HP sodium Lighting [RE-wrenches]

[Darryl Thayer]

Hello all
I would like to reinforce what Travis said.  In a
recient case I replaced a 18 watt LPS with a 13 watt
Compact florecent both running on 12 volts.  The many
customers ( this was a state park job) all said it was
brighter, and I thought it looked much brighter.  Of
the about 8 people that were there all said the
flourecent was at least twice as bright and they liked
it better.  With the LPS you can not see defination,
everything blends together.  
Darryl

--- "Travis Creswell, Ozark Solar" <ozsolar at ipa.net>
wrote:

> Hi Ray,
> 
> If you could, I'd avoid HPS and especially avoid
> LPS.  Yes, it does have the
> highest lumens per watt (LPW) but LPW does not
> completely reflect what our
> eyes see.
> 
> Color Rendering Index and Kelvin are also very
> important.  A CRI of 100 is
> perfect. IE; 100 out of 100 people will say they
> like it, halogen is the
> typical benchmark.  And it turns out that we feel
> the brightest light is
> somewhere around 5000 Kelvin.  HPS is approximately
> 2800 Kelvin with a CRI
> of less then 40.  IE less then 40 will approve of
> it.  The classic "cool
> white" fluorescent lamp is 4100 Kelvin and ~60 CRI
> and warm white is 3000k
> and ~60 CRI.
> 
> When you get into the tri-phosphor fluorescent the
> CRI approaches 90.
> 
> So what I am trying to say is people will actually
> think a 35 watt
> fluorescent is brighter then a 35 w HPS and that's
> what matters.  I've done
> hundreds of side by side comparisons for customers
> and every time they
> choose the fluorescent. A foot candle meter will say
> the opposite but it's
> not signing the checks, the customer is, so guess
> which one I pay more
> attention to.
> 
> In case you haven't figured out we do a ton of
> commercial and industrial
> lighting design and installation. (non-solar stuff)
> 
> 
> I don't know about requiring pure sine wave.
> 
> The HID (high intensity discharge, HPS, MH, MV, ETC)
> ballasts I've measured
> have no start up surge.  As the light warms up the
> current climbs to it's
> rated running current.
> 
> The HPS lamps in that size range are likely more
> expensive to replace than
> fluorescent.
> 
> Best,
> 
> Travis Creswell
> Ozark Energy Services
> 
> 
> 
> 
> 
> 
> 
> -----Original Message-----
> From: Ray Walters [mailto:walters at taosnet.com] 
> Sent: Wednesday, February 01, 2006 3:27 PM
> To: RE-wrenches at topica.com
> Subject: HP sodium Lighting [RE-wrenches]
> 
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> 
> Hi Wrenches;
> 
> I'm doing a small lighting project for the
> University of New Mexico. It 
> will be a demonstration for future students, as well
> as a hands-on 
> installation for my current class. We are proposing
> using Bollard type ( 
> 3 ft pedestal lights for along sidewalks, etc.). The
> only reasonably 
> priced units are AC, and are High pressure Sodium.
> HPS lighting is as 
> efficient or more so than fluorescents, but I'm
> concerned about  the 
> inverter for HPS lighting. MY questions:
> 1) Do HP sodium light ballasts require pure sine
> wave?
> 2) How much surge capacity do their ballasts require
> to start (35 watt 
> light), worst case scenario, ie.  very cold, very
> hot, etc.
> 3) Anybody have a good source for DC bollards maybe?
> 
> We found a site that had DC LED Bollards (wow!) but
> alas it was european 
> and not available here.
> 
> Thanks for sharing your wealth of knowledge,
> 
> Ray Walters
> 
> 
> 
> 
> 
> 
> 


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