A. Tamimi

Solar desalination with a humidification-dehumidification cycle: performance of the unit

Abstract The closed air cycle humidification-dehumidification process was used for water desalination using solar energy. The circulated air by natural or forced convection was heated and humidified by the hot water obtained either from a flat plate solar collector or from an electrical heater. The latent heat of condensation was recovered in the condenser to preheat the saline feed water. Two units of different sizes were constructed from different materials. The productivity of these units was found to be much higher than those of the single-basin stills. Moreover, these units were capable of producing a large quantity of saline warm water for domestic uses other than drinking. No significant improvement in the performance of the desalination units was achieved using forced air circulation at high temperatures. While at lower temperatures, a larger effect was noticed. This can be related to the low heat and mass transfer coefficients at low temperatures and to the non-linear increase in the water vapor pressure with temperature.

Performance of a solar still with reflectors and black dye

Abstract A solar still was constructed and operated with and without reflectors and black dye under different weather conditions. It is found that addition of a black dye to the water basin and the installation of reflectors (mirrors) on the inside walls of the still enhance productivity considerably

Extraction of jojoba oil by pressing and leaching

Abstract Jojoba oil extraction by pressing alone, pressing followed by leaching, and leaching alone were investigated. The extraction process by first and second pressing followed by leaching gave about 50% by weight oil with reference to total seed, which is in agreement with what has been reported previously. The extraction by leaching process was carried out using different solvents. These solvents were; hexane, benzene, toluene, petroleum ether, chloroform, and isopropanol. Hexane, benzene, and petroleum ether gave the highest yield (all about 50% by weight oil with reference to total seed), but when cost is considered, petroleum ether is recommended as the best solvent to leach jojoba oil. The yield obtained in this work for leaching by hexane and benzene are 3–5% and about 10% for isopropanol more than those reported in the literature. Traces of solvent remained with the extracted oil after simple distillation followed by a second stage distillation via a Rotavapour apparatus. These traces slightly affected some of the oil properties such as pour point and flash point.

A simulation study to improve the performance of a solar humidification-dehumidification desalination unit constructed in Jordan

Solar desalination with a humidification-dehumidification process has proven to be an efficient method of utilizing solar energy for obtaining fresh water from saline water. The reason behind the success of this method is the use of latent heat of condensed water vapor. With proper use, this process efficiency could be high. A simulation program was written to describe the performance of such units. It was found to predict the performance of a desalination unit constructed in Jordan in 1993. The simulation program was then used to optimize the unit performance by studying the effect of different parameters such as the condenser and humidifier area, as well as the effect of some of the operating conditions such as the feed water flow rate to the unit.

Parametric Investigation of Oil-Shale Extraction with Organic Solvents

Abstract Oil-shale deposits at El-lajjun, a rich oil-shale area south of Jordan, were extracted with organic solvents. The amount of extracted oil depends on the operating conditions and parameters which affect the process. The effects of particle size, extraction time, extraction temperature, mixing rate, solvent-to-oil-shale ratio, and type of solvent were investigated.

Energy situation in Jordan

Abstract Jordan is a non-oil producing country. The imported oil bill is equivalent to about 10% of GNP and 50% of national export. In this work energy consumption by various sectors is presented and discussed. Also, all other energy alternatives are examined.

Analysis of energy consumption in Jordan

Abstract Energy consumption in Jordan was analysed and correlated over the last seven years for the period 1985–1992. The results were presented fairly by second or third degree polynominals with less than ±5% error.

Drying characteristics of oil shale

The tray-drying process for oil shale has been analyzed and modeled. The results for the falling drying-rate domain were correlated with a generalized exponential model that incorporates the effects of dry-bulb temperature and particle size. The results indicate that the drying process is a strong function of the operating dry-bulb temperature. The effect of temperature is more pronounced for particles smaller than 2 mm than for larger particles. The particle size was found not to be important at low temperatures of about 50 °C but was important for particles larger than 4 mm at temperatures greater than 67 °C.

Analysis of electrical energy generation and consumption in Jordan

Abstract Electrical energy generation and consumption in Jordan are analysed and discussed. The consumption levels in various sectors were correlated and expressed by polynomials of second or third degree with an error of ±5%.

Analysis and performance of an extended-surface, tubeless, flat-plate solar collector

A novel, extended-surface, flat-plate solar collector has been investigated and tested. Comparative test results with an identical tubeless, flat-plate solar collector (without surface extension) indicate that the surface extension by indentation improves the collector efficiency almost in the same proportion as the absorber area is increased by extension for the same heat flux.