An experimental study of novel nanofluids based on deep eutectic solvents (DESs) by Choline chloride and ethylene glycol

•Binary and ternary DESs by Choline Chloride-Ethylene Glycol formed in 1:2 and 1:5 M ratios.•New stable MgO nanofluids based on the designed binary and ternary DESs.•Stability, thermal conductivity and density analysis of all samples performed.•Isobaric thermal expansivities was determined using experimental density values.•The maximum TC enhancement was 23% for 10 wt% MgO in DES A.