Vapour Absorption Refrigeration System (with diagram)! The power utilized in vapour compression system is high grade energy i.e., electric power for running the compressor motor. In absorption refrigeration system, however, heat is directly utilized as source of energy. Of course, it may be preferable to utilize heat as such as it avoids undergoing through the various energy transformations required in [...]
In this article we will discuss about simple vapour compression refrigeration system. Introduction to Vapour Compression System: For a closed cycle of refrigeration employing the condensable refrigerant vapour, the following processes are required: (i) Compression of the vapour, thereby increasing pressure. (ii) Condensing these vapours and rejecting heating to the cooling medium (usually water or atmospheric air). (iii) Expanding the [...]
Large irrigation projects have been constructed all over the world for the purpose of irrigating agricultural lands through gravity flow systems. These projects usually consist of one or more storage reservoirs, diversion structures, canals and related structures, outlets and finally drainage facilities. The reservoirs constructed could also serve the purpose of flood control and hydroelectric power generation in which case [...]
With ever increasing demand of electric power, the existing transmission networks are found to be weak resulting in poor quality of unreliable supply. Also, it is realized that for expanding or enhancing the power transfer capability of the present transmission networks, huge sum of finances are required and sometimes even difficulties are encountered in finding right-of way for the new [...]
DC transmission possesses many technical and economic advantages over ac transmission. Some of the advantages are given below: Advantage # 1. Cheaper in Cost: Bipolar HVDC transmission lines require two-pole conductors while ac system requires 3 conductors to carry power. HVDC transmission can utilize earth return and, therefore, does not require a double circuit while EHV-AC transmission always requires a [...]
HVDC transmission is a strong alternative to EHV-AC transmission in some of the applications such as long distance high power transmission by overhead lines, under water transmission, transmission by underground cables, system interconnection by means of overhead lines or underground cables or back-to-back HVDC coupling stations, frequency conversion (50/60 Hz) and hence preferred. On the basis of applications, HVDC transmission [...]
The high voltage dc links may be classified into: 1. Monopolar Link 2. Bipolar Link 3. Homopolar Link. Type # 1. Monopolar DC Link: As the name suggests, monopolar link has only one conductor and return path is provided by permanent earth or sea. The line usually operates with negative polarity with respect to ground so as to reduce corona [...]
In HVDC transmission system or HVDC back-to-back coupling station, ac is converted into dc by means of a combination of converter-transformers and concerter valves. The conversion of ac into dc is called rectification. At the receiving end of the HVDC transmission line, dc is converted back to ac by means of converter valves and and converter transformers. The conversion of [...]
Here is an essay on ‘Electric Traction’ for class 9, 10, 11 and 12. Find paragraphs, long and short essays on ‘Electric Traction’ especially written for school and college students. Essay on Electric Traction Essay Contents: Essay on the Meaning of Electric Traction Essay on the Characteristics of Electric Traction Essay on the Different System of Electric Traction Essay on [...]
The following points highlight the four main accessories used for track electrification. The accessories are:- 1. Overhead Contact Wire 2. Conductor-Rail System 3. Current Collecting Shoes 4. Current Collectors for Overhead Contact Wire. 1. Overhead Contact Wire: The design of overhead contact wire as used for tramways, trolley buses and for railways of 1500 V and above is highly difficult [...]