Waste Heat Recovery for the LHC Coooling Towers: Control System Validation Using Digital Twins

In order to improve its energy utilization, CERN will deploy a Waste Heat Recovery system at one of the LHC’s surface sites which will provide heating power to a local municipality. To study the effects that the heat recovery plant will have on the cooling system, a ’digital twin’ of the cooling plant was created in the simulation tool EcosimPro. The primary question of interest was whether the existing control system of the cooling plant would be capable of handling transients arising from a sudden shutdown of the heat recovery plan. The simulation was connected via OPC UA to a PLC implementing the cooling plant control system. This ’virtual commissioning’ setup was used to study a number of scenarios representing different cooling loads, ambient temperature conditions, and heat recovery plant operating points. Upon completion of the investigation it was found that the current cooling plant control system will be sufficient to deal with the transients arising from a sudden stop of heat recovery plant operation. In addition, it was shown that an improvement in the controls could also enhance the energy savings of the cooling towers.