What is The zeroth law of thermodynamics The zeroth law of thermodynamics states that if two thermodynamic systems are each in thermal equilibrium with a third, then they are in thermal equilibrium with each other.Two systems are said to be in the relation of thermal equilibrium if they are linked by a wall permeable only to heat, and do not change over time.[1] As a convenience of language, systems are sometimes also said to be in a relation of thermal equilibrium if they are not linked so as to be able to transfer heat to each other, but would not do so if they were connected by a wall permeable only to heat. Thermal equilibrium between two systems is a transitive relation.The physical meaning of the law was expressed by Maxwell in the words: "All heat is of the same kind".[2] For this reason, another statement of the law is "All diathermal walls are equivalent".[3]The law is important for the mathematical formulation of thermodynamics, which needs the assertion that the relation of thermal equilibrium is an equivalence relation. This information is needed for a mathematical definition of temperature that will agree with the physical existence of valid thermometers.[4](b)Define the The first law of thermodynamicsThe first law of thermodynamics is a version of the law of conservation of energy, adapted for thermodynamic systems. The law of conservation of energy states that the total energy of an isolated system is constant; energy can be transformed from one form to another, but cannot be created or destroyed. The first law is often formulated by stating that the change in the internal energy of a closed system is equal to the amount of heat supplied to the system, minus the amount of work done by the system on its surroundings. Equivalently, perpetual motion machines of the first kind are impossible.Conceptually revised statement, according to the mechanical approachThe revised statement of the first law postulates that a change in the internal energy of a system due to any arbitrary process, that takes the system from a given initial thermodynamic state to a given final equilibrium thermodynamic state, can be determined through the physical existence, for those given states, of a reference process that occurs purely through stages of adiabatic work.The revised statement is then For a closed system, in any arbitrary process of interest that takes it from an initial to a final state of internal thermodynamic equilibrium, the change of internal energy is the same as that for a reference adiabatic work process that links those two states. This is so regardless of the path of the process of interest, and regardless of whether it is an adiabatic or a non-adiabatic process. The reference adiabatic work process may be chosen arbitrarily from amongst the class of all such processes.This statement is much less close to the empirical basis than are the original statements,[14] but is often regarded as conceptually parsimonious in that it rests only on the concepts of adiabatic work and of non-adiabatic processes, not on the concepts of transfer of energy as heat and of empirical temperature that are presupposed by the original statements. Largely through the influence of Max Born, it is often regarded as theoretically preferable because of this conceptual parsimony. Born particularly observes that the revised approach avoids thinking in terms of what he calls the "imported engineering" concept of heat engines.[10](c)The Carnot cycleThe Carnot cycle is a theoretical thermodynamic cycle proposed by Nicolas Lonard Sadi Carnot in 1824 and expanded upon by others in the 1830s and 1840s. It provides an upper limit on the efficiency that any classical thermodynamic cycle can achieve during the conversion of thermal energy into work, or conversely, the efficiency of a refrigeration system in creating a temperature difference (e.g. refrigeration) by the application of work to the system. It is not an actual thermodynamic cycle but is a theoretical construct.Every single thermodynamic system exists in a particular state. When a system is taken through a series of different states and finally returned to its initial state, a thermodynamic cycle is said to have occurred. In the process of going through this cycle, the system may perform work on its surroundings, thereby acting as a heat engine. A system undergoing a Carnot cycle is called a Carnot heat engine, although such a "perfect" engine is only a theoretical construct and cannot be built in practice.[1]The Carnot cycle when acting as a heat engine consists of the following steps: Reversible isothermal expansion of the gas at the "hot" temperature, T1 (isothermal heat addition or absorption). During this step (1 to 2 on Figure 1, A to B in Figure 2) the gas is allowed to expand and it does work on the surroundings. The temperature of the gas does not change during the process, and thus the expansion is isothermal. The gas expansion is propelled by absorption of heat energy Q1 and of entropy \Delta S=Q_1/T_1 from the high temperature reservoir. Isentropic (reversible adiabatic) expansion of the gas (isentropic work output). For this step (2 to 3 on Figure 1, B to C in Figure 2) the mechanisms of the engine are assumed to be thermally insulated, thus they neither gain nor lose heat. The gas continues to expand, doing work on the surroundings, and losing an equivalent amount of internal energy. The gas expansion causes it to cool to the "cold" temperature, T2. The entropy remains unchanged. Reversible isothermal compression of the gas at the "cold" temperature, T2. (isothermal heat rejection) (3 to 4 on Figure 1, C to D on Figure 2) Now the surroundings do work on the gas, causing an amount of heat energy Q2 and of entropy \Delta S=Q_2/T_2 to flow out of the gas to the low temperature reservoir. (This is the same amount of entropy absorbed in step 1, as can be seen from the Clausius inequality.) Isentropic compression of the gas (isentropic work input). (4 to 1 on Figure 1, D to A on Figure 2) Once again the mechanisms of the engine are assumed to be thermally insulated. During this step, the surroundings do work on the gas, increasing its internal energy and compressing it, causing the temperature to rise to T1. The entropy remains unchanged. At this point the gas is in the same state as at the start of step 1.(d) Boyle's lawBoyle's law (sometimes referred to as the BoyleMariotte law, or Mariotte's law[1]) is an experimental gas law which describes how the pressure of a gas tends to decrease as the volume of a gas increases. A modern statement of Boyle's law is The absolute pressure exerted by a given mass of an ideal gas is inversely proportional to the volume it occupies if the temperature and amount of gas remain unchanged within a closed system.