Protection system for a solar water heating system

• US 20060107944A1
• Filed: 09/20/2005
• Published: 05/25/2006
• Est. Priority Date: 04/11/2003
• Status: Active Grant

• Current Assignee: Brendan Vincent Bourke
• Original Assignee: Rheem Australia Pty Limited (Paloma Co., Ltd.)
• Inventors: Bourke, Brendan Vincent
• Granted Patent: US 8,220,453 B2
• Time in Patent Office: Days
• US Class Current: 126/599
• CPC Class Codes: F24D 17/0021 with accumulation of the heated water
• CPC Class Codes: F24S 10/95 having evaporator sections and condenser sections, e.g. heat pipes
• CPC Class Codes: F24S 40/53 by venting solar heat collector enclosures
• CPC Class Codes: F24S 40/58 Preventing overpressure in working fluid circuits
• CPC Class Codes: F24S 60/30 storing heat in liquids
• CPC Class Codes: Y02B 10/20 Solar thermal
• CPC Class Codes: Y02B 10/70 Hybrid systems, e.g. uninterruptible or back-up power supplies integrating renewable energies
• CPC Class Codes: Y02E 10/40 Solar thermal energy, e.g. solar towers
• CPC Class Codes: Y02E 10/44 Heat exchange systems

Abstract

The present invention includes a solar water heating system including: a water tank to hold water to be heated, an heat transfer fluid circuit including an heat exchanger associated with said water tank to heat water therein, a solar collection means in communication with said heat exchanger, an inlet connection to carry heat transfer fluid from said solar collection means to said heat exchanger where said water will be heated; and an outlet connection to carry heat transfer fluid from said heat exchanger to said solar collection means where said heat transfer fluid will be heated, said heat transfer fluid circuit including a reversibly evaporable heat transfer fluid which will absorb heat from said solar collection means and which will transfer said heat to said water in said water tank by means of said heat exchanger; and an diversion path being provided in said heat transfer circuit, whereby when a portion of heat transfer fluid changes to a gaseous state in said solar collection means, heat transfer fluid in a liquid state will be forced out of said solar collection means under pressure into said diversion path.

Claims

1. A solar water heating system including:

a water tank to hold water to be heated,

a heat transfer fluid circuit including an heat exchanger associated with said water tank to heat water therein,

a solar collection means in communication with said heat exchanger,

an inlet connection to carry heat transfer fluid from said solar collection means to said heat exchanger where said water will be heated; and

an outlet connection to carry heat transfer fluid from said heat exchanger to said solar collection means where said heat transfer fluid will be heated,

said heat transfer fluid circuit including a reversibly evaporable heat transfer fluid which will absorb heat from said solar collection means and which will transfer said heat to said water in said water tank by means of said heat exchanger; and

a liquid diversion path including a receptacle arranged to receive liquid phase HTF from the heat transfer fluid circuit when heat transfer fluid in the solar panel vaporizes;

whereby when a portion of heat transfer fluid changes to a gaseous state in said solar collection means, heat transfer fluid in a liquid state will be forced out of said solar collection means under pressure into said diversion path.

2. A solar water heating system as claimed in claim 1, wherein the diversion path is a pressure controlled diversion circuit.

3. A solar water heating system as claimed in claim 1, wherein the receptacle is one of a vessel, an expansion vessel, or a reservoir.

4. A solar water heating system as claimed in claim 1, wherein the diversion path includes a pressure controlled valve adapted to admit heat transfer fluid to the receptacle when the pressure in the heat transfer fluid circuit exceeds a first pressure threshold.

5. A solar water heating system as claimed in claim 1, wherein the diversion path is adapted to deliver heat transfer fluid to the heat transfer circuit when the pressure in the heat transfer fluid circuit falls below the pressure in the diversion path.

6. A solar water heating system as claimed in claim 1, wherein said inlet connection exits said solar collection means at a first location which is above a second location where said outlet connection enters said solar collection means, said system being characterised by including a flow stop means to stop the flow of said heat transfer fluid in response to a signal indicative of the heat transfer fluid circuit having attained a predetermined over-temperature condition.

