Page 43 - Advanced Course

KNX ADVANCED COURSE

Flow temperature (°C)
100°C
90°C
80°C Characteristic curve
70°C with ambient
60°C temperature
50°C Characteristic curve
without ambient
40°C temperature
30°C
20°C
10°C

+20°C +10°C 0°C -10°C -20°C
External temperature (°C)

Figure 15: Ambient temperature

1.3.3 Capacity of the Heating Elements

Depending on the type of building (old building, new building, low-energy house…) and
type of room, there are formulae and tables for producing the size or capacity of the
heating elements.
Rule of thumb: 100-120 W per m² (room height of 2.60m, 2 external walls, no large
window surface)
Special requirements should also be considered (e.g. rapid reaction time in the warm-up
phase). Since specific setpoint temperatures are provided depending on the room usage,
a table is produced with the heating capacity of the heaters.

Note: A reduction in the room temperature by 1°K causes an energy saving of 6%!

Overall Heating Heating capacity ( W )
length surface at t V 75°C, t R 65°C
mm m² 15°C 18°C 20°C 22°C 24°C

Overall height
500 mm

600 3,582 999 931 886 842 799
700 4,200 1165 1086 1033 982 932
800 4,816 1332 1241 1181 1123 1065
900 5,436 1498 1396 1329 1263 1198
1000 6,052 1665 1552 1477 1403 1332
1100 6,668 1831 1706 1624 1543 1464
1200 7,286 1998 1862 1772 1684 1598
1300 7,904 2164 2017 1919 1824 1731
1400 8,520 2330 2171 2066 1964 1864
1600 9,754 2663 2482 2362 2244 2130
1800 10,992 2996 2792 2657 2525 2396
2000 12,387 3329 3102 2952 2806 2663
Figure 16: Example of the heating capacity of a duplex heater with an overall height of 500
mm (information from the manufacturer)

Home and Building Management Systems KNX Association
HVAC Control with KNX HVAC_E0813b.doc Page 18/60