John,
? ? ? ? ?I have a C3 31. If you have not used the thicknesser for four or five days, it will not be happy until you clean and lubricate the table. If the material is even slightly damp, forget it until the table is really clean.
Trevor Lusty
Ireland?
|
Re: Building a closet for dust collector
Well, I can quantify this¡ a couple of houses ago, I had a 25x35 shop with 8¡¯ ceilings, built out of Integra block (very hollow block with poly foam sprayed in the cavities), then insulated with 1 1/2¡± more foam ?as I furred out before the drywall. I had the 1.5hp Oneida DC set in the adjacent garage and originally had the exhaust empty into the garage. I found that in the summer with the A/C set to 80?, I could turn on the DC and suck all the cool air out of the shop in about 5 minutes, the temp would rise to about 90? and 3 tons of AC couldn¡¯t cool it down.?
So, I had to revise the plan and poke a hole in the wall and re-route the exhaust back into the shop. Even with that, the time the air spent in the warmer garage caused the AC unit to labor much more than the times when the DC wasn¡¯t running. AC unit was on a 40 amp breaker¡ doesn¡¯t take long to burn through a lot of $$$$ running that kind of amperage.
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Show quoted text
On May 23, 2020, at 10:22 AM, mark thomas < murkyd@...> wrote:
On Sat, May 23, 2020 at 09:22 AM, Brian Lamb wrote:
In AZ where we have massive heat loads in the summer, exhausting air outside is a foolish endeavor
Maybe, but foolish is relative.? My point is that it might be worth quantifying, since everything is a tradeoff. For exampling, using my previous estimate of costing $2.50/hr to make up for lost DC exhaust cooling, that might be a very "foolish" loss rate for 24x7 operation like a house ($18k/year), but less foolish for a DC running an hour per day ($900/yr) One could say it's foolish to have a 2400 sq ft shop.? Or maybe 2400 ft the sweet spot, and 5,000 ft is foolish.? Or foolish to set themostat at 68 instead of 75.? ?Or foolish to spend $200k on hobby equipment.?? Some people think it's foolish that humans inhabited Arizona.?? I'm just saying, without some attempt to quantify and put it into one's personal context, just declaring it infeasible or foolish seems not very well grounded.
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Re: Building a closet for dust collector
This is my last post ¨C too much time typing and not in the shop today.
?
Your 2-ton AC unit can remove about 24,000 BTU of heat, which translates to about 7KW worth of continuous energy removal ability, and potentially quite a bit more than that in terms of handling intermittent load. I also have a 5HP Clearvue
Cyclone and it draws about 18 amps at 240 volts, which is about 4KW or so. That leaves 3KW of continuous load plus whatever time your cyclone is off (which I suspect is most of the time) to handle the intermittent tools as well as the environmental factors.
I¡¯m not surprised it works for you.
?
Calculating the heat loss of your other building is not trivial due to differences in construction thermal mass of the stuff in there, etc. You didn¡¯t specify how many people are working in your shop or what your duty cycle is. If you had
5 people using each of your machines full-time I have no doubt you would need to open the windows even in the winter due to too much heat. If it¡¯s just you and you run one machine occasionally plus your dust collector, that¡¯s maybe 3KW average draw, or the
equivalent of about 2 1500w space heaters. If you are bored enough to want to run this down, next time you are there keep track of how often your power tools are actually running. I bet it¡¯s less often than you think.
?
My shop is also about 600 sq ft, is insulated, and as mentioned earlier, in Minnesota. When I run my vacuum hold down table, Clearvue DC, and my CNC router on a long job, the shop gets noticeably warmer. I¡¯m also pulling about 70A continuous
at 240v, which is 17KW worth of heat, or the equivalent of 11 space heaters.? Needless to say, my shop heater doesn¡¯t run when I¡¯m using the router.
?
The theory of this topic is interesting.? Let¡¯s take a practical look at the situation.?
?
I have a 600 sq ft, insulated, air conditioned shop with a vaulted ceiling in Phoenix? I believe the 21 year old ac unit is rated at two tons.? I can work comfortably in my shop in the summer with the ac on and
my 5 hp clearview/festool vacs venting to the shop. ?The A/C unit doesn¡¯t run continuously once the desired temp is reached.? ?
?
I avoid working in the shop in the summer from 3-6 pm because the electric rate plan costs 4x more per kwh during that period of time.? I could make the shop too cold for comfort by running the a/c all night
but it¡¯s not necessary.? The cold a/c/ air would drop the temp of all the material in the shop which help maintain the cool temp during the day.?
?
In the winter, I heat the shop just enough to knock the chill out in the morning.? Between the heat generated from the equipment, the heat from the sun, and the heat I¡¯m producing from working makes the shop
comfortable in the winter.?
?
I have a 1400 sq ft, insulated, unheated shop in the AZ mountains where the average Jan temp ranges from 18/42F.? I could run the 36¡± wide belt sander, CF741, Planer, jointer, Bandsaw, 5 hp clearview ¡. and the
shop would never be comfortable to work in.? ?
?
?
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Show quoted text
From: [email protected] [mailto:[email protected]]
On Behalf Of TJ Cornish
Sent: Saturday, May 23, 2020 10:42 AM
To: [email protected]
Subject: Re: [FOG] Building a closet for dust collector
?
Marty, you¡¯re confusing instantaneous energy vs energy over time. If you turned your 1500w electric heater on for the same amount of time as a cut on the table saw ¨C 5 seconds or so - you would be equally disappointed in the amount of heat
generated. If you want to come over and feel the heat out of my CNC vacuum hold down table blower or the output of a large dust collector that runs for tens of minutes or several hours at a time, you will find it much easier to compare that to how we normally
use electric heaters.
?
BTW, I live in Minnesota, so I¡¯m familiar with heaters and cold temperatures.
?
To take more of a devils advocate position on this topic. If all the energy was being converted to heat then we could substitute our saws for heaters. ?
Any of you who live in cold weather know that you can work in your shop all night long when it¡¯s freezing outside and your shop would never warm to a comfortable level. ?Your body temperature may warm up from the work you¡¯re doing.
?
