Solar energy system

Abstract

A system comprising a structure (1) defining a volume for containing or receiving a body of water. The system further comprises a solar energy system for heating a body of water. The system comprises a solar radiation receiving unit (2) configured to receive solar radiation and configured to convert said solar radiation into heat energy. The system also comprises a barrier means (3) of varying solar radiation transmittance arranged over said solar radiation receiving unit (2). The barrier means (3) is configured to varyingly control the solar radiation receivable by said solar radiation receiving unit (2).

Claims

1. A solar energy system for heating a body of water, the system comprising: a solar radiation receiving unit that receives solar radiation and converts said solar radiation into heat energy; a barrier that varies solar radiation transmittance arranged over said solar radiation receiving unit, wherein the barrier varyingly controls the solar radiation receivable by said solar radiation receiving unit, the barrier comprising an electrochromic material; a controller that automatically controls the solar radiation transmittance of the barrier based on a temperature; a sensor for measuring said temperature; a first pump that pumps a fluid through said solar radiation receiving unit and a first fluid circuit through which fluid can be pumped through said radiation receiving unit; an energy storage device comprising a tank, wherein the first pump pumps fluid from the solar radiation receiving unit to the tank; and a heat exchanger for transferring heat from the solar radiation receiving unit to the energy storage device, wherein the heat exchanger is fluidly connected to the first fluid circuit.

2. A solar energy system for heating a body of water, the system comprising: a solar radiation receiving unit that receives solar radiation and converts said solar radiation into heat energy; a barrier that varies solar radiation transmittance arranged over said solar radiation receiving unit, wherein the barrier varyingly controls the solar radiation receivable by said solar radiation receiving unit, the barrier comprising an electrochromic material; a controller that automatically controls the solar radiation transmittance of the barrier based on a temperature; a sensor for measuring said temperature; a first pump that pumps a fluid through said solar radiation receiving unit and a first fluid circuit through which fluid can be pumped through said radiation receiving unit; an energy storage device comprising a tank, wherein the first pump pumps fluid from the solar radiation receiving unit to the tank; a secondary fluid circuit fluidly connected to said energy storage device, wherein the secondary fluid circuit is fluidly isolated from the first fluid circuit; and a second pump that pumps fluid around the secondary fluid circuit.

3. The system of claim 2, wherein the second pump is activated when the temperature in the secondary fluid circuit or energy storage device falls below a predetermined temperature.

4. The system as claimed in claim 2, wherein the second pump comprises a twin pump.

5. The system of claim 2 further comprising: a further heat source that supplies energy to the energy storage device.

6. A method of heating a body of water, the method comprising: providing a solar radiation receiving unit configured to receive solar radiation and convert said solar radiation into heat energy; providing a barrier for varying solar radiation transmittance arranged over said solar radiation receiving unit, wherein the barrier is configured to varyingly control the solar radiation receivable by said solar radiation receiving unit, and the barrier comprises an electrochromic material; providing a controller that is configured to automatically control the solar radiation transmittance of the barrier based on a temperature; providing a sensor for measuring said temperature; configuring the barrier in a first state in which it substantially permits the transmission of solar radiation; configuring the barrier in a second state in which it substantially prevents the transmission of solar radiation once a predetermined temperature has been reached in the body of water; wherein the solar radiation receiving unit and barrier means are provided, in use, submerged in a body of water contained in a structure such that the heat energy from the solar radiation receiving unit is transferred to the water contained in the structure; pumping, using a first pump, a fluid through said solar radiation receiving unit; isolating fluidly, a first fluid circuit from the body of water in said volume, through which fluid can be pumped through said radiation receiving unit; activating the first pump for pumping fluid through the solar receiving unit when a predetermined temperature has been reached or exceeded in the body of water; providing an energy storage device comprising a tank; configuring the first pump to pump fluid from the solar radiation receiving unit to the water tank; providing a secondary fluid circuit fluidly connected to said energy storage device, wherein the secondary fluid circuit is fluidly isolated from the first fluid circuit; providing a second pump for pumping fluid around the secondary fluid circuit; and configuring the barrier in a said first state when the temperature of fluid in the secondary circuit or tank falls below a predetermined temperature.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) The present invention may be carried out in various ways and embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which:

