It has come to your attention that your client has just finalized the design of their new building which consists of a general office and a department store. The amount of outside air that must be brought into the air-conditioning unit for ventilation has also been specified as follows: General office Department store Size (L x W x H) 50 ft x 25 ft x 10 ft 500 ft x 40 ft x 10 ft Specified outdoor air 80 cfm 4,000 cfm Est. occupant density Refer ASHRAE Std. 62.1 Refer ASHRAE Std. 62.1 As the HVAC specialist, you are required to check on the specifications provided based on ASHRAE Standard 62.1. An extract of the standard is provided below for your reference. Table 6-1, ASHRAF Standard 12.1.2010) Default Values People Outdoor Air Rate Rp Area Outdoor Air Rate RA Combined Outdoor Air Rate (see Note 5) Occupant Density (see Note 4) #1000 fr? or #/100 m2 CFM person Lly person CFM/12 L/sm? Notes Air Class CFM.person L/s person 06 0.3 Occupancy Category Common comdir Retail Sales (except as below) Mall common arcas Tarbershop Beauty and nail salons Pet shops (animal areas) Supermarket Coin-operated Laundries 3.8 75 7.5 7.5 20 7.5 7.3 7.5 0.12 0.06 16 0.12 0.18 0.06 0.12 (1.6 0.3 CIR 0.6 0.9 10 3.8 3.8 3.8 IS 10 35 25 10 8 20 16 9 TO 25 26 1$ 14 2 1 2 2 4.6 3.0 124 12.8 7.6 7.0 1 0.6 50 10 7 11 Uffice Buildings Breakrooms Main entry lobbies Occupiable storage rooms for dry materials Office space Reception ares Telephone data entry 2.5 2.5 2.5 2.5 2.5 25 0.12 0.06 0.06 0.06 0.06 0.06 0.6 0.3 0.3 0.3 0.3 0.3 2 5 30 60 35 17 3.5 5.5 17.5 8.5 3.5 3.0 a. Determine the amount of outdoor air required based on the ventilation rate procedures in ASHRAE Standard 62.1. b. Analyze and comment on whether the specified outdoor air required (in the table above) can be accepted in this design. c. Supposed the recommended quantities of total air and outside air is used, determine the corresponding percentage of outdoor air to be supplied. Note that the recommended quantities of total air should typically ensure 6 ACH, while the outside air is as stipulated in ASHRAE Standard 62.1. d. Comment on how you may control the percentage of outdoor air supplied. e. The client has called in to inform that he expects no recirculation air in this HVAC system. Provide your recommendation with regards to this matter. It has come to your attention that your client has just finalized the design of their new building which consists of a general office and a department store. The amount of outside air that must be brought into the air-conditioning unit for ventilation has also been specified as follows: General office Department store Size (L x W x H) 50 ft x 25 ft x 10 ft 500 ft x 40 ft x 10 ft Specified outdoor air 80 cfm 4,000 cfm Est. occupant density Refer ASHRAE Std. 62.1 Refer ASHRAE Std. 62.1 As the HVAC specialist, you are required to check on the specifications provided based on ASHRAE Standard 62.1. An extract of the standard is provided below for your reference. Table 6-1, ASHRAF Standard 12.1.2010) Default Values People Outdoor Air Rate Rp Area Outdoor Air Rate RA Combined Outdoor Air Rate (see Note 5) Occupant Density (see Note 4) #1000 fr? or #/100 m2 CFM person Lly person CFM/12 L/sm? Notes Air Class CFM.person L/s person 06 0.3 Occupancy Category Common comdir Retail Sales (except as below) Mall common arcas Tarbershop Beauty and nail salons Pet shops (animal areas) Supermarket Coin-operated Laundries 3.8 75 7.5 7.5 20 7.5 7.3 7.5 0.12 0.06 16 0.12 0.18 0.06 0.12 (1.6 0.3 CIR 0.6 0.9 10 3.8 3.8 3.8 IS 10 35 25 10 8 20 16 9 TO 25 26 1$ 14 2 1 2 2 4.6 3.0 124 12.8 7.6 7.0 1 0.6 50 10 7 11 Uffice Buildings Breakrooms Main entry lobbies Occupiable storage rooms for dry materials Office space Reception ares Telephone data entry 2.5 2.5 2.5 2.5 2.5 25 0.12 0.06 0.06 0.06 0.06 0.06 0.6 0.3 0.3 0.3 0.3 0.3 2 5 30 60 35 17 3.5 5.5 17.5 8.5 3.5 3.0 a. Determine the amount of outdoor air required based on the ventilation rate procedures in ASHRAE Standard 62.1. b. Analyze and comment on whether the specified outdoor air required (in the table above) can be accepted in this design. c. Supposed the recommended quantities of total air and outside air is used, determine the corresponding percentage of outdoor air to be supplied. Note that the recommended quantities of total air should typically ensure 6 ACH, while the outside air is as stipulated in ASHRAE Standard 62.1. d. Comment on how you may control the percentage of outdoor air supplied. e. The client has called in to inform that he expects no recirculation air in this HVAC system. Provide your recommendation with regards to this matter
