modelHeatpump_DHN

Information

Purpose of model

A simple model of a heat pump. A pump for the circulation of the district heating network heat carrier is included. The model calculates the electric power of the heat pump from a given heat flow rate and a coefficient of performance. The COP is calculated based on the Carnot COP and a constant efficiency factor (parameter). The Carnot COP depends on the supply temperature, that is given by an input and the temperature of the heat source. The pressure difference set by the circulation pump of the hydraulic grid is set with an input. An electric power consumed by the circulation pump is calculated.

Level of detail, physical effects considered, and physical insight

• variable COP dependent on the supply temperature of the DHN and the source temperature
• constant efficiency factor for the COP calculation from the Carnot COP
• the electric power and therefore, the heat flow that can be produced is limited by a parameter
• a static mass balance is assumed

Interfaces:

Q_flow_set: the heat flow that needs to be provided by the heat pump

T_set_variable: The temperature of the heat source

dp: The pressure difference that has to be provided by the pump inside the producer

Governing Equations:

COP_Carnot=(T_set_variable +273.15+ Delta_T_internal)/(T_set_variable +273.15+ 2*Delta_T_internal - T_source_internal)

COP=eta_HP*COP_Carnot

P_el=Q_flow_set/COP;

Mass balance: m_in+m_out=0

Remarks for usage:

Reverse flow is not supported

Version History

Model was created by Jan Westphal (j.westphal@tuhh.de) August 2025

Parameters

Connectors

Components