Portable and autonomous desalination system

The portable and autonomous desalination system is an autonomous reverse osmosis (RO) desalination system utilizing power from a combination of electricity generation and storage sources that include a photovoltaic (PV) unit, a vertical-axis wind turbine (VAWT) unit, and an electricity storage unit. Electric power from PV, VAWT or storage units or a combination of these units is provided, depending upon the availability of sunlight or wind, or for night operation for water desalination using the reverse-osmosis process. The unit is portable, environmentally friendly, self-sufficient and self-sustaining in terms of supplying the electricity and fresh drinking water needs of the typical household. Multiple PV-VAWT-RO desalination units are combined together to provide fresh, clean water and electricity for communities of various sizes. A small-size, straight-bladed vertical axis wind turbine runs at very low wind speeds for urban operation.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to desalination units, and more specifically to using photovoltaic cells and wind electric power generators to power a reverse osmosis desalination unit.

2. Description of the Related Art

Although the use of wind energy for electricity, solar energy for distillation or desalination, or a combination thereof has been attempted in the related art, the use of the present combination of wind using a vertical-axis wind turbine, solar energy using photovoltaic cells and a desalination unit based on reverse osmosis process to provide portability, and increased efficiency and effectiveness is believed to be non existent in the literature.

Thus, a portable and autonomous desalination system solving the aforementioned problems is desired.

SUMMARY OF THE INVENTION

The portable and autonomous desalination system is an autonomous reverse-osmosis (RO) based desalination system utilizing power from a combination of electricity generation and storage sources that include a photovoltaic (PV) unit, a vertical axis wind turbine (VAWT) unit, and an electricity storage unit.

Electric power from PV, VAWT, storage units, or a combination of these units is provided, depending upon the availability of sunlight and wind, for night operation for water desalination using the reverse-osmosis process. The unit is portable, environmentally friendly, self-sufficient and self-sustaining, while supplying the electricity and fresh drinking water needs of the typical household.

Multiple PV-VAWT-RO desalination units may be combined together to provide fresh, clean water and electricity for communities of various sizes. A small-sized straight-bladed vertical axis wind turbine runs at very low wind speeds for urban operation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown inFIGS. 1-3, the present invention relates to an environmentally friendly, self-sufficient and self-sustaining desalination system10that can provide the electricity, fresh drinking water, irrigation, and/or recreational needs of a small community located near a salt water source, e.g., a sea or an ocean. Multiple PV-VAWT-RO desalination units can be combined together to provide fresh, clean water and electricity for communities of various sizes.

As shown inFIG. 1, the system10can include a vertical axis wind turbine (VAWT)100having blades25suspended by frame members20that extend from rotating pole15, multiple arrays of solar panels30, a reverse-osmosis based desalination unit39, a permanent magnet-based electricity generator11, and an electrical storage system comprising batteries, all supported by a portable mounting base40. Wheels are disposed on the bottom of the base40to facilitate portability of the base40. A vertically disposed telescopic hub12can raise or lower the wind turbine100. As shown inFIG. 2, horizontally disposed telescopic arms200may be utilized to extend or retract blades25. As shown inFIG. 3, the vertical axis wind turbine may incorporate curved blades300.

The Reverse Osmosis (RO) unit39is disposed in a wheeled base40. Gravity feed inlet45permits salt water to enter tubes55. Desalinated water is removed via water outlet50, also connected to tubes55. The tubes55are disposed in a stacked manner on portable base40. The tubes55are stabilized on base40by a front planar vertical wall41aand a rear planar vertical wall41b. The vertical walls41aand41bhave bores through which the tubes55are supported. Detailed operation of the RO unit39is known by persons having ordinary skill in the art.

The straight-bladed vertical axis wind turbine (VAWT)100is designed to operate at low wind speeds, i.e., cut-in speeds of about 2-3 m/s, enabling the turbine to be utilized for providing fresh water and electricity within the urban environment where wind speeds near the surface can be as low as 2-3 m/s during a significant part of the year. The advantage of using a VAWT, such as VAWT100, is inherent in the small-scale straight-bladed VAWTs that are now being used in a host of applications within the urban environment, such as traffic signals, road-side advertisements, parking meters, street and park lighting systems, to name a few.

Moreover, other advantages inherent in a straight-bladed VAWT, as compared to the conventional horizontal-axis wind turbine or HAWT, include omni-directional operation capability (a VAWT can operate with wind from any direction, whereas a HAWT needs to be oriented into the wind for maximum output, which may require power and the use of a wind monitoring system) and low cut-in speed capability (similarly rated HAWTs require significant wind speeds (>5 m/s) for start-up to overcome inertia and gravity) and any useful power output). Greater than 5 meter/second wind speeds are typically not available near the ground in an urban environment, and thus HAWTs must be installed on top of high towers so that the HAWT and its blades are above any ground obstructions to the local wind. The need for high towers for HAWTs makes them very unsuitable for the urban environment, as well as very difficult to move.

The small size of VAWT100also makes it very portable as compared to a HAWT of similar size. Straight-bladed VAWT100is simpler in design, and therefore easier and cheaper to manufacture as compared to a HAWT.

The VAWT system10is also simple to maintain because of its straightforward design. Moreover, the electricity generator11is preferably located at the base40for ease of maintenance, whereas in the case of a HAWT, the generator is usually mounted on top of the tower along with the HAWT unit. This fact alone makes the maintenance of a VAWT very easy and inexpensive when compared to the maintenance of a HAWT.

Thus, the above inherent advantages of small-sized straight-bladed VAWTs, such as VAWT100, in desalination system10are readily apparent when it comes to efficiency, low-cost, low-maintenance, portability, environmental soundness, self-sufficiency, self-sustainability and autonomy.

The power generated by VAWT100in system10can be used to run small reverse-osmosis desalination unit39to provide fresh water to a household. Use of photovoltaic (PV) arrays30and electrical storage units can supplement the power in the absence of wind or daylight.

The PV-VAWT-RO system10can take advantage of the prevailing winds (utilizing trade winds or land and sea breezes near coastal areas) when it is placed downstream of convergent channels or ducts aligned with the direction of the prevailing winds to further enhance the power output from VAWT100.

The convergent channel or passage formed by a concrete structure or by a specific arrangement of trees may be utilized to provide an extra boost to the wind speed available to system10. Knowledge of prevalent wind directions, particularly the trade winds {trade winds blow in different directions in the northern (from northeast) and southern (from south east) hemispheres} and the land/sea breezes near coastal areas can be used to orient the convergent channels parallel to the wind to maximize outputs from the PV-VAWT desalination units10.

As shown inFIG. 4A, blades400aare crescent-shaped, or more particularly, have a concave blade face at the ends of elongated rotor arms extending radially from a hub that provides aerodynamic drag in the face of wind normal to the blades400ain order to facilitate operation of the VAWT as a drag device. Conversely, as shown inFIG. 4B, blades400bare teardrop-shaped airfoils disposed normal to the elongated rotor arms in order to facilitate operation of the VAWT as a lift device due to differences in air pressure from the flow of wind over the opposite faces of the blades400b.