In the Middle East, due to high external ambient temperatures and local building practices, we are faced with high internal heat gains. Whilst many engineers would be interested in more novel cooling solutions, there is little confidence in non-fcu/vav solutions. Please could you advise the maximum recommended load which your chilled beams and displacement ventilation systems can cope with ?
The chilled beam system can cope the loads up to 100 W/m2 without problems in comfort. You can get cooling output up to 150 W/m2 or even higher with a beam system but when ever the loads are higher than 100 W/m2, the velocity in the occupied zone increases above 0,25 m/s in a typical office installation (room height a. 2,7 m, distance between the beams is a. 3 m).

So if the beams are used in the spaces with high heat loads, the special attention should be payed to avoid draught problems in the occupied zone.

In hot and humid conditions the designers shoul pay a special attention to the risk of condensation. The supply air must be dehumidified so that the room air dew point in all conditions is lower than inlet water temperature.

The risk is highest in the early morning when ventilation has been shut off during the night and building might be full of humid air. This is why the ventilation system should be switched on before the cold water starts to run in the pipe work. It is also recommended to pressurise the building slightly to avoid infiltration of humid outdoor air through the building structures.

With displacement ventilation system the highest cooling out put in relatively low spaces (<4 m) is a. 40 W/m2. Higher cooling requirement increses the primary air flow rates to be much higher than with traditional mixing systems.