Desalination plant using a solar panel and closed air circuit

Abstract

The present invention is a structure that generates electrical energy and, at the same time and without water loss, desalinates the water above a solar panel in a transparent box by means of evaporation. The humid air is conveyed by means of fans through a closed circuit where the steam condenses and fresh liquid water is obtained. Subsequently, the air, which is now less humid, enters the transparent box again. 950 ml of fresh water is collected for 24 hours using a 48 cm by 35 cm solar panel. This amount is equivalent to approximately 6 litres of water per m2 per day. The maximum electrical power measured in the panel reaches almost 90% of the maximum power of the same panel outdoors and without water on top. For its industrial use, the invention can be built in a modular manner and can therefore be easily escalated.

Description

[0001] DESCRIPTION

[0002] SOLAR PANEL AND CLOSED AIR CIRCUIT DESALINATION PLANT

[0003] TECHNICAL SECTOR

[0004] The invention converts seawater into freshwater through the natural processes of evaporation and condensation, while simultaneously producing electrical energy. Therefore, the invention belongs to both the energy and water supply sectors.

[0005] BACKGROUND OF THE INVENTION

[0006] As is well known, solar panels convert sunlight into electrical energy. Electrical energy, regardless of how it was generated, is ubiquitous in our society and is used for a multitude of applications. In relation to this invention, one of those applications is desalination plants for generating fresh water. It's a process in which, without going into any detail, electrical energy is expended and fresh water is obtained from seawater.

[0007] There are other systems that extract fresh water, through condensation, from the air that blows freely over the earth's surface. These systems are installed, for example, in countries with hot, dry climates to provide water to the local population. These systems do not add water to the environment, but rather transform water from one form (vapor) into another (liquid). After passing through these systems, the outgoing air contains (even) less moisture.

[0008] However, the invention described here allows for the production of electrical energy and fresh water at the same time. The invention is based on the evaporation of seawater located above a solar panel and the subsequent condensation of the evaporated water using a closed air circuit. In this way, this invention produces electrical energy and adds fresh water to the environment, thus providing a good solution to the energy transition and the growing problem of fresh water scarcity in many parts of the world.

[0009] 1

[0010] SUBSTITUTE SHEET (RULE 26) EXPLANATION OF THE INVENTION

[0011] The main objectives of the invention are as follows: The aim is to achieve a system that allows for the generation of electrical energy and, at the same time, the production of fresh water using seawater as a source. Furthermore, it must be a zero-water-loss solution, meaning that all the saltwater used must be converted into fresh water. Finally, and especially for industrial applications, it must be a solution that can be easily scaled.

[0012] The operation of the invention is as follows:

[0013] The solar panel, exposed to sunlight, produces electrical energy and heats up. As it heats up, the salt water above the panel also increases in temperature, accelerating the evaporation process. In turn, the evaporation process moderates the temperature of the solar panel, thus increasing its efficiency. The airflow from three fans on the back wall of the transparent box draws the humid air down the sides of the solar panel. There, below the solar panel, three more fans (of the same type) push the humid air through cooling radiators, where the vapor condenses and falls as liquid fresh water down the drain, where it is collected. The air, now less humid, continues through the closed circuit and rises behind the transparent box toward the three fans on its back wall and re-enters the box. And so the process continues, generating electrical energy and liquid fresh water simultaneously.

[0014] Thanks to the closed circuit, all the water evaporated on the solar panel quickly becomes fresh water without any water loss.

[0015] It was found that the solar panel's maximum electrical power output reached 88% of the maximum power output of a panel of the same type and manufacturer outdoors and without water. The electrical power curves were measured using various resistors. Figure 4 shows the curves.

[0016] During a sunny and hot day in August, with the invention installed in Madrid facing south, a total of 1,000 tons of water was collected over a period of 24 hours.

[0017] 2

[0018] SUBSTITUTE SHEET (RULE 26) 950ml of water. This would be equivalent to 6 liters of water per m 2 per day. Referring to Figure 5, it is worth mentioning that without being exposed to the sun (between 10:00 p.m. and 9:00 a.m.), 210 ml of water were generated, equivalent to 22% of the total.

[0019] The advantages of this invention are:

[0020] • The generation of electrical energy and, at the same time, the production of fresh water using seawater as a source,

[0021] • There is no water loss, meaning all the salt water is converted into fresh water that is collected in the drain,

[0022] • The measured electrical power is almost at the same level as that of an outdoor solar panel without water,

[0023] • Existing materials and components that are widely available are used,

[0024] • For industrial applications, it can be built in a modular manner and can therefore easily grow,

[0025] • It allows deployment anywhere as it does not use any potentially dangerous technology.

