What is the function of heat exchangers in power systems?

Heat exchangers play a crucial role in power systems by facilitating the transfer of heat between two fluids without allowing them to mix. This process is essential in various applications, including cooling down hot fluids, heating up cold fluids, and even in steam generation processes.

In the context of power engineering, the primary function of a heat exchanger is to efficiently move thermal energy from one medium to another, which can help in maintaining desired temperatures within the system and optimizing energy use. For example, in a steam generator, water is heated by the combustion gases, but these gases and the water must remain separate to prevent contamination and ensure that the heat transfer is effective.

While cooling down hot fluids is a common function associated with heat exchangers, it is just one part of their overall operation. Similarly, creating steam is a specific outcome of the heat exchange process but does not encompass the fundamental role of these devices. Increasing fluid pressure, while necessary in certain applications, is not directly related to the functional purpose of heat exchangers, which focus primarily on heat transfer rather than changes in pressure. Thus, option C accurately captures the essence of what heat exchangers do in power systems.