On May 23, 2020, at 7:36 AM, Brian Lamb <blamb11@...> wrote:
?You all are missing the point that a lot of the hp/watts is actually consumed doing the ¡°work¡±, whether it¡¯s sawing the wood, jointing, planing, sanding, lighting or even compressing air. It takes force to do most of these things (not
lighting of course), and the force of the blade cutting through the wood is a large percentage of the watts consumed. Yes, there is always a heat load, but it¡¯s not anywhere close to 100% of consumed power¡. even here in AZ where it will be 111? later this
week.
?
?
I think perhaps the issue then is the usual workload of a typical shop. Although in an it system things are, I imagine, a bit more stable in terms of draw and power use, that is not the
case for most shops not in a factory environment. We tend to turn on and off equipment and not be steadily throwing plank after plank in rapid succession thorough a saw at max force leading to an actual nameplate type draw. Whereas computer fans are typically
more blunt force objects running at max 100% of the time to account for a potentially catastrophic consequence of failing to control heat in a limited space and the consequences of those failures. And so, I may allow for a total heat release into your shop
for the sake of argument, but even then, the draw is variable and subsequently the heat release. If the OP is concerned about utilizing a motor and dealing with the heat for 100% utilization, he is probably 1) not using the right equipment as Felder doesn¡¯t
spec the duty as 100%, and 2) in the wrong forum and needs to be talking to factory owners.
But in more real world situations, we don¡¯t use 100% draw even when we are using machines most of the time, turn them off between runs, have leaks under a doors, windows to radiate out,
poor insulation to not contain heat or cold, and a myriad of other issues. Sure, running motors will increase heat but it¡¯s not a 1:1 in any of our shops, and especially not at nameplate levels.
I think you just said mostly what I did ¨C that the energy turns into heat, just not entirely in the motor itself.?
?
8KW of electricity into a room turns into 27,000 of BTU in that room, either directly or indirectly, unless that motor is driving a shaft through a wall where some of that energy is converted into heat somewhere else. That 8KW of heat may
not stay in the room due to diffusion through the room walls and ceiling, but it¡¯s put into the room, no if¡¯s, and¡¯s, or but¡¯s, just as if you had an 8KW electric resistance heater.
?
Energy is not returned to the environment on the return leg ¨C the neutral wire in a single phase 120v world, or the other hot legs in a 240v or 3-phase world. If the energy is not needed for work output or system inefficiency losses it
is not drawn in the first place; e.g. a 5HP/3KW motor has a free-running power consumption value of maybe 1KW, and that power consumption increases when the motor is asked to do work. Only when the motor is fully loaded does it draw 3KW of power. Yes there
is voltage drop on the electrical service wiring and yes there is heat generated from that lost energy, but that¡¯s a different problem in a different room. Power distribution is sized to deliver nominal voltage at the end point, factoring in losses in distribution.
?
RE designing HVAC based on electrical load ¨C yes, this is exactly how it¡¯s done. My day job is in IT, part of which includes managing a datacenter and it¡¯s power and cooling. Cooling load is absolutely sized based on power draw of computing
equipment as well as the expected environmental factors. ??
?
Small spaces like workshops ¨C small closed systems ¨C will show the temperature rise of power consumption more quickly than a larger system which has a lot more thermal sinking capability.
?
I agree it¡¯s complicated, and I¡¯m glad nothing is simple on the Felder forum, which I¡¯m new to. There are few things in life that can truly be expressed simply.? Learning stuff ¨C the reason I joined the group ¨C happens when the complexity
is welcomed.??
?
No. While you may be correct that the differences between potential energy and kinetic reach equilibrium through heat transfer, it¡¯s not so clear cut as the statement that an 8kw input to a motor yields 8kw of heat within a workshop. Within
systems there are many components, heat sinks, and losses. So for example, the spinning motor creates heat in bearings through friction, the blade creates heat through friction in the wood and drag through air, some energy is passed through entirely in the
electrical supply and leaves the system and recovers its potential in a ground, some energy is absorbed through wood fibers/saw dust and heat sinked. Heat is lost through inefficient insulation, air drafts, radiation through windows etc. Some energy is released
slowly and muddies the results like the specific heat of cast iron and sawdust. All causes, yes, 8kw input leads to 8kw of heat. But the closed system needs to be very large which simply is out of line with a real world workshop. I don¡¯t know much about sizing
hvac but I don¡¯t think this is the way to do it.
Nothing is simple on a Felder forum :) And I¡¯m waiting for my finish to dry.
All forms of energy ultimately end in heat, so yes, 8KW of energy coming in results in 8KW of heat in your shop.
?
A 3KW 5HP motor produces 3KW worth of heat ¨C electrical resistance heat in the power cord and motor windings, sliding friction heat in the bearings and air friction in parts rotating in air. Even the work output of the motor ¨C the cutting,
sanding, blowing, etc., ultimately ends up as heat ¨C if you stick your hand in a pile of just cut sawdust, it will be quite warm from the cutting tool friction and the forced deformation of the wood.
?
It is accurate to say that a 3KW motor itself doesn¡¯t itself give off 10,000 BTU of heat, but if you factor all of the losses in the system and especially the work output into whatever the motor is doing, you end up with 10,000 BTU of heat
in your room as a result of the motor running. It¡¯s counter-intuitive, but it¡¯s true.
?
I am not an expert but I am pretty sure this is not correct.
¡°?That's about 8KW of electric coming in that all turns to heat, either motor heat, or friction heat from cutting etc.¡±
Only a small portion of power being consumed is generating heat.
?Mark, I understand the thermal mass.? I often run the saw or shaper for an hour or two straight.? Sucking 110F air into my shop would definitely be a problem.? When running I have a 5HP dust collector and a 5HP saw, shaper, or sander running.
That's about 8KW of electric coming in that all turns to heat, either motor heat, or friction heat from cutting etc.? My lighting is another 2.3kw.? 1kw of electric is 3412btu so 10kw of electric in is about 34K btu.? Over 3 tons of AC.? If I ran machines
all the time and wanted to keep it cool when it's over 110F I would have had to have 10 tons of AC per the mechanical engineer.? That's without dumping exhaust outside.? Now if I were heating the machine heat would work for me and not against me.
?
|
Re: Building a closet for dust collector
It¡¯s counter-intuitive, but it is the way that it works.
?
