DESC:FIELD OF INVENTION:
The present invention relates to renewable energy systems, especially a solar-powered heat exchanger system designed to efficiently capture solar energy for various heating applications.
BACKGROUND OF THE INVENTION:
With increase in demand of energy resources, there is much of an emphasis on usage of renewable energy sources to mitigate climate change and counteract the depletion of fossil fuels. Solar energy, in particular, has attracted much attention due to its abundance and sustainability. Various solar thermal systems have been developed to utilize solar energy for heating purposes. Heat exchangers play a crucial role in efficiently transferring thermal energy from a solar collector to a working fluid, which can then be used for space heating, water heating and industrial processes.
Conventional air heating systems often rely on fossil fuels or electrical energy, leading to high operating costs and environmental pollution. In remote or high-altitude regions, accessing these energy sources can be logistically challenging and expensive.
Solar thermal systems usually consist of solar collectors, a working fluid circuit, and a heat exchanger. Solar collectors, often flat plate or concentrating collectors, absorb solar radiation and heat a circulating working fluid. This heated fluid is then passed into a heat exchanger where it transfers its thermal energy to another fluid, usually water or air, for the intended heating application. Although these systems are effective to some degree, they have several shortcomings. A similar approach has been identified in CN102230677, which discloses a flat plate solar air heater which contains a transparent solar absorber, vertical fins arranged in staggered manner to distribute air evenly, a shell with insulator, header at each end of the heat exchange plate.
A major limitation of conventional solar thermal systems is that they rely on additional heating sources (such as electric or gas heaters) during periods of insufficient solar radiation (on cloudy days or at night). This dependence on non-renewable energy sources reduces the overall sustainability and cost-effectiveness of these systems. Similar invention has been proposed in US2010/0072292 A1.
Immobility and complexity of the existing solar heat exchanger system is another drawback, which limit the application of these systems to fixed location and reduces its adaptability.
US2012/0175082 A1 discloses the best mode of collecting heat and extracting it from a heat pipe for solar energy applications is the subject of this invention. The system can operate in a variety of operational designs, including integrated solar thermal and photovoltaic array configurations, solar vacuum tubes, and solar collector panels. A heat pipe receiver, which encloses the condenser end of the heat pipe and plugs into the interior of the header assembly, connects the header assembly structurally and thermally to the heat pipe.
Furthermore, the existing solar thermal systems frequently fail to attain high thermal efficiency, resulting in poor energy conversion rates and slower heating rates. This restriction is due to inefficiencies in the heat exchangers utilized in these systems, which fail to capture and transmit available solar energy.
Therefore, there is an urgent need of a reliable and cost-effective solar powered heating system and which addresses the problems in the existing air heating solutions.
OBJECT OF THE INVENTION:
It is an object of the present invention to provide for a solar powered oil heat exchanger.
It is another object of the present invention to provide for a reliable air heating device to heat air specially in temperate zone.
It is yet another object of the present invention to provide for a air heating device which is fully portable and can be easily installed in high altitude terrain.
It is yet another object of the present invention to provide for stable and continuous heating of air, can be achieved due to inbuilt high heat storing capacity of the heating fluid which incorporates the solar radiation fluctuations.
It is yet another object of the present invention to provide for a uniquely designed oil heat exchanger (1) consisting of the specially designed heating tube (12, 13) attached with the fins (11).

