AU2021105568A4 - An apparatus for water distillation and method thereof - Google Patents

Abstract

The present invention discloses an apparatus and method of producing distilled water from the normal water using solar irradiance. Present invention intended to develop an apparatus to produce water distillation at high yield rate for domestic as well as commercial applications by a compact apparatus arrangement. Said water distillation apparatus comprising a D-pate evacuated collector unit (100) which is integrated with a non-submerged blackened surface solar still unit (200) and a condenser unit (300); the said condenser unit and non-submerged blackened surface solar still unit (200) further coupled with a steam ventilation unit (400) to produce steam ventilation and negative pressure inside the apparatus. Thin layers of hard water are being formed by a plurality of D-plates (43)and an inner surface (10) for the fast evaporation of thin water layers. Said apparatus also flexible to operate in two different active and passive modes, just by changing few system settings. 1/7 24 2 22 32-3 23 30 - 25 335 333 7 25 227 377 16 15 Fig 1A

Description

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AN APPARATUS FOR WATER DISTILLATION AND METHOD THEREOF FIELD OF THE INVENTION

[0001] The present invention relates to a solar distillation system. In particular, the present invention relates to an apparatus for producing distilled water and method thereof.

BACKGROUND AND PRIOR ART

[0002] The simplest way of achieving water distillation is to evaporate water and then condense it on a condensation surface or inside a condenser. Use of solar radiation for producing water distillation is an accretive and economic method to produce pure water. Variety of distillation processes such as multi-stage fresh evaporation, reverse osmosis, electro dialysis and multi-effect evaporation are not cost effective for large fresh water demands. Thus, distillation by solar energy is a striking way because of its non-complex and economical technology. Also, such systems require low maintenance and less skilled technicians for the operation of systems.

[0003] A number of different types of system and methods for producing distilled water from saline/hard/impure water are available in the prior art. For example, the following patents and research articles are provided for their supportive teachings and all incorporated by reference:

[0004] Sodha et al., 1981b discloses- in a multi-wick solar still, the maximum temperature difference between the condensing cover and water surface can be achieved by reducing the heat capacity of the water mass in the basin. In other word, a water film is maintained on the absorber for fast heating and quick evaporation. The water film is achieved by using a porous multi-wick (jute cloth). Each jute cloth layer is separated from other by providing a black polythene sheet between them so that each jute cloth can act independently. [See: SOLAR ENERGY (Fundamentals, design, Modeling and applications) by G.N. Tiwari, revised edition 2013].

[0005] Kumar and Tiwari, 1996a discloses- in the case of active solar still, the temperature difference between the evaporating and condensing surfaces are increased by feeding the additional thermal energy from the flat plate collector in to the basin of solar still. The flat plate collector is integrated to the basin of solar still. The water in the basin is circulated through flat plate collector either in a natural circulation mode or a forced circulation mode depending upon the requirement. The connecting pipes are insulated to avoid thermal losses from the hot water in the pipe to ambient during the hot water circulation through it. In an active solar still, the water in the basin is heated directly as well as indirectly through a flat plate collector. The collector should be operated only during sunshine hour. The rise in the temperature of water in the basin mainly depends on number of collectors connected in series.

[See: SOLAR ENERGY (Fundamentals, design, Modeling and applications) by G.N. Tiwari, revised edition 2013].

[0006] Prior art document, US20070193872A1 discloses an integrated solar liquid heater, distiller and pasteurizer system. The Solar heating, distilling, and pasteurizing system of this invention comprises an integrated distillation column-reflector-bracket assembly, a heat storage system of composite construction, and at least one evacuated glass Solar collector having selective absorption. The distillation column Subassembly is filled with the fluid medium to be boiled which flows into the solar vacuum tube collectors where an evaporation process takes place. The height of float valve mechanism is adjustable by means of an adjustable float bracket. The distillation column subassembly collects and concentrates the steam or vapor generated inside the attached evacuated glass Solar collector tubes.

[0007] Another prior art document, US4639293 discloses a solar still wherein the evaporation takes place in partially evacuated tubings which are heated by sunlight. The water to be distilled is supplied from a reservoir vessel which is sealed off after batch loading. The reservoir vessel is elevated above the solar collector. The water is fed into the heater tubing routed through the solar collector by gravity, through an orifice and a heat exchanger condenser. The steam tubing branches off from the heater tubing in the solar collector vertically, and is routed through the heat exchanger-condenser. At this end, it is connected to a vertical tubing of a sizable length that empties into the distilled water reservoir. The exit end of the heater tubing routed through the solar collector is connected to another vertical tubing of a sizable length that emp ties into an overflow tank.