(2) FIG. 1 is a perspective cutaway view of a swimming pool with electrochromic glass arranged over a solar water heater;

(3) FIG. 2 is a schematic of the solar water heater connected by a series of pipes to a heat exchanger in a water tank;

(4) FIG. 3 is a schematic of electrochromic glass arranged over a solar water heater, and of a water tank and a secondary circuit;

(5) FIG. 4 is a schematic of a secondary circuit pumping means with an arrangement of valves;

(6) FIG. 5 is a schematic of a secondary circuit pumping means with an alternative arrangement of valves;

(7) FIG. 8 is a schematic of barrier means of varying solar radiation transmittance in a first state substantially reflecting solar radiation and in a second state substantially transmitting solar radiation;

(8) FIG. 7 is a section view of a swimming pool with electrochromic glass and a solar water heater recessed in the floor of the swimming pool;

(9) FIG. 8 is a section perspective view of a swimming pool with electrochromic glass and solar water heater recessed in the floor of the swimming pool with a support structure and showing the inlet and outlet to the solar water heater;

(10) FIG. 9 is a perspective cutaway view of the swimming pool with apertures within the electrochromic glass;

(11) FIG. 10 is a perspective cutaway view of the swimming pool with electrochromic glass as shown in FIG. 8 with the solar water heater recessed in the floor of the swimming pool and showing the support structure and electrical power cable and to control the electrochromic glass;

(12) FIG. 11 is a perspective view of a bracket which enables the electrochromic glass to be removed from the swimming pool;

(13) FIG. 12 is a perspective cutaway view of the swimming pool with wireless transmitter and receiver; and

(14) FIG. 13 is a perspective cutaway view of the swimming pool comprising substantially reflective walls.

DETAILED DESCRIPTION

(15) An example of a solar energy system for heating a body of water is shown in FIG. 1. The system comprises a solar radiation receiving unit 2, in the embodiment in the form of a solar water heater and a barrier means of varying solar radiation transmittance 3 arranged over said solar radiation receiving unit 2. The system can be used to heat a body of water within a swimming pool 1.

(16) The swimming pool structure 59 is recessed into the surrounding ground. A poolside surface 60 forms a margin around the perimeter of the swimming pool 1. For illustrative purposes, the swimming pool 1 is shown without the swimming pool water. The structure of the swimming pool 59 comprises four vertical walls; two opposing longitudinal, vertical and generally planar walls 37, 38, one of which 38 is not shown for clarity, and two opposing lateral, vertical and generally planar walls 39, 40. A base wall 34 forms the floor of the pool. One of the lateral walls 39 extends vertically downwards more so than the other lateral wall 40 so that one end of the swimming pool 1 is deeper than at the other end.

(17) The deepest end of the swimming pool 1 comprises a flat planar floor 42 which extends horizontally from the base of the lateral, vertical wall 39 at the deepest end. The flat planar floor 42 extends to approximately a quarter of the length of the swimming pool 1. The remaining length 41 of the swimming pool's floor 1 is curved. The curved floor 41 curves upwards in a substantially convex form from the flat planar floor 42 to meet the bottom of the lateral vertical wall 40 at the shallowest end.

(18) In this example the solar radiation receiving unit comprises four rectangular and substantially planar solar-radiation receiving panels 2. The panels are recessed into the curved section of the swimming pool floor 41 and lie such that they are inclined to the horizontal. The angle of inclination is chosen such that the intensity of solar radiation received by the panels is optimised, for example depending on the peak intensity of the sun in the part of the world where the system is installed. The panels are formed with a substantially black surface or layer in order to absorb energy from the solar-radiation incident on the panels. A glass panel may be provided in front of the black surface. The panels are aligned in a row which extends substantially across the width of the swimming pool 1, perpendicular to the vertical swimming pool walls 37, 38 at either end of the row.

