Subject: Re: Cogeneration

From: [email-masked] (Nick Pine)
Date: 28 Sep 1995 06:24:04 -0400

Bob Apthorpe <[email-masked]> wrote:
 
>Cogeneration is becoming more popular and will continue until market forces
>make it noncompetitive. Still, this is currently only feasible for large
>consumers such as chemical plants and paper mills.

Gee, my Pennsylvania customer didn't mention that he had a paper mill in
the basement :-) The local electric utility has now approved the application
for the first Intelligen system in Pennsylvania. 

Article: 1086 of sci.engr.heat-vent-ac
From: [email-masked] (Nick Pine)
Subject: Intelligen's 5 kW cogenerator
Date: 11 Jul 1995 06:56:04 -0400
Organization: Villanova University

Do the people in this group mostly already know about Intelligen's 5 kW
residential cogeneration system? Someone in the alternate energy newsgroup
requested that their address be posted, so I'll post some info here too...

Intelligen Energy Systems       Tom Sciacca, President
58 South Street                 Neil Slavin, Exec. VP
Hopkinton, MA 01748             (508) 435-9007

This is a clever "oil burner," that costs about $10K, but it can pay for itself
in 3-5 years, vs. the infinite payback period for an ordinary oil burner, by
making 5 kW of electricity while it is heating a house. The interface is an
ordinary circuit breaker in the service panel, the kind you would use for an
electric range.

Burning home heating oil, it's pretty efficient. About 93%, with a 1 1/2"
PVC fluepipe and a 150F exhaust gas temperature. Inside the 800 lb box is
an extremely reliable 11 HP diesel made by Lister-Petter, and an induction
generator. When the house thermostat calls for heat, the induction generator
acts as a motor to start the diesel from the 220 volt line. Then it becomes
a generator, making the meter run backwards, if legally permitted. (In some
states, you need two meters. In Pennsylvania, small power producers with
efficient (FERC certified) systems are paid at the retail rate for the power
they make, until their net monthly electrical consumption reaches zero, at
which point, the utility begins to pay a lower "avoided cost" per kWh. In
winter months, a typical house generates two or three times its electrical
needs, and the utility sends the owner a check, versus vice versa.) When
the house is warm enough, the diesel engine stops running.

Of course you have to put sandbags all over the kitchen floor, to keep the
dishes from rattling off the shelves... :-) No, it's actually fairly quiet,
60 dBA 2 meters away, with good shock mounts as well as acoustic skins.

The unit has a built-in circulator pump, which runs the engine block cooling
water thru baseboard radiators, a duct heat exchanger, a fan coil unit, an
indirect-fired water heater, a hot tub or swimming pool heat exchanger, etc.
55,000 Btu/hr. 85,000, max, in "turbo-mode" :-) if the microprocessor senses
more heat is needed and diverts the electrical output to turn on some heaters
in the water stream, instead of feeding it back to the electric company.
(Don't ask how 5 kW makes 30K Btu/hour, perhaps there's a bug in the spec.)

The company has about three dozen systems installed in New England now,
interfaced with about ten utilities. They would like to expand their
territory. I'm helping them get the first one installed in Pennsylvania.

The unit won't work in a stand-alone power mode. It won't start without grid
power, and it won't stay running on a dead line. This is a "safety feature."

Most cogen systems are at least a thousand times bigger, 5 megawatts and up.
One of the big problems with these small systems is lifetime. Some standby
power systems spec oil changing every 25 hours. Others wear out in 2000 hours.
Intelligen's diesel engine is very reliable. It's also used in the M1 tank
(for auxiliary power), the DEW line, military jet engine starting systems,
commercial fishing fleets, and offshore Coast Guard installations that only
get visited once a year or so. Intelligen has a 10 year guarantee. Maintenance
consists of changing the oil once a year. And perhaps gently enquiring how
the unit has been doing over the last year, perhaps by telephone, via its
non-volatile RAM and RS-232 interface :-)

Nick

---

From: [email-masked] (Nick Pine)
Date: 8 Oct 1995 18:33:37 -0400

Kristjan Valur Jonsson <[email-masked]> wrote:
>[email-masked] (Gary Coffman) writes:
>>[email-masked] (Nick Pine) writes:

>>And an essential one, otherwise frying a lineman is a distinct possibility.
>
>Come on.  The utilities can easily adopt safer working methods.
>It's no harder than simply breaking the line on each side of the
>work side.  Simple really.

If I were a lineman, I would do that. Or treat a dead line as if it were
active, or could become so. Linemen do sometimes work on active lines,
sometimes on very high voltage lines, suspended by insulators in foil
suits to prevent corona damage, while they are charged up to hundreds
of thousands of volts...

>The argument about dead linemen is nonsense.

I do think that fear is overemphasized. I agree that there should be a fail
safe system that disconnects the cogen unit from the line, if the line
is dead, or makes it inoperable. Utilities generally accept that induction
generators excited by the grid are inherently safe. In fact, there is
a paragraph in the NEC to that effect. I'm sure these backwards lamp
dimmers could be made very safe too. 

Remember when you had to have all kinds of permits to connect something odd
to your telephone line, like an unapproved answering machine? Now,
post-Carterphone, it's pretty much your business what you do with your
phone line inside your house. It seems to me that that may happen soon
with electric lines. You don't have to tell the utility when you hook
up a 5 kW electric dryer or water heater. I see a time when you won't
have to tell them if you hook up a 100 watt synchronous inverter either...

Nick

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From: [email-masked] (Nick Pine)
Date: 23 Oct 1995 14:47:31 -0400

Jesus sticks sound like a very good idea. If I were a lineman, I'd use
'em on every job. Or maybe a couple of 12 V battery cables...

Nick

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From: [email-masked] (Nick Pine)
Date: 31 Oct 1995 01:09:53 -0500

Harry H Conover <[email-masked]> wrote:

>... home-based equipment in unlikely to meet the FAIL-SAFE
>requirement due to cost considerations (this is partularly true 
>of home type synchronous inverters which, analysis reveals, can
>readily self-excite).

Bullshit.

Nick