Natural Gas HVAC

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With natural gas pricing getting so low and looking to stay below $3 per Mcf for a long time, has anyone managed to come up with a good HVAC system run by natural gas? I am aware of hybrid systems used for the furnace, where a controller switches between a heat pump and natural gas furnace, depending on outside temperature and whether gas or electrical is cheaper. I am asking about using natural gas as the fuel for the cooling system.
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W



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For large commercial and industrial applications, natural gas fired cooling systems have been available for decades.
For home use, afaict there ain't no such beast these days.
York had their "Triathlon" system for homes in the late 1990s. No longer around.
https://en.wikipedia.org/wiki/Triathlon_%28heat_pump%29
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Arkla Servel made absorption chillers back in the 60's and 70's. Used to service a lot of them. Sadly, we see fewer out there every season. They must be expensive to manufacture given then ammonia in them requires heavy steel containers, stainless coils, etc. Then you need the chilled water lines & coil. It's a great idea but, with the initial cost and not enough trained service personnel in place the price would be too high.
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I had a neighbor in the 70s that had NG central air in his house. Haven't seen a residential system like since then.
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On 4/13/2012 11:18 PM, W wrote:

Alabama Gas once sold and serviced them here in Alabamastan. The last one I saw was back in the 1990's. The units were the ammonia/hydrogen sealed systems like the camper refrigerators that run off LP gas. o_O
TDD
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Youre referring to an Absorption A/C Unit . Way back, Arkla Servel and Bryant offered these and the local gas utilities used to promote them . I worked on one in my career and they are THE most unsightly looking things ever devised. A 3 ton capacity Bryant used to stand about 4 foot high by 5 foot wide and 3 foot deep. The way it worked, was, the Absorption Unit would chill circultating water thru it down to about 44 f. then a small pump would pump the water into a water coil within an Air Handler or above a Gas fired Furnace into a seperate water coil . You can do a google as im sure youll find a couple manufacturers who still produce these wet dreams of theirs.
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Scroll down and youll find the Manufacturer of these now : http://www.gasairconditioning.org/residential.htm
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Does anyone here have experience with the Robur Ammonia natural gas chillers?
http://www.roburcorp.com/products/gahp-line/air-to-water-reversible-heat-pump-ar-rtar-series/description.html
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W


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Assuming this thing actually works, it would circulate both hot and cold water in a hydronic system. Does anyone make a wall mounted hydronic radiator that would do cooling as well as heating?
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W




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For cooling, you'd need a drip pan and drain, of course.
Christopher A. Young Learn more about Jesus www.lds.org .
http://www.roburcorp.com/products/gahp-line/air-to-water-reversible-heat-pump-ar-rtar-series/description.html
Assuming this thing actually works, it would circulate both hot and cold water in a hydronic system. Does anyone make a wall mounted hydronic radiator that would do cooling as well as heating?
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W







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Well, Multiaqua claims to have hydronic fan-coils that resemble the DX indoor unit to a mini-split unit. They also claim to have small air cooled chillers.
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"W" wrote in message

I live in Australia and as far as I know, you need by law here, to have 3 stages of cooling away from the ammonia in air conditioning
1/ The ammonia refrigerant. 2/ Brine 3/ Chilled water. 4/Air
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Sorry bit there is no way I would ever install an ammonia air conditioning system.
Ammonia is poisonous, it is inflammable and explosive.
http://www.chemplex.co.zw/index.php?option=com_content&view=article&id 4&Itemid"4
//Anhydrous ammonia is poisonous and can cause severe burns. It should be stored away from heat or direct sunlight, to prevent excessive pressure build-up. Ammonia gas is inflammable and can cause explosive mixtures with air.\\
If you have worked with it is very nasty stuff.
If it gets loose and it gets into your eyes and lungs it turns in to a highly caustic mixture with the moisture there causing burning. It can kill, and it does.
Yes Ammonia is a great effective refrigerant , but not as a refrigerant for domestic purposes, especially not for air conditioning. in any shape or form.
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Any chiller is going to work by circulating cold / hot water to either a forced air coil or to a radiator / radiant heating coil. What application did you have in mind that would expose air in the home to the ammonia? It's not clear what use case you are avoiding.
Natural gas is also hazardous if it escapes, yet it's an extremely common and safe way to provide heating. I would worry about a natural gas line breaking with much higher probability than ammonia leaking from a chiller? It would be interesting to hear how often that happens with chillers based on ammonia.
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W



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"W" wrote in message

Sorry chilled water is not something that would work with a radiator.
Have you had any experience with ammonia as refrigerant?
If you have you would know just how bad it is if it leaks.
Get an ammonia leak and they evacuate buildings, or suburbs if it is bad enough.
Direct expansion ammonia (Steel) cooling coils if leak would poison the atmosphere.
If Ammonia was used to cool chilled water and it leaks into the chilled water it would create problems as ammonia attacks copper, the air cooling coils and the copper pipework, then it would get loose in the air of the building.

