Abstract: Oil cooling is accomplished in a refrigeration chiller by flowing hot oil into heat exchange contact with liquid refrigerant which is sourced from the chiller's condenser and returned thereto. The rejection of heat from the oil to the refrigerant in an oil-cooling heat exchanger causes vaporization of the refrigerant and, in turn, creates a density difference in the refrigerant flowing from the condenser and refrigerant in and downstream of the oil-cooling heat exchanger. This density difference is responsible for inducing and maintaining refrigerant flow through the heat exchanger for oil cooling purposes.