SUMMARY:
In an embodiment, the present invention discloses a heat exchanger (1), comprising an air inlet (5), an air outlet (6), a solar collector unit (3) and a heat exchange unit (2).
In this embodiment, the heat exchange unit (2) comprises of a first chamber (7), a second chamber (8) and heating components, whereby air passing through the inlet (5) is heated by the heat exchange unit (2) and exits through the outlet (6).
In a preferred embodiment, the solar energy collector unit (3) is an arrangement of Evacuated Tube Collectors.
In a preferred embodiment, the heating components comprises of tubes (12, 13) and fins (11), wherein the tubes (12, 13) may be in a shape selected from rectangle and triangle, and wherein the fins (11) are rectangular.
In a preferred embodiment, the second chamber (8) is a storage chamber to a heating medium such as oil and wherein the first chamber (7) is a cold air chamber.
In this embodiment, the solar collector unit (3) is configured to capture solar radiation and convert it to thermal energy. There is provided a heat transfer fluid circulation means configured to transfer the thermal energy from the solar collector unit (3) to the heat exchanger unit (2) through the connection passage (9). The transferred thermal energy is then used to heat the incoming air from the inlet (5) and causes exit of hot air through the outlet (6).
BRIEF DESCRIPTION OF THE DRAWINGS:
The present invention will be described in more detail hereinafter with the aid of the accompanying drawings. The drawings are illustrative of one or more embodiments of the invention and do not in any manner limit the scope.
Figure 1 illustrates a perspective view of the heat exchanger according to the present invention.
Figure 2 illustrates the internal components of heat exchange unit.
Figure 3 illustrates enlarged view of the internal components shown in Figure 2.
Figure 4 illustrates the internal components of the solar collector unit.
DESCRIPTION OF THE INVENTION:
The following description illustrates various embodiments of the present invention and ways of implementation. The embodiments described herein are not intended to be limited to the disclosure and that the same is in no way a limitation. The invention may be embodied in different forms without departing from the scope and spirit of the disclosure.
The illustrations are not intended to serve as a complete description of all of the elements and features of apparatus and systems that utilize the structures or methods described herein. Many other embodiments may be apparent to those of skill in the art upon reviewing the disclosure. Other embodiments may be utilized and derived from the disclosure, such that structural and logical substitutions and changes may be made without departing from the scope of the disclosure.
Additionally, the illustrations are merely representational and may not be drawn to scale. Certain proportions within the illustrations may be exaggerated, while other proportions may be minimized. Accordingly, the disclosure and the figures are to be regarded as illustrative rather than restrictive.
Specific dimensions and/or other physical characteristics relating to the embodiments disclosed herein are therefore not to be considered as limiting unless the claims expressly state otherwise.
Further, reference numerals are used only as an aid to explain the invention and they do not in any matter restrict the scope of the invention.
The present invention seeks to overcome the drawbacks existing in the priori arts by providing for a solar-powered heat exchanger and a method of heat exchange, that maximizes the use of solar energy for heating applications, while reducing or eliminating the requirement for auxiliary heating sources. The present invention addresses the need for sustainable and cost-effective heating solutions, particularly in remote or high-altitude regions where traditional energy sources are inaccessible or impractical.
Generally referring to figures 1-4, the present invention discloses a Solar-Powered Oil Heat Exchanger, as a renewable energy device designed for efficient air heating applications. It utilizes a solar collecting unit to capture solar radiation and heat a high-capacity thermal fluid, typically oil, up to 120°C. The heated oil naturally circulates into the heat exchanger through convection, eliminating the need for mechanical pumps, ensuring energy efficiency, and minimizing maintenance.
The present invention, in a preferred embodiment, discloses a combination of triangular and rectangular heating tubes coupled with rectangular fins. This configuration enhances heat transfer by maximizing turbulence and surface area. The triangular tubes improve convective heat transfer, while the rectangular fins and tubes ensure rapid and uniform heating through conduction. An integrated hot fluid chamber stabilizes performance, providing consistent heat output even during fluctuations in solar radiation.
The Heat Exchanger operates through integration of evacuated tubes with heat pipes, a hot fluid chamber, and a heat exchanger unit. This system efficiently converts solar energy into thermal energy, which is then transferred to air for heating applications. Its design prioritizes high efficiency, portability, and adaptability, making it suitable for diverse applications such as residential heating, industrial processes, and use in high-altitude or remote regions.
The solar-powered heat exchanger (1), according to the present invention, comprises of a solar collector unit (3) configured to capture solar radiation and convert it to thermal energy. There is provided a heat transfer fluid circulation means configured to transfer the thermal energy from the solar collector unit (3) to the heat exchanger unit (2) through the connection passage (9). The transferred thermal energy is then used to heat the incoming air from the inlet (5) and causes exit of hot air through the outlet (6).
