Sunday, October 3, 2010

Offshore Rig HVAC systems - general information

Offshore Rig HVAC System: - The purpose of air conditioning system is to provide a comfortable working and living environment for crew & personnel on board the semi or jackup rigs, and to maintain acceptable conditions for operation of electrical equipment in the switchboard room.

Mechanical: - The Air-conditioning system for Living Quarters and SCR Room could be a refrigerant direct expansion type or chilled water system. Quarters Air conditioning system consists of two Condensing Units- Seawater cooled type.  Three AHUs with direct expansion type cooling coils, serving accommodations respectively in Upper & Main deck, Tween & Lower deck (Port and Stbd). The AHUs could be provided with build-in heaters (3-steps control) and humidifiers to maintenance required room temperature and humidity.

The air conditioning system for SCR Room may consists of two Condensing Units-Seawater cooled type for direct expansion type coils, located in AHU room at Lower deck and operate only in cooling mode.

Condensing units for Air conditioning system and for SCR Room use R-134a Refrigerant, Window and Split conditioners use R22 however this refrigerant type will not be allowed by year 2020 and all existing units to be charged with new CFC free refrigerant. The quarter system is designed to maintain overpressure in passageways. Each cabin maybe equipped with reheater and room thermostat for individual temperature control depending on the area where the rig operates, usually you do not need them in the Gulf of Mexico except those north sea or colder climate.

Ventilation Fans are installed in the quarters to exhaust air from Galley Hood, Sanitary, Laundry, Change Rooms, Sick Bay & Clinic, Coffee Shop, Recreation Room, Fan Rooms and to supply fresh air to Galley and Fan Rooms. Classification requires galley AHU to be dedicated unit and not shared with other aircon spaces, cabin, public areas.

Rig Cold room and freezer System :- The purpose of the refrigeration systems are to cool down and maintain a reduced room temperature in the freezer room (-25 / -22 degC), cold room (-1 / +2 degC) and vegetable room (+8 / +11 degC) for preservation of foodstuffs. These store food rations for crew consumption onboard and usually these last for about 2-3weeks before they are replenish from supply vessels to the operating rigs.

Mechanical :- The refrigeration systems consist of three (3) evaporator units, one located in each of the freezer room, cold room and vegetable rooms, and two (2) condenser units, located in the fan room no. 1 on lower deck.
Piping :- R-404a refrigerant for the refrigeration systems is piped from each evaporating unit to the condensing units. The condensing units are seawater cooled using the vessel sea water service / cooling system.

HVAC Presentation1


suriya said...

Your excellent guidelines will be of great help to many. Nice post. I enjoyed reading it. Thanks!

Refrigeration Equipment

Choong Kim Whye said...

Thanks, you are welcome.