EcoRenovator - View Single Post - Dxgshpwh (ground source heat pump water heater)

AC_Hacker · 06-08-15, 04:18 PM

MEMPHIS91,

I'm just thrashing around here, thinking of possible problems & approaches...

Whatever happened to the original cap tube? Was it damaged when you dismantled the machine? There is a possibility that you might be able to get things going with it... if it's still intact.

BTW, when you were brazing, did you use some kind of purging gas, so the tiny black flakes did not form? Because if you didn't, just one flake could be a problem.

Also, most of the attention is being paid to the compressor balance issue, when the problem might be elsewhere.

* * *

So, I was considering this thing from a 'black box' point of view. You have three black boxes: BOX #1: ground loop box, BOX #2: compressor box, and BOX #3:water heater box.

Unfortunately we don't have any way to determine if the mass flow is what it should be for this system... right?

BOX #3
The water heater box has been proven to be a viable concept, and several EcoRenovators have use this configuration, first time out. So the concept is sound, but do you know for sure that your implementation is good. The only problem I can think of would be a kinked tube that you did not notice. If all else fails, you could test this by disconnecting it from your system and blowing compresses air through it to see if a reasonable flow is happening. This is really the least likely failure, but as a last resort, you might test this.

BOX #1
Another 'black box' is the ground loop. Here, you are in new territory, since there haven't been any EcoRenovators, or any other DIY hacker to try this (with the exception of the very first heat pump ever made, and your general configuration, of burying tubes in the ground, was what he did). So we do have second-hand confirmation that this can be a viable configuration. Then the question is of implementation. There could be a possibility of a kink. There could also be a possibility of an oil-flooded tube, that is impacting your performance. If you need to, you could test this in the same way that you could test the tubing in your water tank... disconnect from the compressor and blow air through it, and assess if it has reasonable flow.

There is another possibility of the ground loop, and that would be that your ground loop is not extracting heat from the ground fast enough to supply to the tank (via the compressor). I know that the ground gives up its heat slowly, and that is why a 200 foot deep hole is required to extract 12,000 BTU/hr (in Oregon, where the temp is 52F). As I recall, you have a 5000 BTU compressor. So if the Oregon hole requirements work for MS (not the best assumption, MS should be better yield), then your hole should be:

Depth = 200ft * (5000 / 12000) = around 83 ft deep.

It is possible that the depth, or number of holes is insufficient. I have made some really flakey assumptions here, but I think that I'm generally headed in the right direction.

BOX #2
Box #2 is the compressor box. I have been following the analysis of the compressor's role in the problems you are having, and I would have to say that I am truly impressed by the help that has been flowing into this thread, to try to assist you in achieving success. It is really shows the very best of our community, when we come together to solve a problem.

And I have to admit that the caliber of expertise is well over my head, and I have nothing to add that could be helpful.

Best,

-AC

06-08-15, 04:18 PM	#115
AC_Hacker Supreme EcoRenovator Join Date: Mar 2009 Location: Portland, OR Posts: 4,004 Thanks: 303 Thanked 723 Times in 534 Posts	MEMPHIS91, I'm just thrashing around here, thinking of possible problems & approaches... Whatever happened to the original cap tube? Was it damaged when you dismantled the machine? There is a possibility that you might be able to get things going with it... if it's still intact. BTW, when you were brazing, did you use some kind of purging gas, so the tiny black flakes did not form? Because if you didn't, just one flake could be a problem. Also, most of the attention is being paid to the compressor balance issue, when the problem might be elsewhere. * * * So, I was considering this thing from a 'black box' point of view. You have three black boxes: BOX #1: ground loop box, BOX #2: compressor box, and BOX #3:water heater box. Unfortunately we don't have any way to determine if the mass flow is what it should be for this system... right? BOX #3 The water heater box has been proven to be a viable concept, and several EcoRenovators have use this configuration, first time out. So the concept is sound, but do you know for sure that your implementation is good. The only problem I can think of would be a kinked tube that you did not notice. If all else fails, you could test this by disconnecting it from your system and blowing compresses air through it to see if a reasonable flow is happening. This is really the least likely failure, but as a last resort, you might test this. BOX #1 Another 'black box' is the ground loop. Here, you are in new territory, since there haven't been any EcoRenovators, or any other DIY hacker to try this (with the exception of the very first heat pump ever made, and your general configuration, of burying tubes in the ground, was what he did). So we do have second-hand confirmation that this can be a viable configuration. Then the question is of implementation. There could be a possibility of a kink. There could also be a possibility of an oil-flooded tube, that is impacting your performance. If you need to, you could test this in the same way that you could test the tubing in your water tank... disconnect from the compressor and blow air through it, and assess if it has reasonable flow. There is another possibility of the ground loop, and that would be that your ground loop is not extracting heat from the ground fast enough to supply to the tank (via the compressor). I know that the ground gives up its heat slowly, and that is why a 200 foot deep hole is required to extract 12,000 BTU/hr (in Oregon, where the temp is 52F). As I recall, you have a 5000 BTU compressor. So if the Oregon hole requirements work for MS (not the best assumption, MS should be better yield), then your hole should be: Depth = 200ft * (5000 / 12000) = around 83 ft deep. It is possible that the depth, or number of holes is insufficient. I have made some really flakey assumptions here, but I think that I'm generally headed in the right direction. BOX #2 Box #2 is the compressor box. I have been following the analysis of the compressor's role in the problems you are having, and I would have to say that I am truly impressed by the help that has been flowing into this thread, to try to assist you in achieving success. It is really shows the very best of our community, when we come together to solve a problem. And I have to admit that the caliber of expertise is well over my head, and I have nothing to add that could be helpful. Best, -AC __________________ I'm not an HVAC technician. In fact, I'm barely even a hacker... Last edited by AC_Hacker; 06-10-15 at 09:18 AM..