The present invention, in an exemplary embodiment, provides a heat exchanger (1) with an oil heat exchange unit (2) integrated with ETC Tubes (3) that receives direct solar radiation from the sunlight.
In a preferred embodiment, the solar collector unit (3) is an Evacuating solar collector tube (ETC) where the solar radiation is captured and used for heating a fluid medium, such as oil, and convert it to thermal energy.
The ETC tubes (3) are very much efficient in observing the solar radiation and stores the thermal energy by increasing the internal energy of fluid. The ETC tubes (3) are directly attached to the heat exchange unit (2) for continuous and effective transportation of thermal energy through the oil circulation from ETC tube (3) to the specially designed heat exchange unit (2).
The heat exchanger unit (2) includes heat exchange surfaces/components (11, 12, 13) for transferring thermal energy from the heat transfer from the heating fluid medium (Oil) to a secondary medium (air).
In an embodiment, a control and monitoring system may be employed to optimize the operation of the solar collector unit, the heat transfer fluid circulation system, and the heat exchanger unit.
The present invention is also devoid of any kind of mating element and hence, does not produce any noise during operations.
Referring to Figure 1, it discloses a solar powered heat exchanger (1) according to the present invention. There is disclosed a heat exchange unit (2), a solar collector unit (3), support stand (4), air inlet (5) and air outlet (6).
Heat exchange unit
Referring to Figure 2, it discloses internal parts of the heat exchange unit (2), where transfer of thermal energy stored in a heat transfer medium to atmospheric air occurs. The unit (2) comprises a first chamber (7) which is a cold air chamber and acts as a passage for the atmospheric air. There is provided a second/hot fluid chamber (8), which hold the heat transfer medium.
In a preferred embodiment, the heat transfer medium is oil.
Preferably, the oil is a high-capacity thermal fluid, with a heating capacity up to 120°C.
The unit (2) further comprises heating components/heating means in the form of heating tubes and fins. These components are designed to maximize heat transfer efficiency through conduction and convection.
A first set of tubes/first tubes (12) are strategically placed to induce turbulence in the airflow, enhancing convective heat transfer. The turbulence ensures that the air passing through the heat exchanger absorbs heat more efficiently. Preferably, the first tubes (12) are triangular in shape.
A second set of tubes/second tubes (13) provide a large surface area for heat conduction. These tubes (13) are placed in a diagonal configuration to the triangular tubes (12). Preferably, the second tubes (13) are rectangular in shape.
A set of fins (11) are attached to the second tubes (13), whereby the fins (11) significantly increase the surface area available for heat transfer. As air flows over the fins (11), it absorbs heat, resulting in a rapid and uniform temperature increase. Preferably, the fins (11) are rectangular in shape.
Heat is transferred from the oil flowing inside these tubes (12, 13) to the rectangular fins (11).
The heat pipes efficiently transfer heat from the evacuated tubes (3) to the oil in the hot fluid chamber (8), ensuring rapid and consistent thermal energy transfer.
The first chamber (7) is configured to receive cold air in order to heat it, wherein heat is received from the heated fins (11) and the heating tubes (12, 13).
The heated oil from the hot fluid chamber enters the triangular and rectangular tubes within the heat exchanger. As the air passes through the fins, it absorbs heat and exits the system at a significantly higher temperature.
The present invention discloses a uniquely designed rectangular fin (11) which increases the surface area and provides efficient heating with this heat exchanger (1).
The present invention adapts a unique design with triangular (12) and rectangular (13) heating tube. A plurality of rectangular fins (11) arranged in symmetric pattern are attached with the rectangular (13) and triangular (12) tubes from the two ends. The fins (11) make passage for the air and transfer heat to the air. The arrangement in a unique pattern increases the effectiveness of the heat exchanger. When the cold fluid enters (5) the heat exchanger it comes into contact with these unique patterns of heating tubes (12, 13) and fins (11). Since these heating tubes are made of high thermal conductive materials, they start transferring heat to the cold fluid through the conduction process. The rectangular (13) and triangular (12) combination of the heating tubes changes the flow behaviour of the cold fluid and increases the turbulence which increases the rapid heating through the conduction and convection process. Further the air passes through the rectangular fins (11) have large surface area in contact with cold fluid, whereby heat is transferred to the cold fluid. By the time cold fluid leave the heat exchanger through outlet it gains the significant amount of heat and temperature rises up to 90o Celsius. The hot fluid from the exit of heat exchanger can be utilized in various domestic and industrial applications.
