HFC-134a, which is currently widely used as a refrigerant in automotive air conditioners, has a high GWP (Global Warming Potential) of 1,430.

On the other hand, HFO-1234yf (GWP=4) has a much lower GWP compared to HFC-134a; thus the switch to HFO-1234yf is underway to prevent global warming.

However, the cooling efficiency of HFO-1234fy is lower than that of HFC-134a.

In order to compensate for this lower cooling efficiency, we have developed IHX.

The IHX is made of a double tube by integrating parts of 2 refrigerant pipes, which were originally constructed separately.

Internal heat exchange using the temperature difference between the high temperature refrigerant and low temperature refrigerant helps to improve the cooling efficiency of the entire air conditioning system.(figure 1)

Also since the automotive air conditioning system is arranged in a small space in the engine room, the piping design must be made according to the layout of the engine room.

The IHX, however, has a fin arranged inside which will prevent the flow path of the refrigerant from being stopped even when the IHX is bent. (figure 2)

This enables the piping to be designed as freely as the conventional air conditioning system.

Figure 1: Image of automotive air conditioning system using IHX

Figure 2: Cross-sectional view of IHX with fins