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billhuntersemail(at)gmail
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 Posted: Tue Jan 03, 2017 6:23 pm Post subject: EMI From Seat Heaters and Other Questions |
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Hi AeroElectric Cyber Friends!!!
I figured I would bounce these questions off of the folks on this forum.
Over at the Velocity Aircraft Forum we have some questions with respect to EMI from 12 VDC supplemental cabin heat systems such as heated seats, heated blankets (such as an electric blanket that you plug into the cigarette lighter), and/or a 12 volt electric heating element heater.
QUESTION 1: Would the heat blanket/seat system affect the magnetometer on the aircraft? The 12 VDC electric heater has a motor and an element so that certainly might cause issues. If so how far away would you consider it the reasonable distance from the magnetometer to the heated element in the blanket/seat?
QUESTION 2: If the heated seat would cause EMI, is it possible to mitigate the EMI by “polarizing” the seat inserts (placing one element in one direction and the other in the opposite direction? This is the heated seat kit I bought for my aircraft: https://www.amazon.com/Water-Carbon-Premium-Heated-Seats/dp/B00AKEVNP2/ref=sr_1_10?ie=UTF8&qid=1483494619&sr=8-10&keywords=car%2Bheated%2Bseats&th=1
QUESTION 3: Would an electric seat/blanket cause radio noise? If so what can one do to mitigate the noise?
QUESTION 4: How much heat would a small 12 VDC electric element heater system realistically put out? This is the one we have been discussing it is designed for a RV unit: http://www.my12voltstore.com/12_Volt_Ducted_Heater_p/sd12-4000.htm
Does anybody happen to have any experience with this particular unit and to see if it’s worth the cost / weight penalty involved in hauling this thing around. I was thinking of installing this under the instrument panel and using it as a defroster by directing the “heated” air toward the windshield.
We are in a “heated discussion” on how to add a heat source to the airplane. The only heat in the velocity airplane design is an oil cooler mounted in the nose and that air/oil heat exchanger is used for cabin heat…the problem being that outside air is blown through the oil cooler and into the cabin and naturally during cold months the OAT is significantly cold and therefore the heat increase is not very efficient plus the fact that our air cooled engines may not be producing that much oil temperature to begin with so we are dreaming of ways to supplement our interior heat.
Any suggestions/feedback/experience would be greatly appreciated!!!
THANKS!!!
Bill Hunter
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edpav8r(at)yahoo.com
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| Posted: Tue Jan 03, 2017 8:52 pm Post subject: EMI From Seat Heaters and Other Questions |
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On Jan 3, 2017, at 6:20 PM, William Hunter <billhuntersemail(at)gmail.com (billhuntersemail(at)gmail.com)> wrote:
At the risk of being pedantic, I'm not sure how one would answer this other than to quote the product's specifications and explain the units.
The description says this heater rated for 8,016 British Thermal Units (BTUs). A BTU is the amount of energy it takes to heat one pound of water (about 16 fl oz, or two cups) by one degree Fahrenheit.
So, the heat energy this thing puts out could heat a 4-ton tank of water (approx 960 US gal) by one deg F in one hour. Or, to use numbers that are a bit more meaningful, heat about 96 gal of water by 10 deg F in one hour. Still not a very helpful comparison.
The specs say it draws 480W (40A at 12V). It looks like the blower motor accounts for 15W (1.25A) of that total, which leaves 465W (38.75A) for the heating elements. That's a decent amount of heat, but compare that figure against a typical small domestic space heater that we're all familiar with: they're commonly rated at 1,500W. The first three search results for "hair dryer" on Amazon are rated at 1,875W!
Recommendations vary between 20 and 60 BTU/sq ft for heating a home, depending on your climate region. If you assume a middle value of 40 BTU/sq ft, then 8,000 BTU would be about right for a 200 sq ft room (in a home insulated to code).
Whether that kind of analysis translates to airplanes, or if 8,000 BTU is adequate for a light plane cockpit flying through freezing air are interesting questions. How warm is warm enough?
Eric
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alec(at)alecmyers.com
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| Posted: Wed Jan 04, 2017 4:31 am Post subject: EMI From Seat Heaters and Other Questions |
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Someone has their units mixed up here. BTU is a measure of energy. Heaters are measured in BTU/hour. (Like the difference between joules and watts). 480W is 1638BTU/h, and 8000BTU/h is 2344W so the two figures given don't seem to agree. The former seems more reasonable than the latter for this unit.
