1) Refrigeration and air conditioning systems use a vapor compression cycle to transfer heat from cool spaces to warm spaces. They circulate a refrigerant between an evaporator, compressor, condenser and expansion valve.
2) In the evaporator, the refrigerant absorbs heat from cool spaces and changes state from liquid to vapor. The compressor increases the refrigerant's pressure and temperature. In the condenser, the refrigerant releases heat to warm spaces and changes state from vapor to liquid.
3) The expansion valve reduces the refrigerant's pressure, lowering its temperature. This allows it to absorb more heat in the evaporator and continue the cooling cycle. Proper refrigerant selection and system design are important
Refrigeration and Air Conditioning System ComponentsAjaypalsinh Barad
The ppt contains detailed study of all the components used in refrigeration and air conditioning system with neat sketches and description. It is well formed as per the syllabus of GTU
Experimental Investigation of Water Cooler Test Rig Using R-22 as RefrigerantIJMERJOURNAL
ABSTRACT: This paper describes Water Cooler; a tool that aggregates shared internal social media and cross-references it with an organization’s directory. We deployed Water Cooler in a large global enterprise and present the results of a preliminary user study. Despite the lack of complete social networking affordances, we find that Water-Cooler changed users’ perceptions of their workplace, made them feel more connected to each other and the company, and redistributed. Water coolers work on vapour compression refrigeration cycle. The behavior of performance parameters of a simple vapour compression refrigeration system were studied while it’s working under transient conditions occurred during cooling of a fixed mass of brine from initial room temperature to sub-zero refrigeration temperature. The effects of different lengths of capillary tube over these characteristics have also been investigated. The main advantage of our project is to cool the water with help of test rig.
Refrigeration and Air Conditioning System ComponentsAjaypalsinh Barad
The ppt contains detailed study of all the components used in refrigeration and air conditioning system with neat sketches and description. It is well formed as per the syllabus of GTU
Experimental Investigation of Water Cooler Test Rig Using R-22 as RefrigerantIJMERJOURNAL
ABSTRACT: This paper describes Water Cooler; a tool that aggregates shared internal social media and cross-references it with an organization’s directory. We deployed Water Cooler in a large global enterprise and present the results of a preliminary user study. Despite the lack of complete social networking affordances, we find that Water-Cooler changed users’ perceptions of their workplace, made them feel more connected to each other and the company, and redistributed. Water coolers work on vapour compression refrigeration cycle. The behavior of performance parameters of a simple vapour compression refrigeration system were studied while it’s working under transient conditions occurred during cooling of a fixed mass of brine from initial room temperature to sub-zero refrigeration temperature. The effects of different lengths of capillary tube over these characteristics have also been investigated. The main advantage of our project is to cool the water with help of test rig.
Computer Hardware Servicing Learner's Material Grade 10Bogs De Castro
This material is for CHS learners only. It can be used as a resource materials.
It is owned by DepEd. All copyright is from the publishers, creators, and owners.
Curso practico personalizado.
Horarios a elegir de acuerdo a TU disponibilidad, Se coordina previamente
Informes: 980954916 LIMA- PERU - San Juan de Miraflores
Correo:basinyer@hotmail.com
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Quality defects in TMT Bars, Possible causes and Potential Solutions.PrashantGoswami42
Maintaining high-quality standards in the production of TMT bars is crucial for ensuring structural integrity in construction. Addressing common defects through careful monitoring, standardized processes, and advanced technology can significantly improve the quality of TMT bars. Continuous training and adherence to quality control measures will also play a pivotal role in minimizing these defects.
COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
Vaccine management system project report documentation..pdfKamal Acharya
The Division of Vaccine and Immunization is facing increasing difficulty monitoring vaccines and other commodities distribution once they have been distributed from the national stores. With the introduction of new vaccines, more challenges have been anticipated with this additions posing serious threat to the already over strained vaccine supply chain system in Kenya.
