Influence Of The Set Room Temperature On Efficiency; Influence Of The Sizing Of The Heat Exchanger On Efficiency; Influence Of Heat Transfer To The Outside Or Into Neighbouring Rooms; Temperature Monitoring - Bosch Src 100 Rf Installations- Und Bedienungsanleitung

6.4.4

Influence of the set room temperature on efficiency

The adaptive heating curve aims to supply heat according to demand.
The system always attempts to fulfil desires of the user. A high set room
temperature naturally requires a correspondingly higher flow
temperature. Depending on the design of the underfloor heating system
or the radiators, a room temperature that is 1 K higher causes the flow
temperature to rise by 1 K to 4 K or even more, for example, which can
lead to inefficient operation of the heat generator.
Conversely, a reduction in the set room temperature results in a
reduction in the flow temperature. This leads to more efficient operation
of the heat generator and also to lower heat losses.
Example: lowering the set room temperature
• Reduction from 21 °C to 20 °C
• This results in a reduction of the flow temperature by 2 K.
• This results in an increase in efficiency of 6 % (assuming an air-to-
water heat pump with an efficiency influence of 2-4 %/K).
• In addition, heat losses through the building envelope to the
environment are reduced.
It is a particular benefit in rooms such as bathrooms if the set room
temperature is not 21 °C all day, for example, but only in the morning and
evening. During the day, the temperature can be lowered to 20 °C, for
example. This is conveniently possible with the time program, which can
be set individually for each individual control in the Bosch HomeCom
Easy app.
6.4.5

Influence of the sizing of the heat exchanger on efficiency

In addition to the set room temperature, the sizing of radiators or the
underfloor heating system is a decisive factor for efficiency.
Large radiators and underfloor heating systems with a large surface area
and narrow installation spacing of the underfloor heating layer in the
floor tend to lead to low flow and return temperatures and therefore to a
higher efficiency of the heat generator. Small heat transfer surfaces lead
to higher flow and return temperatures and therefore to lower efficiency.
It is therefore a benefit if all rooms have as large a heat transfer surface
as possible (in relation to the required heating capacity). Particular
attention should be placed on bathrooms, as these rooms frequently
have a relatively limited area for installing underfloor heating or
radiators. In addition, these are usually the rooms with the highest set
room temperatures.
6.4.6 Influence of heat transfer to the outside or into
neighbouring rooms
The individual control system endeavours to regulate to the desired set
room temperature. Excessive uncontrolled heat transmission can have a
negative impact on comfort and efficiency.
The simplest example is an open window over a long period of time
(several hours). Heat is lost to the outside through the open window
(heat transmission to the outside) and the room temperature drops. The
system attempts to compensate for this heat loss and for the room
temperature falling below the set room temperature. For this purpose,
the heating water flow rate into the room affected is increased and, if
necessary, the flow temperature is also increased, which in turn has a
negative effect on the efficiency of the heat generator.
SRC 100 RF – 6721856014 (2024/11)
.
Q
= 20 °C
ϑ
RS
ϑ = 5 °C
A
Fig. 22 Example of heat transmission between outside and after-rooms
Outdoor temperature
ϑ
A
Set room temp.
ϑ
RS
Heat transmission
Another example is the open door between the bathroom and the
hallway. Heat flows from the bathroom (21 °C) into the hallway (17 °C)
through the open door. This causes the room temperature in the
bathroom to drop. The system attempts to compensate for this heat loss
and for the room temperature falling below the set room temperature,
with the negative consequences for efficiency described above. In this
case, it would be a benefit to keep the door closed or to equalise the set
room temperatures.
6.5

Temperature monitoring

This function monitors whether one or more rooms do not reach the set
room temperature over a longer period of time.
This may be the case, for example, if the valve or actuator of the
underfloor heating system is defective and therefore no heating water
flows through the underfloor heating system in the room affected. As a
result, the room is no longer supplied with sufficient heat and is
therefore not properly heated.
This monitoring function is intended for use in combination with heat
pumps and with the selected control type "Individual control". There are
two reasons for this:
• The system adjusts the flow temperature if the current flow
temperature is not sufficient to reach the set room temperature. In
the event of a defective valve or actuator, the system would gradually
increase the flow temperature.
• The flow temperature has a major influence on the efficiency of heat
pumps.
If the system has recognised this state (set room temperature is not
reached over a longer period of time), an error message is displayed.
The room (individual control) is no longer considered for the time being
when determining the flow temperature (adaptive heating curve). Once
the error has been rectified, a reset on UI 800 (Reset room temperature
monitoring) can be carried out. The room is then considered again when
determining the flow temperature. If the system recognises that the
room temperature has been reached again, e.g. because a jammed valve
has released itself, the system automatically resets the room
temperature monitoring for the room affected.
Detailed functional description
ϑ = 21 °C
RS
.
Q
ϑ = 17 °C
RS
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