Posted By ICFHybrid on 16 Mar 2012 02:13 AM

So, in your mind problems listed in help forums are representative of an entire industry.

It's not just in my mind. The problems "listed" here definitely come from the geothermal industry.

For ICF to deliberately overlook the word "representative" is either a vain attempt to support a lost argument, or indicates preschool level comprehension skills.

Posted By joe.ami on 16 Mar 2012 02:28 AM
Don't bother asking again geome, the artful dodger will simply misrepresent the question though the answer is self evident.

I completely agree Joe.  ICFHybrid misrepresents geothermal facts as well (as indicated by this discussion.)  Not the first time. 

ICFHybrid misrepresents geothermal facts as well (as indicated by this discussion.) Not the first time.

I'm sorry; that just isn't true.

I have made very few "representations" about geothermal to begin with. You'd have to show us the ones that are outright misrepresentations.

Posted By Looby on 15 Mar 2012 07:05 PM

Posted By Dana1 on 15 Mar 2012 04:55 PM
Graph it on Weatherspark, if you like.

Roger. Wilco.

The mean January temp in Wayne PA is about 33F...
the mean January temp in Port Orchard is about 39F.
BFD.

One of docjenser's primary (and as yet unanswered) arguments was the
issue of freezing HX coils in air-source systems at low ambient temps.

The Weatherspark graphs clearly demonstrate that freezing conditions are
the norm in the Philly 'burbs throughout Dec, Jan, Feb -- but rather unusual
around Puget Sound, even on the coldest day of winter.

...so, yes, it's quite a pronounced BFD,

Looby

Being below freezing drops the outdoor dew point, resulting in fewer defrost cycles, and thus a lower impact on average COP due to defrost cycles.  In rainy-foggy Port Orchard the amount of frost accumulation will be significantly higher than in Wayne.  Plot the wintertime dew points in Weatherspark, if you like:  Port Orchard's dew point hangs around 34-35s, whereas Wayne's average winter dew point is ~22F.  That's a 10-12 degree lower dew point, but only less than a 5 degree (3 months of winter) outdoor temp.  Port Orchard's losses to defrost are on the order 2x that of Wayne's, but it has a slightly higher mid-winter air temp to level the playing field, at least for the coldest 4-6 weeks.

The primary factor is still air temp, and over ~200 days of heating season the is less than a half degree average.  And the a coldest-month difference of only ~6F,  so again, it truly is no Big Farhrenheit Difference, no matter how you prefer to pronounce it.  It may be even less than that, , or even colder in Puget Sound on average, depending on which Puget Sound weather history and dataset you prefer to use. Olympia is closer to Port Orchard than Seattle, so using Olympia as the climate comparison, Olympia has 500 more heating degree days than Philly (more HDD than Harrisburg, but distributed over a slightly longer heating season):

http://www.climate-zone.com/climate...n/olympia/

http://www.climate-zone.com/cli...ladelphia/

http://www.climate-zone.com/climate...arrisburg/

Better mini-splits running mid-speed at 30F will be running a net COP of over 3. The same mini-splits will run COPs above 2.5 at full speed at 20F or at mid- speed at 15F.  In Worcester County MA the January mean temps are ~22-25F, design temps are in mid to low single digits, where mini-splits are dogging along at a COP of 1.5, yet the seasonal average COP here runs ~2.5.  At 40F temps they're all running over 3.5. 

Since it it has ~10 degrees higher outside design temps, and ~10 degree average 3 months of winter temp, compared to Worcester, it's hard to see how you  won't average a COP of least 3.0 in Wayne PA.  But in places with design temps in negative double-digits and average winter temps below 15, sure, it's going to be tough to get much efficiency out of a mini-split, or be able to provide design-day heat in anything but a superinsulated house.  Code min homes in Fargo or International Falls are definitely not candidates, but coastal mid-Atlantic climates are pretty favorable.

The largest climate difference between SE PA and Puget Sound is summertime dew points and sensible cooling design temps. SE PA has design temps of ~90F to Puget Sound's ~80F, and 40 grains @ 50% RH latent load to Puget Sound's NEGATIVE latent load (you would have to ADD moisture to the air in summer to bring it up to 50% RH in Port Orchard!)   Philly has about 1000CDD of sensible cooling, to ~100CDD for more Puget Sound locations, so cooling efficiency will be far bigger consideration in Wayne than Port Orchard.  But again, it's not SO hot there that there's a huge efficiency advantage for geo vs. ductless,  the way there might be in the gulf coast states.

