martedì 1 settembre 2009
USING HOT WATER TO COOL: INDIRECT- FIRED ABSORPTION CHILLERS
The demand for cooling during summer, especially for what the tertiary is concerned, is growing steadily, both because more comfort is required and because of the noticeable rise of temperature in recent years. At the same time, the good traditional methods to allow a good comfort within the buildings seem to have been forgotten in the most recent construction techniques.
The growing use of cooling systems with compression chiller powered by electrical energy is certainly the main cause of the increase in the demand of electricity in summer, which sometimes leads to failures in power supply. The greenhouse gases, among which CO2, increase with energy production or with the loss of refrigerant fluids. Needless to say, this damages the environment and, at the same time, contributes to the vicious circle related to climatic changes. All this has lead to the need for real energy savings (D.L. 192) and to take into consideration the opportunity to use cooling systems with low primary energy needs which use renewable energy, such as thermal solar, biomass and photovoltaic systems.
There is ample choice of technologies for the passive cooling to improve indoor comfort and to drastically reduce the summer energetic need, both for buildings still to plan, and for existing building structures, both domestic and commercial.
Besides this, solar radiation is largely available in nature. The solar technologies for cooling are efficient and generally reliable both for the short and long term. These technologies do not make use of harmful refrigerant fluids (as a matter of fact, they generally use mixtures of water and LiBr) and have minimal energy consumptions in comparison to the traditional systems and therefore operating costs are lower.
Although absorption refrigerators powered by hot water –steam-combustible gases have been available to the market for more than a century, these were available only for elevated powers. In recent years the technology of the absorption cooling has made amazing progress, using new materials and electronic components, raising the quality standards both in terms of efficiency and reliability. Today we are witnessing a rapid development of enbloc frigorific absorption chillers of low power, hot water direct- fired (to 85-90°C). It is recognised that this opens interesting perspectives for their combined use with solar collectors.
It is impossible to foresee the course of the fuel prices of the traditional sources over a long period which is another element that has to be valued. These systems have a smaller environmental impact in comparison to the conventional systems of conditioning.
2. SPECIAL QUALITIES OF SYSTEMA’S ABSORPTION CHILLERS COMBINED WITH SOLAR COLLECTORS
Systema S.p.A. developed a unique absorption system in 2 different versions. The first one is an enbloc absorption chiller complete with all accessories (cooling tower, pumps, hydraulic connections, pipelines between absorption chiller and tower, valves, filters, pressure switch, differential pressure switch, control devices for temperature etc.). Being compact and completely enclosed, transport and installation are easy and fast. In the second version the cooling tower is separated from the absorption chiller and does not include the above mentioned accessories.
The absorption group must be selected according to needs of the building to be cooled, and to the quantity of hot water required.
The main advantages of using an absorption chiller powered by under vacuum solar collectors are:
• Use of thermal energy otherwise dissipated
The use of thermal energy allows lower costs and high energy savings. For these reasons absorption chillers are compared to energy recuperators;
• Environmental- friendly thanks to the use of a natural solution.
No harmful fluids are used. Furthermore, the energy used to power the absorption chiller has a low impact on the environment (low CO2 emissions);
• Low consumption of electric energy which is used exclusively for operation of circulation pumps;
• Simple and compact system thanks to enbloc equipment complete with all the necessary accessories, as a consequence, the installer will only have to connect pipelines for the hot water and conditioning systems. A further connection for makeup water must be provided to compensate for losses by evaporation from the cooling tower;
• Outdoor installation: space-saving solution;
• Modulation according to the thermal load thanks to inverters for managing the pumps. Thanks to Systema-Broad enbloc systems, frigorific power can be modulated from 20 to 100%. This allows water-supply/ electrical energy/ cooling water reduction, according to the customer’s needs;
• High efficiency (COP= 0,74)
The absorption chillers mod. SYBCTDH and SYBYDH have higher performances (COP= 0,74) than other conditioning systems of the same power which use hot water indirect-fired absorption chillers with low temperature (90°C);
• Long life-cycle and reduced need for maintenance: the reliability of the absorption chiller is due to minimal moving mechanical components and compressors;
• No noise and no vibration;
• Low fixed costs: since no electric cabin and transformer room are needed, the final user will have less fixed costs.
In order to satisfy several ranges of power capacity Systema can supply outdoor enbloc absorption chillers of high power or a series of absorption chillers can be installed using the cascade principle since the cooling tower is already included in the system.
The available powers capacity with temperature water of 98°C are: 45 kWs; 70 kWs; 175 kWs; 437 kWs; 656 kWs; 744 kWs; 875 kWs; 1094 kWs etc…
venerdì 22 maggio 2009
Despite all the problems related to copyright violation, I think that YouTube is an extremely funny and interesting tool to learn foreign languages. As a matter of fact, not only it is possible to listen to native-speakers and non native-speakers’ accents, but you can also find out cultural differences or similarities. In class we had fun in seeing how English people depict the Italian (but also Spanish, French etc...) way of speaking.
