Project Details
Value in SR

Project Description
THE CHILLER PLANT, the LARGEST DIRECT AIR COOLED SYSTEM IN THE WORLD has a total capacity of 21,000 tons supplied by 6 York centrifugal chillers, each with a capacity of 3,500 tons and driven by 7,000 HP, 13.8 KV, totally enclosed, water to air cooled motors .

Scope of Work

  • Bemco mechanical scope covered detailed engineering studies and coordination with the manufacturers - as every major item was custom made. The refrigerant piping was computer-analyzed for load conditions, stress levels and displacement at each support. This is followed by procurement, installation, testing and commissioning.
  • Each chiller is provided with dedicated primary pump with a capacity of 3,500 GPM and driven by 250 HP, 4160 V TEFC motor and a seventh standby pump.
  • The chilled water system is a variable flow. Primary-Secondary pumping system with the Primary pumps located inside the chiller plant and the Secondary distribution pumps located inside the Mosque pump room.
  • A 7 km. underground tunnel carries the chilled water at 42 deg.F. (5.6 deg.C.) through 36" diameter pre-insulated pipes from the chiller plant to the Mosque Secondary pumps, which distributes the chilled water on the 144 AHU's located in the Mosque basement.
  • After the pressure test (dry nitrogen 334 Psig), each system was then evacuated to less than 1,000 micron, measured by a high vacuum electronic thermocouple gauge and only then charged with R-12 refrigerant.
  • Each chiller is provided with its local automatic control panel with gauges and annunciators. A BACS panel, transmits this information to a central control room for remote monitoring of the chiller plant.
  • A separate 600 Ton "Emergency" Chilled Water System was installed to supply chilled water to the main chiller auxiliaries during initial and/or warm water start-up of the main chillers. The system is also connected to the standby power plant to cool the critical rooms in case of main power failure.

Other systems:

  • Compressed air system for plant instrumentation.
  • Halon fire protection system for electrical rooms.
  • Chemical feed systems for corrosion protection of the chilled water system.
  • Drainage Pumping systems.
  • A wetpipe hose rack for fire protection of the main plant areas.
  • A 20 MW standby power plant.
  • A BACS system to monitor all the equipment inside the plant complex.
Madinah, Saudi Arabia
225 Millions
Ministry of Finance
1986 to 1991