An Air-Cooled Chiller is a refrigeration system that removes heat from a liquid (usually water or glycol) using air to cool the condenser instead of water.
A Water-Cooled Chiller is a refrigeration system that removes heat from a liquid using water circulated through a condenser to absorb and carry away the heat.
An Absorption Chiller is a cooling system that uses heat energy (instead of electricity) to drive a refrigeration cycle, typically using a refrigerant and absorbent pair like water and lithium bromide.
An Evaporative Chiller is a cooling system that lowers water or liquid temperature by evaporating a portion of it, using the latent heat of vaporization to absorb heat.