US20060191530A1

US20060191530A1 - Soalr energy water heater

Info

Publication number: US20060191530A1
Application number: US11/069,626
Authority: US
Inventors: Jun Xia; Zhu Xia
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-02-28
Filing date: 2005-02-28
Publication date: 2006-08-31

Abstract

A solar energy water heater includes a water pipe and a plurality of solar heat units transversely extended from the water pipe, wherein each solar heat unit includes a heat collecting tube is adapted for heating up the water within the heat collecting tube and a heat transferring tube disposed in the heat collecting tube to define a water conduit. The heat transferring tube has a water channel and an outer opening end extended towards to an outer closed end of the heat collecting tube to communicate the water channel with the water conduit of the heat collecting tube such that the water is guided to flow from the water inlet to each of the solar heat units to circularly flow between the water conduit and the water channel thereof so as to substantially heat up the water before flowing out at a water outlet of the water pipe.

Description

BACKGROUND OF THE PRESENT INVENTION

1. Field of Invention
The present invention relates to a water heater, and more particularly to a solar energy water heater, wherein the water is guided to circularly flow within each of heat collecting tubes to substantially heat up the water therewithin by solar energy while being cost effective.
2. Description of Related Arts
Conventional water heaters mainly utilize gas or electricity as a power source to heat up water for domestic or industrial purpose. A conventional water heating system comprises a water heater having a water outlet and a water inlet connecting with a water source in such a manner that the water at the room temperature is heated up by the water heater to reach a preset temperature.
Water heater utilizing solar energy as the power source has been developed to resolve the problems of potential energy crises or shortages. Those solar energy water heaters no doubt meet the ever-increasing demand of environmental protection and ‘clean energy source’ from people all over the world. Yet they have several drawbacks.
The solar energy water heater comprises a heat collecting tube defining a water passage therein wherein water is guided to flow into the heat collecting tube in such a manner that the heat collecting tube collects the solar energy and heats up the water within the water passage. Accordingly, the heat collecting tube is made of glass coated with a solar heat absorbing layer such that when the heat collecting tube is exposed under the sunlight, the solar heat absorbing layer absorbs the solar energy and transfers into the water passage to heat up the water therewithin. It is worth to mention that the hot water is collected at the upper portion of the heat collecting tube to a water tank while the cool water is remained at the lower portion of the heat collecting tube such that the efficiency of the conventional solar energy water heater is very low.
Furthermore, the water system cannot be normally functioned during the heat exchange of the water. In other words, when using the hot water in the water tank, a valve of the solar energy water heater is closed to stop the water to enter into the heat collecting tube. Therefore, the solar energy water heater cannot be functioned under the normal water pressure of the water system since the water must be collected within the heat collecting tube for heat exchange.
In addition, the heat collecting tube, having an upper opening end and a bottom sealing end, must be positioned in an inclined manner that the water is guided to flow into the water passage at an upper opening end of the heat collecting tube. Once the water is heated up, the hot water flows out of the heat collecting tube at the upper opening end thereof while cool water is filled towards the bottom sealing end. Therefore, the installation of the solar energy water heater is limited by the position of the heat collecting tube that the heat collecting tube must be located at an optimized orientation under the sunlight. It is worth to mention that the temperature of the heat collecting tube is relatively high in order to heat up the water therewithin such that when the cool water is filled into the heat collecting tube, the glass made heat collecting tube will be cracked due to the sudden change of temperature. In other words, the manufacturer should take account of the quality of the heat collecting tube to prevent the crack thereof which will highly increase the manufacturing cost of the solar energy water heater. Once the heat collecting tube is broken, the entire solar energy water heater cannot be functioned.

