On Wed, Jan 17, 2024 at 12:07:42AM -0500, Glenn McGurrin via NANOG wrote:
Free air cooling loops maybe? (Not direct free air cooling with air exchange, the version with something much like an air handler outside with a coil and an fan running cold outside air over the coil with the water/glycol that would normally be the loop off of the chiller) the primary use of them is cost savings by using less energy to cool when it's fairly cold out, but it can also prevent low temperature issues on compressors by not running them when it's cold. I'd expect it would not require the same sort of facade changes as it could be on the roof and depending only need water/glycol lines into the space, depending on cooling tower vs air cooled and chiller location it could also potentially use the same piping (which I think is the traditional use).
You're looking for these: https://en.wikipedia.org/wiki/Thermal_wheel Basically, an aluminum honeycomb wheel. One half of its housing is an air duct "outside" while the other half is an air duct that's "inside." Cold outside air blows through the straws and cools the metal. Wheel rotates slowly. That straw is now "inside." Inside air blows through it and deposits heat onto the metal. Turn turn turn. A surprisingly effective way to lower heating/cooling costs. Basically "free," as you just need to turn it on the bearing. Do you get deposits in the comb? Yes, if you don't filter properly. Do you get condensation in the comb? Yeah. Treat it with desiccants. -- . ___ ___ . . ___ . \ / |\ |\ \ . _\_ /__ |-\ |-\ \__