Its out of the optimum excess air fraction 10%-50%. The adjustment would be either
increase air flow or decrease fuel flow.
From Table 9.4, 40% excess air gives 8.4% CO2. From the table in handout, the
minimum temperature difference is 300 0F, an
GIVEN: Y = 20 m3;Tr = 25C, pr = 800 kPa;Tz = 20oC; = 600 kPa
FIND: How muchair was ventedto go fromstate1 to state2.
ASSUMPTIONS: air behaves an idealgas.
/ k g .K ( 2 0 +
1. A single zone AHU system is used to cool a single zone building in summer. The
building zone (including multiple rooms) has a design condition of 75 F DB and 50 %
RH. The building zone has a peak cooling load of 660,000 BTU/hr and its SHF = 0.8. If
P1= 36 psia
h1= 106.47 Btu/lb
P2= 200 psia
h2= 119.61 Btu/lb
P3= 200 psia
h3= 54.29 Btu/lb
Mixture of liquid and vapor
P4= 36 p