Natural and Mechanical Ventilation

 

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Scope of analysis

The study has focused on the summer performance (June) of the main learning resource areas on the ground, first and second floors on the north side of the building.

A computer model of the relevant parts of the building has been created to provide for dynamic thermal simulation of the basic design and variants thereof.

It is proposed that control of summer temperatures is achieved using mechanical ventilation via a Termodeck hollow core ceiling slab system. Night time ventilation is intended to cool the structure, offering reduced fabric temperatures, and also slightly cool incoming outside air. A raised floor sits above the Termodeck slabs. Air is brought into the spaces via the Termodeck at ceiling level and via the Termodeck and raised floor at low level.

Day time air flow into each space is 2 m3/s. Night time air flow is 6 m3/s. A limit has been set on night time air flow to prevent resultant temperatures in the space being below 19oC at start of occupation.

 Click Here to download a study of peak summer performance. (109Kb)

Above, frequency distributions showing the number of hours for which given air and resultant temperatures are predicted to occur on the first floor learning resource area with computer heat gains reduced from 40 to 20 W/m2 on the base model.

Options

the following variations on the basic model have been evaluated:

  • increase wall insulation from 100 mm to 200 mm
  • triple glazing on north elevation, with and without blinds
  • reducing computer heat gains from 40 W/m2 to 20 W/m2.