Author Topic: More panels!  (Read 29802 times)

LowGear

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Re: More panels!
« Reply #90 on: June 25, 2018, 09:50:49 PM »
Damn Readers Digest and all of the dead legs I've suffered because some pervert left them next to the toilet.

But on a slightly different note.

I had a revelation while pulling weeds this morning and it was inspired by one ajaffa1's recent posts.

I have become somewhat of a bore on anti petroleum and coal energy production.  I apologize.  This is my favorite forum and I will be getting back to basics from now on no matter how much I'm baited (see, I'm the victim).  Thanks for your time and energy.

Aloha
« Last Edit: June 25, 2018, 09:57:06 PM by LowGear »
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BruceM

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Re: More panels!
« Reply #91 on: June 26, 2018, 03:29:55 AM »
Windows can be big loss in an otherwise well insulated house, but how it affects the total heat or cooling bill depends on what percentage of loss is windows.  People get suckered into spending a fortune on double pane windows as a retrofit when their money might have been better spent elsewhere, like insulating shutters or curtains, and increasing other insulation. 

For winter heat loss, look at the total outside surface areas- walls and ceiling and exposed masonry/concrete slab edge. if you calculate the area of each type surface and it's temperature in degrees below room temperature, you will will have a good measure of the relative contribution of window vs wall vs door vs ceiling vs outer floor area vs inner floor area.  Then you can estimate how your proposed insulation will affect the total BTUs needed in that room.

For windows with solar gain in the winter, insulating shutters are the hands down winner unless you have too much gain.   On my previous home I made the mistake of way too much passive solar gain- all double pane glass on the south (northern hemisphere). The view was awesome and the daytime gain was so sauna-like that windows had to be open to keep it below 85F in the dead of the winter.  But the night time loss was so great that the rooms would be 58-60F in the morning.  That was very educational.  I had to add thermal shutters to all the windows and patio doors.  I later added reflective mirror film on the outside of all the south glass to cut down the gain, which was a huge help in the summer as well.

 For the thermal models, you have crank in all that data plus outside temperature, wind and soil temps and then you can play what-if's to see how it affects your BTU.  That's how I was able to figure out how to optimize my home insulation for my climate while on a low budget (plus 6 years of sweat equity). The biggest bang for my buck was the perimeter insulation; I had no idea that so much heat was lost through the outer floor in a slab home.  That's the reason so many in floor heat (slab) homes are so expensive to heat- heating mother earth is a loosing game.  The earth is NOT a good insulator at all, and even in our arid climate the one place that stays damp even in summer is under the slab and next to the footings.


You will certainly notice the cold convection draft from windows and solving that will help with comfort as well as some heating cost.  Just remember it's the total surface area x temperature drop below room temperature that makes your heating bill. 

For your situation only the parabolic trough solar hot water collectors would work as you must have high temperatures to use a radiator in your forced air system.  Which reminds me-  take a good look at your duct insulation; half your electric heat watts may be wafting out your gable vents and draping additional fiberglass bats over the duct work might be well worthwhile. 

« Last Edit: June 26, 2018, 03:34:50 AM by BruceM »

BruceM

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Re: More panels!
« Reply #92 on: June 26, 2018, 06:40:41 AM »
Where exposed, slab edges are a big thermal problem both winter and summer unless you have a thick carpet pad and carpet as insulation.  (I think carpets are toxic indoor air polluters myself.)  Check the floor temps from the wall inward to see for yourself and use the temperature change below room temperature time area to figure the contribution to room losses.

A strip of 1.5" (EPS-R9) beveled edge foam board with some metal trim made to cover it and tuck under the siding, in a suitable color works well. Ideally it should go down to the frost level. (Not far for you.)  Most siding companies that do metal work can bend prefinished steel trim pieces to your dimensions. They usually have a wide selection in colors. There are some composite and cement board products used to cover foam perimeter insulation but that's less likely to be useful as a retrofit.

If you look at some plans online for foundations for the latest low energy designs in Germany you will see massive use (10s of thousands of dollars worth) of high density EPS foam around the foundation.  My climate is milder and frost line is only 16 inches so I was able to avoid the special molded foam products and roll my own simpler design.  For my new neighbor's home I had him increase the sub-slab 25 psi  EPS (blue board) to 3 inches for the outer 4 feet, plus the same 4 inches between slab edge and stem wall, and 1" outside the stem wall down to the footing.  The edge insulation is very cheap for it's performance.  The sub slab insulation adds up fast because of the area but the savings in being able to greatly downsize the heating system pays for the foam even before the first fuel bill.  We can hide the 4" of foam between slab and stem wall by having the 12" wall- the inside framing (non load bearing steel studs) sits on the heated/cooled slab.  The top block of the stem wall is only 6 inch to allow for an extra strip of 2" foam only 1 block high.  The second 2" foam goes all the way down to the footing. 

