CASE STUDY | LSE NATURAL VENTILATION team was helped by the amazing historical occupancy data for each department supplied by LSEs Estates team. This confirmed that academics tend to work late into the evening and are absent for much of the summer. It was such random occupancy that we decided to control the natural ventilation by enabling the BMS to kick in and open the windows when people are not occupying a space, says Vereenooghe. Each bay of the aluminium-framed, glazed faade incorporates openings to facilitate natural ventilation. Actuator-controlled top-lights open and close under control oftheBMSto give daytime ventilation and night-time heat purge, while large, inward- Open plan Environmental design features Outdoor comfort Flexibility and adaptability Natural ventilation Daylight penetration Solar control (shading design) Atrium design and ventilation Green roof Rainwater management Section drawing of thebuilding Open plan Cellular office Section showing spatial arrangement (open-plan or cellular) and effect of natural ventilation CIBSE overheating scale Pass Margin Fail opening, occupant-controlled, low-level, sidehinged, windows give occupants the option to boost ventilation. Ultimately, the success of the natural ventilation solution in delivering comfort will rely on: the occupants interaction with controls; acceptance of increased external noise; air quality; and being able to achieve acceptable levels of air movement that will avoid papers being blown from desks, for example. The building is under user control when it is occupied, Vereenooghe explains. Mechanical ventilation supplies fresh air and cooling to the lower floors. The plantroom, at Basement Level 1, houses the majority of the buildings MEP plant, while a smaller plant space at Basement Level 2 houses rainwater attenuation and harvesting tanks, along with sprinkler tanks and associated pumps. Basement Level 1 also incorporates a large auditorium, bar area and breakout space. Seven air handling units (AHUs) some serving individual lecture theatres and other more general spaces, such as the groundfloor cafe and reception are housed in the Basement Level 1 plantroom. The main freshair intake is on the buildings south elevation; air enters through a louvred opening and then passes down a shaft to the basement, where it feeds an AHU supply plenum running along the west side of the basement plantroom. Air is discharged from the AHUs into a similar plenum running above the supply-air plenum, before passing out in RSHP style through two expressed exhaust-air trumpets in the plaza, and a louvred opening in the south elevation. Evaporative humidifiers in the air handling plant, in conjunction with heat pipes, thermal wheels and chilled water coils, provide cooling in the AHUs. The wrap-around heat pipe consists of two sections: the precool (evaporator) section, placed before the cooling coil, and the reheat (condenser section), placed after the reheat coil. The pre-cool section is located in the incoming air stream before the cooling coil. When warm air passes over the pre-cool section, the liquid refrigerant vaporises, moving heat to the reheat section, downstream The new LSE building is designed to beunderuser control when it is occupied 32 June 2019 www.cibsejournal.com CIBSE Jun19 pp30-33 LSE.indd 32 24/05/2019 18:58