If you feel like you¡¯re cheating the universe with your free heat, you may feel better knowing that you¡¯re paying for much more energy than it takes to break the bonds of the wood fibers. That energy is lost in however the power plant makes
the power, the distribution lines to your shop, the friction in your saw, etc. I believe coal-fired power plants are around 30% efficient in terms of extracting energy from coal and transforming it to power in your home. Your saw may be around 70% efficient
in terms of its use of the input energy in its own heating and friction vs. the energy transformed into heat. Multiply that out and your system is maybe 50% efficient. It still all ends up in heat, though.
?
Please excuse my terminology if I get it wrong,?
Well, my simple way of thinking is, that given the energy required to turn the motor,? to operate the machine ...to achieve the cutting, planing sanding etc , that you cant have 100% of the power used to generate heat, but rather a proportion
of it....
|
Re: Building a closet for dust collector
The theory of this topic is interesting.? Let¡¯s take a practical look at the situation.? ? I have a 600 sq ft, insulated, air conditioned shop with a vaulted ceiling in Phoenix? I believe the 21 year old ac unit is rated at two tons.? I can work comfortably in my shop in the summer with the ac on and my 5 hp clearview/festool vacs venting to the shop. ?The A/C unit doesn¡¯t run continuously once the desired temp is reached.? ? ? I avoid working in the shop in the summer from 3-6 pm because the electric rate plan costs 4x more per kwh during that period of time.? I could make the shop too cold for comfort by running the a/c all night but it¡¯s not necessary.? The cold a/c/ air would drop the temp of all the material in the shop which help maintain the cool temp during the day.? ? In the winter, I heat the shop just enough to knock the chill out in the morning.? Between the heat generated from the equipment, the heat from the sun, and the heat I¡¯m producing from working makes the shop comfortable in the winter.? ? I have a 1400 sq ft, insulated, unheated shop in the AZ mountains where the average Jan temp ranges from 18/42F.? I could run the 36¡± wide belt sander, CF741, Planer, jointer, Bandsaw, 5 hp clearview ¡. and the shop would never be comfortable to work in.? ? ? ?
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Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of TJ Cornish
Sent: Saturday, May 23, 2020 10:42 AM
To: [email protected]
Subject: Re: [FOG] Building a closet for dust collector? Marty, you¡¯re confusing instantaneous energy vs energy over time. If you turned your 1500w electric heater on for the same amount of time as a cut on the table saw ¨C 5 seconds or so - you would be equally disappointed in the amount of heat generated. If you want to come over and feel the heat out of my CNC vacuum hold down table blower or the output of a large dust collector that runs for tens of minutes or several hours at a time, you will find it much easier to compare that to how we normally use electric heaters. ? BTW, I live in Minnesota, so I¡¯m familiar with heaters and cold temperatures. ? To take more of a devils advocate position on this topic. If all the energy was being converted to heat then we could substitute our saws for heaters. ? Any of you who live in cold weather know that you can work in your shop all night long when it¡¯s freezing outside and your shop would never warm to a comfortable level. ?Your body temperature may warm up from the work you¡¯re doing. ? On May 23, 2020, at 7:36 AM, Brian Lamb <blamb11@...> wrote:
?You all are missing the point that a lot of the hp/watts is actually consumed doing the ¡°work¡±, whether it¡¯s sawing the wood, jointing, planing, sanding, lighting or even compressing air. It takes force to do most of these things (not lighting of course), and the force of the blade cutting through the wood is a large percentage of the watts consumed. Yes, there is always a heat load, but it¡¯s not anywhere close to 100% of consumed power¡. even here in AZ where it will be 111? later this week. ? ? I think perhaps the issue then is the usual workload of a typical shop. Although in an it system things are, I imagine, a bit more stable in terms of draw and power use, that is not the case for most shops not in a factory environment. We tend to turn on and off equipment and not be steadily throwing plank after plank in rapid succession thorough a saw at max force leading to an actual nameplate type draw. Whereas computer fans are typically more blunt force objects running at max 100% of the time to account for a potentially catastrophic consequence of failing to control heat in a limited space and the consequences of those failures. And so, I may allow for a total heat release into your shop for the sake of argument, but even then, the draw is variable and subsequently the heat release. If the OP is concerned about utilizing a motor and dealing with the heat for 100% utilization, he is probably 1) not using the right equipment as Felder doesn¡¯t spec the duty as 100%, and 2) in the wrong forum and needs to be talking to factory owners. But in more real world situations, we don¡¯t use 100% draw even when we are using machines most of the time, turn them off between runs, have leaks under a doors, windows to radiate out, poor insulation to not contain heat or cold, and a myriad of other issues. Sure, running motors will increase heat but it¡¯s not a 1:1 in any of our shops, and especially not at nameplate levels.
I think you just said mostly what I did ¨C that the energy turns into heat, just not entirely in the motor itself.? ? 8KW of electricity into a room turns into 27,000 of BTU in that room, either directly or indirectly, unless that motor is driving a shaft through a wall where some of that energy is converted into heat somewhere else. That 8KW of heat may not stay in the room due to diffusion through the room walls and ceiling, but it¡¯s put into the room, no if¡¯s, and¡¯s, or but¡¯s, just as if you had an 8KW electric resistance heater. ? Energy is not returned to the environment on the return leg ¨C the neutral wire in a single phase 120v world, or the other hot legs in a 240v or 3-phase world. If the energy is not needed for work output or system inefficiency losses it is not drawn in the first place; e.g. a 5HP/3KW motor has a free-running power consumption value of maybe 1KW, and that power consumption increases when the motor is asked to do work. Only when the motor is fully loaded does it draw 3KW of power. Yes there is voltage drop on the electrical service wiring and yes there is heat generated from that lost energy, but that¡¯s a different problem in a different room. Power distribution is sized to deliver nominal voltage at the end point, factoring in losses in distribution. ? RE designing HVAC based on electrical load ¨C yes, this is exactly how it¡¯s done. My day job is in IT, part of which includes managing a datacenter and it¡¯s power and cooling. Cooling load is absolutely sized based on power draw of computing equipment as well as the expected environmental factors. ?? ? Small spaces like workshops ¨C small closed systems ¨C will show the temperature rise of power consumption more quickly than a larger system which has a lot more thermal sinking capability. ? I agree it¡¯s complicated, and I¡¯m glad nothing is simple on the Felder forum, which I¡¯m new to. There are few things in life that can truly be expressed simply.? Learning stuff ¨C the reason I joined the group ¨C happens when the complexity is welcomed.?? ? No. While you may be correct that the differences between potential energy and kinetic reach equilibrium through heat transfer, it¡¯s not so clear cut as the statement that an 8kw input to a motor yields 8kw of heat within a workshop. Within systems there are many components, heat sinks, and losses. So for example, the spinning motor creates heat in bearings through friction, the blade creates heat through friction in the wood and drag through air, some energy is passed through entirely in the electrical supply and leaves the system and recovers its potential in a ground, some energy is absorbed through wood fibers/saw dust and heat sinked. Heat is lost through inefficient insulation, air drafts, radiation through windows etc. Some energy is released slowly and muddies the results like the specific heat of cast iron and sawdust. All causes, yes, 8kw input leads to 8kw of heat. But the closed system needs to be very large which simply is out of line with a real world workshop. I don¡¯t know much about sizing hvac but I don¡¯t think this is the way to do it. Nothing is simple on a Felder forum :) And I¡¯m waiting for my finish to dry.