(19) The panels each comprise a network of tubes 43 which pass within each panel. The network of tubes is configured to allow fluid to pass through the network. This fluid could be antifreeze, water, a mixture of both or any other suitable fluid for carrying heat and remaining in liquid state at all temperatures and pressures which the fluid may reasonably be expected to encounter within the tubes. The network of tubes comprises two lateral tubes 53, 54 which run parallel to the width of each panel. The two lateral tubes 53, 54 are spaced apart from each other such that they are located at opposing ends of the panel. The two lateral tubes 53, 54 extend through the entire width of the panel, thus forming two apertures on one of the longitudinal side faces of the panel and two on the other longitudinal side face. The two apertures on each of the side faces form a fluid inlet 35 and a fluid outlet 36 to the network of tubes 43 within each panel. A plurality of transverse, linear tubes 55 run from one lateral tube 53 to the other lateral tube 54, thus forming a parallel circuit. The transverse tubes 55 are spaced at equal intervals along the length of the lateral tubes 53, 54. Fluid may thus pass from one lateral tube 53, through the plurality of longitudinal tubes 55, to the other lateral tube 54. The inlet 35 and outlet 36 apertures of the row of panels 2 are interconnected such that fluid may pass from one panel to the next panel in the row. The distal panel 61 comprises inlet and outlet apertures in only one of its longitudinal side faces such that the fluid that flows through the most distal panel enters the panel by only one inlet and exits by only one outlet.

(20) Barrier means of varying solar radiation transmittance, in the embodiment in the form of electrochromic glass panes 3, sit above the panels 2 such that a space 25 is formed between the glass panes 3 and the solar radiation receiving units or panels 2.

(21) Electrochromic glass is more commonly known to those skilled in the art as ‘smart glass’. Electrochromic glass is configured to change its light transmittance properties when a voltage is applied. The glass panes 3 are aligned in a row of substantially the same area as, and coextensive with, the row of panels 2. The row of glass panes 3 extends substantially across the width of the swimming pool 1, perpendicular to the vertical swimming pool walls 37, 38 at either end of the row of glass panes 3. The glass panes 3 are of substantially the same curvature as that of the curved section 41 of the swimming pool floor 34. The glass panes are spaced above the panels 2 such that their upper surface aligns with the surrounding swimming pool floor 41. The row of glass panes 3 are sized such that a gap between the glass panes 3 and the surrounding swimming pool floor 41 is provided around the perimeter of the row of glass panels by which water may enter the space 25 between the glass panes 3 and the panels 2. Support members 28 are fixed substantially perpendicular to the active surface of the panels. The support members are spaced at regular intervals along the centreline of the row of panels 2. The support members 28 are square in cross section and extend from the upper surface of the panels 2 to the lower surface of the glass panes 3.

(22) The barrier means in the form of glass panes 3 is transparent in a first state so that light is able to pass through the glass panes. Upon passing through the glass panes 3, the light irradiates the panels 2 which lie below the glass panes 3. The panels 2 absorb energy from the incident light and convert the energy of the light into thermal energy. The thermal energy is then absorbed by both the water within the space 25 above the panels 2 and by the liquid within the tubes which pass through the panels 2. The heated water within the space 25 passes through the perimeter gap between the glass panes 3 and the surrounding swimming pool floor 41, and mixes with the main body of water within the swimming pool 1. The temperature of the swimming pool water can thus be increased. The pool may be provided with a conventional filtering unit which comprises a pump. The pumping of the water in the pool by such a pump can serve to facilitate the flow of water passed over the solar radiation receiving unit.

