Thanks for taking the time to explain your project. Yes, warm floors make a big difference. A tight and well-insulated envelope also pretty much eliminates cold spots.
2x12 framing sounds expensive, especially if fully supported by a 12" thick foundation. If you are doing the work yourself, you might consider 2x6 24OC or even 2x4 16OC over a normal 8" thick foundation with Larsen trusses outside. I like 2x4 16OC because cheaper 1/2 drywall inside works fine, whereas with 24OC, 5/8 drywall is advisable. The stud wall gets ZIP sheeting and tape on the outside. This layer has minimal penetrations, thus becomes a convenient air barrier near the inside wall, which is appropriate for a heating dominated climate. The Larsen trusses are made of 2x2 flanges and OSB web sections spaced apart to reduce thermal bridging. The trusses can be 12", 16" or 24" to make efficient use of the OSB. The trusses, being nonstructural, hang out past the foundation. The foundation is insulated on the outside to flush with the outer surface of the trusses. The sheeting on the outside of the trusses can be ordinary OSB and need not be taped. Tyvek, rain guard and siding complete the wall. No need for expensive foam board.
A double stud wall also allows as thick a wall has you want, but may require two foundations, depending on local codes.
I see VIP's as a big deal for high-performance remodeling. Adding, say, 1" VIP's would be easy, whereas much thicker foam or Larsen trusses may require lengthening the roof to cover them. Windows are the short circuit in a high-performance building, so I can't wait for aerogel to become economical.
Original Message:
Sent: 03-16-2023 10:56 PM
From: william fitch
Subject: What are some technologies that you would like to see covered more in Solar Today?
The relationship of the sun area to the master area is really like one big room, 16 feet to the top but only a 7 or 8 foot divider wall. They are more split level in relation to their respective floors. In terms of masonry floors, even a 70-75- DegF floor is way nicer that 60 deg F floor even id the radiant benefit is small. SO I look at the piping as a comfort plus at a min..
The piping in the sunroom floor will be only 1"-2" or so below surface where as the master probably midway 4". Goes to time delays, etc.. Insulation will be a combo of foam board and rockwool, 2x12" 24"OC framing, sets high limit on R value...
I would love to use VIP's in the walls or Aerogel, etc.. at least in part for R- 100, but not a millionaire...
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william fitch
Owner
www.WeAreSolar.com
Original Message:
Sent: 03-16-2023 06:37 PM
From: M Keith Sharp
Subject: What are some technologies that you would like to see covered more in Solar Today?
Bill,
Do you have an overall UA value? I have found that a peak loss of 10 W/m^2 (the Passivhaus standard) before considering internal heat gains is a pretty good place to start. This ends up being a bit better than Passivhaus after internal heat gains are added. I had to use higher R-values in my climate (~8000 degree F days), but you may be in the ball park for the PA climate. We used triple pane windows and needed to limit the areas, because the window loss became about half the total. Tight air-sealing and energy recovery ventilation were also necessary to keep the loss small.
Zola, and possibly other companies, make quadruple pane windows. We did not use them due to the expense, but they would have improved performance significantly because of the fraction of the loss represented by the windows. Years ago, I saw a house that used two double-pane windows in each location. This was before triple-pane were even available. Pretty innovative for the time.
Just curious, why not greater R for the ceilings? If you are using trusses, it is cheap and easy to increase R by just blowing in more cellulose. Just be sure to design tall truss heels so that the depth is maintained over the supporting walls.
You probably know, but the first 4" of concrete is more effective than the second 4" (for your 8" floors). It might help to distribute some of that extra concrete to other surfaces. To get to 100% ambient conditioning, I would guess that you need more mass, based on the cloudy PA climate. The building time constant probably needs to be several days. Just let me know if I can do simulation results for you.
We also put pipes in the two floors, but have not circulated them yet. Half or more of our solar gain is downstairs, yet the house still stratifies (hotter upstairs) by natural convection. The only path for circulation is an open stairway between the two floors. I wonder if you will find the same, even though your sunroom is downstairs (if I understand correctly). You may regret spending the money imbedding the pipes.
I bet shades would work nicely to reduce overheating in your climate. With our very small cooling load and low nighttime temps, overhangs on south glass have been marginally effective. Still considering shades for east glass if and when we experience overheating.
Best,
Keith
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M Keith Sharp
Emeritus Professor
Louisville KY
Original Message:
Sent: 03-15-2023 12:53 PM
From: william fitch
Subject: What are some technologies that you would like to see covered more in Solar Today?
