Introduction: Solar-OSE: Solar Concentrator for Steam Generation

News:
"Open Source Ecologie France" successfully completed a crowd-funding to buy the materials for a second improved prototype, including 4 modules like the one described in this instructable!
If you feel like contributing in any way to the project, be sure we will be very happy to welcome you!
 Thank you so much!

MAKER CONTACTS

Andrea Sannnuto, Hugo Frederich, Cyril Libert, François Veynandt, Philippe Gattegno on www.opensourceecologie.org

SHORT DESCRIPTION

This document describes the construction of a linear Fresnel solar concentrator. The prototype is adapted for heat needs between 100°C and 250°C.

UNDERSTANDING

Current levels of energy consumption are generally unsustainable. The use of solar energy favors a better distribution of the territorial economic activity. Meanwhile, many actual models are either designed for the industry, either for cooking in the South countries. Open Source Ecologie France researches and develops a solar concentrator made for an intermediary market, in order to make possible for little producers, artisans and micro-industries the use of solar energy. The prototype is designed for artisanal common uses : collective cooking, local food production, extraction of essential oils, jam cooking, jar sterilization, water purification, wood treatment, alimentation steam, other process using the vapor under 250°C. Vapor at lower temperatures can be produced in the prototype, the possible applications are heating the current water, product drying…

We propose a module capable of producing maximum 1 kW. The entire system will combine a specific number of modules in order to produce between 5 and 50 kW. The system must be equipped with the right components and automation, it has to fit the professional activities of the users; for example, it can be the main or the complimentary power energy. Its price has to be low enough in order to be easily adopted and shared.

GENERAL INFORMATION

SKILLS NEEDED

  • Metal work / Welding
  • Carpenter
  • Laser cutting
  • Plumbing
  • Electronics
  • Can help: basic knowledge in geometry, optics and material properties (related to a solar concentrator)

REQUIREMENTS

Some tasks need to be done with 3 persons, like assembling the structure.

A solar concentrator uses the sun’s light and it is useful in the regions with high solar radiation. A profitability calculation is useful.

Some methods are very specific to the project, but as well, there are commonly used methods (laser cutting; welding; metal cutting, drilling…)

Complementary to this manual, you can find online more information on:

  • Software, Electronics, Modelling (once finalized), documentation, licence details: see Github
  • discussions on our Forum
  • the documentation and collaborative writing in French is happening on our Wiki
  • technical requirements giving a comparison between the present demonstrator and the next prototype
  • the project in French:
  • you can subscribe to our newsletter and more on our website: www.osefrance.fr :)

COST

About 2000€ of material.

FABRICATION TIME

About 150h. 7 days 3 persons (or 4 persons during a week)

LEVEL OF TECHNICAL DIFFICULTY

Needs in terms of skills, intermediary to expert level:

  • An intermediary know-how to work the metal for the construction of the structure;
  • An intermediary know-how to install the electronics;
  • An intermediary to expert know-how to build the hydraulic circuit, depending on the pressure and temperature level of the usage.

MATERIAL AND TOOLS

INPUT

Steel

  • Tube 40x30 thickness:2 L1430 minimum length 1430 quantity:4 (Order : 1,5 x 6m)
  • Tube 25x25 thickness:2 L2130 minimum length: 2130 quantity:4 (Order : 2x6m)
  • Tube 30x30 thickness: 2 L2500 minimum length: 2500 quantity: 5 (Order: 2 x 6m)
  • Tube 20x20 thickness: 2 L2200 quantity: 4 + L1000 quantity 2. minimum length: 2200 (Order: 2.5 x 6m)
  • Tube_50x50 ép.3 L3m minimum length: 3m quantity: 2 (Order : 1x6m)
  • Jonc acier Ø8 quantity: 6M minimum length: 150mm (Order : 1x6m)
  • Flat (15 to 20) x (2 to 2,5) L2,5m minimum length: 2,5m quantity: 2 (Order: 20,58x2,5 L6m)
  • Flat (7 to 10) x (1 to 2) L2,5m minimum length: 2,5m quantity: 1
  • Flat 20x3, L100mm quantity 2
  • Flat 30x5, L2150mm quantity 1
  • Profile. interior dimension : (20 à 35) x (30 à 50) L 2,2m quantity: 2; L 100, quantity 2. minimum length: 2,2m (Order: dim int 27 x 55,5 thickness: 3. dim ext 30 x 58,5)
  • Stainless steel bar 8000 mm long, 8mm diameter

Aluminium

  • Square tube 2000m long, 20x40.
  • 2000x 3000 (2000x2000 + 3 times 340 x 680 mm + 2 times 230 x 125mm + 2 times 50 x 50 mm) Mirror plate, anodized aluminum
  • 0.2 mm thick Plate (printing offset plate) 700mm x 2100mm + 300x250mm

Screws

  • Screw M10 L80. Quantity: 2
  • Screw M8 L100. Quantity: 12
  • Screw M6 L70. Quantity: 32
  • Screw M6 L60. Quantity: 40
  • Screw M6 L70 quantity: 40
  • Screw M6 L25. Quantity: 20
  • Screws M5. Quantity :12
  • Screw CHC (pan hex head) M4 L20 quantity: 50
  • Screw M4 countersunk hex head. Minimum length: 10 quantity: 20
  • Screw M3x16. Quantity : 80
  • nut M8. Quantity : 42
  • nut M6. Quantity :200
  • nut M5. Quantity :12
  • nut M4 quantity : 150. (60 in screws H M4 (thickness 3) + 50 in countersunk head screws M4 (thickness 3)
  • Washers M3 quantity : 300. Ø9-Ø3,2-thickness:0.7
  • Washers M4 quantity: 120. Ø12-Ø4,4-thickness:1
  • Washers M6 quantity : 250. Øext 13.8 et 18
  • threaded rod M8 quantity: 1000mm. minimum length: 400mm

