The effect of design parameters on the performance of water harvesting system

Abstract

A water harvesting unit is designed and built and test under Iraqi weather. The unit consists of a vapor compression unit. The compressor used in the unit of 372 W capacity. Many parameters are studied in this work, namely; the volume flow rate of air across the evaporator in the range from 224 to 540 m3/hr, the number of evaporator rows, and configuration of evaporator rows connection. As well as the effect of using evaporative cooling at the test room on the water production is studied. The result showed that the maximum water production for the two rows evaporator is 7.9 lit/day with a power consumption of 1.76 kW-h/lit. when the volume flow rate of air is 230 m3/hr, this amount of water production is increases to about 13.11 lit/day with a power consumption of 1.068 kW-hr/lit, when an evaporative cooler is turned on in the test room. Using 4 rows evaporator improved the water generation and power consumption by 26% and 10% respectively. As the evaporative cooler is used within the space the improvement of the two factors mentioned above are 49.5 and 19% respectively. Using six rows instead of two rows evaporator improve the water production and power consumption by 39 and 11% respectively as compared with the two rows evaporator. As the evaporative cooler is used the improvements are 56.5 and 17.8% respectively. The comparison between the four and six rows evaporator show insignificant increases in the water production and power consumption, which are 10 and 1.4 % respectively when no evaporative cooler is used, while with an evaporative cooler the improvement in the factors mentioned above are 4.6 and 1.6% respectively.