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.
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.
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.
I had a neighbor in the 70s that had NG central air in his house. Haven't seen a residential system like since then.
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
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.
Scroll down and youll find the Manufacturer of these now :
The Gas company used to sell N.Gas Central air. very expensive today to purchase.
>I wonder about using a NG generator, to produce the electric to run the system?
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"W" wrote in message news: snipped-for-privacy@giganews.com... 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.
Does anyone here have experience with the Robur Ammonia natural gas chillers?
The problem with that approach is you will have an engine running 24x7. Most generators are designed for short term usage. Once you cycle up to long duty cycles you are looking at turbine systems, and those are hellishly expensive for residential use.
For cooling, you'd need a drip pan and drain, of course.
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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.
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.
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.
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.
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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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.
Is there no such thing as a natural-gas-powered A/C compressor?
It could double as a low-power electrical generator during blackouts?
Honda made something like this for the residential market in northern Japan a few years ago. I think perhaps that was just a furnace with small electrical generator.
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.
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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