On Jan 3, 2017, at 23:50, Eric Page <edpav8r(at)yahoo.com (edpav8r(at)yahoo.com)> wrote:
On Jan 3, 2017, at 6:20 PM, William Hunter <billhuntersemail(at)gmail.com (billhuntersemail(at)gmail.com)> wrote:
At the risk of being pedantic, I'm not sure how one would answer this other than to quote the product's specifications and explain the units.
The description says this heater rated for 8,016 British Thermal Units (BTUs). A BTU is the amount of energy it takes to heat one pound of water (about 16 fl oz, or two cups) by one degree Fahrenheit.
So, the heat energy this thing puts out could heat a 4-ton tank of water (approx 960 US gal) by one deg F in one hour. Or, to use numbers that are a bit more meaningful, heat about 96 gal of water by 10 deg F in one hour. Still not a very helpful comparison.
The specs say it draws 480W (40A at 12V). It looks like the blower motor accounts for 15W (1.25A) of that total, which leaves 465W (38.75A) for the heating elements. That's a decent amount of heat, but compare that figure against a typical small domestic space heater that we're all familiar with: they're commonly rated at 1,500W. The first three search results for "hair dryer" on Amazon are rated at 1,875W!
Recommendations vary between 20 and 60 BTU/sq ft for heating a home, depending on your climate region. If you assume a middle value of 40 BTU/sq ft, then 8,000 BTU would be about right for a 200 sq ft room (in a home insulated to code).
Whether that kind of analysis translates to airplanes, or if 8,000 BTU is adequate for a light plane cockpit flying through freezing air are interesting questions. How warm is warm enough?
Eric
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alec(at)alecmyers.com
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| Posted: Wed Jan 04, 2017 4:42 am Post subject: EMI From Seat Heaters and Other Questions |
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One might also point out that trying to heat a space from a 12v supply is like filling a swimming pool from a garden hose. Don't expect too much - there's a reason that where the aviation community can't use exhaust muff heating systems (cabin twins, for instance) they don't try electric, they use Janitrol heaters.
On Jan 3, 2017, at 23:50, Eric Page <edpav8r(at)yahoo.com (edpav8r(at)yahoo.com)> wrote:
On Jan 3, 2017, at 6:20 PM, William Hunter <billhuntersemail(at)gmail.com (billhuntersemail(at)gmail.com)> wrote:
At the risk of being pedantic, I'm not sure how one would answer this other than to quote the product's specifications and explain the units.
The description says this heater rated for 8,016 British Thermal Units (BTUs). A BTU is the amount of energy it takes to heat one pound of water (about 16 fl oz, or two cups) by one degree Fahrenheit.
So, the heat energy this thing puts out could heat a 4-ton tank of water (approx 960 US gal) by one deg F in one hour. Or, to use numbers that are a bit more meaningful, heat about 96 gal of water by 10 deg F in one hour. Still not a very helpful comparison.
The specs say it draws 480W (40A at 12V). It looks like the blower motor accounts for 15W (1.25A) of that total, which leaves 465W (38.75A) for the heating elements. That's a decent amount of heat, but compare that figure against a typical small domestic space heater that we're all familiar with: they're commonly rated at 1,500W. The first three search results for "hair dryer" on Amazon are rated at 1,875W!
Recommendations vary between 20 and 60 BTU/sq ft for heating a home, depending on your climate region. If you assume a middle value of 40 BTU/sq ft, then 8,000 BTU would be about right for a 200 sq ft room (in a home insulated to code).
Whether that kind of analysis translates to airplanes, or if 8,000 BTU is adequate for a light plane cockpit flying through freezing air are interesting questions. How warm is warm enough?
Eric
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alec(at)alecmyers.com
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| Posted: Wed Jan 04, 2017 5:07 am Post subject: EMI From Seat Heaters and Other Questions |
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Last post for now, I promise: the Janitrol approved for installation in a (4 seat) Cessna 170 is 25000BTU/h which is 7.3kW. Compare 500w...
On Jan 4, 2017, at 07:41, Alec Myers <alec(at)alecmyers.com (alec(at)alecmyers.com)> wrote:
One might also point out that trying to heat a space from a 12v supply is like filling a swimming pool from a garden hose. Don't expect too much - there's a reason that where the aviation community can't use exhaust muff heating systems (cabin twins, for instance) they don't try electric, they use Janitrol heaters.
On Jan 3, 2017, at 23:50, Eric Page <edpav8r(at)yahoo.com (edpav8r(at)yahoo.com)> wrote:
On Jan 3, 2017, at 6:20 PM, William Hunter <billhuntersemail(at)gmail.com (billhuntersemail(at)gmail.com)> wrote:
At the risk of being pedantic, I'm not sure how one would answer this other than to quote the product's specifications and explain the units.