SUMMARY OF THE PRESENT INVENTION

A main object of the present invention is to provide a solar energy water heater, wherein the water is guided to circularly flow within each of the heat collecting tubes to substantially heat up the water therewithin by solar energy while being cost effective.
Another object of the present invention is to provide a solar energy water heater, wherein the heat collecting tubes are radially extended from a water pipe such that the water flows from a water inlet of the water pipe to a water outlet thereof through each of the heat collecting tubes to enhance the heat exchange process.
Another object of the present invention is to provide a solar energy water heater, wherein the water system can be normally function during the operation of the solar energy water heater because the water flows into the water pipe at the water inlet and out of the water pipe at the water outlet normally under the water pressure of the water system.
Another object of the present invention is to provide a solar energy water heater, which can be located at any position to optimize the sun orientation for effectively transforming solar energy into heat energy.
Another object of the present invention is to provide a method of heating water by solar energy while being cost effective.
Another object of the present invention is to provide a solar energy water heater, which does not involve complicated mechanical components so as to minimize the manufacturing cost and the ultimate selling price of the present invention.
Accordingly, in order to accomplish the above objects, the present invention provides a solar energy water heater, comprising:
a water pipe having a water inlet and a water outlet and defining a water passage therebetween for guiding water to flow from the water inlet to the water outlet; and
a plurality of solar heat units transversely and spacedly extended from the water pipe to communicate with the water passage thereof, wherein each of the solar heat units comprises:
a heat collecting tube having an outer closed end and an inner opened end extended from the water pipe, wherein the heat collecting tube is adapted for collecting solar energy and transforming the solar energy into heat energy to heat up the water within the heat collecting tube; and
a heat transferring tube, which is made of heat conductive material, disposed in the heat collecting tube to define a water conduit between the heat collecting tube and the heat collecting tube, wherein the heat transferring tube has a water channel and an outer opening end extended towards to the outer closed end of the heat collecting tube to communicate the water channel with the water conduit of the heat collecting tube such that the water is guided to flow from the water inlet to each of the solar heat units to circularly flow between the water conduit and the water channel thereof so as to substantially heat up the water at each of the solar heat units before flowing out at the water outlet of the water pipe.
These and other objectives, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a solar energy water heater according to a first preferred embodiment of the present invention.
FIG. 2 is a sectional view of the solar heat unit of the solar energy water heater according to the above first preferred embodiment of the present invention.
FIG. 3 is a schematic view of a solar energy water heater according to a second preferred embodiment of the present invention.
FIG. 4 is a schematic view of the solar heat unit of the solar energy water heater according to a third preferred embodiment of the present invention.
FIG. 5 is a partially exploded perspective view of the solar energy water heater according to the above third preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1 of the drawings, a solar energy water heater according to a first preferred embodiment of the present invention is illustrated, wherein the solar energy heater comprises a water pipe 10 and a plurality of solar heat units 20.
The water pipe 10 has a water inlet 11 and a water outlet 12 and defines a water passage 13 therebetween, wherein the water pipe 10 is operatively communicating with a water source S such that water from the water source S flows into the water pipe 10 at the water inlet 11 and flows out at the water outlet 12. A heat insulating layer 14 is enclosing an outer surface of the water pipe 10 for preventing heat loss of the water passing along the water passage 13. In other words, the water pipe 10 not only guides the water to flow to each of the solar heat units 20 but also conserves the heat energy of the water when the water is heated up by the solar heat units 20.
The solar heat units 20 are transversely and spacedly extended from the water pipe 10 to communicate with the water passage 13 thereof, wherein each of the solar heat units 20 comprises a heat collecting tube 21 and a heat transferring tube 22.
Each of the heat collecting tubes 21 has an outer closed end 211 and an inner opened end 212 extended from the water pipe 10, wherein the heat collecting tube 21 is adapted for collecting solar energy and transforming the solar energy into heat energy to heat up the water within the heat collecting tube 21.
Each of the heat transferring tubes 22, which is made of heat conductive material such as copper, disposed in the respective heat collecting tube 21 to define a water conduit 210 between the heat collecting tube 21 and the heat collecting tube 22, wherein the heat transferring tube 22 has a water channel 220 and an outer opening end 221 extended towards to the outer closed end 211 of the heat collecting tube 21 to communicate the water channel 220 with the water conduit 210 of the heat collecting tube 21 such that the water is guided to flow from the water inlet 11 to each of the solar heat units 20 to circularly flow between the water conduit 210 and the water channel 220 thereof so as to substantially heat up the water at each of the solar heat units 20 before flowing out at the water outlet 12 of the water pipe 10.
As shown in FIG. 1, each of the solar heat units 20 is perpendicularly extended from the water pipe 10 at a direction wherein the water is guided to flow from the water inlet 11 to each of the solar heat units 20 for heat exchange and to flow out at the water outlet 12.