All forms of energy ultimately end in heat, so yes, 8KW of energy coming in results in 8KW of heat in your shop. ? A 3KW 5HP motor produces 3KW worth of heat ¨C electrical resistance heat in the power cord and motor windings, sliding friction heat in the bearings and air friction in parts rotating in air. Even the work output of the motor ¨C the cutting, sanding, blowing, etc., ultimately ends up as heat ¨C if you stick your hand in a pile of just cut sawdust, it will be quite warm from the cutting tool friction and the forced deformation of the wood. ? It is accurate to say that a 3KW motor itself doesn¡¯t itself give off 10,000 BTU of heat, but if you factor all of the losses in the system and especially the work output into whatever the motor is doing, you end up with 10,000 BTU of heat in your room as a result of the motor running. It¡¯s counter-intuitive, but it¡¯s true. ? I am not an expert but I am pretty sure this is not correct. ¡°?That's about 8KW of electric coming in that all turns to heat, either motor heat, or friction heat from cutting etc.¡± Only a small portion of power being consumed is generating heat. ?Mark, I understand the thermal mass.? I often run the saw or shaper for an hour or two straight.? Sucking 110F air into my shop would definitely be a problem.? When running I have a 5HP dust collector and a 5HP saw, shaper, or sander running. That's about 8KW of electric coming in that all turns to heat, either motor heat, or friction heat from cutting etc.? My lighting is another 2.3kw.? 1kw of electric is 3412btu so 10kw of electric in is about 34K btu.? Over 3 tons of AC.? If I ran machines all the time and wanted to keep it cool when it's over 110F I would have had to have 10 tons of AC per the mechanical engineer.? That's without dumping exhaust outside.? Now if I were heating the machine heat would work for me and not against me.
?
|
Re: Building a closet for dust collector
Please excuse my terminology if I get it wrong,? Well, my simple way of thinking is, that given the energy required to turn the motor,? to operate the machine ...to achieve the cutting, planing sanding etc , that you cant have 100% of the power used to generate heat, but rather a proportion of it....
Stephen
|
Re: Building a closet for dust collector
Yes ¨C exactly. It¡¯s rare that there¡¯s a free lunch in life, but if you want the heat your tool makes at the same time that you want the function of whatever your tool does, then this is one of those rare situations where you get 2 for the
price of 1.
?
TJ,
So you are saying that in fact an electric motor is MORE efficient than an electric heater, because you get the same heat output AS WELL as the benefit of the motor having performed work...well this is news to me...
?
toggle quoted message
Show quoted text
On Sat, 23 May 2020, 18:38 TJ Cornish, < tj@...> wrote:
If all you are considering is the heat output of the machine and not the financial costs of wear and tear on motors, belts, bearings, etc., then yes, an electric power tool is just
as efficient at making heat as a heater is, with the benefit that it can multitask and perform useful work while it and the work done makes the heat.
?
There is confusion here between ¡°efficiency¡± ¨C how much energy input is required to perform a task, and energy conservation ¨C in other words, where does all the electrical energy
go. Efficiency is great ¨C yes, let¡¯s find ways to do useful things with less energy input, whether that is punching metal instead of milling, using thin kerf saw blades instead of rebate heads to remove large chunks of material, etc. (I¡¯m not advocating for
any particular procedure, obviously there are many reasons why you may do an operation in a way that requires more electrical power but gives advantages in safety, speed, finish quality, etc.). My one and only point in all of this typing is simply:
?
Whatever energy you pull from the wall ¨C whether continuous or intermittent usage, use it fast, use it slow, ALL of that energy that is not stored in another form ¨C chemically in
a battery, mechanically in a flywheel or by lifting something ¨C ALL of that energy will heat your space.
?
Back to efficiency ¨C if you are using your power tools anyway, the heat they make is free as it is a waste product of the purpose of the tool. In that sense, your power tools are
absolutely the cheapest heat you can get (assuming you need to run them to do something). If your heat demands exceed your power tool usage patterns, then electric heat of any form ¨C running your tools more often or electric heat ¨C is probably not the most
efficient or cost-effective way to heat your shop.? Right now natural gas is by far the cheapest source of heat energy.
?
TJ and others,
My simple mind may have missed the point of these theories, but are you telling me that it is as efficient(financially) to heat my workshop with a running machine as it is with
an electric heater, as far as units on my electric meter is concerned?
|
Re: Building a closet for dust collector
TJ, So you are saying that in fact an electric motor is MORE efficient than an electric heater, because you get the same heat output AS WELL as the benefit of the motor having performed work...well this is news to me...
Stephen?
On Sat, 23 May 2020, 18:38 TJ Cornish, < tj@...> wrote:
If all you are considering is the heat output of the machine and not the financial costs of wear and tear on motors, belts, bearings, etc., then yes, an electric power tool is just as efficient at making heat as a heater is, with the benefit
that it can multitask and perform useful work while it and the work done makes the heat.
?
There is confusion here between ¡°efficiency¡± ¨C how much energy input is required to perform a task, and energy conservation ¨C in other words, where does all the electrical energy go. Efficiency is great ¨C yes, let¡¯s find ways to do useful
things with less energy input, whether that is punching metal instead of milling, using thin kerf saw blades instead of rebate heads to remove large chunks of material, etc. (I¡¯m not advocating for any particular procedure, obviously there are many reasons
why you may do an operation in a way that requires more electrical power but gives advantages in safety, speed, finish quality, etc.). My one and only point in all of this typing is simply:
?
