Heating network
Introduction and Model¶
The heating network uses water as a heat transfer medium to transport heat generated by CHP units and boilers to the anaerobic digester to maintain its operating temperature. To prevent overheating, a cooler removes excess heat from the network, keeping the temperature regulated.
The heating network is implemented as a balance of heat energy, where CHPs and boilers are heat producers and the anaerobic digester and cooler are heat consumer. The new temperature of the heating network is calculated with the resulting heat input or output of the energy balance. The heat network operates at a defined temperature range of 70-80 °C and a volume flow of 50 m3/h.
Equations¶
Heat energy balance¶
\[ \dot Q_{res} = \sum \dot Q_{boiler} + \sum \dot Q_{CHP} - \dot Q_{ferm} - \dot Q_{cooler} \]
| Symbol | Description | Unit |
|---|---|---|
| \(\dot Q_{res}\) | Resulting heat input or output of heat balance | kW |
| \(\dot Q_{boiler}\) | Heat input of a boiler | kW |
| \(\dot Q_{CHP}\) | Heat input of a CHP unit | kW |
| \(\dot Q_{ferm}\) | Heat output of the anaerobic digestor | kW |
| \(\dot Q_{cooler}\) | Heat output of the cooler | kW |
Temperature of the heating network¶
\[ T_{new} = T_{old} + \frac{\dot Q}{ \dot m_{H2O} \cdot \frac{c_{p,H2O}}{3600}} \]
| Symbol | Description | Unit |
|---|---|---|
| \(T_{new}\) | New temperature after heat input or output | °C |
| \(T_{old}\) | Old temperature before heat input or output | °C |
| \(\dot Q_{res}\) | Resulting heat input or output of heat balance | kW |
| \(\dot m_{H2O}\) | Mass flow of water | kg \(\cdot\) h-1 |
| \(c_{p,H2O}\) | Specific heat capacity of water | kJ \(\cdot\) kg-1 \(\cdot\) K-1 |
Source code documentation¶
mod heat_net
mod heat_net_init