internal_id[1] = id_gt building type: 1: EFH, 2: ZFH, 3: MFH(3-6), 4: MFH(7-12) ,5: MFH(>12)
internal_id[2] = id_ba construction age class: 1: before 1900; 2: 1900 until 1945; 3: 1946 until 1960; 4: 1961 until 1970; 5: 1971 until 1980; 6: 1981 until 1985; 7: 1986 until 1995; 8: 1996 until 2000; 9: 2001 until 2005; 10: after 2006; 2012: 2012; 2013: 2013; 2014: 2014; 2015: 2015; 2016: 2016; 2017: 2017; 2018: 2018 internal_id[3] = heating structure (or energy carriers): 9: hardcoal; 10: brown coal; 11: natrual gas; 34: heating oil; 35: Biomass (solid); 68: ambient heat; 69: solar heat; 71: district heating; 72: electrical energy; 218: Biomass (excluding Wood, Biogas) internal_id[4] = Leerstand: 0 vacancy, 1 no vacancy