[0008] Still another prior art document,US9908790 discloses the design of an improved house hold solar still with enhanced output and high recovery. The output and recovery are enhanced by ( i ) aligning the top glass and basin so as to maximize the input solar radiation, ( ii ) using North - South reflectors in V trough configuration to further raise the incident radiation, ( iii ) employing metallic condensers on sides to maximize condensation efficiency , ( iv ) using suitably heated and cooled saline water by taking advantage of ambient temperature differential during a day and using such water as feed water and condenser water respectively.

[0009] Still another prior art document,US5672250 discloses a solar seawater desalination system is designed to operate in a self-sustaining manner without the need for any moving parts. Seawater is converted to steam in a solar heat collector panel and the steam is led in a steam pipe through a series of primary cooling chambers where it is condensed by incoming seawater in tanks jacketing the steam tube. The tanks are connected in series between an inlet air-lock regulator and the solar collector panel so that the seawater is caused to flow successively through the tanks from the inlet to the collector panel as make-up water, solely by pressure differentials created in the system by the steam generation. Excessively saline seawater which collects in the collector panel is dumped from the system in a similar manner through an outlet air-lock regulator. Secondary cooling chambers may be provided to condense steam generated from the seawater in the primary cooling chambers by heat received from the steam pipe.

[0010] However, above mentioned references and many other similar references has one or more of the following shortcomings: (a) Less efficient; (b) complex structure; (c) Very expensive; (d) not able to distillate different types of water; (e) not based on solar energy; (f) cannot used for domestic purpose; (g) not feasible for small business & startups and (h) large space occupying etc.

[0011] The present application addresses the above-mentioned concerns and shortcomings (and other similar concerns/shortcomings) with regard to providing an apparatus for water distillation and method thereof using solar energy.

SUMMARY OF THE INVENTION

[0012] In the view of the foregoing disadvantages inherent in the known types of water distillation apparatus or system for purifying water now present in the prior art, the present invention provides an improved apparatus for producing water distillation from either saline, hard, or impure water. As such, the general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new and improved solar energy based apparatus for producing water distillation from either saline, hard, or impure water for which has all the advantages of the prior art and none of the disadvantages.

[0013] It is object of the invention is to provide an apparatus for producing water distillation from either saline, hard, or impure water; A D-plate evacuated collector unit (100) comprising a plurality of D-plate evacuated collector tubes (1); a Reflective board (6); a set of evacuated collector tubes (2 & 4) having copper tube (3 & 5) inside; a high-pressure water rail (7) having a plurality of injectors (8); and a valve (36) fitted on return pipe (37); A Non submerged blackened surface solar still unit (200) comprising an insulated solar still box (9); A plurality small pipe(s) (64) welded on the top of insulated solar still box (9); A plurality of pipe openings (11); an inner surface (10); a distillate compartment (51); a non-distillate compartment (50); a distillate compartment drain (16); a non-distillate compartment drain plug (16); an opening (12); a U-tube distillate pipe (13);an over flow pipe (14) and a welded pipe (65), A Condensing unit (300) comprising an insulated casing (20) having a plurality pipe(s) (21) welded on it; a condenser casing (22); a water tube condenser (23); a condensate trap (48) to collect condensate; an impeller (24) fitted on condenser casing; A steam ventilation system (400) comprising an air-cooled condensing hose (25) having plurality heat transfer fins (25f) on its surface; an insulated hose (26) having connection with condenser hose (14) and impeller (4); an another insulated hose (27) having connection with said air cooled condensing hose (25) and a condensate trap (49); an another hose (28) having connection with the condensate trap (49) and said non-submerged blackened surface solar still unit (200); said steam ventilation system (400) further connects, condensing unit (300) with non-submerged blackened surface solar still unit (200) to produce steam ventilation; Wherein said plurality of D-plate evacuated collector tube(s) (1) of said D-plate evacuated collector unit (100) connected with a plurality of pipe(s) (21) of said condensing unit (300) using plurality flexible hose (17); Wherein a plurality of flexible hoses (18) are connecting said D plate evacuated collector unit (100) with said non-submerged blackened surface solar still unit

(200); Wherein said another hose (28) of said steam ventilation system (400) connected with said opening (12) of said non-submerged blackened surface solar still unit (200) using a welded pipe (65); and Wherein said insulated hose (26) of said steam ventilation system (400) connected with impeller (24) of said condensing unit (300).

[0014] It is another object of the present invention is to provide the apparatus, wherein plurality D-plates (43) are inserted inside respective evacuated collector tubes (41) in a way the said D-plates (43) form a conduit inside the evacuated collector tubes and D-plates are positioned in a way that water flows over the D-Plates forming a thin layer of water.

[0015] Yet another object of the present invention is to provide an apparatus, wherein said D-plates (43) having hollow space (47) below the horizontal plate (44), through which water vapor produced inside the solar still box (9) can be passed to the condenser unit (300) by transferring the heat of water vapor to D-plates, before admitting to the condenser casing.

[0016] Yet another object of the present invention is to provide the apparatus, wherein said Non-submerged blackened surface solar still unit (200) is placed along the same orientation of D-plate evacuated collector tubes.

