Posted By joe.ami on 24 Mar 2012 09:26 AM 
I will add alert to your last post as a Yea toward ASHP forum- I think it's time.

Just did the same.  Possibly a high efficiency ASHP forum since this site is "Green Building Talk."

Posted By ICFHybrid on 24 Mar 2012 10:07 AM
As Dana points out, the existence of separate sections wouldn't stop him from weighing in on
issues that come up in either section and I'm sure that goes for a number of others, me included.

According to that "logic," the dozen or so greenbuildingtalk.com forums could
be greatly improved by merging them all into a single, undifferentiated blob.

But why stop there? Let's do away with pesky URLs and unify the internet!
One web page should be enough ...or maybe two: english and not_english.

...and while we're at it, let's Reunite Gondwanaland!

Looby

When i first suggested ashp forum i mentioned that among the benefits we would hopefully attract the pros who prefer the technology. There is little to attract them here now. Ofall my posts i can sqfely say less than 100 are in the other forums here as i am not expert in those technologies.
Curiously the folks who have a lot to say on multiple forums likely arent in the business of any. That does not mean theyve nothing to contribute, but sometimes a pros perspective or expertise is handy

It looks like climatemaster is going variable speed.It can turn down to 33% capacity Trilogy 40 has an EER of 40 with full on demand DHW capabilities.
I think I might send the first one to Dana

According to that "logic," the dozen or so greenbuildingtalk.com forums could
be greatly improved by merging them all into a single, undifferentiated blob.

No, that's not at all logical. Heat pumps aren't the same as windows and doors or even lighting, to name just a few examples.

That does not mean theyve nothing to contribute, but sometimes a pros perspective or expertise is handy

It sure is. I agree with you there.

Just as a homeowner's perspective is useful as well as prospective customers and even people who actually have an education in engineering, for example.

I like to hear just about all of 'em.

Posted By geodude on 24 Mar 2012 01:24 PM
It looks like climatemaster is going variable speed.It can turn down to 33% capacity Trilogy 40 has an EER of 40 with full on demand DHW capabilities...

That sounds interesting.  Here is a link I found via google:

http://hvacrdistributionbusiness.co...rier-0319/

Posted By ICFHybrid on 24 Mar 2012 02:16 PM

Just as a homeowner's perspective is useful as well as prospective customers and even people who actually have an education in engineering, for example.

That would depend entirely on the engineer.  Lots of quack doctors, lawyers, etc., out there.  A person with an education in engineering is no exception. 

Posted By joe.ami on 24 Mar 2012 09:26 AM
Dana I agree with insulation and load reduction. You and Curt have been large part of my education in that regard. So was a problem in the field when reliable software didn't seem so reliable any more (blower door test revealed major softspots in insulation.....).
I will add alert to your last post as a Yea toward ASHP forum- I think it's time.

For those who don't know....Daiken curiously makes water source products and owns McQuay so I'm gonna guess they don't think air source is the only answer.

Does ANYBODY think air source is the "only answer"?  I sure don't, not even in climates where split-system air source efficiency can rival that of geo. 

Sprawling houses with lots of doored-off areas and zones with dramatically differing heat loss/gain charactieristics could require a real Medusa of refrigerant lines & muli-split heads with no real advantage (cost or otherwise.)  Modestly sized homes with relatively open floor plans (or high-R homes) are more conducive to mini-splits than some others.

I DO think high-efficiency air source deserves consideration for any ~2500' home in US climate zones 5 & under, especially when the heat load at design condition is under 3 tons (or can be made that low for less than the price difference between split air-source at 2-3 tons vs. geo at 3+ tons.)  While some may view me as a mini-split zealot, (a joe.ami probably sees correctly) I'm really more about high-efficiency building envelopes than high efficiency mechanical systems.  Code-min is bad joke in most places, and the cost (even in retrofits) of cutting down to sub-30KBTU/hr design heat loads can be surprisingly cost effective in may situations compared to the cost of even low tonnage geo.  If the floor plan & aesthetics are conducive to split air-source, any difference in efficiency between mini-splits & geo at the 1.5-3 ton range will practically never have a financial rationale in zones 5 or lower.  (Spending the cost difference on photovoltaics may even have a better financial basis in some cases.)   But it's not a solution for every situation, not even close.

Clearly geo isn't a one-size-fits all "only answer" solution either ('ceptin' in the minds of sales-zealots, some installers, and true-believers. :-) ), but there are many situations where it's the most-acceptable way to go. Geo can work in any climate, so the question is really where the crossover lies in cost-effectiveness & efficiency. The title of this thread is still "air source versus ground source in heat dominated climate".

