Answer Happy

Section B Choose ANY THREE questions from this section. Bl. An office in the interior zone of a building is served by a single zone constant air volume air conditioning system. The sensible and total space cooling loads. are 45 kW and 56.5 kW respectively. Outdoor air supply is ducted to the mixing plenum at the air-handling unit (AHU) to mix with the recirculating air. The fresh air intake rate is 8 l/s per person. The following data is available: Summer outdoor design temperature: 33 °C dry bulb 28 °C wet bulb Indoor design conditions: 25 °C dry bulb 50% RH Off-coil relative humidity: 90% Design occupancy: 80 persons Supply and return system heat gains are neglected. (a) Determine the dry bulb temperature and specific enthalpy of the supply air to the office. (5 Marks) (b) Determine the volume flow rate of the supply air. (3 Marks) (c) Determine the on-coil dry bulb temperature and specific enthalpy. (6 Marks) (d) Determine the cooling coil's load. (2 Marks) (e) Suggest TWO methods to reduce the ventilation/refrigeration load of the air conditioning system. (4 Marks) Draw the air conditioning cycle on the psychometric chart provided.
CIBSE PSYCHROMETRIC CHART SEK PEDRO ADD 63 14 BASED ON A BAROMETR PRESSURE OF 101.325 P SPECIFIC ENTRALPY N 6 SPECIFIC VOLUME WET BULSTEMPERATURE (INC) % DY-BULOTERATUR SPEorie ENTHALPYK 130 US PERCENTAGE SATURATION 40 D 0:050 O Dan ODST 0221 DOM -0.036 0:003 cm 201 60 2010 s 6317 2016 2018 0.014 0:00 0011 oms 0010 CON GOOF acce 0.00 BOX B00 LOO 6.001 600 MOISTURE CONTENT ma n ce 199 BEVERLY 041 12 621