Heatcraft Refrigeration Products H-ENGM0408, H-ENGM0806 manual = Current Amperes

IL2 =

IL3 =

IL1 =

I2 + I2 + ( I1 X I2 ) 3 1

I2 + I2 + ( I2 X I3 ) 2 3

I2 + I2 + ( I1 X I3 ) 3 1

If the phase are unbalanced, each of the phase will differ from the others:

FORMULAE:

Product

Sensible Heat in BTU/hr. = lbs/hr. x Sp. Ht. x T

Latent Heat in BTU/hr.= lbs/hr. x Lt. Ht. in Btu/lb.

Heat of Resp. in BTU/hr . = lbs x Heat or Respiration in BTU/lb./hr.

All conversion factors used in standard calculations must be corrected for other than standard properties

Nomenclature

Q = Heat Flow in BTU/hr.

T = Temperature in ºF. ( T = temp. diff.) A = Area in Sq. Ft.

U = Coef. of Heat Transfer in BTU/hr./Sq.Ft./ºF. H = Total heat of air at wet bulb temp. BTU/lb.

H = Enthalpy difference between entering & leaving air SH = Specific humidity in grains of moisture/lb. of dry air

( SH = Specific humidity difference for entering and leaving air)

CFM = Cu. Ft./min. GPM = Gal/min.

3 Phase Delta Loads

3 0 Balanced Loads = P1 + P2 + P3

Total Line Current = Total Power (Balanced Load)

= BTU/hr.

Heat Transmission

Q Total = U x A Surface x T

Table 30.

Conversion Factors (constant)

Water
500 = 8.33 lbs./gal. x 60 min,		– (Converts GPM to lbs./hr.)
Air
4.5 = 60 min		– (Converts CFM to lbs./hr.)
	13.35 Cu. Ft./lb.
1.08 = 4.5 x 0.241 BTU/lb./ºF.		– (lbs./hr. x Sp. Ht. of Air)
0.68 = 4.5 x 1054.3 BTU/lb.
	7000 gr/lb.	– (4.5 combined with heat
		of vaporization of water
		at 70ºF. and grains per
		pound of water)

Water Heating, Cooling & Heat Reclaim Coils, Water Chillers,

Condensers, etc.
Q = 500 x GPM x T		= BTU/hr.
T = Q
	500 x GPM

For brines, Q = 500 x GPM x T x (Sp. Ht. x Sp. Gr. of Brine)

Properties of Water at 39.2 ºF.

Density of Water	= 62.4 lbs./Cu. Ft.
Specific Heat of Water	= 1 BTU/lb./ºF.
Latent Heat of	= 970 BTU/lb. at 212ºF. & Atm.
Vaporization	= 1054.3 BTU/lb. at 70ºF.
Specific Heat of Ice	= 0.5 BTU/lb./ºF.
Latent Heat of Fusion	= 144 BTU/lb.
1 Gallon of Water	= 8.33 lbs.
1 Pound of Water	= 7000 Grains

Air Coils

Q Sensible = 1.08 x CFM x T		= BTU/hr.
Q Latent = 0.68 x CFM x	SH	= BTU/hr.
Q Total = 4.5 x CFM x H	= BTU/hr.
lb./hr. Condensate		= 4.5 x CFM x SH Grains
		7000 grains/lb
SHR Sensible Heat Ratio	= Q Sensible
		Q Total

Table 31.

Single Phase Loads

Ohm’s Law for direct current

		E	E
		R	R	W
		I2 X R
				E
	E X I	W	I	W
				R
	E2	R	E	I X R
	W
		E		W
		I		I
		W	W X R
		I2
W = Watts
I	= Current (Amperes)
E = Electromotive Force (Volts)
R = Resistance (Ohms)

To obtain any values in the center circle, for Direct or Alternating Current, perform the operation indicated in one segment of the adjacent outer circle.

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