Electricity Usage Monitor - Page 2

[cafeIKE]

<rant>
Absolutely correct. And regardless of whether you choose to leave the machine on 24/7 or turn it off at night, boiler insulation is a no-brainer. Uninsulated boilers waste energy, pure and simple. Insulating the boiler should not be the responsibility of the consumer; espresso machines should ship with insulated boilers. Unfortunately, most manufacturers (with the notable exception of Quick Mill) don't agree.
</rant>

Here's a load of marketing bollox to go with your rant:

a) Insulating the boiler would disrupt the natural airflow inside the espresso machine. With an un-insulated boiler, heat will rise normally upwards not only to pre-heat the cups, but at the same time create an upward draft to keep the bottom portion, where the electrical components located, cooler. When the boiler is insulated, less draft is created inside, heat build up increases due to more stagnant airflow. This will ultimately affect the electrical components, such as the smaller pressurestats and brain units (especially when located very close to the boiler).

b) Even with the boiler walls insulated, the stagnation of heat will still affect the water reservoir, and

c) For boiler insulation to become completely effective in not allowing heat build up against the reservoir, all the tubing inside should be insulated and an electrical cup warming plate should be added. If insulation is added to the wall between the reservoir and boiler, this will only increase the temperature of the stagnated airflow.

These are the reasons why many manufacturers do not insulate their internal boilers.

[AndyS]

<rant>
Absolutely correct. And regardless of whether you choose to leave the machine on 24/7 or turn it off at night, boiler insulation is a no-brainer. Uninsulated boilers waste energy, pure and simple. Insulating the boiler should not be the responsibility of the consumer; espresso machines should ship with insulated boilers. Unfortunately, most manufacturers (with the notable exception of Quick Mill) don't agree.
</rant>

Sorry, I remain unconvinced by your rant.

The Home-Barista.com community has embraced HX technology with great enthusiasm. Unfortunately, energy conservation is the last thing on your minds, because heat exchangers for home use are energy wasters. The amount of energy dumped down the drain prior to each shot is probably greater than the amount of energy that goes into the shot. You guys with the HX machines can work the figures a lot better than I, but I'd guess that the energy wasted in flushing prior to a slow-paced series of daily shots is in the same order of magnitude as the energy that could be saved through insulating a machine that is on only a few hours a day.

Also, to be fair to the manufacturers, remember that much of the waste heat from uninsulated boilers is used for keeping cups warm on top of the machine.

In addition, engineers interested in really precise control of boiler temperatures know that insulation makes it much more difficult. It has been discussed here previously that "lossy" boiler allow better temperature control. Of course, this isn't much of an issue if you're OK with dumping excess energy down the drain.

In conclusion, it's clear that for the home barista, convenience and style are more important than energy conservation. Otherwise, they'd still be using their Silvias.

[AndyS]

I'm relatively positive longer on times reduce group gasket life, based on personal usage observations. And it makes sense that rubber gaskets harden faster at higher temps.

I agree it makes sense, although we're not looking at real data. Also, the old-style LM Lineas had gaskets between the brew boiler and group "neck" that supposedly lasted longer when the machines were on 24/7.

[HB]

The Home-Barista.com community has embraced HX technology with great enthusiasm. Unfortunately, energy conservation is the last thing on your minds, because heat exchangers for home use are energy wasters.

Actually, my concern is the heat an idle espresso machine introduces into the room. The temperature of our kitchen raises several degrees if the split doors leading out of the room are closed. Prior to insulating the boiler, the temperature difference between the front of the house and the back of the house was intolerable in the summer if the espresso machine was running for more than a couple hours.

[cafeIKE]

In addition, engineers interested in really precise control of boiler temperatures know that insulation makes it much more difficult. It has been discussed here previously that "lossy" boiler allow better temperature control.

Care to edit your post to include links to the threads?

If one goes to the end stop, a perfectly insulated boiler would require no regulation what so ever.

If the energy input is scaled / controlled to the energy loss, shouldn't insulation always be a plus

As far as the cups, the difference in temperature between an insulated and uninsulated boiler is probably a very small portion of the energy saved. On the Vibiemme, insulation changed the duty cycle from about 1 in 15 to about 1 in 45. The change in cup temperature in about -5°F vs uninsulated.

