US20130008432A1

US20130008432A1 - Solar Heat Exchange Apparatus

Info

Publication number: US20130008432A1
Application number: US13/205,723
Authority: US
Inventors: Chang-Hsien TAI; Jr-Ming Miao; Geng-Ren Liu
Original assignee: Individual
Current assignee: National Pingtung University of Science and Technology
Priority date: 2011-07-04
Filing date: 2011-08-09
Publication date: 2013-01-10
Also published as: TWI431232B; TW201303235A; CN102865674A

Abstract

A solar heat exchange apparatus includes a heat holding base having a face with a plurality of heat collecting channels. Each heat collecting channel has an open end in the face of the heat holding base. A conduit extends through the heat collecting channels and is coated with a photothermal material. A plurality of light reflecting boards is mounted on the face of the heat holding base and located corresponding to the heat collecting channels and spaced from each other. Two adjacent light reflecting boards are slanted to define a light reflecting space located above and tapering towards one of the heat collecting channels. A light transmitting board is mounted on top sides of the light reflecting boards. The light transmitting board includes a plurality of light concentrating portions each of which is aligned with one of the light reflecting spaces.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to a solar heat exchange apparatus and, more particularly, to a solar heat exchange apparatus using solar energy to increase the temperature of a fluid for undergoing heat exchange.
2. Description of the Related Art
FIG. 1 shows a heat collecting device 8 for a solar water heater 9 disclosed in Taiwan Utility Model No. M370064. The solar water heater 9 includes a reservoir 91 connected to a circulating water outgoing pipe 911, a circulating water return pipe 912, a water inlet pipe 913, and a hot water output pipe 914. The heat collecting device 8 is mounted between the circulating water outgoing pipe 911 and the circulating water return pipe 912. The heat collecting device 8 includes a frame 81. A plurality of conduits 82 transversely extends in the frame 81 and is connected between the circulating water outgoing pipe 911 and the circulating water return pipe 912. Each of top and bottom faces of each conduit 82 is covered with a metal plate 821. A plurality of light concentrating lenses 83 is provided on top of the frame 81 and extends in a length direction of the conduits 82.
With reference to FIGS. 1 and 2, water in the reservoir 91 flows through the circulating water outlet pipe 911 into the conduits 82 of the heat collecting device 8. The sunlight incident on the light concentrating lenses 83 is concentrated onto the conduits 82 by the light concentrating lenses 83. The metal plates 821 covering the conduits 82 absorb the solar heat energy and transfer the solar heat energy to the conduits 82 to heat the water in the conduits 82. Thus, the water in the conduits 82 can be rapidly heated to increase the heating efficiency of the solar water heater 9.
However, although heat transfer can undergo through the metal plates 821 that cover the conduits 82 and that have a high thermal coefficient for rapidly absorbing and conducting heat, the heat loss is also considerable when a temperature difference exists between the metal plates 821 and the environment. Thus, the heat conducting efficiency is not satisfactory due to the heat loss during heat transfer between the metal plates 821 and the conduits 82, because there are no devices or media for holding the heat.
Furthermore, the sunlight is not a concentrating type light source and, thus, has scattering angles while passing through different media. The sunlight can not be completely concentrated on a specific position even though the sunlight passes through a light concentrating lens 83. Thus, a portion of the sunlight scatters after passing through the light concentrating lens 83, adversely affecting the heat collecting efficiency of the heat collecting device 8.

SUMMARY OF THE INVENTION

An objective of the present invention is to provide a solar heat exchange apparatus that can reduce the heat loss of conduits to enhance the heat conducting efficiency.
Another objective of the present invention is to provide a solar heat exchange apparatus to concentrate and project the scattered sunlight to a preset position to enhance the heat conducting efficiency.
The present invention fulfills the above objectives by providing a solar heat exchange apparatus including a heat holding base having a face and a plurality of heat collecting channels. Each of the plurality of heat collecting channels has an open end in the face of the heat holding base. A conduit extends through the plurality of heat collecting channels and is coated with a photothermal material. A plurality of light reflecting boards is mounted on the face of the heat holding base and located corresponding to the plurality of heat collecting channels and spaced from each other. Two adjacent light reflecting boards are slanted to define a light reflecting space located above and tapering towards one of the plurality of heat collecting channels. A light transmitting board is mounted on top sides of the plurality of light reflecting boards. The light transmitting board includes a plurality of light concentrating portions each of which is aligned with one of the light reflecting space.
Preferably, a pair of light reflecting boards on opposite sides of each of the plurality of heat collecting channels together defines a heat reservoir space.
Preferably, each of the heat reservoir spaces receives a greenhouse gas or a heat storage material.
Preferably, at least one leg is provided on a bottom of each of the plurality of light reflecting boards. The at least one leg extends into one of the heat reservoir spaces and is in intimate contact with the face of the heat holding base.
The present invention will become clearer in light of the following detailed description of illustrative embodiments of this invention described in connection with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The illustrative embodiments may best be described by reference to the accompanying drawings where:

FIG. 1 shows a perspective view of a conventional solar water heater.

FIG. 2 shows a cross sectional view of a portion of the solar water heater of FIG. 1.

FIG. 3 shows a perspective view of a solar heat exchange apparatus according to the present invention.

FIG. 4 shows a cross sectional view of the solar heat exchange apparatus of FIG. 3.

All figures are drawn for ease of explanation of the basic teachings of the present invention only; the extensions of the figures with respect to number, position, relationship, and dimensions of the parts to form the preferred embodiments will be explained or will be within the skill of the art after the following teachings of the present invention have been read and understood. Further, the exact dimensions and dimensional proportions to conform to specific force, weight, strength, and similar requirements will likewise be within the skill of the art after the following teachings of the present invention have been read and understood.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIG. 3, a solar heat exchange apparatus according to the present invention includes a heat holding base 1, a conduit 2, a plurality of light reflecting boards 3, and a light transmitting board 4. The conduit 2 is mounted in the heat holding base 1. The light transmitting board 4 transmits sunlight. The sunlight is reflected by the light reflecting boards 3 and concentrated on the conduit 2 to increase the temperature of the conduit 2 for undergoing heat exchange with a fluid in the conduit 2.
The heat holding base 1 includes a plurality of downwardly recessed heat collecting channels 11. Each heat collecting channel 11 has an open end in a top face of the heat holding base 1. The heat holding base 1 can receive heat energy of the sunlight and represent a high temperature state relative to the environment. Preferably, the heat holding base 1 is made of a material having a high thermal coefficient, such as solid metal. In this embodiment, the heat holding base 1 is in the form of a parallelepiped, and the heat collecting channels 11 are parallel to a side of the heat holding base 1 and located in the heat holding base 1 at regular interval to enhance installation convenience during assemblage with other members. However, the shape of the heat holding base 1 and arrangement of the heat collecting channels 11 are not limited to the form shown. The shape of the heat holding base 1 and arrangement of the heat collecting channels 11 can be varied according to the equipment cooperating with the solar heat exchange apparatus and according to need, which can be appreciated by one having ordinary skill in the art.
The conduit 2 is windingly extended through the heat collecting channels 11. The conduit 2 is coated with a photothermal material. Thus, the conduit 2 can absorb the sunlight and be heated to a high temperature state. A fluid is received in the conduit 2 for heat exchange purposes.
The light reflecting boards 3 are located on the top face of the heat holding base 1 corresponding to the heat collecting channels 11 and spaced from each other. Furthermore, two adjacent light reflecting boards 3 are slanted to define a light reflecting space 31 that is located above and tapers towards one of the heat collecting channels 11. Further, a pair of adjacent light reflecting boards 3 on opposite sides of each heat collecting channel 11 together define a heat reservoir space 32 receiving a greenhouse gas (such as nitrogen oxide) or a heat storage material. In this embodiment, at least one leg 33 is provided on a bottom of each light reflecting board 3 for reliably fixing the light reflecting board 3. The at least one leg 33 extends into a corresponding heat reservoir space 32 and is in intimate contact with the top face of the heat holding base 1 for fast assembly. Thus, each light reflecting board 3 can be retained in a fixed inclination angle without the risk of undesired displacement when the solar heat exchange apparatus is impinged, avoiding adverse affect to the light concentrating efficiency.
The light transmitting board 4 is mounted on top sides of the light reflecting boards 3 and can be made of glass or glass fiber reinforced plastic to possess high light transmittance, small thermal coefficient, and resistance to impact. Thus, the sunlight can pass through the light transmitting board 4. Furthermore, the light transmitting board 4 reduces the loss of solar heat resulting from upward heat transmission from the light transmitting board 4. Further, the light transmitting board 4 includes a plurality of light concentrating portions 41. Each light concentrating portions 41 is aligned with one of the light reflecting spaces 31. Specifically, each light concentrating portion 41 is located at an enlarged end of one of the light reflecting spaces 31. Preferably, each light concentrating portion 41 is a Fresnel lens that is light and thin and has a small focal length and allows passage of a high amount of light.
With reference to FIG. 4, by such an arrangement, a portion of the sunlight incident on the light transmitting board 4 passes through the light concentrating portions 41 and is projected onto the conduit 2 extending through the heat collecting channels 11. The temperature of the conduit 2 is increased to heat the fluid flowing in the conduit 2. Another portion of the sunlight passes through the light transmitting board 4 into the heat reservoir spaces 32.
With regard to the sunlight passing through the light concentrating portions 41, due to provision of the light reflecting boards 3, the scattered light beams can be reflected in each light reflecting space 31 so as to concentrate and project the light beams onto the conduit 2, enhancing the light concentrating effect of the conduit 2 and rapidly collecting the heat and increasing the temperature.
With regard to the sunlight entering the heat reservoir spaces 32, the greenhouse gas or the heat storage material in each heat reservoir space 32 absorbs the sunlight and generates heat energy to increase the temperature in each heat reservoir space 32, and the heat energy is transferred downward to the heat holding base 1 to increase the temperature of the heat holding base 1 to a high temperature state. By such an arrangement, each heat collecting channel 11 of the heat holding base 1 is maintained at a high temperature to reduce the temperature difference between the conduit 2 and the environment (i.e., each heat collecting channel 11), reducing the heat loss of the conduit 2 and easily maintaining the conduit 2 in the high temperature state.
In view of the foregoing, the solar heat exchange apparatus according to the present invention can minimize the heat loss of the conduit 2 by providing the heat reservoir spaces 32 and by locating the conduit 2 in the heat holding base 1 capable of holding heat. A large amount of heat energy can be provided to the fluid in the conduit 2 for heat exchange purposes, enhancing the heat conducting efficiency and gradually increasing the temperature of the fluid while flowing in the conduit 2.
In the solar heat exchange apparatus according to the present invention, the light concentrating effect of the conduit 2 is enhanced by providing the light reflecting boards 3 to concentrate and project the scattered sunlight onto the conduit 2, so that the temperature of the conduit 2 can be rapidly increased, providing enhanced heat collecting efficiency.
Thus since the invention disclosed herein may be embodied in other specific forms without departing from the spirit or general characteristics thereof, some of which forms have been indicated, the embodiments described herein are to be considered in all respects illustrative and not restrictive. The scope of the invention is to be indicated by the appended claims, rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Claims

