Plate Heat Exchanger

The domestic heating industry has rapidly adopted the use of plate heat exchanger in recent years, particularly in the production of combination boilers. However, most plumbers generally do not know about their operation and application, even though their use would be highly beneficial in numerous instances.

Let’s begin by defining what a plate heat exchanger is. Quite simply, one uses the device to transfer heat from one liquid (or gas) to another. Most plumbers understand the principle of a coiled heat exchanger, which standard domestic indirect hot water cylinders use to transfer heat from primary water to the stored domestic water. The coil transfers heat through its wall to the stationary water within the cylinder as hot water from the boiler flows through it.

A plate heat exchanger transfers heat by hot water flowing in one direction (primary) through the heat exchanger to cold water flowing in the opposite direction (secondary). Numerous stainless steel plates conduct the heat to keep the two sets of water separate. Typically, waterways can operate up to 10 bar pressure, although manufacturers offer models that can handle far higher pressures.

The temperature difference between the two water flows and the flow rates increase the rate at which heat transfers. A plate heat exchanger measuring only 20 x 7 x 12cm can transfer heat at over 100kW, which can heat 45 litres per minute of hot water from 12°C to 42°C. The plate heat exchanger’s high efficiency and small size make it perfect for a wide range of applications.