[0017] Yet another object of the present invention is to provide the method to produce water distillation using the apparatus as claimed in claim 1, wherein said method comprising the following steps: i. Supplying water by said water tube condenser (23) to said copper tube (3) passing through said evacuated collector tube (2) for heating of water (in case of passive mode supply of water from a high head storage while in active mode use of a solar/ electric driven water pump); ii. Supplying hot water of step-i to said high-pressure common water rail (7); iii. Spraying hot water uniformly on plurality hot D-plate(s) (43) via respective injector(s) (8) for evaporation; iv. Supplying non-evaporated water of step-iii on the hot said inner surface (10) of said non-submerged blackened surface solar still unit (200) for evaporation of water; v. Suction of evaporated water vapor inside the said condenser unit (300), produced during step-iii & iv, using said impeller (24); vi. Condensing water vapor of either step-v or produced during step-iii & iv, inside the condenser unit (300) on the surface of said water tube condenser coil (23) in form of water droplets and collection of distillates inside the distillate trap (48). In this stage heating of cooling water also done during condensation process, this preheated water further supplied for the use of step-i; vii. Supplying non-evaporated water vapor of step-vi to air cooled condensing hose (25) for condensation and collection of distillates inside another condensate trap (49); viii. Supplying non-condensed water vapor of step (vii) to non-submerged blackened surface solar still unit (200) via hose (28) and opening (12); ix. Condensation of water vapor produced in step (iv) & coming from hose (28) during step-viii on glass cover (55) and collection of distillates inside the distillate compartment (51); x. Collecting non-evaporated water of step-iv inside non evaporated water compartment (50); and xi. Supplying hot water of step-x to an insulated storage tank (39) after maintaining a certain water level inside the non-evaporated water compartment (50).

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:

Fig.1 depicts exemplary front view of solar distillation system.

Fig.2 depicts different exemplary vital components of solar distillation system.

Fig.3 (a) depicts sectional view of the D-plate evacuated collector tube according to one of the embodiment of present invention.

Fig.3 (b) depicts side view of the D-Plate evacuated collector according to one of the embodiment of present invention.

Fig.3 (c) depicts side view of D-Plate according to one of the embodiment of present invention.

Fig.3 (d) depicts top view of D-Plate according to one of the embodiment of present invention.

Fig. 4 (a) depicts sectional view of D-plate evacuated collector tube according to one of the embodiment of present invention.

Fig. 4 (b) depicts a view of D-plate evacuated collector tube assembled on reflective board along with flexible hoses connected on the both ends of evacuated collector tube according to one of the embodiments of present invention.

Fig. 4 (c) depicts sectional view of D-Plate evacuated collector tube along with flexible hoses connected on the both ends of evacuated collector tube and fitment of water pressure rail & injection nozzle with hose and D-Plate evacuated collector tube according to one of the embodiments of present invention.

Fig. 4 (d) depicts exemplary sectional view of reflective board showing its curved surface.

Fig.5 depicts exemplary sectional view of solar distillation system in passive mode.

Fig.6 depicts exemplary sectional view of solar distillation system in active mode.

Fig.7 depicts the flow chart of passive mode operation of said distillation apparatus.

Fig.8 depicts the flow chart of active mode operation of said distillation apparatus.

DETAILED DESCRIPTION OF THE INVENTION

[0019] In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that the embodiments may be combined, or that other embodiments may be utilized and that structural and logical changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims and their equivalents.

[0020] References will now be made in detail to the exemplary embodiment of the present disclosure. Before describing the detailed embodiments that are in accordance with the present disclosure, it should be observed that the embodiments reside primarily in combinations arrangement of the system according to an embodiment herein and as exemplified in Figs. 1-6.

[0021] In the following description, for the purpose of explanation, numerous specific details are set forth in order to provide a thorough understanding of the arrangement of the system according to an embodiment herein. It will be apparent, however, to one skilled in the art, that the present embodiment can be practiced without these specific details. In other instances, structures are shown in block diagram form only in order to avoid obscuring the present invention.

[0022] The main embodiments of the present invention are to provide an apparatus and method for producing distilled waterusing a plurality D-plate evacuated collector tube & non submerged blackened surface solar still. Fig. 1 depicts an exemplary view of water distillation apparatus, the said apparatus mainly comprises of a D-plate evacuated collector unit (100), a non-submerged blackened surface solar still unit (200), a condenser unit (300) and a steam ventilation system (400).