You may be able to find a good free thermal model to play with...it's tedious and time consuming but very educational.



ajaffa1

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Re: More panels!
« Reply #93 on: June 26, 2018, 01:09:25 PM »
Hi Guys, I spent a lot of time in the French/Swiss Alps building in summer, skiing in winter. The issue of cold bridging is horrendous when you have temperatures as low as minus forty centigrade at night. Any property without sufficient insulation will be almost uninhabitable and have every water pipe burst. Cold bridges will very quickly identify themselves due to the condensation/ice that forms and destroys the interior finishes.

Remarkably they build primarily in concrete which has next to no insulating properties. The trick is to build the shell in concrete and then completely clad it in 150 mm of urethane foam with special attention to window and door reveals. Add triple glazing and you are in with a chance of staying warm. I wonder what they are going to do after the Grenfell tower disaster in London, can`t imagine they will strip all this flammable insulation and replace it. Skiers beware!

I did see the aftermath of a fire in one block of apartments in Val D`isere, wasn`t much left. Thankfully it happened in summer when the building was pretty much vacant.

Bob


BruceM

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Re: More panels!
« Reply #94 on: June 26, 2018, 03:05:09 PM »
There is much to be learned from designs for extreme climates; I borrowed from Canadian double framed wall designs.

An issue that I don't think is being considered enough is indoor air quality.  Air to Air heat exhangers will help dilute indoor pollution but reducing the pollution in the first place seems wise.  I used aluminum foil laminated to the mudded drywall and sealed at electrical boxes and base of wall to block wall and insulation materials from outgassing to the home interior.  The foil is finished with tile (we now use magnesium oxide cement as adhesive) and clay putty/paint - no exposed foil. The foil doubles as part of radio/microwave shielding and my house was measured at -110dB (voltage) or -55dBm (decibles of milliwatts of power) worth of shielding at 2.4 GHz.  I didn't need that much shielding for my rural location (until a cell tower goes up nearby) but wanted so see what was practical to achieve for whole house shielding without having the house look too odd and on a pretty tight budget.  I used heavy duty screen frames with 50 tpi stainless steel mesh as over-screens to shield the window openings. It was quite a design and construction effort. 

ajaffa1

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Re: More panels!
« Reply #95 on: June 26, 2018, 11:16:56 PM »
Hi Bruce, double walling is a very good way to reduce cold bridging all modern UK homes us it. Interestingly they used to sell drywall backed with aluminium foil as a vapor barrier, don`t know if it`s still available.

Bob

BruceM

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Re: More panels!
« Reply #96 on: June 26, 2018, 11:49:17 PM »
The foil backed drywall is still sold in the US, but at a very high price. It is of no value as a vapor barrier unless you gasket all the seams, and still it will leak since it's penetrated by so many screws and is so thin it's full of micro-perforations.  We changed to laminating 1 mil (0.001 inch thick) foil on the mudded drywall and it's a vast improvement- thick enough to stop nasty insulation odors, no perforations, way cheaper than the foil backed drywall and a much better result.
 







LowGear

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Re: More panels!
« Reply #97 on: June 29, 2018, 01:52:11 AM »
Quote
Alas, Casey,  the loss through the window glass alone, R2 really does have half the heat transfer as R1. The R scale really is linear.

Hmmmmm.  So I'm standing on a barren mountain and it's cold.  I have a glass greenhouse put around me and it's warmer.  I have a second glass greenhouse put around the first greenhouse and it's not as cold.  A third and .......  That first greenhouse just has to have the greatest impact.  Of course I'm mixing R values with infiltration however the difference between greenhouse 1 and greenhouse 2 are not as great as that first greenhouse.  The marginal equivalence between greenhouse 1 to 2 and 19 to 20 just can't get past the little gray cells in my head.

I'm thinking that the 1 inch pine greenhouse might be a bit different than the single pane glass one?

Thinking is bothersome.  Give me a Readers Digest article in the throne position and you have me by the little gray cells for life.

My other educations have led me to believe that infiltration is the bad boy of heat loss especially in older houses.  I'm surprised that humidity hasn't come into the conversation yet.
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ajaffa1

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Re: More panels!
« Reply #98 on: July 17, 2018, 12:38:43 AM »
So much for global warming. Frosty here too, below zero in Grafton is unheard of, hope it isn`t going to kill my mango tree.

Have you thought about fitting wooden shutters to the windows? Painted up they can add a lot of character to a home and deter burglars.

