Ambient temperatures (DHW wizard options)

The respective ambient temperatures are of particular importance when calculating the cold water temperatures after a stagnation phase and the discharge times for overheated cold water. For this reason, the ambient temperatures must be determined on a project-specific basis depending on the installation conditions before the calculation.

You can either enter the Ambient temperature for hot water (PWH) and cold water (PWC) in the input fields or click on the respective button to work with the default values and adjust them if necessary.

Note:

The default values for ambient temperatures result from a heat balance that takes into account the heat sources in the shaft and the transmission heat transfer at the shaft enclosure surfaces. The room air temperatures in the bathroom were assumed to be 24 °C and 22 °C in all other neighbouring rooms. Fire insulation is assumed in the ceiling area in each case.

The planner is responsible for adapting the suggested values to the specific project, taking into account the local conditions.

Distribution pipe area:

You can specify the ambient temperatures here according to the installation of the distribution pipework. Exposed distribution lines in heated corridors or rooms result in higher ambient temperatures than exposed lines in unheated corridors or rooms.

Table 1. Suggested values for the ambient temperature depending on the type of installation
Type of installation	Default value PWH [°C]	Suggested value PWC [°C]
Exposed in heated corridors/rooms	22	22
Uncovered in unheated corridors/rooms	10 (worst case in winter)	15 (worst case in summer)

Rise/fall pipe area:

Here you can specify the ambient temperatures according to the shaft assignment. Selecting the respective shaft assignments results in different default values for the ambient temperatures depending on the number of heat-emitting pipes:

Table 2. Ambient temperature depending on the duct assignment:
Shaft assignment	Default value PWH [°C]	Suggested value PWC [°C]
Four heat emitting pipes	27	27
Three heat emitting pipes	26	26
Two heat dissipating pipes	25	25
One heat emitting pipe	24	24
Without heat dissipating pipe	23	23

Note:

If you only have one shaft for PWC and PWH, the same shaft assignment must be selected for PWH and PWC.

Floor distribution pipe area:

You can define the ambient temperatures here according to the installation density of your installation. With a high installation density in the suspended ceiling, the heat dissipation to the environment results in higher ambient temperatures than with a low installation density or a freely laid installation.

Table 3. Ambient temperature depending on the installation density:
Installation density	Default value PWH [°C]	Suggested value PWC [°C]
High installation density	30	30
Low installation density	27	27
Free installation	24	24

Floor line / floor ring line / individual supply line area:

Here you can define the ambient temperatures according to your desired installation type.

Table 4. Default values for the ambient temperature depending on the type of installation
Installation type	Default value PWH [°C]	Default value PWC [°C]
circulating	27	27
circulating thermally decoupled	27	24
non-circulating	25	24

With Back you can revise the settings you made previously.
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