Open Source Solar Water Heater
From Open Source Ecology
Basics
- A Device that uses Solar Thermal to heat water
- Can be used from cold to near boiling (see Open Source Solar Steam Generator ) for water to Wet Steam, and Open Source Steam Superheater for Wet Steam to Dry Steam
- There are many ways of doing this but this page will focus on pancake coil type designs, see Open Source Thermosyphon for thermosyphon designs
- Pancake works well, a tube with modular screw in ports for long plastic tube runs is better for high flow
- Need to look into if these can be grouped for boiling temperatures (this may lead to Steam Hammer and/or overpressure explosions, but perhaps with the right precautions (Steam traps, overpressure valves. etc)
- Direct systems can be used for pool/utility water, for potable water, indirect may be better
- Hard part seems to be storage systems for the pressurised, potable water
- Some way to make a sort of "on demand hot water" for central hot warer, via indirect heating?
- If not simplest market is pool heating
Industry Standards
Plastic Tube Panel
Existing Open Source Designs
Plastic Tube Coil
Minimum Viable Product
- Should be able to reach near boiling (~80C is what most existing designs could reach in one stage)
- Should be a small flat square (less than 1m^2 wide, and less than 5 cm deep?)
- Should use standard hose fittings for both the "in" and the "out"
- Optional temperature probes
- perhaps have a thicker and slightly wider model with insulation
Basic Design
Plastic Tube Coil
Box
- A wood or metal box
- Optional insulation
Backplate
- =Sheet metal
- make reflective or dark as well?
Coil
- Standard OTS refrigeration coil, or custom bent tubing
- Has the standard fittings at each end
Insulation
- Foam and/or fiber for the main areas
- Glass and air/vacuum gap above coil, or would the walls and cost make it not worth it?
Temperature Probes
- Attach right above the hose adapters
- Wires go where?
Paint
- Most likely standard black paint, but the darker, the better
- Not 100% needed, but is a cheap way to increase absorbtion
Heat Exchanger?
BOM
- ~1m Sheet Metal (what metal?)
- Fiberglass insulation
- Foam Insulation
- Either copper piping, or an OTS refrigeration coil
- Fittings
- Optional temperature sensors
- Perhaps Wood or Plastic Exterior
Plastic Tube Panel
Rigid High Temp PVC Pipe
- Used for the top and bottom pipes (ie feed and return)
Flexible (Black) High Temp Hosing
- Used to get up and down from the panel, and for the panel's "runs"
Attachment Points
- Either OTS fittings, or some custom solution
- Screw in/otherwise attach to the top and bottom pvc pipes, holding the runs in place, and connecting them to the system
- Modular, as as many as wanted can be added to a cut section of HT PVC Pipe
Control Box
- Arduino and/or Rpi
- Takes Sensor Data, and IO Settings in
- Controls the Pump
Temperature Probe
- 1 at each end of the collector panel (two total)
- 1 in the working fluid tank
- 1 at each end of the tank (ie to and from panel)
Pump
- Small electric pump (calculate head needed)
Working Fluid
- Most likely some sort of oil (higher viscosity, but will not freeze?
- Also stores heat better
Internal Links
External Links
