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metal halide ballasts
> From: "Michael A. Bateman" <spine at stlnet_com>
> Date: Sat, 15 Mar 1997 10:50:14 -0600
> Subject: New IceCap MH Ballasts
> For those of you using MH lighting or are considering it, IceCap
> Industries has a new Electronic Metal Halide ballast. They make some
> pretty amazing claims and after talking to them on the phone about
> it, they have me convinced to give the new product a try. I know my
> current MH ballasts run quite hot and as a user of their VHO ballast
> (which lives up to all of its claims) I'm excited about this new
> product. Aqualink Direct is selling them for $169 for a single lamp
> ballast. The following is a list of their claims.
It is unlikely that high frequency operation increases the efficiency of
a metal halide lamp. The arc tube is too short. Therefore, most of the
gains are probably in ballast efficiency. Let's assume that the icecap
ballast is 100% efficient, and the ballast losses for a 175 watt metal
halide are 20% of the nominal power of the lamp (which is about right.)
Cost to run a traditional 175 watt metal halide for a year, total
energy consumption 210 watts, 10 hours per day
.21 kW * 0.12 dollars/kWhr * 3650 hours per year = $91.98
Cost to run a 100% efficient ballast + 175 watt lamp, total energy
consumption 175 watts, 10 hours per day
0.175 kW * 0.12 dollars/kW hr * 3650 hours per year = $76.65
for a whopping savings of: $15.33 per year.
Advertized cost per ballast is $169. Time to pay back ballast cost,
11.0 years. Equivalent interest rate, 9.1%. You will do a lot better in
the stock market.
It looks a little better on a new installation, where you don't have to
discard an old core and coil or potted ballast. Assuming a traditional
ballast cost of $50, the payback time on a new installation is 7.7
years. Equivalent interest rate, 12.9%.
If they can show real increases in lamp life, the ballasts will look a
lot better. The reason that I'm dubious about that is that part of the
decay of a metal halide lamp has to to with high temperature chemistry,
and it isn't immediately obvious to me how high frequency operation is
going to affect that.