Posted By ICFHybrid on 16 Mar 2012 09:42 AM

ICFHybrid misrepresents geothermal facts as well (as indicated by this discussion.) Not the first time.

I'm sorry; that just isn't true.

I have made very few "representations" about geothermal to begin with. You'd have to show us the ones that are outright misrepresentations.

ICFHybrid, be sorry all you want, but my statement stands.  In this thread alone, do you recall the phrase "troublesome ground loops" that you believe (or just try to get others to believe) are commonplace?  This is an outright misrepresentation (in case you weren't paying attention.)

Posted By docjenser on 16 Mar 2012 01:56 AM


One of the points is that both locations might have the same total heating degree days for the whole year, however, Philly spikes more down to more extreme temps way below freezing, while the Puget sound is influenced much more by the pacific ocean and keeps the temp relatively stable, usually slightly above freezing. Again, what works well in the Puget sound with above freezing temps does not have to work in regions with more extreme temperature dips.

The 99th percentile heating design temp for Philly is +15F,

Design temp for Bellingham is +21F

For Olympia it's +23F.

I've been in Seattle & Tacoma when it hit 0F- so? 

We're talking a sub-10F difference on 99th percentile heating season temperatue data on moving 25 year binned hourly dataset.

I'm not buying the notion about how comparatively "stable" the winter temps are in that climate- I've spent decades there.  That kind of thinking about the record cold excursions unworthy of a heating design professional- the kind of thinking that leads to heating systems capable of supporting the 99.999 th percentile temperature condition.  Use the empirical data- the winter average determines the average COP,  sizing any heating system to provide more than 50% over the of the design heat load the 99th percentile heat load is an abuse, but at 25-50% oversizing a mini-split will average about a half-COP higher than if sized dead-on the money matching the house heat load at design temp, and WOULD BE CAPABLE of delivering the full load at 0F, if 25% oversized at Wayne's design temperature of 15F.  Resistance heating or a wood stove as auxilliary heat for record-breaking cold snaps is fine.

In Worcester MA  where I currently live the design temp is +5F, but I've seen it as low as -18F, yet people heat with ductless air-source goods here too.

There's nothing magic about 32F.

Posted By Dana1 on 16 Mar 2012 12:12 PM

Posted By docjenser on 16 Mar 2012 01:56 AM


One of the points is that both locations might have the same total heating degree days for the whole year, however, Philly spikes more down to more extreme temps way below freezing, while the Puget sound is influenced much more by the pacific ocean and keeps the temp relatively stable, usually slightly above freezing. Again, what works well in the Puget sound with above freezing temps does not have to work in regions with more extreme temperature dips.

The 99th percentile heating design temp for Philly is +15F,

Design temp for Bellingham is +21F

For Olympia it's +23F.

I've been in Seattle & Tacoma when it hit 0F- so? 

We're talking a sub-10F difference on 99th percentile heating season temperatue data on moving 25 year binned hourly dataset.

I'm not buying the notion about how comparatively "stable" the winter temps are in that climate- I've spent decades there.  That kind of thinking about the record cold excursions unworthy of a heating design professional- the kind of thinking that leads to heating systems capable of supporting the 99.999 th percentile temperature condition.  Use the empirical data- the winter average determines the average COP,  sizing any heating system to provide more than 50% over the of the design heat load the 99th percentile heat load is an abuse, but at 25-50% oversizing a mini-split will average about a half-COP higher than if sized dead-on the money matching the house heat load at design temp, and WOULD BE CAPABLE of delivering the full load at 0F, if 25% oversized at Wayne's design temperature of 15F.  Resistance heating or a wood stove as auxilliary heat for record-breaking cold snaps is fine.

In Worcester MA  where I currently live the design temp is +5F, but I've seen it as low as -18F, yet people heat with ductless air-source goods here too.

There's nothing magic about 32F.

