Answer Happy

(4-8) Five persons occupy an office which have overall dimensions of 6 x 5 x 3 m. The air change per hour due to infiltration is estimated to be 1.5. If the inside and the outside air temperatures are 20 °C and 5 °C, respectively. Calculate the heat load due to infiltration. (4-9) A classroom is maintained at 20 °C db and 45% RH and is occupied by 50- students. Find the heat load due to ventilation if the outside fresh air is available at 5 °C and 60% RH. (4-10) The sale section of a department store is occupied by a total of 30- persons. The heat gain through walls, doors, etc. is estimated to be 15 kW. The lighting load totals 3 kW. The inside design conditions are 25.6 °C db and 50% RH. The outside conditions are 35 °C db and 36% RH. Calculate the followings: (a) Cooling load of the ventilation air. (b) Total sensible and latent heat loads of the sale section. (c) Sensible heat ratio. Assume (CLF)oc. = 0.88 and (CLF)t = 0.76. (4-11) The cooling load data for an auditorium are as follows: Occupancy 1,500-person Inside design conditions 24 °C db and 50% RH Outside design conditions 34 °C db and 26°C wb Supplyair per person 50 m/h Supply conditions 10 °C and 90% RH Calculate the capacity of the cooling coil and the cooling load of the auditorium. Take (CLF).c. = 1.0 (4-12) A room is supplied with 15 m/h of ventilation air. The outside air contains 0.04 ppm of CO2. The carbon dioxide generation inside the room is 0.0 m/h. Find the amount of CO2 that exists inside the room in mg/m' and in ppm. (4-13) Carbon monoxide (CO) is generated inside a space at a rate of 1 kg/h. The maximum allowed rate of CO in the space is 0.3 x 10-kg/h. If the outside air con- tains no carbon monoxide, calculate the ventilation air flow rate needed and the number of air changes per day if the space dimensions are 5 x 3 x 3 m. (4-14) An office measures 4 x 6 x 4 m and is occupied by 20-persons, each generates 0.023 m/h of carbon dioxide. The maximum concentration of carbon dioxide is 1 liter CO2/m of air. The outside air contains 3 x 10 m CO2 per m of air. Calculate ventilation air required and number of air changes per hour.