7. A solar water heating system as claimed in claim 6, wherein said inlet connection includes a valve means which can be closed.

8. A solar water heating system as claimed in claim 6, wherein said outlet connection includes a valve means which can be closed.

9. A solar water heating system as claimed in claim 1, wherein said heat transfer fluid in a liquid state is forced out of said solar collection means under pressure passes via said second location and then into said diversion path.

10. A solar water heating system as claimed in claim 1, wherein said inlet connection exits said solar collection means at a first location and said outlet connection entering said solar collection means at a second location, said first location and second location both being located at the lower end of the solar collection means, whereby said heat transfer fluid in a liquid state will be forced out of said solar collection means under pressure via said second location and or said first location and into said diversion path.

11. A solar water heating system as claimed in claim 1, wherein direction of flow of said heat transfer fluid leaving said solar collection means to enter said diversion path is in the opposite direction as for the normal heating operation of said system.

12. A solar water heating system as claimed in claim 1, wherein direction of flow of said heat transfer fluid leaving said solar collection means to enter said diversion path is in the same direction as for the normal heating operation of said system.

13. A solar heating system as claimed in claim 1, wherein a valve means is used to prevent gaseous heat transfer fluid being pushed out of said solar collectors.

14. A solar water heating system as claimed in claim 1, wherein said heat exchanger is a jacket located around said water tank.

15. A solar water heating system as claimed in claim 1, wherein said heat exchanger is located inside of said water tank.

16. A solar water heating system as claimed in claim 1, wherein said diversion path is provided separate of said heat exchanger.

17. A solar water heating system as claimed in claim 1, wherein said water tank includes said diversion path, or said diversion path is attached thereto or included therein.

18. A solar water heating system as claimed in claim 1, wherein the heat exchanger associated with said water tank to heat water therein, is a brazed plate heat exchanger.

19. A solar water heating system as claimed in claim 1, wherein said solar collection means or said outlet connection includes, between said diversion path and said solar collection means, a liquid trap, to prevent gas passing therethrough.

20. A solar water heating system as claimed in claim 1, wherein the volume able to be received by said diversion path is in the range of the volume of heat transfer fluid in said solar collection means up to the total volume of heat transfer fluid in the system.

21. A solar water heating system as claimed in claim 1, wherein volume able to be received by said diversion path is in the range of the volume of heat transfer fluid in said solar collection means plus said inlet and said outlet connections up to the total volume of heat transfer fluid in said system.

22. A solar water heating system as claimed in claim 1, wherein said solar collection means has collection flow tubes oriented in a substantially horizontal orientation.

23. A solar water heating system as claimed in claim 1, wherein said solar collection means has collection flow tubes oriented in a substantially vertical orientation.

24. A solar water heating system as claimed in claim 1, wherein said solar collection means has collection flow tubes oriented at an angle to the vertical or horizontal.

25. A solar water heating system as claimed in claim 1, wherein said heat transfer fluid circuit has the heat transfer fluid circulate therein by means of thermosyphoning.

26. A solar water heating system as claimed in claim 1, wherein said heat transfer fluid circuit has the heat transfer fluid circulate therein by a pump means.

27. A solar water heating system as claimed in claim 26, wherein said pump is switched off when an over temperature or over pressure condition is detected in said system.

28. A solar water heating system as claimed in claim 26, wherein said pump is located in said outlet connection between an outlet of said heat exchanger and the inlet to said solar collection means.

29. A solar water heating system as claimed in claim 1, wherein a valve is included in said heat transfer circuit so that thermosyphoning in cool ambient conditions will not occur.

30. A solar water heating system as claimed in claim 1, wherein said heat transfer circuit also has a one way valve in said circuit.

31. A solar water heating system as claimed in claim 26, wherein a valve to prevent said heat transfer fluid flowing in a direction opposite to said pumping direction is located in said inlet connection between an outlet of said solar collection means and the inlet to said heat exchanger.

32. A solar water heating system as claimed in claim 1, wherein said solar collection means is a flat plate collector.

33. A solar water heating system as claimed in claim 1, wherein said solar collection means includes two or more solar collection panels being connected in series with said inlet connection and said outlet connection.