All that being said, I think the reason boilers are not insulated is purely economic.
I'll probably never recover the cost of the boiler insulation from the energy saved.

Assume 1.6kW heater.
Assume duty cycle goes from 6.6% to 2.2% after insulating
Assume 3 hours use per day
Assume $0.10/kWh [May 07 LA DWP Residential]

Ignoring cost to heat initially, shot and flush water.
Cost = Draw * Duty * Time * Rate
Pre insulate cost per day = 1.2 * .066 * 3 * .10 = $0.03168
Post insulate cost per day = 1.2 * .022 * 3 * .10 = $0.01056

Savings per day = $0.0213

Say $75 for insulation and bits. I work for free.
About 9.5 years to pay back at current rates. Less, if DWP keeps raising rates.

[AndyS]

Care to edit your post to include links to the threads?

If the energy input is scaled / controlled to the energy loss, shouldn't insulation always be a plus

Well, maybe "discussed" wasn't accurate. It was "mentioned" here. And it is obvious to everyone who has manually tuned the PID control for an espresso boiler that getting RID of heat is the major problem.

Although it is quite feasible, I know of no production machine that uses feedforward control as you suggest (although some have used it experimentally).

I think the reason boilers are not insulated is purely economic.

You are undoubtedly correct. Most of the people building espresso machines could give a rat's ass about the temperature issues we tend to obsess about (although in the last few years this situation has changed).

[RapidCoffee]

The Home-Barista.com community has embraced HX technology with great enthusiasm. Unfortunately, energy conservation is the last thing on your minds, because heat exchangers for home use are energy wasters. The amount of energy dumped down the drain prior to each shot is probably greater than the amount of energy that goes into the shot. You guys with the HX machines can work the figures a lot better than I, but I'd guess that the energy wasted in flushing prior to a slow-paced series of daily shots is in the same order of magnitude as the energy that could be saved through insulating a machine that is on only a few hours a day.
...
In conclusion, it's clear that for the home barista, convenience and style are more important than energy conservation. Otherwise, they'd still be using their Silvias.

Hey, it wasn't labeled rant for nothing. Agreed, there isn't much about this obsession hobby that makes sense, from an energy standpoint or otherwise. But HX machines offer a capability that Silvia does not provide, that is, to deliver both water for brewing and steam for frothing milk simultaneously. The only fair comparison is a double boiler machine, which might or might not be more wasteful of energy. I suppose it would depend on the relative boiler sizes and the amount of flushing required.

We now return you to your regularly scheduled speculation...

[AndyS]

Actually, my concern is the heat an idle espresso machine introduces into the room. The temperature of our kitchen raises several degrees if the split doors leading out of the room are closed. Prior to insulating the boiler, the temperature difference between the front of the house and the back of the house was intolerable in the summer if the espresso machine was running for more than a couple hours.

Wot, no A/C?

Willis Carrier invented air conditioning so that people could leave their uninsulated home espresso machines on all day.

(just kidding)

[cafeIKE]

And it is obvious to everyone who has manually tuned the PID control for an espresso boiler that getting RID of heat is the major problem.

Sorry if I'm dense, but I don't understand the above statement.

[AndyS]

You're not dense, I wasn't clear about it.

The PID control compares the actual boiler temperature to the desired boiler temperature and adjusts power to the heat element accordingly (that's an oversimplification, but it's OK for this discussion).

When the actual temp is too low, the heater brings it up relatively fast, usually in a few seconds. This results in good control.

When the actual temp is high, the only thing the controller can do is to stop adding additional heat. But the boiler doesn't respond quickly. It slowly drifts downward in temperature. Typically an uninsulated boiler loses temperature (when the heater is turned off) 5 or 10 times slower than it gains temperature (when the heater is on). This sluggish response makes precise control difficult.

Insulating the boiler probably means that the boiler will drop in temperature 15, or 20, or 25 times slower than it gains, making precise control even more difficult.