[0026] PREFERRED EMBODIMENT OF THE INVENTION

[0027] With reference to Figure 1 (side view of the construction), Figure 2 (front view of the construction) and Figure 3 (solar panel with protruding edge) the details of the preferred embodiment of the invention are explained.

[0028] The invention uses widely available materials and components and was built in a laboratory setting and tested for several months to obtain reliable results.

[0029] A solar panel (2) of 20W- 12V Poly from the manufacturer Victron Energy has been used, with identification SPP20-12 / 3a, and with dimensions of 48cm x 35cm (0.168m 2 ). For this invention, this solar panel was adapted, building around it a transparent protruding edge (10) with a height of approximately 2 cm that allows storing salt water on top of it, as shown in figure 3. The supply of

[0030] 3

[0031] SUBSTITUTE SHEET (RULE 26) Salt water is introduced through a thin tube (8) through the right wall of the transparent box.

[0032] The solar panel sits horizontally inside a transparent box - or enclosure - (1) constructed of methacrylate walls and a sloping glass roof. The base of the four walls rests and is fixed to a light but strong 3cm high outer metal frame that has four legs one metre high from the ground. Sunlight falls on the solar panel through the side walls and through the roof. Electrical power is available through wires (7) coming out of the left wall of the transparent box. Electrical power was measured using 10Q, 32Q, 47Q, 100Q and 150Q resistors and a DT830B digital multimeter from the manufacturer Haoyue.

[0033] The transparent box has a width of 55 cm and a depth of 40 cm. Its front wall has a height of 6 cm and its back wall has a height of 44 cm. It has three fans (9) with a diameter of 12 cm of the Anima AF12 type from the manufacturer Tacens that blow the air towards the interior of the box. The bottom of the fans is two centimeters above the edge that surrounds the solar panel. The solar panel is placed centered against the bottom of the back wall leaving at the front and on both sides a space of approximately two centimeters between the walls and the panel. The box has no floor and to fix the solar panel, two parallel threads of thin steel were used that pass underneath it. Between them there is a distance of 25 cm and they are fixed to the side walls of the transparent box and to the external metallic structure. The solar panel is thus suspended in the air.The joints between the walls and the roof of the box are sealed to prevent air leaks.

[0034] In this invention, a closed circuit was created in which air constantly circulates through the transparent box, entering through its back and exiting through its bottom. To achieve this, a duct (6) was constructed using 200 gauge transparent polyethylene tubular plastic. It is a thin material and, being a tube, there are no air leaks. The duct starts at the bottom of the transparent box where the tubular plastic was sealed to the entire base of the box walls. The duct then continues half a meter downwards and where it curves backwards and goes up to reach the back of the transparent box and where the three fans located there were sealed.

[0035] 4

[0036] SUBSTITUTE SHEET (RULE 26) found. Using metal wires around the duct, it was strengthened, ensuring sufficient dimensions to conduct air properly. The tubular plastic was secured to this structure with adhesive tape.

[0037] Within this closed circuit, approximately 15cm below the solar panel, four radiators (4) were installed stacked one on top of the other, thus forming a block. The radiators used are XR7 360 type from the manufacturer Corsair and are cooled by a constant flow of water. On top of this block, three fans (3) were placed, one next to the other, thus covering the entire surface of the upper radiator, blowing the air downwards through the radiators. These fans are of the same type and size as those on the back wall of the transparent box. The tubular plastic duct was adjusted to the contour of the three fans ensuring that all the air passes through them. The vertical parts of the fan and radiator assembly were wrapped in cellophane to ensure that the air passes through the four radiators and does not escape through the sides.Approximately 20cm below the radiators, centered with respect to them, there is a small drain (5) for the evacuation of condensed water.

[0038] To measure air temperature and humidity at various points inside and outside the building, five DHT22 probes were installed. Figure 1 indicates the position of each of these five probes with the symbol To measure the water temperature, three DS18B20 type probes were installed: one inside the tube at the inlet (11) of the radiators and another inside the tube at the outlet (11) and a third inside the salt water above the solar panel. Figure 1 indicates the position of each of these three probes with the symbol

[0039] A program was developed for the Arduino UNO platform to collect measurement data from all probes in 30-second cycles. Using a Python program, the data is stored in Excel files on a computer.

[0040] Where cables or tubes had to pass through the plastic conduit or a transparent box wall, special care was taken to seal them to prevent air leaks.

[0041] 5

[0042] SUBSTITUTE SHEET (RULE 26) Finally, an insulating material was placed around the radiators and also around the metal part of the construction.

