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Estimating Compressor price based on HP

Estimating Compressor price based on HP

Estimating Compressor price based on HP

(OP)
Hi All

Is there any criteria to evaluate compressor price based on its power thumb of rule ? How about Gas Turbine? or Electrical Motor?

RE: Estimating Compressor price based on HP

Sure there's ways. Most of them either: (1) have a shelf life of a few weeks; or (2) never had any validity at all. If you are just looking at the compressor (not the driver, intercooler, aftercooler, separation, skid, piping, etc) then the numbers are fairly stable and you can get a quote on a big compressor and a quote on a small compressor, turn both numbers into a cost/hp (or a cost/max volume) average the results and get a number that is +/-50% for intermediate units. But so what? Unless you are a packager the cost of the air-end is a tiny fraction of the total cost.

Package costs are a lot more difficult. The cost of Engineering is similar for small units or large units. The cost of the structural elements is about the same. The cost of control equipment is relatively constant. The cost of labor is a rough function of the number of components. Packagers profit margin is an unknown quantity. The cost of any vessels and coolers can be related to mass flow rate reasonably easily. Driver size is a function of mass flow rate and compression ratios. Throw all that together and get a price of (say) $837/hp for recips and $652/hp for oil flooded screws and $1258/hp for gas turbine driven centrifugals. Those numbers are just made up, but if I had looked closely at 35 projects of various sizes and scientifically combined them into those numbers they would be reasonably representative for the equipment from those manufacturers and that packager. A new bid the next day that changed from Frick screws to Kobelco screws (both process-derivitive oil flooded screws) or from Toromont to Exterran for packaging and the estimate may not be within 60% of my projected cost/hp number.

I have found that for similar hp from the same packager at any given time that recips tend to cost about 20-30% more per hp than flooded screws. I've also found that if I send a bid to one packager for a recip and another packager for a screw that sometimes the screw from packager "B" is more expensive than the recip from packager "A".

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

RE: Estimating Compressor price based on HP

Speaking with regard to recip packages, there is some economy of scale with regard to $$/BHP. I work for a compressor OEM and I have two vary vague, general "rules of thumb" $750/BHP (Higher 850-$1000/HP for smaller applications and slightly lower for larger HP applicaton) and 2) 4-5x compressor price.
High spec applications can obviously throw these "rules of thumb" way out of whack.

I do not know enough about our centrifugal business to give a rule of thumb. I would definitely price them higher than recips though.

RE: Estimating Compressor price based on HP

With so many variables in applications I believe you will find, as zdas04 and BNiessing have indicated, historical data based on application may be the best baseline. Of course, economic climate will significantly impact just about everything.

If you are dealing with production pre-engineered applications you may be able to develop a power or capacity correlation to price. Introducing engineering into the equation and supplier backlog provides for the scenarios already posted – market forces shall prevail.

In previous a life previous life in Applications for an OEM I worked with several end users to develop price scales for specific processes. Depending on the application you may find that not all OEMs/packagers are equal – in price and of course quality. It was rare, if ever, that a best fit throughout a large range is available from a sole source, but it is possible. Your task may fit the products of brand X like a glove, or the process may be able to be adjusted to a cost effective product.

Good luck.

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