Reduced heat flow in light water (H2O) due to heavy water (D2O)

TL;DR

Adding small amounts of heavy water (D2O) to light water significantly reduces heat flow, extending cooling times dramatically, with the effect depending on concentration and requiring no mixing after addition.

Contribution

This study demonstrates a novel method to control heat transfer in water using heavy water, revealing a concentration-dependent effect that was previously unreported.

Findings

Heat flow decreases by over 1000% with D2O addition.

Cooling time extends from 11 hours to over 100 hours with D2O.

Effect depends on D2O concentration and disappears if water is mixed after addition.

Abstract

The flow of heat, from top to bottom, in a column of light water can be decreased by over 1000% with the addition of heavy water. A column of light water cools from 25 C to 0 C in 11 hours, however, with the addition of heavy water it takes more than 100 hours. There is a concentration dependence where the cooling time increases as the concentration of added (D2O) increases, with a near maximum being reached with as little as 2% of (D2O) added. This phenomenon will not occur if the water is mixed after the heavy water is added.