50%.
Advantages:
Very accurate control of the evaporating temperature
Limitation of the number of start-up cycles
High efficiency
Disadvantages:
The compressor with capacity control will run most of the time
Higher initial investment cost (which pays itself back through lower energy consumption).
EFFICIENCY—COP
The efficiency of a chiller can be represented as the ratio between the thermal cooling capacity of the
installation and the electrical power used by the compressor. The efficiency is expressed as the Coefficient Of
Performance or COP. If an installation has a COP of 4, it means that for every unit of electrical energy, 4 units
of cooling energy are produced.
Because in reality there are several losses (heat and pressure), we have to multiply the COP of the theoretical
Carnot compression cycle with a factor . This factor varies between 0.5 and 0.6 for a well-proportioned
installation, but can go down to 0.2 in certain cases.
From the previous formula, we can draw an important conclusion: the efficiency is higher when the
condensing temperature is lower and the evaporation temperature is higher.
The following table presents some indications for the COP for cooling systems used to cool liquids. The
calculations are mostly based on the use of piston or screw compressors, but the values can also be applied to
chillers with centrifugal compressors. For better comparison, the condensing temperature is held stable at 40
°C. Temperature In/Out describes the temperatures of the fluid to be cooled at the evaporator inlet and outlet.
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Liquid Temperature
In/Out
(ºC)
Thermal Cooling
Capacity
(kWh/m
3
)
COP
Compressor
COP System Electrical Consumption
Compressor
kWh/m
3
Electric
system
kWh/m
3
Water (pure) 13/7 6.98 4.79 3.88 1.46 1.8
Water (pure) 11/5 6.98 4.51 3.65 1.55 1.9
Mono ethylene
10% 4/-2 6.90 3.54 3.02 1.95 2.3
20% -2/-8 6.57 2.91 2.51 2.26 2.6
30% -10/-18 6.3 2,4 2.11 2.62 3.0
Mono propylene
10% 4/-2 6.92 3.54 3.02 1.95 2.3
20% -2/-8 6.85 3.06 2.51 2.24 2.7
30% -10/-18 6.8 2.57 2.11 2.64 3.2
Calcium chloride
(CaCl2)
10% 4/-2 6.60 3.54 3.02 1.86 2.2
15% -2/-8 6.31 2.91 2.51 2.17 2.5
20% -8/-14 6.15 2.55 2.24 2.41 2.7
25% -14/-18 5.94 2.18 1.91 2.73 3.1
Table1: Indicative COPs for cooling systems.
COPsystem takes into account all electrical power necessary to produce cooling (including fans and pumps), while
COPcompressor only calculates using the electrical power consumption of the compressor.
AMMONIA VERSUS OTHER REFRIGERANTS
The design of refrigeration machines using ammonia is comparable with that of machines using halogenated
fluids. The components, however, are made of ordinary steel instead of copper, because copper, copper alloys,
and zinc are attacked by ammonia. Equipment adapted to ammonia is very specific and less widespread than
its halogenated fluid type counterpart.
Ammonia can be found in nature, but it is also synthesized in large quantities by the chemical industry. As a
refrigerant, it has the following advantages:
Good thermodynamic properties (heat/mass transfer) resulting in machines with leading performance
coefficients
A higher vaporization enthalpy, making it possible to produce temperatures as low as –60 °C
Chemical neutrality against components of the refrigeration system, excluding copper and its alloys,
as well as reliability in the presence of humid air and water
Better stability against oil
Easy leak detection, even small leaks (olfactive detection at 5 ppm)
No emissions that affect the atmospheric ozone layer and no Greenhouse Gas Emissions
The lowest purchase price of all refrigerants, namely 5 to 8 times cheaper as halogenated fluid (but
the installation cost will be higher because of the need for stainless steel)
Reduced pumping cost (embedded systems) and reduced piping dimensions for the same
refrigerating power
The restrictions associated with its use are due to the related hazards, in particular:
It is flammable, with an ignition temperature of 650 C
It is toxic at low concentrations in air (25 ppm)
The relatively high pressures require a higher pipe thickness than for halogenated refrigerants.
