Personal

Compact Desalination Kit

Personal Project · January 2026

A compact thermal desalination device built from copper tubing and a stainless-steel bottle, recovering approximately 55% of its input water as liquid condensate.

Compact desalination kit assembled from a stainless-steel bottle and copper tubing — Completed compact desalination kit with its stainless-steel boiling vessel and coiled copper condenser.

Overview

Designed and assembled a compact proof-of-concept desalination kit that boils saltwater and routes the resulting vapor through a coiled copper condenser. Testing on a kitchen stove showed that approximately 55% of the initial water mass was recovered as liquid output.

My Role

Developed the device layout, formed and fitted the copper tubing, modified and sealed the bottle cap, assembled the required fittings, and conducted the initial mass-based recovery test.

Project Overview

This project explored whether a simple thermal desalination device could be made compact enough to store with my camping equipment. The system uses a stainless-steel bottle as the boiling vessel and a length of copper tubing as the vapor path and condenser. When saltwater is heated, water vapor travels through the tubing, cools, and condenses into a separate collection container whilst the dissolved salts remain in the bottle.

Construction

The copper tubing was cut to length and carefully wound around the stainless-steel bottle to create a compact condenser. I drilled through the bottle cap, passed the tubing through the opening, and sealed the joint with lead-free solder to limit vapor leakage. Additional fittings were then installed to complete the assembly and provide a controlled outlet for the condensed water.

Modified stainless-steel bottle cap with sealed copper tubing — Copper tubing passed through the modified bottle cap and sealed with lead-free solder.

Compact copper condenser wrapped around the stainless-steel bottle — Copper tubing wound around the bottle to illustrate the compact assembly.

Experimental Testing

For initial testing, I heated a measured quantity of water in the bottle using a kitchen stove and collected the liquid discharged from the condenser. Comparing the input and output masses showed that approximately 55% of the starting water was recovered as liquid. The remaining mass was primarily lost as uncollected water vapor through incomplete condensation or leakage from the system. I found that placing a damp cloth around the coils increased the amount of liquid condensed.

Liquid-water recovery

~55% by mass

Heat source

Kitchen stove

Testing the compact desalination kit and collecting water from the copper condenser.

Design Results

The completed system successfully demonstrated the basic desalination process in a compact, portable assembly. Vapor generated in the stainless-steel bottle traveled through the copper coil and condensed into a separate liquid output. Although the 55% recovery rate leaves considerable room for improvement, the test confirmed that the device can perform its intended function at a basic level.

Liquid-water recovery

~55% by mass

Boiling vessel

Stainless-steel bottle

Condenser

Coiled copper tubing

Heat source used during testing

Kitchen stove

Reflection & Next Steps

This was a straightforward and enjoyable project that turned a small group of common components into a functioning thermal separation system. I do not anticipate needing it often, but its compact size made it an easy addition to my camping equipment. A future revision could improve the seal within the elbow connector, extend or actively cool the condenser, and better insulate the boiling vessel to increase liquid recovery and reduce energy loss.