A Porous Ceramic Evaporator Wall for a Single Room in Arid Housing: Computed Indoor Temperature Reduction, Water Use per Degree, and the Humidity Ceiling

SIMULATED, NOT MEASURED. A direct evaporative cooling assembly for arid-climate housing is specified: a porous ceramic/clay evaporator wall of 8.0 m2 net area, gravity-fed, delivering 600 m3/h of air at an evaporative effectiveness of 0.85 into a room of 4.0 x 3.5 x 2.7 m with 28 W/K envelope conductance and 400 W fixed gains. At 40 C and 20 percent relative humidity outside, the simulated indoor temperature is 29.00 C, a reduction of 11.00 C, for 47.21 litres of evaporated water per 12-hour day, i.e. 4.29 litres per day per degree. Across eighteen cases (35, 40 and 45 C; 10-60 percent relative humidity) the water price per degree lies between 4.05 and 5.95 litres per day per degree, and the largest reduction is 15.63 C at 45 C and 10 percent humidity. The humidity ceiling, defined as the humidity at which the reduction first falls below 3.0 C, is 62.7 percent at 40 C (60.3 percent at 35 C, 64.6 percent at 45 C). All numbers are outputs of the deposited computation script; no hardware was built or tested.