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Tehnička termodinamika - Kemijsko-tehnološki fakultet

Tehnička termodinamika - Kemijsko-tehnološki fakultet

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TEHNIČKA TERMODINAMIKA__________________________________________<br />

za 10 kg vode → 22660 kJ<br />

−1<br />

qpregr.<br />

= h4<br />

− h3<br />

= hpregr.<br />

− h0.883<br />

′′ = 2835 − 2670 = 165 kJ kg<br />

za 10 kg vode → 1650 kJ<br />

ukupno 28004 kJ<br />

Primjer 5.2.<br />

3<br />

Koliko je topline potrebno da se 50 dm H2O temperature 25 °C ugrije<br />

do vrelišta, zatim potpuno ispari i pregrije na 250 °C ako je tlak 1.372 bar?<br />

Skica u T, s – dijagramu!<br />

Rješenje<br />

Slika P5.2.<br />

Q = Q +<br />

1 + Q2<br />

Q3<br />

−1<br />

q1 = h2<br />

− h1<br />

= 456.0 − 104.5 = 351.5 kJ kg<br />

−1<br />

q2 = h3<br />

− h2<br />

= h′′<br />

− h′<br />

= r = 2233 kJ kg<br />

240

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