Although at the beginning I had a negative opinion about YouTube because of all the videos about bullying that news on TV are used to report, now I changed my mind. I think that YouTube is a good tool for my PLE and last semester I used it regularly to find out more about the ‘topic of the week’ or simply to add something funny to my blog. I also enjoyed watching the videos posted by my peers. Needless to say, I agree on the fact that music can help our learning process. As a matter of fact, I added to my blog a video with the lyric of a song some time ago and I commented that we can learn English also listening to music. For example, I learnt many poetic expressions listening to English songs, such as “pouring rain”, “roll the dice”, “bed of roses”, “two steps behind”, “you can never hide from the shadow that is creeping up beside you”, “it’s amazing how you can speak right to my heart”, “you can light up the dark”, “there is a truth in your easy” and “it can’t get worst than yesterday”, just to mention some of them.
In conclusion, we can say that, if used properly, YouTube can open many new worlds. I hope that you too can take advantage of this tool!
Have a nice day!
lunedì 18 maggio 2009
This is supposed to be our last post for this English course and I must admit that I am a bit sad because the years spent at the university seem to be almost over. Since I am not going to continue my studies (and thus my ‘formal learning’), I grasp the opportunity to reflect on my PLE (Personal Learning Environment). Needless to say, as Sarah (our English professor) told us, there is not a single definition of PLE and, since everyone has their own way of learning, there are no right or wrong solutions for our mind maps. In this post I would like to share with you my reflections as far as the English language is concerned and what could we do to achieve a higher level of competence.
In the image above you can see my mind map. I decided to use the world map as the background of my key concepts related to my learning process because English allows me to communicate with most of the people around the world. Therefore, our abilities and competences are the key to open new words and to discover new cultures. In today’s world more and more people do speak some sort of English (some people are native speakers, some use it as a second language and many other people learn it as a foreign language); as a consequence, English is becoming a global phenomenon and having a good command of it is, of course, extremely useful.
But the question is: is formal learning enough to learn a foreign language? Indeed, formal education such as school and university are important, but they are not the only tools available. I think that most of us had a narrow vision of the situations where we could learn a foreign language, and they coincided, more or less, with formal lessons, difficult translations, heavy grammar books and the like. And we were wrong. I wasn’t aware of the potential of Web 2.0 as a learning tool until this year. As my mind map reveals, the words that may be linked with formal learning are fewer if compared with other entries, such as Skype, YouTube, blogs etc.
I confess that it was not so easy to organize all the tools and the opportunities I have at my disposal to improve my language skills and make progress. At first I decided to divide the key nodes according to the kind of materials used (audio- paper- visual- virtual etc.), but then I changed my mind and organized the mind map into four main sections: INFORMATION, PLACES AND PEOPLE, CULTURAL SKILLS and LANGUAGE SKILLS. In my opinion this is the best way to integrate both formal and informal learning experiences and to connect a range of resources within a personally-managed space. As a matter of fact in the section INFORMATION I listed how I collect information and how I save it. I gather information from my teachers, but I rely also on the Web (Wikipedia, Delicious, OPAC online...).A part from paper notes, everything is stored on the Internet or in my computer (blog, bookmarks, tags, GoogleDocs...). PLACES AND PEOPLE are important, too. My knowledge of English now depends on my university education, my job as a clerk in the export department of a leading company in the heating sector (a way of enriching my vocabulary with technical words such as gasket, control panel, lead, ignition probe etc.), experiences abroad (scholarship in Malta, courses in English in Broadstair, international trade fairs...) and a virtual place: the Web 2.0, where I can ‘meet’ bloggers and share my experience with other people on social networks. CULTURAL SKILLS too play a great role for those who want to have a good command of a foreign language; in this section I grouped both formal ways of learning (literature courses, formal lessons etc.), but also informal tools (YouTube, movies, chats and forums). The latter outnumber the former. Last, but not least, I created a section for ‘pure’ LANGUAGE SKILLS, where I listed the four main areas of a language: reading, writing, speaking and listening. In this big area, my job now has a leading position for the development of my abilities and helps me to interact in English more effectively. Films in the original language and videos on YouTube together with media Websites and music are other opportunities I have to improve.
I noticed that ‘formal learning’ is only a minor part of my learning process, so when I will finish the University I would not have any problems in keeping my English updated and this is great! I also realized that giving private lessons could be an interesting way to refresh some grammar issues. As we discussed in class, learning is up to us. We have no excuses for giving up!
To conclude, during this semester I had the opportunity to see that everyone’s learning can benefit from a savvy use of technology. Thanks to the many tools offered by the Internet we can take control of and manage our own learning without much effort. I strongly believe that reflecting on our language-learning process is extremely useful because it gives us the opportunity to understand our strengths and our weaknesses while setting our targets for the future.
