Panasonic Aquarea WH-ADC0309J3E5 Planning And Installation Manual page 114

Planning
Model-specific limit values for the integrated expansion vessel
Expansion vessel volume
Initial pressure
Total water quantity in the heating system (max.)
Static height
Pressure stage safety valve (max.)
In case the total quantity of water is greater than 150 or 200 litres, or greater static heights are
required, it is necessary to maintain the pressure by means of an expansion vessel to be installed
on site. Generally, pay attention to the pressure stage of the safety valve. This is given in the
technical data and is maximum 3 bar.
The following criteria must be taken into consideration when designing the necessary expansion
vessel nominal volume V
Nominal volume
Expansion volume
System volume
Water reserve
Maximum temperature
Final pressure of the safety valve
Initial pressure of expansion vessel
5
V
N
114
.
N
p + 1
e
= (V + V )
e V
p – p
e 0
1. The expansion volume V
temperature is obtained from the coefficient of expansion of water according to the
following table:
T (°C) 40
max
n (%) 0.93
Percentage expansion of water:
n
V = V
e A
100
2. The volume of the water reserve V
follows:
V = 0.2 × V (for a nominal volume V
V N
V = 0.005 × V (for a nominal volume V
V A
3. The final pressure of the safety valve p
safety valve minus a tolerance of 0.5 bar:
p = Safety valve response pressure – 0.5 bar
e
4. Select the initial pressure p
system plus a supplement factor of max. 0.5 bar. 10 metres static height corresponds
to 1 bar. Adjust the initial pressure of the Aquarea expansion vessel, if necessary.
l
bar
l
m
bar
V (nominal volume of the expansion vessel)
N
V (expansion volume of the expansion vessel)
e
V (total volume of the heating system)
A
V (volume of the water reserve)
V
T (highest temperature in the system e.g. 60 °C)
max
p (depends on the safety valve, max. 2.5 bar)
e
p (initial pressure 1 bar)
0
is obtained from the system volume, and the maximum
e
50 60
1.29 1.71
can be calculated in a simplified manner as
V
< 15 litres) or
N
> 15 litres, where V
N
is obtained from the response pressure of the
e
such that it corresponds to the static height of the heating
0
Aquarea air-to-water heat pumps - Planning and installation manual - 02/2022
WH-MDC05J3E5 All other models
WH-MDC07J3E5
WH-MDC09J3E5
6
1
150
7
3
70 80 90
2.22 2.81 3.47
≥ 3 litres)
V
10
1
200
7
3
100
4.21