LIFE CYCLE COSTS FOR INDOOR CLIMATE SYSTEMS WITH REGARDS TO SYSTEM CHOICE, AIRFLOW RATE AND PRODUCTIVITY IN OFFICES

Assumptions of productivity costs related to the outdoor supply airflow rate and indoor temperature canbe made based on a number of recent studies. A life cycle cost (LCC) computer program for indoorclimate systems based on Swedish conditions was developed and used to compare and optimizedifferent indoor climate systems. A productivity cost related to the outdoor supply airflow rate and theindoor 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 thedesigned maximum power and thereby the initial cost of the indoor climate system, which includes theheating, ventilation and cooling systems. The results indicate that a much higher outdoor supply airflowrate at presence is appropriate from a life cycle cost perspective as well as a cooling system is, even ifthe influence on the human being still should be taken with precaution. With that higher airflow rate, theresults show that there is a clear benefit with variable airflow rate ventilation systems due to the lowreported occupancy level and the option, at absence, to lower the airflow rate a lot.