The sunroom is the active solar area with about 8" of concrete floor, R-30'ish underneath. There will be radiant tubing in this floor, not to give heat but to take it away. The upper slab which is also about 8" think is part of the same radiant loop below. Its an experiment really. The concept is that a low velocity almost constant water circ through the loops will transport a good deal of the collected sun energy below from the lower slab and transport it to the upper slab for night time radiant heating. The two spaces will be open over the top of the connecting wall with low velocity "Big Slow" fans, one in each space for an very slow active air circ between the two spaces, adding convective equalization to the equation. A split HP unit basically powered all by solar will provide any gaps in heat or AC over the course of a year. Should yield very low production and duty cycle though. All the R-values will be 50 or 60 for walls and ceiling. Windows I am trying to get the highest glass I can find. The glass expense alone will be huge. Gave up on VIG's. Would have loved to try that in the mix... Also was looking into high specific heat and higher thermal transfer rate concrete, like the stuff made by HeidelbergCement (Powercrete) for HVDC lines, but the cost per ton is literally thousands of dollars. Slightly over my budget.
https://www.youtube.com/watch?v=_YkhlLtVkcI
Basically a passive thermal sunspace with High R and a few extras....
I may end up adding high R value automatic nighttime tracked insulation shades to the main sun windows for greater reduction in nighttime energy loss. With VIG's I would not have needed that, high R reg glass, I will see once the space has been functioning for a couple of years...
.....Bill
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william fitch
Owner
www.WeAreSolar.com
Original Message:
Sent: 03-15-2023 12:35 PM
From: M Keith Sharp
Subject: What are some technologies that you would like to see covered more in Solar Today?
Bill,
High R-value and sunroom sounds good. How much thermal mass are you including? A slab-on-grade floor insulated underneath can provide a good part of it. Low envelope losses, just the right amount of solar gain and sufficient thermal mass are the keys to reaching 100% ambient conditioning. You obviously know what you are doing, but if you would like me to simulate your addition to predict its performance, I would be happy to. Let me know.
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M Keith Sharp
Emeritus Professor
Louisville KY
Original Message:
Sent: 03-08-2023 12:10 PM
From: william fitch
Subject: What are some technologies that you would like to see covered more in Solar Today?
I am going to try and keep this very focused. The first two paras of your reply are basically true.
I was shall we say heavily involved back in the 80's building a Super-insulated house. Ironically, we blew the attic and walls with cellulose and used a 6mil poly vapor barrier, etc.. All those thermal concepts you refer to are pretty much ABC's in thermal engineering of buildings... The "ASHRAE Fundamentals handbook" covers all this and far more in detail. Kind of a "bible" back then (80's) and probably still is today, along with "Solar Thermal Engineering" by Peter J Lunde and "Solar Engineering of Thermal Processes" by Duffie and Beckman, both of which I have far to much scribbling in.
"Not sure what you mean by "structural losses".
I meant nighttime direct cooling through the structure, which really only occurs through low to moderate insulation houses. Active night time cooling (Bringing in outside cooler air) has negatives associated with it. Higher humidity at night, pollens higher, local pollution like wood burners (Smoke) etc.. Active nighttime cooling via HP maintains the internal "clean air" and humidity levels and indoor temp stability. I have used non HP nighttime cooling via many different ways, and they are all very variable. And with global warming effecting the overnight lows BIG TIME, the cooler nights are not so cool anymore during Summer, in cities almost non existent (Heat Islands).
Regarding the PV array size, you must include EV driving. I use as I said approx 8 to 10 MWH a year for travel alone (Not counting external chargers). And I would not say we drive a huge amount. The reality with the REAL energy for EV miles is not the Guess-O-Meter in the car, but putting a power meter on the breaker line that powers the charger, using the odometer and doing the simple division. When you do that in a climate that has Winter, you get about 2.5 to 3.2 miles per KWH seasonal averages. SO, if you drive 25 to 30K miles a year for all the EV's combined, you wind up about where I mentioned, 8-10 KW of PV array for EV. Now, if I remember you actually live in CO now, which is sun heavy compared to central PA. So your PV's arrays for energy are going to be quite a bit smaller than allot of other places, including mine. And if you live high, 1 mile say, you will get 10 to 15% more on top of that.
