Propane (R-290) for heat pumps? - Page 20

marx290 · 03-10-13, 09:07 PM

Quote:

Originally Posted by Piwoslaw

What if an ASHP was to draw air from a solar hot air collector? Has anyone tried this?

As long as there is no air flow restriction then the slightly higher air temp would raise the HP's COP, while at worst it would be the same as with no collector.

The collector could also have a bit of thermal mass, which would store some heat if the sun is shining while the HP is off.

I think it's a great idea. I was planning on trying it two years ago with a small geodesic dome covered in PE. I was going to insulate the back or at least use a reflective material and store a couple of black plastic barrels towards the back with water or brine in them to absorb daytime rays to emit at night. Ventilation control in the "greenhouse" would be crucial I suppose. I'd love to know if anyone has ever tried something like this.

Thepprof · 03-11-13, 05:37 AM

Years ago I was putting a roof on a building and had several pieces of corrogated galvanized roofing left over. approximately 3 ft x 6 ft. I framed the metal with wood with a 1 in thick foam insulation back approximately 1 inch from the back of the metal and covered the front with clear plastic. The metal was painted black. I went inside to answer the telephone and a few minutes later came back to the project. the metal was so hot that it burnt my hand when I picked it up to reposition it. I leaned it against my house under a bed room window in such a way that opening the window let the heat in our out. It really kicked butt on sunny days...

marx290 · 03-11-13, 10:41 AM

I lived in SW Pennsylvania where we had pretty cold, sustained winters. There were a number of clear sunny days usually with a lot of wind. I always wanted to take advantage of that incoming radiation. We don't own our home nor did we then or I may have built a solar hot air collector. That's probably one of the simplest ways to take advantage of the insolation.

Maybe someday I'll play around with building an ASHP and rig it up on the sunny side of my home. I would think a small greenhouse bult around the Hx would at the very least keep the precipitation off and maybe reduce frosting over.

Thepprof · 04-05-13, 05:24 AM

HI; I took a Klimeaire 12K btu unit (a long story of how I got here) and charged it with R290 from my local hardware store. I used my IR scanning thermometer to scan the condensor coil to indicate the amount of charge in the system> I eventually got a Delta T of 22 degrees. I ran the system for a couple of days. This system was set up in my shop so I could play with it. Once I determined that it was working fine. I evacuated it and recharged it with R410a. re-installed it into the rental unit and it worked through the winter just fine...

Thepprof · 04-14-13, 04:03 AM

I did not realize my previous post was still on line..

Thepprof · 05-16-13, 06:46 AM

Quote:

Originally Posted by Xringer

Propane (R-290) for heat pumps? It seems to work!

YouTube - diy hvac recharge with propane

Anyhow, one of the comments on YouTube was from AlumaFX
asking about using Propane to re-fill a 14,000 btu R410A air conditioner..

I've been in contact with Aluma and he did the Mod!
It's the first DIY R410A conversion to R290 that I've been able to find..

In a PM, he told me, he used R290 all summer with great results.
8-9 amps got a 20F drop (from input to output) verses 13-14 amps
for an 18F drop using the old R410A.

He saved money on his electric bill, and it ran quieter..

It sounds like his system was designed for Propane!

Anyways, I'm really starting to think about repairing the leak in my
spare 24,000 BTU Sanyo, buying a new Sanyo indoor unit ($500), a new line-set etc,
and loading it up with deadly Propane gas!

I used R290 in a Kilmaire minisplit last year to test a unit that I thought was shot. I ended up with a 25-30 degree change at the air handler on a 95 degree day with the unit set up in my shop. Once I determined that the unit was good, since it was to go in a rental property, i purged, vacuumed and added R410 and once the unit was working in the shop properly i reinstalled it in the apartment and so far it has been doing fine..

Xringer · 05-16-13, 08:08 AM

Would you say that both refrigerants worked about the same? Or was one better?

Thepprof · 05-16-13, 01:56 PM

Quote:

Originally Posted by Xringer

Would you say that both refrigerants worked about the same? Or was one better?

I did not do a exhaustive study. did not monitor current usage. Since the minisplit does not lend the equipment to the usual line set measurements to get the proper gas in the system and I do not have scales, I used a IR thermometer and monitored the heat being released by the condensor coil to determine how much gas to add. As I added gas the area of the coil releasing heat elevated on the coil. When I started initially heat was coming from the bottom 5 inches or so as I added gas this area raised until I got close to the top. The Klimaire has a large reserve container (nearly as big as the compressor) and I felt safe at that point.

