Optimising the energy demand

Energy and mass balance are basic tools for site evaluation and they are always the starting point of our energy consulting service.

The inital situation

The analysed industrial enterprise in the area of Graz/Austria has a high process-related demand for cooling power. Furthermore, during summer additional cooling power is required for air conditioning of company-owned buildings. Besides, difficulties in fulfilling the heating and cooling demand arise due to certain given boundary conditions of the nearby water stream. The demand of cooling power is covered with several systems as follows:

  • Two cooling circulation systems are connected to the nearby water stream. Cooling power is extracted at the allowed temperature range and is provided over heat exchangers for the divers recipients.
  • A smaller cooling power is provided by two wells at lower temperatures. This extracted ground water serves for special cooling requirements (cold water).
  • If the cold water extracted from the wells is not sufficient additional drinkingwater, provided by the municipal is fed into the cold water circuit.
  • Beside these main suppliers there are additional refrigerating machines with connected air- cooling towers covering the cooling demand for special purposes.


The well systems existing in this company have reached their capacity limit. Moreover the oil removal system is hydraulically overstrained. The scope of this analysis is to find out the capability of cost reduction.

Plausibility check

The parameters for partial load and for design working load are verified with the help of consumption values. The analysis reveals that the heat is dissipated:

  • to ca. 75% over the cooling systems at the nearby water stream
  • to 15% over the waste water of the oil removal system and
  • to 10% over the sewer.

Furthermore it reveals that, with a coincidence factor of 80%, the total amount of heat to be dissipated reaches about 3 MW. The cooling power provided by the cooling device maximally amounts to 430 kW.

Simulation of other cases

If required it is possible to simulate other load cases with the computer model such as:

  • Extension of workshop
  • Extended operating time
  • Increasing capacity utilization
  • Different temperatures
  • Different calculation factors

Release of a cold water set

  • Utilization of the nearby water stream for re-cooling the refrigerating machine
  • Planning an adequate supply system


The cooling system at the nearby water stream is able to provide the required cooling power for all listed load cases. A feeding of well or drinking water should not be necessary during normal operation. For cold water it makes sense to implement a new cooling device.

=> Reference

EnviCare® Engineering GmbH
engineering consultant for process technology

Eisteichgasse 20/36

8042 Graz, Austria
Tel. +43-316-381038-0 Fax+43-316-381038-9
e-mail: envicare@utanet.at

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