BruceM

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Re: More panels!
« Reply #99 on: July 17, 2018, 02:40:41 AM »
Inspired by Glort's home power work, I've been working on my ultra low EMI inverter again in the last 10 days, both hardware and software mods. I did my first load of laundry with it about 5 days ago. By a minor miracle my MS related brain fog has lifted a bit lately.  I'm fine tuning at this point, set up with modified toroidal transformers for 230VAC (true RMS via shifting the width of the 5 step waveform), and am adding circuitry for remote control. The two H-bridges that do all the heavy lifting, power wise, only draw 5ma of 12VDC when "off" (open circuit outputs) so I am NOT adding an additional solid state relay for remote inverter control. Instead I'm just having the processor shut down the H-bridges and turn it's own power off. Running it and the H-bridges total 55ma of 12V. 

I just did an efficiency test with my two Antek transformers late this afternoon and am pretty pleased-  94% at 1000 watts of load.   Idle (no) load is only 14.1 watts (0.10 amps at 141V).  Efficiency could be improved by going with custom transformers but only a few percent.  I modified them with 64 added turns to the secondary windings.  There's presently a 1.6% loss in DC filtering to keep my 120VDC clean.  I have only 1 mv of 240 Hz ripple on the 120VDC supply at 1000 watts of load. I made a 14 MH choke/reactor for the first stage of the filter, using a 400W toroidal transformer core I gapped and wound with 118 turns of 12 awg. It works well but I lose 1.5V right there at 1000 watts of load, should have used 3 strands of 14 awg.

It's been a very educational project, and I'm looking forward to calling it quits on improvements and just putting it into service up in my battery bank shed.  But while I have it still on the bench it's hard to resist fiddling with it.


BruceM

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Re: More panels!
« Reply #100 on: July 18, 2018, 04:39:48 PM »
My clever design to remotely control the inverter without adding a solid state hv relay resulted in some failed power mosfets and ics.  My memory is so poor I forgot the high side of the h-bridges is powered by swinging capacitor which is only charged when it's mating low side mosfet is on, so the h-bridges can't be used as solid state switches.  i now remember figuring that out later last year, but it slipped. 

Back to the drawing board. 

 

BruceM

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Re: More panels!
« Reply #101 on: July 19, 2018, 04:04:16 AM »
Nothing like the school of the real world, that's for sure.  Studied the problem and have come up with a few solutions but will mull it over a bit more.  If I change the H-bridge circuitry polarity so that with the inputs off, the low side transistors are on (shorting the transformer primary), with a corresponding inverse change in in the data table that defines the sequence of events in shaping the 5 step sine, then I COULD use the H-bridges as solid state switches.  When the processor is "off", the low side transistors being ON will keep the high side power topped up, and the high side transistors will stay safely off.

I just hate to make a mess of my custom H-bridge PCBs-  they are clean- no cuts and jumps, and very dense since I had to squeeze it all onto the small "experimenters board" size.  I also like that it is presently all "positive logic" in software and hardware (1 is on or higher voltage) and the high side or low side circuitry is identical. It helps me keep things straight in my addled brain.

It's been fun luxuriating in my huge to me increase in PV power.  I've been using my shop heat lamps for load testing - while the sun shines I can turn on 1500 watts and still (just) keep the batteries in float charge.  Someday I'll turn that into water chilling for house cooling...




 


BruceM

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Re: More panels!
« Reply #102 on: July 19, 2018, 04:05:55 PM »
"Modern Architecture" has been largely about sweeping expanses of glass...which is a killer for thermal performance.
There is an architect in New Mexico who preaches and writes about "eco" housing, now using straw bales but previously cast pumice-crete.  Some wealthy friends (wife with severe MCS) paid her over $40K for house plans I reviewed.  I was flabbergasted. Her plans had pumice-crete poured right down to the footings with no barrier to stop damp earth moisture and bacteria wicking up into the house wall, and no vapor barrier on the inside to stop moisture migration into the pourous cement wall in winter (it was to be raw plaster finish).  Damp portland cement walls are notorious for causing health problems and became infamous for that in Germany when so much low income housing was built after WWII with cast concrete walls. It was known as "the concrete sickness". The interior walls were all pumice crete cast over thickened slab...so good luck ever making any changes for wiring or plumbing.  The slab details showed it was NOT insulated- yet the home was in floor heat(!).  Oh, and as drawn, for a small home of about 1400 SF, she had 4 levels of roof, and no means of support for the roof over the center of the L shaped home.  The open L courtyard faced the prevailing SW wind in an area notorious for high winds.

I don't think most people realize that architecture is ART SCHOOL.  Very few rise above that and actually try to learn something.

