B513 Meeting, 26^th June 2001

1. Vault air conditioning

• Jukka estimated the costs for provision of adequate smoke extraction at 80KCHF. A 630mm duct is required along the MG room side of the back wall. 1m of clearance is required for the fire dampers.
• The additional chiller that is required long term could be done next year. A full Market Survey and tender procedure is required—but not FC approval as the cost is estimated to be around 350KCHF.
• Space must be made for the additional chiller. Jukka proposes to remove the two hot water based humidifiers, leaving only the electrical humidifier. A single humidifier should be more than adequate as PCs work with 20-80% humidity. Jukka pointed out that we haven’t been using the hot water based humidifiers for quite some time.

2. LV distribution in the vault

• Anne distributed a document detailing the costs for a vault-wide LV distribution. It was noted that costs for harmonic compensation are not included; this may need to be at the low-voltage switchboard level.
• Anne will discuss implementation issues firther with the contractor and TIS.

3. HV supply for B513

• Various options for housing the proposed new substation were discussed.

a. Anne confirmed that all unrelated equipment (network cabling, …) must be removed from the 18kV cell area and that the 2MVA transformer should be “close” to low voltage switchboard—distances are normally of the order 10-15m.

b. Excavation down below the existing basement level (to provide adequate clearance for cables) is not ruled out. However, fresh air supply ducting would have to be rerouted and there would be constraints due to the piles supporting the building.

c. A rooftop location for the transformers would present difficulties for maintenance. Further, the building might need reinforcing as it is unlikely the roof could support even one or two 6tonne transformers.

• Jukka asked about the requirements for air conditioning if the transformers were to be located indoors. Anne replied that each transforter dissipated 10kW at full power. In this case, four transformers running at 50% load would dissipate 20kW. [Figures corrected after the meeting.]
• Finally, Anne commented that perhaps a total of five transformers would be needed—2MVA corresponds to only 1.8MW so an equipment load of 2MW could require three transformers and not two. (The other two transformers are required to support the anciliary and emergency loads.) Moving to a solution with three transformers could lead to an increase in UPS area—if we need more 400A modules or if larger the 500A modules are required. Anne will be refining the HV supply plans to clarify these details over the next couple of months.