WO2022038398A1

WO2022038398A1 - Attachable solar thermal window

Info

Publication number: WO2022038398A1
Application number: PCT/IB2020/057808
Authority: WO
Inventors: Masoud Valinejadshoubi; Alireza ALIAKBAR ALHOSSEINI; Behrouz TAVAKOLI KHORASANI; Navid ASSADI
Original assignee: Masoud Valinejadshoubi
Priority date: 2020-08-19
Filing date: 2020-08-19
Publication date: 2022-02-24

Abstract

A solar thermal window structure is configured to form a principal chamber enclosing an inner window pane installed in an exterior wall of a building. The solar thermal window structure includes semitransparent-Photovoltaic panel and porous-metal sheets absorbing solar radiation, air channels to extract the temperature of semitransparent-Photovoltaic panels and porous-metal sheets through airflow, outer window installed on the mainframe; these components are tilted in an optimum degree to make shade on the inner window in summer and absorb solar radiation in winter. The first position of the solar thermal window is a solar air heater where the air source of the system comes from building indoor through an opening panel, and after getting temperature, comes back to the indoor. In the second position, the heating process is stopped and also the inner and outer windows can be opened to make natural ventilation.

Description

Attachable Solar Thermal Window

Description

TECHNICAL FIELD

[0001] The present application generally relates to an attachable window structure capable of absorbing solar energy to convert to electricity and thermal for users’ demands in buildings. In particular, the present application relates to the structure to generate electricity and thermal energy and controlling solar radiation for building indoor by making shade on the inner window.

BACKGROUND

[0002] Sources of renewable energies, in comparison with other sources of energy that are concentrated in the limited number of countries, provide us with significant opportunities for economizing in consumption of energy in vast geographical areas, accompanied with energy security for the countries through leaning on interminable domestic sources, increasing of sustainability, reduction of air pollution and climate changes.

[0003] A considerable proportion of global energy consumption and greenhouse gas emissions are buildings, which is even more than industry and transportation energy usages, almost one-third of the world's energy. Among different parts of the building, electrical lighting, heating, and cooling represent a large amount of energy consumption. International Energy Agency (IEA) reported that “worldwide, grid-based electric lighting consumes 19% of total global electricity production” and that “on average, lighting accounts for 34% of tertiary-sector electricity consumption”. Commercial & Institutional Consumption of Energy Survey (CICES) estimates that commercial and institutional establishments in Canada consumed over 1036 million GJ. This total corresponds to the annual consumption of some nine million Canadian households or the equivalent of nearly twice the energy consumption of all private households in Ontario

[0004] To become zero energy or zero-emission building, harvesting energy from its surroundings is needed, where energy from the sun is one of the obvious choices, which is abundant in both direct and indirect forms. The sun emits energy at a rate of 3.8xl0²³ kW per second. Of this total, only a tiny fraction, approximately 1.8xl0¹⁴ kW, is intercepted by the earth. The solar energy can be used in buildings in different forms, such as heating, cooling, and electricity. Solar energy utilization can be divided into two fields: solar thermal and photovoltaic. Solar thermal is mainly concerned with the utilization of solar radiation to provide useful heating. A new and promising way to integrate renewable energies in the constructed environment is to integrate photovoltaic technologies in buildings. Building-integrated photovoltaic (BIPV) became one of the fastest-growing segments of the solar industry worldwide, with capacity growth of 50% from 2011 to 2017.

[0005] One of the main disadvantages of heating products using solar energy at the global level is that they use a unidimensional prospect and are not combined with other systems. Many of these systems only deal with the heating of air while neglecting other aspects such as the light received by the internal space or the view of the residents of the buildings. And also, the solar thermal systems, because of low efficiency, need a large installation to meet users’ demand in a building, and finally, solar thermal products are not enough integrated with building facade, causing reluctant users to use on their buildings.