As shown in FIG. 2, each of the heat collecting tube 21 comprises an outer tubular member 213, an inner tubular member 214 sealed therein in end-to-end manner, and a solar energy collecting agent 215 sealedly provided between the outer and inner tubular members 213, 214, wherein the water conduit 210 is formed between the inner tubular member 214 and the heat transferring tube 22 receiving therein such that the solar energy collecting agent 215 is adapted for collecting the solar energy to heat up the water within the inner tubular member 214. Preferably, each of the outer and inner tubular members 213, 214 is made of glass adapted for the sunlight passing therethrough to reach the solar energy collecting agent 215.
Each of the heat transferring tubes 22 is made of heat conductive material, such as copper, such that the heat energy from the respective heat collecting tube 21 is adapted to conductively transfer into the water channel 220 through the heat transferring tube 22 for heating up the water within the water channel 220. In other words, the water within each of the solar heat units 20 is heated up twice at the time when the water pass through the water conduit 210 and the water channel 220. It is worth to mention that when the cool water suddenly flows to the heat collecting tube 21 which is relatively hot, the heat collecting tube 21 may be cracked due to the sudden change of temperature. Therefore, the water is preheated along the heat transferring tubes 22 to prevent the crack of the heat collecting tube 21 when the water flows to the water conduit 210.
The solar energy heater further comprises a plurality of water guiders 30 spacedly disposed in the water passage 13 of the water pipe 10 to align with the solar heat units 20 respectively, wherein each of the water guiders 30 has a guiding passage 31 extended to an inner end 222 of the respective heat transferring tube 22 for guiding the water to flow into the water channel 220 from the water passage 13 such that the water flows to the water conduit 210 from the water channel 220 through the outer opening end 221 of the heat transferring tube 22 and back to the water passage 13 of the water pipe 10 through the inner opened end 212 of the solar collecting tube 21, as shown in FIG. 1.
In other words, the water from the water source flows into the water inlet 11 of the water pipe 10 through each of the solar heat units 20 and exits at the water outlet 12 of the water pipe 10. Accordingly, the water is guided to flow into the water channel 220 of the respective heat transferring tube 22 via the water guider 30 to the water conduit 210 of the respective heat collecting tube 21 when the water flows to each of the solar heat units 20, such that the water can be substantially heated up twice at each of the solar heat units 20.
It is worth to mention that the solar energy water heater of the present invention can be incorporated with the conventional water system having a predetermined water pressure such that the water at the water source S is pumped to the water pipe 10 at the water inlet 11 to each of the solar heat units 20. In addition, the solar energy water heater of the present invention can be incorporated with the conventional water system without water pressure, such that the water flows from the water inlet 11 to the water outlet 12 through each of the solar heat units 20 by gravity. In other words, the water flows from the solar heat unit 20 at the upper position to the solar heat unit 20 at the bottom position by gravity. Furthermore, the user is able to select how many the solar heat units 20 is needed to heat up a predetermined volume of water for usage. Therefore, the user can set up the solar energy water heater by simply assembling the solar heat units 20 to the water pipe 10. In other words, even one of the solar heat units 20 is broken, the solar energy water heater can still properly function and the user is able to replace the broken solar heat units 20 as well.
As shown in FIG. 3, a solar energy water heater of a second embodiment illustrates an alternative mode of the first embodiment of the present invention, wherein the solar heat units 20′ are formed in pairs and are transversely and spacedly extended from the water pipe 10′ to communicate with the water passage 13′ thereof. Each of the solar heat units 20′, having the same structure of the first embodiment, comprises a heat collecting tube 21′ and a heat transferring tube 22′.
The water pipe 10′ is operatively communicating with a water source S such that water from the water source S flows into the water pipe 10′ at the water inlet 11′ and flows out at the water outlet 12′. A heat insulating layer 14′ is enclosing an outer surface of the water pipe 10 for preventing heat loss of the water passing along the water passage 13′.
Each of the heat collecting tubes 21′ has an outer closed end 211′ and an inner opened end 212′ extended from the water pipe 10′, wherein the heat collecting tube 21′ is adapted for collecting solar energy and transforming the solar energy into heat energy to heat up the water within the heat collecting tube 21′. Accordingly, each of the heat collecting tube 21′ comprises an outer tubular member, an inner tubular member and a solar energy collecting agent as shown in FIG. 2.
Each of the heat transferring tubes 22′, which is made of heat conductive material, disposed in the respective heat collecting tube 21′ to define a water conduit 210′ between the heat collecting tube 21′ and the heat collecting tube 22′, wherein the heat transferring tube 22′ has a water channel 220′ and an outer opening end 221′ extended towards to the outer closed end 211′ of the heat collecting tube 21′ to communicate the water channel 220′ with the water conduit 210′ of the heat collecting tube 21′ such that the water is guided to flow from the water inlet 11′ to each of the solar heat units 20′ to circularly flow between the water conduit 210′ and the water channel 220′ thereof so as to substantially heat up the water before flowing out at the water outlet 12′ of the water pipe 10′.
As shown in FIG. 3, the solar heat units 20′ are formed in pair wherein each pair of the solar heat units 20′ are opposedly extended from the water pipe 10′ to communicate with the water passage 13′ thereof. Accordingly, the water is guided to flow from the water inlet 11′ to the water outlet 12′ through each pair of the solar heat units 20′ in a zigzag manner.