I hope to hearing from you soon,
Break a leg!
mercoledì 6 maggio 2009
In the Internet era, it seems that many people, especially young people, do not care for their privacy, yet we should bear in mind that the Internet is a public "place". Therefore, like in real life, on the Internet too
it is important not to give out personal data such as telephone numbers, usernames and passwords and many other details that should be kept secret. I do not publish personal photos and do not register to websites that I don't think safe. Moreover, when possible, I use a nickname and change my passwords regularly. I believe that no one should have their personal and private information shared with other people without their explicit consent, but unfortunately, this is what happens on some social networks, such as Facebook (see also the article mentioned in E-tivity 8). Even if we do our best to protect our privacy online, some friends of ours may publish online our photos, write our habits on the Facebook wall and our professors do publish our marks on the Web.
Since the Internet is an extremely useful tool, I think that the solution to privacy violation is not stopping using it. I would never do without reading online newspapers, sending e-mails to my friends, looking for interesting information quickly and without too much effort and surfing the Net. In my opinion, we should rather use antispyware and antivirus softwares and firewalls in order to protect our computer and ourselves from unauthorized access and external attaks and be cautious with suspicious emails and websites.
Internet is a synonym of democracy, so we all must lend a helping hand to prevent its misuse.
How to prevent identity theft - a video taken from YouTube.
venerdì 1 maggio 2009
This CONCISE reflecting blogging post aims to explain the features and potentialities of Google Docs.
In our last lab lesson we learnt something more about Google Docs, an online tool that enables people to share documents and collaborate using the Internet. One of the main advantages of this relatively new online resource is that people can have access to their files anywhere and anytime, provided they have an Internet connection. Working with Google Docs means simplify your work, especially if you cooperate with other people. Saving your documents, spreadsheets,and presentations on Google Docs makes you free to make changes to what you wrote while having the possibility to go back to previous versions you edited. As a matter of fact, like in Wiki pages, a section called "history" is always available. Unlike a wiki page, this web-based word processor is a close system. This means that in order to share files you must be invited from someone. This, of course, protects both the privacy and the data safety. It is clear that we do not want certain documents to be read - and maybe stolen - by anyone. Another difference between Google Docs and Wiki pages, is that with the former more than one people at a time can edit the same page and this is a great advantage!
During the second part of the lesson we tried to practice both with Google Docs and with APA style. We edited a file written by Professor Sarah Guth and Professor Francesca Helm and tried to improve the style of the references they used. Though this was not an easy task (also because of some problems with the access to the shared file "E-tivity 7" and with difficult kinds of sources to reference), Elena, Francesca and I managed to edit the works cited respecting the APA conventions for referencing. We noticed that the most difficult sources to list in the "Works Cited" section were web pages and the transcript of interviews pubished on-line, while books are relatively simple to referecing, provided you take care of punctuation, capital letters, italics and spacing... and all the rest ;-)
We noticed that Google Docs is not like Word, since it has less options and functionalities, but it is quite easy to use. All things considered, I think that this new tool could be useful when I have to work in group or when I have to discuss a Power Point presentation in different places. Since there is no more need of pen sticks and bulky attachments to store or share our files, I believe that more and more people will take advantage of this free word processor. It might have been extremely useful at the end of last semester, when I had to work together with some peers of mine to prepare our final Power Point presentation. Unfortunatly, we did not know that Google Docs existed and could also be used for free!
martedì 21 aprile 2009
Exploring APA and MLA websites, I learned that all ‘important’ words (verbs, nouns, pronouns, adjectives and adverbs) must be capitalised when quoting (this was a question I have been asking myself for a long time). Moreover, I found out that in the format by APA if you quote longer works you should either use italics or underline the title, but if you want to cite a shorter work, you are supposed to use quotation marks. Honestly speaking, I find this difference quite silly. Yet, if this is the general rule, I will do my best to follow it! Personally, I prefer using italics rather than underlining, but surprise surprise... according to MLA style the contrary would be much better. I agree with Modern Language Association when it suggests people use “Work Cited” or “Annotated Works Cited” instead of the more generic “Bibliography”. I finally learned that indentation of a long quotation must be five spaces from the left margin and the double-spacing should be maintained. Needless to say, APA and MLA are quite different: here below I would like to mention just a couple of examples. MLA thinks that one should not abbreviate the name of the authors, while according to APA it is preferable to write the authors’ surnames first and then their names’ initials. Also the right place for the year of publication of a work is different: while according to MLA it must be written at the very end, in the APA style it should be inserted after the author’s name. Last but not least, the use of ‘&’ before the last author’s name is suggested by the Modern Language Association, but the American Psychological Association believes that in such a case an ‘and’ would be definitely more appropriate.
In my B.A. thesis I followed my supervisor’s advice and used the single-spacing for long quotation and, as far as indentation was concerned, I did it according to my own taste. I did not used ampersands because I feel that they are more used in commercial contexts, rather than in academic ones. All things considered, the style I used was a mix of APA and MLA styles.
In conclusion, I believe that we should practice a lot not just before our final dissertation, but also on other occasions. Writing academic pieces of work is not an easy task at all and, beside being careful, you also have to carve our plenty of time in order to come up with a clear and precise work. I hope to learn how to quote correctly as soon as possible.