The Homemade Heat Pump Manifesto - Page 142

AC_Hacker · 03-20-13, 07:45 PM

Quote:

Originally Posted by Ormston

I've almost finished laying the last of the insulation ready for the underfloor heating pipework to go in this week and maybe get the floor screed down by next weekend.

I wish you luck on your floor install.

Please take lots of photos for us to see.

HERE is a good thread to post your progress on.

Best,

-AC

cbearden · 03-24-13, 01:41 PM

I was working on taking a dehumidifier apart, to get it down to the bare necessities to hack for my water to water heat pump later on.
And I noticed that there was a solenoid connected to one of the refrigerant lines.
After I got most of this unit apart, I took some pics, hoping to find something out about it. There's a screw on top of it but I was afraid to remove it in fear refrigerant might leak before I was ready to actually break into the lines per the instructions in this forum.
hopefully these pictures show what the lines on this little unit look like.
I was also curious why there are multiple cap tubes involved here.

Thanks in advance to anyone who might can shed some light on this.

marx290 · 03-24-13, 01:53 PM

Hi cbearden!

I have the very same dehumidifier. It was one of my first hacks. You might recognize some features here. That solenoid valve is a hot gas bypass I do believe. It diverts high pressure compressor discharge gas through the evaporator for defrost purposes. The screw on top just holds the coil onto the the valve. Removing it won't vent any refrigerant. It's a good idea to take the coil off before doing any heating or brazing to the system. Have fun!

Mikesolar · 03-24-13, 01:54 PM

Quote:

Originally Posted by Ormston

Thanks for the input AC

The heating degree days for this area is around 2400 average over the last 5 years.
The rest is a bit of a guess due to the house being a work in progress with some of it still being designed/drawn.
Will be approx 150 meters2 floor area over 3 floors, the existing ground floor which is having the single story extension on 3 sides, the existing first floor and the attic being converted to provide additional bedroom and office space.

At the moment we're guessing on around 7KW maximum heating load but will have a wood burner to help out when it gets really cold.

Cooling isn't really needed in the UK, maybe 2 weeks a year if we're lucky.

I've almost finished laying the last of the insulation ready for the underfloor heating pipework to go in this week and maybe get the floor screed down by next weekend.

Steve

Always plumb them in parallel. I assume they are to be complete heat pumps and you are doing all this on the water side because if it was on the refrigerant side, it is a whole other world.....

cbearden · 03-24-13, 03:31 PM

Marx290,
Awesome! Thanks for the useful info. I'll take off the coil and play around with it some more then. nice links to pics on your hack, btw. You mentioned that you recharged it with propane. Anything particular I need to watch out for in doing this with my same rig as what you have? This will be my first attempt. I still have to gather a few more pieces of equip before I can attempt this (mainly a recovery unit), but I'm gearing up for it.
Been practicing brazing on copper and such, getting ready...

cbearden · 03-24-13, 04:22 PM

so far, this is what I'm working with.
I've removed the control board and wired the compressor to run non-stop just so I can check the amp draw on it for a bit. I think the control board wasn't working right and was only keeping compressor on for about 20sec and then I had to do a power reset to get it to come back on again.
I don't know if it would be bad on the compressor to leave it on for extended periods or not, so I've only kept it on for about 5 min so far.
I was drawing about 350 watts at first, then was about 430 watts by the time 5 min passed and I shut it off.
I found the following specs online for this LG compressor
BTU/hr cooling capacity
7250
Watts cooling capacity
2125
Motor input watts
671
EER - Btu/W.hr
10.8
COP - w/w
3.16

marx290 · 03-24-13, 04:25 PM

You sound really excited cbearden. It's a lot of fun working with this stuff. I don't know your background or what kind of equipment you have, but with an old hermetic compressor you can fashion a recovery machine for cheap if you aren't worried about reusing the recovered refrigerant. I haven't built one, but there are others out there if you do a little searching. These homemade jobs probably aren't as good as the industry machines; at least you aren't venting the gas and you recover the vast majority of it. Don't know enough about it, my dehumidifiers were all leaked out when I got them.

As far as charging with propane, there are some good threads on here about that. Safety is number one. I'm sure you will use the utmost caution and care when you're working with a flammable gas.

After I installed a piercing valve so I could purge any remaining gases out of the system, I removed that hot gas bypass, fixed the leak in my system, install two access ports, I did a triple evacuation after I was pretty sure it was leak proof and charged it from a Coleman propane bottle. You'll have to find a way to adapt a propane bottle to 1/4" flare. I charged as a vapor, but I guess you should charge as liquid to avoid any non condensables that might be in the bottle.

Just be careful. Ventilate well. Make sure you purge well before doing any brazing. Have fun!

Ormston · 03-24-13, 04:39 PM

Quote:

Originally Posted by Mikesolar

Always plumb them in parallel. I assume they are to be complete heat pumps and you are doing all this on the water side because if it was on the refrigerant side, it is a whole other world.....

Yes talking about the water side(ground loop and output to buffer tank).
Going to make them stand alone heat pumps selected my a master controller switching in the appropriate sized pumps as required.
Not even had time to take apart either of the 2 units i have stored away for this.
At least the floor screed is down and drying so when i do get a heat pump together i'll have something to heat with it.
Lots of snow outside so slow progress right now.

cbearden · 03-24-13, 08:16 PM

Thank you for the info. Yes, am definitely excited about getting to work on this. Hoping that all of this work, planning, and researching will help save on our energy usage down the road.
long road still ahead. But it feels good to get started on part of this.

cbearden · 03-24-13, 08:20 PM

AC, I just wanted to take the time to say thank you for all of your hard work and being willing to put all this incredible info on here for so many people to benefit from.
If it weren't for you and so many other generous folks on here, I would have never have attempted the kind of work that I'm delving off into.

