Friday, December 14, 2012

HVAC Absorption Chillers vs Electric Chillers

In any HVAC system,selection of chillers involve many factors to be considered judiciously.These factors simultaneously present many advantages and disadvantages to end users.For the selection of water chillers,HVAC engineers consider all these factors keeping in view all the resources they have at their facility.
HVAC chillers
Absorption chiller vs electric chiller

Comparison of Absorption Chillers and Electric (Compression) Chillers

Following is the comparison of absorption chiller and electric chiller is presented below with aim to help you to decide the type of chillers for HVAC  system.
    absorption vs compression
  1. Absorption chillers have COP (coefficient of performance )of only 0.54–1.1 and it competes poorly with electric chillers (rotary compressor chillers). Electric chillers on other hand have COP from 1.0 ~ 8.0. 
  2. Absorption HVAC chillers occupy approximately 50% more floor area than the equivalent  electric chillers (vapor compression chillers). 
  3. Additionally due to height of absorption chillers, mechanical equipment rooms must be 6–10 ft taller than rooms housing electric chillers. Finally, because the liquid solution is  contained in long, shallow trays within an absorption chiller, the floor must be as close to absolutely level as possible.
  4. In HVAC system,Absorption chiller will weight at least twice as much the equivalent electric chiller  (vapor compression chiller). 
  5. Due to greater  size, absorption chillers are sometimes shipped in several sections, requiring field welding for final assembly.This is not case with counterpart electric chillers or compression chillers. 
  6. Most of electric water chillers are shipped from the factory with their refrigerant charge  installed.While the refrigerant and absorbent (including additives) must be field installed in absorption HVAC chillers. 
  7. When we talk about noise and vibration, absorption chillers (unless direct-fired) are quiet and essentially vibration-free as compared to compression chillers (electric drive chillers). Noise and vibrations in HVAC system annoy more than anything else . 
  8. Due to the potential for crystallization of the lithium bromide in the chiller if it becomes too cool, the condenser water temperature must be kept above 75–808F.There is no problem of crystallization in electric chillers (vapor compression chillers). Forget about the crystallization and stay cooled if you have installed compression chillers . 
  9. Absorption water chillers require sometimes an emergency power source if lengthy power outages are more often expected. Without power and heat input, the chiller begins to cool and the lithium bromide solution may crystallize. However, as absorption chillers consume very little electric energy so a small dedicated back-up generator can serve this purpose well. 
  10. HVAC system also gives importance to the amount of heat to be rejected in condenser by water cooling or air-cooling media.The heat rejection rate from the condenser of lithium bromide chiller is 20–50% greater than for the equivalent electric chiller, requiring higher condenser water flow rates and larger cooling towers and condenser water pumps. 
  11. Finally, an indirect-fired absorption water chiller will be at least 50% more expensive to purchase than the equivalent electric-drive chiller. Direct-fired absorption chillers will cost almost twice as much as an electric machine, and have the added costs associated with providing combustion air and venting (stack). 
  12. Absorption water chiller or lithium bromide chiller uses natural refrigerants such water and eliminate the need of CFC or HCFC refrigerants which have high global warming potential. 
  13. If you have plenty of waste heat or direct fire available ,and want to reduce your electric load ,then probably absorption chillers are the best solution.But obviously all above factors are to be considered for the selection of HVAC water chillers.

Comments (80)

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Which type of heating and cooling product is this?
1 reply · active 275 weeks ago
Thanks for sharing! I just checked out a bunch of hvac systems and got a new one installed recently. I have yet to check out these chillers. Great information, thanks again!
thanks for visiting my blog and do appreciated your nice comments.
John Wood's avatar

John Wood · 630 weeks ago

Nice blog for me and info is quite valuable. I suggest every one, looking for best commercial refrigeration repair in NJ so Bergen Refrigeration is so cool to provide reliable HVAC services.
nice blog it is very informative for me because i am also a Hvac service provider. so it is very useful for me,,,,,,,,,,,
Chillers are explained well enough. thanks for your information.
allanmurray's avatar

allanmurray · 608 weeks ago

Very well said, this is one of the most comprehensive HVAC info.
ac Install heath
Very interesting post! I agree with you, when it comes to HVAC systems, you need to take many factors into consideration to select chillers.
thanks for posting!
Nice post ! It is very useful and i agree with you about all the fact of HVAC systems.If anyone looking for Water Cooled Chillers then dpac UK provides best products and reliable services.
good sharing..thanks
Nice Comparison of Absorption Chillers and Electric (Compression) Chillers. Excellent post!
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Steven Cohen, PE's avatar

Steven Cohen, PE · 573 weeks ago

This explanation is not completely accurate. Absorption chillers do have a lower cycle efficiency than electric equipment but sometimes their fuel source is much cheaper than electric equipment making them much more economical. Gas fired absortpion chillers use gas in the summer which is an off peak fuel against on peak summer electric is very economical especially combined with a demand side management system. In addition, absorption chillers can be used for waste heat recovery in cogeneration systems and for solar thermal cooling. They have their place so don't be so fast to write them off.
Steven Cohen, PE's avatar

Steven Cohen, PE · 573 weeks ago

Crystallization in absorption chillers is a non-issue thanks to modern controls that can respond quickly to changes in the internal heat balance of the machine.
Hi, Nice blog I had a great time reading it. Can I contact your through your email? Please email me back. Thanks!

Randy
randydavis387 at gmail.com
Perfect post, highly informative and professionally written..Good Job
Steven Cohen, PE's avatar

Steven Cohen, PE · 572 weeks ago

Contact the person below in NYC for significant rebates of up to $600/ton to use absorption chillers so don't write them off too fast:
David R. Pospisil, CEM
Manager, Commercial & Industrial Energy Efficiency Programs
Con Edison Company of New York
4 Irving Place, Floor 10NW
New York, NY 10003
Office (212) 460-2429
Email pospisild@coned.com
Twitter @dpospisil
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I like how you added a lot of pros and cons for both types of system. I honestly don't even know what type of system I have installed in my home. I can probably go home and figure it out after reading this article. I can't even remember the last time I went in the room where my system is located. <a href="http://www.pro-staffmechanical.com/services/index.php" target="_blank">http://www.pro-staffmechanical.com/services/index...
the COP it is the more effective when choose the correct chiller
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1 reply · active 299 weeks ago
Thanks for sharing you know regarding ac. It is very-2 helpful for me i'm making career in <a href="http://mycleanhut.com/services.php?cat_id=MTA=&category=AC+Services">AC service in chandiragh. your technical know is tips by tips so good .

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I never knew the difference. Thanks for sharing Absorption Chillers vs Electric Chillers.
Evaporative Cooling

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