h w
enthalpy of air-water mixture at bulk water temperature, J /kg dry air or
Btu/lb dry air
H s
gross solar radiation, kcal/d m
2
K
surface heat coefficient or heat transfer coefficient at the pond surface,
Kcal/d - m
2 -
C
K
mass transfer coefficient, lb water/hr ft
2
KaV/L tower characteristic
q
heat dissipated, Kcal/d
q a
long-wave solar radiation, Kcal/day-m
2 or 400 Btu/day-ft
2
q c
conductive-convective heat loss, Kcal/day-m
2 or 400 Btu/day-ft
2
q d
Discharge of a heated effluent, Kcal/day-m
2 or 400 Btu/day-ft
2
q e
evaporative heat loss, Kcal/day-m
2 or 400 Btu/day-ft
2
q r j
heat flux, Kcal/d-m
2
q s
short-wave solar radiation, Kcal/day-m
2 or 400 Btu/day-ft
2
q t
net heat flux across the air-water interface, Kcal/day-m
2 or 400 Btu/day-ft
2
q a r
reflected portion of q a , Kcal/day-m
2 or 400 Btu/day-ft
2
q b r
long-wave black radiation from water surface, Kcal/day-m
2 or 400 Btu/
day-ft
2
q s r
reflected portion of q s , Kcal/day-m
2 or 400 Btu/day-ft
2
Q
volumetric flow rate, m
3 /d
T
bulk water temperature, F or
C
T avg
average temperature ¼ (T d + T s )/2,
C
T d
dew point temperature,
C
T s
surface temperature of the pond,
C
T x
the boundary condition of T at X ¼ X
T o
the boundary condition of T at X ¼ 0
T s m
completely mixed cooling pond’s actual surface temperature,
C
T s u
completely unmixed cooling pond’s actual surface temperature,
C
T1
hot water temperature,
F or
C
T2
cold water temperature,
F or
C
u
average flow velocity, m/d
U
wind speed, km/hr
V
active cooling volume/plan area/, m or ft
X
distance from pond entry, m
α
mixing coefficient
α m
α evaluated for the completely mixed cooling pond
α u
α evaluated for the completely unmixed cooling pond
ρ
density of water, 1.0 g/cm
3
δT/δX
longitudinal temperature gradient,
C/m
5 Cooling and Reuse of Thermal Discharges
197
enthalpy of air-water mixture at bulk water temperature, J /kg dry air or
Btu/lb dry air
H s
gross solar radiation, kcal/d m
2
K
surface heat coefficient or heat transfer coefficient at the pond surface,
Kcal/d - m
2 -
C
K
mass transfer coefficient, lb water/hr ft
2
KaV/L tower characteristic
q
heat dissipated, Kcal/d
q a
long-wave solar radiation, Kcal/day-m
2 or 400 Btu/day-ft
2
q c
conductive-convective heat loss, Kcal/day-m
2 or 400 Btu/day-ft
2
q d
Discharge of a heated effluent, Kcal/day-m
2 or 400 Btu/day-ft
2
q e
evaporative heat loss, Kcal/day-m
2 or 400 Btu/day-ft
2
q r j
heat flux, Kcal/d-m
2
q s
short-wave solar radiation, Kcal/day-m
2 or 400 Btu/day-ft
2
q t
net heat flux across the air-water interface, Kcal/day-m
2 or 400 Btu/day-ft
2
q a r
reflected portion of q a , Kcal/day-m
2 or 400 Btu/day-ft
2
q b r
long-wave black radiation from water surface, Kcal/day-m
2 or 400 Btu/
day-ft
2
q s r
reflected portion of q s , Kcal/day-m
2 or 400 Btu/day-ft
2
Q
volumetric flow rate, m
3 /d
T
bulk water temperature, F or
C
T avg
average temperature ¼ (T d + T s )/2,
C
T d
dew point temperature,
C
T s
surface temperature of the pond,
C
T x
the boundary condition of T at X ¼ X
T o
the boundary condition of T at X ¼ 0
T s m
completely mixed cooling pond’s actual surface temperature,
C
T s u
completely unmixed cooling pond’s actual surface temperature,
C
T1
hot water temperature,
F or
C
T2
cold water temperature,
F or
C
u
average flow velocity, m/d
U
wind speed, km/hr
V
active cooling volume/plan area/, m or ft
X
distance from pond entry, m
α
mixing coefficient
α m
α evaluated for the completely mixed cooling pond
α u
α evaluated for the completely unmixed cooling pond
ρ
density of water, 1.0 g/cm
3
δT/δX
longitudinal temperature gradient,
C/m
5 Cooling and Reuse of Thermal Discharges
197