It's my take that even in much of US zone 6 air source isn't a show-stopper, even if it loses big ground to geo on efficiency there, and may even flat-line  to a COP of 1 at design-temp.  It probably doesn't make financial sense for homes on the gas-grid in those colder climates, but if it can meet even the 80-90% heat load it'll have fairly good economics relative to oil/propane/resistance-electric heating in most markets, (misplaced anxieties of defrost-disaster-in-waiting nothwithstanding.)   Ductless air-source is good for a COP of 2.5@ +15F these days, so in places with mid-winter averages in that range or higher it's not a disaster.   At mid-30s average winter temps (like Wayne PA and much of US zone 4) they take on geo-like average efficiency, and that's still very much a "heating dominated climate".

So sure, put be down for a "Yea" on making a high efficiency ASHP forum- it's definitely a different beast with different issues than geo, despite similarities of some of the system components.

Posted By Dana1 on 22 Mar 2012 11:14 AM
You admonish me to check the evidence before posting(which I generally DO), yet you're happy to make assertions that minisplits lose huge efficiency to use of resistance defrost heaters (a component that that doesn't actually exist in any mini-split that I'm aware of), then post a picture of an ice-storm encrusted compressor unit improperly installed in the open as evidence that the mini-split defrost somehow can't keep up or are somehow so problematic that they cannot or should not be used in heating dominated climates. More anecdotes: While traveling earlier this week I at a restaurant in a ski-tourism town (Stowe VT) that was heated and cooled by a 2-ton Fujitsu, properly installed with a small shed roof protecting it from heavy snowfalls. I stayed in a condo at ~1k' of altitude at a ski area (Smuggler's Notch VT) a few doors down from a ~750' condo heated with 2-head 20K Mitsubishi multi-split, (MXZ-2A 20NA), with the compressor politely protected from roof-avalanches & snowdrift by the back deck. (Other units in the building were heated with ~25-30K propane wall-furnaces, but that unit clearly was not, with no exhaust vents or regular/meter in evidence.) These are locations with negative double-digit design temps and annual snowfalls in excess of 200" . Apparently the news that you can't run these things without them icing up or getting clogged with snow or ice has yet to reach snow country.

I started this thread since I had seen my share of frozen up outside coils and customers depending on dual fuel systems because the ASHPs loosing not only their efficiency but also their capacity. We also have freezing rain a few times a year where I live. My "coldest" customer was at -10F this year (it was a warm year), last year it was -26F. And there is no way to protect the heatpump from the 2-3 feet of lake effect snow blowing things around.
That fact that you saw one on a house without an exhaust pipe or a chimney does not mean they work well and efficient under extreme cold weather conditions. I am a big fan of designing an efficient house, and going the extra mile on building performance. But there is limit on what I would like this to be. And after having invested that much in a house, the last thing I would like to have in there is a mini split.
I like where the technology has gone, and most of it will swap over to the GSHPs, but it will never get to the reliability and efficiency of a heat pump taking it from the stable ground, and not being exposed to extreme weather conditions.

it will never get to the reliability and efficiency of a heat pump taking it from the stable ground, and not being exposed to extreme weather conditions.

I think what is being discussed here is the fact that there are situations where ASHPs can and do beat geo, particularly where you take care to include a full definition of "reliability" and "efficiency".

You do realize that not every "heating dominated" climate has the same type of extreme weather you have there in Buffalo, right? There is no question that there are places where geo will be the first choice, but there are other areas where ASHPs will be indicated, like here in the Pacific Northwest.

It's the envelope folks. Fix the envelope. Doesn't matter where you live, if you are heating the outdoors expect discomfort and high expense. A good envelope doesnt care about 10-15f, it hardly sees it.

Lol. I read the first two pages, then it started to repeat.

"your mild climate is milder than my mild climate"

"ground loops are NOT problemmatic"

"inverter driven air source doesn't work everywhere"

"size to the heating load"

What a bunch of Huey. Hopefully most here understand why setback doesn't work, as long as that is abandoned, ground and air source work equally well when properly designed.

In my area (much colder than PA) air source gives natural gas a run for the money to below ZERO. Good geo guys go to 8 ft and MONITOR water temps, while the cheap guys go to 4 knowing most homeowners dont track or analyze consumption, they simply pay the bills.

In Mass they build 2400 ft homes with one mini split PER FLOOR. I have split and mini splits that see single digits working great.

GREENSPEED inverter driven split beats the pants off poorly installed geo, and if you aren't tracking water temperatures or energy consumption you don't know your system isn't inefficient.


