Calculation Basis

The water-ground pump flow rate is measured by the following formula:

Q = m x c x Δt


The water-ground pump flow rate in kilograms is measured as follows.

Q=Heat quantitykwh
m=Masse (Umlaufmenge)kg
c=Mass (circulated quantity)wh
   kg x K
Δt=Temperature differenceK (Kelvin)
In our case the temperature difference between the water-ground input and output (please observe the information provided by the heat pump producer; usually 3-5 K).









c: The specific calorific power is:
kg x K

As the probes generally operate on glycol/water mixture and glycol decreases the calorific power,
we calculate based on a simplified method with the following value:

kg x K

The heat quantity (required collection power) and the temperature difference are known; we need the circulated water-ground quantity.
Therefore, we transform the formula as follows:

c x Δt

Computation example:

Collection power 8 KW = 8000 W, considered temperature difference = 3,4 K


m=8000 wh x kg x K=2353 kg
1,0 wh x 3,4 K

m = 2353 kg is the water-ground quantity, circulated/hour = volumetric flow rate = 2353 L/h

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