(23) In a second state, the glass panes 3 are opaque and so reduce the quantity of light incident on the solar-radiation receiving panels 2. The light that would have otherwise reached the panels 2 is either substantially reflected or absorbed by the glass panes 3. As a consequence of less light striking the panels 2, less light is absorbed by the panels 2, less light energy is converted into thermal energy and so less thermal energy is produced by the panels 2. As a result, the panels 2 do not transfer as much heat to the water within the space 25 above the panels 2 and to the liquid within the tubes 43 which pass through the panels 2. The temperature increase of the swimming pool water and of the liquid within the panels 2 is therefore substantially prevented compared to that in the first state.

(24) In an initial state, the swimming pool water is cooler than a desired temperature. The user initiates the control process and sets a desired temperature.

(25) As the temperature of the water is below the desired temperature, the control process sets the electrochromic glass panes 3 to a substantially transparent state. Light now passes through the glass panes 3 and is absorbed by the panels 2 below. The panels 2 consequently increase in temperature and transfer some of their heat energy to the water within the space 25 and to the stationary water within the panels 2. The temperature of the swimming pool water consequently increases in the manner described above.

(26) When the swimming pool water eventually reaches the desired temperature an in-line pump is activated which circulates water within the panels to a heat exchanger in an energy storage means such as a water tank as described in further detail in relation to FIG. 2. This circulation causes heat to be continually supplied to the water within the water tank. When the water within the water tank reaches a predetermined temperature, neither the water within the swimming pool or within the water tank require further heating and so the electrochromic glass panes 3 are set to a substantially opaque state in which light is no longer permitted to irradiate the panels 2 below and the in-line pump deactivated. Consequently, no further heating of the water within either the swimming pool or water tank occurs.

(27) A schematic of an example of a solar energy system for providing heated water 4 to a shower 12 or other domestic appliance is shown in FIG. 2. A single substantially planar solar-radiation receiving panel 2 is submerged within a body of water 5. The panel 2 is substantially inclined to the horizontal. In this example, the panel 2 comprises only one fluid inlet 35 and only one fluid outlet 36. The fluid outlet 36 is located on a lateral side face 63 of the panel. The fluid inlet 35 is located on a longitudinal side face 64 of the panel. For clarity, the network of tubes within the panel is not shown. Also not shown for clarity is the electrochromic glass. A first length of pipework 65 connects the panel's fluid outlet 36 aperture to a heat exchanger 7. The heat exchanger 7 is in the form of a coil of tubing, preferably composing a material of high thermal conductivity such as a metal. A second length of pipework 66 connects the heat exchanger 7 to the panel's inlet aperture 35. A pump 6 is connected in-line with the second length of pipework 66. The pump 6 circulates the fluid within the panel 2 around the circuit formed by the first length of pipework 65, the heat exchanger 7, the second length of pipework 66 and the network of tubes 43 within the panel 2.

(28) The heat exchanger 7 is located within a water tank 8. The water tank 8 contains a body of water 67. In operation, the temperature of the fluid that passes within the heat exchanger's 7 tubing is greater than the temperature of the water 67 within the wafer tank 8. The heat from the fluid within the heat exchanger 7 is thus conducted through the tubing to the water 67 within the water tank 8.

(29) The water tank 8 comprises an additional heat exchanger 15 by which an alternative source of heat may be supplied to the water tank 8, e.g. from a gas boiler 14. The additional heat exchanger 15 is in the form of a coil of tubing. A gas boiler 14 is provided which heats a fluid which is then passed by a pump means (not shown) through the additional heat exchanger 15. The fluid within the additional heat exchanger 15 is hotter than the water 67 within the water tank 8 such that heat is conducted through the additional heat exchanger's 15 coiled tubing to the water 67 within the water tank 8. The gas boiler can be used to supplement the heat produced by the solar radiation receiving means.

(30) The pump means may be operated according to the temperature of fluid in the water tank or in a secondary fluid circuit 11.