My plan for the house cooling is to run a 1.5 hp water chiller in the in floor heat system water.  Once I finish the inverter project I'll have to research details of propane and mineral oil for refrigerant.  It's the devil in the details bit that is a concern, I'm on a low budget.  It's got to be cheap since I will rarely use it; it's only during wildfires and/or controlled burns that I can't cool the house adequately by just opening the windows at night. 















broncodriver99

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Re: More panels!
« Reply #103 on: July 19, 2018, 07:52:33 PM »
My plan for the house cooling is to run a 1.5 hp water chiller in the in floor heat system water.  Once I finish the inverter project I'll have to research details of propane and mineral oil for refrigerant.  It's the devil in the details bit that is a concern, I'm on a low budget.  It's got to be cheap since I will rarely use it; it's only during wildfires and/or controlled burns that I can't cool the house adequately by just opening the windows at night.

I can see 2 possible issues with that that you may want to do a little research on before committing.

First is the latency you will have with all of the thermal mass of the concrete. It would likely take a day or two or maybe more depending on your refrigerating capacity to cool the slab enough that you would realize any cooling benefit to the room and then it would be marginal. Remember, heat rises so any cooling benefit would likely be to the soil unless the slab is extremely well insulated. I can offer some real world info as far as the amount of horsepower it takes from my day job if you are interested.

Second, would be the temperature necessary to have any benefit and you would likely need airflow across the slab in order for it to absorb the heat. IIRC you are in an arid environment so humidity may not be an issue but if at any time your slab drops below dew point you are going to be making condensate all over your floor. It happens here on the East Coast all of the time.

If you are trying to minimize electrical usage(ie no fans/blowers) you could also look into a gravity refrigeration system. They require a lot of suspended piping and don't have a lot of thermal storage capacity unless you bank ice or have a large reserve of chilled water. The best time to bank ice is at night though when there is no solar available.

BruceM

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Re: More panels!
« Reply #104 on: July 19, 2018, 09:09:07 PM »
Glort,
Using the Lister to run an auto compressor is out-  it's 400 far away, over a hill.  Running the Lister as generator for a compressor is fine, since this is so rarely used.  But it would be neat if I could use my inverter to handle it during the day...I could use it more often which seems to be the trend for the SW US.

Window AC units direct would be the obvious solution but I can't use them, for ELF magnetic fields, sound, air quality and wrecking the shielding that my home provides with it's fine stainless mesh screens over all the windows.


Bronco,

Your comments were thoughtful and right on the mark for a typical home in a typical setting. 

Most conventional in floor heat systems in a concrete slab home are so badly designed that yes, for heating or cooling mostly you are trying to change the temperature of the earth and outdoors.  My home is only 1100SF and is superinsulated, including the 5.5" thick slab.  On a 100F day it gains 3-4 degrees.  The house air temperature is 2-3 degrees above the slab temperature.

In floor cooling has been well tested in concrete in floor heat systems in a study paid for by New Mexico state.  They were using night sky radiation via unglazed solar water panels on flat roofs to chill the water.  Their goal was to just remove heat load from the building overnight...and this it did quite well and for very low cost.

After reading the reports from NM, at elevations similar to my own, I did some testing on night sky radiation/evaporation cooling via water trickled down steel roofing measuring delta temperature, temperature, humidity, wind and flow rate.  It is viable but if there is no wind, and no clouds it requires a minimum collector area of 1000 SF for my 1100 SF home.  That's a lot of corrogated steel roofing.  If there are clouds, there is no night sky cooling so it is not a certain thing.   Using the shop roof for night sky cooling would be possible but is hell on the roof since the well water is pretty high mineral content. I'd rather put the steel on racks just above the ground, which also removes head so a 20 watt DC pump would easily manage the water flow at the minimal lift needed.   

My neighbor and I did some experimenting with running his 65F well water through his 900SF shop floor a few years ago.  It worked so well when the slab temperature was 10 degrees and more above water temperature that when he was living in the shop during home construction he ran it every afternoon to cool off the shop. His shop and slab is also insulated but not nearly as good as his and my homes.  Based on the flow rate and temperature rise, I did calculate that the typical BTU capacity of a 1.5 HP compressor was just adequate for my house.  65F water isn't really cold enough for a desired 72F...not enough delta T; you really want 55F water.  Running it for 4 hrs during the middle of the (summer) day when I have excess PV capacity should suffice to lower my house temperature the necessary 3-4 degrees.  My need would mostly be for June wildfires, where there is no shortage of PV power in the day.  My battery system isn't designed for carrying 1200 watt loads at night.

I did monitor indoor temperature and humidity here during the intended cooling period of June through July and there is plenty of margin so no chance of sweating floors in my climate here.  The floor mass is being cooled only a few degrees in a day... it will well above the dew point.  As you noted, it is not possible to use in floor cooling in a more humid climate because of the floor condensation, and besides, dehumidification is much desired.

My concerns about window AC units converted to propane are- can they be used on fuel grade propane, and how do I insure the right type and amount of oil...and concerns about purging the original oil. I have 10 gallons of white mineral oil so of course that is an appealing lubricant.