Whatever energy you pull from the wall ¨C whether continuous or intermittent usage, use it fast, use it slow, ALL of that energy that is not stored in another form ¨C chemically in a battery, mechanically in a flywheel or by lifting something
¨C ALL of that energy will heat your space.
?
Back to efficiency ¨C if you are using your power tools anyway, the heat they make is free as it is a waste product of the purpose of the tool. In that sense, your power tools are absolutely the cheapest heat you can get (assuming you need
to run them to do something). If your heat demands exceed your power tool usage patterns, then electric heat of any form ¨C running your tools more often or electric heat ¨C is probably not the most efficient or cost-effective way to heat your shop.? Right now
natural gas is by far the cheapest source of heat energy.
?
TJ and others,
My simple mind may have missed the point of these theories, but are you telling me that it is as efficient(financially) to heat my workshop with a running machine as it is with an electric heater, as far as units on my electric meter is
concerned?
|
Re: Building a closet for dust collector
Marty, you¡¯re confusing instantaneous energy vs energy over time. If you turned your 1500w electric heater on for the same amount of time as a cut on the table saw ¨C 5 seconds or so - you would be equally disappointed in the amount of heat
generated. If you want to come over and feel the heat out of my CNC vacuum hold down table blower or the output of a large dust collector that runs for tens of minutes or several hours at a time, you will find it much easier to compare that to how we normally
use electric heaters.
?
BTW, I live in Minnesota, so I¡¯m familiar with heaters and cold temperatures.
?
To take more of a devils advocate position on this topic. If all the energy was being converted to heat then we could substitute our saws for heaters. ?
Any of you who live in cold weather know that you can work in your shop all night long when it¡¯s freezing outside and your shop would never warm to a comfortable level. ?Your body temperature may warm up from the work you¡¯re doing.
toggle quoted message
Show quoted text
On May 23, 2020, at 7:36 AM, Brian Lamb <blamb11@...> wrote:
?You all are missing the point that a lot of the hp/watts is actually consumed doing the ¡°work¡±, whether it¡¯s sawing the wood, jointing, planing, sanding, lighting or even compressing air. It takes force to do most of these things (not
lighting of course), and the force of the blade cutting through the wood is a large percentage of the watts consumed. Yes, there is always a heat load, but it¡¯s not anywhere close to 100% of consumed power¡. even here in AZ where it will be 111? later this
week.
?
?
I think perhaps the issue then is the usual workload of a typical shop. Although in an it system things are, I imagine, a bit more stable in terms of draw and power use, that is not the
case for most shops not in a factory environment. We tend to turn on and off equipment and not be steadily throwing plank after plank in rapid succession thorough a saw at max force leading to an actual nameplate type draw. Whereas computer fans are typically
more blunt force objects running at max 100% of the time to account for a potentially catastrophic consequence of failing to control heat in a limited space and the consequences of those failures. And so, I may allow for a total heat release into your shop
for the sake of argument, but even then, the draw is variable and subsequently the heat release. If the OP is concerned about utilizing a motor and dealing with the heat for 100% utilization, he is probably 1) not using the right equipment as Felder doesn¡¯t
spec the duty as 100%, and 2) in the wrong forum and needs to be talking to factory owners.
But in more real world situations, we don¡¯t use 100% draw even when we are using machines most of the time, turn them off between runs, have leaks under a doors, windows to radiate out,
poor insulation to not contain heat or cold, and a myriad of other issues. Sure, running motors will increase heat but it¡¯s not a 1:1 in any of our shops, and especially not at nameplate levels.
I think you just said mostly what I did ¨C that the energy turns into heat, just not entirely in the motor itself.?
?
8KW of electricity into a room turns into 27,000 of BTU in that room, either directly or indirectly, unless that motor is driving a shaft through a wall where some of that energy is converted into heat somewhere else. That 8KW of heat may
not stay in the room due to diffusion through the room walls and ceiling, but it¡¯s put into the room, no if¡¯s, and¡¯s, or but¡¯s, just as if you had an 8KW electric resistance heater.
?
Energy is not returned to the environment on the return leg ¨C the neutral wire in a single phase 120v world, or the other hot legs in a 240v or 3-phase world. If the energy is not needed for work output or system inefficiency losses it
is not drawn in the first place; e.g. a 5HP/3KW motor has a free-running power consumption value of maybe 1KW, and that power consumption increases when the motor is asked to do work. Only when the motor is fully loaded does it draw 3KW of power. Yes there
is voltage drop on the electrical service wiring and yes there is heat generated from that lost energy, but that¡¯s a different problem in a different room. Power distribution is sized to deliver nominal voltage at the end point, factoring in losses in distribution.
?
RE designing HVAC based on electrical load ¨C yes, this is exactly how it¡¯s done. My day job is in IT, part of which includes managing a datacenter and it¡¯s power and cooling. Cooling load is absolutely sized based on power draw of computing
equipment as well as the expected environmental factors. ??
?
Small spaces like workshops ¨C small closed systems ¨C will show the temperature rise of power consumption more quickly than a larger system which has a lot more thermal sinking capability.
?
I agree it¡¯s complicated, and I¡¯m glad nothing is simple on the Felder forum, which I¡¯m new to. There are few things in life that can truly be expressed simply.? Learning stuff ¨C the reason I joined the group ¨C happens when the complexity
is welcomed.??
?
No. While you may be correct that the differences between potential energy and kinetic reach equilibrium through heat transfer, it¡¯s not so clear cut as the statement that an 8kw input to a motor yields 8kw of heat within a workshop. Within
systems there are many components, heat sinks, and losses. So for example, the spinning motor creates heat in bearings through friction, the blade creates heat through friction in the wood and drag through air, some energy is passed through entirely in the
electrical supply and leaves the system and recovers its potential in a ground, some energy is absorbed through wood fibers/saw dust and heat sinked. Heat is lost through inefficient insulation, air drafts, radiation through windows etc. Some energy is released
slowly and muddies the results like the specific heat of cast iron and sawdust. All causes, yes, 8kw input leads to 8kw of heat. But the closed system needs to be very large which simply is out of line with a real world workshop. I don¡¯t know much about sizing
hvac but I don¡¯t think this is the way to do it.
Nothing is simple on a Felder forum :) And I¡¯m waiting for my finish to dry.
