Timeline for Aluminum or Copper, which one is better to control and maintain the temperature?
Current License: CC BY-SA 4.0
15 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| S Aug 12, 2021 at 17:45 | history | edited | Pete W | CC BY-SA 4.0 |
Moved comments that belong to the answer. The answer is explained for the better understanding, thus better acceptance.
|
| S Aug 12, 2021 at 17:45 | history | suggested | jay | CC BY-SA 4.0 |
Moved comments that belong to the answer. The answer is explained for the better understanding, thus better acceptance.
|
| Aug 12, 2021 at 17:05 | vote | accept | jay | ||
| Aug 12, 2021 at 17:05 | review | Suggested edits | |||
| S Aug 12, 2021 at 17:45 | |||||
| Aug 12, 2021 at 16:54 | comment | added | jay | I hear you, Pete! Finally I see we are talking about the same and agreeable idea based on the fundamentals you answered. And, I see how the mechanical engineer concluded to use copper "pipe" from "For 2, if you are building from pipe/tube, there are a finite number of specific options wall thickness". Now, I am understanding the mechanical engineer here better. I will copy both of yours and mine, edit, and accept, will try. You may re-edit it, since that belongs to you. | |
| Aug 12, 2021 at 16:28 | comment | added | Pete W | yes for 1. For 2, if you are building from pipe/tube, there are a finite number of specific options wall thickness. So just make a table of the bulk heat capacity in J/K for the options you have given mechanical constraints. That will inform the remaining analysis, but is not necessarily the performance limiting factor. Often not. Regarding effect of controller, it depends on placement of heater and sensor. If you are not sure what you are doing, then a big thermal mass with a slow response might actually be more practical than something light and aggressively tuned. | |
| Aug 12, 2021 at 16:09 | comment | added | jay | Once you have agreed, I would try (not sure if I have the privilege in this site) to include that comment in your answer, and then accept your answer. | |
| Aug 12, 2021 at 16:06 | comment | added | jay | See if I understand it correct: 1) If the volume of the pipe was the same, aluminum would be more effective delivering the heat from one end to another. If the weight of the pipe was the same, copper would be more effective. 2) Since, the length/shape of the pipe is constrained by the mechanical structure, the volume matters more. 3) Thus, I would choose aluminum pipe, if I have good trust in my controller. 4) I would choose copper pipe for less influence from disturbance (ex. from ambient), if the performance of the controller was excluded. | |
| Aug 7, 2021 at 17:47 | comment | added | jay | Deep thoughts! I can agree all that. I will put some good efforts to understand more. Though, I cannot say which one to choose definitely yet. Meantime, I now understand why some of my "correct" answers (in other threads) were not accepted, no offense. Problem might be at the questioner's. :) | |
| Aug 7, 2021 at 17:22 | comment | added | Pete W | depends on whether thermal-load disturbances are more at the location being controlled (then more thermal mass may in some cases help stabilize), or more at the location(s) with the heater/cooler (then more thermal mass just adds unwanted delay in the loop) | |
| Aug 7, 2021 at 17:16 | history | edited | Pete W | CC BY-SA 4.0 |
added 89 characters in body
|
| Aug 7, 2021 at 17:12 | comment | added | Pete W | "control performance" near steady state, i.e. when the heat flux is not maxed out, will depend on how quickly change in heat flux at the heating or cooling location(s), is propagated through the material. It's probably not fair to generalize further, without considering thermal load and geometry, including placement of sensor(s). It is possible more thermal mass would be helpful for that. | |
| Aug 7, 2021 at 17:05 | comment | added | Pete W | Electric heat will have some power limit, i.e. max heat flux is constant. (Can locally reach very high temperatures without too much trouble.) With that constraint, peak dT/dt is roughly determined thermal mass of material. Cooling with a coolant has (sloppy approximation) constant T, so max heat flux proportional to temp diff and thermal conductivity of material. In both cases, best ramp time depends (roughly) on max heat flux, and total thermal mass of material. For fixed geometry, thermal mass depends on volumetric heat capacity. | |
| Aug 7, 2021 at 16:27 | comment | added | jay | It started shaping some base approach in my thoughts. "volumetric_heat = density * specific_heat" gives some insights. I will study more to understand. We are not too concerned about cooling, though it will eventually be something to consider. Cooling uses a fan at the moment. Could you please add a little more explanation in you answer text, why the properties for "max heating ramp" are less effective to "steady state" target? Can it be a different story, if the controller can be tuned well? Wouldn't the controller prefer faster response time anyway? | |
| Aug 7, 2021 at 15:17 | history | answered | Pete W | CC BY-SA 4.0 |