PSYCHROMETRIC CHART FOR HVAC ANALYSIS · 2019. 9. 17. · PSYCHROMETRIC CHART FOR HVAC ANALYSIS...
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-10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 DRY BULB TEMPERATURE - °F 0 5 10 15 20 25 30 35 40 45 50 55 55 60 60 ENTHALPY - BTU PER POUND OF DRY AIR 0 5 10 15 20 25 30 35 40 45 50 ENTHALPY - BTU PER POUND OF DRY AIR .1 .2 .3 .4 .5 .6 .7 .8 .9 1 1.1 1.2 1.3 VAPOR PRESSURE - INCHES OF MERCURY 0 10 20 25 30 35 40 45 50 55 60 65 70 75 80 85 DEW POINT TEMPERATURE - °F 1.00 0.95 0.90 0.85 0.80 0.75 0.70 0.65 0.60 0.55 0.50 0.45 0.40 0.35 0.30 0.25 0.20 SENSIBLE HEAT RATIO = Qs / Qt SENSIBLE HEAT RATIO = Qs / Qt 10 40 50 60 70 80 90 120 130 140 150 170 200 15% 25% 2% 4% 6% 8% RELATIVE HUMIDITY 10% RELATIVE HUMIDITY 20% 30% 40% 50% 60% 70% 80% 90% -5 0 0 5 5 10 10 15 15 20 20 25 25 30 30 35 35 40 40 45 45 50 50 55 55 60 60 65 65 70 70 75 75 80 80 85 90 12.0 13.0 14.0 VOLUME- CU.FT. PER LB. DRY AIR 15.0 HUMIDITY RATIO - GRAINS OF MOISTURE PER POUND OF DRY AIR 85 WET BULB TEMPERATURE - °F 20 30 100 110 160 180 190 PSYCHROMETRIC CHART FOR HVAC ANALYSIS Air–Conditioning Formulas and Conversion Factors Atmospheric pressure = 29.921" Hg. at sea level 1 BTU = Amount of heat required to raise (or lower) the temperature of one pound of water 1°F 1 ton of refrigeration = 12,000 Btu/hr = 200 Btu/min 1 watt = 3.414 Btu/hr 1 horsepower = 2545.6 Btu/hr 1 ft (head) = 0.433 psi (at 62°F) 1 boiler horsepower = 33,475 Btu/hr Air changes per hour (N) in a space N = (60 x CFM) / space ft 3 CFM = airflow rate (ft 3 /min) Water quantity (GPM) required for heating and cooling GPM = q / (500 x Δt) q = load in Btu/hr t = water temperature Chiller capacity (Tons) Tons = (GPM x Δt) / 24 GPM = gallons per minute of chilled water t = water temperature Pump hp = x specific gravity Fan hp = x Total cooling (Btu/hr) = CFM x 4.5 x Δh Sensible cooling (Btu/hr) = CFM x 1.085 x Δt Latent cooling (Btu/hr) = CFM x 4840 x Δw CFM = airflow rate (ft 3 /min) h = enthalpy (Btu/lb) t = dry bulb air temperature (°F) w = humidity ratio (lb water / lb dry air) Fan Laws CFM 2 = CFM 1 x (RPM 2 / RPM 1 ) SP 2 = SP 1 x (RPM 2 / RPM 1 ) 2 HP 2 = HP 1 x (RPM 2 / RPM 1 ) 3 1 = initial; 2 = desired GPM x ft head 3960 x efficiency CFM x static pressure (in. W.G.) 6356 x efficiency density of air density of standard air
Transcript of PSYCHROMETRIC CHART FOR HVAC ANALYSIS · 2019. 9. 17. · PSYCHROMETRIC CHART FOR HVAC ANALYSIS...
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PSYCHROMETRIC CHART FOR HVAC ANALYSISAir–Conditioning Formulas and Conversion FactorsAtmospheric pressure = 29.921" Hg. at sea level
1 BTU = Amount of heat required to raise (or lower) the temperature of one pound of water 1°F
1 ton of refrigeration = 12,000 Btu/hr = 200 Btu/min
1 watt = 3.414 Btu/hr
1 horsepower = 2545.6 Btu/hr
1 ft (head) = 0.433 psi (at 62°F)
1 boiler horsepower = 33,475 Btu/hr
Air changes per hour (N) in a space N = (60 x CFM) / space ft 3
CFM = air�ow rate (ft 3/min)
Water quantity (GPM) required for heating and cooling GPM = q / (500 x Δt)q = load in Btu/hrt = water temperature
Chiller capacity (Tons) Tons = (GPM x Δt) / 24GPM = gallons per minute of chilled water t = water temperature
Pump hp = x speci�c gravity
Fan hp = x
Total cooling (Btu/hr) = CFM x 4.5 x Δh
Sensible cooling (Btu/hr) = CFM x 1.085 x Δt
Latent cooling (Btu/hr) = CFM x 4840 x Δw
CFM = air�ow rate (ft 3/min)h = enthalpy (Btu/lb)t = dry bulb air temperature (°F)w = humidity ratio (lb water / lb dry air)
Fan LawsCFM2 = CFM1 x (RPM2 / RPM1)SP2 = SP1 x (RPM2 / RPM1)
2
HP2 = HP1 x (RPM2 / RPM1)3
1 = initial; 2 = desired
GPM x ft head3960 x e�ciency
CFM x static pressure (in. W.G.)6356 x e�ciency
density of airdensity of standard air
