WO2021108839A1

WO2021108839A1 - A cladding element

Info

Publication number: WO2021108839A1
Application number: PCT/AU2020/051277
Authority: WO
Inventors: Zhong TAO; Md Abdul Alim; Ataur Rahman; Md Kamrul Hassan; Bijan Samali
Original assignee: University of Western Sydney
Current assignee: University of Western Sydney
Priority date: 2019-12-04
Filing date: 2020-11-26
Publication date: 2021-06-10
Anticipated expiration: 2022-06-04

Abstract

A cladding element (10) includes a body member (12) of a cementitious material, the cementitious material containing a phase change material (PCM). A renewable resource energy generating member (14) is carried by the body member (12).

Description

"A cladding element"

Cross-Reference to Related Applications

[0001] The present application claims priority from Australian Provisional Patent Application No 2019904585 filed on 4 December 2019, the contents of which are incorporated herein by reference in their entirety.

Technical Field

[0002] This disclosures relates, generally, to cladding of a structure and, more particularly, to a cladding element.

Background

[0003] There is an increasing interest in integrating photovoltaic (PV) cells in building components, such as roof tiles. However, PV conversion efficiency is adversely affected when the PV cell temperature gets too high. In addition, prospective systems are expensive due to their complex structural designs and installation processes.

[0004] Based on current technology, however, only about 15 - 24% of the incident solar energy can be converted into electricity by PV cells. At the same time, these cells also absorb the infrared component of the solar irradiance, which increases the panel temperature and adversely affects the PV conversion efficiency. It is estimated that the conversion efficiency could decrease by up to about 0.8% on average with every 1°C temperature rise. The increase in temperature of the PV cells on a surface such as a roof of a building also has adverse temperature effects on the indoor environment.

[0005] Researchers have explored different methods to control PV cell panel temperature and the use of phase change material (PCM) has been identified as an option. A suggested method of using PCM involves attaching a component with PCM at the back of a Building Integrated Photovoltaics (BIPV) panel, the PCM containing component absorbing heat isothermally and keeping the panel temperature low. However, the required engineering for this idea to be practically implemented is relatively complex. For example, researchers have tested the idea of BIPV/PCM systems with a ventilation unit where a PCM container was placed at some distance from the back surface of the BIPV panel. The system allowed air to pass through the gap between the BIPV panel and the PCM container to absorb heat. The process cooled down the BIPV system significantly and the hot air was used for space heating and drying. Nonetheless, the process increased the weight and cost of the BIPV system, which is one of the major barriers hindering the adoption of this technology. The performance of a double skin facade (DSF), which included an integrated layer of PV cells upon another layer of PCM has also been investigated. The dynamic thermal behaviour of the system was evaluated under different climate conditions, such as Venice, Helsinki and Abu Dhabi. It was found that attaching a PCM layer beneath a semitransparent PV layer could reduce the cooling energy demand by 20 - 30 % monthly.

[0006] It has also been reported that employing a PCM layer on the outer surface of the facade could improve energy efficiency by 10 - 12%. Further, it has been reported that incorporating PCM with a ventilated PV facade decreased the panel temperature by 20 °C on extremely hot days. Researchers have examined the electrical and thermal performance of a BIPV system, where ventilation was provided between the BIPV system with a PCM layer and the building wall. It was reported that the height of the BIPV, air flow rate and PCM layer thickness were the primary factors influencing the overall performance. However, all these methods require additional support structures and a large amount of PCM which significantly increases the total cost of each of such systems.

[0007] The incorporation of PCMs in construction materials has been extensively studied to improve the energy efficiency of buildings by reducing the heating/cooling loads. However, all those studies have suggested that further research is needed to identify the appropriate methodology of PCM incorporation in building components and subsequent evaluation of the performance of those components. [0008] Furthermore, concerning the cost of any such prospective system, a large portion of the cost is associated with an intricate integration process resulting in a lengthy manufacturing time, complex installation requirements, the requirement of racking and structural rail component that are expensive, high labour cost and the requirement of a cooling system.

[0009] Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each of the appended claims.

Summary

[0010] According to an aspect of the disclosure, there is provided a cladding element which includes a body member of a cementitious material, the cementitious material containing a phase change material (PCM); and a renewable resource energy generating member carried by the body member.