Did I say a single word about oversizing? My concern was the failure due to ice build up, as reported in some of the links above, at lower temperatures, for example in the 0F to 15F range. BTW, what makes you think that 25-50% oversizing will give you half a COP more efficiency? Plus it is hard to imagine to see the look of my customers when I would have to tell them that they need to fire up the wood stove when it gets cold.

Or let me revise that to say, "There's nothing magic about 32F AIR temperature."  relative to the efficiency being a few degrees above or below 32F, or the defrost cycles.

The coil can only frost up if the COIL (not the air) is below 32F, and that happens at fairly modest heating loads, even with 40-50F air. The critical aspect that determines whether it will actually accumulate frost and the rate of frost build-up is how far below the air's DEW POINT the coil is, and the moisture content of the air:

To pull heat out of 38F foggy-dew Puget Sound air the coil has to be well below freezing- a few 10s of degrees below that nearly-saturated ~35F dew point air- call it 10F, for a 25F delta-T between the coil and the dew point.

In a drier SE PA climate with 33F air @ 22F dew point,  the coil needs to about ~6-7F colder too pull heat out for the slightly higher heat load of the cooler temp, so the coil may run about 3F, or a 19F delta-T between the coil and the dew point. Which is a smaller delta between coil and dew point.

Now take a look at the right hand edge of the psychrometric chart:

http://www.handsdownsoftware.com/APC-Chart.PDF

Air with a dew point of 34-35F contains about 38 grains of water per pound.  

Air with a 22F dew point contains about 21 grains of water per pound.

That's a mere 55% of the moisture content of 34F dew point air.

So with the slightly cooler air running though the coil it's both a lower delta-T between dew point and coil temp,  but also only ~55% of the water available to rime-up the coil.  This is why in Wayne PA it have about half the amount of defrost losses than in the slightly warmer but much more humid air of Port Orchard WA.

In sub- 0F operation there are almost no defrost cycles even when the coil is also below the (now quite cool) dew-point. There' just not enough water in that air to load up, and defrost cycles are few & far between.  The COP sucks there, but it's due to the high delta-T between the coil and the interior, not losses to defrost cycles.

But but of course we all know that air source heat pumps can't work in the mid-Atlantic states because it might snow outside, or get down to below freezing...

...despite thousands (or even tens of thousands world-wide) of existence proofs to the contrary.

In regards to COP increases with modest oversizing, see figure 5, page 10 of this document.  

At 17F at mid speed it hits COP about 0.5 higher than running fully flat out. 

At 35F at low speed it hits a COP about 0.5 higher than running at mid-speed

In the sample location under discussion the  outside design temp is 15F, the average mid-winter temp about 33F.

If  25%-50% oversized for the heat load at 15F it will run between low and mid-speed at 33F, and between mid and high speed at the 15F design temp.

If sized exactly for meeting the heat load at 15F it'll only pull a COP of 2.1 at design temp rather than 2.5+, and at the average 33F winter temp would only pull 3.5 compared to 4+.  If oversizing a half-ton is even possible, it's worth it.

If you grossly oversized it (which is hard to do, if you have anything but a super-insulated house) you'd get a COP of nearly 5 at 35F by only running at low speed, but between the wind chill of the higher cfm  blowers on the interior heads  at min-flow and the short-cycling, would make it less comfortable.  These are fully modulating systems, but the turndown ratio isn't infinite.   When oversizing a ductless for higher efficiency 50% would be about the limit of what makes sense from a comfort/effciciency point of view. 

In my mother's Port Orchard house we went with ~20% over manual-J (which is probably 30% over reality) and anticipate beating an average COP of 3.0 handily, but not necessarily beating 4. 

My uncle on the northeast side of Whidbey Island  (smack in the middle of Puget Sound, design temp in the low 20s) went a bit more than 50% over Manual J and hitting over 3.5, maybe even over 4 for an average.  In his case mounting the interior head on the tall great-room wall keeps the wind-chill well bounded, and allows it to convection heat the sleeping quarters on the second floor rather than go with a multi-split.

I haven't instrumented either of these, but in my uncle's case there's sufficient heating history on the place to work backwards on it to hit a close approximation. This is my mother's first heating season on her place, and the prior system has the issue of ducts (insulated and tight but) outside of conditioned space.  Even without subsidy from the utility, the combined cost of BOTH of those systems adds up to less than 1-ton of geo, and we're talking non-super insulated (not even current code-min) houses, and design & average temps only modestly higher than in Wayne PA.

