Initial Working Principle
We initially envisioned a water bottle that utilizes both the Venturi effect and evaporative air cooling.
Our decision to test out the Venturi effect was inspired by a Bangladeshi air cooler made from plastic bottles, which uses no electricity. The Venturi effect refers to an increase in velocity of fluid flow, and a corresponding drop in static pressure, when a fluid traveling through a pipe encounters a constriction of the pipe.
A water pump and honeycomb media will be used for evaporative cooling. The extensive surface area of honeycomb media should permit ample water saturation for evaporative cooling.
The bottle will require a specially designed cap for the user to drink water from, while the electrical components must be safely isolated from the water container. The water container should also be coated with a food-safe material.
Images | Left: Schematic showing initial concept of air cooler bottle. | Right: “Honeycomb USHA Air Coolers.” https://www.ushaaircoolers.com/ecocool-honeycomb
Sources
C. DiStasio, “This amazing zero energy Bangladeshi air cooler is made from plastic bottles and uses no electricity,” Inhabitat – Green Design, Innovation, Architecture, Green Building | Green Design & Innovation for a Better World, Aug. 2016, [Online]. Available: https://inhabitat.com/this-amazing-bangladeshi-air-cooler-is-made-from-plastic-bottles-and-uses-no-electricity/
A. Felföldi, “What Is the Venturi Effect?,” SimScale, Jun. 01, 2023. [Online]. Available: https://www.simscale.com/blog/what-is-venturi-effect/
First Phase
CAD model of Air Cooler Bottle
Assembly of 3D-Printed Prototype
Images | Left: Assembled prototype with basic electronics. | Right: Partially assembled prototype showing fan mounted on DC motor.
We noticed that the air is deflected tangentially towards the right, due to its turbulent circular flow in the bottle, which agrees with flow simulations. Hence, we decided that the outlet should be off-centered in subsequent prototypes to capture most of the air flow.
Images | Left: Isometric view of flow simulation showing turbulent circular flow in assembled prototype. | Right: Top view of flow simulation showing turbulent circular flow in assembled prototype.
Second Phase
CAD model of Air Cooler Bottle
Upon recognising that the ultrasonic piezoelectric transducers do not consume a lot of water to disperse mist, we have made the inner bottle smaller, which will also boost airflow. We have also modified the base of the outer bottle to accommodate the placement of silica gel cages to dry the incoming air.
Third Phase
Final CAD Model of Air Cooler Bottle
We have added four holders on each of the four sides of the inner and outer bottles to radially position the evaporative filters.
Initially, we faced issues with ensuring proper fitting of the bottle cap threads, so we tried designing a locking mechanism to secure the cap and two bottles. However, we eventually discarded this mechanism after we successfully printing well-fitted bottle cap threads after some iterations.
To accommodate the small size of the DC brushed and coreless motor we are using, we have reduced the height of the bottle cap to maximise airflow.
An electronic base was added and two compartments for electronics are also fitted into the design.