JPS60235957A - Fiber reinforced concrete solar collector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The invention relates to a solar collector made using fiber reinforced concrete.

The rapidly increasing cost of conventional forms of energy, largely due to the increasing cost of the fuels that provide conventional energy, has drawn attention to the need for solar energy source development. The environmental impact of fossil fuel use for energy provision is further impetus for the development of such alternative solar energy.

Efficient and economical collection of solar radiation should be the preferred means for heating and cooling buildings, domestic hot water heating, and industrial heating.

However, while much research is being done on the feasibility of using flat solar collectors, including the physics of high-absorption, low-remission (radiation)-opposed surfaces, the success or failure of the commercialization of solar thermal energy will depend on the availability of conventional fuels. depend largely on the development of systems that provide energy at a cost low enough to compete with that of other countries.

This requires more than the development of highly selective surfaces capable of providing sufficient heat absorption over the average period of clear and cloudy days. The economic viability of such systems is due to the fact that solar energy harvesting panels are relatively inexpensive, lightweight, and
And it needs to be of durable construction. Among the durability properties must be both balance of thermal expansion coefficient and strength over the wide range of temperatures typically experienced in solar energy harvesting. Such a lack of strength and thermal balance will result in panels with short lifetimes; this more than erases any positive effects from the use of lower cost materials.

It is known to construct solar collectors using Funkrete materials. Alosl U.S. Patent No. t,
No. 1611.9 3 3 describes a precast concrete solar panel having channels in the concrete that serve as conduits for carrying the fluid that performs the heat transfer intermediate close to the flat surface of the panel.

Although such a panel will provide durability, it will not be lightweight. Additionally, heat transfer through the concrete to the walkway surface may be inefficient.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a solar lifter characterized by a low cost, lightweight, efficient and durable construction. Another object of the invention is to provide a solar collector that utilizes materials having substantially balanced coefficients of thermal expansion. Yet another object of the invention is to provide a lightweight solar collector made using fiber reinforced concrete. These and other objects of the invention will become apparent from the following description and drawings.

DESCRIPTION OF THE INVENTION In FIG. 1, the solar collector of the present invention is indicated generally at 2. The solar-6 tank 2 includes a molded nozzle 10 of glass-reinforced concrete, in a preferred embodiment having a lightweight cellular concrete layer 20 bonded to one side thereof. As described in more detail with respect to FIG. 2, the concrete panel 10 is conveniently formed by application to a mold with uncured comfleet shredded fibers. Lightweight cellular concrete insulation is then applied to the exposed surfaces of the concrete panels. Panel 10 is formed as a corrugated panel with grooves /2 and flat raised lands /4'. After hardening of the concrete groove 10, the glass plate 30 is bonded to the flat land/l on the panel IO, thereby cooperating with the groove 12 between the panel IO and the glass plate 3.
A passageway 15 is defined between the two.

The glass plate 30 is attached to the panel 10 by, for example, 5 aureisin.
Cement binder like cement bond or Amer
ican Chemical Gompan'/r
I/Encina Avenue, Pa1o Al
bonded with a suitable bonding agent IIO, such as an epoxy resin such as the epoxy adhesive Aquatapoxy available from Co., Ltd., OA 91130/. The bonding agent is applied to the flat lands/l of the panel 10 and the glass plate 30 is then pressed firmly onto the flat painted lands.

Cover with selective solar coating to minimize radiation.

Although several different coating materials are known that can be applied to glass surfaces to provide selective solar coating, FIG. 2 includes a layer 37 of silicon nitride applied directly to the surface of glass plate 30. 3 shows a preferred composite footing. A layer 32 of metallic molybdenum is applied as a reflection to the silicon nitride layer 37. A chromium oxide barrier layer 33 is then applied to the molybdenum layer 32. Next, a layer 3t of amorphous metal silicon
is applied as an absorbent layer. Finally, the second layer of silicon nitride 3! is applied as an antireflection layer. Other coatings applied as paints are commercially available.

Referring again to FIG. 1, the concrete panel 20 has a raised peripheral lip defining a first portion perpendicular to the flat land /l, a second shoulder portion /7, and a third shoulder portion /7.
upright portion/g. A protective glass layer or plate SO is mounted on the shoulder/7 of the panel 10 using a suitable gasket-like sealant, such as a silicone rubber sealant.