As I mentioned, I used all of my 20.5MWH last year and I basically cover most of my heating with active solar of one form or another and GSHP. Your internal load will very HUGELY by number of occupants, and age (Teenagers, etc.) and the kind of things you do inside, how much time you spend at home (Also huge impact) and many other variables. As global warming continues, heating loads will become non-existent and the life saving actions will all be about keeping cool, and unfortunately this won't take 50 or 60 more years for everyone to feel first hand.
Concluding, a high R value structure is probably the best place to put new building dollars in terms of ROI AND COMFORT. Remodeling and retrofit is in reality crazy expensive. I do my own re-modeling because I basically know how to do everything, plumbing, elect, framing, etc.. when I can do it with just ME. I just priced a Masonite interior door 1-3/4" thick, 34" x 73", 15 glass lite, light Oak, pocket hung, for the downstairs bathroom I am trying to finish. $1500.00 from Lowes for the door alone. I never thought I would spend $1500 for a bathroom door. It's frankly nuts! I am also putting on a 900 sqft super insulated addition, Master bedroom/bath and sunroom combo, my own design. I will be lucky to get away under 50K$ NOT counting ANY interior furnishings or fixtures......
And at night time I thank god I don't live in CA or equiv., for the cost alone....and the fact "they" would not let me do anything myself.... without the "proper papers" most likely... LABOR $$$$$$ more....
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william fitch
Owner
www.WeAreSolar.com
Original Message:
Sent: 03-08-2023 10:07 AM
From: M Keith Sharp
Subject: What are some technologies that you would like to see covered more in Solar Today?
Bill,
This is a great discussion, and thanks for asking questions that I am sure others have as well.
Internal heat generation is a small, but significant, contributor to serving the heating load in the winter. Paradoxically, energy efficiency is counterproductive in the winter, since any reduction in internal heat generation from your induction vs resistance cook top, etc. just increases the energy that must be met by other sources to keep the house warm (heating energy = envelope losses - internal heat gains). In the summer, it's the opposite. Cooling energy = envelope gains + internal heat gains.
Not sure what you mean by "structural losses," but I have heard some advocate that insulation is bad in the summer, because it doesn't let the internal heat gains out. This is wrong, because during the summer, outdoor temperature is higher than indoor, if the house is working properly. Heat transfer is always from hot to cold, so the house is gaining energy through its envelope. This gain, plus the internal heat gains, must be met by the cooling source, whether passive cooling or other. Passive nighttime ventilation can serve the entire cooling load in all US climates, though it is challenging in hot climates like Phoenix. TMY weather for Phoenix has about 50 days of outdoor temperature above the comfort range, so a 100% ambient-conditioned building needs lots of thermal mass to bridge this interval. On the other hand, sky cooling is available for nearly every night even in Phoenix and allows much smaller thermal mass to suffice.
You make a good point about new and existing buildings. Buildings are expected to double by 2060, so if every new building was built to Ambient House standards, then we would solve less than half the problem of the IPCC target of zero carbon emissions by 2050. Existing buildings must be addressed, too. Existing buildings can absolutely be remodeled to Ambient House standards. Added insulation and thermal mass, air sealing and solar gains are the main components. For new passive solar homes, Balcomb estimated the added cost as 4-8%. In 2011, Jim Riggin's nearly 100% ambient conditioned house cost about 1% more. With 100% solar water heating and enough PV for net zero, it was 10% extra. I have no data on remodels, but one could expect the increment to be a bit larger if the foundation and structure are not modified.
Some climates are easier than others. Los Angeles, for instance, is so temperate that little to no extra thermal mass is needed, just a bit more insulation and a little solar gain. Concrete (for thermal mass) is expensive, but cellulose insulation is one of the cheapest building materials. Solar aperture areas for modern Ambient Houses are much smaller (6-8% of floor area) than historic passive solar homes (some were 100% or more of floor area). Our house has smaller, high-performance windows compared to conventional construction in the mountain west, which includes larger, lower-performance windows, so that cost is about the same. This at least part of the reason that the cost increment of a modern house like Riggins' is smaller than for historic passive solar homes. We also use less of the expensive concrete.
I am certainly not saying that ambient thermal sources can do everything, but they can serve up to about 90% of building loads (heating cooling and water heating alone are about 75%). The choice for zero carbon is between 10-20 kW of PV and a huge bank of batteries for a conventional house, or Ambient House and 1-2 kW of PV and a small bank of batteries. The most economical choice is pretty clear for new buildings and many remodels. There are, of course, special circumstances, especially related to solar access, that could change the comparison or prevent passive solar and PV altogether.
