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Absorption Cooling

armandh

Registered
Last Subscription Date
09/02/2010
http://www.robur.com/us/

made in Ohio and used where ever there is cheap NG

and most us utilities have NG cheaper in the summer

I think they sell a lot to the mid east

I suspect that lithium bromide rather than the usual materials must work about the same way, but may need different materials to contain the reactions and likely work at different temps. [I'm not qualified to answer]
 

jht1057

Registered
It's been many years since I worked on anything with lithium bromide, the best thing I can tell you is "do not attempt to work on any part of the system if you are not qualified".
Lithium can be absorbed through the skin and has some nasty side effects.

Jim
 

Seafarer12

Registered
I know this is a little old but we have a small (30 ton) absorption chiller at the plant I work at. When they built the admin building they were trying to be "green" and put the chiller there with a solar field. We in the intrument shop call it our cool weather chiller. It works okay but it is no great shakes. Once we got all the problems fixed from installation it works but it uses a lot of natural gas to make up for the solar field even with 190 water coming in under a heavey load during summer it can't keep up. It won't make the 30 tons it is rated at. We have a 30 ton trane electric chiller that handles it no problem. The only time the chilled water starts to warm up is during a 110 degree day. The absorption chiller starts loosing ground once it hits 90. I tell people that ask about it the money would have been better spent putting in a 20kw solar array in its place. It would have been cheaper, more reliable, and probably offset the electric chiller enough so the electric usage would have been close. We have a 10kw solar array on our roof and have just about zero problems with it.


The absorption chiller we have is one of the better ones (yazaki) out of Japan. One of our other facilities had a large (3000) ton range and it is junk. It is one out of China and they have had to cut into it three times to change heat exchanger sizes and it still doesn't work. The chinese are good at Patent infringement but their engineering is lacking. If it had worked properly it would have used the waste heat off a small (3mw) gas turbine to supply chilled water.

I can see the use for them. The navy uses them alot. They are pretty compact and make use of waste heat. You just need a lot of cooling, easy on a ship. I am sure they have them worked out but I haven't dealt with any that were very goodAs far as the process it is pretty simple. There is a single circulating pump in the bottom. The entire system is in a vacuum to lower the boiling point of the water and the lithium is used as a hygroscopic in the process to help the process out. It just uses the large btu tranfer in the latent heat of vaporization. It takes a lot of btu to convert water to steam at the same temrature at lower pressures. It also takes a lot of btu's to convert steam to water. I would have to look over my training book top get the exact process down. It has been years since I looked at the stuff.
 

K D Redd

In Memory Of
The problem I am running into IS I need units in the 2, 3, and 4 Ton range. I have not contacted Yazaki, I have their web site in my Favorited list but they make nothing small.

Kent
 

Seafarer12

Registered
When we had their rep out at our plant the smallest they made was 10 ton but he was talking about they were working on a 5 ton (I think). That was a couple of years ago so they might have one worked out by now. Small ones will be hard because they cost a lot of money and usually something that small is for home use.
 

K D Redd

In Memory Of
That IS what I am looking for, something for home use. I want to use solar heat to power it. Ultimately I would like to see a system that would use a Sterling engine to do the pumping of the weak and strong lithium solutions.

Kent
 

Seafarer12

Registered
You would need a LOT of solar to heat it. We are in Texas and ours can barely keep up if it is much less that 100. You need 180 degrees to get optimum performance out of the chiller. If you can't maintain it you need a boiler to make up the difference. So for cooling at night you would run purly on natural gas. If you drop much below 180 on your chilled water goes to crap.

Like I said earlier it would be better to just buy solar panels and use the power produced to offset an electric unit.
 

JeffK

Subscriber
Last Subscription Date
02/09/2020
We had a 40 ton and an 80 ton Yazaki they were ok when new but as time went on they were always acting up. Even the experts from Yazaki could only make them work for a few days at a time. We went back to a York chiller and a tower.
 