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
2. Introduction
• Cooling of food stores and cargo
• Cooling of electronic spaces and equipment
• CIC (computers and consoles)
• Radio (communications gear)
• Radars
• Servers
• Sonar
• Electronic controls
• Air conditioning for crew comfort
3. Refrigeration
• Refrigeration may be defined as the process of achieving and maintaining a temperature below
that of the surroundings, the aim being to cool some product or space to the required temperature
• The rating of a refrigeration machine is obtained by refrigerating effect or amount of heat
extracted in a given time from body
• It is defined as the refrigerating effect produced by melting of 1 tonne of ice from and at 0°C in
24 hours.
• Since L = 336kJ/kg
• 1 TR= 3.88kW
5. Refrigerator
Throttle
Compressor
QR/Q2
Refrigerator
W
• In nature, heat flows from high-temperature regions to low-temperature ones
• The reverse process, however, cannot occur by itself
• The transfer of heat from a low- temperature region to a high-temperature one requires special
devices called refrigerators
Refrigerators are cyclic devices, and the working fluids used in the cycles are called refrigerant
Condenser
QC/Q1
6. Refrigeration Systems
• Vapor Compression Refrigeration (VCR): uses mechanical energy
- Highly compressed fluids tend to get colder when allowed to expand
- If pressure high enough
- Compressed air hotter than source of cooling
- Expanded gas cooler than desired cold temperature
Condenser
Evaporator
High Pressure
Side
Low
Pressure
Side
Compressor
Expansion Device
1
2
3
4
7. • Point 1-2 (Evaporation): Constant pressure and temperature are maintained, i.e., saturation.
When heat is transferred at saturation, the result is a change in phase
• Point 2-3 (Compression): Compressing the gaseous Freon produces a concomitant increase in
thermal energy represented by a rise in the enthalpy and the temperature of the Freon
- This is the heat of compression resulting from the added energy to the Freon vapor
- Compression provides the thermal driving head to sustain the flow of Freon through the cycle
• Point 3-4 (Condensation): In passing through the dome from the right side to the left, the
refrigerant cools from 51°C to 40°C and changes phase from a superheated vapor to a slightly
sub-cooled liquid
• Point 4-1 (Expansion): The refrigerant is expanded by passing through an expansion valve where
its pressure is reduced from 10 bar to 1.5 bar.
- In the process of expanding, the Freon cools from 40°C to -20°C (cold of expansion) and
crosses into the dome where both saturated liquid and gaseous Freon can coexist
- About 25% of the fluid vaporizes into a gas during the process
8. Vapor Compression Refrigeration Cycle
High Pressure
Side
Low Pressure
Side
Compressor
Expansion Device
1
2
3
4
Low pressure liquid refrigerant in
evaporator absorbs heat and changes
to a gas
The superheated vapor
enters the compressor
where its pressure is
raised
The high pressure superheated gas is
cooled in several stages in the condenser
Liquid passes through
expansion device, which
reduces its pressure and
controls the flow into the
evaporator
Evaporator
Condenser
9. Typical Refrigeration Cycle
• Components:-
- Refrigerant
- Evaporator/Chiller
- Compressor
- Condenser
- Receiver
- Thermostatic expansion valve (TXV)
• Choice of compressor, design of condenser, evaporator
determined by
• Refrigerant
• Required cooling
• Load
• Ease of maintenance
• Physical space requirements
• Availability of utilities (water, power)
10. Refrigerant
• Desirable properties:
• High latent heat of vaporization - max cooling
• Non-toxicity (no health hazard)
• Desirable saturation temp (for operating pressure)
• Chemical stability (non-flammable/non-explosive)
• Ease of leak detection
• Low cost
• Readily available
• Commonly use FREON (R-12, R-114, etc.)