You would not want to be around if ammonia gets loose. Ask any refrigeration mechanic how many times they have repaired refrigerant leaks in air conditioning systems.
First of all ammonia is fairly high pressure and natural gas coming into a home from the street is fairly low pressure, quite a difference if you get a bad leak.
Natural gas pressure varies on location but it is quite often 10 psi (From the gas main not a bottle) and much less after the gas governor reduces it further.
Ammonia depending on the system will also vary but in a non operation system at say 70 f degrees ambient it would be around 100 PSI, at 100 f it would be around 200 PSI.
A huge difference to natural gas if you get a leak.
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These ammonia systems are an absorption refrigeration system IE heat used to produce cooling.
The ammonia is the refrigerant and water is the absorber.
A later system which is safer uses water as the refrigerant and lithium bromide as the absorber.
If you are seriously thinking about an absorption system then I would check the actual amount of heat needed to be put in to produce the cooling.
A few years ago I did a check and found they were quite inefficient compared to a standard compressor system. You need a huge amount of heat to produce the cooling.
They come into there own where you have a lot of waste heat, IE a factory that uses steam and there is heaps of waste heat to use in the absorption system.
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I did not see it but was told of a building that generated its own power though motor generators and used the heat from the motors (Exhaust and cooling heat) to run an absorption cooling system (water /Lithium bromide) they also used the heat from the motors for domestic hot water and heating.
From a domestic view point I could not see where that would be practical though.
For instance
I have a 27 KW diesel generator as a standby unit (I live is a cyclone area) and in 24 hours it consumed 75 litres of diesel (US about 19 gallons) Diesel here cost around $1.56 per litre
I would not want to be running that for long.
By comparison my 6.5 HP air conditioning system draws an bout 12 amps per phase (415 volts), say 9 Kw while the compressor is running on cooling. We pay around 16 cents per Kw,about $1.44 per hour.
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On 4/25/2012 2:33 AM, snipped-for-privacy@truthonly.com.Sword of Baal wrote:

The N gas air conditioners used Ammonia to chill water at the outside unit and then pumped that chilled water through an A coil at the air handler. They seldom if ever had a leak. Ammonia is a very useful tool for the air conditioning, cooling and freezing needs. Due caution must be taken in handling it just as in handling any coolant gas. There a many more fatalities from the use of common gasoline then from Ammonia or Sulfur Dioxide..etc. Training in proper usage and care is essential. I guess that is why we get the big bucks.

Balderdash.. The N.gas air conditioners were super cheap to operate and seldom needed maintenance. They ran until overhaul was required after many years. Their actual demise was created by high initial cost and lack of trained personal. Nobody wanted to specialize in them as they seldom broke down. No money in sitting on your ass waiting for grass to grow and repair calls. The Gas companies subsidized their initial installation. We in the HVAC industry destroyed that market by a lawsuit against the US Government for allowing the taxpayer subsidized N gas utility companies to unfairly compete with us in private industry. That successful lawsuit brought by Eastern HVAC Unions stopped the N. Gas companies from selling or servicing HVAC equipment. No private enterprise wanted to subsidize *ANY* A/C unit...much less a gas one that required very little repair and maintenance.

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"PaxPerPoten" wrote in message of Baal wrote:

Sulphur Dioxide
Goodness me that went out of use, what, 60 years ago?
No wonder no one has died from it recently, it was a very nasty stuff when it hit moisture (your eyes and lungs),it turned into sulphuric acid
Also one of the problems with sulphur dioxide was that in domestic fridges (open units) it had to run under vacuum to produce the right amount of cooling, and running under vacuum is not a good idea. As far as I know it was never used in sealed units.
As for ammonia killing people.
http://norfolk.injuryboard.com/workplace-injuries/will-dangerous-ammonia-refrigeration-systems-be-phased-out.aspx?googleid &5312
//Every year ammonia refrigeration systems cause accidents and explosions in large commercial factories across the United States. Although large companies are aware of the risks of using ammonia refrigeration, it is very important that companies inform their workers of these risks as well. Workers who may be exposed to ammonia or become victims of an ammonia blast should know the potentially lethal effects of this chemical. Even a small leak in these refrigeration systems can have deadly consequences if not caught in time. Ammonia refrigeration is very dangerous because when the chemical is mixed with air in the 16%-25% range it can cause a large explosion capable of leveling an entire building. The ammonia itself is also very toxic and is corrosive to the eyes, skin, and lungs. Workers involved in ammonia accidents of this type are likely to sustain severe injuries and burns if they survive. Even though ammonia is a serious health hazard, many large corporations choose to use this type of refrigeration because of ammonia&rsquo;s heat transferring properties, its cost effectiveness, its wide availability, and its low impact on the environment\\

