Storage of commodities at low temperature increases the shelf life. Proper understanding of storage system is necessary for desire cooling effect. Basic information regarding refrigeration is explained here. Design parameters are also give to be considered.
Cold storages are used for keeping perishashable food products. Design criteria for building and refrigeration concept for estimation of cooling load is decribed below.
Storage of commodities at low temperature increases the shelf life. Proper understanding of storage system is necessary for desire cooling effect. Basic information regarding refrigeration is explained here. Design parameters are also give to be considered.
Cold storages are used for keeping perishashable food products. Design criteria for building and refrigeration concept for estimation of cooling load is decribed below.
This presentation includes information about the evaporator, its history, working, classification, general types, methods of feeding, application, performance, thermal/process and design consideration, thermal design calculation, present and future vision regarding evaporators.
Single and multiple effective evaporator (mee)Sumer Pankaj
A multiple-effect evaporator, as defined in chemical engineering, is an apparatus for efficiently using the heat from steam to evaporate water.[1] In a multiple-effect evaporator, water is boiled in a sequence of vessels, each held at a lower pressure than the last. Because the boiling temperature of water decreases as pressure decreases, the vapor boiled off in one vessel can be used to heat the next, and only the first vessel (at the highest pressure) requires an external source of heat. While in theory, evaporators may be built with an arbitrarily large number of stages, evaporators with more than four stages are rarely practical except in systems where the liquor is the desired product such as in chemical recovery systems where up to seven effects are used.
The multiple-effect evaporator was invented by an African-American inventor and engineer Norbert Rillieux. Although he may have designed the apparatus during the 1820s and constructed a prototype in 1834, he did not build the first industrially practical evaporator until 1845. Originally designed for concentrating sugar in sugar cane juice, it has since become widely used in all industrial applications where large volumes of water must be evaporated, such as salt production and water desalination.
Multiple effect evaporation commonly uses sensible heat in the condensate to preheat liquor to be flashed. In practice the design liquid flow paths can be somewhat complicated in order to extract the most recoverable heat and to obtain the highest evaporation rates from the equipment.
Multiple-effect evaporation plants in sugar beet factories have up to eight effects. Six effect evaporators are common in the recovery of black liquor in the kraft process for making wood pulp.
This presentation includes information about the evaporator, its history, working, classification, general types, methods of feeding, application, performance, thermal/process and design consideration, thermal design calculation, present and future vision regarding evaporators.
Single and multiple effective evaporator (mee)Sumer Pankaj
A multiple-effect evaporator, as defined in chemical engineering, is an apparatus for efficiently using the heat from steam to evaporate water.[1] In a multiple-effect evaporator, water is boiled in a sequence of vessels, each held at a lower pressure than the last. Because the boiling temperature of water decreases as pressure decreases, the vapor boiled off in one vessel can be used to heat the next, and only the first vessel (at the highest pressure) requires an external source of heat. While in theory, evaporators may be built with an arbitrarily large number of stages, evaporators with more than four stages are rarely practical except in systems where the liquor is the desired product such as in chemical recovery systems where up to seven effects are used.
The multiple-effect evaporator was invented by an African-American inventor and engineer Norbert Rillieux. Although he may have designed the apparatus during the 1820s and constructed a prototype in 1834, he did not build the first industrially practical evaporator until 1845. Originally designed for concentrating sugar in sugar cane juice, it has since become widely used in all industrial applications where large volumes of water must be evaporated, such as salt production and water desalination.
Multiple effect evaporation commonly uses sensible heat in the condensate to preheat liquor to be flashed. In practice the design liquid flow paths can be somewhat complicated in order to extract the most recoverable heat and to obtain the highest evaporation rates from the equipment.
Multiple-effect evaporation plants in sugar beet factories have up to eight effects. Six effect evaporators are common in the recovery of black liquor in the kraft process for making wood pulp.
STEAM JET COOLING SYSTEM
Steam jet cooling system is a cooling technique which involves usage of steam and water for cooling purposes. In steam jet refrigeration systems, water can be used as the refrigerant. Like air, it is perfectly safe. These systems were applied successfully to refrigeration.
•Temperatures attained using water as a refrigerant are in the range which may satisfy air conditioning, cooling, or chilling requirements.
•Mostly low-grade energy and relatively small amounts of shaft work.
•This system are the utilization of mostly low-grade energy and relatively small amounts of shaft work.
•Not used when temperatures below 5°C are required.
The presentation gives a basic idea of cooling towers in big industries including the Power Plants. The performance of cooling towers and the commonenly used terms with reference to the cooling towers are also discussed at length. Care to be taken while in freezing temperatures in the European countries is also discussed.
Vapor compression refrigeration cycle, Refrigerants,
Coefficient of performance, Capacity, Factors affecting Refrigeration and Air conditioning
system performance and savings opportunities.
