Energy Solutions Center–Technologies

Absorption Chillers

Applications

• Large Tonnage Space Cooling
• Industrial Process Cooling
• Cogen Waste Heat utilization
• Waste-to-Energy utilization
  

Overview

With the exception of very high cost electric areas, absorption chillers cost more to operate than electric chillers. They also cost about twice as much to purchase. Therefore, a reason other than average electric cost is needed to justify a base-loaded absorption system. Economics are more favorable for hybrid systems. Hybrid systems combine absorption chillers for use during on-peak electric hours and electric chillers for base load operation.

Steam-fired absorption is a good application where there is a low cost of steam such as a cogen or waste energy plant. Direct-fired natural gas units are used in hybrid and high-cost electricity areas. Absorption chillers do NOT use a CFC or HCFC refrigerant; therefore, some users purchase absorption chillers for this environmental advantage. Larger tonnages (above 500 tons) have a more favorable first cost when compared to electric technologies. Therefore, larger tonnage units are more common for absorption applications. They may also be used in places like campuses with a central steam loop and not enough electrical power distribution to run decentralize electric chillers. This may be the case where buildings either did not have chillers or used older single-effect absorption units and have upgraded to double-effect or direct fired absorption technology.

For more details....

Fluide Design Inc. - Tutorial - Centrifugal pump systems

This on-line tutorial is intended for everyone with an interest in centrifugal pumps. There is no math, just good, clear explanations of how it works. The tutorial contains the equivalent of about 50 typed 8 1/2"x11" pages with lots of images. The style is loose and stresses principles and understanding rather than details of calculations. For those who need to do those calculations, there are links to many pages that can be downloaded for this purpose as well. You will be given the opportunity of providing feedback or comments throughout the tutorial. Enjoy! There is more information available in the pdf version of this tutorial. Listen to the author's introductory comments on this audio recording .

This tutorial answers the following questions:

- What are the important characteristics of a pump system.

- What is head and how is it used in a pump system to make calculations easier.

- What is static head and friction head and how do they affect the flow rate in a pump system.

- How does a centrifugal pump produce pressure.

- Why is total head and flow the two most important characteristics of a centrifugal pump?

- What is meant by the pump rating? And what is the optimal operating point of a centrifugal pump?

- How to do details calculations that will allow you to size and select a centrifugal pump.

- How to verify that your centrifugal pump is providing the rated pressure or head.

- What is density and specific gravity and how do they relate to pressure and head?

For more details