This is the first in a series of articles about battery power and its adjacent industries and processes.

Today, energy comes from a wide range of sources. The share of that collective power that comes from renewable energy sources continues to grow. In fact, in 2019, it was estimated that just under 20% of electricity generated at utility-scale electricity generation facilities in the United States was from renewable energy sources.[1]

Last month’s deadly cold spell in Texas and other areas of the South led to loss of power, water quality concerns for millions, and tragically, loss of life. Abnormal temperatures pushed all manner of equipment past its breaking point, and HVAC systems were hit hard.

As far as stages go, the big game is one of the biggest out there, and there’s a small army responsible for making sure the game goes off without a hitch. Behind that army of personnel is an even larger assemblage of vehicles, equipment, and other technology that help along the way – one of which is the heat exchanger.

There are a number of industrial processes that require extremely cold temperatures – sometimes as cold as -150°F. For the equipment used in such applications, those low temperatures pose some unique challenges. In this post, we’ll detail some of the temperatures involved and outline some things to consider with regard to heat exchanger design and materials for low-temp applications. 

Cooling data center IT equipment using air has been the industry standard for as long as there's been a data center industry. However, advances in computing technology have pushed the limits of what air-cooled systems are able to efficiently keep cool, as the amount of power needed to operate those systems increases. 

When designing a heat exchanger, an engineer should not only consider thermal performance, but also external influences that can negatively impact thermal performance, such as fouling.

In a refrigeration circuit, the evaporator coil plays a critical role. Part of its responsibility is creating the controlled pressure drop necessary for the refrigerant to change phase, the bulk of which occurs via the system’s metering device, such as a thermostatic expansion valve (TXV).

For low-temperature hydronic systems, systems in which chillers and AHUs are located outdoors, or other equipment used in low-temperature processes, some form of glycol is a critical ingredient. It works to lower the fluid’s freezing temperature, enabling lower-temperature operation and preventing freezing.

There are terrific braze joints, awful braze joints, and everything in between. Today, we’ll examine one type of defect that can have devastating effects on joint integrity – flux entrapment.

This article has been updated. It is accurate as of 9/23/20.

Heat exchangers used for different applications need different design features. For example, in industries like pulp and paper, lower fins per inch (FPI) are often included to reduce airside fouling and to make for easier cleaning. Other applications such as the military are often concerned with weight, which impacts material selection. For this post, we're going to focus on some unique design choices we often include when building heat exchangers for the refrigerated storage of potatoes, onions, beets and other vegetables.