In part 1, the dry bulb temperature was relatively the same (22˚C).

Q2)

In part 1, the dry bulb temperature was relatively the same (22˚C). However, the rest of the values obtained kept changing because of the different instruments used. The specific volume, enthalpy and moisture content had no significant change in values. The relative humidity had a 6% difference between the sling and aspirated psychrometer and the humidity meter which would explain such differences for the dew point temperature altogether. In part 2, it is obvious that there are similar differences in values. By comparison, it is noticed that the dry bulb temperature at the outlet of the condenser is less than the room temperature. Thus, the dry bulb temperature of the evaporating outlet should be higher than the room temperature. The results values match this hypothesis, since the condenser is cooling the inlet air and the evaporator is heating the air. However, the moisture content is only changing when the humidifier is turned on, because at the cooling and heating process the moisture content is constant.

Q3)

The concept of Relative humidity is widely misunderstood by many people. The misunderstanding comes when people think that Relative humidity describe the water vapour content of the air. In fact, Relative humidity in itself does not indicate the actual amount of water vapour in the air because it depends on temperature. For example, an air parcel at a temperature of 10°C with RH = 100% contains less water vapour than an air parcel at a temperature of 25°C with RH = 50%. On the other hand, Dew Point Temperature (Td) represent the temperature were the air cannot hold more water (RH = 100% saturated). However, Relative humidity and Dew Point Temperature are very important parameters to determine the moisture content of the air from the psychometric chart. In part1, the Relative humidity recorded using the Humidity Meter = 40% & the Dew Point Temperature = 6.9˚C, using the psychometric chart the moisture content can be determine which is equal to 0.001 in our case and the same methodology should applied to part2.

Q4)

The moisture added to the air at the inlet can be calculated using the dry bulb temperature and the humidity ratio. The moisture content can be found from the psychometric chart when having those two values.

 

T=25 C    RH=55%    > W1 = 0.012 kg/kg

T=25 C     RH=45%   > W2 = 0.010 kg/kg

W1-W2= 0.012-0.010= 0.002 kg/kg

 

Q5)

          One instrument that is used to measure the dew point temperature is called the cooling coil. By running a refrigerant through the coil while air passes through it, it then finds the temperature at which dew starts to form on top of the pipe. With this value we could find the moisture content of the air from the psychometric chart.