Guillermo Hernandez-Cruz

Total Energy Balance Method for Venting Electric Clothes Dryers

A total energy balance method for venting electric tumbler dryers was developed and the experimental methodology and calculation details are provided in this article. The energy to evaporate the water in the load; the energy to heat the water, textile, and dryer; energy losses by convection and radiation; and the energy not used in the process were considered to calculate the total output energy. This method was applied to a domestic venting electric tumble dryer. The results of the method suggested areas of improvement. The maximum difference between the measured total input and the calculated total output energies was 2.6%, indicating the accuracy of the method.

DYNAMICS OF BOILING FROM A SHORT CAPILLARY TUBE

The phenomenon of boiling from a short capillary tube is studied experimentally, with the objective of better understanding the dynamics of phase change at nucleation sites. Boiling is achieved by electrical heating of a resistor in a short, water-filled capillary tube immersed in a pool of hot water. Bubble departure is detected by a phototransistor when a bubble passes through a laser beam. Two qualitatively different behaviors are observed. At low heat rates, bubbles depart with two possible periods. There are packages of a small number of bubbles departing with an almost constant period, separated by sets of two bubbles emitted at a shorter period. The behavior at large heat rates is singly periodic. In both cases, a small, apparently stochastic perturbation is superposed on the regular pattern, A statistical analysis of the experimental data is also carried out. For the low heating case, the output signal of the detector has been used as a time series to reconstruct the system attractor in phase spac...