Posted Sat Dec 20, 2003, 6:58pm Subject: Tea - power usage (approximate)
dan_kehn Said:
This reminds me of another offline debate: Will you consume more electricity bringing an E61 type machine up to full temperature more than once in a day than you otherwise would by leaving it on 24/7? I'm a little skeptical, but it could be true.
This morning, I got up earlier than the timer was set for, remembered this question and did a bit of timing on my Isomac Tea as it warmed up (I got to the kitchen just as it started to register pressure on the gauge). The Tea has a 1400w heating element in a 1.4 liter boiler, YMMV.
It took about 10 minutes (by the readout on the programmable timer) of steady heat before the machine started cycling. The first Off-on cycle took about 30 seconds (25 off/5 on). After an hour, (after morning coffee and tea, and a 10 minutes or so to stabilize) the cycle was about 5 sec on, with nearly a minute between cycles (54 off/5 on). Assuming a linear increase in 'off time' to equilibrium slightly overstates the power needed for a 'cold start', which is ok for this rough comparison.
ljguitar Senior Member Joined: 28 Jan 2003 Posts: 2,450 Location: Cheyenne Expertise: I live coffee
Espresso: Expobar Pulsar Grinder: Mazzer Super Jolly, Solis Drip: Bunn Roaster: iRoast2
Posted Sat Dec 20, 2003, 7:30pm Subject: Re: Tea - power usage (approximate)
Hi Ted... If the only consideration were $$ and kilowatts, then you might be right.
I own a recording studio, and though it would perhaps use a bit less electricity to turn it off during breaks, lunches etc., we let the equipment run. Every time you heat it and cool it down and reheat it, the circuits start reacting to the repeated rapid stresses on them. It is accepted in the industry that turning equipment on and off repeatedly wears components out and breaks things more quickly than just allowing it to run.
Switches wear out and break, and subjecting the circuits to the shock of on and off cycling injure more things than allowing them to run.
Tube equipment takes 45 minutes to an hour to heat and stabalize (all my mic preamps are tube type). Once eqiuipment goes on in the morning, it stays on till we are done with sessions for the day.
Same with all the computers...once they are on, they are only allowed to sleep during idle periods rather than completely shutting them down and rebooting them. CD burners on the other hand are warmed for 45 minutes before we burn CDs and the shut down, because we don't burn till then end of the day's/week's sessions.
I would equate sleeping the computer with the espresso machine idling and cycling. I know that there is some heated discussion concerning commercial machines as to the extra stress on boilers that is associated with frequent cooling, and what the possible ramifications of long term colling and reheating does to them.
Sometimes my espresso equipment is on the timer which comes on at 5:30am and goes off at 10:30pm, and at other times if we are using it pretty heavily, it just stays on 24/7. While we were on a 3 week vacation, we allowed it to run and had a friend who was watching our parrot draw off 8 oz of water a day and refill the reservoir so the water would not get bacterial or start growing algae.
The considerations for us are:
The espresso machine is hot when we need it (want it).
It retains stability because it is thoroughly heated.
We guess it is easier on equipment to run continuously through the day than to heat, cool, reheat, cool, reheat, cool.
This is a mixture of fact and guessing based on experience. Obviously if you have a thermal block espresso machine, or a LaPavoni lever, you would not heat it till you needed it. These machines have short heat up times.
Probably more relevant is where and when you intend to spend dollars. If servicing the machine more frequently balances the green aspects of saving energy, then a person would heat and cool the machines for specific use. If convenience and stability outweigh energy concerns, then letting it run would be in order.
Posted Sat Dec 20, 2003, 8:27pm Subject: Re: Tea - power usage (approximate)
marrone Said:
Won't take long for the the programmable timer to pay off.
You've inspired me to refine my measurements! I had roughly estimated a six hour payback and yours is less than four hours. I think yours is more accurate. I'll try your back-of-the-hand estimation methodology tomorrow morning.
ljguitar Said:
Every time you heat it and cool it down and reheat it, the circuits start reacting to the repeated rapid stresses on them. It is accepted in the industry that turning equipment on and off repeatedly wears components out and breaks things more quickly than just allowing it to run.
I know nothing about sound equipment, however what you say about tube equipment makes intuitive sense. As for ICs, the "stress" argument for 24/7 operation in the computer industry has been repeated so often that it has passed into urban legend. Apparently this question comes up a lot, as I had no problem finding opinions (search)! I found a few good points I hadn't considered in How Stuff Works' answer to the question Is it better to turn my computer off when I am not using it or leave it on all the time? I was kind of thinking "yeah, yeah, yeah" until I read the last point:
Most vendors will sell you a three-year full-replacement warranty for about $150. If you are worried about it, spend some of the money you are saving by turning your machine off and buy a service contract. Over three years, you come out way ahead!
The author is right, a three-year extended warranty isn't all that expensive (and sometimes included, as with high-end laptops), so the mean time between failure rates (MTBF) must be pretty darn high. BTW, the article Put your PC to bed at night gave some practical hints on saving energy without suffering a long startup (one that I forgot, duh!). Whether failure rates of computers extend to espresso machine components is beyond me. At least now I know the electronic circuitry won't care. ;-)
For those who have recently joined the board, below is a sampling of past discussions of the costs and benefits of 24/7 operation:
Posted Sat Dec 20, 2003, 10:56pm Subject: Re: Tea - power usage (approximate)
MTBF doesn't mean much in some circumstances. Computer hard drives use/used ball bearings with very consistent MTBF levels having to do with metal fatigue after >10,000 hours. If the computer is on 24/7 the 10k hour mark will simply come along sooner. More pointed example is the cheesy fans that predictably go bad very quickly on a computer that's always on, and rarely malfunction on grandpa's Dell.