[0011] The cementitious material may include at least 2% by weight of the PCM.

The PCM may be a form stable PCM (FSPCM). The FSPCM may include the PCM incorporated into a carrier. The carrier may be a silica based material. For example, the silica-based material may be diatomite, perlite, graphene, or the like.

[0012] The cementitious material may include approximately one part cement to two parts of a sand mixture, the FSPCM, in an embodiment, forming about 10% of the sand mixture; and about one part liquid to about two parts cement. In other embodiments, the FSPCM could constitute anywhere from approximately 20%-30%to approximately 40%-50% of the sand mixture. [0013] The body member may define a receiving formation in which the energy generating member is receivable. The receiving formation may be a recess defined in a surface of the body member.

[0014] The renewable resource energy generating member may be a photovoltaic cell array having a plurality of one of monocrystalline solar cells, amorphous silicon cells, copper indium gallium diselenide cells, and perovskite cells.

[0015] The element may include a protective member applied to the body member for protecting the energy generating member. The protective member may be transparent to light (both in the visible spectrum and the infra-red (IR) spectrum). In an embodiment, the transparent member may be a tempered or toughened glass member which is able to withstand the elements. It will, however, be appreciated that the protective element could be of a suitable synthetic plastics material such as, for example, an acrylic material.

[0016] In an embodiment, the energy generating member may, in an initial manufacturing step, be bonded to the protective member to form a pre-cast module.

The pre-cast module may then be received in the recess of the body member to simplify and speed up the manufacturing process with resultant manufacturing cost benefits.

[0017] The cementitious material of the body member may include one of a hydrophobic material and a hydrophilic material mixed in with the cementitious material.

[0018] At least an operatively upper surface of the body member may include a coating of a reflective material.

[0019] In an embodiment, the cementitious material may contain at least two PCMs, the PCMs having a phase change characteristic different from one another.

[0020] The element may be in the form of a roof tile. Brief Description of Drawings

[0021] An embodiment of the disclosure is now described by way of example with reference to the accompanying diagrammatic drawings in which: -

[0022] Fig. 1 shows a schematic, exploded perspective view of an embodiment of a cladding element;

[0023] Fig. 2 shows a perspective view of a prototype of the cladding element;

[0024] Fig. 3 shows a graph of power generation of the embodiment of the cladding element versus a control solar roof tile;

[0025] Fig. 4 shows a graph of variation in outside temperature for the cladding element versus the control solar roof tile and a regular roof tile;

[0026] Fig. 5 shows a graph of variation in internal temperature, within a structure, for the cladding element versus the control solar roof tile and the regular roof tile;

[0027] Fig 6 shows a schematic, exploded view of another embodiment of the cladding element;

[0028] Fig. 7 shows, on an enlarged scale, a part of the cladding element bounded by the dashed line box labelled ‘A’ in Fig. 6;

[0029] Fig. 8 shows a schematic representation of the electrical interconnection of a plurality of the cladding elements;

[0030] Fig. 9 shows a further experimental setup used to test the cladding element; and [0031] Fig. 10 shows a graph of temperature and irradiance versus time for the cladding element in the experiment of Fig. 9 versus a reference roof tile and a control solar roof tile.

Detailed Description of Exemplary Embodiments

[0032] In the drawings, reference numeral 10 generally designates an embodiment of a cladding element. In the described embodiment, the cladding element is a roof tile 10 and will be described with reference to that application below. It will, however, be appreciated that the cladding element could adopt other forms, for example, wall cladding, building facades, decorative structures for buildings, or the like.

[0033] The roof tile 10 comprises a body member 12 of a cementitious material. The cementitious material contains a phase change material (PCM). A renewable resource energy generating member in the form of a photovoltaic (PV) cell array 14 is carried by the body member 12.

[0034] More particularly, the body member 12 defines a recess 16 within which the PV cell array 14 is received. The PV cell array 14 is retained in position within the recess 16 of the body member 12 by a layer of suitable adhesive material (not shown). An operatively upper, or outer, surface of the PV cell array 14 is covered by a further impervious, transparent adhesive layer 18. A transparent protective member, in the form of a layer of toughened glass, 20 is applied to the adhesive layer 18 to protect the PV cell array 14 against the elements, in use.