------------------------------
M Keith Sharp
Emeritus Professor
Louisville KY
Original Message:
Sent: 03-07-2023 03:20 PM
From: william fitch
Subject: What are some technologies that you would like to see covered more in Solar Today?
Humm.
Let's see:
Going back to this from your earlier post on this thread:
"By maximizing locally harvested ambient energy, the electric grid necessary for serving the remainder of the load for buildings could be smaller in 2050 than it is today."
This was of course part of your concern that just expanding production with RE will not be able to, "Get the job done" within time parameters.
As you noted, all these "super-insulated" structures with RE "accessories" can reduce heating losses to negligible. That of course is great in Winter (For those that have it), but those BTU's gen'ed by internal occupancy and electrical loads becomes cooling load in non Winter months. In short, a "super-insulated" house becomes cooling loads, not heating.
Passive cooling will only take you so far without structural loss to help. Most of the remaining variability that will be incurred will be a function of occupancy numbers and their direct total use loads, plus transportation.
As you note, all these designs have to be done at the new construction level. Currently there are about 130 million households as of 2022. In 1960 there were about 53 million. That is a rough increase of 2.3 fold over 63 years. This occurred during the baby boom time and a relative population growth rate that hopefully won't be continued for the next 63 years, otherwise we will be in big, big trouble that we won't be able to "build" ourselves out of.
So my point is that I don't see your time constraint concern for reductions being served by new build out when there is a legacy of 130+ million homes which practically speaking cannot be incorporated into the Super design group. Even if all new houses as of today were of the "super" class (cannot happen due to cost), 50 years from now there will still be a preponderance of legacy homes plus all that is new.
Building "super" class homes can certainly help the problem and should be done as much as possible, but forcing such homes to be built at greatly elevated frontend cost (Due to code and regulations), would make every state in the USA have the housing cost of CA. And just speaking for myself, I could no more afford a single family dwelling for myself, let alone a family of four with 3 EV's in CA, than I could grow a second D*ck. The end result of such a forced housing situation would begin, I am afraid, to resemble the movie version of 1984, due to the continued wiping out of the middle class in this country and accelerated wealth inequality.
The rich would have their "super" class houses, the rest would be stuck in block housing. I am not being dramatic here. When looking at engineering solutions, one must not be an "Oppenheimer" with super siloed blinders focused only on the Atom, never giving one thought to how that will effect society globally, once unleashed. We don't want to end up the classic Hollywood moment saying, "I was there for the Science" or the Engineering, all else being someone else's problem because it was not MY JOB.
To conclude, I think the only practical solution (Due to legacy) is accelerated real ramp up of RE production and improved efficiency, which could do the job, but won't be allowed to because of conventional energy entrenchment and its associated wealth and political power.
Sorry, I don't mean to be a wet blanket, but I look at problems from all connections and strip away all wishful thinking.
BTW: Good luck and have fun at the ASES conference this summer.
------------------------------
william fitch
Owner
www.WeAreSolar.com
Original Message:
Sent: 03-07-2023 01:32 PM
From: M Keith Sharp
Subject: What are some technologies that you would like to see covered more in Solar Today?
The PV math is different for Ambient House. Our house is about 3500 sqft. In 2022, we used no auxiliary energy of any kind for heating or cooling, other than a few fires in the fireplace. The house is otherwise all-electric and we used about 4000 kWh for the year. PVWatts says a ~ 2 kW system would get us to net zero. With solar (thermal) hot water and a few other things, 1 kW might do it.
Ambient House is super-insulated and passive solar and passive cooling, but it also is more than that. It is bringing all of this together and designing the house from the very beginning to require no energy for space conditioning other than what is available in its microclimate. No guess work and no rules-of-thumb.
The computer model is applied for a particular weather data set, and I am finding that TMY is not the best. I will present on this at the ASES conference this summer.
------------------------------
M Keith Sharp
Emeritus Professor
Louisville KY
Original Message:
Sent: 03-06-2023 02:25 PM
From: william fitch
Subject: What are some technologies that you would like to see covered more in Solar Today?
Yes. What you are describing really is a super-insulated house with a modest level of PV, daylighting, passive solar and HP for backup heat. This allows for a good net positive output using a sub 10KW array, for a typical 2500sqft house, barring extremes like saunas, heated pools, no EV's, and sub 50 deg latitudes. Throw in EV's and you might need a 15 or 20 KW array.
