REMKO CMF-120-1P - Manual (Page 8)

REMKO CMF / CMT
Layout
Building type Specific heating output in W/m 2
Passive energy house 10
Low-energy house built in 2002 40
according to energy conservation
order regarding heat insulation 1995
60
Modern building constructed around 1984 80
Partially-renovated old building
constructed pre-1977
100
Non-renovated old building
constructed pre-1977
200
graphically from the heat pump's
temperature-specification heat-output
diagram. (In the example, 35 °C for
a floor heating-system). Next, the
heat load for the standard outdoor
temperature (the lowest temperature
of the year locally) and the heat
threshold are marked on the graph.
The outdoor-temperature-dependent
heating requirement, simplified here
as a straight-line relationship between
heat-load and the start of the heating
season, is recorded in the graph of
heat-load curves. The intersection
of the two straight lines with the
max. heat-load curve is plotted on
the X axis, where the balance-point
temperature is read. (in the example,
ca.-4°C) The least load of the 2nd heat
source is the difference between heat
load and the heat pump's maximum
heat output on these days. (In the
example, the capacity necessary to
cover peak loads is ca. 6 kW.)
An approximate allowance for
heating water - per person
according to VDI 2067: 0.2 kW
A residential home comprised of 150
m² living-space and a heat requirement
of 100 W/m² has been selected for
the example design. A total of five
persons live in the house. The heat
load amount to 15 kW. Adding a
drinking water allowance of 0.2 kW
results in a required heat output of
16 kW. Depending on the power
company, an additional charge must
then be made in order to factor in the
service time-out period. The rating
and determination of the heat pump's
balance-point temperature derives
A precise calculation of the
building's heating load according to
EN 12831 is required for the design
and dimensioning of a heating
system. However, approximate
requirements can be determined
based on the year of construction
and the type of building. The
adjacent table shows the
approximate specific heating loads
for a number of building types. The
required heating system output can
be calculated by multiplying the area
to be heated with the given values.
For a precise calculation, various
factors must be considered. The
transmission-heat requirement,
the infiltration heat-loss and
an allowance for water heating
comprise the total heating output
which the heating system must
provide.
The total area of the floor surfaces,
exterior wall windows, doors
and roofing is required in order
to determine the transmission
heat requirement. In addition,
information about the materials
used in the building is required,
as these lead to extremely varied
thermal transmission coefficients
(the so called K value). Also required
are the room temperature and the
standard outdoor temperature,
that is, the lowest outdoor-
temperature on average that will
occur during the year. The equation
for calculating the transmission-heat
requirement is
Q=A U (t
R
-T
A
) and must be
calculated separately for all room-
enclosure surfaces.
The infiltration heat requirement
takes into consideration how often
the heated room air is exchanged
for cold external air. The room
volume (V), the air exchange
frequency (n) and the specific heat
capacity (c) of the air is also required
in addition to the room temperature
and average low temperature.
The equation is:
Q=V x n x c (t
R
-t
A
)
Diagramm Auslegung
0
5
10
15
20
25
30
-15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Heat output at a supply temperature of 35°C
Heat
output [KW]
Outdoor temperature [°C]
Heat load according to
DIN EN 12831
Minimum
performance
2. heat source
Standard outdoor temperature Bivalent temperature
Heat load
Heat load plus warm-
water requirements and
service time-out period
n-min
Rated frequency 76/77 Hz
n-max
Heating threshold for old construction
according to VDI 4650
8