The plate heat exchanger consists of a set of metal plates with four corner holes for the passage of both hot and cold media.When the heat trasnfer plates are stacked together, the holes in the corners of the sheet form a continuous passage or conduit that allows the medium to enter the stack from the inlet and distribute it into the narrow passage of the heating plates. Because the arrangement of the gaskets on the plates and the plates are alternately arranged in A and B plates, the two media alternately enter the narrow channels. For example, the heat medium is between the odd channels and the cold medium is between the even channels, so that the plates separate the two media. In most cases, the media flows in the opposite direction. During the flow through the device, the hotter medium imparts a certain amount of thermal energy to the sheet, which immediately releases the heat and passes it to the colder medium on the other side. The hotter medium has a lower temperature, while the cooler medium has a higher temperature.