Why does decreasing evaporator airflow impact an air conditioner's performance?

[sevensages]

TL;DR

Why does lower evaporator airflow cause lower low pressure side Saturation temperature on an air-conditioner?

The other day I read on a website that a lower evaporator airflow causes lower low pressure side saturation temperatures and higher delta T on an air-conditioner. Now I think I know why a lower evaporator airflow would cause a high delta T. If there is less air moving over the evaporator, the evaporator would be able to cool the (small) amount of air that goes through the evaporator more quickly and effectively. But I cannot figure out why a lower evaporator airflow would cause the low pressure side saturation temperature to be lower.

Why does low evaporator airflow cause the low pressure side saturation temperature to be lower on an air-conditioner?

 

[Lnewqban]

Copied from:
https://hvacrschool.com/impacts-of-decreasing-evaporator-air-flow/

“What Happens When Airflow is Decreased?

In this theoretical system, when the airflow is decreased and all else stays the same, the following things will occur:

• Mass airflow will decrease, meaning fewer molecules are moving across the coil.
• Air velocity will decrease, meaning the air is moving over the fins and tubing more slowly.
• The bypass factor decreases; more air molecules will be touching the metal as a ratio.
• Air temperature decreases (to a point) due to the air moving more slowly across the coil with less bypass factor.
• Coil temperature decreases because less overall heat is being picked from the air.
• Coil drops further below the dewpoint, causing more moisture to be removed from the air, increasing dehumidification.
• Suction pressure decreases because less heat energy being picked up means less pressure, and as the superheat falls, the TXV also further throttles the flow of refrigerant through the coil.
• The compression ratio increases as the suction pressure drops, meaning the compressor moves less refrigerant as the refrigerant density entering the compressor falls.
• Coil TD increases as indicated by the colder coil in relation to the return air.”