A global description of the OT water cooling system, as defined in the Invitation to Tender IT-3307/TS/LHCb (EDMS 549196.v1), can be found in the presentation by P. Guglielmini (NIKHEF, 19/05/2005). Links to the relevant technical documentation can be found below.
The OT consists of 3 stations perpendicular to the beam axis. The electronic boxes dissipating heat are arranged on the upper and lower sides of each station. The total heat dissipated by these modules is about 15 kW. Taking a safety factor of 1.5, the cooling system is designed with a dimensioning figure of 22.5 kW.
The primary sources of cooling water in LHC are the Chilled and Mixed Water, that shall be used in the LHC surface buildings in air handling units and in underground areas of UW and US in the heat exchangers. Chilled Water shall be produced at the temperature of 5 degrees and Mixed Water shall be produced at the temperature of 13 degrees. Links to the technical documentation concerning primary water cooling systems can be found below.
The OT is cooled down with demineralised water; the coolant is supplied at 19 degrees Celsius by an independent loop connected to the mixed water through a heat exchanger. The make-up of the coolant loop is made from the demineralised water network. All the elements of the cooling system (heat exchanger, pumps, three-way valves, filters, etc.) are gathered on a common rack that will be installed on a metallic platform in the accessible area close to the shielding wall. The demineralised water quality is ensured via an ion-exchange cartridge (water quality, 0.1 to 1 uS/cm). There are two pumps in parallel, one being used for backup.
