The effect of nano-lubricant TiO2 in cooling system R134a on vapour compression cooling system. Periodicals of Engineering and Natural Sciences, [S. l.], v. 10, n. 1, p. 533–543, 2022. DOI: 10.21533/pen.v10.i1.557. Disponível em: https://pen.ius.edu.ba/index.php/pen/article/view/557. Acesso em: 19 may. 2026.