LINEAR Solutions 26 for AutoCAD

Detail on “Heat Interface Units in Sub-Network"

Information on the Heat Interface Units in the Sub-Network dialog in the Rohrnetzberechnung Quartiersnetze.

In this dialog, you create the heat interface unit that are considered by the sub-network end in the calculation. For example, you can include future network expansions in the calculation. The resulting capacity output is then determined and transferred to the component data at the sub-network end.

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Project Tab ➤ Discipline District Networks ➤ Analyse Tab ➤ Command group Analyse ➤ Components ➤ Technical Data … ➤ Selecting a Sub-network End ➤

Dialog “Heat Interface Units in the Sub-Network" of the LINEAR Solutions for Autodesk AutoCAD

Click in the table to create the row for the first entry and enter the individual values for the heat interface unit. You can then use the F5 key as an alternative to clicking on an empty row in the table to add the next row. With F6 or the Delete key, selected rows can be removed from the table.

Column Description
Qty.

Defines the number of heat interface units to be considered for the entry.
Name Defines the name of the heat interface unit..
Temperature F, DW Defines the return temperature of the domestic water.
Efficiency Determines the efficiency, which affects the Heat Capacity and Mass Flow Rate of the primary side. The efficiency depends on the thermal efficiency of the heat interface unit, the temperature difference between flow and return and the quality of the control system.
Capacity HT Determines the heat capacity required for heating on the secondary side.
Capacity DHW Determines the capacity required for DHW on the secondary side.
Temperature DHW Defines the required temperature for the processing DHW.
Volume Flow Rate DHW Determines or indicates the volume flow rate required for the preparation of domestic hot water hot based on the values entered.
Capacity Prim. Determines or indicates the heat capacity required on the primary side according to the values entered.
Mass Flow Rate Prim. Determines the required mass flow rate on the primary side or indicates this according to the values entered.
Diversity

Diversity

Drop-down list to select of the diversity of secondary side. Diversity determines how many consumers on the secondary side draw heat at the same time and thus to what share the required capacity of the heat interface unit is considered in the network. The following options are available:

  • 100%: All consumers are considered at full capacity at the same time. This method is usually used as a worst-case approach or for test scenarios without reduction through diversity.
  • DS 439: Danish standard for typical load profiles of the secondary sides in local and district networks. Due to the consideration of realistic usage distributions, the DS 439 is suitable for practical network simulations.
  • VDI 2072: VDI 2072 should be used for secondary sides in which centrally heated DHW is provided via fresh water stations or centralized systems. This guideline realistically determines the simultaneous tapping capacities, which form the basis for storage tank, transfer and network dimensioning. By combining usage profiles and empirical data, this method yields results that are significantly more practical than, for example, a simple generalized estimate according to Winter.

    Typical areas of application are networks in which several users draw DHW at the same time but not permanently, for example, apartment buildings with fresh water stations and districts with central heat supply and decentralized fresh water stations such as hotels, residential complexes or public buildings.

  • Winter: In this method, it is simplistically assumed that there is an increased diversity demand on the secondary side during the heating season. The method is suitable for mapping conservative load peaks in winter operation due to the increased diversity by adding heating and DHW demand. It should be noted that usually, when adding these two loads together, it is not the case that the full DHW and heating loads occur simultaneously. The use of this method therefore leads to very high mass flow rates and large pipe dimensions.
Priority Circuit

The Priority Circuit option is only available if the capacity data is calculated via the secondary side and the configuration VDI 2072 is selected for Diversity.

Enabled: If necessary, the heat capacity for heating is reduced or switched off to ensure sufficient capacity for DHW heating.