Novel coolant with low electrical conductivity

A coolant concentrate, comprising:

• (A) 1,2-propylene glycol or derivatives thereof:
• 50 to 99.9 wt %,
• (B) water:
• 0 to 10 wt %,
• (C) at least one azole derivative:
• 0.02 to 1 wt %,
• (D) optionally at least one ester of orthosilicic acid or alkoxy alkylsilane:
• if present 0.02 to 1 wt %,
• (G) at least one silicophosphonate:
• 0 to 1 wt %, and
• (H) optionally at least one further coolant additive:
• 0 to 0.5 wt % for each further coolant additive, with the proviso that the sum of all components always add up to 100 wt %.

A method of cooling in systems comprising a heat exchanger comprising aluminum components, the method comprising:

• circulating a coolant within said systems, wherein the coolant comprises:
• (A) at least one 1,2-propylene glycol or derivatives thereof,
• (B) water,
• (C) at least one azole derivative,
• (D) optionally at least one ester of orthosilicic acid or alkoxy alkylsilane,
• (G) optionally at least one silicophosphonate, and
• (H) optionally at least one further coolant additive,
• wherein at least one of the components (D) and (G) is present, and
• wherein the electrical conductivity is at most 50 μS/cm.