B513 Meeting, 10th September 2002

Present:           Tony Cass, Anne Funken, Jukka Lindroos

1.             Previous Minutes

  1. Approved with minor corrections.

2.             Possible cooling solutions for the UPS systems

  1. Both MGE and Gutor provide detailed specification of the air conditioning requirements for their UPS systems. These specifications are designed to maintain the temperature within the optimum range of 15°-25°C. The fixed temperature difference (10°C) leads to certain requirements in terms of air flow per hour; this is thus the critical factor when considering how the UPS units can be accomodated in the existing areas.
  2. Direct water cooling of the UPS modules is not possible and, given the air flow requirements, environmental conditions in the room are optimised if this flow is through the room rather than being recirculated.
  3. The existing UPS room has a dedicated air conditioning and a duct from the machine room air conditioning stations. Together, these support an air flow of up to 35,000m3hr. If an extra dedicated unit is installed to replace the machine room air conditioning, an air flow of up to 43,000m3/hr can be supported.
  4. The possible configurations for the MGE and Gutor UPS systems, and the additional space required, are as follows.

 

35,000m3/hr

43,000m3/hr

 

In UPS Room

Extra Space

In UPS Room

Extra Space

MGE UPS
(12 modules)

8 modules and filters

70m2

8 modules and 200kW UPS

55m2

Gutor UPS
(15 modules)

5 modules and 200kW UPS

120m2

10 modules

80m2
  1. Jukka pointed out that an additional dedicated unit for the UPS room is required anyway as the cold air from the stations is required to support the foreseen heat load in the machine room. This unit could be accomodated in the new technical area created during the vault conversion. A duct would be required at ceiling level; this is not incompatible with the clearance requirements of either UPS system.
  2. Given this information, it was agreed that Anne would prepare a bunker layout assuming that an additional 80m2 is required for the UPS systems. The plan should assume an initial “physics” UPS capacity of 800kVA and use the possibility of staging the increase to the full 2MW size to maximise the reuse of existing areas.
  3. Anne pointed out again the difference in layout that would be needed if an autonomy of 2 hours is required for the critical load UPS—the batteries for this UPS can no longer be accomodated in the safe room.

3.             Cooling a critical load of 200kW for 2 hours

  1. Assuming that the critical load is spread equally between the machine room and the vault,
    1. no air conditioning is required in the machine room to maintain temperature at an acceptable level (the temperature stays below 40°C for at least 110 minutes), but
    2. at least one air conditioning unit in the vault must be operational to maintain an acceptable temperature for up to 2 hours.
  2. There had been some concern that, even with the 30m3 buffer, the chilled water supply would not be enough to keep one air conditioning unit working for 2 hours. However, given that the chilled water is at 7°C and that the unit requires 18m3/hour, Jukka considers that the buffer is adequate.
  3. However, the critical load UPS would need to support the air conditioning unit and the chilled water pumps. This would increase the capacity required to 400kVA.

4.             AOB

  1. The following planning and meeting schedule was agreed
    1. 23rd September: meet to review initial substations plans prepared by Anne
    2. 7th October: review final substation plans
    3. 11th October: Tony presents overall planning at IT meeting leading to decision on required autonomy for the critical load UPS.