Carrier Context:
Unique Projects


  Environmental Controls :
  Ensuring A Brilliant Future

Since there are better things to look at within the chapel, the 92 sensors (40 of them for redundancy's sake) that continually monitor air temperature, dewpoint and wall and ceiling surface temperatures are virtually invisible. The 26 kilometers of control wiring connecting the sensors to the system's computer-based controls also are hard to detect.

Two computer terminals, one sitting on a table in the Vatican's power station a five-minute walk away and the other residing with the Vatican's restoration scientists, merely allow humans to "talk" to the system and get information from it. The actual orchestration of the air conditioning system's separate elements, based on information being received from the sensors, is handled by microprocessor-based electronic controls distributed throughout the system.

If sensors in the chapel indicate the humidity is rising during a tourist-filled Roman summer day, the electronic control for the air handling unit determines that moisture must be removed from the air by cooling it, since cooler air carries less moisture.

That control signals its counterpart near a Carrier water chiller, located two floors below the chapel, to begin producing cold water. Other controls on the circuit open valves and start pumps that send the water through pipes on the outside of the chapel's south wall to the air-handling unit manufactured by Carrier S.A. in France. Outdoor air pulled into the air handler passes over pipes containing the cold water and is dehumidified. The temperature of the dehumidified air is then readjusted to the proper setting by an independent control circuit.

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