ES2323340B1 - SOLAR ENERGY WATER DESALATION SYSTEM. - Google Patents

Abstract

Water desalination system by energy solar.

The system is specifically designed to desalinate brackish water from the sea, using as energy to the implementation of it, solar energy. The system is based on a process of humidification and dehumidification of the air to atmospheric pressure, carried out in a separation tower thermally insulated, which is divided into two spaces linked by the two ends of said tower (3), with a camera of evaporation (4) and a condensation chamber (5). A set of solar collectors heat the water to the proper temperature that it is introduced in the separation tower (3), specifically in the evaporation chamber (4) through a sprinkler (9), where a air flow generated by fans (8) favors the evaporation of water, steam that will condense in the chamber (5), specifically in the condenser (10), being stored in a tank lower (13) from which it is extracted for consumption.

Description

Water desalination system by energy solar.

Object of the invention

The present invention relates to a system of desalination of seawater, for its transformation into water drinking water, which uses the sun as an energy source, with the consistent and positive impact at cost level.

The object of the invention is to achieve a system capable of materializing in an installation with low costs of maintenance and good efficiency, whose production costs be competitive with those of other desalination systems.

Thus, the invention aims at get drinking water for public use from seawater, through an energy-based desalination process solar.

The invention is therefore applicable in the industry scope for water purification Marine.

Background of the invention

As is known, the system most commonly used in the field of seawater purification is that of reverse osmosis, system that brings with it some requirements energy sources, basically at the expense of oil and its derivatives, and with a considerable environmental impact.

Another commonly used system is that of thermal distillation, whose problem is mainly focused in that the great specific heat of water, and in particular its great heat of vaporization, imply that a large amount is necessary of energy to evaporate large volumes of water with the consequent and negative impact on the economic aspect, similar to systems based on reverse osmosis.

Desalination technologies through solar energy are the most promising in the today, given the abundance of places where there is a shortage of drinking water, are in close proximity to the sea and receive Good levels of solar radiation.

However, these technologies are slowed down advance by not having managed to reach the cost levels similar or inferior to those of other desalination methods of large volumes of water, such as reverse osmosis or conventional thermal distillation.

Description of the invention

The system that the invention proposes comes to fill this technological gap, achieving the desalination of water by distillation, with low maintenance costs, and with also low production costs, mainly due to the use of renewable energies, and more specifically when use of solar radiation.

To do this and more specifically the principle operating system of the invention, is based on the change phase by means of humidification and dehumidification systems air, which achieve better efficiency than other systems by avoiding having to bring the water to a boil to get steam. The radiant heat of the sun is used to heat the water, and it enter this with sprinkling in an enclosure where it comes into contact with the air, moistening it, so that in another part of the enclosure the air comes into contact with cold surfaces and detaches from it humidity.

According to another feature of the invention the installation will be located on a platform floating inland, which allows portability and facilitates have the necessary surface to place it.

The platform can be towed along the coastline to specific points where it is required its use, to once there proceed to anchor and perform the supply.

The aforementioned air humidification system, at save the heat of evaporation, it does not require a large amount of energy to evaporate large volumes of water, since it plays with the amount of steam that can keep the air in suspension to evaporate almost all the water without need to raise its temperature to the point of boiling.

A critical factor for the right one operation of the system of the invention, is the speed of evaporation of hot water, which depends on the amount of surface exposed to the passage of air so that it can be dragged humidity. The proposed solution in this regard is the sprinkling of the water by physical means, getting a better surface Specific air-water contact.

Description of the drawings

To complement the description that is being performing and in order to help a better understanding of the characteristics of the invention, according to a preferred example of practical realization of it, is accompanied as an integral part of said description, a set of drawings where with character Illustrative and not limiting, the following has been represented:

Figure 1.- Shows, according to a representation schematic side elevation, a water desalination plant by solar energy, carried out in accordance with the system that constitutes the object of the present invention.

Figure 2.- Shows a representation upper floor schematic of the set represented in the Figure 1.

Figure 3.- Shows an elevation view side and in diametral section of the separation tower that participates in the installation of the previous figures.

Figure 4.- Shows, finally, the scheme thermodynamic system operation, indicating the flows of water and steam, and heat exchange points.

Preferred Embodiment of the Invention

In view of the figures outlined you can be observed as the solar energy water desalination system that the invention proposes, is materialized in a marine plant that it consists of a floating platform (1), on which two settle basic and auxiliary structures to carry out the desalination. Most of the surface of this platform It is covered with solar panels (2), used to capture energy heat from the sun and transmitted to the water. These panels consist of an automated tilt system to be arranged in each moment at the best angle to the sun, while the platform (1) will incorporate a system that allows small rotational or rotational displacements on itself, or on the sea surface, to be able to conveniently guide the group of panels towards the sun, at every moment of the day, with what achieves a practically labeling effect on the mobility of said panels, to be able to move on an imaginary axis horizontally and simultaneously on an also imaginary axis vertical.

Within the aforementioned basic structures, the main structure of the plant is a separation tower (3), the one represented in detail in section in figure 3, where carries out the water distillation process. This tower of separation materializes in a tank with walls thermo-insulators, which is divided into two chambers separate, an evaporation chamber (4), lower, and a chamber of condensation (5), superior. These two cameras (4) and (5) of the tower (3) they are communicated in two points, specifically in an area (6) near its base and an area (7) near its upper extremity. These chambers (4) and (5) are at atmospheric pressure, but closed to air.

The purpose of this structuring for the separation tower (3), is that convection currents are generated in the air inside the tower, take it to make a circular path between both chambers, heating and saturating of moisture in one of them and leaving this condensed moisture in the other.