11. Compression and Compressor
• The low pressure, superheated refrigerant vapor is discharged from the evaporator to the suction
side of the compressor
• The compressor is the mechanical unit which keeps the refrigerant circulating through the system
by increasing the fluid’s pressure and thermal potential energies
• In the compressor (either reciprocating or centrifugal), the refrigerant is compressed from a low
pressure vapor to a high pressure vapor, and its temperature rises accordingly from the heat of
compression
• This increase in energy provides the driving force to allow the refrigerant to flow through the
system
12. Evaporation
• The boiling point of the refrigerant under low pressure in the evaporator is extremely low, much
lower than the temperature of the spaces in which the cooling coils are installed
• The temperature differential between the -20.5°C refrigerant in the coils and the air in the
freeze box slightly above -17°C causes heat to be transferred from the freeze box to the
refrigerant
• It absorbs its latent heat of vaporization from the surroundings, thereby cooling the space
• The refrigerant continues to absorb heat until all the liquid has boiled and vaporized
• To ensure all the refrigerant changes phase to vapor, the refrigerant must be slightly superheated
• As a rule, 6°F to 10°F of superheat is added to the refrigerant
• The refrigerant leaves the evaporator as a low pressure superheated vapor, having cooled the
space
• The remainder of the cycle is concerned with disposing of this heat and getting the refrigerant
back into a liquid state so that it can again vaporize in the evaporator and thus again absorb heat
from the space
13. Evaporator/Chiller
• Located in space to be refrigerated
• Cooling coil acts as an indirect heat exchanger
• Absorbs heat from surroundings and vaporizes
• Latent Heat of Vaporization
• Sensible Heat of surroundings
• Slightly superheated (-12°C) - ensures no liquid carryover into compressor
14. Condensation and Condenser
• The refrigerant must be thermodynamically returned to its starting point as a high pressure (10
bar) and high temperature (40°C) sub-cooled liquid from a higher temperature (-4°C) superheated
vapor
• There is a significant amount of heat to extract in transforming the refrigerant from a gas to a
liquid in the form of latent heat of condensation (LHC)
• Since this extraneous heat must be disposed, a heat exchanger is used to absorb the LHC and
discharge it overboard
• The heat removal from the refrigerant causes it to condense into a liquid at a constant pressure of
10 bar
• The refrigerant, still at a high pressure, is now a sub-cooled liquid ready to commence the process
again
• From the condenser, the refrigerant flows into a receiver, which serves as a storage place for the
liquid refrigerant and as a seal between the high and low pressure sides of the refrigerant loop
• From the receiver, the refrigerant returns to the expansion valve and the cycle begins again
• All refrigeration and air conditioning systems follow this simple process no matter what type of
refrigerant is used. The operating parameters will change, but it still is the same basic cycle.
15. Expansion
• Liquid refrigerant enters the expansion valve at high pressure.
• The refrigerant leaves the outlet of the expansion valve at a much lower pressure and enters the
low pressure side of the system
• Because the pressure release has decreased the refrigerant’s potential energy, the liquid
refrigerant manifests this energy conversion by beginning to boil and to flash into vapor.
• The refrigerant is still saturated and at a very low temperature of -20°C entering the evaporator,
or chiller, coils
• It is now a mixture of liquid and vapor refrigerant. This temperature gives us a thermal
differential to cool, or keep cool, a space which must be maintained at required temperature
• The refrigerant is now ready to absorb the unnecessary heat from the space by entering the
evaporator coils located in the space to be cooled
16. Expansion Device
• Thermostatic Expansion Valve (TXV)
• Liquid Freon enters the expansion valve at high pressure and leaves as a low pressure wet vapor
(vapor forms as refrigerant enters saturation region)
• Controls:
• Pressure reduction
• Amount of refrigerant entering evaporator controls capacity
refrigerant as a saturated
mixture of liquid and vapor
Cooling Coils
EXPANSION VALVE
17. Receiver
• Temporary storage space & surge volume for the sub-cooled refrigerant
• Serves as a vapor seal to prevent vapor from entering the expansion valve
18. Air Conditioning
• Purpose: maintain the atmosphere of an enclosed space at a required temp, humidity and purity
• Refrigeration system is at heart of AC system
A Typical Window Air Conditioner