SparkChaserJoe

Registered
Hello! I am new to the page. I am close to Houston TX. I have several ideas that have came together over the years. I would appreciate any thoughts on them. This all started with the high cost of cooling and an article I read about a man in California that had dual electricity rates, day and night. He froze water at night and used the cool water to cool the house. Recently I have been curious about absorption cooling. I also like the Lister Diesel to make power because hey are really efficient and dependable. I was wandering if I could use the waste exhaust heat from a generator to drive a small, maybe 10 ton Absorption system to freeze water. I would like to run a few hours a day to provide the cooling needed. From what I have read it takes about 20,000 BTUH to drive the absorption systems. Seafarer12 mentioned a solar array to heat water, or is it preheat water. I am wondering what the temperature is of the water is coming out of the absorption system headed to the solar array. There also has to be a cooling system, like a cooling tower. How much heat does it have to handle, reject? I assume the heat from the cooling and the heat used to power the chiller. So, for the 10 ton unit, would that be 200,000 BTUH used to drive it and the 120,000 BTUH of cooling?
Seafarer12, you mentioned a Solar Array as the best way to offset the power requirements in the system y'all have where you are. I have resisted Solar because I thought it was only effective for about 4 hours a day if you have good sunlight. I am fairly close to the Gulf of Mexico and we have a fair amount of cloudy days. I guess I could start with a panel and see how it performs. I am rural so power outages is a concern too. I have a generator for outages now but fuel is expensive. I set the generator up in the attached garage and fabricated an exhaust to run outside. I installed an exhaust fan to pull heat and fumes outside. I still do not care to run a generator while everyone is asleep. So I have two small banks of batteries tied to two APC UPS. One runs my TV systems DSL and all and the other will run my Lighting. I have converted over to LED's except for two Florescent lights for that to work. I do not want to be off grid but would like to be able to supplement my high power usage and be able to run for a few weeks when the power fails. The UPS help too because we will loose power for a second or so and that reboots everything and they prevent surges. I have thought about wind turbine but I am in Pine wooded area. Before thinking about this I was thinking about a Ground Source Heat Pump. Likely though the money would be better used to upgrade insulation and all instead of the absorption system. I also wandered about running a belt driven AC system. A lot of times I think wrong, I get to beating my head against the tree and can't see the forest so any thoughts would be greatly appreciated. Thank y'all! Joe
 

phabib

Registered
I saw the system that makes ice at night and cools during the day at a trade show maybe 15 years ago. I don't know if its still made. I read at the time that the inventor was never able to work out a royalty agreement to have it built and it was only after he died that his heirs got an agreement in place. It had a tub maybe 4x4x3 feet filled with water that it froze at night using off peak electricity rates then used that for cooling during the day. Looked like a smart way to go if you could live with the extra up front cost.
 

Warpspeed

Registered
That IS what I am looking for, something for home use. I want to use solar heat to power it. Ultimately I would like to see a system that would use a Sterling engine to do the pumping of the weak and strong lithium solutions.

Kent
I was not personally involved with the particular project, but many years ago I know of a solar based airconditioning system bases on a large Yazaki absorption chiller, and a whole series of concentrated tracking vacuum tube solar collectors. It was a rather large and expensive system by most standards.
It was installed in a service station / road house on a busy freeway linking interstate in Australia. It was all well before the internet, so there is probably nothing to search for.

The problem with any absorption chiller is you need a very good constant reliable source of heat energy to drive it. Even a slight fall of of the heat source temperature is devastating to overall chiller efficiency. You will clearly see that from the performance curves.
That was its major downfall for a solar application.

A practical solar based absorbtion system, to have good consistent performance really needs an auxiliary heat source such as natural gas to kick in, when solar is marginal, such as with scattered cloud on a really hot day.
For the money spent, it was not a terrific result, and generally given the thumbs down by the owner.
Fortunately this particular project was largely funded from a government grant, but when the money stopped flowing the owner quickly ripped the whole lot out.

Your location and what you expect from the system may (?) make it viable, but you will need to do a lot of very careful research and a full engineering assessment to decide if it will be workable, or just become a big liability.
If you have a HUGE free constant thermal heat source, (such as geothermal) at sufficient temperature, I would say go for it.

