ETS

[Larry Lunsford]

I recently learned about a device that may be of interest to some glass artists: ETS (Electric Thermal Storage). An ETS is basically an insulated box, filled with bricks. It has heating elements and a fan to blow air through it. The heating coils heat the bricks during times of off-peak electricity rates. Blowing air through the ETS releases heat in the home as needed. ETS units are fairly expensive and they generally only make sense if you heat your home with electricity and you have a significant difference between peak and off-peak electric rates (sometimes called TOU - Time Of Use billing).

I know some glass artists have to deal with Demand Metering. With demand metering, you not only pay for the electricity you use (kilowatt hours) but you also pay for your peak load. Your peak load may only last for a few seconds out of a month, but you pay the same (and usually substantial) surcharge whether the peak lasts a few seconds or the entire month. With demand metering it may make sense to use an ETS that draws the same power as your kiln and modify your kiln controller. The kiln controller would be modified so it switches power between the kiln and the ETS. Instead of simply turning the kiln elements on and off, it would switch the load between the kiln and the ETS. Given the fairly rapid cycling that happens with a kiln controller (elements are turned on and off every few seconds) it would probably not be advisable to try to share power between a kiln and other types of heating and A/C devices.

An ETS doesn’t make sense for most people. I hope there’s a glass artist to two out there that can benefit from this.

Larry Lunsford

[Bert Weiss]

Larry

I have seen heating systems with an active solar system. In the summer, mirrors are faced (with motors) to the sun and collect heat, which is transferred to barrels of inert liquid in an insulated cellar space. Then in the winter, the heat from that cellar is released in to the house. A home on the coast of Maine with this system, never went below 50º all winter long with no added heat.

The home was not being occupied in winter, and there was a recording thermometer inside.

[Larry Lunsford]

Hi Bert.

I was thinking of you when I made this post. I remember you mentioning that your studio has some form of demand metering.

Funny you should mention solar heating. My wife and I recently bought a piece of land in Pagosa Springs (south west Colorado). I found out about ETS from the electric company there. We plan to retire in Pagosa Springs in a few years. We're currently planning to cover the south wall of the house with flat plate solar collectors to heat the house. Current plan is to build a 20,000 gal water tank under the garage. That'll hold enough heat to get us through several very cold days. I can't imagine how big the tank would need to be (and how thick the insulation) to store enough heat to get through a dreary New England winter.

Now if I could just find a cheap way to use 160F water to run a generator that can power my kiln!

Larry

[Bert Weiss]

I managed to lose my demand meter. Several years ago, I shut the studio down for a short time and when they went to reactivate it, the meter was broken. So they put a regular meter back on. Now a firing costs about $15 instead of $150.

[charlie]

would an ets stay hot enough for fusing temps?

for your new house, look at passive solar heating panels. basically a box with a hole in the top and bottom of the back plate, painted black, with the face being glass. the holes in the back go into the space to be heated. the box heats up the air, creating convection, blowing hot air out the top hole into the house, and sucking cold air in the bottom hole from elsewhere (ducted) in the house.

http://www.iedu.com/Solar/Panels/

really easy to build and install. free heating. doesn't work so well in the hot time of the year though. you do need south or southwest facing walls.

[Bert Weiss]

would an ets stay hot enough for fusing temps?

for your new house, look at passive solar heating panels. basically a box with a hole in the top and bottom of the back plate, painted black, with the face being glass. the holes in the back go into the space to be heated. the box heats up the air, creating convection, blowing hot air out the top hole into the house, and sucking cold air in the bottom hole from elsewhere (ducted) in the house.

http://www.iedu.com/Solar/Panels/

really easy to build and install. free heating. doesn't work so well in the hot time of the year though. you do need south or southwest facing walls.

Up here in New England the most efficient passive solar panels preheat water for either hot water or heat. In the summer it is just for hot water, in the winter for both. There is no way to store much of it though, other than a large insulated tank.

[Larry Lunsford]

An ETS does get hot enough to fuse glass. The guy at the power company told me that they get to around 2000F max temp. BTW the ETS are fairly compact - the unit I saw was about 2' x 2' x 1'. They store a lot of heat because they use electric elements which can get really hot and bricks (which can tolerate high temperatures) to store the heat. With solar, you can't generate as high of temperatures (not easily or cheaply) and if you're using water to transfer and store the heat, you're limited to temps of below 212F.

Unfortunately, a standard ETS has no empty space inside to fuse glass or a lid to get access. It also does not heat/cool as you would want for glass.

The most practical way to combine glass fusing with the benefits of an ETS is to time your firings so the maximum on period is during off-peak electric rate hours.

Larry