BuildingSystems.Examples.Tutorial.SimpleHouse.SimpleHouse4

# .BuildingSystems.Examples.Tutorial.SimpleHouse.SimpleHouse4

Heating model

## Information

The wall temperature (and therefore the room temperature) is quite low. In this step a heating system is added to resolve this. It consists of a radiator, a pump and a heater. The radiator has a nominal power of 3 kW for an inlet and outlet temperature of the radiator of 60°C and 40°C, and a room air and radiative temperature of 20°C. The pump has a (nominal) mass flow rate of 0.1 kg/s. Since the heating system uses water as a heat carrier fluid, the media for the models in the heating circuit should be set to MediumWater.

#### Required models

- BuildingSystems.Fluid.HeatExchangers.HeaterCooler_u
- BuildingSystems.Fluid.HeatExchangers.Radiators.RadiatorEN442_2
- BuildingSystems.Fluid.Movers.Preconfigured.FlowControlled_m_flow
- BuildingSystems.Fluid.Sources.Boundary_pT
- Modelica.Blocks.Sources.Constant

#### Connection instructions

The radiator contains one port for convective heat transfer and one for radiative heat transfer. Connect both in a reasonable way. Since the heating system uses water as a heat carrier fluid, the media for the models should be set to `MediumWater`.

The `Boundary_pT` model needs to be used to set an absolute pressure somewhere in the system. Otherwise the absolute pressure in the system is undefined. Pressure difference modelling may be disregarded in the heating circuit since the chosen pump sets a fixed mass flow rate regardless of the pressure drop.

Set the heater input to 1, meaning that it will produce 1 times its nominal power.

#### Implementation

The pump and the heater need a control input, which we set here to a constant of 1. However, in the next version of this model, we want to connect an actual controller to these models. We can therefore introduce a `Boolean constant` (or a `Boolean parameter` would also work), and use this to conditionally remove the Modelica block that outputs the control signal. When Modelica removes such a block, then all connections to it will also be removed.

#### Reference result

The result of the air temperature is plotted in the figure below. The temperature rises very steeply since the wall is relatively well insulated (k=0.04 W/(m*K)) and the heater is not disabled when it becomes too warm.

## Revisions

- September 4, 2023, by Jelger Jansen:
  First implementation.

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