[0043] To cool the water flowing through the four radiators in this laboratory environment, a Hisense commercial freezer model FT258D4AWF was used, which was placed near the building. A Jonzzy 1800L / H 25W submersible water pump was used to pump the water through its closed circuit.

[0044] BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 shows a side view and Figure 2 shows a front view of the invention. These two figures are drawn to scale. To simplify the graphic presentation, the figures do not show the metal structure supporting the invention. The arrows indicate the direction of air flow in the closed circuit. In the side view, each type of probe is indicated by its corresponding symbol: each DHT22 probe with the symbol ® and each DS18B20 probe with the symbol .

[0046] Figure 3 shows the solar panel with its raised edge that allows salt water to pass over it.

[0047] The numbering of the construction elements in these three figures is:

[0048] 1. Transparent box,

[0049] 2. Solar panel,

[0050] 3. Three fans above the coolers,

[0051] 4. Four radiators to cool (coolers) the humid air,

[0052] 5. Drain,

[0053] 6. Closed air circuit,

[0054] 7. Electrical cables of the solar panel,

[0055] 8. Saltwater inlet pipe,

[0056] 9. Three fans on the back wall of the transparent box,

[0057] 10. Fill the top of the solar panel with (salt) water,

[0058] 11. Water inlet and outlet pipes from the coolers.

[0059] Figure 4 shows the measured electrical power (averaging the power

[0060] 6

[0061] SUBSTITUTE SHEET (RULE 26) measured at 2:45 p.m. and 3:45 p.m.) of the plate with salt water on it inside the transparent enclosure compared to a plate of the same type and manufacturer outdoors without water on it.

[0062] Figure 5 shows the amount of fresh water produced over 24 hours.

[0063] INDUSTRIAL APPLICATION

[0064] Without water, there is no life. And without electricity, (human) life is not easy. Therefore, they are two key elements for life. This is what forms the basis for the development of the invention and its presentation in this patent process. Implemented on a large scale, a system based on this invention in sunny locations with access to seawater will allow for the reliable generation of significant electricity and large quantities of fresh water. The positive impact on people's lives and, extrapolated, on a country's economy can be very significant; clean water increases hygiene, preventing disease, and crops would no longer be lost due to periods of drought. Water is also key for fauna and flora, thus contributing to the development of more green spaces where they currently do not exist or have disappeared (e.g., in the Sahel region), thus promoting the richness and diversity of nature.

[0065] The invention is intended to be implemented on a large scale because more and more electrical energy will be needed, and the constant and reliable production of large quantities of fresh water is becoming increasingly necessary.

[0066] The industrial application or implementation of a large-scale system of this invention is based on increasing the surface area of ​​the solar panels (2), thus converting them into a large power plant and a large water production plant. The fresh water produced can be used for animals, agriculture, and flora. After purification, the water will be suitable for human consumption.

[0067] The closed air circuit would be implemented using custom-made ducts (6) made of durable material. It would be possible to consider developing modules of 5, 10 or more solar panels together in a transparent box (1) with their (larger) fans. These modules are relatively easy to transport and implement. To cool the large volume of circulating humid air, heat exchangers (4) can be implemented.

[0068] 7

[0069] SUBSTITUTE SHEET (RULE 26) where the heat portion is immersed in seawater and the cold portion cools the humid air for massive condensation of moisture. Immersing the heat portion in saltwater improves the efficiency of the heat exchanger and simultaneously heats the saltwater before it reaches the solar panels, accelerating the evaporation process and thus increasing the system's freshwater production.

[0070] 8

[0071] SUBSTITUTE SHEET (RULE 26)

Claims

CLAIMS 1. A construction that, by taking advantage of sunlight, generates electrical energy and at the same time produces fresh water through the evaporation process of salt water present on top of one or more solar panels and subsequent condensation. The construction is characterized by comprising one or more solar panels (2) with salt water on top, a transparent box (1) that encloses said plate or plates from above and on its four sides, an inlet (8) for salt water, an electrical connection (7), a closed air circuit formed by a duct (6) through which the air can exit the box (1) on one side and re-enter it on the other without losing water, and a drain (5).

2. A construction according to claim 1, characterized in that there is a volume of salt water above the solar panel (2). This is achieved by means of a protruding edge (10) glued around the solar panel.

3. A construction according to claim 1, characterized by comprising a duct (6) which in turn comprises fans (3) and (9) to circulate the air and radiators (4) to cool it, and a drain (5) to evacuate the condensed water. 9 SUBSTITUTE SHEET (RULE 26)

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