SUMMARY

Disclosed is a solar thermal window structure configured to form a principal chamber enclosing a first window pane installed in an exterior wall of a building. The solar thermal window structure includes a main frame including a sliding window pane with its frame, tilted Photovoltaic panels, porous surface, and Phase Change Material (PCM) surface. Photovoltaic panels may be placed above and below the structure, which is tilted in an optimum yearly degree to block solar radiation in summer to decrease cooling demand and absorb maximum solar radiation in winter besides allowing some portion of radiation to reach indoor to decrease heating demand. Photovoltaic panels are semitransparent on which some portion of solar radiation may be passed. At the back of the Photovoltaic panel, two air channels may be placed, separated by a porous metal sheet. Air channels allow air to flow. When Photovoltaic panels absorb solar radiation, some portions of this radiation can be converted to electricity, but most of the absorbed solar radiation may be wasted through heating the Photovoltaic panels. The heated Photovoltaic panel has a lower efficiency than the cold one. And also, the semitransparent Photovoltaic panels allow some portions of solar radiation to reach the porous material in the air channel, causing to increase the temperature of the porous metal sheet. The airflow in channels may extract temperature from two main heat transfer sources (Photovoltaic panels, and porous metal sheet) to be heated up. The airflow in the channel may decrease the temperature of the Photovoltaic panel, causing to increase in electrical conversion efficiency, besides raising heated air generation. The porous metal sheet allows two air channels to be connected, which can be effective in raising the heat transfer coefficient and thermal generation. The air in channels comes from the indoor building through an entrance box below of the window, and heated air may go back to the indoor through a box above the window, including a fan and air filter. The fan can help air to flow in an appropriate velocity in the system. The appropriate air velocity may be different in seasons and building functions, which can be balanced by the fan speed. After sucking the air from the system through the fan, the air may be passed from the air filter to increase the quality of indoor air. In the air channel, there is a PCM panel to increase air channel temperature in different solar radiation rates. Through the heating process in air channel, PCM panel gets latent temperature up, and its phase is changed from solid to liquid, and when the solar radiation is not enough or at night, the PCM panel give temperature to the air channel as a heat transfer source and its phase come back to solid. There are valves in channels to block the channel from airflow whenever there is not any need to heat air temperature for building usage. The internal and external windows can be open when the valves are closed to have access to outside and increase natural ventilation.

[0006] In certain cases, the Photovoltaic panel is a black one. In some examples, the semitransparent Photovoltaic panel has 0.7 Packing Factor.

[0007] In some examples, solar thermal window structures may not have a fan to transmit the air warmed by the energy-absorbing surface from the interior space of the principal chamber to the interior of the building.

[0008] Certain example window structures may also include a heating element disposed on or near the fan. If the energy absorbed by the heat transfer sources is not sufficient to warm air to a certain temperature, the air may be warmed by the heating element, and the fan may transmit the air warmed by the heating element to the interior of the building. These solar energy cells may produce energy that can power the heating element

[0009] In certain cases, the fan, which may be located on the top portion of the inside window pane, may also be used to transmit the warm air, warmed within the principal chamber, into the interior of the building. Simultaneously, the cold air may be transmitted from the interior of the building into the principal chamber through the bottom portion of the inside window for further warming and reaching the desired temperature.

[0010] In some examples of the disclosed solar thermal window structure, the mainframe and the exterior window pane may have exterior surfaces facing outward of the building. The exterior window may be in a closed position when the building needs heated air, and the exterior window may be in an open position when the building does not need heated air, and users need to have access to outdoor.

[0011] The enclosed place that the solar thermal window structure provides between indoor and outdoor may decrease thermal transmittance and infiltration between indoor and outdoor, causing to save energy.

[0012] In certain cases, the window structure may include a distributing panel in the interior of the building. The distributing panel may include the heating element. The distributing panel may also include an electrical energy storage element that can supply electrical energy to the heating element and building applications. Furthermore, there is a panel which may be located in the bottom portion of the inner window pane, which may transmit the air from the interior of the building to the principal chamber to warm the air.