These currents can be controlled artificially by fans (8).

Water is introduced into the tower in the form turbulent through a sprinkler system (9), which dispenses in small drops, to improve its evaporation rate. These drops come into contact with rising currents due to  convection of air that drags them up the evaporation. The moist air enters the upper opening of the condensing chamber now running downwards and cooling on contact with the fins (10) present therein, at the same time that it is releasing excess moisture leaving drops condensed on the surface of said fins. The interior of the condensation chamber is labyrinthine and furrowed by those mentioned thermal exchange fins (10), through which the cold water supply. Water carries out a thermal exchange here which begins to raise the temperature already before being sent to panels to continue to heat up, serving at the same time to cool and condense water vapor inside the tower, which improves efficiency

At the bottom of the evaporation chamber (4) it establishes a reservoir (11) on which water does not accumulate evaporated, with excess salt. This water will be discarded directly to the sea through a valve, or it will also be used to preheat part of the supply water using an exchanger (12). At the bottom of the condensation chamber (5) there will also be another reservoir (13) in this case for drinking water, which will be temporarily held before being sent to the ground for consumption.

Another of the fundamental elements of the installation is a thermo-insulated tank (14), which serves as an energy storage system, allowing to reserve the thermal fluid that runs through the panels and has reached the operating temperature in the hours of maximum sunshine, for hours with less sunlight. This improves the joint installation performance, by allowing activity night of it. It also includes an exchange system for heating the supply water.

It only remains to point out finally that the platform floating (1) will be supported by floats (15) of polyethylene or polypropylene.

The operation of the plant includes the step of the supply water through the condensation arm of the tower, through its interior through the fins of the condenser (10) and putting it in superficial contact with hot and humid air inside, thus making a first heat exchange. He heat exchange with the waste brine can be performed in parallel or before the passage of this water through the condenser. In solar collectors (2) a thermal oil will raise its temperature above 100 ° C and will be stored in the tank (14), to directly heat the supply water or be stored until another time, to perform the heating also in the hours of less sun and during the night. The oil is automatically pumps (16) from the tank to the panels, depending on the solar radiation at all times. Water of supply heated in the thermal tank passes through a pump (17) that sends it to the vaporization tower (3), at a temperature between 70 and 90ºC, so you don't need to get the boiling water.

The supply system comprises one or several pumps and filter media, and includes a system of chemical pre-treatment to prevent proliferation of algae and fungi in the installation. The pumps (18) are located below sea level and have filters at their entrance to prevent the entry of solids in the pipes. This water is carried to the top of the turret and then let down by pipes inside the condensation chamber, in enveloping shape with internal steam ducts for refrigerate these. After completing this tour, some of the water will be discarded and returned to the sea, and another part will become water supply and will pass heat exchanger to raise your temperature to reach the optimum for the operation of the separation tower Before that, it will go through a new filter and It will do the necessary chemical pre-treatment.

The heat energy collection system solar is formed by a network of pipes that passes oil thermal by several solar panels heat collectors, for example CPC type, until it rises to temperatures above 100ºC. A heat exchanger attached to the thermal tank is used to transmit the heat energy of the oil to the supply water, being equipped with monitoring and control systems for Control the final temperature of it. The platform will feature additional mechanical systems that will enable the best orientation of it to collect the most radiation solar.

Claims (6)

1. Solar water desalination system, based on a water distillation process, characterized in that said distillation process is carried out in a separation tower (3) in which two chambers, laterally adjacent, are defined of evaporation (4) and another of condensation (5), both chambers being related to each other through its lower extremity (6) and its upper extremity (7), in order to generate air convection currents within the tower, with cyclic path through both chambers (4) and (5), heating and saturating with moisture in the chamber (4) and leaving said condensed moisture in the other chamber (5). 2. Water desalination system by solar energy, according to claim 1, characterized in that in the evaporation chamber (4) a sprinkler device (9) for supplying brackish water is established, which is dispersed in fine drops, settling in the bottom of this chamber (4) a reservoir (11) for accumulation of non-evaporated water and with excess salt, which is forwarded to the sea, while in the condensation chamber (5) a condenser (10) with fins is established determinants of a labyrinthine passage for air, and at the bottom of said chamber a reservoir (13) for collecting condensed and desalinated water. 3. Solar water desalination system, according to any of the preceding claims, characterized in that at any point of the cyclic route for the air through the chambers (4) and (5), one or more fans (8) are established for forced air circulation inside the tower (3). 4. Solar water desalination system according to claim 2, characterized in that the condenser (10) constitutes a means for preheating brackish water, which circulates inside said condenser before reaching the spray device (9 ). 5. Solar water desalination system, according to any of the preceding claims, characterized in that said floating platform (1) is mostly covered with solar panels (2), which leave free space for location of the separation tower (3 ), together with the establishment of a bulky tank (14), with thermo-insulated walls as well as the separation tower (3), which constitutes an energy store that accumulates the thermal fluid that runs through the solar panels (2) and Once the operating temperature has been reached during the hours of maximum sunshine, this heat is supplied to the separation tower (3) when necessary, such as during night hours. 6. Solar water desalination system according to any of the preceding claims, characterized in that the floating platform (1) is supported by floats (15) of polyethylene, polypropylene or any other appropriate material to allow portability by sea drag up to the place of operation, where the platform is able to rotate on itself, in order to properly orient the solar panels (2), which are in turn unitarily oriented on an imaginary horizontal axis, having been provided that both the orientation of the platform as a whole, as the unit orientation of the solar panels is carried out through an automatic solar radiation tracking system.