Vapor absorption refrigeration system: Working principle, Types and comparison with
vapor compression system, Saving potential
Students, digital devices and success - Andreas Schleicher - 27 May 2024..pptxEduSkills OECD
Andreas Schleicher presents at the OECD webinar ‘Digital devices in schools: detrimental distraction or secret to success?’ on 27 May 2024. The presentation was based on findings from PISA 2022 results and the webinar helped launch the PISA in Focus ‘Managing screen time: How to protect and equip students against distraction’ https://www.oecd-ilibrary.org/education/managing-screen-time_7c225af4-en and the OECD Education Policy Perspective ‘Students, digital devices and success’ can be found here - https://oe.cd/il/5yV
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Ethnobotany and Ethnopharmacology:
Ethnobotany in herbal drug evaluation,
Impact of Ethnobotany in traditional medicine,
New development in herbals,
Bio-prospecting tools for drug discovery,
Role of Ethnopharmacology in drug evaluation,
Reverse Pharmacology.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
The Art Pastor's Guide to Sabbath | Steve ThomasonSteve Thomason
What is the purpose of the Sabbath Law in the Torah. It is interesting to compare how the context of the law shifts from Exodus to Deuteronomy. Who gets to rest, and why?
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
3. Introduction
Evaporative cooling:- the function of an evaporator is to absorb heat
from the surrounding location or medium which is to be means of a
refrigerant.
• The temperature of the boiling refrigerant in the evaporator must always
be less than that of the surrounding medium so that the heat flows to the
refrigerant. The liquid refrigerant from the expansion valve enters into the
evaporator which it boils and changes into vapour.
• Evaporative cooling is a natural phenomenon that occurs when moving air
passes over a wetted medium or water source, i.e. fountain, river, sea,
shower, etc.
• The human body uses evaporative cooling through sweating to maintain a
constant body temperature.
4. Types of evaporative
cooling
Two types of evaporative cooling system:-
1. Direct evaporative cooling,
2. Indirect evaporative cooling.
Direct evaporative cooling:- is used to lower the temperature and
increase the humidity of air by using latent heat of evaporation, changing
liquid water to water vapor. In this process, the energy in the air does not
change. Warm dry air is changed to cool moist air.
• The heat of the outside air is used to evaporate water. The RH increases
to 70 to 90% which reduces the cooling effect of human perspiration. The
moist air has to be continually released to outside or else the air becomes
saturated and evaporation stops.
6. Working
• A mechanical direct evaporative cooler unit uses a fan to draw air through
a wetted membrane, or pad, which provides a large surface area for the
evaporation of water into the air.
• Water is sprayed at the top of the pad so it can drip down into the
membrane and continually keep the membrane saturated.
• Any excess water that drips out from the bottom of the membrane is
collected in a pan and recirculated to the top.
• Single stage direct evaporative coolers are typically small in size as it only
consists of the membrane, water pump, and centrifugal fan.
8. Indirect evaporative cooling
• Figure shows the schematic of a basic, indirect evaporative cooling
system. As shown in the figure, in an indirect evaporative cooling process,
two streams of air - primary and secondary are used.
• The primary air stream becomes cooled and humidified by coming in
direct contact with the wetted surface (o-o’), while the secondary stream
which is used as supply air to the conditioned space, decreases its
temperature by exchanging only sensible heat with the cooled and
humidified air stream (o-s).
• Thus the moisture content of the supply air remains constant in an
indirect evaporative cooling system, while its temperature drops.
• Obviously, everything else remaining constant, the temperature drop
obtained in a direct evaporative cooling system is larger compared to that
obtained in an indirect system, in addition the direct evaporative cooling
system is also simpler and hence, relatively inexpensive.
9. Advantages
• Less expensive to install and operate.
• Substantially lower operating and power costs. Energy savings can be as
high as 75 %.
• Ease of fabrication and installation.
• Lower maintenance costs.
• Ensures a very good ventilation due to the large air flow rates involved,
hence, are very good especially in 100 % outdoor air applications,
• Better air distribution in the conditioned space due to higher flow rates.
• Very environment friendly as no harmful chemicals are used
• Evaporative cooling increases humidity. In dry climates, this may improve
comfort and decrease static electricity problems.
10. Disadvantages
Compared to the conventional systems, the evaporative cooling systems
suffer from the following disadvantages:-
• Most evaporative coolers are unable to lower the air temperature as
much as refrigerated air conditioning can.
• High dewpoint (humidity) conditions decrease the cooling capability of the
evaporative cooler.
• Evaporative coolers require a constant supply of water to wet the pads
• Since the required air flow rates are much larger, this may create draft
and/or high noise levels in the conditioned space,
• Precise control of temperature and humidity in the conditioned space is
not possible,
• May lead to health problems due to micro-organisms if the water used is
not clean or the wetted surfaces are not maintained properly.
