26
So: The heat required to heat 500 litres of water in a tank from 40°C to
70°C is 62,805 kJ (= 62,805 kWs) (disregarding any losses or heat drawn
within the system). That corresponds to approx. 17.4 kWh.
Assuming that the ambiente a4 H
2
O has an average output of approx. 5.4
kW it will take about 3.2 hours to heat up the entire tank (500 L). This
calculation is based on heating up the entire volume in the tank uniformly.
In an efficiently designed heating system the hot water is stored in layers
in the buffer tank, e.g. in a stratified storage system. That way, hot water is
available after heating up for only a short time and heat is available for use
shortly after circulation starts in the ambiente a4 H
2
O. Only surplus energy
not needed for heating is then stored in the buffer tank.
On very cold winter days an ambiente a4 H
2
O may sometimes be in oper-
ation for about 12 hours. The quantity of heat thus produced then corre-
sponds theoretically to 65 kWh. That quantity of heat would heat approx.
1,900 litres (from 40°C to 70°C). As a rule, though, heat is always drawn
off in such a situation and so overheating of the buffer tank (> 90°C) will
not occur.
This calculation does not take account of material heating occurring in the
buffer tank and pipes or radiation losses from the system components, etc.
Such factors extend the buffer tank heating-up time in practice.
2.9.7 LOAD UNIT (HEAT CHARGER) IN THE ambiente
a4 H
2
O STOVES
As a general rule, the ambiente a4 H
2
O may only be operated with a load
unit (heat charger). In operation, the supply flow temperature should be at
least 65°C and the return temperature at least 62°C. In order to ensure that
these temperatures are guaranteed, a circulation pump / load unit (heat
charger) are to be installed in such a way that they will only start-up when
the temperature has reached 62°C. To reduce the danger of overshooting
the dew point, a “controllable” load unit (heat charger) is generally to be
installed. This involves capturing the control variable, which corresponds to
the effective return temperature at the entry to the water heat exchanger,
and adjusting it to the desired value.
We
recommend
the use of the load unit (heat charger) type LTC 141 from
the company ESBE, which is optionally available, or a comparable load unit
(heat charger). The use of other solutions (e.g. a four-way mixer) has not
proved successful in practice and is, therefore,
not
recommended.
We cannot accept any liability nor provide guarantee cover for a
ny mal-
functions
(sooting, deposits, etc.) or
corrosion damage
to the water heat
exchanger or chimney etc. that are due to a missing or non-effective load
unit (heat charger).