AC_Hacker · 05-16-13, 03:27 PM

Quote:

Originally Posted by Thepprof

I did not do a exhaustive study. did not monitor current usage. Since the minisplit does not lend the equipment to the usual line set measurements to get the proper gas in the system and I do not have scales, I used a IR thermometer and monitored the heat being released by the condensor coil to determine how much gas to add. As I added gas the area of the coil releasing heat elevated on the coil. When I started initially heat was coming from the bottom 5 inches or so as I added gas this area raised until I got close to the top. The Klimaire has a large reserve container (nearly as big as the compressor) and I felt safe at that point.

Too bad there were no instruments to measure before & after. But good info on your technique for finding the optimum charge.

-AC

Thepprof · 07-01-14, 05:52 AM

I have a Klimaire 12K Minisplit. The limit switch on the compressor failed and the compressor locked up. Since I purchased the unit online I knew that warranty was a joke. I took a compressor out of a 10K window unit and installed it in the unit. Set the whole system up in the shop and serviced it with propane. I had no information with regard to how much propane to charge with so simply gave it a 30 second shot and monitored the temperature change in the coils. As I added more gas the heat radiating from the compressor coils rose in the coils. When I got to a point that heat seemed to be radiating uniformly from the unit I quit. Pressures dropped dramatically, while maintaining about a 25 degree difference at the air handler. Pumped the unit down, reinstalled it and so for it is working great...

03-11-13, 05:37 AM	#192
Thepprof Lurking Renovator Join Date: Jun 2012 Location: Virginia Posts: 28 Thanks: 0 Thanked 4 Times in 3 Posts	limited experience with solar collectors Years ago I was putting a roof on a building and had several pieces of corrogated galvanized roofing left over. approximately 3 ft x 6 ft. I framed the metal with wood with a 1 in thick foam insulation back approximately 1 inch from the back of the metal and covered the front with clear plastic. The metal was painted black. I went inside to answer the telephone and a few minutes later came back to the project. the metal was so hot that it burnt my hand when I picked it up to reposition it. I leaned it against my house under a bed room window in such a way that opening the window let the heat in our out. It really kicked butt on sunny days...

04-14-13, 04:03 AM	#195
Thepprof Lurking Renovator Join Date: Jun 2012 Location: Virginia Posts: 28 Thanks: 0 Thanked 4 Times in 3 Posts	I did not realize my previous post was still on line.. Last edited by Thepprof; 04-14-13 at 04:06 AM.. Reason: Repeat

05-16-13, 08:08 AM	#197
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Would you say that both refrigerants worked about the same? Or was one better? __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

03-11-13, 10:41 AM	#193
marx290 Vapor Compression Goon Join Date: Mar 2013 Location: Portland, OR Posts: 63 Thanks: 11 Thanked 22 Times in 11 Posts	I lived in SW Pennsylvania where we had pretty cold, sustained winters. There were a number of clear sunny days usually with a lot of wind. I always wanted to take advantage of that incoming radiation. We don't own our home nor did we then or I may have built a solar hot air collector. That's probably one of the simplest ways to take advantage of the insolation. Maybe someday I'll play around with building an ASHP and rig it up on the sunny side of my home. I would think a small greenhouse bult around the Hx would at the very least keep the precipitation off and maybe reduce frosting over.

04-05-13, 05:24 AM	#194
Thepprof Lurking Renovator Join Date: Jun 2012 Location: Virginia Posts: 28 Thanks: 0 Thanked 4 Times in 3 Posts	HI; I took a Klimeaire 12K btu unit (a long story of how I got here) and charged it with R290 from my local hardware store. I used my IR scanning thermometer to scan the condensor coil to indicate the amount of charge in the system> I eventually got a Delta T of 22 degrees. I ran the system for a couple of days. This system was set up in my shop so I could play with it. Once I determined that it was working fine. I evacuated it and recharged it with R410a. re-installed it into the rental unit and it worked through the winter just fine...

07-01-14, 05:52 AM	#200
Thepprof Lurking Renovator Join Date: Jun 2012 Location: Virginia Posts: 28 Thanks: 0 Thanked 4 Times in 3 Posts	I have a Klimaire 12K Minisplit. The limit switch on the compressor failed and the compressor locked up. Since I purchased the unit online I knew that warranty was a joke. I took a compressor out of a 10K window unit and installed it in the unit. Set the whole system up in the shop and serviced it with propane. I had no information with regard to how much propane to charge with so simply gave it a 30 second shot and monitored the temperature change in the coils. As I added more gas the heat radiating from the compressor coils rose in the coils. When I got to a point that heat seemed to be radiating uniformly from the unit I quit. Pressures dropped dramatically, while maintaining about a 25 degree difference at the air handler. Pumped the unit down, reinstalled it and so for it is working great...