According to the second embodiment, the two heat transferring tubes 22′ of each pair of the solar heat units 20′ are integrally extended to form an elongated tubular structure through the water pipe 10′ so as to communicate the water channels 220′ with each other such that the water is guided to flow to each pair of the solar heat units 20′ in a zigzag manner that the water flows into the water conduit 210′ of one of the solar heat units 20′ from the water pipe 10′ and then flow into the water channels 220′ to another solar heat unit 20′ so as to return back to the water pipe 10′ through the water conduit 210′ of the respective solar heat unit 20′, as shown in FIG. 3.
The solar energy water heater further comprises a plurality of water guiders 30′ spacedly disposed in the water passage 13′ of the water pipe 10′ to align with the pairs of solar heat units 20′ respectively, wherein each of the water guiders 30′ has a guiding passage 31′ extended to the inner opened end 212′ of the respective heat collecting tube 21′ for guiding the water to flow into the respective water conduit 210′ such that the water flows to the water channel 220′ from the water conduit 210′ through the outer opening end 221′ of the heat transferring tube 22′ and back to the water passage 13′ of the water pipe 10′ from the water conduit 210′. Therefore, the water circularly flows within each of the solar heat units 20′ to substantially heat up the water therewithin by solar energy.
As shown in FIG. 4, a solar energy water heater of a third embodiment illustrates an alternative mode of the second embodiment of the present invention, wherein the solar heat units 20″ are formed in pairs and are transversely and spacedly extended from the water pipe 10″ to communicate with the water passage 13″ thereof. Each of the solar heat units 20″, having the same structure of the first embodiment, comprises a heat collecting tube 21″ and a heat transferring tube 22″.
The water pipe 10″ is operatively communicating with a water source S such that water from the water source S flows into the water pipe 10″ at the water inlet 11″ and flows out at the water outlet 12″. A heat insulating layer 14″ is enclosing an outer surface of the water pipe 10″ for preventing heat loss of the water passing along the water passage 13″.
Each of the heat collecting tubes 21″ has an outer closed end 211″ and an inner opened end 212′ extended from the water pipe 10″, wherein the heat collecting tube 21″ is adapted for collecting solar energy and transforming the solar energy into heat energy to heat up the water within the heat collecting tube 21″. Accordingly, each of the heat collecting tube 21″ comprises an outer tubular member, an inner tubular member and a solar energy collecting agent as shown in FIG. 2.
Each of the heat transferring tubes 22″, which is made of heat conductive material, disposed in the respective heat collecting tube 21″ to define a water conduit 210″ between the heat collecting tube 21″ and the heat collecting tube 22″, wherein the heat transferring tube 22″ has a water channel 220″ and an outer opening end 221″ extended towards to the outer closed end 211″ of the heat collecting tube 21″ to communicate the water channel 220″ with the water conduit 210″ of the heat collecting tube 21″ such that the water is guided to flow from the water inlet 11″ to each of the solar heat units 20″ to circularly flow between the water conduit 210″ and the water channel 220″ thereof so as to substantially heat up the water before flowing out at the water outlet 12″ of the water pipe 10″. It is worth to mention that when the cool water suddenly flows to the heat collecting tube 21″ which is relatively hot, the heat collecting tube 21″ may be cracked due to the sudden change of temperature. Therefore, the water is preheated along the heat transferring tubes 22″ to prevent the crack of the heat collecting tube 21″ when the water flows to the water conduit 210″.
As shown in FIG. 4, the solar heat units 20″ are formed in pair wherein each pair of the solar heat units 20″ are opposedly extended from the water pipe 10″ to communicate with the water passage 13″ thereof. Accordingly, the water is guided to flow from the water inlet 11″ to the water outlet 12″ through each pair of the solar heat units 20″ in a splitting manner that the water is divided evenly to flow to the solar heat units 20″.
The solar energy water heater further comprises a plurality of water guiders 30″ spacedly disposed in the water passage 13″ of the water pipe 10″ to align with the pairs of solar heat units 20″ respectively, wherein each of the water guiders 30″, having a T-shape, has two guiding passages 31″ extended to two inner ends 222″ of the heat transferring tubes 22′ respectively for guiding the water to flow into the water channels 220″ such that the water flows to the water conduits 210″ from the water channels 220″ through the outer opening ends 221″ of the heat transferring tubes 22″ respectively and back to the water passage 13″ from the water conduits 210″, as shown in FIG. 5.
Accordingly, each of the water guiders 30″ has a guiding splitter 32″ disposed within the water passage 13″ for evenly dividing the water therewithin into two portions to flow into the respective pair of solar heat units 20″. In other words, the two portions of the water circularly flow within each pair of solar heat units 20″ to substantially heat up the water therewithin by solar energy.
According to the third embodiment, the water pipe 10″ comprises a plurality of tubular bodies 101″ coaxially mounted with each other to form the water passage 13″ wherein each of the tubular bodies 101″ is positioned between each pair of the solar heat units 20″ such that the solar energy water heater of the present invention is adapted to be easily assembled or disassembled for transportation and storage.
One skilled in the art will understand that the embodiment of the present invention as shown in the drawings and described above is exemplary only and not intended to be limiting.
It will thus be seen that the objects of the present invention have been fully and effectively accomplished. It embodiments have been shown and described for the purposes of illustrating the functional and structural principles of the present invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.

