Energy recovery possibilities in natural ventilation of office buildings.

The paper deals with energy consumption and heat recovery in office buildings with natural ventilation. Net energy consumption for ventilation is calculated for 7 European countries. The calculations are done with various air flow rates and occupancy. The calculations shows differences between the seven countries, but the net ventilation heat loss is substantial for all. Norway and Sweden will benefit most from heat recovery. Several heat recovery concepts for natural ventilation are presented. Advantages and disadvantages with the various systems are discussed, also with respect to requirements as thermal comfort, air flow control, air cleaning and operation/maintenance. The paper also analyses the distribution of natural driving forces for ventilation both in various countries and in different parts of the heating season. The calculations indicate a ---need for assisting fans.