The rectangular fins (11) are maintained at base temperature at both end and the temperature gradient (dT/dx=0) becomes zero at the centre length of fin. Henc the proposed fin can be assumed as a fin with finite length and insulated at the centre. The rate of heat transfer (Q), effectiveness (e) and efficiency (?) of the proposed fin can be calculated using the following equations:
Q=v((hpk) )*tanh?(ml) (1)
e=(Heat transfer with fin)/(Heat transfer without fin)=v((hpkA_cs ) )*(T_b-T_a )*tanh?(ml) (2)
?=(Actual heat transfer from the fin surface)/(Ideal heat transfer from the fin surface)=((tanh(ml))/ml) (3)
Where, h is the convective heat transfer coefficient of the cold fluid, p is the perimeter of the rectangular fin, k is the thermal conductivity of the fin material, A_cs is the cross-section area of the fin, l is the length of the fin, m is the constant given as v(hp/(kA_cs )).
The analytical observation from the equations (1) to (3) show that the heat transfer rate from the proposed invention has increased significantly since both end of the rectangular fins (11) is maintained at high temperature. The high temperature of the fin at both ends, increases the heat transfer rate to the cold fluid results in increased thermal efficiency of the heat exchanger (2).
The present invention is fabricated using the highly conductive material such as copper, aluminium etc. to balance the effectiveness and cost of the device. The heat exchanger Tubes (12,13) are made of copper while the ETC tube setup (3) are made of glass tube. To minimize the overall cost of the present invention, the oil heat exchanger may be encased by an upper and lower covers (14,15) with mild steel that may reduce the heat loss to the surrounding and provides more compact setup.
Referring to Figure 3, it discloses an enlarged view of the internal components of the heat exchange unit (2). The second chamber (8) comprises of a plurality of cavities (10) for storing hot oils/heated oils and further comprises a plurality of connection passages or connection points (9) for the ETC tube in order to create a passage for hot oil circulation. The connection passages or connection points (9) permits flow of hot oil into the second chamber (8) and also provides for robust attachment of solar collector unit (3) to the unit (2).
The cavities (10) within the chamber (8) are critical components that act as both a thermal reservoir and a stabilizer. Made from insulated mild steel, the cavity (10) stores the heated oil, maintaining consistent thermal performance.
Solar collector unit
The internal components of the solar collector unit (3) are described via Figure 4. The solar collector unit (3) is an evacuated tubes arrangement, each equipped with an internal heat pipe (16).
In the present invention, the evacuated tubes (3) are double-layered glass cylinders with a vacuum layer between the inner and outer glass. This vacuum acts as an insulator, significantly minimizing thermal losses. The inner surface of the tubes is coated with a selective material that maximizes solar radiation absorption.
The heat pipes (16) in the evacuated tubes (3) are sealed copper tubes containing an anti-freezing working fluid, such as alcohol, distilled water, or copper oxide-enhanced fluids, under vacuum. The lower section, in contact with a solar-heated absorber plate (18), transfers heat to the working fluid inside the heat pipe (16), causing it to evaporate.
The evaporated working fluid rises to a condenser section (17) of the heat pipe (16), located at the upper end of the evacuated tube (3).
The cavity (10) of the unit (2) is connected directly to the condenser sections (17) of the heat pipes (16). The condenser section (17) is immersed in the oil within the hot fluid chamber (8), where it releases its latent heat to the oil. The working fluid in the heat pipe (16) then condenses and returns to the lower section of the heat pipe (16) via gravity, completing a continuous thermal cycle. This cycle ensures efficient heat transfer, minimizes loss, and enables reliable operation in extreme temperatures.
The heated oil stored in the cavity (10) flows into the heat exchanger unit (2), where it transfers thermal energy to the atmospheric air entering the first chamber (7) via the inlet (5). The cavity (10) also ensures that any fluctuations in solar radiation, such as cloudy conditions, do not affect the heat exchanger’s performance. During these periods, the stored thermal energy in the cavity (10) compensates for the reduced solar input.
The cavity (10) forms the connection point between the evacuated tubes (3) and the heat exchanger unit (2). Cooler oil from the heat exchanger unit (2) returns to the hot fluid chamber (8), where it is reheated by the heat pipes. This continuous loop is powered by natural convection, eliminating the need for mechanical pumps.
The ETC tubes (3) are the most efficient type of solar radiation collector. It is basically a glass tube encircled by another concentric glass tube, maintaining the vacuum in between them. The inner tube is covered with selective coating to minimize the emission. The inner tube contains oil or any fluid having high heat storing capacity, gets heated by the solar radiation up to 90o -120o Celsius. During the heating process the density of the fluid decreases and flow upward towards the oil storage cavity (10) whereas the cold fluid of higher density flows down to the ETC tube (3). This thermal movement is a continuous cycle during the entire heating and cooling process. Since the Oil storage cavity (10) continuously gets heated with large quantity of thermal energy by the solar radiation, it provides the constant heating of the cold air without getting affected by the fluctuations in solar radiation.
