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# System prepended metadata

title: Prototype Evolution

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![](https://i.imgur.com/SP0nBj8.png)
#### Developing free Open Source Hardware Designs for solar-thermal desalination that can be manufactured and innovated locally in Makerspaces across the world
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# Acraea 3.0
### [--> View 3D Model](https://a360.co/3D5IJ1k)

![](https://hackmd.io/_uploads/HyA25lnFn.jpg)


Acraea 3.0 Prototype is an open source hardware device that is improving several parts from Acraea 2.0 feeding system as the most critical module.
The iteration works towards laboratory tests of water quality and performance.




# Overview
| Specs    |         Acraea 2.0         |              Acraea 3.0               |      [Acraea 4.0](https://hackmd.io/LGknfXx9RTWKIzE0HvnMqw)                       |
|:-------- |:---------------------------------:|:-------------------------------------:|:-------------------------------------:|
| Goal     |      Proof of Concept      | stable functionality for longer tests |-->
| Heating  |         electrical         |              electrical               |
| Plates   | Metal sheets (300x200 mm)  |       Metal sheets (300x200 mm)       |
| Feed     |     3D prints + sealing     |      Improved 3D prints + gasket      |
| Drainage | 3D printed sandwich system |      3D printed sandwich system       |
| Casing   |        Wooden frame        |             Wooden frame              |


![](https://hackmd.io/_uploads/r1VdijW1a.jpg)

## Development Focus

- 8 stages
- Fluid System - the most critical module
- Detailing of Feed parts to create stable flow rate
- Water proof connections, eliminate leaking

![](https://hackmd.io/_uploads/SkTR9jbJp.jpg)






## Modules 
To keep track of the combinations of modules that create strong concepts, we document design path. Maybe we even find better solutions over time.
Get inspired, grab previously unpursued concept ideas or come up with completely new ones.

See the current considerations and design choices:

![](https://hackmd.io/_uploads/SkOnIW3K3.jpg)


### Heating
#### Electrical Heating Pads 

![](https://hackmd.io/_uploads/S1A_zRct2.jpg)

### Plates
#### Aluminium metal sheets (9x)


> :bulb: 9 plates equals 8 stages, as water can only be evaporated between plates!




![](https://hackmd.io/_uploads/H11xpgiY2.jpg)
#### Covered with wick (cotton textile)
![](https://hackmd.io/_uploads/ryf_9WjFh.jpg)


### Fluid System
#### Feed
3D printed parts (PETG), sealing from silicone mat (1 mm)
![](https://hackmd.io/_uploads/ryr-6loth.jpg)

#### Drainage
3D printed parts (PETG), sealing from silicone mat (1 mm)
![](https://hackmd.io/_uploads/rybrc-sY3.jpg)

### Casing
Wooden sheet material (18 mm)
![](https://hackmd.io/_uploads/rkXMTgiYn.jpg)

Threaded rods (M6), washers and screw nuts
![](https://hackmd.io/_uploads/S19bpxjth.jpg)

{%youtube 0x6Bavvyg4U %}


## What works 
3D printed parts got more detail and improved on printing quality. Now, Feeding parts and the sealing fit better.

## Where we need you
Tiny gaps in the sealing occur at the edge areas of the wicks, resulting in slight leaks.
Drops form on the underside of the feed and run down the sides of the plates, possibly causing contamination.

:::info
## FLOW CONTROL CHALLENGE
This development challenge focuses on improving the 3D printed parts so that they fit together perfectly and create a waterproof connection.
Compression of the parts affects the flow rate of the salty water that is absorbed by the wicks.

Let's optimize 3D printed parts made from PETG and flexible filaments or even find better alternatives.
## [Take the challenge >>>](https://hackmd.io/@ShellyTurtle/B1EpfGV9n)

:::




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![](https://i.imgur.com/xTdH2JR.gif)



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