[0035] The PCM used in the body member 12 of the roof tile 10 is of the type which changes from a solid-state to a liquid state with increased temperature. In an embodiment, the PCM is selected to have a melting temperature approximating that of a surface temperature of the body member exposed to sunlight on a relatively cool day. The PCM selected is methyl stearate having a melting temperature of approximately 36.5°C. [0036] However, the Applicants also envisage that, in another embodiment, multiple PCMs with different melting points could be used. For example, one of the PCMs could be methyl stearate having the melting point of approximately 36.5°C while a second PCM could be sodium acetate having a melting point of approximately 48°C. Those skilled in the art will appreciate that, in other embodiments, different PCMs could be used.

[0037] To inhibit leakage of the PCM from the body member 12, the PCM used in the cementitious material, or mix, of the body member 12 is a form-stable PCM (FSPCM). A FSPCM has the further advantage that heat transfer is enhanced.

[0038] In preparing the FSPCM, the PCM, in solid form, is incorporated into a carrier. The carrier is of a silica based material. Examples of silica based material which could be used include diatomite, perlite, or the like. In the present case, diatomite was used with the PCM incorporated into pores of the diatomite.

[0039] To fabricate the FSPCM, a predetermined quantity of diatomite is placed in a glass vessel and heated to 60°C. Solid PCM is heated to the same temperature in a dropping funnel placed above the glass vessel. A chamber of the glass vessel is then evacuated using an evacuation pump to remove air from the pores of the diatomite. After complete melting of the PCM, the PCM is added to the diatomite in a drop wise manner with an electric stirrer being used for mixing. The process is considered as completed when all the liquid PCM had been absorbed entirely into the porous diatomite and the PCM has been allowed to solidify.

[0040] The set FSPCM is then used in the preparation of the body member 12 of the roof tile 10. This is effected by mixing fine sand, cement and water to make the cementitious mixture, or mortar. The FSPCM is mixed in with the sand in the proportion of 10%, by weight, of the sand and so that the FSPCM constitutes, in total, about 2% of the mortar. The cement is mixed with the sand in the ratio of one part cement to two parts sand. Prior to the addition of water to the mixture, the sand, cement and the FSPCM are mixed together for approximately 5 to 10 minutes until the FSPCM is uniformly dispersed in the mixture. Water is then added to the mixture in the required quantity being approximately one part water to two parts cement.

[0041] The final mixture of the mortar is poured into a mould, such as, for example, a 3D-printed mould, and is allowed to set. The mortar is cured for approximately 28 days.

[0042] After curing of the mortar, the body member 12 is removed from the mould. The PV cell array 14 is bonded in position in the recess 16 of the body member 12 using an epoxy adhesive. The PV cell array 14 is comprised of silicon monocrystalline solar cells. The adhesive layer 18 is applied to cover the PV cell array 14. The adhesive layer 18 is moisture impervious to inhibit water ingress and, therefore, to inhibit damage to the solar cells of the array 14 by moisture.

[0043] The protective glass layer 20 is then applied to the adhesive layer 18, the protective glass layer 20 serving to inhibit damage to the array 14 which may arise as a result of environmental conditions. As indicated above, the glass layer 20 is made of toughened glass to withstand environmental conditions such as hailstorms, etc.

[0044] The cementitious material from which the body member 12 is made can, optionally, incorporate a hydrophobic material, more particularly, a cementitious-based hydrophobic material. Instead, the body member 12 may be coated with a hydrophobic material. This will serve to discourage moisture retention on the body member 12. An example of a suitable hydrophobic material is XYPEX^® Admix C - 1000 NF (XYPEX is a Registered Trade Mark of Xypex Chemical Corporation, 13731 Mayfield Place, Richmond BC, V6V 2G9, Canada).

