Inverter condensing units

General information

A characteristic feature of condensing units equipped with inverter technology is capacity modulation, resulting in the ability to generate adequate cooling performance adapted to the needs of the installation. Unlike standard on-off and mechanical capacity modulation solutions, inverter technology allows a significant energy consumption reduction.

With the ability to modulate capacity, the quantity of compressor’s start and stop cycles is decreased. It also increases the compressor’s durability and minimizes the evaporators’ icing, which significantly decreases the overall energy consumption by reducing the amount of required defrost cycles.

Therefore, inverter condensing units feature significantly higher energy efficiency than standard on-off units, in which the compressor operates at only two speeds: 100% (the unit runs at full nominal power) or 0% (the unit is turned off).

Field results show that condensing units with inverter technology consume ~35% less electric energy than on-off units and provide more precise temperature regulation.

Each iCOOLTM CO2 and iCOOLTM HFC condensing unit is based on inverter technology.

Inverter technology – the principle of operation

The inverter technology system consists of four main components: low-pressure transducer, PLC controller, frequency inverter, and inverter compressor.

image of inverter technology elements

Fig. Main elements of the inverter technology.

Low-pressure transducer

It measures the pressure on the suction line and converts it to a signal transmitted to the controller. The suction pressure rises with the rise of the temperature inside a cooling cabinet or chamber. It is a signal for the compressor to increase the rotation speed and answer the cooling demand.

PLC controller

The controller is connected to the inverter via cable and provides information on whether the compressor should speed up or slow down. The controller also regulates the condensation pressure by controlling the fan’s speed based on the signal from the high-pressure transducer. The PLC controller is pre-configured and includes the system management software.

Important note: in some generations of the inverter condensing units, the PLC controller is built into the frequency inverter.

Frequency inverter

The primary function of the inverter is to change the compressor’s capacity by controlling its rotation speed. It cooperates with a PLC controller, which is based on the signal from the low-pressure transducer on the suction line. The inverter speeds up or slows down the compressor motor based on the cooling demand of the installation.

Inverter compressor

The most common type of inverter compressor is a hermetic scroll or rotary. It compresses low-pressure, low-temperature gas, which exits the liquid separator on the suction line. The frequency inverter regulates the compressor speed (and power consumption).

The cooperation of these four main components is presented in the visualization:

The main benefits of inverter technology

With the rapid increase in energy costs, the refrigeration sector needs energy-efficient solutions. One of the crucial advantages of the inverter solution is lower energy consumption.

The infographic shows the potential savings by using inverter condensing units instead of standard on-off condensing units in the commercial sector:

Energy savings infographic

For more information, see this article.

Inverter technology increases the compressor’s lifetime by reducing the number of start-stop cycles. It also enables the soft start of the compressor and reduces evaporators’ icing. The inverter solution provides direct control of pressure and temperature and the possibility to adjust the speed regulation method based on the application. Inverters can work both with AC and BLDC compressors. Moreover, inverter technology ensures the better quality of the stored products, with less drying and improved freshness.

Lower energy consumption Reduced evaporator icing Capacity modulation
Increased compressor durability Constant pressure and temperature control Ability to work both with AC and BLDC compressors

Tab. Benefits of the inverter technology.

Summary

Compared to the standard on-off units, inverter condensing units ensure significant energy cost reductions and increased reliability. Thanks to the more precise temperature regulation, inverter units provide the improved quality of the stored products.

iCOOLTM HFC and iCOOLTM CO2 are examples of inverter condensing units. These units are equipped with a frequency inverter and an appropriate advanced automation control system, allowing the smooth control of the unit’s performance. Moreover, the remote control enables real-time recordings and parametrization. These highly efficient, energy-saving, low-weight, low-noise, and well-equipped Plug&Play products are designed to work at ambient temperatures up to 43 Celsius degrees.

iCOOLTM units are a perfect choice for commercial cooling systems.

Check out what you have learned

Drag the component name and drop it on the proper description.

  • Suction line
  • Low-pressure transducer
  • PLC controller
  • Frequency inverter
  • Inverter compressor

  • It receives a signal from the low-pressure transducer and passes it to the inverter. It can be built into inverter or mounted separately
  • It operates with the inverter and its main function is to compress the low temperature and low-pressure refrigerant gas. Most often it is scroll or rotary type
  • It is used for rotation speed regulation of the compressor to adjust the current capacity, reduce the energy consumption and quantity of compressor’s start-stop cycles
  • Pipeline at the inlet of the condensing unit through which superheated refrigerant vapors at low temperature and low-pressure are sucked in by the compressor
  • A component which measures the pressure on the suction line and converts it into a signal that is then transmitted to the controller or directly to the frequency inverter

Well Done!

Component Description
Suction line Pipeline at the inlet of the condensing unit through which
superheated refrigerant vapors at low temperature and low-pressure
are sucked in by the compressor
Low-pressure transducer A component which measures the pressure on the suction line and
converts it into a signal that is then transmitted to the controller
or directly to the frequency inverter
PLC controller It receives a signal from the low-pressure transducer and passes it
to the inverter. It can be built into the inverter or mounted
separately
Frequency inverter It is used for rotation speed regulation of the compressor to adjust
the current capacity, reduce the energy consumption and quantity of
compressor’s start-stop cycles
Inverter compressor It operates with the inverter and its main function is to compress
the low temperature and low-pressure refrigerant gas. Most often it
is scroll or rotary type

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