Wood

  • Wood plate (for example laminated structural wood), minimum dimension: 810x500 (thickness:.10) compatible with laser cut. Quantity: 2

Pipes

  • 1 brass tube with an exterior diameter of 55 mm and a length of 1900 mm
  • 4.5 m copper pipes, minimum length 3m.

Other

  • Anti-rost painting
  • sealant PVC alu special for glazing
  • Height adjustable feet M8. Threading M8 L25 – total height 35mm quantity: 8
  • Glass cover 1000x250x4 quantity:2
  • 2000 mm length of a 2 mm diameter steel cable
  • “element to adjust length of the cable” 1
  • Glue
  • Rockwool (or other fire resistant insulation material, 300°C) insulation 10 cm thick (600x1000) quantity 2.
  • Cotton Insulation (for steam pipe) 10 cm thick, 600x1000, quantity 1.
  • Aluminum adhesive tape (quote in text)
  • Adhesive tape
  • Auto-lubrifying bushing. Quantity: 40

TOOLS

Regular metal and wood workshop tools, including:

  • Hack saw
  • Grinder
  • Drilling machine and set of drills for metal: 3mm, 4mm, 5mm, 6m, 8mm, 10mm, 20mm. Drills for wood: 4mm, 10mm.
  • Bristol paper
  • Cutter
  • Measuring devices : over 3 meters tape measure, 1 m ruler, square and metallic protractor
  • 3 clamps
  • Plunging saw

Plus:

  • laser cutter/printer

OUTPUT

The CONCENTRATOR:

  • mirror field
  • receiver
  • tracking system
  • demonstration…

+ WASTE: unused mirrors, metal pieces, unused pieces of wood, glue, sealant

PARTS OF THE DOCUMENTATION

1. Mirror field

1.1. Support structure (1day)

1.2. Mirror facets (1day)

2. Receiver

2.1 Support structure (1day)

2.2 Skeleton of the receiver (1day)

2.3 CPC Reflector

2.4 Absorber tube

2.5 Assembling of the receiver (3h)

3. Tracking system (2 days)

4. Usage demonstration

Step 1: (1.1) Cutting the Square Tubes

1–MIRROR FIELD (Time needed: 2 days) > 1.1 Support (Time needed: 1 day)
Note: The support is made of two frames: repeat or double the steps 1 to 6, afterwards finish the assembling with the step 7.

Material

  • 2 main square tubes 25x25 mm
  • 2 square tubes for the support 30x40 mm (the mirrors are fixed on it)

Tools

  • Hack saw
  • Grinder

How to?

Use the grinder to cut at the length of 2130 mm the two main squared tubes and at the length of 1430 mm the 2 square tubes for the support.

Step 2: (1.1) Mark and Drill the Holes on the Square Tubes for the Support (30x40 Mm)

1–MIRROR FIELD (Time needed: 2 days) > 1.1 Support (Time needed: 1 day)
Note: The support is made of two frames: repeat or double the steps 1 to 6, afterwards finish the assembling with the step 7.

Material

  • square tubes for the support 30x40 mm, length of 1430 mm

Tools

  • Drilling machine
  • Bristol paper
  • Printer/laser cutting
  • Adhesive tape

Goal

The two square tubes for the support have to be drilled with two holes every 143 mm. The position of the holes assures that the mirrors are parallel. It is important to work precisely so that the mirrors reflect the light in the same line.

How to?

Print the template. Use the available drawing file which is composed of two parts; it is enough to put the two parts one next to each other. Put the template on the square tube and make sure that the paper is fixed to the edges and the extremities of the tube. Fix the template with the adhesive tape. Attention: if the square tube is welded from the interior on one face, this face has to be drilled first. Otherwise, if the opposite face is drilled, the drill will be deviated near the welding point.

Punch precisely the holes marked on the template with a needle and a hammer.

Use a pillar drill with a diameter of 6 mm. The drill should be long enough to drill the square tube on the both sides. Attention, if the tube has a welding point on the interior side, make sure not to drill there while making the second hole.

Step 3: (1.1) Mark and Drill the Holes on the Extremities of the Main Square Tubes

1–MIRROR FIELD (Time needed: 2 days) > 1.1 Support (Time needed: 1 day)
Note: The support is made of two frames: repeat or double the steps 1 to 6, afterwards finish the assembling with the step 7.

Goal

The goal is to drill two holes on each extremity of the four tubes; the holes help to maintain the square shape.

How to?

Scratch the holes position on the tubes as indicated in the 3D model. The two holes are placed at 10 mm and at 30 mm on the tube having a width of 40 mm and they are centered at 12.5 mm on the tube having a width of 25 mm. With these holes, the tubes are fixed on their extremities.

Use a pillar drill of 6 mm, long enough to drill the square tube on both sides (if necessary, it should have at least 60 mm to drill simultaneously the two tubes put one above each other).

