Is it harder for high-performance air conditioners to dehumidify?

Recently, I had the opportunity to exchange ideas at the headquarters of a certain air conditioner manufacturer. We exchanged a lot of useful information, and I would like to introduce one of them.

As we all know, newer and more expensive air conditioners tend to be deeper. This is the result of increasing the surface area that the air hits in order to improve efficiency. The amount of heat that air can transport is determined by the temperature difference x air volume. Air volume is proportional to the power consumption of the fan. Temperature difference is determined by compressors, etc. When moving the same amount of heat, it is overwhelmingly more energy efficient to use air volume. For this reason, it seems that the newer and more expensive air conditioners are more dependent on air volume.

　In the case of cooling, if the airflow can be increased, the temperature difference can be small. In other words, the refrigerant temperature inside does not need to be lowered that much. The amount of dehumidification is determined by the amount of condensation that can be produced. Therefore, if the refrigerant temperature does not drop, the amount of dehumidification will decrease. This happens even when air conditioners are upgraded to high performance, but on top of that, modern homes are highly insulated, so the amount of heat entering through the walls and roof is reduced. Furthermore, skilled designers can also block sunlight. In this case, the amount of heat that needs to be removed, i.e. the sensible heat load, is too small. In that case, the air conditioner does not have to work so hard.

This also means that the refrigerant temperature does not need to be lowered as much. This is something we have noticed and pointed out for some time. This is why it is important to cover a wide area with a small number of air conditioners in order to effectively dehumidify. Honestly, this is the only item I can think of that gets worse the better the design. This is why we can say that the reheat dehumidification function, in order to compensate for this, has become even more important than before. 　

However, most manufacturers are now withdrawing from reheat dehumidification. The main reason is likely to be the high manufacturing costs. I think this is a sad reality, as I don't think that manufacturers who are serious about their products will abandon reheat dehumidification.