One perceived drawback of using chilled beams is the lack of 'free air cooling' in winter when the chilled water may not be available. Please advise me on what the effects are of supplying the fresh air to the active chilled beam at low temperature (say 12C or lower). Will the air distribution remain acceptable or will 'dumping' occur? Will the heater batteries be able to warm up the air in those rooms that don't need cooling?
There are several ways to implement free cooling with the beam system. One is to use cold outdoor air to cool down the supply air temperature / supply out door air directly to the beam system. When 12 deg. air is used, we first have to be sure, that the dew poin of room air in all the spaces is lower than that (no condensation in the duct / plenum surfaces). Another issue is the damping of the air. Due to fact that beam is a high induction unit, where induction rate is a. 1:4, we can use cold supply air if beam is not cooling, but supply air is mixed to the warm room air inside the beam,and the mixed air is in high enough temperature. Only problem is then, if in some rooms the cooling of supply air is not enough and there is a need of opening some valves. In those cases, the mixed air becomes very cold and damping occur.
There is another way of free cooling with beam system. The inlet water can be cooled down by circulating the return water in an air handling unit. The supply air warms in the same time when water cools down. This could be a safer way of free cooling in terms of comfort.
Source
Building Sustainable Design
