What is a Heat Exchanger and How Does is Work?

December 20, 2021
Broken Heat Exchanger in Hayden, ID

A heat exchanger is a device that transfers thermal energy from one fluid to another. It can be used in both heating and cooling processes, depending on what kind of fluid it’s transferring heat between. Refrigerators and air conditioners, for example, use heat exchangers in the opposite way from central heating: they remove heat from a room and dump it away. The main goal of a heat exchanger is to provide efficient transfer of thermal energy by maximizing the contact area within the device while minimizing flow resistance. Below we discuss types of heat exchangers and how they work.

Plate and Frame Exchangers

Plate and frame exchangers are the simplest of all heat exchanger designs. They consist of metal plates with holes drilled through them to allow fluid flow. The design allows for a high surface area, which leads to excellent thermal performance at low-pressure drops. However, they don’t work well at elevated temperatures because the gaskets used around the drillings will fail over time due to thermal cycling.

Shell and Tube Exchangers

Shell and tube exchangers have tubes within other tubes, often called “double wall” or “triple expansion”. Fluids pass inside of these closely spaced tubing walls, where they exchange energy via conduction. This design can handle higher temperatures and pressures than plate-and-frame exchangers, but the flow resistance is usually much larger.

Brazed Aluminum Common Headers

Brazed aluminum common headers are used for heat transfer between fluids that solidify at low temperatures. The fluid enters through tubes in the header before reaching a set of fins to increase surface area and conductivity.

Brazed aluminum common headers are a popular choice when you need to transfer energy from one fluid to another in an indirect way. In this case, tubes made of either copper or aluminum connect each side directly by using brazing techniques that attach two separate pieces, along with a third piece, where they intersect, which acts as a “header” for both sides.

At Border Sheet Metal & Heating in Hayden, we provide professional heating maintenance, repair, and installation services to both commercial and residential clients. Call us today so that we can keep your heating and cooling systems working efficiently.

company icon