1. Previous Minutes

2. Substation Planning

Two bunker layouts have been prepared, one to accommodate MGE UPS equipment and one for Gutor UPS equipment. At this stage, both have an overall length of 24m. Nigel commented that the length could go to 24.5m before reaching the next air conditioning duct and that the loading doors require reduced height over 5.1m length, not 4m as mentioned previously.

As yet, there is no provision for the installation of cooling and ventilation. Anne will provide Jukka with the heat dissipation and equipment requirements for each room in order that this can be prepared. Nigel suggested that this is an opportunity to review the overall cololing and ventilation arrangements in the area. Minimising the number of ducts crossing the S-206 corridor is desirable given the number of cables that must cross as well.

Anne stated that there will be a price enquiry to select the critical equipment UPS as well as for the physics equipment UPS. We therefore have to size the bunker without knowing which UPS solution(s) will be chosen. The UPS choice affects the size of the safe room and the low voltage switchgear room.

The easiest option is to size both the safe room and the low voltage room for the worst case scenario. Anne pointed out, however, that this would require a 25.2m bunker—this is longer than the 24.5m mentioned above and creates problems if the bunker length needs to be doubled for a 4MW solution.
Nigel commented that the bunker could reach as far as the bike shed and not just the corner of B513. Also, given the slope of the car park, at this point the bunker can extend further out towards Restaurant 2. It should therefore be possible to accommodate an additional 360m² if necessary.
It was therefore agreed to size the safe room and the low voltage room to accommodate either MGE or Gutor UPS systems. Anne and Nigel will optimise the clearances in these rooms to minimise the total length.

Anne commented that it is extremely difficult to prepare a bunker layout that allows easy expansion to support a 4MW load. The main reason for this is that the power demands for the air conditioning equipment required are not at all understood.

The key question is how to size the saferoom now. If this is too small for a 4MW total load then a radical reconfiguration would be required, probably involving a period of downtime.
Tony noted, however, that some radical change will be needed as the increase in total load will increase the air conditioning load to be supplied from the secured network. This will push the power available for critical computing equipment below an acceptable level. Alternative arrangements for supporting this equipment would therefore be required. Whatever the alternative solution is, it is likely that this would be installed outside the saferoom. There are thus two possible alternatives

The required secured network load for hvac equipment exceeds 1.4MVA. If this is the case, a major reconfiguration is required and it is pointless to worry now about the optimum size of the saferoom in this situation.
The required secured network load for hvac equipment is below 1.4MVA. Sizing the saferrom for this eventuality should be considered now. Fortunately, it seems no additional space would be required since the low voltage switchboards would be able to expand into space freed by moving the UPS for critical equipment.

Anne commented that a decision should be taken on the “service generaux” switchboards. There are two alternatives.

Install two 2MVA switchboards plus associated transformers and 18kV cells. An Upgrade would require duplication of this equipment and would be costly.
Install two 3MVA switchboards plus the associated transformers and 18kV cells. These would cover any likely future expansion but at higher initial cost.

Tony said that Anne should prepare a note setting out the costs of the two options so that he could discuss this with others.
Widening the 18kV switchgear room by 1.8m (from 4m to 5.8m) would be sufficient to allow for any foreseeable expansion. This could be considered, depending on the overall bunker length.
Jukka said he doubted a 4MW load could ever be cooled in B513. Tony replied that we need to know the maximum that can be cooled and what modifications are needed to the overall hvac system. For example, does all the pipework need to be changed or can additional pipework be installed in parallel? Tony again said that it is highly desirable to be able to support a 2MW load in the existing machine room (i.e. 1500m²) and not have to overflow into the barn.