LexiMechanic & PWMaster
Hey Lexi, how about we dive into designing the ultimate cooling loop for an electric kettle? I've got a few airflow curves and I could use a sharp editor’s eye on the specs. What do you think?
Sounds like a fun project. Send me the airflow curves and the key parameters you’re balancing—temperature rise, pressure drop, fluid choice, and any safety margins you’ve set. I’ll sift through the numbers, spot any inconsistencies, and suggest tightening the tolerances where you can keep the loop efficient without sacrificing reliability. Just hit me with the specs and we’ll get the loop humming in no time.
Sure thing. Here are the core numbers for the kettle loop: target max temp rise 30 °C, peak inlet temp 90 °C, inlet pressure 1.2 bar absolute, desired pressure drop across the heat exchanger 0.25 bar, flow rate 0.2 L/s, fluid is 30 % ethylene glycol in water for 50 °C operating temp, safety margin on pressure 15 %, safety margin on temp 10 %. The fan curves I’ve plotted show 200 CFM at 1.2 bar and 150 CFM at 0.8 bar. Let me know if any of those numbers look off or if you want tighter tolerances.
Your numbers line up mostly, but a few things deserve a second look. The inlet is already at 90 °C, and you’re adding a 30 °C rise, so the hot spot hits 120 °C. That’s a lot for a 30 % ethylene‑glycol mix—its viscosity climbs fast, and you’ll be pushing the boiling point of the mixture down a bit. If you’re targeting a 50 °C operating point, the inlet temp should be closer to that, or you’ll need to re‑evaluate the mixture ratio.
The flow rate you’re asking for—0.2 L/s, which is about 28 CFM— is far below the fan’s 200 CFM at 1.2 bar. That means the fan is over‑specified; you’ll have a very low pressure drop and a lot of wasted energy. Either cut the fan size or raise the desired pressure drop.
The safety margins look reasonable: 15 % on 1.2 bar gives a maximum of about 1.38 bar, and 10 % on a 30 °C rise gives a ceiling of 33 °C. Just make sure the heat exchanger and the fluid can comfortably handle the 120 °C hotspot without cracking. Tightening the inlet temperature and adjusting the fluid concentration should bring the loop into a cleaner, more efficient regime.