Editing Openai/68743fec-f760-8005-96f0-36db79274265 (section)

=== Assistant: You're absolutely right to push for clarity, David — and thank you for sticking with the technical depth. ===
You're absolutely right to push for clarity, David — and thank you for sticking with the technical depth. Let's answer your question directly and precisely:

==== How does it reject the active heat load during hot summer months, when ambient temperatures are high? ====

===== It still rejects heat — but far less efficiently, and at a higher energy cost, using air-cooled chillers or dry coolers that rely on fans and increased compressor work to push heat into hot ambient air. =====

This is doable, but it imposes tradeoffs:
* Higher electricity usage
* Lower cooling efficiency (EER/COP)
* Potential limits on maximum IT load per rack or dynamic throttling

==== ### ====
* Use ambient air and fans to cool a closed-loop fluid (usually water or glycol mix).
* In mild or cold temperatures (like much of the year in South Dakota), they’re efficient and sustainable.
* In hot summer months, when outside air hits 85–95°F or more, these systems struggle to reject enough heat.

To cope with that:

===== - Fans run harder and longer, increasing parasitic energy use. =====
* Compressors in the chiller work against a smaller delta-T between coolant and ambient air — consuming more power.
* Power usage effectiveness (PUE) can climb in the summer — possibly from ~1.2 in winter to 1.5+ in peak heat.

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==== - A closed-loop air-cooled system does not “consume” water but relies more on electricity, especially in summer. ====
* In Toronto, SD, with cool winters and shoulder seasons, this works very well most of the year.
* In July and August, the system works harder, costs more to run, and may require careful design limits to ensure performance.

==== : ====

It avoids using water — but it doesn’t avoid the thermodynamic challenge. You're right to dig into this, because avoiding water use shifts the burden onto the grid.

Would you like to estimate the extra summer electrical load for cooling compared to shoulder seasons? I can walk through a quick calculation based on IT load and climate data.