[0013] Also disclosed is a method of forming a window structure to form a principal chamber enclosing a first window pane installed in an exterior wall of a building. The method includes providing a mainframe. The mainframe includes an exterior window, semitransparent Photovoltaic panels, porous metal sheets, and air channels. The method further includes attaching the mainframe to the exterior wall of the building to tilt about a first axis disposed at a first distance from the inner window pane, such that the mainframe may be tilted in an optimum degree to make shade on the interior window and absorb solar radiation in winter. Semitransparent Photovoltaic panels and porous metal sheet as energy- absorbing surfaces are attached to a location between exterior and interior windows in an enclosed place. In back channels, there are PCM panels to decrease temperature fluctuations in the channel and act as a heat transfer source at night or whenever the solar radiation is not enough.

[0014] The disclosed solar thermal window is multipurpose, and it is easy to construct and maintenance in its lifetime. In certain cases, where increasing the internal temperature of the building is needed, the proposed window may be in a solar air heater position through opening the valves in air channels. When reduction of internal temperature is needed, the valves are closed, and airflow in the channel is stopped, and by opening the windows with different rates, the amount of air current and the reduction of internal temperature can be controlled.

[0015] One application of the disclosed window may be to use solar radiation to generate thermal and electrical energy, as well as using shade and natural ventilation to decrease indoor temperature whenever it is needed. [0016] An object is to design a solar thermal window to achieve spatial comfort through heating and cooling. This window can be used in all climates and different regions with various needs of heat and ventilation. And also, this solar thermal window may be used in existing and new buildings, and easy to assemble and install.

BRIEF DESCRIPTION OF DRAWINGS

[0017] The drawing figures depict one or more implementations in accord with the present teachings, by way of example only, not by way of limitation. In the figures, like reference numerals refer to the same or similar elements.

[0018] FIG. 1 is a top front right-side perspective view of an example solar thermal window structure, including semitransparent Photovoltaic panels, mainframe, and exterior window.

[0019] FIG. 2 is a top front left-side rear perspective view of the solar thermal window structure from building indoor.

[0020] FIG. 3 is a front view of an example solar thermal window from outdoor.

[0021] FIG. 4 is a three-dimensional section of solar thermal window structure, showing Photovoltaic cells, air channels, suspended porous metal sheets, interior and an exterior window, and air distributing panels.

[0022] FIGS. 5 and 6 are two-dimensional views of an example solar thermal window in two positions for heating and cooling. FIG.5 shows the closed valve at the entrance of the channel and open valve to outdoor to stop the process of heating and allow heated air to go outside. In this position for decreasing the temperature of Photovoltaic panels, air comes from outdoor and flows in channels and goes back to outdoor. FIG.6 shows the heating position in which at the entrance of the channel valve is open and the valves to the outside are closed. The source of air for heating in this position is from indoor through a panel below of inner window.

[0023] FIGS. 6 A, 6B, and 6C are viewing a section of a portion of the solar thermal window structure and its components, Photovoltaic cells, porous metal sheets, air channels, mainframe, window frame, window glass, interior, and exterior windows, distributing panels in below and above of the inner window, valves, and PCM sheet in back channels.

[0024] FIG. 7 is a perspective view of an example fane with a heating element for air circulating in the system placed in the above-distributing panel. [0025] FIGS. 8 A and 8B are the thermal networks of solar thermal window structure and their energy balance equations for energy performance calculation of the system. FIG. 8A is thermal network and energy balance equations of above of the system semitransparent Photovoltaic and air channels where semitransparent Photovoltaic panel is connected to outdoor directly. And FIG. 8B is for below of the system where Photovoltaic panels in between exterior and interior windows. In these thermal networks, the temperatures of elements are defined as the nodal temperature in a control volume, calculated on the base of the physical properties of system components. In other words, to determine the temperature of each element, a coupled system of equations was defined. Each control volume within the system was represented by an energy balance equation where U represents conductance between the various nodes. The resulting system of equations can be solved to find each control volume temperature.

