3 Description of the product
3.1
Cascade configuration
In many situations it is advantageous to spread the total required heat out
put over several boilers. This can be made possible by means of a "cas
cade configuration". In a cascade configuration, heating boilers are con
nected hydraulically. If the heat demand increases or decreases, boilers
are switched on or off respectively. It is then important to determine the
ideal number of boilers for the cascade. The following factors need to be
taken into account when deciding on the number of boilers:
Investment:
When boilers are split up, the investment costs (boiler cost including in
stallation, fittings, pipe work, pumps and control equipment) can work
out lower or higher. However, this depends to a large extent on the sit
uation.
Reliability:
Reliability increases with the number of boilers. Research has shown
that reliability is already optimum for systems with four boilers in a cas
cade.
Efficiency:
There is no appreciable difference in terms of efficiency between several
small or one or two larger boilers.
Maintenance and faults:
There is a greater overall risk of faults in a system with several boilers. A
larger group of engineers can service and maintain smaller boilers.
Arrangement:
The compact units and therefore compact configuration means that you
have more flexibility for potential boiler locations.
Adjustment:
When using several boilers and modulating control, the heat output of
fered is virtually equal to the heat output requested.
Important
A number of the points mentioned are dependent on the situa
tion and so consideration as to which solution is the best will
need to be given on a project-by-project basis.
3.2
Hydraulic isolation: low-loss header
Practical experience has shown that it is beneficial to create hydraulic iso
lation between the boiler circuit and the system circuit using a low-loss
header. This means that a widely varying volume flow on the system side
hardly influences the volume flow on the boiler side at all. This also applies
in reverse: a widely varying volume flow on the boiler side hardly influen
ces the volume flow on the system side at all. Controlling several different
groups hydraulically is therefore significantly easier as they do not, or
barely, influence each other. This creates better overall operating condi
tions for the system.
3.3
De Dietrich cascade systems
In order to make it as simple as possible to create a cascade configura
tion, De Dietrich has included complete cascade systems in the range for
some years. The compact design of the boilers, combined with the smart
gas and water connection technology (no brazing) of the cascade system,
makes it possible to install a high heat output system in a small area.
For example, eight MCA 160 boilers can be installed in an area of 4.4 m²
(including low-loss header) to provide close to 1200 kW.
3 Description of the product
6
MCA
7680446 - v.01 - 14082017
