Modelling Life Cycle Cost for Indoor Climate Systems

Assumptions of productivity costs related to the outdoor supply airflow rate and indoor temperature can be made based on a number of recent studies. A life cycle cost (LCC) computer program for indoor climate systems based on Swedish conditions was developed and used to compare and optimize different indoor climate systems. A productivity cost related to the outdoor supply airflow rate and the indoor temperature according to the recent studies was assumed. A higher outdoor supply airflow rate, as well as a more correct indoor temperature, increases the energy use and in some cases the designed maximum power and thereby the initial cost of the indoor climate system, which includes the heating, ventilation and cooling systems. The results indicate that a much higher outdoor supply airflow rate at presence is appropriate from a life cycle cost perspective as well as a cooling system is, even if the influence on the human being still should be taken with precaution. With that higher airflow rate, the results show that there is a clear benefit with variable airflow rate ventilation systems due to the low reported occupancy level and the option, at absence, to lower the airflow rate a lot