City Heat Pump Network: Dispatch & Thermal Storage (2D)

Network Conditions

Ambient temperature 2 °C

Plant capacity (each of 3) 500 kW

Thermal storage size 2000 kWh

Buildings served 180

Live Readout

Heat pump COP

Storage level

Heat demand

Heat supplied

Electricity draw

Unmet demand

How it works

Each of the three plants is an electric heat pump lifting heat from ambient air to a 55°C supply main. Its coefficient of performance follows a Carnot-limited model at 45% of the theoretical maximum:

COP = 0.45 × T_supply / (T_supply − T_amb)   (Kelvin)

Building heat demand follows a heating-degree model: a fixed base load (hot water) plus a slope term that grows as ambient temperature falls below the 18°C balance point, multiplied by the number of buildings on the network.

When plant output exceeds demand the surplus charges the thermal storage tank, rate-limited to 15% of its capacity per simulated hour. When demand exceeds the plants' combined capacity, storage discharges (up to 25%/hour) to cover the gap; if storage empties first, the shortfall shows up as unmet demand — buildings that go cold. Electricity draw is heat supplied divided by COP, so a cold snap both raises demand and drops COP at the same time, which is why cold snaps are the network's real stress test.

Supply flow (hot) Storage tank Return flow (cool)