Ventilation of Genset Room

Source: genset.info

Ventilation of the genset room is necessary to provide combustion air to the engine, remove the heat emitted from the genset and any other equipment in the room, and to remove any fumes. To prevent recirculation the radiator must be placed near the room outlet air port, connected, and sealed by flexible ductwork.

NOTE: The phrase “genset room” and the term “room” are used throughout this post. However, the principles discussed here are applicable to any means of enclosing the genset. For the purposes of this section, consider “room” synonymous with “powerhouse,” “housing,” “container,” “enclosure,“ etc.

Poor ventilation system design and/or installation can lead to the following problems:

• Hazardous conditions for genset room personnel (if applicable)

• High temperatures around the set that can lead to poor performance and overheating

• Poor operation in cold climates if the installation permits exposure of the unit to cold temperatures

• Issues with other equipment in the room that may be sensitive to high or low temperature.

Requirements

• Engine exhaust manifolds and turbochargers shall not be insulated.

• Rigid insulation shall not be used on expansion joints.

• Heat from other sources shall be considered in the ventilation system design.

• Room inlet / outlet shall:

• Accommodate the total combustion and ventilation airflow through the room.

• Permit airflow across entire genset from alternator end to radiator end.

• Draw/discharge ventilation air directly from/to outdoors.

• Permit the required amount of fresh air flow across each set in a multiple set installation.

• The louver manufacturer shall be consulted for air velocity limits.

• Radiator discharge ducts shall be self–supporting.

• Ventilation system shall be designed for acceptable operation with all entry / service doors closed. All doors shall remain closed during genset operation to maintain the designed ventilation flow.

• The crankcase breather line shall be routed such that vapors will not foul equipment.

• If the crankcase breather is modified, crankcase pressure shall be measured at rated power. Pressure must be positive but not exceed 3 inches of water (0.75 kPa).

• For set–mounted radiator / fan packages, genset room total airflow restriction shall not exceed the maximum value listed on the Generator Set Data Sheet.

• Louvers shall open immediately upon genset start–up for emergency / standby installations. In cold climates, louvers may open partially for combustion air only and controlled to modulate the temperature in the room.

• If a blocking wall is installed, it shall be located no closer than a distance equal to 1X the discharge louver height away from the building. For optimal performance, the wall should be located approximately 3X the discharge louver height away from the building.

• A turning vane and drain shall be included with any blocking wall installation.

• If ventilation system filters are installed, a system for detecting plugged filters shall be in place.

Recommendations

• Exhaust piping and mufflers should be insulated.

• Maximum outdoor temperature should be measured near the air inlet.

• Air velocity should be limited to 500 – 700 feet/minute (150 – 220 meters/minute) to prevent rainwater / snow ingress. See above requirement regarding louver limits on air velocity.

• Room inlet / outlet location recommendations.

• Inlet should not be located near engine exhaust outlet.

• Inlet and outlet should not be located on the same wall.

• Outlet should be located as high as possible and inlet should be located as low as possible, while maintaining fresh air flow across the entire set.

• Outlet should be located on downwind side of the building.

• Additional combustion equipment should not be located in the genset room.