small ammonia chiller design?

[kwfiggatt]

Hey folks,

I've been lurking for a while and have interest in NH3 systems. I'm trying to build a small ammonia chiller to act as my house air conditioner and am looking for pointers. Before you call me crazy, this system is going to be housed in my pool shed, away from my house. I plan on piping chilled glycol to an indoor fan coil.

I have a 3x3 belt drive Howe compressor out of an old slaughter house that I was given, so that's probably going to be the compressor. I was planning on driving with a 6HP Listeroid diesel engine. I'm trying to come up with the rest of the details of the refrigeration plant. My cooling load is around 3 tons (size of my current AC, which seems to be sized about right) which is a little small for the 3x3, from what I can gather, so I'm planning on cycling the compressor with a clutch and maybe using ice storage. I have lots of pool water that I can use for condenser cooling.

I was thinking of running tube&shell evap and condenser, running as a flooded thermosyphon setup.

Ideas, thoughts, am I nuts?

Kevin

[NH3ISFORME]

Don't know if your in the US or not. I guess if you're under 10,000 lbs you won't need a PSM. So you got that going for you.

[josei]

I think is a very expensive layout to get only 36000 btuh AC.Good luck!

[Balanced Energy]

Start Slowly.. You can convert your current AC system into a water cooled condenser.
You can use the same method to convert the cold side to water exchange too. If you have a year round pool and a heat pump you can heat and cool. Make sere to use glycol on the inside loop.

Home Depo Passthrough Exchanger for three tons listed EACH 18 feet of 3/4 PEX 20 feet of 3/8 roll copper 1 stick of 3/4 copper 2 3/4 copper ts
2 copper 3/4 female npt to sweat 2 3/4 mpt to 3/8 compression 4 3/4 sharks tooth

Assemble the ts with two 6 inch stubs of copper at 90 degree angles, install 3/4 female on last side of ts and install compression fitting. Pass the 3/8 copper through the PEX, install one sharks tooth on each end of the pex, pass the assembled Ts over the 3/8 copper stubs making sure you have at least one foot of copper past the compression fitting. Push sharks tooth together and tighten compression fitting.

At the condensing unit Cut discharge line at compressor and liquid line to house and weld in heat exchanger. The two remaining copper stubs are for water in and out. On the water inlet side (liquid line to house) it is MANDITORY that you use A head pressure controlled water metering valve, if not you will have too much subcooling and the inside coil will freeze. The water outlet must be on the compressor discharge side to avoid BOIL SHOCK......

My system is tied to a 400 gallon 12 person hot tub. I cut the 1.5 inch line after the filter and installed a reducer T to send water to the ac heat exchanger, the hot water supply is mounted to a riser with a two way zone valve, when the tub reaches 104 degrees the air pump comes on and the hot water is diverted to a rain assembly.

Year round pools can use heat pump technology just make sure and use glycol inside and a pool water freeze protector out. You would also have to convert your AHU to a hydronic variety.

[kwfiggatt]

Start Slowly.. You can convert your current AC system into a water cooled condenser.
You can use the same method to convert the cold side to water exchange too. If you have a year round pool and a heat pump you can heat and cool. Make sere to use glycol on the inside loop.

Home Depo Passthrough Exchanger for three tons listed EACH 18 feet of 3/4 PEX 20 feet of 3/8 roll copper 1 stick of 3/4 copper 2 3/4 copper ts
2 copper 3/4 female npt to sweat 2 3/4 mpt to 3/8 compression 4 3/4 sharks tooth

Assemble the ts with two 6 inch stubs of copper at 90 degree angles, install 3/4 female on last side of ts and install compression fitting. Pass the 3/8 copper through the PEX, install one sharks tooth on each end of the pex, pass the assembled Ts over the 3/8 copper stubs making sure you have at least one foot of copper past the compression fitting. Push sharks tooth together and tighten compression fitting.

At the condensing unit Cut discharge line at compressor and liquid line to house and weld in heat exchanger. The two remaining copper stubs are for water in and out. On the water inlet side (liquid line to house) it is MANDITORY that you use A head pressure controlled water metering valve, if not you will have too much subcooling and the inside coil will freeze. The water outlet must be on the compressor discharge side to avoid BOIL SHOCK......

My system is tied to a 400 gallon 12 person hot tub. I cut the 1.5 inch line after the filter and installed a reducer T to send water to the ac heat exchanger, the hot water supply is mounted to a riser with a two way zone valve, when the tub reaches 104 degrees the air pump comes on and the hot water is diverted to a rain assembly.

Year round pools can use heat pump technology just make sure and use glycol inside and a pool water freeze protector out. You would also have to convert your AHU to a hydronic variety.

Awesome info! Thanks for the heat exchanger idea - that sounds like it's up my alley. If I'm going to use NH3, I'll have to use aluminum line and steel piping and maybe some stainless swagelock fittings.

I have a ~14,000 gallon pool that I plan on tying in to. I could use the same system that you've done, except have the set point on the zoning valve set to a decent pool water temp then divert to the sprayer head. Do you have to add a lot of makeup water to the hot tub during the summer due to evaporation?

I do keep water in the pool all year and do have a heat pump, so I will try to set it up that way.

What's boil shock? I understand running the hot water out of the HX at the compressor discharge end to get best performance out of the HX, but am unsure about boil shock.

Anyhoo - thanks for the good info.

Kevin

[simplygold]

Good luck! I'm very interested to see how this will pan out. Some materials that may be of use to you throughout your project may include:

1. Stainless Steel or Thick walled mild steel tubing. Very easy to work with if you have the proper tools. 3/8 and 1/2 are good sizes for oil lines on the compressor and even great for homemade HE.

2. They sell absorbtion central air systems for homes now. Talk with you local HVAC company to find more info.

3. If the system is to large for the application, consider adding a cold storage for perishable food. Like a 10x10 room... This will increase the heat load some, depending on how well your room is insulated and how often the door is open.

[McFranklin]

So let me get this straight, you have a junk compressor, a junk diesel motor and you want to cobble it together so that in the MIDDLE OF SUMMER you add HEAT to your swimming pool. Your location says West Virginia. Are they giving away diesel? And are you going to run a belt drive for the water and glycol pumps?
As to your sanity, well we couldn't put you in a nuthouse, but if we had you, we would have to let you out.

[kwfiggatt]

So let me get this straight, you have a junk compressor, a junk diesel motor and you want to cobble it together so that in the MIDDLE OF SUMMER you add HEAT to your swimming pool. Your location says West Virginia. Are they giving away diesel? And are you going to run a belt drive for the water and glycol pumps?
As to your sanity, well we couldn't put you in a nuthouse, but if we had you, we would have to let you out.

Yeah, you have most of it right - the engine's actually a relatively new Listeroid 6HP, 650 RPM single cylinder engine from India that I currently use as my backup generator but the compressor's definitely used.

The main goal is to be able to cool the house. I'm currently working on a setup so I can drill geothermal wells, which is ultimately where the heat from the condensor will go. Dumping it into the pool is until I get the ground loop installed. I'll probably rig it up so I can turn it into a heat pump for winter heating, too. Maybe I need to stick to one project at a time... Get the ground loop installed first?

As for giving away diesel - I'm running the engine on waste engine oil. I work at a place that generates LOTS of it and will give it to me...

For the water and glycol pumps - I was planning on running them on electricity. The engine (burning waste oil) is currently hooked up to a generator that can power the pumps, too. So ultimately I'll have free AC & heat, powered by waste oil.

Maybe this explains my sanity level a little bit more...

Kevin