Step 4: (1.1) ASSEMBLING All the Tubes

1–MIRROR FIELD (Time needed: 2 days) > 1.1 Support (Time needed: 1 day)
Note: The support is made of two frames: repeat or double the steps 1 to 6, afterwards finish the assembling with the step 7.

Put all the square tubes on a table: begin with the tubes of 25x25 mm, afterwards put under the tubes of 30x40 mm, assuring that the surface of 40 mm is connected to the extremities of 25x25 mm. Fix them at each angle with a screw of M6 having a length of 60 mm. The tubes can be adjusted if the right angle is verified with a protractor. If the second screw does not enter in the two tubes, the hole alignment should be adjusted by passing the stand alone drill through. Repeat the procedure to all angles in order to complete the fixation.

Step 5: (1.1) Cut the Wood Support Pieces for the Motors and the Axes of the Mirror

1–MIRROR FIELD (Time needed: 2 days) > 1.1 Support (Time needed: 1 day)
Note: The support is made of two frames: repeat or double the steps 1 to 6, afterwards finish the assembling with the step 7.

Material

  • Wood board
  • Laser cutter

How to?

Cut with the laser cutter 20 wood support pieces for the motors and 40 wood support pieces for the axes of the mirror. It is necessary 40 pieces in order to assure one piece to each extremity.

Step 6: (1.1) Fix the Wood Support Pieces on the Frame

1–MIRROR FIELD (Time needed: 2 days) > 1.1 Support (Time needed: 1 day)
Note: The support is made of two frames: repeat or double the steps 1 to 6, afterwards finish the assembling with the step 7.

How to?

Fix with 2 screws the wood support pieces for the motor on the tube, exterior part and the wood support pieces for the axes of the mirror as indicated on the 3D view. The motor and the axis of the mirror are fixed under the tube, so their wood support pieces should overpass above.

Step 7: (1.1) Assembling the Two Frames

1–MIRROR FIELD (Time needed: 2 days) > 1.1 Support (Time needed: 1 day)
Note: The support is made of two frames: repeat or double the steps 1 to 6, afterwards finish the assembling with the step 7.

How to?

Two frames are constructed as indicated in the steps 1 to 6.

They are assembled on tubes of 50x50 mm, cut and drilled as indicated in the 3D model.

Step 8: (1.2) Setting Up the Square Tubes

1–MIRROR FIELD (Time needed: 2 days) > 1.2 Mirror (Time needed: 1 day)
Material:
- Square tube made of aluminum
- Stainless steel bar
- Wood board
- Mirror sheet

Cut to a length of 2000 mm the aluminum tubes of 40x20 mm (or buy them with these dimensions). Drill a hole of 5 mm centered on the width, at 100 mm from each extremity. Tap (thread) this hole, made for a screw with a diameter of 6 mm (M6).

Step 9: (1.2) Preparation of the Axes

1–MIRROR FIELD (Time needed: 2 days) > 1.2 Mirror (Time needed: 1 day)
Material:
- Square tube made of aluminum
- Stainless steel bar
- Wood board
- Mirror sheet

Cut 40 bars with a diameter of 8 mm and a length of 200 mm. Make a flat spot at 147 mm from the bar’s extremity; the flat spot will be positioned to the exterior of the aluminum tube.

Step 10: (1.2) Preparation of the Supports for the Axes

1–MIRROR FIELD (Time needed: 2 days) > 1.2 Mirror (Time needed: 1 day)
Material:
- Square tube made of aluminum
- Stainless steel bar
- Wood board
- Mirror sheet

Choose a wood board having a thickness of 100 mm, use the laser cutter to make 40 interior holds (rounded edges) and 40 exterior holds (straight edges), according to the cutting file.

Step 11: (1.2) Preparation of the Mirror Facets

1–MIRROR FIELD (Time needed: 2 days) > 1.2 Mirror (Time needed: 1 day)
Material:
- Square tube made of aluminum
- Stainless steel bar
- Wood board
- Mirror sheet

With a cutter or a plunging saw, cut strips of 2000 mm long and 100 mm large from the plate of mirrors. If the plate doesn’t have the right length, two flats of 1000 mm long are cut to cover each part of the mirror. It’s important not to damage the mirror, in order to keep the faces of the mirror plane. For example, a deviation of 0,1° generates a misalignment of 1 cm on the receiver.

Step 12: (1.2) Assembling of the Axes

1–MIRROR FIELD (Time needed: 2 days) > 1.2 Mirror (Time needed: 1 day)
Material:
- Square tube made of aluminum
- Stainless steel bar
- Wood board
- Mirror sheet

The 40 bars are the axes; for all of them, insert a hold close to the flat spot; this part will be on the extremity that will enter firstly in the square tubes. Insert a second hold, 47 mm from the other extremity of the bar. Put the bar assembled with the two holds on a plane zone, with the bar in the lower part, to ensure that the holds are parallel between them. In this position, orientate the flat spot to the upper part (photo). Glue the holds with araldite type glue.

Step 13: (1.2) Assembling of the Mirror Facets

1–MIRROR FIELD (Time needed: 2 days) > 1.2 Mirror (Time needed: 1 day)
Material:
- Square tube made of aluminum
- Stainless steel bar
- Wood board
- Mirror sheet

Insert the bars with the holds on them in the aluminum tubes. The bar must be tangent on the opposite side to the drilled hole. In this way, the plat spot is in front of the hole. Turn the screw in the drilled hole until it fixes the bar on the plat spot. The bar is fixed laterally with the holds and it is fixed in height on its entire length with the screw.

