HVAC means Heating, Ventilation and Air Conditioning is use of different technologies to control the room, building humidity, temperature, air quality , air pressure in a closed area. its goal to provide thermal comfort and indoor air quality for human and materials. there are few standards we have to follow while designing HVAC ,
for pipe : ASME the american scoeity of mechnical engineers .
design: ASHARE American society of heating refrigerating and air conditioning engineers .
duct : SMACNA sheet metal and air conditioning contractors national association .
the accepatable human confort levele is generally 22- 27 ‘c and relative humidity of 40 % – 60 %. for materilas it depends on the reuirement and industry; food, pahrmacetical.
Application of HVAC
- High rise building
- commercial complex
- hotels
- industrial operation
- hospital area
- pharmaceuticals
- food industry
- car parking area
External Heat
Glass and window area (GLF):
Glass load factors may be found in according to window orientation , type of glass, type of interior shading, outdoor design temperature and glass are. q=(GLF).A
Doors Ud = design heat transfer coefficient for door from; A- area of door calculated from building plans and CLTD – cooling load temperature difference q.Ud = A(CLTD)
Uw= de Above grade exterior walls signs heat transfer coefficient for exterior wall from A= area of exterior wall calculated from buildings plans and CLTD – cooling load temperature difference q.Uw= A(CLTD)
internal Heat
People
Qsensible = N (Sensible heat Gain )CLF
Q latent = N (Latent heat gain)
N = number of people in space , from best available source, sensible and latent heat gain from occupancy
CLF =cooling load factor byn hour occupancy CLF 1.0 with high density or 24 hr occupancy and if cooling off at night or during weekends
Lights and appliances
Qif = 3.41WfulFsa(CLF)
W= watts input from electrical plans or lightning fixture data
Ful = lightning use factor as appropriate
Fsa= Special allowance factor , as approporate
CLF =cooling load factor by hour of occupancy
CLF
Air distribution system
Duct types
Rectangular | Circular | Oval
duct material
Galvanized steel | Aluminum | stainless steel | carbon steel | copper
Duct hanger spacing
if we don’t follow proper duct hanging space noise will generate from duct vibration generation in the duct and duct life reduce