[0045] Another approach is to use a hydrophilic material that is incorporated into the mortar of the body member 12 to inhibit damage to the mortar by moisture. An example of a suitable hydrophilic material is Krystol^® Internal Membrane™ (KIM^®: K- 301) (Krystol and KIM are Registered Trade Marks of KHI Capital Inc., 1645 East Kent Avenue, BC V5P 2S8, Canada). [0046] Still further, the body member 12 includes a coating of a reflective material to enhance reflectivity of the body member 12 of the roof tile 10. As a result, the temperature of the body member 12 is further reduced, in use, and, in so doing, further improves the efficiency of the PV cell array 14. An example of a suitable coating of reflective material is Solacoat^®. (Solacoat is a Registered Trade Mark of Cool Shield Pty Ltd (CAN: 102 333 577) of 34-50 Nathan Road, Dandenong South, VIC, 3175, Australia).

[0047] As a further development of the roof tile 10, the glass layer 20 may be oppositely charged at its ends to create a voltage differential over the surface of the layer 20. This serves to cause dirt and other particles to be attracted to the opposite ends of the layer 20 imparting at least a partial self-cleaning effect to the layer 20.

Examples

[0048] An initial experimental setup of a roof tile 10 was constructed using a body member 12 having the cementitious mixture described above. The roof tile 10 carried a PV cell array 14 comprising two cells connected by tab and bus wires. The nominal energy conversion efficiency of each of the solar cells was 17% according to the supplier. In the experimental setup, three different tiles were prepared: a reference roof tile (RRT) of the same cementitious mixture but without the PV cell array 14 applied thereto, a control solar roof tile referred to as a typical solar roof tile (TSRT) of a cementitious mixture without PCM but with a PV cell array applied to a surface thereof and the roof tile 10, as described above.

[0049] Two type-T thermocouples were used to measure the temperature of the top, or outer, surface and the bottom, or inner, surface of each tile. A total of six thermocouples were used in the experiment and the tile temperatures were recorded every 30 minutes by a data logger. The ambient temperature data throughout the day were obtained from a weather station approximately 7 km away to provide representative field temperature data. [0050] An Apogee pyranometer (model SP-110) was pre-calibrated and used to measure solar irradiance. A digital multimeter was used to measure electrical quantities, such as voltage and current, the measurements being taken hourly. The 3 tiles were arranged alongside each other and the pyranometer was placed next to the tiles to ensure that the intensity of solar irradiance was concurrently recorded.

[0051] The initial experiment was conducted on the Kingswood Campus of Western Sydney University, Sydney, Australia having coordinates of 33°45'49.6"S; 150°43'13.8"E. All the tiles were placed facing north with a tilt angle of 33°, being the optimum orientation for solar energy reception at that location. The tests were conducted on sunny, Southern Hemisphere early winter days of 8 May 2019 and 12 May 2019 between 7:30 AM and 3:00 PM to confirm reproducibility of the data. Due to very similar results being obtained from the measurements conducted on the two days, only the results obtained on 8 May 2019 were analysed further.

[0052] The tiles were tested for their energy generation capacity and heat transfer characteristics in relation to an interior volume of a structure on which such tiles would be applied. Another factor that the experiment sought to investigate is the microclimate change or heat island effect caused by PV systems. Such systems cause temperature increases arising from the infrared component of solar irradiation. The heated PV systems heat the surrounding air and this is known as the heat island effect. The determination of microclimate change arising from installation of solar roof tiles is very complex because of the integration of the PV cells into the roof surface. Any structure having a roof naturally interferes with heat absorbed or reflected from the earth.

[0053] In the Applicants’ study, only convective heat transfer from the outside roof surface to the environment was investigated to understand the roof tile heat island effect of both a TSRT and PCMSRT in the daytime instead of microclimate change.

[0054] With reference to the results of the investigation, Fig. 3 of the drawings shows a graph representing power generation by the TSRT and the PCMSRT. Curve 22 represents the power generated by the TSRT while curve 24 represents the power generated by the PCMSRT. The curves 22 and 24 show that the power generation capacity of the two types of tiles were generally similar in the early morning but, as time passed, the increase in power generation of the PCMSRT relative to the TSRT became noticeable. The maximum power differential between the PCMSRT and the TSRT occurred between about 10:00 AM and 11:00 AM with the PCMSRT showing higher electrical performance almost throughout the day.

