GroundWaterCollector

Use

The model reproduces a heat exchanger which extracts heat out of ground water to a heating medium. The heat is exchanged over the hole length of the underground system. This includes the parts only in contact to the ground. It can be used as heat source for the heat pump model or as cold source.

Parameters and Connectors

This model is based on the assumption of flowing groundwater through the affected ground. This is modeled by the parameters TGroundWater, qvGroundWater, cpGroundWater and rhoGroundWater. The model is mapping the heat transfer from the affected ground and the ground water around the heat exchanger to the heat transfer medium. The medium is connected via the ▶SourceOut and ▶SourceIn pipe connections. In order to map the floor not affected by, it is necessary to connect the ▶EnvironmentConditions. The parameters for the ground (cGround, rhoGround, lambdaGround and GeoGradient) set in the environment block are decisive here. The affected ground is adjacent to the unaffected ground and the heat exchangers as well as the ground water.

To characterize the GroundCollector, the radius of the affected ground around the HeatExchanger (rAffected) as well as the depth (HoleDepth) and the radius (rHole) of the HeatExchanger must be specified. The rHole parameter describes the pipe radius.

The system size can be defined using the number of HeatExhangers (numberHE) and the volume of the HeatExchangers (VHE). The heat transfer medium in the heat exchanger is characterized by the specific heat capacity cpMed and the density rhoMed. The transition between the medium and the affected ground is described using the parameter alphaHeatExchanger.

In addition, the properties of the heat transfer medium must be set via cpMed and rhoMed.

Model Background

Here is a figure to illustrate the parameters:

It is assumed that the affected grounds of the HeatExchangers do not influence each other and that all heat exchangers are used parallel. This means that the affected ground has the same temperature for all heat exchangers. The temperature of the affected ground is determined by the heat input or extraction of the medium as well as the heat conduction between the affected and unaffected ground. Seasonal influences, characterized by TAverageAmbientAnnual, TAmbientMax and MaxMonth in the environment model, are also taken into account for the affected and unaffected ground. The vertical collector is calculated using the mean depth (temperature at HoleDepth /2), as the model assumes a uniform ground temperature over the entire ground depth. It is also assumed that the groundwater transfers all of its heat to the affected Ground, so that it continues to flow at the temperature of the affected ground.