Impacts of increased outdoor air flow rates on annual HVAC energy costs in office environment

Abstract

The use of different ventilation systems has an important impact on the energy cost of office buildings. This paper examines the relationship between heating and cooling load, and the associated energy consumption and energy costs with different HVAC system configurations. The influence of the HVAC system using economizer, heat exchanger or both, in CAV and VAV configuration, has been studied in five European cities, which represent the five main climates in Europe. Different heating sources have been examined as well. The free cooling concept analyze has been carried out, in concrete terms, in a classic office building. The results presented in this paper clearly indicate the advantage of the use of both economizer and heat exchanger over particular climate conditions. Optimization of the HVAC systems is performed by the choice in economizer control and ventilation system (CAV/VAV). Due to the economizer, cooling loads can be brought to zero in very cold and dry climate (Kiruna, Sweden) but it is also efficient in warmer climates such as Mediterranean climate contrary to the common wisdom.