Glue the rectangular mirror facets on the aluminum tubes. Make sure that they are centered on the width of the tubes.

Step 14: (1.2) Mounting of the Mirror Facets on the Support Frames

1–MIRROR FIELD (Time needed: 2 days) > 1.2 Mirror (Time needed: 1 day)
Material:
- Square tube made of aluminum
- Stainless steel bar
- Wood board
- Mirror sheet

Mount the facets on the frames by passing the axes in the holes of the wood supports using autolubrifying bearings.

(1.2) Possible improvements

Add a diagonally tube to the squared structure, in order to prevent the deformable movements. The mirror facets added on the squared aluminum tubes of 40x20 mm is an improved solution. The first solution, a half PVC tube (building them took 10 hours). Cut in half 10 PVC tubes on their length (a template should help cutting correctly the tube), the result is 20 mirror supports. Cut 6 wood pieces in shape of half-disc for each mirror face, with a hole in order to add the motor’s axe. The axe is maintained by two wood pieces at each extremity. Another two wood pieces reinforce the structure and maintain the mirrors. The mirror strips with a width of 100 mm are collected on the surface of the half PVC tubes and they are leaning on the 6 wood pieces. The issue is the low torsion resistance of the mirror face; the reflected light will not be collected on the same line, lowering the optic performances.

Step 15: (2.1) Preparation of the TEPEE Squared Tubes

2- RECEIVER (Time needed: 3 day) > 2.1 Structure support (1 day)

Cut at a length of 2300 mm 4 square tubes: a right cut and a 45° cut.

Drill the holes according to the 3D model in order to assemble the legs of the “tepee” (1 hole/square tube), the receiver’s fixation (1 hole/square tube), the fixation of the inferior square tube across the length (2 holes/square tube), the fixation of the transversal flat (1 hole/ square tube, 800mm from the bottom, measured at the furthest point of the 45° cut). Check the total length of the square tube: the length necessary to drill the holes is measured from the bottom of the leg.

Cut 4 flats with 30 mm large, 40 mm long and 5 mm thick and check the dimensions. Drill and tap the flats at 10 mm from the edges to fix an adjustable leg made of a screw with a diameter of 8 mm. Weld the flats on the edges cut at 45°. By doing this, an adjustable horizontal leg is obtained.

Step 16: (2.1) Preparation of the Inferior Square Tubes, the Reinforcement, the Transversal Flat and the Transversal Cable

2- RECEIVER (Time needed: 3 day) > 2.1 Structure support (1 day)

Cut the inferior square tubes: 4 square tubes 20x20x2200 mm. Possible improvements with rectangular tubes 20x30 or 20x40 mm. Weld two square tubes one next to each other in order to form a rectangular tube. Drill them on the edges as described on the 3D model.

Cut the reinforcement square tubes: 2 square tubes 20x20x1000 mm with a 45° angle on the extremities. Cut two flats 20x3 mm, having a length of 100 mm and 2 steel angles (L shaped) 30x60 mm, having a length of 100 mm. Drill the four pieces according to the photos/3D model. Weld the steel angle and the flats at both extremities of the 1000 mm square tube in order to finish the reinforcement tubes. Check that there is an angle of 45° between the exterior surface of the flat and the square tube, as well between the exterior surface of the steel angle and the square tube. In this way, the right angle is warranted between the “tepee” square tube and the inferior square tube.

Cut the transversal flat: a flat of 30x5 mm having a length of 2150 mm. Drill it at the extremities according to the 3D model: the distance between the holes is 2120 mm (at 1500 mm from the hole of the assemblage “tepee”).

Cut approximatively a length of 2000 mm of the 2 mm diameter cable. Adjust its length in order to obtain a total length of 2120 mm between the fixation holes from the “tepee” squared tubes: make a loop at one edge and pinch the clamping ring on the cable. Measure the length of the adjustable element in an open position (Lmax) and cut the cable at a length of (2120 - Lmax + 40 mm) in order to form a loop at a final length of (2120 - Lmax).

Step 17: (2.1) Assembling of the Structure

2- RECEIVER (Time needed: 3 day) > 2.1 Structure support (1 day)

Assemble horizontally with a 10 diameter screw, two by two the square tubes to form the two “tepee” supports. Screw the adjustable legs on their support, located under the “tepee” squared tube.

Fix the inferior square tubes at the base of the tepee’s square tubes: the distance between the tepees is set. Position the 100 mm reinforcement square tubes with the clamps as can be seen in the photo. Check that: (1) the tepee square tube and the inferior square tube make a 90° angle, (2) the flat and the angle are parallel, as well the “tepee” square tube and the inferior square tube. Drill the “tepee” square tube and the inferior square tube through the hole situated on the reinforcement element (flat and angle). If the drill is not long enough, drill firstly the hole from the reinforcement element. Afterwards, mark the opposite point to the first hole and drill the second hole from the other side of the square tube.

2 persons lift the structure to form the tepee. A third person attaches the transversal flat with two screw in the north side, where are the reinforcements. Afterwards, he/she fixes the cable in the south side and he/she adjusts its length to 2120 mm. The structure should keep its balance, but it is better if someone holds the tepee from the south side. During this time, the other two persons can bring the receiver and position it on the tepee. This final step allows to keep the structure stable.