Alternatively a more conventional solar/electric system, with a large battery, and conventional motor driven heat pumps/air conditioners may very likely be less risky from an engineering and a financial point of view.
There is far more knowledge and experience with something like that, and far easier to predict the performance.
 

Drangd1

Registered
Hello! I am new to the page. I am close to Houston TX. I have several ideas that have came together over the years. I would appreciate any thoughts on them. This all started with the high cost of cooling and an article I read about a man in California that had dual electricity rates, day and night. He froze water at night and used the cool water to cool the house. Recently I have been curious about absorption cooling. I also like the Lister Diesel to make power because hey are really efficient and dependable. I was wandering if I could use the waste exhaust heat from a generator to drive a small, maybe 10 ton Absorption system to freeze water. I would like to run a few hours a day to provide the cooling needed. From what I have read it takes about 20,000 BTUH to drive the absorption systems. Seafarer12 mentioned a solar array to heat water, or is it preheat water. I am wondering what the temperature is of the water is coming out of the absorption system headed to the solar array. There also has to be a cooling system, like a cooling tower. How much heat does it have to handle, reject? I assume the heat from the cooling and the heat used to power the chiller. So, for the 10 ton unit, would that be 200,000 BTUH used to drive it and the 120,000 BTUH of cooling?
Seafarer12, you mentioned a Solar Array as the best way to offset the power requirements in the system y'all have where you are. I have resisted Solar because I thought it was only effective for about 4 hours a day if you have good sunlight. I am fairly close to the Gulf of Mexico and we have a fair amount of cloudy days. I guess I could start with a panel and see how it performs. I am rural so power outages is a concern too. I have a generator for outages now but fuel is expensive. I set the generator up in the attached garage and fabricated an exhaust to run outside. I installed an exhaust fan to pull heat and fumes outside. I still do not care to run a generator while everyone is asleep. So I have two small banks of batteries tied to two APC UPS. One runs my TV systems DSL and all and the other will run my Lighting. I have converted over to LED's except for two Florescent lights for that to work. I do not want to be off grid but would like to be able to supplement my high power usage and be able to run for a few weeks when the power fails. The UPS help too because we will loose power for a second or so and that reboots everything and they prevent surges. I have thought about wind turbine but I am in Pine wooded area. Before thinking about this I was thinking about a Ground Source Heat Pump. Likely though the money would be better used to upgrade insulation and all instead of the absorption system. I also wandered about running a belt driven AC system. A lot of times I think wrong, I get to beating my head against the tree and can't see the forest so any thoughts would be greatly appreciated. Thank y'all! Joe
https://www.roburcorp.com/chillers/gas_absorption_chiller_ga_acf
There is a company called Robur that seem to work.
I looked into them seriously when I needed a new 5 ton ac in Phoenix.
The first thing is the cooling falls off the hotter it gets. These are gas fired.. Regular AC's do as well but not as bad. I got upside down with the local folk when I wanted to put a automatic water filler on the unit. The said that would void the warranty. Understand this was all looked into in the late 90's. The tech might be better now.
The first house I had in Phoenix had an absorber. Worked great, except that the service guy had to work on the system to change it over to heat, and back again for cooling. I think they have a place, IF you have a lot of waste heat and the need for a lot of cooling 24/7/365.

The freeze thaw cycle is used a lot for large commercial loads.
Northwind used to run the ice bank for Bank One Ballpark. They had 2- 2000 ton chillers to freeze the ice bank overnight and run the chilled water pipes through it during the day. Really do not think ice is the answer for very many residences. My new home I am using GREE inverter heat pumps. Looking forward to a solar array in the future I thought it best to get a unit that was happy with a larger voltage difference. Arizona State University used to have the largest chilled water plant west of the Mississippi. I believe there were 6-2000 ton machines and 3-1.1 million gallon subterranean storage tanks. When everything was running after 9 pm when the electric rate fell, the U was the 5th largest load for the power company in the state. (again in the 90's) There are some mines in AZ that have huge electric footprints.


Have you thought about a single axis solar tracker? Check Utube and you will see you can get 10-30% more power. Numbers are from the internet not me. I do not have an array yet.

thoughts from the cheap seats
 

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