A glass layer 50, which may be composed of hardened glass for strength purposes if necessary, acts as a protective member for the coating surface of the glass plate 30. In addition, glass plate, glass plate, 5'O
and the volume defined by the upright portions of the panel 10 allows radiation to easily pass through while the glass plate 3
an insulating insulation gap 7 providing a thermal conduction block that stores heat from radiation absorbed on the selective coating on the
Provides 0.

In the illustrated embodiment, the rolled steel clip 0 is connected to the panel IO
By biting the periphery of the lower surface of the upper shoulder/7 and the upper surface of the glass plate 50, the glass plate S is removed in such a way that it can be easily removed and replaced if the plate SO is later damaged during use.
Hold the O firmly to the solar collector assembly A2.

Now, referring more specifically to FIG.
is formed by applying a thin layer of cement to mold 100. In a preferred embodiment, the concrete along with the reinforcing fibers is applied to the mold by a gun such as that used for in-situ forming of concrete swimming pools. The mold 100 is
It is male with raised portions 102 that correspond to the corrugated grooves 72 to be formed in the panel 10. The lowered area of the flat bottom/10 is the raised flat land of the panel 10/
form l. //, 2 is the finish trim line.

The concrete used to form the panel 10 is A
Portland cement such as STM Type I or I or Type ■. Preferably the Portland cement is of the low alkali type.

The concrete is reinforced with shredded edges i that can withstand alkaline attack from the concrete.

In a preferred embodiment, the fiber is “Gem-FIL”
Glass fibers made from zirconia sand, such as those sold under the trademark "AR". Preferably the glass fibers are applied at the same time as the concrete is applied to the mold.
/2" lengths. This is conventionally designed to mix with concrete in a gun used to cut the glass fibers and apply their mixture with concrete to the mold. Preferably, the resulting glass fiber reinforced concrete is then applied to the mold in a layer about 3/16" thick.

After applying the glass-reinforced concrete 5+11) to the mold 100, the mold 100 is still facing horizontally (the glass-reinforced concrete faces upward), and the mold side pieces /20 are placed around the mold 100. is placed in In a preferred embodiment,
Next, a layer of lightweight aerated concrete! 0 is poured onto the glass reinforced concrete to an average depth of about 2 inches to provide insulation on the back of the panel. The glass reinforced concrete and the lightweight foam concrete applied thereon are then cured together to form a strongly bonded structure.

Lightweight cellular concrete is preferably lightweight concrete formed using a foaming agent to produce cellular concrete. In a preferred embodiment, Neopor V
Neo from erfahrenstecnik GmbH
Biodegradable blowing agents containing hydrolyzed proteins, such as those sold under the trademark POR, are used. A foaming agent is a foaming agent/
It is mixed with water at a ratio of 10 parts water per part and mixed together to form an emulsion that is pressurized and released as a foam having the consistency of shaving cream. This phono emulsion is then mixed with sand, portland cement and water. The ratio can vary considerably depending on the desired strength. Lightweight materials with high insulation values and densities of about 3 g bond per cubic foot include sand 33 Il bond, Portland cement 523 bond, and water/13 bond, ? , 311
mosquito.

mix with

The use of other lightweight concretes with foaming agents or lightweight aggregates is within the contemplation of the present invention and is intended to be encompassed by the term "lightweight cellular concrete" as used herein.

After the lightweight cellular concrete and glass-reinforced molded concrete harden, the mold is removed and glass plate bonding agent is applied to the flat lands of the glass-reinforced concrete.

The coated glass plate 30 is then pressed firmly in place to cure the bonding material.

In the embodiment illustrated in FIG. 1, the glass reinforced concrete panel 10 and the glass layer 30 thereon form a long winding groove/S.

It will, of course, be understood that various shapes of passageways may be formed. However, the passages are shallow so as to provide maximum surface area in contact with the glass layer with the selective coating and allow maximum heat transfer from the radiation absorbed by the glass to the liquid flowing through the passages. It is also preferably wide. In accordance with the present invention, the panel IO provides manifolds at opposite ends of the collector having generally parallel passageways interconnecting the opposing manifolds to provide parallel liquid flow from one manifold to the other. It can be shaped like this. Alternatively, the passageway may be formed as a continuous winding passageway having seven entrances and one exit.

