Load Calculation of Psychrometry MCQ Quiz in বাংলা - Objective Question with Answer for Load Calculation of Psychrometry - বিনামূল্যে ডাউনলোড করুন [PDF]
Last updated on Mar 12, 2025
Latest Load Calculation of Psychrometry MCQ Objective Questions
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Load Calculation of Psychrometry Question 1:
Statement (I): The estimation of exact cooling load calculations of space to be conditioned is important to know because it involves both the initial cost and operating cost.
Statement (II): The outside heat gain to conditioned space is called external load and the heat gain from inside the conditioned space is called internal load.Answer (Detailed Solution Below)
Load Calculation of Psychrometry Question 1 Detailed Solution
Before selecting the apparatus for the air - conditioner it is important to know the load requirements of the conditioned space, therefore the load calculations are important input for the initial cost of the conditioner and the operating cost also depends upon the loading conditions of the space.
Following loads are acting upon the components of a air - conditioner
External loads are due to the external environment, which includes heat loss or gain through Walls, roof, windows, ceiling etc.
Internal loads are loads due to occupants, lights appliances within the conditioned space..
Infiltration: Air leakage and moisture migration
System: Outside air, duct gain, reheat
Therefore both the statements are individually true.Load Calculation of Psychrometry Question 2:
In a theatre, heat is generated at the rate of 150 kJ/s due to the occupants, music and display system and other lighting. The rate of generation of excess moisture is 45 kg/hr. The theatre is provided with an air conditioner that is supplying conditioning at 600 m3/min. Calculate the Sensible heat factor for the theatre.
Answer (Detailed Solution Below) 0.81 - 0.83
Load Calculation of Psychrometry Question 2 Detailed Solution
Concept:
Sensible heat factor is defined as the ratio of sensible heat to total heat. Sensible heat is defined as the heat that causes a change in temperature and latent heat is the one that causes a change in phase and cannot be sensed. Total heat is the sum of sensible heat and latent heat.
\(SHF = \frac{{SH}}{{SH + LH}}\)
Calculation:
Sensible heat = 150 kJ/s
Latent heat = \(\frac{{45}}{{3600}} \times 2500 = 31.25\;kJ/s\)
Total heat = SH + LH = 181.25 kJ/s
SHF = 150/181.25 = 0.83
Load Calculation of Psychrometry Question 3:
Air entering the cooling coil 20% RH and 80% recirculating air. The outside air has enthalpy of 85 kJ/kg of da, and the room air has hi = 50.8 kJ/kg of da and the mixture has h1 = 57.64 kJ/kg of da. The air enthalpy corresponding to cooling coil temperature hs = 37.0 kJ/kg of da. The ratio of total cooling load to fresh air load is
Answer (Detailed Solution Below) 3.0 - 3.1
Load Calculation of Psychrometry Question 3 Detailed Solution
Total cooling load = h1 – hs = 57.64 – 37 = 20.64 kJ/kg of da
Fresh air load = 0.2 (85 – 50.8) = 6.84 kJ/kg of da
\(\frac{{Total\;cooling\;load}}{{Fresh\;air\;load}}\; = \;6.84/20.64\; = \;3.017\)
Load Calculation of Psychrometry Question 4:
40 \(\frac{{{m_3}}}{{min}}\) of air of sp.humidity 8.2 gm/kg of air, enthalpy 52.5 kJ/kg and sp.volume 0.87 m3/kg is passed over a cooling coil. Cooling coil capacity is 3.5 tonne of refrigeration, enthalpy 17.7 kJ/kg and sp.humidity 5.25 gm/kg. what will be sp.humidity of air leaving cooling coil ?
Answer (Detailed Solution Below)
6.85 gm/kg of air
Load Calculation of Psychrometry Question 4 Detailed Solution
\(messofair,{m_1} = \frac{{{V_1}}}{{{v_1}}} = \frac{{40}}{{0.87}} = 45.98\frac{{kg}}{{min}} = 0.77\frac{{kg}}{s}\)
Tonne of refrigeration
\({Q_1} = \frac{{TR \times 210}}{{60}} = {m_1}\left( {{h_1} - {h_2}} \right)\)
\(\frac{{3.5 \times 210}}{{60}} = 0.77\left( {52.5 - {h_2}} \right)\dot - 36.6\frac{{kJ}}{{kg}}\)
Sensible heat factor for cooling and dehumidification
\(SHF = \frac{{{h_1} - {h_c}}}{{{h_1} - {h_2}}} = \frac{{{w_1} - {w_c}}}{{{w_1} - {w_2}}}\)
\(\frac{{52.5 - 17.7}}{{52.5 - 36.6}} = \frac{{8.2 - 5.25}}{{8.2 - {w_2}}}\)
∴ w2 = 6.85 gm/kg of air