What is the primary function of a heat exchanger?

The primary function of a heat exchanger is to transfer heat between two or more fluids. This device is designed to efficiently facilitate the exchange of thermal energy without allowing the fluids to mix, which is crucial in many engineering applications.

Heat exchangers are utilized in various systems, such as heating, ventilation, and air conditioning (HVAC), refrigeration, and chemical processing, among others. By transferring heat from one fluid to another, heat exchangers can either heat a fluid or cool it, depending on the application.

In contrast, generating electricity from heat, cooling material down to room temperature, or storing thermal energy represent different thermal management processes but are not the primary function of a heat exchanger. The key feature of heat exchangers is their ability to manage and transfer thermal energy efficiently, making option B the correct answer.