Wednesday, November 26, 2014

Selecting Energy Efficient Centrifugal Pumps


Centrifugal pumps handle high flow rates, provide smooth, nonpulsating delivery,
and regulate the flow rate over a wide range without damaging the pump. Centrifugal
pumps have few moving parts, and the wear caused by normal operation is minimal.
They are also compact and easily disassembled for maintenance.

The efficiency of  pumping system depends on relationships between fluid flow rate, piping
layout, control methodology, and pump selection. Selection of a centrifugal pump is
based on  its application.

Centrifugal Pump Performance

Centrifugal pumps are generally divided into three classes: radial flow, mixed flow,
and axial flow. Impeller design variations can be used to design specific pumps that  perform efficiently under specified conditions that vary from low flow rate with high head to high flow rate with low head. The amount of fluid a centrifugal pump moves depends on the differential
pressure or head it supplies. The flow rate increases as the head decreases.

Manufacturers  provide information on  range of heads and flow rates that a particular pump model can provide.

Before you select a pump model, examine its performance curve, which is indicated by
its head-flow rate or operating curve. The curve shows the pump’s capacity (in gallons
per minute [gpm]) plotted against total developed head (in feet). It also shows efficiency
(percentage), required power input (in brake-horsepower [bhp]), and suction head
requirements (net positive suction head requirement in feet) over a range of flow rates.
Pump curves also indicate pump size and type, operating speed (in revolutions per
minute), and impeller size (in inches). It also shows the pump’s best efficiency point (BEP).
The pump operates most cost effectively when the operating point is close to the BEP.

Pumps can generally be ordered with a variety of impeller sizes. Each impeller has a
separate performance curve  To minimize pumping system energy
consumption, select a pump so the system requirement is within 20% of pump's
BEP, and select a mid range impeller that can be trimmed or replaced to meet higher or
lower flow rate requirements.Select a pump with high efficiency contours over your
range of expected operating points. A few points of efficiency improvement can
save significant energy over the life of the pump.

Wednesday, November 19, 2014

Hydrogen Cars

19 November

Audi unveiled the A7 h-tron quattro with hydrogen fuel cell that will go over 300 miles between refuellings. At the moment it is only a demonstration car. But Audi says it can deliver production version whenever infrastructure is ready for hydrogen supply.

18 November 2014

Now hydrogen cars available for commercial use.

Hyundai has been leasing the hydrogen-powered Tucson sport utility, which it describes as the world’s first mass-produced fuel cell car, since June, for a $2,999 down payment, and $499 a month. (That includes the hydrogen.)

Toyota is introducing a sedan called Mirai, which means “future” in Japanese.

The Mirai will go on sale in California this year for $57,500 — cheaper than the Tesla Model S.

News about Mirai

Japan Launch Event for Mirai Fuel Cell Sedan

Toyota Global News Room

Akiyo Toyoda on Mirai
2.4 minutes

Toyota Global Newsroom

How fuel cells work?

Friday, November 14, 2014

Ten Types of Smart Engineering - 2013

Need‐of‐the‐Hour Engineering:
Improvised Engineering:
Strip‐Down Engineering:
Performance‐Boosting Engineering:
IntelliSys Engineering:  
Cross‐Pollination Engineering:
Smart‐Auxiliary Engineering:
Sustainable Engineering:
Nature‐Inspired Engineering:
Forward‐Looking Engineering:

Dr. Aloknath De, SrVP and CTO, Samsung India‐Bangalore