Claims

1. A solar energy water heater, comprising:

a water pipe having a water inlet and a water outlet and defining a water passage therebetween for guiding water to flow from said water inlet to said water outlet; and

a plurality of solar heat units transversely and spacedly extended from said water pipe to communicate with said water passage thereof, wherein each of said solar heat units comprises:

a heat collecting tube having an outer closed end and an inner opened end extended from said water pipe, wherein said heat collecting tube is adapted for collecting solar energy and transforming said solar energy into heat energy to heat up said water within said heat collecting tube; and

a heat transferring tube, which is made of heat conductive material, disposed in said heat collecting tube to define a water conduit between said heat collecting tube and said heat collecting tube, wherein said heat transferring tube has a water channel and an outer opening end extended towards to said outer closed end of said heat collecting tube to communicate said water channel with said water conduit of said heat collecting tube such that said water is guided to flow from said water inlet to each of said solar heat units to circularly flow between said water conduit and said water channel thereof so as to substantially heat up said water at each of said solar heat units before flowing out at said water outlet of said water pipe.

2. The solar energy water heater, as recited in claim 1, further comprising a plurality of water guiders spacedly disposed in said water passage of said water pipe to align with said solar heat units respectively, wherein each of said water guiders has a guiding passage extended to an inner end of said respective heat transferring tube for guiding said water to flow into said respective water channel from said water passage such that said water flows to said respective water conduit from said water channel through said outer opening end of said heat transferring tube and back to said water passage of said water pipe through said inner opened end of said solar collecting tube.

