**1.1. Experimental heat exchanger**

The experimental heat exchanger is of tubular type, cross flow occurs at 90°, it comprises vertical tubes placed in a 10 × 4 matrix in an arrangement of square type [4] as shown in **Figure 1**.

**Figure 1.** Frontal, lateral, and isometric view from heat exchanger (dimension in millimeters).

The heat exchanger is provided with an acrylic duct that is used to conduct the air to the tube arrangement (**Figure 2**). Water flows through 40 tubes vertically and constantly by means of a recirculation circuit which comprises a pump and a reservoir, and the air is supplied by a vertical fan.

**Figure 2.** Isometric view of air duct and heat exchanger.