[0026] DETAILED DESCRIPTION

[0027] In the following detailed description, numerous specific details are set forth by way of examples to provide a thorough understanding of the relevant teachings. However, it should be apparent that the present teachings may be practiced without such details. In other instances, well-known methods, procedures, components, and/or circuitry may have been described at a relatively high-level, without detail, to avoid unnecessarily obscuring aspects of the present teachings.

[0028] Disclosed is a solar thermal window structure that can form a principal chamber enclosing a building window pane installed in an exterior wall of a building. The window structure includes semitransparent Photovoltaic panels and porous metal sheets that are capable of absorbing solar energy and air channels on the back of semitransparent Photovoltaic panels where the temperature of Photovoltaic panels and porous metal sheets can be extracted through airflow. By valves on-air channels, the process of solar heating can be stopped. The Photovoltaic panels and porous metal sheets have an optimum degree to decreasing cooling demand in the hot season by making shade on the window and absorbing solar radiation, besides allowing some portion of solar radiation to reach indoor in cold seasons. As an example, this optimum degree in Toronto, Canada, besides considering the avoid of snow accumulation, is 40 degrees.

[0029] The disclosed window structure may have a simple and inexpensive structure. It may store electrical energy in storage and thermal energy in the PCM sheet and be used in cold regions or regions that have cold nights. The window structure may also be used in regions that have warm periods during which lowering the interior temperature of a building is desirable. In certain examples, during the cold seasons, after suction of the internal air of the building and warming it, this air may be filtered and returned to the internal space of the building. In warm seasons, by natural ventilation and making shade on the wall, examples of the disclosed solar thermal window structure may cool the internal air of the building.

[0030] FIG. 1 illustrates an exemplary solar thermal window structure of the instant application. The solar thermal window structure may be configured to form a main frame 13 and an exterior window ten installed on an exterior building wall 15. The above and below semitransparent Photovoltaic panels 11 act as a solar absorber for electricity and thermal generation. The above semitransparent Photovoltaic panel is connected to outdoor directly, while the below semitransparent Photovoltaic panel is placed in the enclosed place made by external window ten and internal window 17. The internal window 17 is installed on the exterior building wall. The air from panel 18 below of the internal window comes into the system, extracts the temperature of surfaces and warm-up, and after that, through distributing panel 16, goes back to the building indoor. When the heated air is not needed for building, the distributing panels 16 and 18 are closed, and air source for cooling of Photovoltaic panels is from outer panel 14. While, when the system is on solar heater position for building, the outer panel 14 is closed.

[0031] On the base of climate or region that solar thermal system installed on, the degree of semitransparent Photovoltaic panel may be different to decrease cooling demand in summer and heating demand in winter.

[0032] The semitransparent Photovoltaic includes Photovoltaic cells 11 and space between Photovoltaic cells (back sheet), which should be filled by a clear and transparent material 19, such as Polyvinyl Fluoride (PVF) back sheet.

[0033] FIG. 4 illustrates a perspective of a section of exemplary solar thermal window structure of the instant application. The enclosed space is made by main frame 13, and internal window 17, and external window 10, installed on external wall 15. The inner glass 24 and outer glass 20 of windows allow keeping view from inside to outside and reach solar radiation to indoors in winter.

[0034] In the middle of air channels in the back of semitransparent Photovoltaic panels, there is a porous metal sheet 22 absorbing the portion of solar radiation passed from semitransparent Photovoltaic panels. [0035] There may be two valves at first 25 and end 23 of the above air channel. When the valve of 25 is open, and the valve of 23 is closed, the solar thermal window system is in the solar air heater position (FIG.6). In this position, the air source for heating in the system comes from indoor through a panel 18 in the below of the inner window 17, and after raising air temperature along with the system, go back to the indoor space by a distributing panel 16. While, when raising the indoor air temperature is not desire (FIG.5), the valve of 25 is closed, and the valve of 23 is open. In this position, the air source to cooling down the semitransparent Photovoltaic panels is from outdoor through opening 14 in above of external window 10; and after extraction heat from semitransparent Photovoltaic panels, to improve electricity generation, it goes back to outdoor through opening 23.

