Plate heat exchangers have been widely used in dairy, food processing, paper/pulp, heating, ventilating, and other related industry. While single-phase flow in plate heat exchangers has been studied extensively, the industry lacks basic information on fluid flow evaporating in plate heat exchangers. This paper provides a review of heat transfer and pressure drop correlations for fluid flow evaporating in plate heat exchangers. Emphasis is placed on the application of a plate heat exchanger as an ammonia evaporator in a refrigeration system. It is shown via thorough research of related thermal–hydraulic phenomena that heat transfer and pressure drop correlations are needed for liquid ammonia flow evaporating in plate heat exchangers. The effects of plate geometry, plate material, oil/lubricant concentration, and several operating parameters on heat transfer coefficient and pressure drop for plate heat exchangers also need to be quantified.