All forms of energy ultimately end in heat, so yes, 8KW of energy coming in results in 8KW of heat in your shop.
?
A 3KW 5HP motor produces 3KW worth of heat ¨C electrical resistance heat in the power cord and motor windings, sliding friction heat in the bearings and air friction in parts rotating in air. Even the work output of the motor ¨C the cutting,
sanding, blowing, etc., ultimately ends up as heat ¨C if you stick your hand in a pile of just cut sawdust, it will be quite warm from the cutting tool friction and the forced deformation of the wood.
?
It is accurate to say that a 3KW motor itself doesn¡¯t itself give off 10,000 BTU of heat, but if you factor all of the losses in the system and especially the work output into whatever the motor is doing, you end up with 10,000 BTU of heat
in your room as a result of the motor running. It¡¯s counter-intuitive, but it¡¯s true.
?
I am not an expert but I am pretty sure this is not correct.
¡°?That's about 8KW of electric coming in that all turns to heat, either motor heat, or friction heat from cutting etc.¡±
Only a small portion of power being consumed is generating heat.
?Mark, I understand the thermal mass.? I often run the saw or shaper for an hour or two straight.? Sucking 110F air into my shop would definitely be a problem.? When running I have a 5HP dust collector and a 5HP saw, shaper, or sander running.
That's about 8KW of electric coming in that all turns to heat, either motor heat, or friction heat from cutting etc.? My lighting is another 2.3kw.? 1kw of electric is 3412btu so 10kw of electric in is about 34K btu.? Over 3 tons of AC.? If I ran machines
all the time and wanted to keep it cool when it's over 110F I would have had to have 10 tons of AC per the mechanical engineer.? That's without dumping exhaust outside.? Now if I were heating the machine heat would work for me and not against me.
?
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Re: Building a closet for dust collector
If all you are considering is the heat output of the machine and not the financial costs of wear and tear on motors, belts, bearings, etc., then yes, an electric power tool is just as efficient at making heat as a heater is, with the benefit
that it can multitask and perform useful work while it and the work done makes the heat.
?
There is confusion here between ¡°efficiency¡± ¨C how much energy input is required to perform a task, and energy conservation ¨C in other words, where does all the electrical energy go. Efficiency is great ¨C yes, let¡¯s find ways to do useful
things with less energy input, whether that is punching metal instead of milling, using thin kerf saw blades instead of rebate heads to remove large chunks of material, etc. (I¡¯m not advocating for any particular procedure, obviously there are many reasons
why you may do an operation in a way that requires more electrical power but gives advantages in safety, speed, finish quality, etc.). My one and only point in all of this typing is simply:
?
Whatever energy you pull from the wall ¨C whether continuous or intermittent usage, use it fast, use it slow, ALL of that energy that is not stored in another form ¨C chemically in a battery, mechanically in a flywheel or by lifting something
¨C ALL of that energy will heat your space.
?
Back to efficiency ¨C if you are using your power tools anyway, the heat they make is free as it is a waste product of the purpose of the tool. In that sense, your power tools are absolutely the cheapest heat you can get (assuming you need
to run them to do something). If your heat demands exceed your power tool usage patterns, then electric heat of any form ¨C running your tools more often or electric heat ¨C is probably not the most efficient or cost-effective way to heat your shop.? Right now
natural gas is by far the cheapest source of heat energy.
?
TJ and others,
My simple mind may have missed the point of these theories, but are you telling me that it is as efficient(financially) to heat my workshop with a running machine as it is with an electric heater, as far as units on my electric meter is
concerned?
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Re: Building a closet for dust collector
I agree with Brian. ??
To take more of a devils advocate position on this topic. If all the energy was being converted to heat then we could substitute our saws for heaters. ?
Any of you who live in cold weather know that you can work in your shop all night long when it¡¯s freezing outside and your shop would never warm to a comfortable level. ?Your body temperature may warm up from the work you¡¯re doing.
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On May 23, 2020, at 7:36 AM, Brian Lamb <blamb11@...> wrote:
? You all are missing the point that a lot of the hp/watts is actually consumed doing the ¡°work¡±, whether it¡¯s sawing the wood, jointing, planing, sanding, lighting or even compressing air. It takes force to do most of these things (not lighting of course), and the force of the blade cutting through the wood is a large percentage of the watts consumed. Yes, there is always a heat load, but it¡¯s not anywhere close to 100% of consumed power¡. even here in AZ where it will be 111? later this week.
I think perhaps the issue then is the usual workload of a typical shop. Although in an it system things are, I imagine, a bit more stable in terms of draw and power use, that is not the case for most shops not in a factory environment. We tend to turn on and off equipment and not be steadily throwing plank after plank in rapid succession thorough a saw at max force leading to an actual nameplate type draw. Whereas computer fans are typically more blunt force objects running at max 100% of the time to account for a potentially catastrophic consequence of failing to control heat in a limited space and the consequences of those failures. And so, I may allow for a total heat release into your shop for the sake of argument, but even then, the draw is variable and subsequently the heat release. If the OP is concerned about utilizing a motor and dealing with the heat for 100% utilization, he is probably 1) not using the right equipment as Felder doesn¡¯t spec the duty as 100%, and 2) in the wrong forum and needs to be talking to factory owners.
But in more real world situations, we don¡¯t use 100% draw even when we are using machines most of the time, turn them off between runs, have leaks under a doors, windows to radiate out, poor insulation to not contain heat or cold, and a myriad of other issues. Sure, running motors will increase heat but it¡¯s not a 1:1 in any of our shops, and especially not at nameplate levels.
Get?
