Second Law Of Efficiency In Thermodynamics

A common measure of energy use efficiency is the first law efficiency , n1 . The first law efficiency is defined as the ratio of the output energy of the device to the input energy of the device. The first law is concerned only with the quantities of energy, and disregards in forms in which energy exists. It doesn't also discriminate between the energies available at different temperatures. It is the second law of thermodynamics which provides a means of assigning a quality index to energy. The concept of available energy or energy provides a useful measure of energy quality.

With this concept it is possible to analyze means of minimizing the consumption of energy to perform a given process, thereby ensuring the most efficient possible conversion of energy for the required task.

The Second law of efficiency n2 , of a process is defined as the ratio of the minimum available energy (or energy) which must be consumed to do a task divided by the actual amount of energy consumed in performing the same Task.

n2 = Min energy intake to perform the given task / actual energy intake to perform the same task.

n2 = Amin / A.

where A is the availability or energy.

A power plant converts a fraction of energy A or W max to useful work W. For the desired output of W,

Amin = W and A = W max.

Here,

I = Wmax - W and n2 = W / Wmax

Now,

n1 = W / Q1 = ( W / W max ) * ( Wmax / Q1)

n1 = n2 * n carnot

n2 = n1 / n carnot.

Since Wmax = Q1 ( 1- (To / T ))

n2 = W / Q(1-(To/T)) = n1 / n carnot

If work is involved, Amin = W ( desired ) and if heat is involved, Amin = Q (1- (To/T)).

If solar energy, Qr is available at a reservoir storage Temperature Tr and if Quantity of heat Qa is transferred by the solar collector at Temperature Ta, then

n1 = Qa / Qr

and n2 = energy output / energy input

n2 = Qa ( 1 - (To/Ta) ) / Qr (1 - (To/Tr))

n2 = n1 (((1-(To/Ta)) / (1- (To/Tr)))

Comments

ELECTRICAL COMPARATORS AND ITS WORKING

Electrical Comparators are used as a means of detecting and amplifying small movements of a work contacting elements. An electrical comparator consists essentially of a pick-up head or transducer for converting a displacement into a corresponding change in current and a meter or recorder connected in the circuit to indicate the electrical change, calibrated to show in terms of displacement. Generally, an amplifier is needed to provide the requisite sensitivity and to match the characteristics of different parts of the circuit. Electrical comparators can be classified according to the electrical principle used in the pick-up head. Most of the comparators use either a differential transformer, an inductance bridge, a strain gauge or a capacitor as a means of detecting movement of the gauging element. There are different types of electrical comparators. One kind called an electrolimit gauge is used to check or measure the outside diameter of a roll. The objec...

TOP POLLUTION RECORDED IN WORLD

CHERNOBYL NUCLEAR DISASTER (NUCLEAR POLLUTION) : In April 26,1986, the melt down of the Chernobyl nuclear reactor , in Russia, has leaked out the radioactive rays and radioactive materials. Effects : 1. In this Pollution nearly 2000 persons have been killed by the accident. 2. People suffered due to the illness such as, degeneration of the cells, severe bleeding, anemia, skin cancer. 3. Animals, Plants are also affected by nuclear radiation. MINAMATA EPIDEMIC (1953) : MARINE POLLUTION ( CASE STUDY ) Minamata is a small coastal village in Japan. The Chisso Chemical Company , which produces vinyl polymer plastics used organomercurial compound. The industry released its effluent into Minamata sea. The effluent containing mercury ions is converted into methyl mercury, which is highly toxic. The marine organisms like phytoplankton and zoo-planktons easily absorb the toxic methyl mercury compound. These organisms are consumed by small fishes and these are in ...

MELTING FURNACES FOR FERROUS METALS : CUPOLA AND ITS WORKING

Various types of melting furnaces are used in different foundry shops, depending upon the quantity of metal to be melted at a time, and the nature of work that is carried out in the shop. The primary objective in cupola is to produce iron of desired composition, temperature and properties at the required rate in the most economical manner. Besides, this furnace has many distinct advantages over the other types, e.g., simplicity of operation, continuity of production, and increased output coupled with a high degree of efficiency. Description Of a Cupola : The Cupola Furnace consists of a vertical, cylindrical steel sheet, 6 to 12 mm thick, and lined inside with acid refractory bricks or acid tamping clay. The refractory bricks or the tamping clay used consist of silicon oxide acid (SiO2) and alumina (Al2O3). The lining is generally thicker in the lower where the temperatures encountered are higher than in the upper region. The shell is mounted either on a brick work fo...

Mechinopedia For Mechanical Engineers

Search This Blog