Design Guide HEV-HEH SEriES Heat Controller
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Engineering Design Guide HEV/H SERIES Heat Controller, LLC
Reference Calculations
BTUH= BTU( British Thermal Unit) per hour
CFM= air ow, cubic feet/minute
COP= coef cient of performance = BTUH output/BTUH input
DB= dry bulb temperature (°F)
EAT= entering air temperature, Fahrenheit (dry bulb/wet bulb)
EER= energy ef ciency ratio = BTUH output/Watt input
EPT= external pipe thread
ESP= external static pressure (inches w.g.)
EWT= entering water temperature
GPM= water ow in U.S. gallons/minute
HE= total heat of extraction, BTUH
HC= air heating capacity, BTUH
HR= total heat of rejection, BTUH
HWC= hot water generator (desuperheater) capacity, Mbtuh
IPT= internal pipe thread
KW= total power unit input, kilowatts
LAT= leaving air temperature, °F
LC= latent cooling capacity, BTUH
LWT= leaving water temperature, °F
MBTUH= 1000 BTU per hour
S/T= sensible to total cooling ratio
SC= sensible cooling capacity, BTUH
TC= total cooling capacity, BTUH
WB= wet bulb temperature (°F)
WPD= waterside pressure drop (psi & ft. of hd.)
Conversion Table - to convert inch-pound (English) to SI (Metric)
Legend and Glossary of Abbreviations
LWT = EWT -
HE
GPM x 500
LAT = EAT +
HC
CFM x1.08
LWT = EWT +
HR
GPM x 500
LAT (DB) = EAT (DB) -
SC
CFM x1.08
LC = TC - SC
S/T =
SC
TC
Heating
Cooling
Air Flow Water Flow Ext Static Pressure Water Pressure Drop
Airflow (L/s) = CFM x 0.472 Water Flow (L/s) = gpm x 0.0631 ESP (Pa) = ESP (in of wg) x 249 PD (kPa) = PD (ft of hd) x 2.99
Hot Water Generator capacities (HWC) are based on potable water ow rate of 0.4 gpm per nominal equipment ton and 90°F
entering potable water temperature.
Piping End
Left Return Air Right Return Air
UPFLOW
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