I think you just said mostly what I did ¨C that the energy turns into heat, just not entirely in the motor itself.? ? 8KW of electricity into a room turns into 27,000 of BTU in that room, either directly or indirectly, unless that motor is driving a shaft through a wall where some of that energy is converted into heat somewhere else. That 8KW of heat may not stay in the room due to diffusion through the room walls and ceiling, but it¡¯s put into the room, no if¡¯s, and¡¯s, or but¡¯s, just as if you had an 8KW electric resistance heater. ? Energy is not returned to the environment on the return leg ¨C the neutral wire in a single phase 120v world, or the other hot legs in a 240v or 3-phase world. If the energy is not needed for work output or system inefficiency losses it is not drawn in the first place; e.g. a 5HP/3KW motor has a free-running power consumption value of maybe 1KW, and that power consumption increases when the motor is asked to do work. Only when the motor is fully loaded does it draw 3KW of power. Yes there is voltage drop on the electrical service wiring and yes there is heat generated from that lost energy, but that¡¯s a different problem in a different room. Power distribution is sized to deliver nominal voltage at the end point, factoring in losses in distribution. ? RE designing HVAC based on electrical load ¨C yes, this is exactly how it¡¯s done. My day job is in IT, part of which includes managing a datacenter and it¡¯s power and cooling. Cooling load is absolutely sized based on power draw of computing equipment as well as the expected environmental factors. ?? ? Small spaces like workshops ¨C small closed systems ¨C will show the temperature rise of power consumption more quickly than a larger system which has a lot more thermal sinking capability. ? I agree it¡¯s complicated, and I¡¯m glad nothing is simple on the Felder forum, which I¡¯m new to. There are few things in life that can truly be expressed simply.? Learning stuff ¨C the reason I joined the group ¨C happens when the complexity is welcomed.?? ? No. While you may be correct that the differences between potential energy and kinetic reach equilibrium through heat transfer, it¡¯s not so clear cut as the statement that an 8kw input to a motor yields 8kw of heat within a workshop. Within systems there are many components, heat sinks, and losses. So for example, the spinning motor creates heat in bearings through friction, the blade creates heat through friction in the wood and drag through air, some energy is passed through entirely in the electrical supply and leaves the system and recovers its potential in a ground, some energy is absorbed through wood fibers/saw dust and heat sinked. Heat is lost through inefficient insulation, air drafts, radiation through windows etc. Some energy is released slowly and muddies the results like the specific heat of cast iron and sawdust. All causes, yes, 8kw input leads to 8kw of heat. But the closed system needs to be very large which simply is out of line with a real world workshop. I don¡¯t know much about sizing hvac but I don¡¯t think this is the way to do it. Nothing is simple on a Felder forum :) And I¡¯m waiting for my finish to dry.
All forms of energy ultimately end in heat, so yes, 8KW of energy coming in results in 8KW of heat in your shop. ? A 3KW 5HP motor produces 3KW worth of heat ¨C electrical resistance heat in the power cord and motor windings, sliding friction heat in the bearings and air friction in parts rotating in air. Even the work output of the motor ¨C the cutting, sanding, blowing, etc., ultimately ends up as heat ¨C if you stick your hand in a pile of just cut sawdust, it will be quite warm from the cutting tool friction and the forced deformation of the wood. ? It is accurate to say that a 3KW motor itself doesn¡¯t itself give off 10,000 BTU of heat, but if you factor all of the losses in the system and especially the work output into whatever the motor is doing, you end up with 10,000 BTU of heat in your room as a result of the motor running. It¡¯s counter-intuitive, but it¡¯s true. ? I am not an expert but I am pretty sure this is not correct. ¡°?That's about 8KW of electric coming in that all turns to heat, either motor heat, or friction heat from cutting etc.¡± Only a small portion of power being consumed is generating heat. ?Mark, I understand the thermal mass.? I often run the saw or shaper for an hour or two straight.? Sucking 110F air into my shop would definitely be a problem.? When running I have a 5HP dust collector and a 5HP saw, shaper, or sander running. That's about 8KW of electric coming in that all turns to heat, either motor heat, or friction heat from cutting etc.? My lighting is another 2.3kw.? 1kw of electric is 3412btu so 10kw of electric in is about 34K btu.? Over 3 tons of AC.? If I ran machines all the time and wanted to keep it cool when it's over 110F I would have had to have 10 tons of AC per the mechanical engineer.? That's without dumping exhaust outside.? Now if I were heating the machine heat would work for me and not against me.
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I was going to suggest to rerun the board after planning without changing table height. It should eliminate resistance from cutter or concern of cutting height.
Imran
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On May 23, 2020, at 1:27 PM, Alex Bowlds <aabj@...> wrote: ? I agree with Brian, start with cleaning and waxing the table. ?That should improve your problem, but may not completely correct it. ?Then make sure your knives/cutters are sharp. ?They can also contribute to the problem. ?Do these things before you consider adjusting or replacing the pressure rollers. ?It wouldn¡¯t hurt to try to clean the feed rollers too.
Good luck,
Alex On May 23, 2020, at 8:14 AM, Brian Lamb <blamb11@...> wrote:
? Try waxing the table surface first.
On May 22, 2020, at 6:59 PM, johnjgram via < johnjgram@...> wrote:
When are you use the thickness planer the rowers seem to be turning but when I put the word in there I can Them it doesn¡¯t feed the wood I have to push like hell and then pull it out penny Any thoughts
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I agree with Brian, start with cleaning and waxing the table. ?That should improve your problem, but may not completely correct it. ?Then make sure your knives/cutters are sharp. ?They can also contribute to the problem. ?Do these things before you consider adjusting or replacing the pressure rollers. ?It wouldn¡¯t hurt to try to clean the feed rollers too.
Good luck,
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On May 23, 2020, at 8:14 AM, Brian Lamb <blamb11@...> wrote:
? Try waxing the table surface first.
On May 22, 2020, at 6:59 PM, johnjgram via < johnjgram@...> wrote:
When are you use the thickness planer the rowers seem to be turning but when I put the word in there I can Them it doesn¡¯t feed the wood I have to push like hell and then pull it out penny Any thoughts
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Re: Building a closet for dust collector
On Sat, May 23, 2020 at 09:22 AM, Brian Lamb wrote:
In AZ where we have massive heat loads in the summer, exhausting air outside is a foolish endeavor
Maybe, but foolish is relative.? My point is that it might be worth quantifying, since everything is a tradeoff. For exampling, using my previous estimate of costing $2.50/hr to make up for lost DC exhaust cooling, that might be a very "foolish" loss rate for 24x7 operation like a house ($18k/year), but less foolish for a DC running an hour per day ($900/yr) One could say it's foolish to have a 2400 sq ft shop.? Or maybe 2400 ft the sweet spot, and 5,000 ft is foolish.? Or foolish to set themostat at 68 instead of 75.? ?Or foolish to spend $200k on hobby equipment.?? Some people think it's foolish that humans inhabited Arizona.?? I'm just saying, without some attempt to quantify and put it into one's personal context, just declaring it infeasible or foolish seems not very well grounded.
