Welcome toChina Automotive Air Conditioning Business Net
Add to Favorites | Chinese
The thermodynamic law related the car
From;    Author:Stand originally

The refrigeration unit of car air conditioning moves in, the mutual changeover between the energy that often produces a different form or deliver, make refrigeration agent condition produces change. For instance: The engine in the car is OK the chemical energy translate into fuel axial mechanical energy, pass the brace linkage mechanism of compressor next, will mechanical result passes a piston to undertake compression to refrigeration agent steam, made change turns into heat energy, this part heat energy passes the air outside the car again in condenser. This a series of quantity of heat is delivered or move waits for a quantity. That is to say, caloric is delivered, perhaps be in mechanical result and transition of quantity of heat, energy summation keeps changeless. This is thermodynamic the meaning of the first law.
One, internal energy:
The summation of the kinetic energy of element of labour qualitative interior and potential energy is called thermodynamic can. From the point of microcosmic angle, of material thermodynamic the kinetic energy that can include molecular shift, rotational, oscillatory campaign and a because of interaction force existing between the element some potential energy. Thermodynamic the sheet that can be temperature is worth function. Thermodynamic can be a condition parameter that cannot determine directly, “u” of commonly used symbol expresses, the unit is K J/kg. Calculate only normally thermodynamic can opposite change, what define the gas when 0 ℃ condition is thermodynamic can be 0.
2, enthalpy:
In operating mode of refrigeration air conditioning, a lot of hot project facilities, if evaporator, condenser is,in labour the condition that qualitative ceaseless inpour pours out of allots the move of raw energy and exchange. Still show in process of work qualitative flow it is certain to have drive result. Alleged enthalpy, what be equal to unit quality work to be had character namely is thermodynamic can mix drive result the sum, express with “i” , the unit is K J/kg.
So enthalpy can express with next type: Pv of + of I = U
This shows, enthalpy is be combined by U of 3 condition parameter, P, V and become, also be parameter of a condition. In the heating power computation of refrigeration air conditioning, enthalpy has extremely extensive effect.
The absolute value of enthalpy decides very hard, also did not ask to go out surely in fact, because need understanding worker worker only normally,change to be worth metabolic value to the enthalpy when another condition by a condition character. In refrigeration operating mode, the enthalpy value agent of refrigeration of 0 ℃ saturated liquid state sets artificially for 100. Labour of all sorts of state ground refrigeration pledge enthalpy is worth can check in concerned chart.
It is OK that refrigeration agent labour pledges the result in refrigeration equipment heats up changeover, heating power to calculate simplify accordingly calculate into enthalpy estimation. Specific means is:
Previous12 Next