How to Choose Condensing Units and Its Size?

In this article, you can see what it is, what it is used for, and the benefits of a Condensing Unit (CU). Now, let's talk about the key points to consider when deciding which CU is best for each application.

1- Available space

Researching and analyzing the available space is a very important point in choosing a condensing unit. Many CUs are based on metal plates or "rails" and their dimensions are not standard in all cases, although the goal is always to seek standardization.

Another focus on physical space is the compressor range. Compressor heights vary from home to home, so care must be taken not to have problems when assembling.

Air Cooled Piston Condensing Unit         

2 - What is the capacity of the condensing unit?

For example, Embraco condensing units are designed by engineers who specialize in refrigeration. Each CU group ("compressor + condenser") is therefore appropriately sized to ensure technical reliability for the customer.

Thanks to dimensional accuracy, you can select a unit according to the capacity of the compressor development.

This capability depends on the operating points, such as temperature, evaporation, and condensation, as we will see in more detail in the next step.

3 - Simultaneous selection of the CU application

The condensing unit needs to be selected according to the application, e.g. refrigerated cabinets and beverage fridges. One of the main items is the evaporation temperature required in the cooling system, which depends on the "application range" (evaporation) for which the compressor is approved and ready to work.

The evaporation range of each compressor, and therefore the evaporation range of each condensing unit, varies. Therefore, when selecting a CU, always check the evaporation range in which the compressor is allowed to operate. This can be assessed using the technical data sheets. You can select the product and view this important information here. 

If it is necessary to apply the UC with a fluid different from that used in the previous system, it must be checked that the operating pressures (evaporation and condensation) are within the safety thresholds of the system piping.

 Copeland Air-Cooled Scroll Type Condensing Unit (5～15℃)

4 - Power supply and start-up torque

In addition to the discussion above, continue to focus on the power supply. Always choose a condensing unit with the same voltage and frequency as the power supply.

Start-up torque should also be analyzed. In systems with expansion valves (rather than capillary tubes), you must pay attention to whether the compressor in the condensing unit has a high starting torque.

For example, a compressor with a low starting torque is only suitable for systems with capillary tubes, a compressor with a high starting torque can be suitable for expansion valves and capillary tubes.

Have you taken these steps into consideration when selecting and sizing your condensing unit?