In the paper three-dimensional case of heat transfer and air flow has been presented for enclosed space heating and cooling with unit mounted on the wall. Numerical modelling has been used to analyze effect of space height on temperature and air velocity distribution under standard conditions. Physical processes in two rooms with different heights are modelled using specialized computational fluid dynamics (CFD) software FLUENT. Calculations are carried out in an empty room without any human or mechanical activity and compared with previous experimental measurements. Numerical analysis has shown distinct relationship between room dimensions (height in this case) and state of comfort in the room. Although average values of temperature and air velocity in the room are satisfactory there are local distortions from the standard optimal comfort values. Considerable differences in temperature distribution are observed especially in heating conditions where temperature drop in lower layers of higher room occur due to buoyancy effects. To cancel buoyancy effects it is necessary to increase air inlet velocity from the unit which could lead to local air velocity distortions resulting with disturbed optimal comfort values.

Mechanical engineering,Other fundamental technical science