Step 18: (2.2) Main Beam /30minutes/

2- RECEIVER (Time needed: 3 day) > 2.2 Skeleton of the receiver (4 hours)

Cut the 30x30x2300 mm square tube.
Drill the fixation holes of the tepee. Drill and tap at 5 mm diameter the fixation holes of the junction.

Step 19: (2.2) Lateral 'L' Profiles /1h30/

2- RECEIVER (Time needed: 3 day) > 2.2 Skeleton of the receiver (4 hours)

Cut two L profiles 30x60 mm, thick of 3 mm and long of 2100 mm.

Drill and tap the fixation holes of the exterior cover, screw with a diameter 4 mm.

Drill the fixation holes at the junction, as depicted in the 3D model. Improvement: drill 2 holes on the side and none on the bottom of the L.

Weld a flat at each edge of the L (for the fixation on the “tepee”…).

Step 20: (2.2) Junction of the Main Beam and the Lateral L Profiles /1hour/

2- RECEIVER (Time needed: 3 day) > 2.2 Skeleton of the receiver (4 hours)

Cut, drill, weld according to the 3D model.

Step 21: (2.2) Hanger /1Hour/

2- RECEIVER (Time needed: 3 day) > 2.2 Skeleton of the receiver (4 hours)

Print the 10 hangers at the cutting laser. The material used is a wood board (for example laminated structural wood) with a thickness of 10 mm.

Cut shapes of 2 hangers (with a cutting laser or manually), without emptying them. They are needed for the secondary reflector in order to close the receiver on its edges.

Link to the file for printing!

Step 22: (2.3) Cutting the Mirror Sheet (15 Minutes)

2- RECEIVER (Time needed: 3 day) > 2.3 Reflector CPC (3hours)
Goal:
To build the secondary reflector Composed Parabolic Concentrator (CPC)
Material and tools:
- Skeleton of CPC
- Aluminum mirror sheet finishing
- Cutter
- 1 m ruler, square and metallic protractor
- 3 big clamps
- Drilling machine and drill with a diameter of 4 mm
- 30 screws M4 and spacers

With a cutter, cut a 340x680 mm rectangle of mirror sheet. Mind to protect the reflective surface of the mirror during the operation and to work on the back side. One needs to run the cutter several times to bite the metal and to fold back and forth in order to detach it.

Step 23: (2.3) Marking the Folding Lines (30 Minutes)

2- RECEIVER (Time needed: 3 day) > 2.3 Reflector CPC (3hours)
Goal:
To build the secondary reflector Composed Parabolic Concentrator (CPC)
Material and tools:
- Skeleton of CPC
- Aluminum mirror sheet finishing
- Cutter
- 1 m ruler, square and metallic protractor
- 3 big clamps
- Drilling machine and drill with a diameter of 4 mm
- 30 screws M4 and spacers

With the cutter, trace the folding lines following the plan below. Run the cutter in order to mark the lines without going through and fragilizing the metal.

Step 24: (2.3) Drilling (30 Minutes)

2- RECEIVER (Time needed: 3 day) > 2.3 Reflector CPC (3hours)
Goal:
To build the secondary reflector Composed Parabolic Concentrator (CPC)
Material and tools:
- Skeleton of CPC
- Aluminum mirror sheet finishing
- Cutter
- 1 m ruler, square and metallic protractor
- 3 big clamps
- Drilling machine and drill with a diameter of 4 mm
- 30 screws M4 and spacers

Drill the fixation holes of the mirror using the following method. The oblong holes can be made by drilling with the drill tilting to each side until a hole with a 7 mm diameter is obtained. (see the suggestions at the end of the section related to this subject).

Step 25: (2.3) Folding (1hour)

2- RECEIVER (Time needed: 3 day) > 2.3 Reflector CPC (3hours)
Goal:
To build the secondary reflector Composed Parabolic Concentrator (CPC)
Material and tools:
- Skeleton of CPC
- Aluminum mirror sheet finishing
- Cutter
- 1 m ruler, square and metallic protractor
- 3 big clamps
- Drilling machine and drill with a diameter of 4 mm
- 30 screws M4 and spacers

We propose a method that uses simple tools. A folding press can do the job if it folds uniformly the mirror. While doing the folding manually, it is easier to work in a team of two persons in order to fold correctly the mirror.

Choose a rigid table that does not bend and has a right angle edge. Start with a fold on the central line. Put the mirror sheet with the reflecting part on the backside, in order to see easily the dashes marked on the sheet. Fold following the first apparent fold (the second central fold is marked under the support board). Protect the mirror with paper sheet. Keep firmly the mirror sheet under the board with a clamp on each edge. Choose a rigid board, having a right angle edge and a length greater than the mirror sheet; check that the board is against the edge of the table. Press underneath to obtain a mirror sheet fold between 20 and 30° (approximatively half of 45°). The pressure should be uniform on the entire surface, in order to assure a regular fold.

Continue with the same method for the second fold: it is enough to release the mirror sheet and take it out a few mm so that the dash lines appear. Reposition the mirror sheet. Pressing near the fold is very important during this step. The first fold can be reinforced, but it is necessary to impose a second angle between 20 to 30°, so that the total angle is 45°.

