N2 - Controlling low-temperature drying facilities which utilise nonprepared air is quite difficult, due to very large variability of ventilation air parameters - both in daily and seasonal cycles. The paper defines the concept of cumulative drying potential of ventilation air and presents experimental evidence that there is a relation between this parameter and condition of the dried matter (sewage sludge). Knowledge on current dry mass content in the dried matter (sewage sludge) provides new possibilities for controlling such systems. Experimental data analysed in the paper was collected in early 2012 during operation of a test solar drying facility in a sewage treatment plant in BÅ‚onie near Warsaw, Poland. L1 - http://journals.pan.pl/Content/94458/PDF/02_paper.pdf L2 - http://journals.pan.pl/Content/94458 PY - 2013 IS - No 4 December EP - 34 DO - 10.2478/aoter-2013-0027 KW - Sewage sludge drying KW - Solar drying KW - Dry matter calculation A1 - Krawczyk, Piotr PB - The Committee of Thermodynamics and Combustion of the Polish Academy of Sciences and The Institute of Fluid-Flow Machinery Polish Academy of Sciences DA - 2013 T1 - Cumulative ventilation air drying potential as an indication of dry mass content in wastewater sludge in a thin-layer solar drying facility SP - 23 UR - http://journals.pan.pl/dlibra/publication/edition/94458 T2 - Archives of Thermodynamics