3. The solar energy water heater, as recited in claim 2, wherein said solar heat units are perpendicularly extended from said water pipe at a direction such that said water is guided to flow from said water inlet to each of said solar heat units for heat exchange and to flow out at said water outlet.

4. The solar energy water heater, as recited in claim 1, wherein each of said heat collecting tube comprises an outer tubular member, an inner tubular member sealed therein in end-to-end manner, and a solar energy collecting agent sealedly provided between said outer and inner tubular members, wherein said water conduit is formed between said inner tubular member and said heat transferring tube such that said solar energy collecting agent is adapted for collecting said solar energy to heat up said water within said inner tubular member.

5. The solar energy water heater, as recited in claim 3, wherein each of said heat collecting tube comprises an outer tubular member, an inner tubular member sealed therein in end-to-end manner, and a solar energy collecting agent sealedly provided between said outer and inner tubular members, wherein said water conduit is formed between said inner tubular member and said heat transferring tube such that said solar energy collecting agent is adapted for collecting said solar energy to heat up said water within said inner tubular member.

6. The solar energy water heater, as recited in claim 3, further comprising a heat insulating layer enclosing an outer surface of said water pipe for preventing heat loss of said water passing along said water passage.

7. The solar energy water heater, as recited in claim 5, further comprising a heat insulating layer enclosing an outer surface of said water pipe for preventing heat loss of said water passing along said water passage.

8. The solar energy water heater, as recited in claim 1, wherein said solar heat units are formed in pairs that each pair of said solar heat units are transversely and opposedly extended from said water pipe to communicate with said water passage, wherein said water is guided to flow from said water inlet to said water outlet through each pair of said solar heat units in a zigzag manner.

9. The solar energy water heater, as recited in claim 8, wherein said two heat transferring tubes of each pair of said solar heat units are integrally extended to form an elongated tubular structure through said water pipe so as to communicate said water channels with each other.

10. The solar energy water heater, as recited in claim 8, further comprising a plurality of water guiders spacedly disposed in said water passage of said water pipe to align with said pairs of solar heat units respectively, wherein each of said water guiders has a guiding passage extended to said inner opened end of one of said heat collecting tubes for guiding said water to flow into said respective water conduit of each pair of said solar heat units.

11. The solar energy water heater, as recited in claim 9, further comprising a plurality of water guiders spacedly disposed in said water passage of said water pipe to align with said pairs of solar heat units respectively, wherein each of said water guiders has a guiding passage extended to said inner opened end of one of said heat collecting tubes for guiding said water to flow into said respective water conduit of each pair of said solar heat units.

12. The solar energy water heater, as recited in claim 8, wherein each of said heat collecting tube comprises an outer tubular member, an inner tubular member sealed therein in end-to-end manner, and a solar energy collecting agent sealedly provided between said outer and inner tubular members, wherein said water conduit is formed between said inner tubular member and said heat transferring tube such that said solar energy collecting agent is adapted for collecting said solar energy to heat up said water within said inner tubular member.

13. The solar energy water heater, as recited in claim 11, wherein each of said heat collecting tube comprises an outer tubular member, an inner tubular member sealed therein in end-to-end manner, and a solar energy collecting agent sealedly provided between said outer and inner tubular members, wherein said water conduit is formed between said inner tubular member and said heat transferring tube such that said solar energy collecting agent is adapted for collecting said solar energy to heat up said water within said inner tubular member.

14. The solar energy water heater, as recited in claim 11, further comprising a heat insulating layer enclosing an outer surface of said water pipe for preventing heat loss of said water passing along said water passage.

15. The solar energy water heater, as recited in claim 13, further comprising a heat insulating layer enclosing an outer surface of said water pipe for preventing heat loss of said water passing along said water passage.

16. The solar energy water heater, as recited in claim 1, wherein said solar heat units are formed in pairs that each pair of said solar heat units are transversely and opposedly extended from said water pipe to communicate with said water passage, wherein said water is guided to flow from said water inlet to said water outlet through each pair of said solar heat units in a splitting manner.

