4 Capacity and selection
data
TCGB0070 rev.3 - 04/2012
74
-
Calculation of
T
:
The domestic hot water tank’s temperature should be estimated. It is referred to the accumulated water
temperature inside the tank, before the use. Habitually the temperature’s rank is between 45ºC - 65ºC. In
the example below, it has been taken 45ºC.
-
Calculation of
T
i
:
The inlet cold water temperature is the temperature of the water that is filling the tank to accumulate it.
The cold water rank’s temperature is 10ºC - 15ºC. To calculate an approximate water demand its has been
used 12ºC.
-
Example:
D
i
(T)= 120 x (60-12
/ 45-12) =
174.6 litres/day
174.6 x 2(*) =
349.2
litres/day
hot water approximate demand
N O T E
(*): In the case that the installation would be in a detached house, it could be recommended to multiply the cal
-
culated consumption per two. This is donne to ensure the hot water supply with guarantees. In the case of mul
-
tifamily installation, it is not necessary to increase the prevision of hot water demand due to the existence of a
less simultaneity factor.
Therefore, it should be selected a 200 litres tank, otherwise, it is recommended the 300 litres tank when the YUTAKI S
system is RAS-4HVRNME-AF + RWM-4.0FSN3E or upper combination power, in order to guarantee a longer hot water
supply and a better operation. In the case that the conditions of demand and the YUTAKI S system would be lower than
those specifications it could be selected between 200 litres and 300 litres tank depending on the demand conditions.
Below, it is shown a table with the Domestic Hot Water Tank selection recommended by HITACHI for the different existing
combinations:
YUTAKI S system
Domestic Hot Water Tank
RAS-2HVRN2
+RWM-2.0(H)FSN3E
DHWT-200(E/S)-2.5H1E
DHWT-300(E/S)-2.5H1E
RAS-3HVRNME-AF
+ RWM-3.0(H)FSN3E
RAS-4HVRNME-AF
+ RWM-4.0(H)FSN3E
DHWT-300(E/S)-2.5H1E
RAS-5HVRNME-AF
+ RWM-5.0(H)FSN3E
RAS-6HVRNME-AF
+ RWM-6.0(H)FSN3E
RAS-8HRNME-AF
+RWM-8.0(H)FSN3E
RAS-10HRNME-AF
+RWM-10.0(H)FSN3E
N O T E
• The YUTAKI S system is designed for combination with HITACHI Domestic Hot Water Tank. In case of another
tank is being used in combination with YUTAKI S system, HITACHI cannot guarantee neither good operation
for reliability of the system.
• This Domestic Hot Water Tank selection procedure is just orientated, be sure of consulting the local legislation
to ensure a good water demand value.
