Numerical study of air distribution in apartment premises using compact regenerative heat exchangers

Introduction. Civil buildings have ventilation problems associated with inadequate air exchange and high heat loss. One solution to these problems is the use of decentralized compact reversible ventilation units with an exhaust air heat recovery function. They are called stationary switching regenerative heat exchangers (SSRHE). SSRHE provide a high degree of energy saving with low air flows. When using SSRHE, the issue of the effectiveness of air exchange and air distribution in the room is important. Therefore, a study was conducted to assess the mobility of air in the premises of typical apartments when using such devices at various characteristic air flow rates.

Materials and methods. The CFD method of modelling the operation of mechanical supply and exhaust ventilation based on a compact regenerator in a two-room apartment is applied. The Ansys Fluent software package was used for modelling. The isothermal formulation of the problem is considered. The turbulence model is adopted by k–omega (k–ω). 

Results. The distribution fields of air velocity in the plan of rooms at different heights with different characteristic air flow rates are presented. An increase in indoor air mobility is shown with an increase in ventilation performance. The combined effect of mechanical decentralized ventilation and natural centralized exhaust ventilation of residential buildings is shown.

Conclusions. Based on the simulation results, it was determined that when using ventilation devices of the SSRHE type, it is possible to ensure the required air mobility in the premises, which contributes to effective air exchange. It is determined that the permissible indoor air mobility is set for air flow rates in the range of 50–100 m3/h. The results of the study can be used in the design of mechanical ventilation systems for residential multi-apartment buildings based on compact SSRHE-type installations, as well as in the combination of natural and mechanical ventilation. In the future, it is necessary to conduct a study of air distribution for other types of apartments, which will expand the database to develop recommendations and create a methodology for designing ventilation systems based on compact reversible devices. Experimental confirmation of the simulation is also required.

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