Mark NFRA AQUA ECO Livret Technique page 6

4. Determine the upper temperature:
T + T
wi wu
k = ————— – T
2
65 + 50
k = ————— – 18 = 39 Kelvin
2
This value can be used to look up the heat capacity of the panel in the table (heat delivery
table) [6] (type 1,2,3 and 4). This is the value Q
(T=1) Q = 132 W/m (heat output table) [6]
pp
5. Determine the heat delivery for a single length:
q = L x Q
B pp
q = 42 x 132 = 5544 W/section
6. Determine the temperature variation of the water:
∆T = T – T
wi wu
∆T = 65 – 50 = 15 K
7. Determine the mass flow of the liquid in one panel length:
m = (q/∆T ) x 0.86
5544
m = ———— x 0,86 = 318 kg/h
15
8. Determine the mass flow per pipe:
m = m / n
pb
1 section consisting of a Type 1 panel. [2]
Flow may take place through 4 pipes or 2 pipes. The mass flow must be calculated for these
two situations in order to connect the panel on the water side.
m =
pb
Check the minimum mass flow using the appropriate table [7] (68 kg/h). The calculated value
9.
must be higher in order to achieve turbulent flow through the pipes. This then gives the
correct number of distributors [2].
6
omg
318 / 4 = 79,5 kg/h (B)
318 / 2 = 159 kg/h (A)
.
pp