I have geothermal, active solar hot air and liquid systems and gened 20.5 MWH last year and used all of it. Three EV's used up probably 9 to 10 MWH's that would have been over production.
Compare that to a leaky or low level insulation home less the direct solar energy for heat and daylight and you might have to add another 5-10 MWH's a year depending on allot of variables.
SO all that "stuff" can help. I just don't no if it can be faster as far as the "big" change over. New construction is the only way to deal with allot of this, and builders do NOT like to change. It messes up their profit margins, the change that is.
Its funny, or maybe not, all these conversations have been going on since the 70's and 80's when Superinsulation was the "hot new" kid on the block, along with all the data supporting it. And yet, here we are. Now its Passivhaus, same thing really, broad strokes. The main road block is the choice to take incremental debt over front end cash load. People would rather pay twice as much over time then 1/2 immediately. They want that feeling of disposable income even though for most it is an illusion, enslaving themselves to the banks forever. In the movie, "The International" there is a scene (I call it the sofa scene) that covers the floor blood red with the real truth about banking, and it is Soooooo well done. Link below:
https://www.youtube.com/watch?v=LFqx2sROwsE
This is one of my favorite movies that lays things out......
Best line in the movie, "Sometimes a man can meet his destiny on the road he took to avoid it".
https://www.youtube.com/watch?v=oPJ8fHUa7OU
All that said, more RE is better, where ever you can get it.
------------------------------
william fitch
Owner
www.WeAreSolar.com
Original Message:
Sent: 03-03-2023 09:19 AM
From: M Keith Sharp
Subject: What are some technologies that you would like to see covered more in Solar Today?
Solar buildings!
Why? Buildings have the most potential of all sectors for dramatic reductions in energy use and carbon emissions. They consume 71% of US electricity, as well as 25% of natural gas [EIA 2022]. Building operations, building materials and construction are responsible for 47% of total US carbon emissions, the highest among all sectors. Addressing buildings is, therefore, an essential component of the solution to the looming climate/energy crisis. Electrification of buildings and even net-zero buildings are insufficient, because conversion of the grid to all renewables is too slow. By 2050, 44% (compared to 60% in 2021) of electricity is predicted to still be produced by combusting fossil fuels [EIA 2022]. Because built floor area is expected to double by 2060 [Global ABC 2017], this means that fossil fuel combustion for buildings will increase compared to its current value. An intervention beyond current strategies is required to change this trajectory.
Ambient energy (sun, ambient air, ground and sky) offers that change. Over half of the energy used in homes is for heating and air conditioning (55% in 2015 [EIA 2018]). Water heating comprises 19%. Lighting, refrigeration, clothes drying and cooking, which are 10%, 7%, 5% and 1%, of the electrical demand, can also be met by ambient sources. Lighting (17%), ventilation (16%), cooling (15%) and heating (2%) are 50% of the demand in commercial buildings, and can use ambient energy. By maximizing locally harvested ambient energy, the electric grid necessary for serving the remainder of the load for buildings could be smaller in 2050 than it is today.
Topics on solar buildings include active and passive solar heating, passive cooling, daylighting, thermal storage (including phase change, sorption and seasonal), construction techniques, air-sealing and energy recovery, humidity control, real estate valuation, building codes and standards, high-performance windows and insulation, active control of solar gains and passive cooling, computer modeling, design tools and extreme meteorological year weather data.
ASES and Solar Today have a proud history on solar buildings. Because they are no less important now, it would be good to see this tradition continue.
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M Keith Sharp
Emeritus Professor
Louisville KY
Original Message:
Sent: 03-02-2023 08:42 PM
From: Joe Schiller
Subject: What are some technologies that you would like to see covered more in Solar Today?
Kat:
I am interested in learning more about technologies that facilitate integration of solar and wind onto utility grids. Many utilities claim that non-inertial generation technologies such as solar make grids unstable, but I know there are technological solutions to this. However, there are many facets to implementing these technologies. Some are purely technological, others are economic, and others are cultural. In other words, there is plenty of room for exploring these issues in Solar Today.
Joe Schiller
Sent from Mail for Windows
Original Message:
Sent: 3/1/2023 1:04:00 PM
From: Kat Friedrich
Subject: What are some technologies that you would like to see covered more in Solar Today?
Solar Today is looking into strengthening our technical content, including adding information about R&D. What are some technical subjects that you would like to see us cover? We cover the energy transition with a focus on solar power within the United States.
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Kat Friedrich
Editor in Chief
ASES
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