17. The solar energy water heater, as recited in claim 16, further comprising a plurality of water guiders spacedly disposed in said water passage of said water pipe to align with said pairs of said solar heat units respectively, wherein each of said water guiders, having a T-shape, has two guiding passages communicatively extended to two inner ends of said heat transferring tubes respectively for guiding said water to flow from said water passage into said water channels.

18. The solar energy water heater, as recited in claim 17, wherein each of said water guiders has a guiding splitter disposed within said water passage for evenly dividing said water therewithin into two portions to flow into said respective pair of said solar heat units.

19. The solar energy water heater, as recited in claim 16, wherein each of said heat collecting tube comprises an outer tubular member, an inner tubular member sealed therein in end-to-end manner, and a solar energy collecting agent sealedly provided between said outer and inner tubular members, wherein said water conduit is formed between said inner tubular member and said heat transferring tube such that said solar energy collecting agent is adapted for collecting said solar energy to heat up said water within said inner tubular member.

20. The solar energy water heater, as recited in claim 18, wherein each of said heat collecting tube comprises an outer tubular member, an inner tubular member sealed therein in end-to-end manner, and a solar energy collecting agent sealedly provided between said outer and inner tubular members, wherein said water conduit is formed between said inner tubular member and said heat transferring tube such that said solar energy collecting agent is adapted for collecting said solar energy to heat up said water within said inner tubular member.

21. The solar energy water heater, as recited in claim 18, further comprising a heat insulating layer enclosing an outer surface of said water pipe for preventing heat loss of said water passing along said water passage.

22. The solar energy water heater, as recited in claim 20, further comprising a heat insulating layer enclosing an outer surface of said water pipe for preventing heat loss of said water passing along said water passage.

23. A method of heating water through a solar energy water heater which comprises a water pipe and a plurality of solar heat units transversely and spacedly extended therefrom, each said solar heat units comprising a heat collecting tube and a heat transferring tube which is made of heat conductive material disposed therein, wherein said method comprises the steps of:

(a) guiding said water to flow into a water inlet of said water pipe to each of said solar heat units;

(b) guiding said water to flow into a water channel of said heat transferring tube from an inner end of said heat transferring tube towards an outer opening end thereof so as to heat up said water along said water channel, wherein said inner end of said heat transferring tube is extended from said water pipe to communicate said water channel with said water pipe;

(c) guiding said water to flow into a water conduit from said outer opening end of said heat transferring tube to heat up said water along said water conduit, wherein said water conduit is formed between said heat collecting tube and said heat collecting tube, wherein said outer opening end of said heat transferring tube is extended towards to an outer closed end of said heat collecting tube to communicate said water channel with said water conduit of said heat collecting tube;

(d) guiding said water to flow into said water pipe from an inner opened end of said heat collecting tube, wherein said inner opened end of said heat collecting tube is extended from said water pipe to communicate said water conduit with said water pipe; and

(e) guiding said water to flow out of said water pipe at a water outlet thereof.

24. The method, as recited in claim 23, wherein said solar heat units are formed in pairs that each pair of said solar heat units are transversely and opposedly extended from said water pipe to communicate with said water passage, wherein, in step (b), said water is split into two portions to respectively flow into said water channels of said heat transferring tubes of said pair of said solar heat units.

25. The method, as recited in claim 23, wherein each of said heat collecting tube comprises an outer tubular member, an inner tubular member sealed therein in end-to-end manner, and a solar energy collecting agent sealedly provided between said outer and inner tubular members, wherein said water conduit is formed between said inner tubular member and said heat transferring tube such that said solar energy collecting agent is adapted for collecting said solar energy to heat up said water within said inner tubular member.

26. The method, as recited in claim 24, wherein each of said heat collecting tube comprises an outer tubular member, an inner tubular member sealed therein in end-to-end manner, and a solar energy collecting agent sealedly provided between said outer and inner tubular members, wherein said water conduit is formed between said inner tubular member and said heat transferring tube such that said solar energy collecting agent is adapted for collecting said solar energy to heat up said water within said inner tubular member.