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.

--
W



Re: Natural Gas HVAC

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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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_____________________________________________________
Knowledge may be power, but communications is the key
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Re: Natural Gas HVAC
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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.

Re: Natural Gas HVAC

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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.

Re: Natural Gas HVAC
On 4/13/2012 11:18 PM, W wrote:
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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

Re: Natural Gas HVAC
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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.

Re: Natural Gas HVAC
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Scroll down and youll find the Manufacturer of these now :
http://www.gasairconditioning.org/residential.htm

Re: Natural Gas HVAC
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

--
W


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Re: Natural Gas HVAC
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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?

--
W




Re: Natural Gas HVAC
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?

--
W







Re: Natural Gas HVAC
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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.



Re: Natural Gas HVAC



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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

-------------------

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=164&Itemid=224

//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.


















Re: Natural Gas HVAC
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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.

--
W



Re: Natural Gas HVAC



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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.


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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.

---------------------

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.

------------

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.

==================================================





Re: Natural Gas HVAC
On 4/25/2012 2:33 AM, ramrod@truthonly.com.Sword of Baal wrote:
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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.
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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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Re: Natural Gas HVAC



On 4/25/2012 2:33 AM, ramrod@truthonly.com.Sword of Baal wrote:
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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=265312

//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’s heat transferring properties, its cost effectiveness, its
wide availability, and its low impact on the environment\


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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......................








Re: Natural Gas HVAC
On 4/28/2012 4:42 AM, ramrod@truthonly.com.Sword of Baal wrote:
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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.
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Are you just learning that?

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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.

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http://norfolk.injuryboard.com/workplace-injuries/will-dangerous-ammonia-refrigeration-systems-be-phased-out.aspx?googleid=265312
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Apparently your method of checking is flawed.

  and found they were quite inefficient
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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.
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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.
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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?
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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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Re: Natural Gas HVAC




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


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Yes in wine etc..

Show where it is still used as a refrigerant.

-------------------------

Household natural gas absorption air conditioning units.


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Is it now.

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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.



Re: Natural Gas HVAC
"ramrod"@truthonly.com.Sword of Baal wrote:
 
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I ask again.

Are there any residential-sized AC compressors that have nat-gas powered
motors?

Re: Natural Gas HVAC

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This time, pay attention......

http://en.wikipedia.org/wiki/Triathlon_(heat_pump)



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