[0023] Said D-plate evacuated collector unit (100) further comprises of a plurality D-plate evacuated collector tubes (1) which are tightly assembled on a reflective board (6) using plurality brackets (60) and plurality nut-bolt assemblies (61). At the bottom of each D-plate evacuated collector tube flexible hoses (18) are mounted using a plurality rubber seal (19). Similarly, at the top of each evacuated collector tube (1) plurality perforated flexible hoses (17) mounted using plurality rubber seal (19). A common high-pressure water rail (7) having plurality water injectors (8), the said water injectors (8) are passing through the perforation (17h) of plurality perforated flexible hoses (17) and inserted few millimeters inside each D plate evacuated collector tube (1). All the said injectors spray water inside the D-plate evacuated collector tube (1) for evaporation. (2) & (4) are evacuated collector tubes which are fixed on the reflective board (6) in a similar way to D-plate evacuated collector tubes. Evacuated collector tubes (2) & (4) having copper tubes (3) & (5) inside respectively. Evacuated collector tube (2) and its inside copper tube (3) supplies preheated water to high pressure common water rail (7), while copper tube (5) connected with a return line having a valve (36). Evacuated collector tube (4) and its inside copper tube (5) further heats the water supply which is returning via the return line (37). Return line further connects with supply line of copper tube (3).

[0024] Said non-submerged blackened surface solar still unit (200) further comprises of an insulated solar still box (9) having its inner surface (10) coated with a solar irradiance absorbing material. Plurality hollow pipes (64) welded at the top of solar still box (9), which creates plurality openings (11) inside the solar still box. Another pipe (65) welded at the top right side of the solar still box (9) which creates another opening (12) inside the solar still box. A partition (38) separates the inner bottom surface of solar still box into two different compartments [non-distillate compartment (50) and distillate compartment (51)]. Drain valves (15) & (16) connected at the bottom of non-distillate compartment (50) and distillate compartment (51) respectively for the cleaning or draining the fluid inside. A U-tube pipe (13) connected with distillate compartment (51) for the collection of distillates from said compartment. U-tube also maintain acertain level of distillate inside the distillate compartment for preventing atmospheric air inside the solar still box (9). Similarly, another pipe (14) connected with non-distillate compartment (50), which supplies unevaporated hot water to an insulated storage tank (39) after maintaining a certain water level inside the non distillate compartment (50). Pipe (14) positioned in a way that it prevents over flowing of non-evaporated hard water from non-distillate compartment (50) to distillate compartment (51) also it prevents tank air inside the solar still box. The solar still box is covered with a transparent glass cover (55), which covers the solar still box in a leakproof way. Glass cover (55) also used for condensation of water vapor produced inside the solar still box. The glass cover (55) remains parallel with inner surface (10). The inner surface (10) never remains submerged into the water only thin layer of water flows over the inner surface (10). The inner surface (10) never remains submerged into the water that is why we are calling this unit non submerged blackened surface solar still.

[0025] Another end of plurality flexible hoses (18) which are connected with plurality D plate evacuated collector tubes (1) further connects with respective welded pipe (64) of solar still box (9). In this way D-plated evacuated collector unit (100) integrates with non submerged blackened surface solar still unit (200) using plurality flexible hoses (18) and rubber seal (19). The non-evaporated water from each D-plate evacuated collector tube enters into the non-submerged blackened surface solar still unit via plurality flexible hoses.

[0026] Said condenser unit (300) further comprises of an insulating casing (20) having plurality pipes (21) equidistantly welded on it,a condenser casing (22) which is further welded with an insulating casing (20). A water tube condenser coil (23) fixed inside the condenser casing to condense the water vapors on its coiled surface. A condensate trap (48) attached at the bottom of condenser casing (22) to collect the condensate trickling from the condenser coil.

[0027] Another ends of plurality perforated flexible hoses (17) which are connected at the top of plurality D-plate evacuated collector tubes (1) using plurality rubber seals (19), further coupled with respective plurality welded pipes (21) of condenser casing (22). In this way D plated evacuated collector unit (100) integrates with condenser unit (300) using plurality perforated flexible hoses (17) and plurality rubber seals (19). The steam produced inside the solar still box and plurality D-plate evacuated collector tubes enters inside the condenser unit via plurality perforated flexible hoses (17) for the condensation of water vapors.

[0028] Said steam ventilation system (400) further comprises of an air-cooled condensing hose (25) having plurality heat transfer fins (25f) covered on its surface. An impeller (24), its one end connected with condenser casing (22) of condenser unit (300) (in a leakproof way) and another end coupled with an insulated hose (26). The insulated hose (26) further connected with the inlet side of air-cooled condensing hose (25). The non-condensed water vapor of condensing unit further forced by the impeller to the air-cooled condensing hose via insulated hose (26) for condensation. Exit end of air-cooled condensing hose (25) connected with another insulated hose (27) which is further connected with another condensate trap (49). The condensed water vapors inside the air-cooled condensing hose (25) percolate via insulated hose (27) and collected inside the condensate trap (49). Through condensate trap (49) condensate can be collected through a drain pipe. Another end of condensate trap (49) connected with still another insulated hose (28), which can be further connected with the welded pipe (65) of non-submerged blackened surface solar still unit (200). The non condensed water vapor of air-cooled condensing hose enters into the non-submerged blackened surface solar still unit via an opening (12) through insulated hose (28).

