i have the authority to talk about enthalpy, entropy, adiabatic compression, saturation, humidity, irreversible expansion.... in short......

REFRIGERATION and AIR CONDITIONING

aying!

I am starting to miss college. I miss the board works, exams, reports, and everything. I want to go back. weee. That's why i am planning to take the post-masteral course that will be offered in Bicol University (BU) - College of Engineering next year.


Meanwhile, to feed my nostalgic emos, let me recall our basic lessons on Refrigeration and Air Conditioning before. Para sa mga curious kung ano ang mga ginagwa namin sa tribu. Patikim tungkol sa buhay Engineering....

REFRIGERATION and AIR CONDITIONING

Refrigeration is the study of process dealing with reducing and maintaining the temperature of a space or material below the temperature of the surroundings.

This subject has been one of our nightmares during our last days in college. Buti na lang nakapasa rin after daily "katayan" sa board work under a professor na nakakatanggap ng death threats sa mga estudyante nya (malamang dahil sa sobrang hirap ng subject at pagkaTERORista nya! aying!). One problem per day ang isosolve mo sa harap ng black board hawak ang chalk at calculator at dapat after 10 or 15 minutes tapos kana. After that, you must clearly explain your solution.

This is a Vapor Compression Refrigeration System.
(Compressor, Condenser, Expansion valve, Evaporator)

You can see four points and four components. If you are familiar with the refrigerant (as if naman ahihi), which is the working substance for a refrigeration system, yun ung dumadaan sa apat na components na yan.



So from point 1, the refrigerant (commonly freon) passes through the Compressor under adiabatic compression. From saturated vapor to the condenser pressure, teh refrigerant is now ready to enter the condenser from point 2. Gets? With the reversible rejection of heat at constant pressure, the refrigerant undergoes desuperheating and condensation from point 2 to 3. Mas maiintindihan natin tong mga to using the P-H and T-S diagram sa baba. Sa una mahirap but later on, you will surely enjoy it.




From point 3-4, irreversible expansion at constant enthalpy happens so that the refrigerant becomes saturated until it reaches the necessary evaporator pressure. Finally, from point 4-1, reversible addition of heat at constant pressure takes place in the evaporator. The process repeats on and on. Naintindihan mo na? yehey!

Mayon Volcano? hindi noh! pakarai!

HILO KANA BA? argh!

Basta ganun lang un. Paulit ulit lang ang process. From compression, iko-condense ang refrigerant, then ie-expand, then ibe-vaporize, and the process repeats on and on.

Now sa TS and PH diagrams, you can observe that there are horizontal, vertical, and curve lines. Ung bundok bundukan jan, un ung saturation line. It entails the critical points kung saan ung substsance is about to condense or about to vaporize. Sa PH, the horizontal lines depict constant pressure while the vertical describe a process at constasnt enthalpy. Ung curve dun nagsasabing constant entropy sya. Sa TS naman, horizontal for constant temperature and vertical for constant entropy. see madali lang diba (argh!).

Mukang nag-enjoy ka ha. Next time iba naman. ahihi...

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