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Re: Building a closet for dust collector
TJ and others, My simple mind may have missed the point of these theories, but are you telling me that it is as efficient(financially) to heat my workshop with a running machine as it is with an electric heater, as far as units on my electric meter is concerned?
Regards? Stephen?
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Re: Building a closet for dust collector
Brian, an LED light bulb might be more ¡°efficient¡± in the sense that you may get the same number of lumens as a 100W tungsten bulb with only a 15w LED bulb, but that¡¯s a different problem. The 15 watts of electrical power the LED bulb consumes
still all end up as heat.
?
Back to your punching vs. milling example ¨C if you think about the work done ¨C in a punch all you are only deforming the perimeter of what you are punching. When you mill the same area you¡¯re doing a lot more ¡°work¡± ¨C deforming almost all
of the area of the milled section to get the same result.? Punching is a more efficient process than milling for sure, both in energy required and operational time. The amount of energy required to spool up the flywheel in your punch will be less than the
milling operation, but all of the energy used no matter the process turns into heat in your shop.
?
?
Agreed, the horse has heat, but in the case of lighting, the lumens is the ¡°work¡±, we get the same amount of lumens from 15 watts (LED) as we do 100W of incandescent. Put the 100W vs. the 15W in your box and the temperature rise will not
be the same.
All this is moot anyway, we are talking about HVAC loads and what is practical. In AZ where we have massive heat loads in the summer, exhausting air outside is a foolish endeavor and doing the best to deaden the acoustics is worthwhile.
?
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On May 23, 2020, at 9:10 AM, mark thomas <murkyd@...> wrote:
?
Brian, put your hand on a horse that's just standing around doing nothing, and then put your hand on a horse that's been working.? ?You'll feel the heat.
Part of what's confusing is the timeframe of heat moving, and again the system boundary.? In the light bulb case, some of the energy is quickly and locally converted directly to heat, and that's what you think of as the "waste" or "loss".? ?
An incandescent may convert 90% to heat immediately and the remaining 10% later.? ?An LED may convert 10% to heat immediately and the remaining 90% later.? ?But the energy moved into photons is just delayed and distant heat.? The photons stream across the room
and hit a surface, and some of those photons heat up the surface, and some bounce off and then land somewhere else, and heat up that surface, etc...
This is actually very easy to demonstrate.? Make?an opaque box (closed system) and put a 100w incandescent bulb in it and measure temperature rise over time X, then do the same with a 100W LED bulb.? The results will be identical.? ? ?
?
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Re: Building a closet for dust collector
On Sat, May 23, 2020 at 09:22 AM, Brian Lamb wrote:
Agreed, the horse has heat, but in the case of lighting, the lumens is the ¡°work¡±, we get the same amount of lumens from 15 watts (LED) as we do 100W of incandescent. Put the 100W vs. the 15W in your box and the temperature rise will not be the same.
?
Lumens is "work" only as metaphor, and by the same token, heating is also "work".? ?The "work" a heat lamp does is heating for example. Ask yourself this: where did the light "work" go after the light is switched off?? You can't open the box and find the lumens resting on the bottom. The lumens are just an intermediate place where the energy resides, in between the electricity in and the resultant heat. At any instantaneous moment, the 100W LED will be doing more "light work" (brighter inside) and less immediate "heating work" than the incandescent, which will be doing less "light work" (dimmer) and more immediate "heating work".? ? But then 100% of the lumens are absorbed into the walls of the box and the air in the box. Another way of looking at it that a 100W incandescent and 100 LED inside a box (where you can't use the "light work)" are identical heaters.
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Re: Building a closet for dust collector
On Sat, May 23, 2020 at 09:09 AM, Joe Jensen wrote:
That assumes I have a large enough heat pump for the additional load.? I do not.
?
As I noted, may not make sense for you.? Obviously I'm not assessing your specific application, just noting that assessment is more complex than cfm x outside air temp.? For example, there is no engineering requirement to remove heat at the same rate as it's added.? If you add 50kw of heat in an hour and take 3 hour to remove it, you'll get some temp fluctuation over that time meantime, but whether that's a problem is personal and subjective, not an engineering issue. Overall, my point here was that exhausting outside obviously has possible comfort impact and some financial impact, and while I've seen lots of people over the years simply assert that exhausting outside is infeasible, I've never seen anyone quantify it.? I suspect in most cases, the impact is a lot smaller than people assume.
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Re: Building a closet for dust collector
Agreed, the horse has heat, but in the case of lighting, the lumens is the ¡°work¡±, we get the same amount of lumens from 15 watts (LED) as we do 100W of incandescent. Put the 100W vs. the 15W in your box and the temperature rise will not be the same.
All this is moot anyway, we are talking about HVAC loads and what is practical. In AZ where we have massive heat loads in the summer, exhausting air outside is a foolish endeavor and doing the best to deaden the acoustics is worthwhile.
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On May 23, 2020, at 9:10 AM, mark thomas < murkyd@...> wrote:
Brian, put your hand on a horse that's just standing around doing nothing, and then put your hand on a horse that's been working.? ?You'll feel the heat.
Part of what's confusing is the timeframe of heat moving, and again the system boundary.? In the light bulb case, some of the energy is quickly and locally converted directly to heat, and that's what you think of as the "waste" or "loss".? ?
An incandescent may convert 90% to heat immediately and the remaining 10% later.? ?An LED may convert 10% to heat immediately and the remaining 90% later.? ?But the energy moved into photons is just delayed and distant heat.? The photons stream across the room and hit a surface, and some of those photons heat up the surface, and some bounce off and then land somewhere else, and heat up that surface, etc...
This is actually very easy to demonstrate.? Make?an opaque box (closed system) and put a 100w incandescent bulb in it and measure temperature rise over time X, then do the same with a 100W LED bulb.? The results will be identical.? ? ?
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Re: Building a closet for dust collector
I am an electrical engineer who is 12 credits short of a second degree in mechanical engineering.? TJ is correct in that any energy coming into the room either turns into potential energy or it is released in the room as heat.? Yes, the motors are not running full load all the time.? I run my sander for example at about 2/3rds full load amps.? My dust collector runs 2 amps below FLA all the time as this is how the VFD is programmed.??
Rough math, HVAC efficiency is such that removing 1kw of energy from the room takes 3kw of HVAC energy.??
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marty shultz
imran
Joe Jensen