[0029] The steam ventilation system (400) connects the condenser unit (300) with non submerged blackened surface solar still unit (200). Connection provided by the steam ventilation system (400) produces a steam ventilation inside the apparatus. The vapors of water circulated inside the apparatus till it has not been condensed. The impeller of steam ventilation system impels water vapors produced inside the D-plate evacuated collector tubes & solar still box and condensed them inside the condenser unit using water tube condenser coil. The non-condensed water vapors from the condenser box further propelled to the air cooled condensing hose for condensation. Still non-condensed water vapors of air-cooled condensing hose further enters into the solar still box where some percentage of water vapor gets condensed on solar still box's glass cover and remaining vapors again enters into the condenser unit via plurality D-plate evacuated collector tubes. It is noticeable that the water vapors which are producing inside the solar still box, entering into the condenser unit via plurality D-plate evacuated collector tubes.

[0030] The impeller (24) of steam ventilation system (400) also produces a small amount of negative pressure (below atmospheric pressure) inside the D-plate evacuated collector tubes

& non-submerged blackened surface solar still unit, this reduction in pressure reduces the boiling temperature of water and water can get evaporated easily. But there is slightly more (above atmospheric)pressure remains inside the condenser box during the operation of apparatus.

[0031] Said hard water distillation apparatus can be operated in two different active and passive modes using a single apparatus. Only few settings are required to convert apparatus from active mode to passive mode. In case of passive mode, hard water will be supplied from a high head storage tank or supply. In passive mode apparatus operation, there will be no need of water pump (56) and return line (37). In passive mode return line can be closed via plurality valves (36) & (57). While in active mode water can be supplied from a low head storage tank or supply. In active mode operation of apparatus, a solar electricity driven water pump (56) will be required to supply the water to common high-pressure water rail. The return line will also be activated in this mode of apparatus operation.

[0032] In case of passive mode high head water will be supplied to the apparatus via a supply line (29), supply line (29) will further supply water to another supply pipe (30) [supply pipe (30) having less pipe diameter then the supply line (29)] and then to still another supply line (32) [30 & 32 have same pipe diameter]. The difference in the pipe diameter (diameter of 29 & 30) is provided to provide a high-pressure water supply to the apparatus. In case of active mode water will be supplied to the apparatus via a supply line (31) to the supply line (32), wherein supply line (31) and supply line (32) having same pipe diameter. Also, in case of passive mode valve (35) remains closed while valve (34) will remain open (in active mode reverse valve positions will be used). The supply line (32) finally connects with the inlet of condenser coil (23) and supply water either from high or low head.

[0033] The size of return line should be 1 / 3rd the size of the supply to common high-pressure water rail (7) and the size of storage tank water supply to supply line (33) should be half (1/2) the size of supply line (33).

[0034] Fig. 2 showing distinct views of the main embodiments of apparatus which are:a D plate evacuated collector unit (100); a condensing unit (300); a non-submerged blackened surface solar still unit (200) and a steam ventilation system (400). Said main embodiments (100), (200), (300) & (400) furthercan integrate together to form an apparatus described in Fig.1.

[0035] Fig. 3a & 3b are showing two different exemplary views of D-plate evacuated collector tube (1) which is one of the embodiment of present invention. D-plate evacuated collector tube comprises of an evacuated collector tube (41) which is opened at the both of ends. The inner tube of evacuated collector tube (41) coated with a solar irradiance absorbing material (42). A D-plate (43), which is one of the vital component of D-plate evacuated collector tube, inserted inside the collector tube (41). Said D-plate comprises of a flat plate (44) which is welded with a half round sheet (46). After the joining of flat plate (44) and half round sheet (46), both creates a hollow space (47) beneath the flat plate. This hollow space allows to pass the maximum percentage of water vapor from solar still box to condenser unit. During the passing of hot water vapors, water vapors transfers its heat to the flat plates (44) and flat plates gets more heated for the fast evaporation of water flowing over the flat plates. D-plates (43) are essentially required to position in a way that flat plate remains in horizontal position inside the collector tube. Such position of D-plates inside the collector tubes distribute water evenly over the flat plate. The half round sheet also extruded [represented by numeral (45)] at both ends to prevent contact of water with evacuated collector tubes. Visually, top portion of the D-plates are like a conduit for the flow of water which has to be evaporated on the D-plates. Collector tubes (41) absorbs solar irradiance and increase the temperature of D-plates placed inside. When water from the plurality injectors being injected on the respective hot flat plate, water gets evaporated very quickly. D-plate evacuated collector tubes always remains at some orientation (for the collection of maximum solar irradiance), that is why water on the D-plates flows by the gravity effect. The D-plates can be made of using good conductive material having plated with rust-free materials to prevent D plates from corrosion.

