modelHeatPump_LowTemperatureDHN

Information

Purpose of model

A model of a heat exchanger that is combined with a heat pump. It is used in substation models of cold district heating networks where heat pumps are used to increase the temperatuer of the heat carrier.

Level of detail, physical effects considered, and physical insight

L2 (defined in the CodingConventions)

• no pressure losses considered
• static mass balance
• constant fluid properties
• dynamic energy balance
• heat transport based on Q_flow_nom and a delta_T_nom

Interfaces

inlet: A fluid inlet for the inflowing heat carrier medium

outlet: A fluid outlet for the outflowing heat carrier medium

heatPortS: A heat port for transporting the heat from the heat carrier to the building

heatPortR: A heat port for transfering the return temperature of the dwelling heat system to the heat exchanger, no heat is transfered

Governing Equations

Mass balance: m_in+m_out=0

Energy balance: V*rho*dh/dt=m_in*h_in+m_out*h_in-Q_flow_DHN

P_el=Q_flow_House/COP

COP = eta_carnot * eta_pl * (T_m_house + delta_T_HP) / (T_m_house - T_m_DHN + 2 * delta_T_HP)

Q_flow_House=Q_flow_DHN+P_el

Heat transport: Q_flow_house = Q_flow_nom_house *(T_house_supply - T_house_return) / delta_T_house_nom

References

The model was used to create a substation for cold district heating networks

TransiEnt.Consumer.Heat.Consumer_LowTemperatureDHN

Version History

Model was inserted by Jan Westphal (j.westphal@tuhh.de) January 2025

Parameters

Connectors

Components