[2][3]Mathematically, Boyle's law can be stated aswhere P is the pressure of the gas, V is the volume of the gas, and k is a constant.The equation states that product of pressure and volume is a constant for a given mass of confined gas as long as the temperature is constant. For comparing the same substance under two different sets of condition, the law can be usefully expressed asThe equation shows that, as volume increases, the pressure of the gas decreases in proportion. Similarly, as volume decreases, the pressure of the gas increases. The law was named after chemist and physicist Robert Boyle, who published the original law in 1662.[4](f) Charles's lawCharles's law (also known as the law of volumes) is an experimental gas law which describes how gases tend to expand when heated. A modern statement of Charles's law is: When the pressure on a sample of a dry gas is held constant, the Kelvin temperature and the volume will be directly related.[1]this directly proportional relationship can be written as:where: V is the volume of the gas T is the temperature of the gas (measured in Kelvin). k is a constant.This law describes how a gas expands as the temperature increases; conversely, a decrease in temperature will lead to a decrease in volume. For comparing the same substance under two different sets of conditions, the law can be written as:The equation shows that, as absolute temperature increases, the volume of the gas also increases in proportion.(g)The KelvinPlanck statementThe KelvinPlanck statement (or the heat engine statement) of the second law of thermodynamics states that it is impossible to devise a cyclically operating device, the sole effect of which is to absorb energy in the form of heat from a single thermal reservoir and to deliver an equivalent amount of work.[1] This implies that it is impossible to build a heat engine that has 100% thermal efficiency.[2]The second law of thermodynamics states that in every real process the sum of the entropies of all participating bodies is increased. In the idealized limiting case of a reversible process, this sum remains unchanged. The increase in entropy accounts for the irreversibility of natural processes, and the asymmetry between future and past.While often applied to more general processes, the law technically pertains to an event in which bodies initially in thermodynamic equilibrium are put into contact and allowed to come to a new equilibrium. This equilibration process involves the spread, dispersal, or dissipation[1] of matter or energy and results in an increase of entropy.The second law is an empirical finding that has been accepted as an axiom of thermodynamic theory. Statistical thermodynamics, classical or quantum, explains the microscopic origin of the law.The second law has been expressed in many ways. Its first formulation is credited to the French scientist Sadi Carnot in 1824 (see Timeline of thermodynamics).Clausius statementThe German scientist Rudolf Clausius laid the foundation for the second law of thermodynamics in 1850 by examining the relation between heat transfer and work.[34] His formulation of the second law, which was published in German in 1854, is known as the Clausius statement: Heat can never pass from a colder to a warmer body without some other change, connected therewith, occurring at the same time.[35]The statement by Clausius uses the concept of 'passage of heat'. As is usual in thermodynamic discussions, this means 'net transfer of energy as heat', and does not refer to contributory transfers one way and the other.Heat cannot spontaneously flow from cold regions to hot regions without external work being performed on the system, which is evident from ordinary experience of refrigeration, for example. In a refrigerator, heat flows from cold to hot, but only when forced by an external agent, the refrigeration system.Kelvin statementLord Kelvin expressed the second law as It is impossible, by means of inanimate material agency, to derive mechanical effect from any portion of matter by cooling it below the temperature of the coldest of the surrounding objects.[36](h) An air compressorAn air compressor is a device that converts power (using an electric motor, diesel or gasoline engine, etc.) into potential energy stored in pressurized air (i.e., compressed air). By one of several methods, an air compressor forces more and more air into a storage tank, increasing the pressure. When tank pressure reaches its upper limit the air compressor shuts off. The compressed air, then, is held in the tank until called into use. The energy contained in the compressed air can be used for a variety of applications, utilizing the kinetic energy of the air as it is released and the tank depressurizes. When tank pressure reaches its lower limit, the air compressor turns on again and re-pressurizes the tank.There are numerous methods of air compression, divided into either positive-displacement or negative-displacement types.[1][2]According to the pressure delivered Low-pressure air compressors (LPACs), which have a discharge pressure of 150 psi or less Medium-pressure compressors, which have a discharge pressure of 151 psi to 1,000 psi High-pressure air compressors (HPACs), which have a discharge pressure above 1,000 psi(9)To produce 100% dry steam in an boiler and keep the steam dry throughout the piping system is in general not possible. Droplets of water will escape from the boiler surface due to turbulence and splashing when bubbles of steam break through the water surface. The steam leaving the boiler space will contain a mixture of water droplets and steam.In addition heat loss in the pipe lines condensates parts of the steam to droplets of water.Steam - produced in a boiler where the heat is supplied to the water and where the steam is in contact with the water surface of the boiler - contains approximately 5% water by mass.Dryness fraction of Wet SteamIf the water content in the steam is 5% by mass, then the steam is said to be 95% dry with a dryness fraction 0.95.Dryness fraction can be expressed: = ws / (ww + ws) (1) where = dryness fraction ww = mass of water (kg, lb) ws = mass of steam (kg, lb)Enthalpy of Wet SteamActual enthalpy of wet steam can be calculated with the dryness fraction - - and the specific enthalpy - hs - of "dry" steam picked from steam tables. Wet steam will always have lower usable heat energy than "dry" steam. ht = hs + (1 - ) hw (2) where ht = enthalpy of wet steam (kJ/kg, Btu/lb) hs = enthalpy of "dry" steam (kJ/kg, Btu/lb) hw = enthalpy of saturated water or condensate (kJ/kg, Btu/lb)Specific Volume of Wet SteamThe droplets of water in wet steam occupies a negligible space in the steam and the specific volume of wet steam will be reduced by the dryness fraction. vt = vs (3) where vt = specific volume of wet steam (m3/kg, ft3/lb) vs = specific volume of the dry steam (m3/kg, ft3/lb)