1. A solar heat exchange apparatus comprising:

a heat holding base including a face and a plurality of heat collecting channels, with each of the plurality of heat collecting channels having an open end in the face of the heat holding base;

a conduit extending through the plurality of heat collecting channels and coated with a photothermal material;

a plurality of light reflecting boards mounted on the face of the heat holding base and located corresponding to the plurality of heat collecting channels, with the plurality of light reflecting boards spaced from each other, with two adjacent light reflecting boards being slanted to define a light reflecting space located above and tapering towards one of the plurality of heat collecting channels; and

a light transmitting board mounted on top sides of the plurality of light reflecting boards, with the light transmitting board including a plurality of light concentrating portions, with each of the plurality of light concentrating portions aligned with one of the light reflecting space.

2. The solar heat exchange apparatus as claimed in claim 1, with a pair of light reflecting boards on opposite sides of each of the plurality of heat collecting channels together defining a heat reservoir space.

3. The solar heat exchange apparatus as claimed in claim 2, with each of the heat reservoir spaces receiving a greenhouse gas or a heat storage material.

4. The solar heat exchange apparatus as claimed in claim 2, with at least one leg provided on a bottom of each of the plurality of light reflecting boards, with said at least one leg extending into one of the heat reservoir spaces and in intimate contact with the face of the heat holding base.

5. The solar heat exchange apparatus as claimed in claim 3, with at least one leg provided on a bottom of each of the plurality of light reflecting boards, with said at least one leg extending into one of the heat reservoir spaces and in intimate contact with the face of the heat holding base.