The description says this heater rated for 8,016 British Thermal Units (BTUs). A BTU is the amount of energy it takes to heat one pound of water (about 16 fl oz, or two cups) by one degree Fahrenheit.
So, the heat energy this thing puts out could heat a 4-ton tank of water (approx 960 US gal) by one deg F in one hour. Or, to use numbers that are a bit more meaningful, heat about 96 gal of water by 10 deg F in one hour. Still not a very helpful comparison.
The specs say it draws 480W (40A at 12V). It looks like the blower motor accounts for 15W (1.25A) of that total, which leaves 465W (38.75A) for the heating elements. That's a decent amount of heat, but compare that figure against a typical small domestic space heater that we're all familiar with: they're commonly rated at 1,500W. The first three search results for "hair dryer" on Amazon are rated at 1,875W!
Recommendations vary between 20 and 60 BTU/sq ft for heating a home, depending on your climate region. If you assume a middle value of 40 BTU/sq ft, then 8,000 BTU would be about right for a 200 sq ft room (in a home insulated to code).
Whether that kind of analysis translates to airplanes, or if 8,000 BTU is adequate for a light plane cockpit flying through freezing air are interesting questions. How warm is warm enough?
Eric
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bakerocb
Joined: 15 Jan 2006
Posts: 727
Location: FAIRFAX VA
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| Posted: Wed Jan 04, 2017 2:22 pm Post subject: EMI From Seat Heaters and Other Questions |
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1/4/2017
Hello Bill Hunter, I could not find enough space under the engine cowling to put a heat muff on the exhaust system of my KIS TR-1 airplane powered by a Continental Motors IO-240 B9B engine.
I initially tried to use an recreational vehicle heater similar to your:
http://www.my12voltstore.com/12_Volt_Ducted_Heater_p/sd12-4000.htm
It generated about as much heat as waving a lighted cigarette around in the cockpit. Also it generated noise on the radio. Totally useless.
My solution was electrically heated clothing like the motorcyclists and the snowmobile riders use. My brand was Gerbings bought several years ago which has worked great. That company’s recent history is shaky so shop around before you buy.
OC
=======================================
Time: 06:23:06 PM PST US
From: "William Hunter" <billhuntersemail(at)gmail.com>
Subject: EMI From Seat Heaters and Other Questions
Hi AeroElectric Cyber Friends!!!
I figured I would bounce these questions off of the folks on this forum.
Over at the Velocity Aircraft Forum we have some questions with respect to
EMI from 12 VDC supplemental cabin heat systems such as heated seats, heated
blankets (such as an electric blanket that you plug into the cigarette
lighter), and/or a 12 volt electric heating element heater.
QUESTION 1: Would the heat blanket/seat system affect the magnetometer on
the aircraft? The 12 VDC electric heater has a motor and an element so that
certainly might cause issues. If so how far away would you consider it the
reasonable distance from the magnetometer to the heated element in the
blanket/seat?
QUESTION 2: If the heated seat would cause EMI, is it possible to mitigate
the EMI by "polarizing" the seat inserts (placing one element in one
direction and the other in the opposite direction? This is the heated seat
kit I bought for my aircraft:
<https://www.amazon.com/Water-Carbon-Premium-Heated-Seats/dp/B00AKEVNP2/ref
sr_1_10?ie=UTF8&qid=1483494619&sr=8-10&keywords=car%2Bheated%2Bseats&th=1>
https://www.amazon.com/Water-Carbon-Premium-Heated-Seats/dp/B00AKEVNP2/ref=s
r_1_10?ie=UTF8&qid=1483494619&sr=8-10&keywords=car%2Bheated%2Bseats&th=1
QUESTION 3: Would an electric seat/blanket cause radio noise? If so what
can one do to mitigate the noise?
QUESTION 4: How much heat would a small 12 VDC electric element heater
system realistically put out? This is the one we have been discussing it is
designed for a RV unit:
<http://www.my12voltstore.com/12_Volt_Ducted_Heater_p/sd12-4000.htm>
http://www.my12voltstore.com/12_Volt_Ducted_Heater_p/sd12-4000.htm
Does anybody happen to have any experience with this particular unit and to
see if it's worth the cost / weight penalty involved in hauling this thing
around. I was thinking of installing this under the instrument panel and
using it as a defroster by directing the "heated" air toward the windshield.
We are in a "heated discussion" on how to add a heat source to the airplane.
