Understanding the HVAC Mini Split Refrigeration Cycle in AC Mode with R-32 & R-410A

The HVAC mini split system is a popular choice for cooling and heating residential and commercial spaces. These systems utilize a refrigeration cycle to transfer heat from the indoor space to the outdoor environment. In this article, we will explore the refrigeration cycle in AC mode specifically for mini split systems using R-32 and R-410A refrigerants.

Refrigeration Cycle Overview

The refrigeration cycle in an HVAC mini split system consists of four main components: the compressor, condenser, expansion valve, and evaporator. These components work together to facilitate the heat transfer process and provide cooling to the indoor space.

  1. Compressor: The compressor is the heart of the refrigeration cycle. It is responsible for compressing the refrigerant gas, increasing its pressure and temperature. In AC mode, the compressor receives low-pressure, low-temperature refrigerant vapor from the evaporator.
  2. Condenser: The high-pressure, high-temperature refrigerant vapor from the compressor enters the condenser. The condenser is located in the outdoor unit and is responsible for releasing heat from the refrigerant to the outdoor environment. As the refrigerant cools down, it condenses into a high-pressure liquid.
  3. Expansion Valve: The high-pressure liquid refrigerant then passes through the expansion valve. The expansion valve is a small orifice that regulates the flow of refrigerant into the evaporator. As the refrigerant passes through the expansion valve, its pressure drops, causing it to expand rapidly. This expansion leads to a decrease in temperature.
  4. Evaporator: The low-pressure, low-temperature refrigerant enters the evaporator, which is located in the indoor unit. The evaporator absorbs heat from the indoor air, cooling it down. As the refrigerant evaporates, it changes from a liquid to a gas, absorbing heat energy in the process.


R-32 and R-410A R-32 and R-410A are commonly used refrigerants in HVAC mini split systems. These refrigerants have different properties and environmental impacts.

  1. R-32: R-32 is a single-component refrigerant with low global warming potential (GWP) and zero ozone depletion potential (ODP). It offers excellent energy efficiency and is considered environmentally friendly. R-32 is commonly used in newer mini split systems due to its superior performance and lower environmental impact.
  2. R-410A: R-410A is a blend of two hydrofluorocarbon (HFC) refrigerants, R-32 and R-125. It has replaced R-22, which is being phased out due to its high ozone depletion potential. R-410A has a higher GWP than R-32 but is still considered a more environmentally friendly option compared to older refrigerants.

Understanding the refrigeration cycle in AC mode is crucial for HVAC technicians working with mini split systems. The compressor, condenser, expansion valve, and evaporator work together to transfer heat from the indoor space to the outdoor environment, providing cooling. R-32 and R-410A are commonly used refrigerants in these systems, offering improved energy efficiency and reduced environmental impact. By familiarizing themselves with the refrigeration cycle and different refrigerants, technicians can effectively diagnose and troubleshoot issues, ensuring optimal performance and comfort for their customers.

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