[edited to add]

The icing up/snow burial issue isn't a defrost issue, it's a poor installation location issue. These are easily forseen and avoided problems (no rocket-science required) for folks who live in snow country.  The picture docjenser linked to in Oak Park IL wasn't a 15F and frosting up problem,  it was a 30F and raining ice-storm problem, combined with an installation of the unit out in the open sans protection of eave overhangs or sufficient clearance above grade to avoid drifting snow. (Probably installed by an air-conditioning company less-experienced with heating with heat pumps in that climate, or maybe even a DIY.)  Around here they're usually either wall-mounted under eaves or have a mini-shed over them if installed at grade.  If you read the text of their work-around, (scroll down)  they merely had to run it in cooling mode for awhile to get it to shed the ice.  In a better thought out installation this would not have been necessary.

If the requirement is that you can't be STUPID and install these things in heating dominated climates, methinks that applies across the board (and maybe triple for geo installers, where the costs of design &  installation errors are higher.)

The fireupthewoodstove face would be less contorted than the holdingyourbillfor25grand face methinks.

Posted By toddm on 16 Mar 2012 02:35 PM
The fireupthewoodstove face would be less contorted than the holdingyourbillfor25grand face methinks.

WIMP!!

Posted By Dana1 on 16 Mar 2012 12:12 PM

Design temp for Bellingham is +21F

Not so artful, Mr. Dodger. Bellingham ain't on Puget Sound.
It's well north of the sound, and several degrees colder.


"An awkward, unscientific lie is often as ineffectual as the truth."
-- Mark Twain

The climate of Bellingham Bay is the same climate as that of the east end of Straits of Juan de Fuca or Puget Sound from a design temp point of view- it's all the same tidal-slosh  and nearly the same wind currents- your distinction is a pretty shallow academic one of geographical naming rather than a true distinction in local climate.  Bellingham gets more rain than Port Orchard though, since it's not in the rain shadow of the Olympics as often.  There are other local climates that are more interesting though eg. Sequim, in the rain shadow of Hurricane Ridge gets but a tiny fraction of the rainfall of other places less than 20 miles away.)  But the design temp in Sequim isn't very different from rainy Port Townsend just down the road.

Design temp in Bellingham, (north of Puget Sound)= 21F

Mid-winter average temp in Bellingham is also 39F, just like Port Orchard.

Design temp in Olympia (on the far southern end of Puget Sound) = 23F

Are we to call a 2F delta in design temp, and a 0F delta in average winter temp "several degrees" now?

Reads more like a difference without a distinction to me, but have it your way, eh?  I was rong!

You have to go as far west as Port Angeles (on the Strait, design temp +27F ) to reap much benefit of being closer to the Pacific, where it's less obstructed by the mountain ranges.  Seattle hardly counts, due to the urban heat-island effects of Seattle/King-county,  but it's design temps are in the mid-20s, not the high 20s, as is Tacoma at +24.

Now that this horse has been kicked thoroughly to death and then some, check out discussion & graphs starting under "Heating and Cooling", starting on page 19 (.pdf pagination), in this document. 

The analysis for this upstate NY location was that the crossover point where a ducted air source heat pump has a higher carbon footprint than heating with gas is +12.7F, and the crossover point where it's CHEAPER than heating with natural gas is +15F. 

A ductless heat pump will have a curve aproximately 1 full COP higher than the ducted heat pump modeled in figure 2-2, which shifts the carbon and heating cost crossover temps to the left by about 10F (COP drops to 1.5 somewhere around  the 0F to +5F rather than at +10F to +15F, as charted).

Utility rates and electricity carbon-footprints will vary, between NY  & PA locations, but if your design temp is +15F (not your average), heating with a mini-split in PA is surely going to be signficantly cheaper than heating with gas, and with an average winter temp over 30F heating costs are in the geo range.

But of COURSE it doesn't work in a real NY climate it's just some dumb paper model done to appease NYSERDA nerds, right!?!  Let's hope they told those guys who built the Up-Hill House about that, it's gets pretty cold & snowy up there in Cambridge NY.  (Which is probably why they bracket mounted the mini-split well off the ground, protected under the overhang of the eaves, like some other folk shoulda.)