I guess my point above is that the benefits of running equipment 24/7 need to be weighed against the negatives. On the Isomac, the pressurestat contacts probably have a finite life based on the number of cycles (+/- 1400 / 24hr. of operation), as do the boiler and other pressurized components. Cutting the number of cycles on the boiler pressure adds cycles to the pressurestat and hours to the heat on the natural rubber o-rings and plastic Y's. Help one thing, hurt another.
We're making the same bet, just on different components.
As to having a machine that is always ready to run, that would be cool.
Total power for the first hour of 'warming up' is roughly 0.36 kwh
24/7 consumption (using the 'equilibrium' on-off timing) is 1.3kw*(10/114)*24hr=2.7 kwh/day.
Dovetails nicely with your results, eh? I did this experiment a while back before adding insulation (1/2" foil-sided solid foam). That increased the interval between cycles from around 70 seconds to 114 seconds. It largely defeats the cup warmer, but I don't mind and the kitchen stays cooler in the summer. I also confirmed that it was fully warmed up after 35 minutes.
Considerable agreement Dan, especially considering the pressurestats and water level probably aren't set the same. I'm tucking the 35 minute warmup away as a permanent mental note.
The insulation sounds like a good idea. I haven't because I'm lazy, don't really have time to add a project, and was afraid that bulky insulation would make things more of a tight squeeze.
The Intermatic (Home Depot special) timer is great - set earlier weekdays, on twice daily, once on the weekends, and even I can program it without an instruction book.
In our house, the tradition is that I make breakfast for everyone on Sunday morning. Today, while doing this, I found a spare time project .... drumroll please...
Posted Thu Mar 4, 2004, 1:44pm Subject: Re: Tea - power usage (approximate)
I may be wrong about this, but I have assumed that the heat generated by an espresso machine left idling all day goes into the house and partially offsets the need for other heating. If true, this would mean that the cost of leaving your machine on 7/24 is not as high as calculated. However, during aircon season, the machine not only consumes energy, but dumps excess heat into the home that must then be removed by the air conditioner.
Posted Thu Mar 4, 2004, 8:55pm Subject: Re: Tea - power usage (approximate)
Rick Said:
However, during aircon season, the machine not only consumes energy, but dumps excess heat into the home that must then be removed by the air conditioner.
Hamm Senior Member Joined: 22 May 2003 Posts: 509 Location: Kettering, Ohio Expertise: I live coffee
Espresso: Isomac Tea Grinder: Mazzer Mini Vac Pot: I'm not that kind of guy... Drip: From the faucet occasionally Roaster: La Terze Roasterie,...
Posted Fri Mar 5, 2004, 5:48am Subject: Re: Tea - power usage (approximate)
Here's my take:
I've been leaving the Tea on 24/7 because the heating element seems to run a LOT more from a cold start. Now that Ted and Dan have done some math, I'm not so sure.
Personally, I'm all about doing whatever will reduce overall energy consumption, but then where you try to cut a few corners, you wind up tearing hunks off somewhere else. The thought of American needing the output of entire power plants just to run idle equipment is astonishing to think about.
So I took a look, and I think I've figured out why my utility bill is so high:
Tea is on 24/7
We leave our porch lights on all night
My computer is on 24/7
My computer and music gear is hooked up through power conditioners, which require electricity in order to "condition" the power
We have the crappiest windows on our house. Even though they're less than 5 years old, the previous owner bought ones glued in with monkey spit, which explains why our kitchen window mysteriously shattered the other night. But that's another story.
But then I get to thinking that us coffeegeeks got into this because we want the best espresso experience. We should've known what we were getting into when we bought our gear. Most of us are probably not that concerned with the exact amount of juice need to power our stuff, as long as it amounts to a few dollars or less on our utility bills. And in the end, if I corrected all my "problems" listed above, I might save $5 a month. Doesn't seem like much. But over the span of several years, it adds up...
So it falls back on a philisophical principal. In modern society, Americans at least are guilty of the creating the laws and rights of convenience and excess. Many of us feel we have the RIGHT to drive 10 mph over the speed limit. Or to be able to get through the Wendy's drive thru- window in 4.5 nanoseconds. Some of us expect to get the best parking lot spaces, have short lines at the bank, use our cell phones whenever we feel like it (such as during eye surgery, ) and have the right to slack off at work, be lazy and still get paid for it.
So for me personally? I'm sick of allowing myself to fall victim to those very things I mentioned, which I HAVE done all of before. So I intend to do my best to solve the utility bill mess, and just enjoy my espresso! It's a part of my lifestyle I don't mind spending money for. As long as I keep it in check and don't allocate my Roth IRA funds toward it, it's OK.
So if there really is a point to all this, it's that I appreciate the work that went into figuring out the power consumption of typical high-end machines. It has helped me to get a better grip on the thought process that goes into living with modern conveniences.
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