An air conditioning system is used to provide cooling for a small office building in the summer. Cool dry air (State 2) is supplied to the conditioned space (State 3) to balance the total cooling load (QT for the space. Air exiting through return ducts is either recirculated or exhausted from the building. The recirculated air is mixed with a specified volume flow rate of outdoor air (State 0) to meet air quality requirements. The mixed air stream (State 1) is cooled to the dewpoint temperature (T1A and dehumidified by the cooling system to a relative humidity of 100% (State 1B). Finally, the air is reheated by a electric resistance coil heating system to the supply air conditions (State 2). Using the psychrometric chart, determine the following given the conditions below. --Given Values--
T3 (F) = 76
T3wb (F) = 63
T0 (F) = 94
Phi0 () = 0.53
AV0 (cfm) = 501
QT (Btu/hr) = 59000
T1B (F) = 47
T3-T2 (F) = 15
a) Determine the humidity ratio at State 3.
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b) Determine the specific enthalpy (Btu/lb) at State 3.
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c) Determine the humidity ratio at State 2
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d) Determine the temperature (F) at State 2.
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e) Determine the specific enthalpy (Btu/lb) at State 2.
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f) Determine the specific enthalpy (Btu/lb) at State x.
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g) Determine the sensible heat factor for the space.
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h) Determine QS, the sensible heat transfer (Btu/h) for the space.
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i) Determine the mass flow rate (lb/h) at State 2.
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j) Determine the specific volume of the air (ft^3/lba) at State 2.
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k) Determine the volumetric flow rate (cfm) at State 2.
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l) Determine the specific volume of the air (ft^3/lba) at State 0.
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m) Determine the mass flow rate (lb/h) at State 0
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n) Determine the fraction (%) of outdoor air.
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o) Determine the humidity ratio at State 0.
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p) Determine the specific enthalpy (Btu/lb) at State 0.
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q) Determine the specific enthalpy (Btu/lb) at State 1.
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r) Determine the humidity ratio at State 1.
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s) Determine the temperature (F) at State 1.
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t) Determine the dew point temperature (F) for State 1.
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u) Determine the specific enthalpy (Btu/lb) at State 1B.
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v) Determine QC, the load (Btu/h) for the cooling system
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w) Determine QH, the load (Btu/h) for the reheat system.
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