[0055] It is noted that the electrical power generation of the two tiles dropped to similar levels at around 2:00 PM and this was due to the surface temperatures of the two tiles becoming similar at that time. The total electrical energy generated from the two tiles between 8:00 AM and 2:00 PM were 33.57 Wh for the TSRT versus 36.82 Wh for the PCMSRT. This is an improvement of about 4% in energy generation by the PCMSRT relative to the TSRT.

[0056] The Applicants are of the view that this improvement is due to the enhancement of the thermal mass of the PCMSRT due to incorporation of the FSPCM in the body member 12 of the roof tile 10. An improvement in the thermal mass results in a reduction of surface temperature which, ultimately, causes an increased power generation capacity of the PCMSRT relative to the TSRT.

[0057] As described above with reference to Fig. 3 of the drawings, the power generated by the TSRT dropped after approximately 10:00 AM. Referring now to Fig. 4 of the drawings, a graph of temperature profiles of the outer surfaces of the three roof tiles is illustrated. In Fig. 4 of the drawings, curve 26 represents the temperature profile of the outer surface of the RRT, curve 28 represents the temperature profile of the outer surface of the PCMSRT and curve 30 represents the temperature profile of the outer surface of the TSRT over time.

[0058] It is noted from those curves that, at the commencement of the measurements, the temperature differential between the three roof tiles was negligible. However, the surface temperature of the TSRT increased rapidly in comparison with the surface temperatures of the RRT and PCMSRT with time. The Applicants believe that the temperature rise of the TSRT relative to the RRT was due to the incorporation of PV cells into the TSRT which absorbs the infrared component of the solar irradiation and converts the infrared radiation into heat. Although the PCMSRT could induce a similar effect due to the incorporation of PV cells, the lower temperature of the outer surface of the PCMSRT is attributable to the enhanced thermal mass arising from the incorporation of FSPCM into the body member 12 of the roof tile 10.

[0059] The surface temperature difference between the TSRT and RRT could be as high as 5.2°C and the average difference was approximately 3°C during the day. Conversely, the temperature difference between the PCMSRT and the RRT was insignificant being a maximum difference of about 0.8°C and an average difference of about 0.39°C during the day.

[0060] The thermal performance of the roof tiles was evaluated by determining convective heat transfer from the roof tiles to a hypothetical indoor environment as well as to the surroundings. The investigation was to determine whether or not, by incorporating PCM inside solar roof tiles, a cooler indoor environment (with the potential of saving on cooling energy) and a reduction in the local heat island effect could be achieved.

[0061] Fig. 5 of the drawings shows a graph of measured inner surface temperature of each of the different roof tiles, this having a direct impact on building energy consumption. Curve 32 shows the inner surface temperature of the RRT, curve 34 shows the inner surface temperature of the PCMSRT and curve 36 shows the inner surface temperature of the TSRT over time. It is noted that, during the measurements, the inner surface temperatures of the tiles reached a peak at approximately 12:30 PM but that those temperature peaks were different.

[0062] In general, the RRT had the lowest inner surface temperature, the TSRT had the highest inner surface temperature while the inner surface temperature of the PCMSRT was higher than that of the RRT but lower than that of the TSRT. The average temperature difference between the TSRT and the PCMSRT with respect to the RRT were 5.5°C and 4.2°C, respectively. The maximum temperature difference between the TSRT and RRT was 7.2°C while the corresponding value for the PCMSRT relative to the RRT was 5.8°C. This is to be expected since there is a rising inner surface temperature for solar roof tiles, possibly necessitating increased cooling energy requirements in hot weather. Nevertheless, the investigation illustrates that the provision of FSPCM in the body member 12 of the roof tile 10 reduces the need for increased cooling energy requirements.

[0063] With respect to local roof tile heat island effects and generation of convective heat transfer from the outer surface of the roof tiles to the surroundings, the experiment showed that the convective heat transfer from the outer surface of the PCMSRT to the surroundings was comparable to that of the RRT but was approximately 14% lower in comparison with the TSRT. The Applicants are of the view that this could be used to promote the advantages of the PCMSRT to local communities and local governments which may be concerned with the heat island effect of solar roof tiles.