Posted By Dana1 on 16 Mar 2012 06:53 PM
Now that this horse has been kicked thoroughly to death

You can kick a horse to death, but you can't bring the mountain to Mohammad.

You also can't make anyone who has wintered in both the Philly and Seattle
areas agree that those climates are even close to equivalent. Just superimpose
the Weatherspark.com annual average temperature graphs -- or read their
"executive summaries" of the two regions:

"Bremerton, Washington has a mediterranean climate ...."

"Blue Bell, Pennsylvania has a humid continental climate ..."


"Statistics is the art of never having to say you're wrong."
-- C.J.Bradfield

Bellingham ain't on Puget Sound.

Ha Ha. I'm from there and I'm afraid we all think it is.

Dana1, as usual, has the correct handle on the weather here.

do you recall the phrase "troublesome ground loops" that you believe (or just try to get others to believe) are commonplace?

The phrase refers to the ground loops that are a constant source of discussion in this very forum.

It is probably also much easier and faster to install air source than ground source and more doable from a DIY standpoint. Given the right floor plan I can see air source as being much more feasible than ground source and the cost difference is huge, definitely in the air source's favor.

Not every system will work in every situation, but with air source becoming more efficient, it definitely should be considered close to the top of the list for heating and cooling systems.

-Rosalinda

Posted By ICFHybrid on 16 Mar 2012 08:13 PM

Posted By Looby on 16 Mar 2012 03:03 PM
Bellingham ain't on Puget Sound.

Ha Ha. I'm from there and I'm afraid we all think it is.

The USGS defines Puget Sound as all the waters south of three entrances — the main entrance at
Admiralty Inlet being a line between Point Wilson, on the Olympic Peninsula, and Point Partridge,
on Whidbey Island; a second entrance at Deception Pass being a line from West Point, on Whidbey
Island, to Deception Island and Rosario Head, on Fidalgo Island; and a third entrance at the south
end of the Swinomish Channel, which connects Skagit Bay and Padilla Bay. Under this definition,
Puget Sound includes the waters of Hood Canal, Admiralty Inlet, Possession Sound, Saratoga
Passage, and others. It does not include Bellingham Bay, Padilla Bay, the waters of the
San Juan Islands or anything farther north. -- http://en.wikipedia.org/wiki/Puget_Sound

...ICFHybrid: always in error, never in doubt.

Looby

It appears that your brand of scholarship didn't get far enough to consider the following paragraphs in your own Wikipedia source. Maybe we should just let NOAA and the USGS fight it out, huh?

How remarkably dishonest that little demonstration of yours was. Never mind that you are sitting off somewhere on the Internet trying to tell someone a thousand miles away how to consider the region they live in.

Another definition, given by NOAA, subdivides Puget Sound into five basins or regions. Four of these correspond to areas within the USGS definition, but the fifth one, called "Northern Puget Sound" includes a large additional region. It is defined as bounded to the north by the international boundary with Canada, and to the west by a line running north from the mouth of the Sekiu River on the Olympic Peninsula. Under this definition significant parts of the Strait of Juan de Fuca and the Strait of Georgia are included in Puget Sound, with the international boundary marking an abrupt and hydrologically arbitrary limit.

According to Arthur Kruckeberg, the term "Puget Sound" is sometimes used for waters north of Admiralty Inlet and Deception Pass, especially for areas along the north coast of Washington and the San Juan Islands, essentially equivalent to NOAA's "Northern Puget Sound" subdivision described above. Kruckeberg uses the term "Puget Sound and adjacent waters".

...Sometimes the terms "Puget Sound" and "Puget Sound and adjacent waters" are used for not only Puget Sound proper but also for waters to the north, such as Bellingham Bay and the San Juan Islands region.

Posted By ICFHybrid on 17 Mar 2012 01:06 AM
Sometimes the terms "Puget Sound" and "Puget Sound and adjacent waters" are used for
not only Puget Sound proper but also for waters to the north, such as Bellingham Bay
and the San Juan Islands region.

Yeah, whatever. Sometimes the term "Philly 'burbs" includes Wilkes-Barre, Scranton, ...

...and Sault Ste. Marie.

Looby