It would take much longer than half an hour to get to 500 microns through a cap tube, even worse than trying to pull through a TXV. Even 1/4" hose starts becoming restrictive at such low vacuum levels.

Just braze in a high side service valve. They're cheap and there's no way you'll get it tuned right without a high side reading.

The charge has been adjusted. Now the unit is running at 2.3A with the fan on low speed and very little frost is present. I will now need to drain the tank and fill it with cold water and again time it for temp rise to check the effiency. If the numbers are similar for temp rise while the unit was a tad over-charged we're looking at 3.6 COP. with the lower current draw.

Again I will run the numbers and report back but its extremely cool what one can do with junk!!

Randen

Are you going to use the "amp & delta-T" optimizing method you used for your heat pump?

-AC

I popped into the shop to check the temp drop on the tank still at 42 Deg C ??!! I lingered a bit and reduced the charge and checked the current and the temps. I feel a little more tweeking may be nessisary but very close. I let it run while I did the grocery shopping, 1:30 latter the temp was at 46.4 Deg C quickly running the numbers that's 2.1 COP.

The tank is being drained. I plan to ready the mounting and cover for the compressor and condenser, get the project to the finish line.

Further tuning can happen after its all together. I would say its a success.

Randen

Congratulations on a successful and well-documented project!


I think that your helical HX idea is going to be seen in a lot of other 'heat pump DHW' projects in the future.

Big cheers for perseverance!

Best,

-AC

Awesome work Randen (as always)! :thumbup:

You certainly don't NEED a data logger to do what you're doing, but I found a really cheap, simple and effective unit right HERE.


It runs 1-wire temperature sensors (successfully tested up to 70 sensors) right out of the box. You just hook up the sensor, attach the sensor to what you want to measure, turn on the unit and you are logging! Then you remove the flash card to your computer, cut and paste the data to Excel or some other spread sheet and make graphs.



I used one to monitor my Freezerator, and from some of the graphical discontinuities, I was able to identify and solve problems very quickly. In the chart above, the upper line is the sensor on the outside of the Freezerator, showing the expelled heat. on the lower chart is the inside temperature. The discontinuous curve on the bottom line was due to water dripping right on the sensor, so I put a high-tech drip shield (up side down coffee cup) over the sensor.

Technology as it should be... cheap & simple to use.

Best,

-AC

Thanks for the thoughts AC

Today had a little time to work on the "Solar Heating for the Shop" while the machines were humming. Tiding up the stainless drip and I think I'll need to add some gussets to carry the extra weight of the acrylic.

I was thinking about controlling the heat-pump water heater system. A better temp controller and delay timer in-case of a power interruption also possibly some "time of use" system for operating the system during the lower cost for electricity. 7:00 pm to 7am
I seen that Hv23t used some Omron timers etc. If anyone could suggest some control Ideas would be great.

Randen

Assuming you don't want to do custom electronics, the thermostat that was on the tank can be used. A delay timer (delay on break) is commonly available at HVAC supply stores. And a heavy duty appliance timer can be used to only run it at certain times.

The CAI controller supports logging.
 

I just picked up another CAI controller (new model) for $36 shipped.
Remote Monitor Control Temp Humidity I O Webcontrol X10RF HW Rev 2 2 2 | eBay

I'm using some free logging software on my PC right now, but will be
running the CAI controller stand-alone shortly.
If you connect it to your router, it will set it's clock using the web.
If power fails, the clock comes back to the correct date and time, almost instantly.
It can also send you emails, if per-determinted limits are hit etc.
The PLC code isn't too hard to use.

I wanted to get the new version, because it's more accurate and also
has a loader routine, so it can be updated online.
This one also has a frequency/event counter.