Posts by marie

Tesla Announcement April 2015 is Woefully Incomplete

Posted by on May 1, 2015 in Blog | 3 comments

In Tesla announcement April 2015, Elon Musk just unveiled his plan for the future of energy.

According to Elon,┬áthe future of energy will continue to put BTU’s and KWH’s in the same bag and seek to transition the world to renewable energy via solar P.V. and wind.

Fourteen minutes into his presentation Elon describes how many of his batteries will be needed to accomplish this fossil fuel free future. Since I am fairly certain that this analysis meets the space conditioning and water heating demands with a 1-1 electrical aspect I am guessing his estimate is off by at least 50%. In other words, if site-sourced thermal energy management was included in the analysis then much fewer KWH would need to be generated and stored to meet the BTU demands.

I share Elon’s desire for a fossil fuel free future and I agree that distributed electrical storage and site generation will be a part of that architecture. However, any grand scale vision that completely ignores the difference between thermal energy and other end uses is, I think, woefully incomplete.

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Room at the table? Whose table?

Posted by on Apr 30, 2015 in Blog | 0 comments

As I’ve said before, I get the same arguments over and over again from the two main industries that have established positions that we deviate from. The geo industry acts as the arbiters of how water source heat pumps are applied and the solar thermal industry acts as arbiters of how solar thermal collectors are applied. There is no shortage of furrowed brows when thermal battery applications are being discussed. In essence, each one wants us to justify our seat at their table.

I am not playing that game. I don’t feel any need to justify our applications in their existing contexts. We are defining a new context. The new context is source energy management. In this new context, the old applications are obsolete. The context is not a GSHP plus a solar thermal system. The existing industry experts are not capable of rendering a verdict on thermal battery based source energy management systems. They’ve never experienced them.

I will not use a single source system frame of reference in a defense of a multi-source system. It makes no sense. Take the “Solar Thermal is Dead” article in Green Building Advisor as an example. Since the context of that article is based on the current solar thermal industries applications I can’t find all that much to disagree with. Change the application and the conclusion would be entirely different. However make the application look like advocating adding the current context “geothermal” heat pumps to current context solar “hot water” and that sounds like an expensive and complex system with merit that is marginal at best. Good thing that is not what we’re talking about.

Context is everything. The table we are already sitting at is called source energy management. If the other trades would like to come join us we’d be happy to have em.

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Energy management ought not be an afterthought.

Posted by on Apr 13, 2015 in Blog | 0 comments

If you look at the HVAC industry you’ll find that energy management is not an accurate description of what they “do”. In rare cases some version of it happens but really only as an add on to an existing systems controls. “Control” can mean many things and what it generally means to the HVAC industry is “it functions”.

Now that we have this emerging world of connected devices the optimized management of energy, rather than the control of the system, ought to be the focus.

As a small example, it is up to the HVAC installer to set the set-points and the differentials on a boiler or a heat pump (and size the equipment to begin with).  The goal is to limit short cycling but still provide adequate supply temperature to the distribution (and capacity). Sometimes this includes an outdoor temp factor, sometimes not. The point is that wherever the set-points and differentials are set will affect the system performance but all the customer usually knows is if the system is functioning or not. Also, the contractor may be doing what he thinks is best but there is rarely any objective measure in place to verify the performance is optimal.

Even when systems do have data logging and are being monitored and controlled effectively consider that they are still generally “blind” designs to begin with. In other words, they were not modeled and optimized on software prior to being configured in the physical world. So they may be effectively managing what they are, but really the design is somebody’s guess. Who’s to say the configuration is ideal if you don’t have anything else to compare it to?

This becomes all the more relevant when systems are multi-source/sink and have thermal storage elements. The room for optimizing a design is significant and so is the possibility of poor designs and mismanaged control.

Software defined pre-configured configurations and a management service to support them is the future of HVAC.


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R.P.A. Interview

Posted by on Apr 9, 2015 in Blog | 0 comments

Back in November we had the great honor to present to the Radiant Professionals Alliance. Our interview with Mark Eatherton and Dave Yates is over two hours long and is the second presentation we’ve had with the R.P.A.

We discuss the economics and benefits using water/ice as a latent capable thermal battery energy storage system.

We welcome any questions or comments about the interview below.

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How much energy is there in one vertical ton of earth loop?

Posted by on Apr 8, 2015 in Blog | 0 comments

Imagine a column of rock that is 200′ tall and has a 15′ radius. The volume of this column is 141,428 cubic feet. Converted to cubic yards / 27 = 5,238 cubic yards. Lets say that this particular rock weighs 3,500 lbs per yard. This means the column weights 18,333,000 lbs.
Lets say that it has a specific heat of 0.25. This would mean that this column of rock would have a thermal capacity of 4,583,250 BTU per degree.

As we know, we cannot “pull” on this entire column at the same time with a single bore hole in the middle of it. We will create layers of differential temperatures as we suck the heat from the center of it. We are “done” when the first radius of earth outside the borehole has been lowered to a temperature that is too low to support a high enough differential into the loop pipe.

Lets use 25F as our minimum fluid temp and lets say that the first radius outside the borehole allows the fluid temp to drop to 25F when it reaches 38F. If that were the reality of the situation then I would say that this could represent the bottom of the capacity of the borehole.

But what if we slow down the flow of the fluid? If we do that then we can keep “mining” the borehole even after the first radius reached the “bottom” of the operational capacity.

How can we slow down the fluid and not shut down the system? By using a thermal battery we separate time direct requirements from cumulative totals.

So if we put a constant slow pull on the bore hole and such heat out of that rock column… how many BTU do you think we could get?

Lets say that over the three coldest months of the winter the deficit energy (not provided by solar input) is 24 million BTU over 90 days.

The rock column would have to give up about 5.24 degrees across its entire mass to do this. Could it do it? If it did it would have delivered an average of 11,111 BTU per hour into the system for the entire 90 days. This seems too high to me and I would tend to doubt that we could expect this arraignment to keep up.

The problem is that we keep doings that we expect to cause system depletion and we keep getting surprised by the results.

Thoughs or questions? Comment below.

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