.IDEAS.Fluid.Taps.Interfaces.BalancedTap

Information

Description

Partial model of a domestic hot water (DHW) system composed mainly of a thermostatic mixing valve. The model foresees a cold water flowPort which has to be connected to the system (eg. storage tank).

The model has two flowPorts and a realInput:

• port_hot: connection to the hot water source (designation: hot)
• port_cold: connection to the inlet of cold water in the hot water source (designation: cold)
• mDHW60C: desired flowrate of DHW water, equivalent at 60°C

In a first step, the desired DHW flow rate at 60°C is corrected for the set temperature TDHWSet. The model tries to reach the given DHW flow rate at a the desired mixing temperature TDHWSet by mixing the hot water with cold water. The resulting hot flowrate will be extracted automatically from the hot source, and through the connection of port_cold to the hot source, this same flow rate will be injected (at TCold) in the production system.

There are currently two implementations of this partial model:

1. Reading in mDHW60c from a table
2. Getting mDHW60c from a realInput

Assumptions and limitations

1. No heat losses
2. Inertia is foreseen through the inclusion of a water volume on the hot water side (default=1 liter). This parameter is not propagated to the interface, but it can be changed by modifying pumpHot.m. Putting this water content to zero may lead to numerical problems (not tested)
3. If THot is smaller than TDHWSEt, there is no mixing and TMixed = THot
4. Fixed TDHWSet and TCold as parameters
5. The mixed DHW is not available as an outlet or flowPort, it is assumed to be 'consumed'.

Model use

1. Set the parameters for cold water temperature and the DHW set temperature (mixed)
2. Connect port_hot to the hot water source
3. Connect port_cold to the cold water inlet of the hot water source
4. Depending on the implementation: fill out the table or provide a realInput for mDHW60C
5. Thanks to the use of ambient components in this model, it is NOT required to add additional pumps, ambients or AbsolutePressure to the DHW circuit.

Validation

The model is verified to work properly by simulation of the different operating conditions.

Examples

An example of this model is given in IDEAS.Fluid.Domestic_Hot_Water.Examples.DHW_example and IDEAS.Thermal.Components.Examples.StorageTank_DHW_HP.

Contents

Name	Description
Medium

Revisions

• 2013 June, Roel De Coninck: documentation.
• 2012 September, Roel De Coninck, simplification of equations.
• 2012 August, Roel De Coninck, first implementation.