Apply two times the same method for each of the lateral folds: fix firmly the mirror sheet on a lateral band of 15 mm. This allows a better grip when folding the mirror sheet. Impose a 90° angle. Press against the dashed line.

Step 26: (2.3) Bending (1hour)

2- RECEIVER (Time needed: 3 day) > 2.3 Reflector CPC (3hours)
Goal:
To build the secondary reflector Composed Parabolic Concentrator (CPC)
Material and tools:
- Skeleton of CPC
- Aluminum mirror sheet finishing
- Cutter
- 1 m ruler, square and metallic protractor
- 3 big clamps
- Drilling machine and drill with a diameter of 4 mm
- 30 screws M4 and spacers

The 0.5 mm sheet is rigid. A preforming is necessary to maintain the reflector in the position imposed by the hangers. The method presented uses simple tools that give a good result (any suggestion for improvement is welcomed). It is easier to work in a team of two persons in order to bend the mirror on its entire length.

Install a rigid board large of maximum 150 mm, elevated by 100 mm over the table. This allows to install a part of the reflector, without being hindered by the other scroll.

A first bending is imposed by the tube having a diameter of 100 mm: for example, use an evacuation tube made of PVC. Put the mirror sheet with the reflecting part on the upside. Align the first central fold on the edge of the board in order to leave forward the free scroll. Protect with paper the reflector. Fix the tube on the board edge, as near as possible to the center of the CPC.

Check that the tube is parallel to the mirror sheet. Clench correctly the clamps (with a height of 250 mm). With a large board or a metal squared tube, lift the scroll blocked under the tube. Tackle the mirror sheet against the tube on its entire length in order to impose a regular bending. Insist in the final part so the bending goes until the lateral part of the CPC.

Repeat the action on the other scroll.

A second bending around a 40 mm tube is necessary in the central part. Put the 40 mm tube in the same position as the previous tube. Attention to put the tube as close as possible to the board edge. In this way, the mirror deformation will be closer to the center. In order to improve this bending, it is possible, afterwards, to put the mirror the other way: pinch it by letting approximately 70 mm of the mirror outside; measure from the central fold. Thus, by lifting the mirror, tackle the mirror sheet on the tube until the center. In practice, the result is harder to obtain because in this configuration, one does not have a lever arm. As well, attention must be paid not to modify the folding, because the mirror can break down.

Repeat the operation on the other scroll.

The secondary reflector CPC is ready to be assembled.

Step 27: (2.4) Absorber Tube

2- RECEIVER (Time needed: 3 day) > 2.4 Absorber tube and elements of hydraulic circuit (3h)

Cut a brass tube with an exterior diameter of 55 mm and a length of 1900 mm. The pipe is originally shiny.

Weld the fittings on the edges, according to the photo. Make sure one fitting is at the bottom, and the other one at the top: this enables to feed liquid water from the lower part and extract water vapor from the top.

Once the pipe is welded, you need to darken its external surface, so it becomes as absorptive (black) as possible. This is very important as we want as much solar light to be absorbed on the pipe to heat the water inside. Apply an oxidizing solution suitable for brass (easily available on the market). Let the oxidizing solution dry for a couple of days if possible. Remove the traces of the oxidizing solution with a wet paper. Or just follow the instructions on your oxidizing solution.

Step 28: (2.4) Elements of Hydraulic Circuit

2- RECEIVER (Time needed: 3 day) > 2.4 Absorber tube and elements of hydraulic circuit (3h)

Cut the copper pipes:
+ 3 m length for the water alimentation
+ 15 cm for the south connection (water)
+ 15 cm for the north connection (steam)

Arrange the connection to the edges of the tubes, as seen on the schema/photos of the hydraulic circuit.

The plumbing complementary elements depend on the application connected to the solar boiler.

Step 29: (2.5) Setting the Hangers on the Squared Tube

2- RECEIVER (Time needed: 3 day) > 2.5 assembling of the receiver (3h), Step 1

Cut the squared tube at a length of 2.2 m.

Put the 10 hangers on the squared tube, with a spacing of 22 cm.

Step 30: (2.5) Setting Up the Lateral Fixation Metallic Flat of the Secondary Reflector

2- RECEIVER (Time needed: 3 day) > 2.5 assembling of the receiver (3h), Step 2

Cut the flat at a length of 2 m. Drill it according to the plan: 10 holes with a diameter of 4 mm, 10 mm from the edges, 220 mm the distance between them. Mill the entry of the hole with a drill having a diameter of 8 mm. It is important that the screw with the flat head covers the surface of the flat, without surpassing it. This is the position that creates the right rigidity to the receiver, by posing a precise distance between the hangers. Attention to drill in the same manner the two flats, so that the hangers are perpendicular to the receiver axis: drill both together with a pillar drill.

Step 31: (2.5) Fixation of the Secondary Reflector

2- RECEIVER (Time needed: 3 day) > 2.5 assembling of the receiver (3h), Step 3

Put the 3 preformed portions of the reflector in their set up, with an overlap similar to the roof tiles “top-below”. Begin by fixing entirely one edge: put the lateral flat on the side of the preformed reflector. Put the screw in each hole, in order to fix the square tube. Pinch the nut to screw without damaging the hanger.