[0036] Fig. 3c &3d are represents respective exemplary side and top views of D-plate (43) which has already been describe in Fig.3a & 3b. (refer Fig.3a & 3b for detailed description).

[0037] Fig. 4a represents a sectional view of D-plate evacuated collector tube (1), (NBs) representing the non-coated inner surface of evacuated collector tubes, which will be further covered by the plurality rubber seal (19). (Bs) representing the length of solar irradiance coating of evacuated collector tube. The collector tube made of two glass tubes by inserting one into the other and keeping in-between area evacuated. The coating is done on the inner surface of inner glass tube.

[0038] Fig. 4b representing assembly of D-plate evacuated collector tube on the reflective board (6). The flexible hose (18) & perforated hose (17) are fitted at the respective ends of D plate evacuated collector tube as shown in the exemplary diagram (Fig. 4b). Plurality rubber brackets (60) and plurality nut-bolt assemblies (61) are used to assemble the plurality D-plate evacuated collector tubes tightly on the reflective board.

[0039] Fig. 4c representing the way the injector (8) is passing through the perforated flexible hose (17) and positioned near to the starting end of D-plate (43).

[0040] Fig. 4d showing sectional view of reflective board (6) having plurality curves (63) crafted on its surface. (62) are the plurality holes for passing the nut-bolt assemblies (61) during the assembly of D-plate evacuated collector tubes on the reflective board (6). All the curve(s) (63) are coated with a solar irradiance reflective material so that maximum irradiance incident on curved surface can project on D-plate evacuated collector tube (1).

[0041] Fig. 5 & 6 are illustrating respective exemplary side views of passive and active mode arrangements of said water distillation apparatus, according to one of the embodiments of present invention. As described earlier, samewater distillation apparatus can be used for the both modes of operation. If the water is available at high head (or high head supply) then passive mode is most suitable, but if supply or availability of hard water is not at high head then passive mode operation of apparatus can be employed. In active mode apparatus operation, an electric or solar electricity powered water pump is essentially required to supply hard water to common high-pressure water rail at high pressure. While in passive mode, due to high head [and combination of supply lines (29) & (30)] there is already a pressure in the water supply so no need of water pump. There is a return line (37) on apparatus, which remains closed with the help of valves (36) & (57) during the passive mode operation (in Fig. 5, return line and valves are not shown) (refer Fig.1). The non-evaporated water from non distillate compartment (50) of solar still box, drain into an insulated storage tank (39) after maintaining a certain level of water inside the non-distillate compartment. After the sunset, storage tank fills very fast and a float (53) automatically blocks the supply of water to the common high-pressure water rail via a float operated valve (52) (passive mode). For the next day of apparatus operation (passive mode) storage tank needs to empty for the uninterrupted supply of water to the common high-pressure water rail.

[0042] In case of active mode an electric pump (or solar electric pump) integrated with the supply line (33). The pump, pumps the water supply coming from the condenser coil. In active mode apparatus operation, return line remains live by opening the valves (36) & (57). Via return line water returns back to pump supply but return supply initially heated by an evacuated collector tube (4) & a copper tube (5) arrangement. In this way more preheated water supplied to the common high-pressure water rail. At sun set, pump automatically stops functioning and apparatus automatically stops its working. But, if storage tank fill above a defined level during the presence of solar irradiance, the float (53) automatically reduces the main supply of hard water by 50% using a valve (58). Same time another valve (59) which is integrated with float mechanism, opens parallelly with the partial closing of valve (58) and compensate the 50% supply of supply line. A water strainer (40) also being used to filter the tank water supply to the main supply line (33). (Refer Fig. 1 for the detailed description of the water distillation apparatus).

