Ah. OK. If you’re getting 37C with a fan & heatsinks then you don’t want to run it without them.
The Pi4 clocks down after a few minutes, when it is getting to hot and that should be fast enough for the simple tasks he does.
Unless you mount the case with the pi4 inside the heat chamber it does not matter. I just added the heat sinks onto mine, but no fan at all. Even the Pi1 inside the heat chamber has no fan.
I don’t EVER want a CPU throttling down from overheating. For me, that is a cardinal sin, and deserves total revocation of the owner’s geek creds. It’s a sure sign of poor design & poor execution. It should just not happen. Now, if adding heatsinks will keep the temp below 50C then that should be OK. Otherwise, add a fan or provide some other means of cooling.
It doesn’t start to throttle the CPU until it reaches 80c on the PI 4
When the Pi 4 heats up beyond 80°C (176°F), the CPU is throttled to reduce the temperature and a half-full red thermometer appears on the display, if one is connected. If the temperature goes up beyond 85, the GPU, which now supports dual monitors and 4K resolution, will be throttled as well
Which is in line with many other CPU makes & models. That said, I just don’t accept temps over 50C on my computers. I do what it takes to get CPU temps below that. My current i7 CPU runs a number of torture tests below 40C. It typically runs around 30C.
GPUs are a bit different. They do tend to run hotter before they throttle down but, even there, I don’t accept temps above 75C and I work really hard to get them below 65C.
I agree the cooler they run the longer they will last. Yet another reason i like to over power my computer equipment.
Yes, AND the more stable they run.
The question is why to add a computer that is overpowered, creating more heat, needs more energy and is more expensive, for a task a cheaper, less power consuming and in general cooler system can handle?
A pi3 has four cores, too. The Pi2 I think has two like the Pi1. So using the Pi3 gives you the very same experience at a lower price point and with less power consumption.
i have a pi 3 and after putting both on my power meter i can tell you they pull the same power.
On idle maybe, but under load you cannot even use the same power supply, as the Pi4 needs more juice. It requires 2.5A as minimum if I recall right. If you want to use the usb 3 ports with passive devices this also increases the potential power requirement as in theory 1A per port can be sucked.
The Pi1 works barely with an 1A power supply. The Pi3 here works with a 1.5A power supply, but already gives power warnings (color block in to right corner), which I disabled.
Since I use ATX power supplies on my 3d printers I have just 2A standby power, which seems to be fine for a Pi3 at least. However I would not risk blowing a cheap wall plug using a Pi.
Since the Pi 4 would be running at a lower cycle rate, I suspect it would use the same or less power under the same load as a Pi 3. IOW, do exactly the same print, to the same printer, with both Pi’s and I suspect there wouldn’t be much difference in power consumption.
And let’s not forget that the amount of power a Pi, either 3 or 4, would use while printing is nothing compared to the power used by the printer itself. After all, the printer has 2 electric heating elements. Since the Pi’s use the same power while idle, the power differential must be negligible.
Depends on how well PID tuned your printer is. I did some measurements when having the TronXY on my workbench recently.
ATX Power Supply, Raspberry Pi2, a crappy China board plus steppers and heaters. During heating phase it was around 60W dropping to around 20-30. When both heaters were heating, which rarely happens and only for a very short time, it spiked to around 80W for a few seconds.
Of course the initial heating is the critical element, where all the power is blasted, but - at least for me - this happens only once. Afterwards I chain the prints to avoid any reheating. My printers are running 24/7 for three days now printing parts for the giant clock and I interrupt them only to drop parts for other projects inbetween. 
Keeping and holding the temperature is not a big deal. Especially when your heat bed is properly insulated on the bottom. The insulation not only prevents the underside from cooling. The heating usually takes place on the under side, so the insulation redirects the power to the top of the bed. To get the old ANet A8 12V Heat bed to 80°C it takes around 8-10 minutes. Without the insulation it took more than twice as long. So a lot of power is saved on that end already.
My printer doesn’t run that much. In fact it’s been nearly 2 days since it was powered on. I’m printing some pieces for a new forklift bed reinforcement system that uses threaded rod & turnbuckle nuts to put upward pressure on the bed, so it can’t deflect downward so easily. Not as good as dual Z axes, but it should be better than original.
I usually stack prints inside OctoPrint, so when I start printing I can print a while. The giant clock is by far the biggest project here, since the GeitPrinter, where prototyping the Z gantry sometimes took 40 hours to reprint all parts.
I change filaments too often for that.
And? I need to remove the print and swap the filament if needed, while OctoPrint is keeping the heat up. The filament swap takes about 20 seconds, tops. Sometimes it takes longer to get the print off the build plate. The 7 segment digits of the giant clock need a filament change before each print, as the front is white and the shelf is wood color.
Oh. I thought you were implying you stack up prints in OctoPrint so a new print can start right after 1 finishes. Although, I was wondering how you space out the prints so they don’t get in each other’s way.
Heh, no. 
I usually not even put more than one object on the build plate, even if they are just 20 minute prints each. I just sort them, so the longer prints are at night, so I don´t have to get up to remove parts and start the next print. Being able to control the printer from a phone/tablet is quite handy as all files are already there you just need to start a new job. No slicing and uploading involved.
My printing style would be a nice usecase for a belt printer. You just dump all 40 files for a project into the printer and it prints one after the other. When one print fails it does not matter, as it does not effect the other prints. You just need to reprint the failed prints afterwards. Well, without dual color printing by swapping filament. That would be hard to achieve with such type printers.
For the giant clock I only print the base structure and the led plate in tripples on the plate, as the overall quality does not matter as long as the structure is done. If parts fuse together or a bridging fails I simply cut the correct model out and done. Failures like failed bridging can be fixed with acetone. Well, not happened for the first prints and not expected eater as my printers are usually very reliable.
I could certainly see it being very useful for conveyor belt printers.
Like the CR-30? I’ve heard that Blackbelt Cura slicer is the only one that supports that type of 45 degree printing. And it’s very buggy. Supports for that kind of printer would be very unusual i would think