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SimplifyAndAddCoffee · 04-06-2023, 05:20 PM

This seems like such a simple concept that it never sat right with me that there aren't any really good solutions out there in the wild that I've seen or been able to find.

EDIT: I know of those cheap window units that are all over the internet, but they're absolute garbage and on top of being poorly manufactured, they're not well designed and not a good solution at all.

My modest proposal:

Use one or two small fans with efficient ducting to draw clean, cool air into the cabin, and exhaust hot air out. Have them run only when a sufficient temperature delta exists between the cabin and outdoors, and remain sealed off the rest of the time to prevent energy loss. Power them using either their own PV circuit, or from the vehicle's 12v system, with a PV and BMS to keep it topped up and prevent over-discharging.

The Materials:

2x high-static-pressure 120mm 12v PWM fans from Noctua
3D printed static turbines, louvers, and ducting (will design parametric library in OpenSCAD
MERV12/13 furnace air filter
Arduino or similar microcontroller
two remote temperature probes/thermistors
Some discrete electronics components
5-watt 12-volt dash-top solar panel
possibly a clutch of 18650 cells and BMS
Drill/hole saw/sawzall

The plan:

Cut hole size of fan on lower bulkhead behind the front seats, install fan to pull air in.
Route ducting in from the underside of the car, with a slim enclosure for a small furnace air filter.
3d print slim ducting to run from an inlet just below the headliner, down the passenger B pillar, and out the bottom of the car, using another fan.
Install inlet/outlet louvers that only open when the fans are running
use remote temp probes with microcontroller to power the fans on conditionally when the inside temp reads 10 degrees higher than the outside temp, and the vehicle is off and stationary
install solar charger for 12v system (was going to do that anyway...) and low voltage cutoff to fan system, OR, isolated system with 18650 batteries and solar charger/BMS.

Thoughts? ideas? Search didn't turn anything up, but has anyone done something like this before?

04-06-2023, 05:20 PM	#1 (permalink)
SimplifyAndAddCoffee EcoModding Lurker Join Date: Apr 2023 Location: California Posts: 7 Thanks: 0 Thanked 3 Times in 2 Posts	Designing a better (Best?) car cooling solution for when parked in the sun This seems like such a simple concept that it never sat right with me that there aren't any really good solutions out there in the wild that I've seen or been able to find. EDIT: I know of those cheap window units that are all over the internet, but they're absolute garbage and on top of being poorly manufactured, they're not well designed and not a good solution at all. My modest proposal: Use one or two small fans with efficient ducting to draw clean, cool air into the cabin, and exhaust hot air out. Have them run only when a sufficient temperature delta exists between the cabin and outdoors, and remain sealed off the rest of the time to prevent energy loss. Power them using either their own PV circuit, or from the vehicle's 12v system, with a PV and BMS to keep it topped up and prevent over-discharging. The Materials: 2x high-static-pressure 120mm 12v PWM fans from Noctua 3D printed static turbines, louvers, and ducting (will design parametric library in OpenSCAD MERV12/13 furnace air filter Arduino or similar microcontroller two remote temperature probes/thermistors Some discrete electronics components 5-watt 12-volt dash-top solar panel possibly a clutch of 18650 cells and BMS Drill/hole saw/sawzall The plan: Cut hole size of fan on lower bulkhead behind the front seats, install fan to pull air in. Route ducting in from the underside of the car, with a slim enclosure for a small furnace air filter. 3d print slim ducting to run from an inlet just below the headliner, down the passenger B pillar, and out the bottom of the car, using another fan. Install inlet/outlet louvers that only open when the fans are running use remote temp probes with microcontroller to power the fans on conditionally when the inside temp reads 10 degrees higher than the outside temp, and the vehicle is off and stationary install solar charger for 12v system (was going to do that anyway...) and low voltage cutoff to fan system, OR, isolated system with 18650 batteries and solar charger/BMS. Thoughts? ideas? Search didn't turn anything up, but has anyone done something like this before? Last edited by SimplifyAndAddCoffee; 04-06-2023 at 08:31 PM..