[0064] It is therefore an advantage of the disclosed embodiment that a roof tile 10 is provided which, in comparison with a solar roof tile without PCM incorporated therein, provides an increase in power generation of about 4% whilst, simultaneously, having significantly lower convective heat transfer, both externally and internally, than the solar roof tile without PCM incorporated therein. In addition, the roof tile 10 has similar characteristics to a regular roof tile, i.e. without PV cells, at least insofar as external convective heat transfer is concerned.

[0065] Referring now to Figs. 6 and 7 of the drawings, a further embodiment of the cladding element in the form of a roof tile 10 is illustrated and described. With reference to previous drawings, like reference numerals refer to like parts unless otherwise specified.

[0066] In this embodiment, the tile 10 includes the cementitious body member 12 defining the recess 16. The PV cell array 14 forms part of a module 40 received in the recess 16 of the body member 12. The module 40, as illustrated in greater detail in Fig. 7 of the drawings, comprises a layer of adhesive in the form of an epoxy 42 applied to an operatively lower surface of the PV cell array 14. The epoxy 42 is used for securing the module 40. within the recess of the body member 12. A protective fdm 44 of a suitable synthetic plastics material, such as, for example, an ethylene vinyl acetate (EVA) fdm, is applied to the PV cell array 14. The protective layer 20 in the form of a layer of toughened, or tempered, glass is then applied to the EVA fdm 44 to form the module 40 received in the recess 16 of the body member 12.

[0067] Prior to installation of the module 40, at least the operatively top, or outer, surface of the body member 12 of the roof tile is treated with a coating of reflective material. If desired or appropriate the entire surface of the body member 12 is treated with the coating of reflective material. Optionally, where transparent solar cells are used in the PV cell array, the surface of the module 40 itself could also be coated with a reflective coating.

[0068] Any gap between the periphery of the module 40 and the boundary of the recess 16 is sealed using a suitable sealant such as a silicone sealant or glue to inhibit ingress of moisture and other detritus. It will be appreciated that, by forming the module 40, assembly of the roof tile 10 is facilitated reducing manufacturing costs and speeding up the manufacturing process.

[0069] In this embodiment, the tile 10 includes a pair of conductive connectors, in the form of connecting pins 46. The pins 46 are arranged at opposed ends of the module 40 extending from an operatively underside of the module 40. One of the pins 46 is a positive connector and the other of the pins 46 is a negative connector. Further, the module 40 includes a pair of opposed locators, each in the form of a locating pin 48.

The locating pins 48 are arranged on opposed sides of the module 40 extending orthogonally from the operatively underside of the module 40.

[0070] The recess 16 of the body member 12 of the tile 10 defines a pair of opposed conductive receivers, or sockets 50, in which the connecting pins 46 of the module 40 are received. Further, the recess 16 defines a pair of opposed receiving sockets 52 in which the locating pins 48 of the module 40 are received.

[0071] Fig. 8 shows a schematic representation of the interconnection of a plurality of the roof tiles 10 on a roof 54. The roof 54 has a plurality of spaced, parallel battens 56, two of which are shown. Each batten 56 supports an electrical mounting bar 58. One of the mounting bars 58 has a positive terminal 60 and a negative terminal 62 between which a plurality of discrete, spaced electrically conductive links 64 are arranged. Each terminal 60, 62 extends from a socket 63 defined in the mounting bar 58 carrying the terminals 60, 62. Each end of each link 64 terminates in a socket 66. The other of the mounting bars 58 only has the plurality of spaced, discrete links 64, with associated sockets 66, on it. The links 64 on the first of the mounting bars 58 are staggered with respect to the links 64 on the second of the mounting bars 58.

[0072] Fig. 8 shows two roof tiles 10 in accordance with this disclosure, each roof tile 10 being shown in a front view and a side view and spaced from the roof battens 56, i.e. prior to being mounted on the battens 56. It will be appreciated that, in use and as described in greater detail below, a series of roof tiles 10 are interconnected along the battens 56 of the roof 54. As described above, each roof tile 10 has a pair of spaced connecting pins 46 at, or proximate, opposed ends of the module 40. The connecting pins 46 project through the body member 12 of the tile 10 to be accessible from an operatively rear side of the body member 12.