34. A solar water heating system as claimed in claim 1, wherein said solar collection means includes two or more solar collection panels being connected in parallel with said inlet connection and said outlet connection.

35. A solar water heating system as claimed in claim 33, wherein heat transfer fluid ascends in a first panel and transfers to a second panel wherein it descends to exit said second panel.

36. A solar water heating system as claimed in claim 33, wherein heat transfer fluid ascends in a first half of each panel and transfers to a second half wherein it descends to exit the panel.

37. A solar water heating system as claimed in claim 1, wherein said heat transfer fluid includes a 1,2-propylene glycol, water and inhibitors.

38. A solar water heating system as claimed in claim 1, wherein said heat transfer fluid is that known by the brand name TYOFOCOR LS manufactured by Tyforop Chemie GmbH, or its equivalent.

39. A solar water heating means as claimed in claim 29, wherein said valve means is a non return valve and or a remotely controlled isolating valve.

40. A solar water heating system as claimed in claim 6, wherein said flow stop means and a valve included in said heat transfer circuit so that thermosyphoning in cool ambient conditions will not occur, are combined in a single isolation valve.

41. A solar water heating system as claimed in claim 1, wherein said flow stop means will switch off a pump circulating said heat transfer fluid in said circuit.

42. A solar heating system as claimed in claim 1, wherein said diversion path is branched off said outlet connection.

43. A solar heating system as claimed in claim 1, wherein said diversion path is branched off said inlet connection.

44. A solar water heating system as claimed in claim 42, wherein said diversion path is located between said pump and said inlet to said solar collection means.

45. A solar water heating system as claimed in claim 4, wherein said pressure controlled valve is forced to operate by said heat transfer fluid acting indirectly thereon, such as by means of air being pressurised by said heat transfer fluid.

46. A solar water heating system as claimed in claim 45, wherein said diversion path communicates with the heat transfer fluid circuit, whereby once pressure in said circuit reduces, any liquid heat transfer fluid which passed into said receptacle can pass back into said heat transfer fluid circuit.

47. A solar water heating system as claimed in claim 1, wherein a pressure controlled valve is present between said heat transfer fluid circuit and said diversion path, whereby heat transfer fluid passing to said diversion path does so via said pressure controlled valve into said diversion path.

48. A solar water heating system as claimed in claim 1, wherein said diversion path is vented to atmosphere.

49. A solar water heating system as claimed in claim 46, wherein heat transfer fluid passing said pressure controlled valve exits a conduit from said pressure controlled valve which terminates near to the bottom of said receptacle.

50. A solar water heating system as claimed in claim 46, wherein said receptacle includes an amount of liquid heat transfer fluid in the bottom thereof to a level which will cover the termination of said conduit.

51. A solar water heating system as claimed in claim 46, wherein said pressure controlled valve is of the type which has a one way valve to allow fluid passing into said diversion path to re-enter said circuit.

52. A solar water heating system as claimed in claim 1, wherein said heat transfer fluid circulates in said circuit by means of a pump, while said water is heated by a thermosyphoning mechanism.

53. A method of protecting a solar water heating system, said method including the steps of:

allowing some of the heat transfer fluid in said system to boil in solar collectors in said system, whereby once boiled the heat transfer fluid in the gaseous state will force liquid heat transfer fluid from said collectors, and accommodating the expanded volume of heat transfer fluid in a diversion path.

54. A method as claimed in claim 53, wherein a valve means is used to prevent gaseous heat transfer fluid moving out of said solar collectors via the outlet of said solar collectors, said outlet being that opening from which heated heat transfer fluid would normally exit said collectors to travel to a heat exchanger to heat water in a tank of said system.

55. A method as claimed in claim 53, wherein said diversion path is located between an outlet of the heat exchanger of said system and the inlet to the solar collectors, said inlet being that opening from which cooled heat transfer fluid would normally enter said collectors after heating water in a tank via a heat exchanger.

56. A method as claimed in claim 54, wherein said diversion path is located between an outlet of the heat exchanger of said system and the inlet to the solar collectors, said inlet being that opening from which cooled heat transfer fluid would normally enter said collectors after heating water in a tank via a heat exchanger.