The only heat in the velocity airplane design is an oil cooler mounted in
the nose and that air/oil heat exchanger is used for cabin heat.the problem
being that outside air is blown through the oil cooler and into the cabin
and naturally during cold months the OAT is significantly cold and therefore
the heat increase is not very efficient plus the fact that our air cooled
engines may not be producing that much oil temperature to begin with so we
are dreaming of ways to supplement our interior heat.
Any suggestions/feedback/experience would be greatly appreciated!!!
THANKS!!!
Bill Hunter
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billhuntersemail(at)gmail
Guest
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| Posted: Wed Jan 04, 2017 3:32 pm Post subject: EMI From Seat Heaters and Other Questions |
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Thanks All for your time in contributing to this subject. I certainly came to the right place.
DANG…and I thought that a “BTU” was a form of currency changing because I see BTU on my utility bill and my currency changes from my account to the utility company account.
..
Cheers!!!
Bill Hunter
From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Alec Myers
Sent: Wednesday, January 4, 2017 4:31 AM
To: aeroelectric-list(at)matronics.com
Subject: Re: EMI From Seat Heaters and Other Questions
Someone has their units mixed up here. BTU is a measure of energy. Heaters are measured in BTU/hour. (Like the difference between joules and watts). 480W is 1638BTU/h, and 8000BTU/h is 2344W so the two figures given don't seem to agree. The former seems more reasonable than the latter for this unit.
On Jan 3, 2017, at 23:50, Eric Page <edpav8r(at)yahoo.com (edpav8r(at)yahoo.com)> wrote:
On Jan 3, 2017, at 6:20 PM, William Hunter <billhuntersemail(at)gmail.com (billhuntersemail(at)gmail.com)> wrote:
At the risk of being pedantic, I'm not sure how one would answer this other than to quote the product's specifications and explain the units.
The description says this heater rated for 8,016 British Thermal Units (BTUs). A BTU is the amount of energy it takes to heat one pound of water (about 16 fl oz, or two cups) by one degree Fahrenheit.
So, the heat energy this thing puts out could heat a 4-ton tank of water (approx 960 US gal) by one deg F in one hour. Or, to use numbers that are a bit more meaningful, heat about 96 gal of water by 10 deg F in one hour. Still not a very helpful comparison.
The specs say it draws 480W (40A at 12V). It looks like the blower motor accounts for 15W (1.25A) of that total, which leaves 465W (38.75A) for the heating elements. That's a decent amount of heat, but compare that figure against a typical small domestic space heater that we're all familiar with: they're commonly rated at 1,500W. The first three search results for "hair dryer" on Amazon are rated at 1,875W!
Recommendations vary between 20 and 60 BTU/sq ft for heating a home, depending on your climate region. If you assume a middle value of 40 BTU/sq ft, then 8,000 BTU would be about right for a 200 sq ft room (in a home insulated to code).
Whether that kind of analysis translates to airplanes, or if 8,000 BTU is adequate for a light plane cockpit flying through freezing air are interesting questions. How warm is warm enough?
Eric
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ceengland7(at)gmail.com
Guest
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| Posted: Wed Jan 04, 2017 4:52 pm Post subject: EMI From Seat Heaters and Other Questions |
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Well....That's kinda comparing apples to kumquats.
Ever driven a late model car with seat heaters? Hop in on a freezing cold day, crank the engine, and with the seat heaters on, your body will be warm before the engine coolant has gone up 2 degrees. All the heat goes directly to your body core.
As an analogy, consider the radiant heaters used in a lot of workshops. As long as they are pointed at the worker, the worker stays reasonably warm even though the shop's air temp stays cold.
I suspect that twins had Janitrol heaters long before heated seats were invented, or even a possibility (many generators from that era could barely keep up with the electrical demands of the instrument panel). And the current crop of cabin twins have them because those that can afford them expect them to offer all the comforts of home; hang the expense and inefficiency.
Charlie
On 1/4/2017 6:41 AM, Alec Myers wrote:
| Quote: | One might also point out that trying to heat a space from a 12v supply is like filling a swimming pool from a garden hose. Don't expect too much - there's a reason that where the aviation community can't use exhaust muff heating systems (cabin twins, for instance) they don't try electric, they use Janitrol heaters.
On Jan 3, 2017, at 23:50, Eric Page <edpav8r(at)yahoo.com (edpav8r(at)yahoo.com)> wrote:
On Jan 3, 2017, at 6:20 PM, William Hunter <billhuntersemail(at)gmail.com (billhuntersemail(at)gmail.com)> wrote:
At the risk of being pedantic, I'm not sure how one would answer this other than to quote the product's specifications and explain the units.
