modelBuoyancy1
Extends from BuildingSystems.Technologies.ThermalStorages.BaseClasses.BuoyancyModels.PartialBuoyancy.
Information
The Buoyancy model increments the heat exchange between layers when the upper layer is colder than the lower one.
Main equations
The Buoyancy effect is defined by the following equation, Q=G*dT*nEle^exp_nEle
Typical use and important parameters
G. Its value determines the buoyancy effect and is defined as, G = if nEle <
10 then 0.8*nEle+16 else 26-0.2571*nEle, see reference.
Validition
Technical information and measurements from the commercial DHW tank Vitocell 100-V, type CVW of 390 l were used to tune the parameters of the model, see references. Furthermore, the buoyancy model is valid for values ofnEle between 5 and 40.
References
The Buoyancy Model is based on the following reference; "De Coninck et al. (2013) - De Coninck, R., Baetens, R., Saelens, D., Woyte, A., & Helsen, L. (2013). Rule-based demand side management of domestic hot water production with heat pumps in zero energy neighbourhoods. Journal of Building Performance Simulation".
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Integer | nEle (from PartialBuoyancy) | Number of layers | |
| Modelica.Units.SI.ThermalConductance | G | if nEle < 10 then 0.8*nEle + 16 else 26 - 0.2571*nEle | Equivalent thermal conductance between layers |
| Real | exp_nEle | 1.5 | Exponent for nEle |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a[nEle - 1] | port_a (from PartialBuoyancy) | Heat port of the bottom volume | |
| Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_b[nEle - 1] | port_b (from PartialBuoyancy) | Heat port of the top volume |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.TemperatureDifference[nEle - 1] | dT (from PartialBuoyancy) | Temperature difference between layers | |
| Modelica.Units.SI.HeatFlowRate[nEle - 1] | Q_flow (from PartialBuoyancy) | Heat flow rate from port_a -> port_b |