Dimensioning

BS EN 1264-3:2021 pdf free.Water based surface embedded heating and cooling systems Part 3: Dimensioning.
For ceiling heating systems, the specifications and Formula (1) given in 4.1.1.1 apply.
4.2.1.2 Characteristic curve
For ceiling heating systems, Formula (2) and the respective specifications given In 41.12, apply. The gradient KH is determined according to EN 1264-2 and EN 1264-5. For detailed information about the procedure, see EN 1264-5.
4.2.1.3 Field of characteristic curves
In principle, the specifications given in 4.1.1.3 also apply. With respect to the calculation method (see EN 1264-5), the fIeld of characteristic curves should contain the values of R)B specified in 4.1.1.3, even though not all together are needed for practical application.
4.2.1.4 Limit curve
Physiological limititions concerning the surface temperatures of ceiling heating systems depend on geometrical conditions, i.e. in practice on the respective application. Therefore, in this document only average conditions can be taken into consideration. Consequently, it is emphasized, in practical engineering the real conditions shall be taken into account.
For rooms with a height 2,7 m, the average surface temperature (see EN 1264-1:2020. 3.4.2) should not exceed 0F,m = 33 °C. As a result, the limit curve within the field of characteristic curves is a horizontal straight line in the distance q (see below).
Using the heat transfer coefficient a = 6,5 W/(m2K) coming from EN 1264-5, the limit of the specific output at a room temperature of 20 °C results to:
q = 85 W/m2 (rounded)
At room heights > 2,7 m the average surface temperature of the heated ceiling can be increased. If values “Fm > 33 °C are used, the compliance with physiological limitations should be proved. In general, refer to EN ISO 7730.
4.2.2 Boundary conditions
4.2.2.1 Flow pipes to adjacent rooms
The same procedure described in 4.1.2.1 applies.
4.2.2.2 Thermal insulation
To limit the heat flow through the ceiling to rooms above, the required thermal resistance of the insulating layer RAIfl (in principle see FigureA.3) shall be at minimum in accordance with EN 1264-4:202 1, Table 1.
As for the rest, the content of 4.1.2.2 applies accordingly.
4.2.3.1 Pressure loss
The maximum pressure loss per heating circuit should not exceed 250 mbar in order to limit the electrical power consumption of the pump, e.g. by hydronic balancing (see EN 1264-4:2021, 4.1).
4.2.3.2 Design specific thermal output
It is recommended to apply the procedure described in 4.1.3.2 accordingly.
4.2.3.3 Determination of the design flow temperature
It is recommended to apply the procedure described in 4.1.3.3 accordingly. In the case ot operating with floor heating connected in parallel and using uniform flow temperature, the flow temperature of the floor heating system shall be used.
4.2.3.4 DetermInation of the water flow rate
It is recommended to apply the procedure described in 4.1.3.4 accordingly taking into account the reversed position of the structure shown in Figure A.3 and the changes of the transfer resistances on the surfaces as follows:
1/cr is the heat transfer resistance on the heating ceiling surface; 1/cr = 0,154 (m2K)/W;
Ra;ceiiiiigIS replaced by Ra;iloor, the heat transfer resistance on the floor above the ceiling heated room;
Ra;oor = 0,10 (m2K)/W.
4.3 Wall heating systems
4.3.1 Basic principles
NOTE The test results coming from EN 1264-2 and EN 1264-5 are valid for wall heating systems where the respective wall is fully covered with the heating surface. But the accuracy is also sufficient for cases where the wall is partially covered.
The descriptions given for ceiling heating systems (see 4.2.1.1 through 4.2.1.3) also apply for wall heating systems (in the respective wordings replace ceiling heating by wall heating”).
Concerning the limit curve depending on physiological considerations, refer in principle to the first statement in 4.2.1.4. For wall heating systems the average surface temperature (see EN 1264-1:202 1, 3.4.2) should not exceed 9Fm = 40°C. As a result, the limit curve within the field of characteristic curves is a horizontal straight line in the distance q (see below).
4.3.2.2 Thermal insulation
To limit the heat flow through the wall to rooms adjacent or to the external environs, the required thermal resistance of the insulating layer RA1fl (in principle see Figure A.3) shall be at least in accordance with EN 1264-4:202 1, Table 1.
As for the rest, the contents of 4.1.2.2 apply accordingly.
4.3.3 Design
4.3.3.1 Pressure loss
The maximum pressure loss per heating circuit should not exceed 250 mbar in order to limit the electrical power consumption of the pump, e.g. by hydronic balancing (see EN 1264-4:2021,4.1).
4.3.3.2 Design specific thermal output
It is recommended to apply the procedure described in 4.1.3.2 accordingly.
4.3.3.3 Determination of water flow temperature
It is recommended to apply the procedure described in 4.1.3.3 accordingly. In the case of operating with floor heating connected in parallel and using uniform flow temperature, the flow temperature of the floor heating system shall be used.
4.3.3.4 Determination of the design heating water flow rate
It is recommended to apply the procedure described in 4.1.3.4 accordingly taking into account the changed position of the structure shown in Figure A.3 and the changes of the transfer resistances on the surfaces as follows:
1/a is the heat transfer resistance on the heating wall surface; 1/a = 0,125 (m2K)/W;
Ra;ceiiingis replaced by Ra.back, the heat transfer resistance on the surface of the back side of the wall;
Ra.back = 0,13 (m2.K)/W, in case of adjacent rooms;
Ra.back = 0,04 (m2K)/W, in case of outside environments.
5 Cooling systems
5.1 General
5.1.1 Basic principles
The content of the following clauses, for cooling systems embedded in floors, ceilings and walls apply.
5.1.2 Temperature differences
Temperature differences are formulated in such a manner that the thermal output gets positive sign; i.e. cooling output and heating output are not distinguished by sign.
5.1.3 Regional dew point and standard indoor room temperature Cooling systems shall operate within a temperature range above the dew point 9pp. A regional dew point oDp,R shall be specified depending on the respective climatic conditions. In this document the
default value is 9Dp,.RO= 18。C, corresponding with an air moisture content ofx= 13 g/kg. If for design other regional values oDp,R are applicable or design values 9pp,des are set (for instance if air is dehumidified), these values shall be used (see 5.2.3.2).
In this document for cooling systems the standard indoor room temperature is specified to 9= 26 °C. If other values are designed, these shall be taken into consideration.
5.1.4 Temperature difference between room and cooling water
The temperature difference 08c between room and cooling water is calculated using Formula (16), corresponding with the procedure for heating systems, i.e. the effect of the temperature increase of the cooling water is taken into account as well.BS EN 1264-3 pdf download.Dimensioning