One of the main functions of refrigeration systems is to decrease temperature of air flow. One thing that always occurs naturally along with decrease in temperature is the moisture reduction. In the air conditioning, for comfort or industrial, decrease of moisture is usually considered as desirable goal. In this case is emphasized on cooling and reduction of air humidity at temperatures range 5 to 35 oC.
Most of cooling coil is usually consists of pipe with fins attached to the outside, it is intended to expand surface area in contact with air. Generally, its convection coefficient is lower than water. Water flows inside pipe and air flows outside finned pipes.
Some terms and notions of cooling coil construction that as often used as follow:
- Face area of the cooling coil: the cross-sectional area of air flow at the entrance of cooling coil.
- Face velocity of the water: the volume of air flow rate is divided by surface area coil.
- Surface area of the coil): the heat transfer surface area in contact with air.
- Number of rows of tubes: i.e. number of rows (tubes, pipes) that are in the direction of air flow.