Step 32: (2.5) Setting Up the Absorber Tube in the Cavity (adjustment of Its Lateral Position and Its Height)

2- RECEIVER (Time needed: 3 day) > 2.5 assembling of the receiver (3h), Step 4

Prepare the two supports as described below:

Between two tubes with a diameter of 55 mm clamped in a nut, curve in the center a U threaded rod having a length of 320 mm and a diameter of 6 mm. File the interior of the U rod in order to smooth the contact surface with the absorber tube. Prepare a metallic flat with the dimensions of 20x90 mm, drill two centered holes with a diameter of 8 mm at a 68 mm distance one from another. Prepare the two flats with the dimensions 120x20, put them in the nut in order to fix them in the main beam: 1 central folding at 90° and at a distance of 30 mm, two folds at 45°. Drill the two plats at a distance of 68 mm, with a diameter of 8 mm. Drill the secondary reflector at 520 mm from each extremity, symmetrical to the central axis. Insert the U threaded rod in the holes.

Put the flat on the threaded rod, afterwards the nut in each branches of the threaded rod. Put the U threaded rod in the holes of the secondary reflector; insert two nuts, put the two flats in order to pinch the main beam of the receiver. Complete with two nuts.

Put the absorber tube as follows:

Put the receiver on the table, on the opposite side: the secondary reflector upwards. Slip the tube between the two U. You can turn over the receiver, to suspend the tube and to access easily the top screws. Adjust the position of the tube, in order to be centered, horizontal and as close as possible to the secondary reflector, without touching it (even the screws, to avoid the thermal bridge).

Step 33: (2.5) Setting Up the Reflective Covers on the Edges of the Receiver

2- RECEIVER (Time needed: 3 day) > 2.5 assembling of the receiver (3h), Step 5

Cut a mirror sheet as indicated in the figure (230x125 mm, angles from the side smaller than 40mm).

Drill holes having a diameter of 4 mm: on the inferior part 18 mm from the lower edge, 8 mm from the lateral edge, on the superior part 40 mm from the central part, and 10 mm from the upper edge. Drill a centered hole having a 20 mm diameter, corresponding to the height of the absorber tube’s exit: the nozzle height is different at each extremity (between the water entry and the vapor exit). We suggest to measure the precise position from the real position of the absorber tube.

The interior screws are inserted up the pre-drilled hole of the hanger, where the support screw of the secondary reflector is inserted. For the upper screw, drill a hole in front of the holes of the mirror sheet.

We can seal the junction of the secondary reflector with the final cover, by applying a temperature resistant filler (at least 300°C).

Improvement: instead of cutting the sheet at 125 mm, cut it at 140 mm and fold it at 90° towards outside, in order to handle the junction from the extremity of the mirror field. In that way, we can foresee a glass longer with 3 cm in order to close better the cavity from the edges.

Step 34: (2.5) Setting Up the L and the Junctions

2- RECEIVER (Time needed: 3 day) > 2.5 assembling of the receiver (3h), Step 6

Put the Ls on both sides of the receiver. Fix the junctions on the main beam with two screws 20 mm long and a diameter of 5 mm. Screw the junctions in the lateral and inferior parts of the Ls. If the junctions are too little in the Ls, adjust by using the spacers. Verify that the distance between the Ls and the downside of the secondary reflector is constantly greater than 5 mm: this distance is necessary to assure that the glass of 4 mm thick will not break.

Step 35: (2.5) Putting the Thermal Insulation Around the Cavity

2- RECEIVER (Time needed: 3 day) > 2.5 assembling of the receiver (3h), Step 7

Take a plaque of stone wool (alternative material: wood wool, cellulose wadding; the cotton is not appropriated because of the high temperatures), thick of 10 cm. Cut a strip large of 570 mm and 9 times a length of 210 mm. Make thinner the strip on its edges and on the central part, as mentioned in the schema (thickness of 3 cm on the edge, inclined cut on 12 cm width + 5 cm cut width and depth on both sides of the center). Make the strip thinner where the support of the absorber tube should come.

Use a mask and a pair of gloves to avoid breathing the carcinogenic fibers. Try to handle the material as gentle as possible, in order to limit the dust. Think about others if you are not working alone.

Step 36: (2.5) Setting Up the Water Tube

2- RECEIVER (Time needed: 3 day) > 2.5 assembling of the receiver (3h), Step 8

The alimentation tube for water is inside the receiver as depicted in the photo. We can make the necessary notches in the hanger with a drill. (Improvement: include the notches in the cutting plan of the hanger). Make sure that the connection elements from the south part are well sized: the surfaces have to be parallel without forcing them. This will allow obtaining the sealing of the south connection. The plumbing elements should be able to be included inside the receiver.

Step 37: (2.5) Sealing With the Cover

2- RECEIVER (Time needed: 3 day) > 2.5 assembling of the receiver (3h), Step 9

We can use a cover, made of one piece of fine metal sheet with a width of 700mm and a length of 2100mm, or several pieces connected one to each other. Drill the cover in order to fix the holes of the L. We can trust the plan, or position on a table the Ls on the cover. Mark the position of the holes. Drill the holes having a diameter of 4 mm. Put here the cover on the receiver. Screw one by one and begin from one side in order to finish to the opposite side. Adjust correctly the position of the holes in the cover. While putting the screws, add the spacers.

Add the thermal insulation on the extremities of the receiver. Seal the cover on the edges: cut a metal sheet having the shape of a hanger, using a shape of a hanger or the negative of it. Adjust the position of the holes in the cover. Add the horizontal metal sheet that will be blocked between the Ls, in order to seal the lower part of the receiver beyond the glass.