[0036] The solar heater position (FIG.6) may be used in both cold and hot seasons. In cold seasons to cover the heating demand of buildings and in hot seasons, the heated air can be used in the HVAC system for the dehumidification process.

[0037] For storing the thermal energy generated by the air channel system, PCM sheet 21 as heat storage is embedded in the back cavity to decreasing temperature fluctuation at night or when the solar radiation is not enough.

[0038] The distributing air panel 16 includes a fan 26. The fan 26 may discharge the air heated in the interior space of the principal chamber into the interior of the building, (see FIG. 6C). In certain examples, the fan 26 may include a filter layer to filter the air in the system. The filter layer may include nano-composite membranes but is not limited thereto. The fan 26 may include a thermometer

[0039] And also, the distributing air panel 16 includes heating element 28 and electricity storage. The electricity generated by Photovoltaic cells can be stored in the storage to use whenever the solar radiation is not enough or at night to use in heating element to heat air. Or heating element may alternatively be powered by another energy source that is not necessarily included in the solar thermal window structure.

[0040] The distributing panel 16 may include a controller which can command the fan to start and stop, and valves 23 and 25 to be open or closed based on the surrounding information. The distribution panel 16 also may work manually. At certain times, for example, on hot days, ventilation may be desired. [0041] In some examples, the exterior window pane 20 may include anti-reflective glass, which may enable the energy-absorbing surfaces 11 and 22 to absorb a maximum amount of solar radiation.

[0042] To install different parts of the solar thermal window, in the first phase, a base plate that supports the overall weight of the window may be attached to the wall 15. The base plate may be made of metal but is not limited thereto, as any material strong enough to support the weight of the solar thermal window and keep it attached to the wall may be used. Also, the base plate may be attached to the wall by screws but is not limited thereto. The base plate may be installed before or after the inner window pane 17 is installed in the wall of the building. In some examples, the first window pane 17 is installed in the wall of the building prior to the forming of the solar thermal window structure. In other examples, the first window pane 17 is included in the solar thermal window structure.

[0043] Next, mainframe 13 and its structure are attached to the base plate. They may be screwed and welded to the base plate but are not limited to those forms of attachment. The interior surface of the mainframe may be black to absorb solar radiation to raise the air temperature in enclosed space. Also, the mainframe 13 may have insulation to keep enclosed air temperature warm and decrease thermal transmittance to outdoor.

[0044] Examples of the disclosed solar thermal window structure can be used as part of a building’s structure at the time of its construction, or they can be installed as an attachment to existing windows or skylights. However, in certain examples, the whole attachable solar thermal window structure 100 may be pre-fabricated and put together in the factory and afterward installed at the building site. Alternatively, the attachable solar thermal window structure may be built or put together at the building site.

[0045] By producing warm air during cold seasons of the year through using renewable solar energy, this product may help save money. It also may prevent air pollution and reduce the consumption of fossil fuels. Further, in warm seasons, by creating pleasant natural ventilation through suction and expulsion of air inside the building, it may cause a reduction in the consumption of electricity.

[0046] While the foregoing has described what are considered to be the best mode and/or other examples, it is understood that various modifications may be made therein and that the subject matter disclosed herein may be implemented in various forms and examples, and that the teachings may be applied in numerous applications, only some of which have been described herein. It is intended by the following claims to claim any and all applications, modifications, and variations that fall within the true scope of the present teachings.

[0047] Unless otherwise stated, all measurements, values, ratings, positions, magnitudes, sizes, and other specifications that are set forth in this specification, including in the claims that follow, are approximate, not exact. They are intended to have a reasonable range that is consistent with the functions to which they relate and with what is customary in the art to which they pertain.

