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:
 1.160 wh 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:

 1.00 wh 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:

 m = Q 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