However, in any aspect, it should be noted that the invention is characterized by the use of materials having substantially the same coefficient of thermal expansion. That is, the concrete casting board, the fiber reinforcement therein, the foam concrete insulation bonded thereto, the glass with the selective solar coating, and the protective glass layer all have substantially the same coefficient of expansion and thus the solar Due to the low ridge temperatures (winter nights) that can be found in the collectors to the boiling point of the liquid used - this allows the use of the panels through a temperature range that can be as high as □, which can be as high as 200°C. do. Furthermore, the second part of the panel is heated substantially above this temperature by 300°.
It can rise to a height of C. Although the panel illustrated in Figure 1 includes steel clips to hold the upper protective glass layer, the nature of this type of construction, which uses flexible spring steel clips, is such that the thermal stability of this component It will be readily apparent that misbalances can be tolerated without detracting from the desired objective of a thermally unbalanced composite panel.

In other words, the use of spring clips would otherwise shorten the life of the panel and thus defeat the purpose of the present invention, which is to provide a low cost yet durable solar collector. No breakage or leakage of bonds between wax components. In this regard, it should be noted that the spring clips can be replaced with a bonding material similar to that used to hold glass pane 30 to panel-10, if desired.

The invention has been described in terms of its preferred embodiments.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway isometric view of the solar collector of the present invention, FIG. 2 is a sectional view illustrating the structure of the solar collector of the present invention, and FIG. 3 is a fragmentary sectional view of selective coating. 10...Glass reinforced concrete panel, /2.
...Groove, /lI...Land, /Yu, Instep, Passage, 20...Lightweight aerated concrete, 30.3.・
・Glass plate, SO... Protective glass plate.

Claims (9)

[Claims] (1) a glass member having a selective solar coating on a first gable surface characterized by high absorption and low radiation; The concrete member comprises thin-walled concrete reinforced with alkali-resistant fibers and cooperates with said glass member fixed thereto to provide a series of passageways through which a heat exchange fluid can be conveyed to the heat exchanger. A solar collector that is a shaped member, further characterized by the use of a material having a coefficient of thermal expansion that is substantially balanced over the temperature range to which the solar collector is normally exposed. (2) The collector according to claim 1, wherein the alkali-resistant fibers are made of alkali-resistant glass fibers. (3) The collector of claim 2, wherein the alkali-resistant glass fibers are made from Zilphnia glass. (4) The alkali-resistant glass fiber is about / to 77
3. The collector of claim 2 which is chopped into 2 inch lengths. (5) The collector according to claim 5, wherein the shaped concrete member reinforced with the shredded alkali-resistant glass fibers is formed by spraying concrete 1 and fibers onto a mold. 6. The collector of claim 5, wherein the fibers are shredded during the spraying operation. (7) The shaped concrete member has a layer of lightweight cellular concrete applied on the side opposite the glass member, thereby providing thermal insulation for fluid flowing through the passageway. Collector described in item 1. 8. The collector of claim 7, wherein the concrete layer and the glass member are bonded together using a bonding agent. (9) The collector according to claim 1, wherein the binder is a cement binder. 00) The collector of claim g, wherein the binder comprises an epoxy resin. (10) A collector according to claim 1, wherein a transparent protective cover is fitted over the glass member of the collector to reduce convective losses. A thin-walled concrete member characterized by being fabricated from a material having a matched coefficient of thermal expansion and reinforced with alkali-resistant fibers, which concrete member is capable of carrying a heat exchange fluid in cooperation with a glass cover member sealed thereto. a first surface shaped to provide a series of passageways); a selective solar footing characterized by high absorption and low radiation on one surface of the glass cover member; a transparent protective cover mounted over the glass cover member to protect the member and the coating thereon; and a concrete foam insulation layer applied to an opposite surface of the thin-walled concrete member; A solar collector in which the concrete, the alkali-resistant fibers, the glass cover member, the transparent protective cover and the foam concrete insulation have balanced thermal expansion properties over a temperature range of 0° to 200'C.