[0073] In respect of each roof tile 10, one of the pins 46.1 is a positive pin and the other of the pins 46.2 is a negative pin. In respect of the first of the roof tiles 10, its positive pin 46.1 is received in the socket 63 associated with the positive terminal 60 on the mounting bar 58. The negative pin 46.2 of that roof tile 10 is received in a first socket 66 of the first link 64 on the other of the mounting bars 58. Roof tiles 10 are sequentially mounted in opposite orientation with respect to their positive and negative pins 46 on the roof battens 56 until, in respect of the last of the roof tiles 10 on that pair of battens 56, the negative pin 46.2 of the roof tile 10 is received in the socket 63 associated with the negative terminal 62 and the positive pin 46.1 is received in the last socket 66 of the last of the links 64 on the other of the roof battens 56 to form a series connected arrangement of PV cell arrays 14 of the roof tiles 10.

[0074] Further experiments were conducted at the same venue as the initial experiment in the Southern Hemisphere summer days of 28 December 2019 to 2 January 2020, once again between the hours of 7:30 AM and 3 PM to confirm reproducibility of the data.

[0075] The experimental setup used in the further experiments is as shown in Fig. 9 of the drawings. Once again, the roof tile 10 was compared with a reference roof tile (RRT) 68 as well as a control, typical solar roof tile (TSRT) 70. Each of the tiles 10,

68 and 70 were mounted on a polystyrene box 72. The polystyrene box 72 can be regarded as representing the underlying structure, such as a building, on which the tile 10, 68 or 70, as the case may be, would be mounted and allows internal temperatures to be taken. The equipment used in monitoring the tiles 10, 68 and 70 was as described above with reference to the initial experiment.

[0076] Fig. 10 shows a graph representing temperature as measured within each polystyrene box 72 of the experimental setup described above with reference to Fig. 9 of the drawings. In Fig. 10, curve 74 shows the temperature profde of the RRT 68, curve 76 shows the temperature profde of the roof tile 10 and curve 78 shows the temperature profde of the TSRT 70. The circular indicia 80 represent irradiance of the roof tiles 10, 68 and 70.

[0077] It will be noted from the graph of Fig. 10 that the roof tile 10, with its reflective coating, reduces the temperature within the polystyrene box 72 by up to 7°C and is comparable with the RRT 68. Thus, the need for increased cooling energy requirements resulting from the use of PV solar arrays 14 is obviated, or at least substantially reduced, using a roof tile 10 including reflective coating.

[0078] It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the above-described embodiments, without departing from the broad general scope of the present disclosure. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

CLAIMS:

1. A cladding element which includes a body member of a cementitious material, the cementitious material containing a phase change material (PCM); and a renewable resource energy generating member carried by the body member.

2. The element of claim 1 in which the cementitious material includes at least 2% by weight of the PCM.

3. The element of claim 1 or claim 2 in which the PCM is a form stable PCM (FSPCM).

4. The element of claim 3 in which the FSPCM includes the PCM incorporated into a carrier.

5. The element of claim 4 in which the carrier is a silica based material.

6. The element of any one of the preceding claims in which the cementitious material includes approximately one part cement to two parts of a sand mixture, the PCM forming about 10% of the sand mixture; and about one part liquid to about two parts cement.

7. The element of any one of the preceding claims in which the body member defines a receiving formation in which the energy generating member is receivable.

8. The element of claim 7 in which the receiving formation is a recess defined in a surface of the body member.

9. The element of any one of the preceding claims in which the renewable resource energy generating member is a photovoltaic cell array.

10. The element of any one of the preceding claims which includes a protective member applied to the body member for protecting the energy generating member.

11. The element of claim 10 in which the protective member is transparent to light.

12. The element of any one of the preceding claims in which the cementitious material of the body member includes one of a hydrophobic material and a hydrophilic material mixed in with the cementitious material.

13. The element of any one of the preceding claims in which at least an operatively upper surface of the body member includes a coating of a reflective material.

14. The element of any one of the preceding claims in which the cementitious material contains at least two PCMs, the PCMs having a phase change characteristic different from one another.

15. The element of any one of the preceding claims which is in the form of a roof tile.