Traditionally, indoor condition is characterized by the psychrometric chart which is independent of the abilities of an
air-conditioning unit. In present paper, the cooling and dehumidification abilities of an air-conditioning unit are
integrated to a capacity chart of a surface air cooler in air conditioning. This new chart shares several parameters such
as dry-bulb temperature (DB), humidity ratio, relative humidity (RH), specific enthalpy of air and capacity coordinates
as well as sensible and latent heat load (cooling and dehumidification capacity). The sensible and latent heat loads of
indoor air, the transient air-conditioning processes and the equilibrium state of indoor air given by a surface air cooler
in different indoor sensible and latent heat loads are illustrated on the capacity chart of a surface air cooler. Taking a
six rows JW20-4 type surface air cooler for example to introduce how to obtain the cooling and dehumidification chart
and how to use the chart. If the required indoor condition DB is 27±1 ºC and RH is 50±5 %, the appropriate operating
range can be found by using the cooling and dehumidification chart.