[0043] Fig. 7& Fig. 8 are representing exemplary flow chart of the functioning of water distillation apparatus in passive and active mode respectively. Fig. 7 showing the flow chart of the functioning of passive mode operation of apparatus according to one of the embodiments of present invention. Said method of producing water distillation comprising the following steps: Initially hard water being supplied from a high head to a condenser coil (step-701), a preheating of hard water is being done inside the condenser coil by the heat exchange process during condensation process (step-702), preheated water of step-702 further supplied to the evacuated collector tube & copper tube arrangement for more heating (step 703), heated water of step-703 further supplied to a common high pressure water rail (step 704), high pressure water of step-704 further supplied to plurality injectors (step-705), injection of water done on plurality D-plate evacuated collector tubes for evaporation (step 706), non-evaporated water of step-706 further supplied to the non-submerged blackened surface solar still for evaporation (step-707), water vapors of step-706 and step-707 further impelled via an impeller (step-706a),supply of water vapor of step-706a to the condenser for condensation (step-708), non-condensed water vapors of step-708 further propelled via impeller to an air-cooled condenser hose for condensation (step-709), supplying non condensed water vapors of step-709 to non-submerged blackened surface solar still, collection of water distillation condensed on glass cover of non-submerged blackened surface solar still (step-707a), supply of non-evaporated water of step-707 to an insulated storage tank for domestic or other uses (step-707b), collection of water distillation condensed on water tube condenser coil (step-708a), collection of water distillation of step-709 inside a condensate trap (step-709a),final collection of water distillation of step-709a (step-709b). Fig. 8 showing the flow chart of active mode operation of apparatus according to one of the embodiments of present invention.Said mode of water distillation comprising the following steps: Initially hard water being supplied from a low head to a condenser coil (step-801), preheating of hard water is being done inside the condenser coil by the heat exchange process during condensation of water vapors (step-802), preheated water of step-802 further pumped via a pump to an evacuated collector tube & copper tube arrangement for more heating (step-803), heated water of step-803 further supplied to a common high pressure water rail (step-804), high pressure water of step-804 further supplied to plurality injectors (step-805), some water of step-804 also bypass via a return line by passing the water supply through an another evacuated collector tube & copper tube arrangement (for more heating of water) and then connecting this supply with the exit supply of step-802 (step-804a), injection of water done on plurality D-plate evacuated collector tubes for evaporation (step-806), non-evaporated water of step-806 further supplied to the non-submerged blackened surface solar still for evaporation (step-807), water vapors of step-806 and step-807 further impelled via an impeller (step-806a),supply of water vapor of step-706a to the condenser for condensation (step-808), non-condensed water vapors of step-808 further propelled via impeller to an air cooled condenser hose for condensation (step-809), supplying non-condensed water vapors of step-809 to non-submerged blackened surface solar still, collection of water distillation condensed on glass cover of non-submerged blackened surface solar still (step-807a), supply of non-evaporated water of step-807 to an insulated storage tank (step-807b), supply of step 807b water along with the exit supply of step-802 (step-807c), collection of water distillation condensed on water tube condenser coil (step-808a), collection of water distillation of step 809 inside a condensate trap (step-809a), final collection of water distillation of step-809a (step-809b).

[0044] The performance of the water distillation apparatusof the present invention is also checked and analyzed by performing some experiments. The apparatus having 9 evacuated collector tubes (1.2 meters long & 47 milli meters inner diameter) having a D-plate inside each tube, while two more evacuated collector tubes are for preheating the water supply. The said non-submerged blackened surface solar still having surface area of 1-meter(width) xO.5 meter (height). Hard water having300 to 1500 ppm value water (free from solid impurities) fed to the apparatus for distillation. The used evacuated collector tubes can produce temperature in range of 75 to 165 degree centigrade inside the evacuated collector tube, while the D-plates are attaining temperature in the range of 50 to 120 degree centigrade. Also, the non-submerged blackened surface solar still having its inner surface temperature in the range of 60 to 90 degree centigrade. A thin layer(0.4 to 0.8 mm thick) of water has been maintained on each D-plate by controlling the injection amount of water. A low atmospheric pressure (0.8 to 0.9 bar) has been maintained inside the D-plate evacuated collector tubes and non submerged blackened surface solar still unit by an impeller to lower the boiling temperature of water flowing inside. The water entering into the common high-pressure water rail is about 50 to 60 degree centigrade (in passive mode temperature of water is 5 degree less), while 45 to 55-degree centigrade temperature range water (in passive mode temperature of water is 2 to 4 degree less) is being injected on all the D-plates. The hard water which is being fed to the condenser coil is at 20 to 25 degree centigrade. The overall output from the apparatus (for a clear sunny day) in passive mode is received in the range of 5 to 7 liters while it is 6 to 9 liters in case of active mode. Further, the experiments also carried out by increasing more numbers of D-plate evacuated collector tubes and the surface area of non-submerged blackened surface solar still,higher distillate yieldis achieved.The present water distillation apparatus having capability to produce 99% purewater distillation which is useful for electrical, automotive &

laboratory applications.The produced distilled water is also check by checking the pH, conductivity, and softness of the water. After the sunset D-plate(s) and inner surface of non submerged blackened surface solar still automatically turn out to be drain off from water which prevents algae formation inside the said embodiments. The apparatus for water distillationof the present invention can be of any size, which can produce the distilled water according to the requirements. The distilled water has various application or uses, such as it can be used in automobiles for cleaning and cooling down the engines; for laboratory experiments; as universal solvent in cosmetics products; canning fruits and vegetables; in hospitals; for sanitization of the places; for wet batteries & other electrical applications and brewing beer or alcohol products.

[0045] It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-discussed embodiments may be used in combination with each other. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description.

[0046] The benefits and advantages which may be provided by the present invention have been described above with regard to specific embodiments. These benefits and advantages, and any elements or limitations that may cause them to occur or to become more pronounced are not to be construed as critical, required, or essential features of any or all of the embodiments.