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ENERGY SAVING POSSIBILITIES ON COMPRESSION COOLING
Figure 6: Example of an evaporative chiller.
The first and most important energy saving action is proper maintenance of the installation, including a regular
cleaning of the condensers, a regular replacement of the compressor oil, and adequate defrosting of the
evaporators.
Other energy savings actions include:
Regularly checking the set point for the evaporation temperature. Efficiency increases with increasing
evaporation temperature.
Regularly checking the set point for the condensation temperature. Efficiency increases with
decreasing condensation temperature.
Opting for a centralized cooling system instead of several separate units. Bigger cooling installations
run at higher efficiency than smaller ones (amongst other things because of higher performance of
the individual parts).
Using evaporative cooling instead of compression cooling during wintertime. During the coldest
months of the year, evaporative cooling can often achieve very low water temperatures (down to 5
°C).
Using cold storage to avoid or compensate for peaks in cooling load.
Equipping all pumps and compressors that have a reduced or variable load with a variable frequency
drive.
In particular, installing a variable frequency drive on screw compressors. Screw compressors use a
capacity slide that can reduce the capacity of the compressor down to 10%. This capacity reduction
will be more efficient using variable frequency drives, as shown in the graph below.
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Figure 7: The influence of varying cooling capacity on the power consumption, with and without variable
frequency drive.
0
10
20
30
40
50
60
70
80
90
100
0 20 40 60 80 100
Cooling capacity (% of nominal)
Powerconsumption(%of
nominal)
capacity slide
frequency drive
Linear
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CONCLUSIONS
Cooling typically consumes 7% of electrical energy in Western Europe, and this figure is rising. Because it is
such a large energy user, the design and application of the cooling plant should be carefully considered. Large
energy savings can be achieved if certain general rules are applied:
Carefully assessing the cooling need to avoid over-dimensioning.
Choosing the right cooling technique. In some cases, it can be cost efficient to install two different
systems; for example evaporative cooling for the coldest winter months and compression cooling for
the remainder of the year.
Keeping the temperature differential low. For dry cooling systems, this means that the air intake
should be located at a cold spot. In compression cooling systems, it is important to choose
temperature set points as close to each other as possible while maintaining sufficient cooling
capacity.
Carefully selecting and dimensioning equipment during the design phase. The cheapest is often not
the most efficient.
Installing variable frequency drives on fans, pumps, and compressors.
Performing proper maintenance and cleaning actions on a regular basis.
Further elements that influence the energy efficiency include:
Dry cooling
o A large number of small fans are more energy efficient than a small number of large fans, but
has a higher purchasing cost. An optimum can be calculated to achieve the lowest life cycle
cost.
o As dry cooling systems are generally located outside, a regular cleaning of the heat
exchanger and the filters is necessary to maintain efficiency.
Evaporative cooling
o The energy efficiency of the heat exchange will increase with decreasing contamination of
the process water; best practice water treatment is therefore a crucial consideration.
o Control systems that make use of a bypass to control cooling demand are in no cases energy
efficient.
Compression cooling
o One centralized cooling system will be more energy efficient than a number of smaller
systems.
o In some cases, the use of cold storage to compensate for peaks in the cooling load will be
cost-efficient.
REFERENCES
[1] www.cti.org (Cooling Technology Institute), accessed October 2011
[2] American Society of Heating, Refrigerating and Air-conditioning Engineers Inc., Ashrae Handbook:
Refrigeration (SI Edition), Atlanta (USA), 2002
[3] S.K. Wang, Handbook of air conditioning and refrigeration, McGraw-Hill (Second Edition), New York
(USA), 2000
[4] European Commission, Integrated Pollution and Prevention Control (IPPC), Reference Document on
the application of Best Available Techniques to Industrial Cooling Systems, 2001