(31) The wafer tank 8 further comprises a water inlet 13, preferably located towards the bottom of the water tank 8. Cool water is supplied to the water tank 8 through the water inlet 13 in order to replenish the water 67 within the water tank 8. The cool water is preferably from the mains supply. The water tank 8 also comprises a water outlet 68 which is spaced from the water inlet 13 and is preferably located towards the top of the wafer tank 8.

(32) The water outlet 68 is connected to an outlet pipe 9. Heated water is extracted from the water tank 8 through the outlet pipe 9. A blending valve 10 is connected in-line with the outlet pipe 9. The blending valve 10 is connected to an external supply of cool water 69. The blending valve 10 adds cool water to the heated water within the outlet pipe 9 in order to reduce the temperature of the water downstream of the blending valve 10. Once cooled, the heated water is passed along the outlet pipe 9 to a shower 12 or other appliance for which hot water is required.

(33) In an alternative embodiment (not shown), the solar radiation receiving unit may be formed as a photovoltaic cell. The cell can be used similarly as the solar radiation receiving unit of FIG. 1 to heat the pool by convection, but may also produce current which can be transferred to a storage means such as a battery.

(34) FIG. 3 is a schematic showing a further example of a solar energy system similar to that shown in FIG. 2. This particular configuration allows multiple appliances to be supplied with hot water by providing a secondary circuit 11. The solar energy system of FIG. 3 comprises a row of electrochromic glass panes 3 arranged over a row of solar-radiation receiving panels 2 with a first 65 and second 66 length of pipework connecting the heat exchanger to the inlet 35 and outlet 36 apertures respectively of the row of panels 2. This arrangement of electrochromic glass panes and solar-radiation receiving panels functions similarly to the system described in relation to FIG. 1. The first 65 and second 66 lengths of pipework are connected to a tank 8. A pump 6 is connected in line with the first length of pipework 65 and circulates fluid around the circuit of the first and second lengths of pipework. The secondary circuit 11 is connected to an outlet 68 of the water tank 8. The secondary circuit is connected to the water tank via an inlet 13 to form a loop along which multiple appliances may be added.

(35) The water is pumped around the secondary circuit 11 by a twin pump arrangement 17, located between the last appliance on the secondary circuit 11 and the water tank inlet 13. The twin pump arrangement 17 comprises two pumps 20, 22. One of the two pumps 20 is controlled by a gas boiler's thermostatic controller in the case where a gas boiler provides supplementary heat to the tank 8 similarly to the embodiment of FIG. 2. The other pump 22 is controlled by a wire 19 leading to a wire centre or control unit 18. The control unit or wire centre 18 may be provided as a programmable control unit or other unit by which a user can control the system. The wire centre may be controlled by an E-bus, radio frequency (RF) signal or mobile phone or other wireless connection. The twin pump arrangement 17 enables the flow of water around the secondary circuit 11 to be controlled by either the wire centre 18 or the gas boiler thermostatic controller, or a combination thereof. The twin pump arrangement 17 circulates the water around the secondary circuit 11.

(36) The system can be configured such that the barrier means 3 is controlled to permit solar radiation to irradiate the solar radiation receiving unit 2 when the temperature of water in the secondary circuit 11 falls below a set temperature, for example 45 degrees centigrade.

(37) This agitation of the water, in combination with its temperature being maintained in the manner described above, seeks to inhibit the growth of Legionella bacteria within the water of the secondary circuit 11.

(38) A blending valve 10 is connected on the secondary circuit 11 between the water tank outlet 9 and the first appliance on the secondary circuit 11. The blending valve 10 may be used to add cool water from an external water supply 12 to the heated water within the secondary circuit 11. An additional external water supply 56 is also connected to the secondary circuit 11 downstream of the twin pump arrangement 17 in order to ensure that the water level in the tank 8 is maintained at a predetermined level. The flow of water into the secondary circuit 11 from this external water supply 56 is controlled by a check valve 16 which is connected in-line with the external water supply 56.