Like to show that by how much gas they use to produce cooling?
I notice that the producers of absorption systems air conditioning fail to quote the actual amount of heat they need to produce their cooling, when I checked it out it was around twice the amount of heat to get the cooling. Yes this may have improved since then
So I will wait for you to produce facts and figures backed up with URLs showing the tonnage of the system and the amount of heat required to produce this, tonnage.
After all you did say they were super cheap to run......................
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On 4/28/2012 4:42 AM, snipped-for-privacy@truthonly.com.Sword of Baal wrote:

I take it your coolant Certification is either nonexistant or is not a Universal.
what, 60 years ago?
It is still around and still in use for certain needs. Do you really think that such technology dies just because you don't understand it or are afraid of it? Maybe we should use nuclear units for our absorption units and really make you piss your britches.

Are you just learning that?

So do cars when improperly utilized or are in an accident. I suggest you check out packing plants and Blast cooling plants. We have had 2 fellows from Minnesota killed while charging and recovering R410A in the last few years. Many have suffered death or injuries while charging R12 in in Automobile systems. Hell, Out in California a Sail Boater even died by choking on too much bubble gum. Ever hear of reefer ships for transporting spoilable goods. Navy and Coast Guard have lots of them.

http://norfolk.injuryboard.com/workplace-injuries/will-dangerous-ammonia-refrigeration-systems-be-phased-out.aspx?googleid &5312
Apparently your method of checking is flawed.
and found they were quite inefficient

Why don't you go to the N Gas suppliers for that information? I will again state that the N Gas A/C were very efficient and cheap to operate. Much cheaper then electric. I would also suggest the Physics department at MIT for information.

I guess that is why recreation Vehicles use absorption refrigerators. Even though the units are a bit high priced..they are favored. No change in decades.

I take it you are another loudmouth that requires others to do *Your* Homework. Might I suggest a good Thermodynamics course at a rated Institution of higher learning?

Yes I did. And you have yet to disprove that. Or that the Gas suppliers data was incorrect. I did also state that the initial cost of the equipment was expensive.

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"PaxPerPoten" wrote in message
It seems we have here PaxPerPoten a labourer who cleans filters and thinks he is a refrigeration engineer.

Yes in wine etc..
Show where it is still used as a refrigerant.
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Household natural gas absorption air conditioning units.

Is it now.

I do not need to as I have proof of just how much heat they need to produce cooling, something you dodged. You are typical of big mouths who raves and do not know what they are talking about.
Here is a current unit.
AR Series GAHP Line
http://www.robur.it/documenti_prodotto/ROBUR_Pocket-Product-Guide_092009-20090917141620.pdf
Cooling capacity BTU/h 57,700 Gas input BTU/h 95,500
That is 95,500 BTUs of gas to produce under 5 ton of cooling. Of course then you have to add the cost of electric power require to make them operate
Operating consumption kW 0.75
As I said previously "I checked it out it was around twice the amount of heat to get the cooling. Yes this may have improved since then"
By looking at these numbers it does not seem to have got much better, despite your ravings.
BTW your statement of "The N.gas air conditioners WERE super cheap to operate." indicates in earlier times, BEFORE the cost of natural gas got so low.
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The reason they use absorption refrigerators is simply power availability. Rec vehicles can be where there is no mains power and to run a fridge off the batteries would mean running them flat within 12- 24 hours if there was no way of charging them available. If you were at a no power camping site for a week of so you would have no refrigeration, with a gas absorption refrigerator that is not a problem.
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"ramrod"@truthonly.com.Sword of Baal wrote:

I ask again.
Are there any residential-sized AC compressors that have nat-gas powered motors?
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This time, pay attention......
http://en.wikipedia.org/wiki/Triathlon_(heat_pump)
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