modelUPreinsulated
U model for Preinsulated pipes
Extends from BuildingSystems.Technologies.DistrictHeatingNetworks.UndergroundPipes.BaseClasses.DHN_Umodels.UPartialClass.
Information
Main equations
U1 = (Rg+Ri)/((Rg+Ri)^2-Rm^2)
U2 = (Rm)/((Rg+Ri)^2-Rm^2)
Implementation
In case U1 > 4*U2, the value of U2 is set to 0. It means the interaction between pipes is negelcted.
References
On transient heat losses from buried district heating pipes, Bomm 2000.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| General › Laying | |||
| Modelica.Units.SI.Length | H_real | Depth of the pipe center | |
| Modelica.Units.SI.Length | E | Distance between pipes' centers | |
| General › Geometry | |||
| Modelica.Units.SI.Diameter | d_g | 1.313 | Diameter of the undisturbed ground |
| General › Thermal properties | |||
| Modelica.Units.SI.ThermalConductivity | lam_g | 1.2 | Heat conductivity of the undisturbed ground |
| Assumptions | |||
| Modelica.Units.SI.CoefficientOfHeatTransfer | h_gs | 14.6 | Heat transfer coefficient at the ground surface |