[0047] While the present invention has been described with reference to particular embodiments, it should be understood that the embodiments are illustrative and that the scope of the invention is not limited to these embodiments. Many variations, modifications, additions and improvements to the embodiments described above are possible. It is contemplated that these variations, modifications, additions and improvements fall within the scope of the invention.

Claims (5)

CLAIMS:

1. An apparatus for water distillation comprising of; A D-plate evacuated collector unit (100) comprising a plurality of D-plate evacuated collector tubes (1); a Reflective board (6); a set of evacuated collector tubes (2 & 4) having copper tube (3 & 5) inside; a high-pressure water rail (7) having a plurality of injectors (8); and a valve (36) fitted on return pipe (37); A Non-submerged blackened surface solar still unit (200) comprising an insulated solar still box (9); a plurality small pipes (64) welded on the top of insulated solar still box (9); a plurality of pipe openings (11); an inner surface (10); a distillate compartment (51); a non-distillate compartment (50); a distillate compartment drain (16); a non-distillate compartment drain plug (16); another welded pipe (65) having opening (12); a U-tube distillate pipe (13) and an overflow pipe (14); A partition (38) wherein said partition dividing solar still box lower part into two compartments non-distillate compartment (50) &distillate compartment (51); A Condensing unit (300) comprising an insulated casing (9) having a plurality pipes (21) welded on it; a condenser casing (22); a water tube condenser (23); and a condensate trap (48) to collect condensate; A steam ventilation system (400) comprising an impeller (24); an air-cooled condensing hose (25) having plurality heat transfer fins (25f) on its surface; an insulated hose (26) connected with impeller (24) andair-cooled condensing hose (25); another insulated hose (27) connected with air-cooled condensing hose (25) and a condensate trap (49); yet another insulated hose (28) connected with condensate trap (49) and welded pipe (65)of non submerged blackened surface solar still unit (200); A steam ventilation system (400) further connects, condensing unit (300) with non submerged blackened surface solar still unit (200) to produce steam ventilation and negative pressure inside said plurality D-plate evacuated collector tubes (1) andsaid insulated casing (9); Wherein said plurality of injectors (8) are implanted inside respective perforation (17h) of a flexible hose (17); Wherein a plurality of flexible hoses (18) are connecting said D-plate evacuated collector unit (100) with said non-submerged blackened surface solar still unit (200); and Wherein said non-submerged blackened surface solar still unit (200) is placed along the same orientation of D-plate evacuated collector unit (100).

2. The apparatus as claimed in claim 1, wherein said plurality of D-plates (43) are inserted inside their respective evacuated collector tubes (41) in an order that flat plate of D plates (43) remains in horizontal position for the even distribution of thin water layer.

3. The apparatus as claimed in claim 1, wherein said plurality of D-plates (43) having a hollow space (47) for passing the major percentage of water vapor produced inside the non submerged blackened surface solar still unit (200) to the condenser unit (300) and also to heat-up the D-plates via hot water vapor.

4. The apparatus as claimed in claim 1, wherein plurality D-plate evacuated collector tubes (1) are equidistantly placed over the respective curves (63) of reflective board (6) using plurality brackets (60) and plurality nut-bolt assemblies (61).

5. A method to produce distilled waterusing the apparatus of claim 1, wherein said method comprising the following steps: i. Supplying hard water by said water tube condenser (23) to said copper tube (3) passing through said evacuated collector tube (2) for heating of water (in case of passive mode supply of water from a high head storage while in active mode use of a solar/ electric driven water pump); ii. Supplying hot water of step-i to said high-pressure common water rail (7); iii. Spraying hot water uniformly on hot plurality D-plate(s) (43) via respective injector(s) (8) for evaporation; iv. Supplying non-evaporated water of step-iii on the hot said inner surface (10) of said non-submerged blackened surface solar still unit (200) for evaporation of water; v. Suction of evaporated water vapor inside the said condenser unit (300), produced during step-iii & iv, using said impeller (24); vi. Condensing water vapor of either step-v or produced during step-iii & iv, inside the condenser unit (300) on the surface of said water tube condenser coil (23) in form of water droplets and collection of distillates inside the distillate trap (48). In this stage heating of cooling water also done during condensation process, this preheated water further supplied for the use of step-i; vii. Supplying non-evaporated water vapor of step-vi to air cooled condensing hose (25) for condensation and collection of distillates inside another condensate trap (49); viii. Supplying non-condensed water vapor of step (vii) to non-submerged blackened surface solar still unit (200) via hose (28) and opening (12) of welded pipe (65); ix. Condensation of water vapor produced in step (iv) & coming from hose (28) during step-viii on glass cover (55) and collection of distillates inside the distillate compartment (51); x. Collecting non-evaporated water of step-iv inside the non-evaporated water compartment (50); xi. Supplying hot water of step-x to an insulated storage tank (39) after maintaining a certain water level inside the non-evaporated water compartment (50); and xii. Collection of distillates via said U-tube (13) collected during step (ix).