(39) Two examples of a twin pump arrangement 17 are shown in FIG. 4 and FIG. 5. Either of these two examples of twin pump arrangement 17 can be used in the solar energy system of FIG. 3. In both FIG. 4 and FIG. 5, the two pumps 20, 22 are connected in a parallel circuit 47 comprising two branches 45, 46 such that one pump is located on each branch. One of the pumps 20 is operated by a wire centre or control unit 18 via an electrical cable 19 running from the wire centre 18 to the pump 20. The other pump 22 is controlled by a conventional gas boiler thermostatic controller, the control signal being carried by an electrical wire 21 connected to the pump 22. In FIG. 4, a valve 23 is located upstream of the parallel circuit 47. Another valve 24 is located downstream of the parallel circuit 47.

(40) FIG. 5 shows an alternative arrangement with two valves 49, 50 and 51, 52 being located on each branch 45, 46 of the two branches of the parallel circuit 47, one valve 50, 52 being located upstream of the pump 20, 22 and the other valve 49, 51 being located downstream of the pump 20, 22. The twin pump arrangement 17 shown in FIG. 4 is advantageous in that fewer valves are required in this arrangement compared to that shown in FIG. 5. The pumps 20, 22 within the twin pump arrangement 17 of FIG. 4 are consequently easier and quicker to remove and reinstall should both pumps 20, 22 be required to be replaced. The arrangement shown in FIG. 5 is advantageous in that it allows one of the pumps to continue to operate if the other becomes defective or while the other is being replaced.

(41) FIG. 6a and FIG. 6b are schematics of the swimming pool comprising a solar energy system shown in FIG. 1 in which the interaction of solar radiation with the electrochromic glass 3 in a first state 57, FIG. 6a, and second state 58, FIG. 6b, is depicted. The swimming pool comprises a row of solar radiation receiving panels 2 recessed in a curved section of the swimming pool floor 41. The panels 3 are inclined to more directly face the incident solar radiation. This can be designed according to the peak solar radiation which may be incident on the panels 3. A row of electrochromic glass, in the embodiment curved panes 2, are spaced over the solar-radiation receiving panels 2 at a height such that the glass panes 3 lie flush with the surrounding swimming pool floor 41.

(42) In a first state, the electrochromic glass panes 3 are substantially opaque. Sunlight 24 travels through the swimming pool water until it strikes the surface of the glass panes 3. Being opaque and substantially reflective, the glass panes 3 prevent the incident sunlight 24 from reaching the panels 2 by reflecting the incident sunlight 24 away from the panels 2 and back through the swimming pool water.

(43) In a second state, the electrochromic glass panes 3 are substantially transparent. Sunlight 24 travels through the swimming pool water. Upon reaching the electrochromic glass panes 3, the sunlight 24 is permitted to pass through them and continues to travel towards the panels 2 below. The sunlight 24 strikes the panels 2 and is absorbed by them, with little to no sunlight 24 being reflected by the panels 2. The absorption of sunlight 24 causes the panels 2 to increase in temperature. This thermal energy is then transferred to the swimming pool water within the space 25 between the glass panes 3 and the panels 2, and also to the fluid within the row of panels 2.

(44) FIG. 7 is a cross section view of the swimming pool comprising a solar energy system of FIG. 1 in which the convection currents 27 within the swimming pool water are shown. In this diagram, the swimming pool is shown containing water. A row of substantially rectangular solar-radiation receiving panels 2 is located within a recess in a curved floor 41 of the swimming pool. For clarity, the network of tubes passing within the solar radiation receiving panels and a support structure are not shown.

(45) A row of curved electrochromic glass panes 3 is positioned spaced from the row of panels 2 and aligned with the swimming pool floor 41 on either side of the row of glass panes 3. The row of glass panes 3 and the row of panels 2 are spaced such that a water-filled space 25 exists between them.