The description says this heater rated for 8,016 British Thermal Units (BTUs). A BTU is the amount of energy it takes to heat one pound of water (about 16 fl oz, or two cups) by one degree Fahrenheit.
So, the heat energy this thing puts out could heat a 4-ton tank of water (approx 960 US gal) by one deg F in one hour. Or, to use numbers that are a bit more meaningful, heat about 96 gal of water by 10 deg F in one hour. Still not a very helpful comparison.
The specs say it draws 480W (40A at 12V). It looks like the blower motor accounts for 15W (1.25A) of that total, which leaves 465W (38.75A) for the heating elements. That's a decent amount of heat, but compare that figure against a typical small domestic space heater that we're all familiar with: they're commonly rated at 1,500W. The first three search results for "hair dryer" on Amazon are rated at 1,875W!
Recommendations vary between 20 and 60 BTU/sq ft for heating a home, depending on your climate region. If you assume a middle value of 40 BTU/sq ft, then 8,000 BTU would be about right for a 200 sq ft room (in a home insulated to code).
Whether that kind of analysis translates to airplanes, or if 8,000 BTU is adequate for a light plane cockpit flying through freezing air are interesting questions. How warm is warm enough?
Eric
|
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ornerycuss2001(at)yahoo.c
Guest
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| Posted: Wed Jan 04, 2017 9:18 pm Post subject: EMI From Seat Heaters and Other Questions |
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Have you considered a door in the fresh air inlet to the air-oil cooler and an alternate air path to recycle cabin air through the air-oil cooler?
--------------------------------------------
On Wed, 1/4/17, William Hunter <billhuntersemail(at)gmail.com> wrote:
Subject: RE: EMI From Seat Heaters and Other Questions
To: aeroelectric-list(at)matronics.com
Date: Wednesday, January 4, 2017, 3:31 PM
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#yiv3929019256 Thanks All for your time in
contributing to this subject. I certainly came to the
right place. DANG…and I thought that a
“BTU” was a form of currency changing because I see BTU
on my utility bill and my currency changes from my account
to the utility company account...
Cheers!!!
Bill Hunter
From:
owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On
Behalf Of Alec Myers
Sent:
Wednesday, January 4, 2017 4:31 AM
To: aeroelectric-list(at)matronics.com
Subject: Re: EMI From
Seat Heaters and Other Questions Someone has their units mixed
up here. BTU is a measure of energy. Heaters are measured in
BTU/hour. (Like the difference between joules and watts).
480W is 1638BTU/h, and 8000BTU/h is 2344W so the two figures
given don't seem to agree. The former seems more
reasonable than the latter for this unit.
On Jan 3,
2017, at 23:50, Eric Page <edpav8r(at)yahoo.com>
wrote:On Jan 3, 2017, at 6:20 PM,
William Hunter <billhuntersemail(at)gmail.com>
wrote:QUESTION 4: How much heat would
a small 12 VDC
electric element heater
system realistically put out? This is
the one we have been discussing it is designed for a RV
unit: http://www.my12voltstore.com/12_Volt_Ducted_Heater_p/sd12-4000.htm At the risk of being
pedantic, I'm not sure how one would answer this other
than to quote the product's specifications and explain
the units.
The
description says this heater rated for 8,016 British Thermal
Units (BTUs). A BTU is the amount of energy it takes to
heat one pound of water (about 16 fl oz, or two cups) by one
degree Fahrenheit. So, the heat energy this
thing puts out could heat a 4-ton tank of water (approx 960
US gal) by one deg F in one hour. Or, to use numbers that
are a bit more meaningful, heat about 96 gal of water by 10
deg F in one hour. Still not a very helpful
comparison.
The specs
say it draws 480W (40A at 12V). It looks like the blower
motor accounts for 15W (1.25A) of that total, which leaves
465W (38.75A) for the heating elements. That's a
decent amount of heat, but compare that figure against a
typical small domestic space heater that we're all
familiar with: they're commonly rated at 1,500W. The
first three search results for "hair dryer" on
Amazon are rated at 1,875W! Recommendations vary between
20 and 60 BTU/sq ft for heating a home, depending on your
climate region. If you assume a middle value of 40 BTU/sq
ft, then 8,000 BTU would be about right for a 200 sq ft room
(in a home insulated to code). Whether that kind of analysis
translates to airplanes, or if 8,000 BTU is adequate for a
light plane cockpit flying through freezing air are
interesting questions. How warm is warm
enough?
Eric
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