03-24-13, 01:41 PM	#1412
cbearden Helper EcoRenovator Join Date: Aug 2011 Location: AR Posts: 39 Thanks: 11 Thanked 4 Times in 2 Posts	refridgerant solenoid? I was working on taking a dehumidifier apart, to get it down to the bare necessities to hack for my water to water heat pump later on. And I noticed that there was a solenoid connected to one of the refrigerant lines. After I got most of this unit apart, I took some pics, hoping to find something out about it. There's a screw on top of it but I was afraid to remove it in fear refrigerant might leak before I was ready to actually break into the lines per the instructions in this forum. hopefully these pictures show what the lines on this little unit look like. I was also curious why there are multiple cap tubes involved here. Thanks in advance to anyone who might can shed some light on this. Attached Thumbnails

03-24-13, 01:53 PM	#1413
marx290 Vapor Compression Goon Join Date: Mar 2013 Location: Portland, OR Posts: 63 Thanks: 11 Thanked 22 Times in 11 Posts	Hi cbearden! I have the very same dehumidifier. It was one of my first hacks. You might recognize some features here. That solenoid valve is a hot gas bypass I do believe. It diverts high pressure compressor discharge gas through the evaporator for defrost purposes. The screw on top just holds the coil onto the the valve. Removing it won't vent any refrigerant. It's a good idea to take the coil off before doing any heating or brazing to the system. Have fun! __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

03-24-13, 04:22 PM	#1416
cbearden Helper EcoRenovator Join Date: Aug 2011 Location: AR Posts: 39 Thanks: 11 Thanked 4 Times in 2 Posts	de-humidifier so far, this is what I'm working with. I've removed the control board and wired the compressor to run non-stop just so I can check the amp draw on it for a bit. I think the control board wasn't working right and was only keeping compressor on for about 20sec and then I had to do a power reset to get it to come back on again. I don't know if it would be bad on the compressor to leave it on for extended periods or not, so I've only kept it on for about 5 min so far. I was drawing about 350 watts at first, then was about 430 watts by the time 5 min passed and I shut it off. I found the following specs online for this LG compressor BTU/hr cooling capacity 7250 Watts cooling capacity 2125 Motor input watts 671 EER - Btu/W.hr 10.8 COP - w/w 3.16 Attached Thumbnails

03-24-13, 04:25 PM	#1417
marx290 Vapor Compression Goon Join Date: Mar 2013 Location: Portland, OR Posts: 63 Thanks: 11 Thanked 22 Times in 11 Posts	You sound really excited cbearden. It's a lot of fun working with this stuff. I don't know your background or what kind of equipment you have, but with an old hermetic compressor you can fashion a recovery machine for cheap if you aren't worried about reusing the recovered refrigerant. I haven't built one, but there are others out there if you do a little searching. These homemade jobs probably aren't as good as the industry machines; at least you aren't venting the gas and you recover the vast majority of it. Don't know enough about it, my dehumidifiers were all leaked out when I got them. As far as charging with propane, there are some good threads on here about that. Safety is number one. I'm sure you will use the utmost caution and care when you're working with a flammable gas. After I installed a piercing valve so I could purge any remaining gases out of the system, I removed that hot gas bypass, fixed the leak in my system, install two access ports, I did a triple evacuation after I was pretty sure it was leak proof and charged it from a Coleman propane bottle. You'll have to find a way to adapt a propane bottle to 1/4" flare. I charged as a vapor, but I guess you should charge as liquid to avoid any non condensables that might be in the bottle. Just be careful. Ventilate well. Make sure you purge well before doing any brazing. Have fun! __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

03-24-13, 03:31 PM	#1415
cbearden Helper EcoRenovator Join Date: Aug 2011 Location: AR Posts: 39 Thanks: 11 Thanked 4 Times in 2 Posts	Marx290, Awesome! Thanks for the useful info. I'll take off the coil and play around with it some more then. nice links to pics on your hack, btw. You mentioned that you recharged it with propane. Anything particular I need to watch out for in doing this with my same rig as what you have? This will be my first attempt. I still have to gather a few more pieces of equip before I can attempt this (mainly a recovery unit), but I'm gearing up for it. Been practicing brazing on copper and such, getting ready...

03-24-13, 08:16 PM	#1419
cbearden Helper EcoRenovator Join Date: Aug 2011 Location: AR Posts: 39 Thanks: 11 Thanked 4 Times in 2 Posts	Thank you for the info. Yes, am definitely excited about getting to work on this. Hoping that all of this work, planning, and researching will help save on our energy usage down the road. long road still ahead. But it feels good to get started on part of this.

03-24-13, 08:20 PM	#1420
cbearden Helper EcoRenovator Join Date: Aug 2011 Location: AR Posts: 39 Thanks: 11 Thanked 4 Times in 2 Posts	AC, I just wanted to take the time to say thank you for all of your hard work and being willing to put all this incredible info on here for so many people to benefit from. If it weren't for you and so many other generous folks on here, I would have never have attempted the kind of work that I'm delving off into.