(46) Heated water within the space 25 flows through apertures 26 in the glass panes 3 and intermixes through convection currents with the cooler main body of swimming pool water 5 above the glass panes 3. Due to the decrease in pressure within the space 25 as a result of heated water having escaped from the space 25, or due to differences in the density between water at different temperatures in the body of water, cooler water is drawn into the space 25 from the main swimming pool water 5, through the apertures 26 in the glass panes 3. The swimming pool also comprises a conventional filtration and pump system which agitates the swimming pool water and further aides the dispersion of heat throughout the swimming pool water. Heat is thus transferred from the space 25 to the main body of swimming pool water 5. This intermixing and agitation causes the average temperature of the main body of swimming pool water 5 to increase.

(47) A close-up perspective cutaway view of the swimming pool comprising a solar energy system is shown in FIG. 8 in which the support array and the space between the electrochromic glass and solar radiation receiving panel is shown in greater detail. A row of substantially rectangular solar radiation receiving panels 2 is located within a recess in a curved floor 41 of the swimming pool. The row of panels 2 extends across the entire width of the swimming pool floor 41. The panels comprise a network 43 of longitudinal and lateral tubes within the panels 2 through which fluid flows. An inlet 35 and outlet 36 to the network of tubes 43 is provided at one end of the row of panels 2.

(48) An array of supports 28 sits above the panels. Within the array of supports 28, three support members 70, 71, 72 are located along the width of the row of panels 2 at equal intervals such that two support members 70, 72 are located at either end of the width of the row of panels 2 with a third support member 71 located midway between them. This pattern of three supports is repeated at equal intervals along the entire longitudinal length of the row of panels, thus forming the support array 28.

(49) A row of curved electrochromic glass panes 3 sits above this support array 28 such that the glass panes 3 are supported by the support array 28. This serves to make the glass panes sufficiently supportive and rigid to support the weight of a user of the swimming pool. The glass panes 3 lie flush with the swimming pool floor 41 on either side of the row of panes 3. A gap 26 exists between the row of glass panes 3 and the surrounding swimming pool floor 41 such that water is able to ingress the space 25 between the row of glass panes 3 and the row of panels 2.

(50) A further example of a swimming pool comprising a solar energy system, substantially similar to that shown in FIG. 1, is shown in FIG. 9, in which a cutaway perspective view of the swimming pool is presented.

(51) A row of colinear support members 28, square in cross section, are located at equal intervals along the longitudinal centreline of the row of panels 2. The row of collinear support members 28 extends across the entire length of the row of panels 2.

(52) A curved electrochromic glass pane 3 sits on top of the row of support members 28 such that it is spaced from the panels 2 below. The pane 3 is held at a height such that the uppermost surface of the glass pane 3 lies flush with the uppermost edge 73 of the surrounding swimming pool floor 41 formed by the recess. The perimeter of the glass pane 3 abuts the side faces of the recess within the swimming pool floor 41. The glass pane 3 composes a series of circular apertures 26 arranged around the perimeter of the glass pane 3. The circular holes 26 extend entirely through the thickness of the glass pane 3. When the swimming pool is filled with water, water is permitted to flow between the main body of swimming pool water 5 and the water within the space 25, through the series of circular holes 26 in the glass pane 3.

(53) FIG. 10 shows a close-up cutaway perspective view of the swimming pool comprising a solar energy system of FIG. 1. The system comprises a solar radiation reserving unit 2 and a barrier means of varying solar radiation transmittance 3 arranged over said solar radiation receiving unit 2. For clarity, the water within the swimming pool is not shown.

(54) Four rectangular and substantially planar solar-radiation receiving panels 2 are recessed into the curved section of the swimming pool floor 41 and lie such that they are inclined to the horizontal. The panels each comprise a network of tubes 43 which pass within each panel 2. A fluid inlet 35 to the network of tubes 43 is shown at one end of the row of panels 2. The network of tubes 43 is configured to allow fluid to pass through them.

