Improving PAQ and comfort conditions in Spanish office buildings with passive climate control

Abstract Some researchers have demonstrated that passive moisture transfer between indoor air and hygroscopic structures has the potential to moderate variations of indoor air relative humidity and, thus, to improve comfort and PAQ [Simonson CJ, Salonvaara M, Ojalen T. The effect of structures on indoor humidity-possibility to improve comfort and perceived air quality. Indoor Air 2002; 12: 243–51; Simonson CJ, Salonvaara M, Ojalen T. Improving indoor climate and comfort with wooden structures. Espoo 2001. Technical Research Centre of Finland, VTT Publications 431.200p+app 91p]. The main objective of this study is to show the internal wall coating effect on indoor air conditions and, as a consequence of this, in comfort conditions and PAQ. In a previous paper [Orosa JA, Baalina A. Passive climate control in Spanish office buildings for long periods of time. Building and Environment 2008], we analysed the influence of permeable and impermeable materials on indoor air conditions, during the unoccupied period, in 25 office buildings in different seasons. Results obtained lead us to conclude that real coverings such as permeable, semi-permeable and impermeable types, present different behavioural patterns in indoor air conditions. Furthermore, we concluded that an absorbent structure will moderate relative humidity indoors. In this paper, we study this indoor relative humidity effect on local thermal discomfort, due to decreased respiratory cooling, and indoor ambience acceptability for the early hours of morning applying PD and Acc models [Toftum J, Jorgensen AS, Fanger PO. Upper limits for indoor air humidity to avoid uncomfortably humid skin. Energy and buildings 1998; 28: 1–13; Toftum J, Jorgensen AS, Fanger PO. Upper limits of air humidity for preventing warm respiratory discomfort. Energy and Buildings 1998; 28: 15–23] such as that proposed by Simonson et al. [The effect of structures on indoor humidity-possibility to improve comfort and perceived air quality. Indoor Air 2002; 12: 243–251]. Results showed that hygroscopic structures have the potential to improve local thermal comfort and especially PAQ in the first hours of occupation and that relative influence of humidity on acceptability was higher than on thermal sensation. These conclusions would, with a more intelligent design, give energy saving and improve comfort and PAQ.