Pioneer Solar Water Desalination System: Experimental Testing and Numerical Simulation

A pioneer system of solar water desalination was constructed, tested and numerically simulated for moderate latitudes, Cairo 30 °N. The humidification/dehumidification (HD) process is considered in this system. The salt water is heated by either solar energy or/and auxiliary heater before injection inside an insulated desalination chamber using an air atomizer. The air is supplied into a condenser by a 0.4 kW blower and later on it pulls hot salt water up through the atomizer from an insulated tank. By this idea the air is preheated inside the condenser and is used as a water pump. The flashing water is evaporated and condensed simultaneously above the condenser surface. A 2.39 M2 flat-plate solar collector is used to heat the salt water existed in an insulated tank. The tank opening is closed by the chamber one. By this way the salt water is circulated naturally inside the solar water heater where it is forced inside the desalination chamber. A numerical simulation of the considered system was developed and validated. It was provided a mathematical model of each system component. The system was successfully tested using either solar or/and auxiliary energies. It can produce about 36 liter daily of purified water where the using of solar energy alone can obtain about 12 liter on clear days. To visualize the heat and mass transfer inside the chamber temperature and humidity distribution were measured. The annual and monthly performance of the system is presented. In addition an empirical equation of the distilled water quantity is obtained versus the incident solar radiation. Moreover, economic study was provided and it is found that one liter of distilled water can cost about 0.2 US$ using the considered system. Key words: Solar desalination; Air atomizer; Air condenser; Thermosiphon; Humidification/dehumidification; Numerical simulatio

Performance of a Solar Chimney Under Egyptian Weather Conditions: Numerical Simulation and Experimental Validation

High solar radiation and ambient temperature, and large desert in Egypt are excellent conditions to install efficiently solar chimney power plants there. Therefore this research aimed to develop a validated mathematical model and governing equations of solar chimney. It is proposed to improve the performance of solar chimney under effects of various parameters, and study of possibility of installing solar chimney in Egypt. The mathematical simulation of the solar chimney has been developed including all its performance parameters, dimensions (of collector, chimney and turbine) and the metrological data; which were considered as inputs of the simulation program. A comparison between the mathematical and experimental performance has been investigated to validate the mathematical simulation. The mathematical model has been used to predict the performance of the solar chimney power plant over a year in Egypt. It is used to study of effects of geometrical parameters, and investigate possibility of the optimum geometrical dimensions. It is obtained that there is in fact no optimum physical size for such plants without considering the economical constraints. The chimney height has a significant effect in the chimney performance. Visualizing of annual performance of the solar chimney would seem to be essentially a power generator in Egypt if it installed in a large scale.Key words: Solar chimney; Numerical simulation; Annual performance; Experimental validation; Optimizatio

Innovative solar natural vacuum desalination system

The main target of the work is a design of an innovative solar natural vacuum desalination (SNVD) system and improve performance of such systems. The natural vacuum is developed by raising up an evaporation chamber to 9.8 m above the ground. The waste heat is efficiently utilized in that system to minimize the system heat loss. The fresh water is first preheated by condensing vapor from the evaporation chamber before it is heated by a flat-plate collector as a heat source of the evaporation chamber. On the other side, the sea water is preheated by the produced warm water, and it is reheated by the exit brine water before it is supplied into the evaporation chamber. A mathematical model and a transient simulation were established to investigate the annual performance of system. A heat balance of each system component was provided to estimate the inlet and outlet temperature and flow rate of it. Moreover, the collector area was estimated based on assumed mass flow rates of both feed sea water and coolant water. It was found that the system can produce a daily production of 6.2 L of pure water per a quadratic meter of collector on annual average basis. That Productivity can be estimated as 1.12 L of water per kWh solar radiation. Accordingly, the evaporation rate was estimated as 2.82% while the gain output ratio (GOR) was obtained as 0.63. The system performance can be accepted compared with the corresponding published systems

How to select a collector?

The collector is the main element that affects the solar system's performance. The collector's efficiency is affected by its operating temperature. Different levels of heating were considered for a milk-processing factory. The optimal collector type (i.e. the one with the minimum payback period) that can be used for these levels was deduced.Food industry Milk processing Optimum Payback Solar collector