(55) Curved electrochromic glass panes 3 sit above the panels 2 such that a space 25 is formed between the glass panes 3 and the panels 2. The glass panes 3 are aligned in a row of substantially the same area and coextensive with the row of panels 2. The glass panes 3 are of the same curvature as that of the curved section 41 of the swimming pool floor. The glass panes 3 are spaced above the panels 2 such that their upper surface aligns with the surrounding swimming pool floor 41.

(56) An array of supports 28 sits between the panels 2 and the glass panes 3. Within the array of supports 28, three support members 70, 71, 72 are located along the width of the row of panels 2 at equal intervals such that two support members 70, 72 are located at either end of the width of the row of panels 2 with a third support member 71 located midway between them. This pattern of three supports 70, 71, 72 is repeated at equal intervals along the entire longitudinal length of the row of panels 2, thus forming the support array 28.

(57) An electrical power cable 19 is connected to the electrochromic glass 3 via an electrical connector 74. The electrical connector 74 is received by an electrical connector socket 75. The electrical power cable 74 provides electrical power by which the transmittance of the electrochromic glass panes 3 is varied.

(58) FIG. 11 shows a bracket system 29. The bracket system 29 is hingedly fixed to the swimming pool floor 34. The bracket system 29 comprises a flat rectangular plate 76. The flat plate 76 comprises two hinges 77, 78 located along the panel's length.

(59) Six arms 79-84 of equal length extend from, and in a plane which is substantially parallel to, the perimeter of the bracket's uppermost surface 85. One of the six arms 79, 80, 81, 82 is located in each of the rectangular plate's four corners. The other two arms 83, 84 are located at the centre of both of the plate's longitudinal edges.

(60) The arms 79-84 are configured to receive the electrochromic glass panes. The electrochromic glass panes are not shown for clarity. The electrochromic glass panes may be rotated about the pivot point of the hinges 77, 78 in order to lower the panes into position above solar-radiation receiving panels for maintenance purposes.

(61) FIG. 12 shows the solar energy system similar to that shown in FIG. 1, further composing wireless signal transmitters and wireless signal receivers 31, 32. For increased signal quality, the wireless transmitters and wireless receivers 31, 32 are not submerged within the swimming pool water. The wireless transmitters and receivers 31, 32 form a wireless connection. The wireless connection is used to connect a remote user-operated control unit to the central control unit. The user-operated control unit is used to activate and deactivate the control process. The user-operated control unit also displays the temperature of the swimming pool water and enables the user to specify the desired temperature of the swimming pool water.

(62) FIG. 13 shows the solar energy system of that shown in FIG. 1, further comprising a swimming pool structure 59 with substantially reflective walls 33. Although not shown, the walls within the recess may also be substantially reflective. The substantially reflective walls 33 of the swimming pool increase the available quantity of solar radiation incident on a row of four rectangular and substantially planar solar-radiation receiving panels 2.

(63) In an alternative embodiment (not shown) the system could be used without the barrier means with the pump being used to pump water around the secondary circuit when a temperature below around 45 degrees centigrade is reached and the solar radiation receiving unit being used to heat the water either directly or via a heat exchanger in the secondary circuit.

(64) While the embodiments described have been shown in combination and placed in a swimming pool, the solar energy system could be used placed away from the swimming pool for example on a roof and used to heat water pumped within the solar radiation receiving unit or by pumping a heat transfer fluid to a heat exchanger arrangement to heat water to be provided to a swimming pool or any other appliance requiring hot water.

(65) The applications of the system of the present invention include roof top heating systems, heating systems on boats and ships where heating water using fossil fuels or electricity is inefficient or requires fuel to be transported. The present system allows ‘free’ solar energy to be utilised in an advantageous manner.

(66) It is envisaged that the skilled person in the art may make various changes to the embodiments specifically described above without departing from the scope of the invention.