HJD Institute of Technical Education and Research
Kera-Kutch
Department of Mechanical Engineering
REFRIGERATION AND AIR-CONDITIONING
ASSIGNMENT -2
Q1, On a particular day; the atmospheric air was found to have a dry bulb temperature of
30oC and wet bulb temperature of 18oC. The barometric pressure was observed to be 750
mm of hg. Using the table of psychometric properties of air, determine the relative
humidity, the specific humidity, the dew point temperature, the enthalpy of air per kg of
dry air and the volume of mixture per kg of dry air.
Q2, The humidity ratio of atmospheric air a 280C dry bulb temperature and 760 mm of
mercury is 0.016 kj/kg of dry air. Determine 1, partial pressure of water vapour; 2.
Relative humidity; 3, dew point temperature; 4, specific enthalpy; and 5, vapour density.
Q3, Determine the final dry bulb temperature and relative humidity of air washed with
recirculates spray water if the air is initially at dry bulb temperature 35 0C and 50%
relative humidity as it enters an air washer which has humidifying efficiency of 85%.
Q4, The atmospheric air at 40oC dry bulb temperature and 180C wet bulb temperature is
flowing at the rate of 100 m3/min through the space. Water at 18oC is injected into the
air stream at the rate of 48 kg/h. Determine the sp humidity and enthalpy of the leaving
air. Also determine the dry bulb temp, WB temp and relative humidity of the leaving air.
Q5, Atmospheric air at a dry bulb temperature of 160C and 25% relative humidity passes
through a furnace and then through a humidifier, I such a way that the final dry bulb
temperature is 300C and 50% relative humidity. Find the heat and moisture added to the
air. Also determine the sensible heat factor of the process.
Q6, One kg of air at 400C dry bulb temperature and 50%relative humidity is mixture with 2kg
of air at 200C dry bulb temperature and 200C dew point temperature. Calculate
temperature and specific humidity of the mixture.
Q7, 800 m3/min of recirculate air at 220C DBT and 100C dew point temperature is to be
mixed with 300 m3/min of fresh air at 300C DBT and 50% RH. Determine the enthalpy, sp
volume, humidity ratio and dew point temp of the mix.
Mr NISHANT R.SHUKLA
(SUBJECT IN-CHARGE)
Mr N. J.PATEL
(H. O. D MECH DEPT)