The Abstract of the Disclosure is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the foregoing Detailed Description, it can be seen that various features are grouped together in various implementations for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed implementations require more features than are expressly recited in each claim. Rather, as the following claims reflect, the inventive subject matter lies in less than all features of a single disclosed implementation. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter.

Claims

What Is Claimed Is:

1. A solar thermal window structure configured to form a principal chamber enclosing a windowpane installed in an exterior wall of a building, the solar thermal window structure comprising:

The mainframe including a sliding window pane with its frame, tilted semitransparent Photovoltaic panels, porous surface, air channels, valves, and Phase Change Material (PCM) surface.

2. The solar thermal window structure of claim 1 , wherein the semitransparent Photovoltaic panels of at least packing factor 0.8.

3. The solar thermal window structure of claim 1, wherein the semitransparent Photovoltaic panel is black PV type with PVF back sheet.

4. The solar thermal window structure of claim 1 , wherein the two air channels are placed at the back of the semitransparent Photovoltaic panel.

5. The two air channels of claims 1 and 4, wherein a porous metal sheet between two air channels.

6. The porous metal sheet of claims 1 and 5, wherein the porous metal sheet absorbs the portion of solar radiation passed from semitransparent Photovoltaic panels.

7. The solar window structure of claim 1, wherein semitransparent Photovoltaic panels and porous metal sheet as solar absorbers and air channels are placed below and above the solar thermal window structure.

8. The solar absorber systems of claim 7, wherein the solar absorber system placed at the below of the window system is configured to warm the first air in an interior space of the principal chamber. And the solar absorber system placed at the above of the window system is configured to warm the air in the channel before going back to the building indoor space.

9. The solar thermal window structure of claim 8, further comprising a fan in a distributing panel above of inner window, configured to regulate air velocity and transmit heated air from the system to building indoor.

10. The thermal window structure of claim 1, further comprising: a fan; a heating element disposed on or near the fan, and an air filter wherein when the energy absorbed by solar absorber surfaces is not sufficient to warm air to the desired temperature, the air is warmed by the heating element, and the fan is configured to transmit the air warmed by the heating element and air filter to an interior of the building.

11. The thermal window structure of claim 1 , further comprising a Phase Change Material (PCM) sheet on the back of air channels, to increase air channel temperature in different solar radiation rates. Through the heating process in air channel, PCM panel get the latent temperature up and its phase is changed from solid to liquid, and when the solar radiation is not enough or at night, the PCM panel give temperature to the air channel as a heat transfer source and its phase come back to solid.

12. The solar thermal window structure of claim 1, further comprising inner and outer window frame. The inner window frame is installed on the exterior building wall, and the outer window frame is installed on the mainframe of the solar thermal window structure. The inner and outer windows frame provides an enclosed space to place the components of the solar thermal window structure. The inner and outer windows can be opened to make natural ventilation, and closed when the solar thermal window is in solar air heater mode.

13. The solar thermal window structure of claim 12, there are automated valves to stop the process of air heating of the solar thermal window system.

14. The solar thermal window structure of claim 13, when the solar thermal window system stops the air heating process through automated valves, the air source for flowing in air channel is from an outer opening above of the outer window frame.

15. The solar thermal window structure of claim 13, when the solar thermal window system is in solar air heater position, the air source for heating in the system comes from indoor through an opening at below of the inner window frame.

All openings in the solar thermal window system can be open and closed automatically to control the performance of the system.

16. The solar thermal window structure of claim 15, in distributing panel there is a microcontroller to control the performance of solar thermal window through changing air velocity of the fan, opening, and closing of valves and opening on the base of environmental data gathered by indoor and outdoor sensors.

17. The window structure of claim 10, wherein the distributing panel further includes an electrical energy storage element configured to supply electrical energy generated by semitransparent Photovoltaic panels to use in the heating element.

18. A method of forming a solar thermal window structure to form a principal chamber enclosing an inner window pane installed in an exterior wall of a building, the method comprising. In the first phase, a base plate that supports the overall weight of the window is attached to the exterior building wall. Next, the mainframe and its structure are attached to the base plate.