The present invention discloses an oil heat exchanger (1) consisting of the specially designed heating tube (12, 13) attached with the fins (11). The hot fluid is continuously circulating by natural convection laws from the ETC tube (3) into the hot fluid chamber (10) through the connection passages (9). Also, the hot oil circulates from the hot fluid chamber (10) to the tubes (12, 13). These rectangular (13) and triangular (12) heating tubes are arranged in such a way that each base of the rectangular fin (11) are in direct contact. The tubes (12, 13) are made of highly conductive material attached with hot chamber (10) at the base and with fins from two sides. It is maintained at high temperature to transfer the majority of heat to fins through conduction.
The present invention ensures steady heating even with the fluctuated solar radiation since it has inbuilt hot fluid cavity (10).
The method of operation is a closed-loop configuration powered by natural convection. As described via Figure 1, Solar energy is absorbed by the evacuated tubes (3), where the heat pipe (16) observes the heat and transfer the energy to the oil in the hot fluid chamber (8) through the condenser (17). The heated oil transfers heat to the heat conducting fins (11,12 and 13), where it transfers thermal energy to the air entering through the inlet (5). The heated air flows out of the heat exchanger through the outlet (6). The hot oil continuously recirculating through natural convection and receiving the heat through the condenser in the hot fluid chamber (8), completing the cycle. The absence of mechanical pumps ensures low maintenance and energy-efficient operation. The lightweight, solid structure (4) provides rigid support for the entire system, ensuring stability and durability under various operating conditions.
In order to establish the efficiency of the heat exchanger, certain experimental observations were obtained, which are tabulated as Table 1 hereinbelow.
Condition Solar Radiation (W/m²) Ambient Temp (°C) Oil Temp (°C) Air Temp Increase (°C)
Sunny Winter Morning 845 12 98 62
Clear Afternoon 902 16 102 58
Early Spring Day 870 19 105 52
Cloudy Winter Day 420 9 83 38
The experimental conditions were observed in four states, such as sunny days, clear sky day, in spring and winter. The variation in the experimental conditions would demonstrate the ability of the heat exchanger to perform at differing conditions.
Experimental data shows that under sunny winter conditions with solar radiation of 845 W/m², the heat exchanger achieved an air temperature increase of 62°C and maintained an efficiency of 76%.
Experimental data indicates that under clear sky conditions with solar radiation of 902 W/m², the heat pipes within the evacuated tubes elevated the oil temperature in the hot fluid chamber to 102°C. This configuration eliminates heat loss and ensures stable performance even in fluctuating environmental conditions.
On an experimental condition of a cloudy winter day with solar radiation of 420 W/m², the hot fluid chamber maintained the oil temperature at 83°C, enabling an air temperature increase of 38°C.
The tabular data validates the ability of the heat exchanger (1) to maintain stable performance under diverse conditions. The oil temperature in the hot fluid chamber and the air temperature increase observed demonstrate the heat exchanger’s high thermal efficiency and adaptability.
The present invention promotes low operation cost, as the heat exchanger is integrated with ETC tubes to utilize the solar thermal energy and thereby, eliminating running cost.
Further, the heat exchanger of the present invention has increased mobility, i.e., it is fully portability, enabling it to be used at remote locations, especially at high altitudes region.
In this present invention of heat exchanger, two different specially designed tube has been used one is triangular (12) and the other one is rectangular (13) type of tube. This specially designed tube is arranged in such a manner that the entire external flow volume is evenly covered and directs air to flow through fins (11). The combination of rectangular and triangular heat tube accelerates the fluid flow in turbulent manner which increases the rate of heat transfer and these tubes also transfer the heat to the fluid through the conduction.
Furthermore, to increase the heat transfer rate the volume to surface area is increased by integrating the rectangular fins (11) arranged horizontally.
The oil heat exchanger (1) according to the present invention provides constantly the heated air which can be used to maintain the temperature of the confined space specially in the high-altitude region where the temperature is not adequate for human habitability.
The present invention can be fabricated by a combination of various manufacturing technique such as forming, followed by machining, welding, and surface finishing process.
Further advantage of present invention is that it can heat air continuously up to 900 Celsius which allows to maintain the temperature in habitable range of a confined space in cold region/high altitude even in a cloudy day.
Another advantage is that the cold fluid flow rate can be controlled. Further, it also serves as air heater using the renewable source of solar energy to heat the hot fluid (Oil) and do not produce environmental pollution.
The above-mentioned description illustrates and depicts various embodiments of the present invention. However, it will be appreciated that numerous changes and modifications are likely to occur as per user requirements, and it is intended in the appended claims to cover all these changes and modifications which fall within the true spirit and scope of the present invention.
,CLAIMS:WE CLAIM:

1. A heat exchanger (1), comprising:
An air inlet (5);
An air outlet (6);
solar collector unit (3);
a heat exchange unit (2), comprising:
a first chamber (7); and
a second chamber (8);
wherein the heat exchange unit (2) further comprises of heating components; and
wherein the air passing through the inlet (5) is heated by the heat exchange unit (2) and exits through the outlet (6).

2. The heat exchanger as claimed in claim 1, wherein the solar energy collector unit (3) is an arrangement of Evacuated Tube Collectors.

3. The heat exchanger as claimed in claim 1, wherein the heating components comprises of tubes (12, 13) and fins (11).

4. The heat exchanger as claimed in claim 1, wherein the tubes (12, 13) may be in a shape selected from rectangle and triangle.

5. The heat exchanger as claimed in claim 1, wherein the fins (11) are rectangular.

6. The heat exchanger as claimed in claim 1, wherein the second chamber (8) is a storage chamber; and wherein the chamber (8) is configured to storage a heating medium.

7. The heat exchanger as claimed in claim 1, wherein the first chamber (7) is a cold air chamber.

8. The heat exchanger as claimed in claim 1, wherein the second chamber (8) comprises of a cavity (10) to hold the hot oil.

9. The heat exchanger as claimed in claim 1, wherein the ETC tubes (3) are connected to a plurality of connection passage (9) in the unit (2).

10. The heat exchanger as claimed in claims 1 and 6, wherein the heating medium is oil.