Exergy analysis of solar energy systems - Solar Energy Sciences and Engineering Applications - page 113

m 21 =˙ ˙ m 22 +˙ m 8 (3.3.24)

The energy balance equation for HHX is given below

Q HHX

m 17a h 17a ˙ + =˙ m 21 h 21 (3.3.25)

m 22 h 22 = Q HHX +˙

˙ m 23 h 23 (3.3.26)

The mass and energy balance equations for the condenser are given below

˙ =˙ +˙

m 2 m 6 m 3 (3.3.27)

m 2 h 2 + Q con =˙ ˙ m 6 h 6 +˙ m 3 h 3 (3.3.28)

Below mentioned equation is for energy balance of evaporator

Q eva

m 2a h 2a ˙ + =˙ m 1 h 1 (3.3.29)

The following energy balance equation is used to calculate the heat rejected by the
absorber.

m 11 h 11 + Q abs =˙ ˙ m 1 h 1 +˙ m 28 h 28 (3.3.30)

The thermal exergy of evaporator and HTG are defined as

1

T 0
T eva

Ex th,eva =

× Q eva − (3.3.31)

1

T 0
T HTG

Ex th,HTG =

× Q HTG − (3.3.32)

The energy and exergy COPs are calculated as

Q eva
Q HTG

COP en = (3.3.33)

+ W P

Ex th,eva
Ex th,HTG + W P

COP ex = (3.3.34)

Overall energy and exergy efficiencies are defined as

+ Q eva

m H 2 × ˙ HHV

η ov,en = × 100 (3.3.35)

I × b × L

Ex H 2 × Ex th,eva
Ex so

η ov,ex = × 100 (3.3.36)