Step 38: (2.5) Setting Up the Glass (with a Junction Under and Above)

2- RECEIVER (Time needed: 3 day) > 2.5 assembling of the receiver (3h), Step 10

Before putting the glass, check the fittings’ sealing on the way out of the absorber tube. Rise the pressure in tube with a bike pump. Find the holes with soapy water.

Put the receiver, with the secondary reflector upside-down. Unscrew in the 4 coins the two fixation screw placed between the L’s and the junctions. Put the Ls on the table, letting the cover attached. Put a bead of glazier sealant (or high temperature sealant), preferably white, on the perimeter of the secondary reflector: laterally, on the metallic flat fixing the CPC, on the hangers and eventually on the extremities, without dirtying the reflector. Put the glass on the bead of sealant, to close the cavity of the secondary reflector. Add another bead of sealant on the edges of the glass. Reposition the Ls and screw them.

Turn the receiver by suspending it on its extremities. Check that the glass is still centered. Let it dry.

Step 39: (2.5) Placing the Receiver

2- RECEIVER (Time needed: 3 day) > 2.5 assembling of the receiver (3h), Step 11

Two persons must carry the receiver, by taking it of the central beam. Put it on the tepee. Pass on the screws. Widen the holes or use smaller screw if necessary.

(2.5) Points to improve

To drill the slotted holes without damaging the driller, drill two holes by punching the center of the holes at a distance of 3 mm (the second hole is often less successful, a soft clipping may improve the result ) or 4 mm (the clipping is necessary to remove the material between the holes).

Hole position: maybe drill the holes after drilling the flat? Normally, the slotted holes give already a margin.

Folding the secondary reflector can be improved. The mirror sheet is difficult to work with, especially in its central part. With the proposed method, the mirror doesn’t follow perfectly the shape of the hanger on its central part. Another idea is to work separately the two scrolls to form easier the strong bending in the center. The central fold should be formed after the bending.

In the method presented, the central bending being difficult to obtain, the necessary central fold is less important. We propose to give a smaller angle compared to the theoretical shape, the angle of 45°. By giving the theoretical angle of 90°, the reflector might break during the assemblage because of the sudden unfold to adjust on the hanger.

Folding with a machine is not good enough. After during our test, the fold is not sharp-edged. The machine might twist the mirror in an unwanted direction.

For the clamped bending, a 5 cm tube (instead of 4 cm) might as well be used. This would allow to the receiver tube.

Position of the square tube: by putting it on the flat, instead of the point allows to reduce the height of the CPC and even the rigidity of the hangers.

Step 40: (3) Tracking System (2days)

3- Tracking system (2days)

Concerning the electronics, the current development is available in the files available here: https://github.com/osefrance/SolarConcentrator/tr...

Main elements of the electronic circuit (documented with "fritzing")

  • Motors
  • Optical sensor
  • SD disk clock
  • Driving motor system
  • Serial extensor

Mechanical elements of the tracking system

  • Mechanical circuit
  • Direct drive

Programing

  • Software code - arduino

Step 41: (4) Applications

4- Application: Usage demonstration

Many applications can be powered by solar steam. Several examples have been developed by Soleil Vapeur in opensource. The documentation is available online here: http://jean.boubour.pagesperso-orange.fr/ (it is mostly in French, volunteers for translation can contact Jean Boubour)

4.1 Steam sterilizer

See part 2, chapter III in Soleil Vapeur documentation.

4.2 Cooking pot (1day)

See part 2, chapter I in Soleil Vapeur documentation.

4.3 Ice machine

See part 3 in Soleil Vapeur documentation.

4.4 Other applications

See other parts of Soleil Vapeur documentation.

You can contact us or do your own development to adapt your usage to solar steam.

Enjoy using your solar vapor !

Step 42: THANK YOU

THANK YOU

List of contributors to the project

Design, Fabrication et Documentation

Andrea Sannuto, Hugo Frederich, Cyril Libert, François Veynandt, Oriane Mollet, Alain Tabutaud, Philippe Gattegno, Jean Walter, Jean Boubour, Simon d'Hénin, Fabien Berthome, Clément Zion, Chloé Lequette, Amandine Hacquebart, Thomas Lemaire, Chérif Belacel, Remi Rodrigues, Timm Wille, Armenia Siladi,Manuella Cunha, Pierre Lebon, Manuella Yamada, Gaétan Barbe, Isabelle ?, Alex Shure, Damien Arlettaz??, Julien Petitjean, Nour Laledj, Nounja Jamil, Jonathan Estassy, Myriam Van Haaren, José Diaz

Administrative support, Funding, Communication

Maud Foresti, Yann Giang, Michaël Jeanjean, Haja Leca, Claude Dos Reiss, Jean-Jacques Valette, Yoan Rihouay, Manon Larchevêque, Guillaume Forcier, Pierre-Alexandre Maizière, Jinghui Yang, Manon Piazza, Michelle hauteville, Nouria Kal, Alise Ponsero, Charlotte Pellefigue, Camille ?, Thibaut Brousse, Thomas Savey,

LICENSE

Creative commons, Attribution, Share alike

LIST OF SOURCE FILES

Check the up-to-date files on Github: github.com/osefrance/SolarConcentrator