Dana, I admire your efforts but at some point you might want to recognize you may be attempting to teach your depth of experience and subtleties of your knowledge to unwilling, possibly unsophisticated audience. People who have significant financial or emotional reasons to reject what you are attempting to convey are going to reject your truths.

Put another way, you can fix ignorance, we do it and have it done to us every day. Not sure you can fix prejudice or fix stupid. Key is differentiating and recognizing when to give up. I think you may be pounding your head against a brick wall.

Posted By ICFHybrid on 25 Mar 2012 08:52 AM

it will never get to the reliability and efficiency of a heat pump taking it from the stable ground, and not being exposed to extreme weather conditions.

I think what is being discussed here is the fact that there are situations where ASHPs can and do beat geo, particularly where you take care to include a full definition of "reliability" and "efficiency".

You do realize that not every "heating dominated" climate has the same type of extreme weather you have there in Buffalo, right? There is no question that there are places where geo will be the first choice, but there are other areas where ASHPs will be indicated, like here in the Pacific Northwest.

The fact that the ground loop is not exposed to any kind of weather risk, wether it is a snowstorm, freezing rain, debris flying around, you name it, is a conceptual advantage. The fact that the source temp can never get much below 30F is also a conceptual advantage. It does come at a price of higher upfront cost. No question in milder climates ASHPs might be a better and cheaper alternative. I am heating my pool with one.

Posted By Tedkidd on 25 Mar 2012 11:55 AM
It's the envelope folks. Fix the envelope. Doesn't matter where you live, if you are heating the outdoors expect discomfort and high expense. A good envelope doesnt care about 10-15f, it hardly sees it.

Lol. I read the first two pages, then it started to repeat.

"your mild climate is milder than my mild climate"

"ground loops are NOT problemmatic"

"inverter driven air source doesn't work everywhere"

"size to the heating load"

What a bunch of Huey. Hopefully most here understand why setback doesn't work, as long as that is abandoned, ground and air source work equally well when properly designed.

In my area (much colder than PA) air source gives natural gas a run for the money to below ZERO. Good geo guys go to 8 ft and MONITOR water temps, while the cheap guys go to 4 knowing most homeowners dont track or analyze consumption, they simply pay the bills.

In Mass they build 2400 ft homes with one mini split PER FLOOR. I have split and mini splits that see single digits working great.

GREENSPEED inverter driven split beats the pants off poorly installed geo, and if you aren't tracking water temperatures or energy consumption you don't know your system isn't inefficient.


Dana, I admire your efforts but at some point you might want to recognize you may be attempting to teach your depth of experience and subtleties of your knowledge to unwilling, possibly unsophisticated audience. People who have significant financial or emotional reasons to reject what you are attempting to convey are going to reject your truths.

Put another way, you can fix ignorance, we do it and have it done to us every day. Not sure you can fix prejudice or fix stupid. Key is differentiating and recognizing when to give up. I think you may be pounding your head against a brick wall.

Stressing that the envelope should be improved is repetitive. We all agree on that.
The same is true for tellings us that a well designed system will beat a poorly designed and installed one.
I appreciate controversy, I actually learn from it. While I disagree with some of the statements made in regards to ASHPs, I would never call others with a different point of view possible unsophisticated, financially bias, rejecting the truth, ignorant, prejudice or stupid. No bad for your first post, Kidd. You are off to a great start...

I second DJs remarks - first off, try to show some civility - we value it here more than at some other sites.

Secondly, though I'm not a big fan of setback, it has been studied here by some of our veterans with very highly instrumented systems and been shown to work, that is, save some energy, despite the usual concerns about electric strip use during recovery. My intuition suggests that staying more often in stage one vs recovering using stage 2 is more efficient but even that was disproven, if memory serves...

As laudable as is improving the envelope, the system selected has nothing to do with the envelope. Whether 3 tons is needed to condition a super tight 5000 SF home or a horribly loose 1200 SF old farmhouse does NOT impact the question of what system type should be selected, whether that be geo, conventional split, inverter split or mini split. Each has unique costs and efficiencies depending on ambient air and ground conditions.

"Lol. I read the first two pages, then it started to repeat....."
You accuse "some" of ignorance while at the same time you seem to indicate you didn't read the entire content.

I think if you happened to fix your ignorance to the discussion at hand (by reading all of it) you would notice virtually every contributor has nodded towards envelope as the first concern.

If you spend more time on these forums you will find most of us agree more than disagree or at least respectfully disagree.

Then their are those who seem to be contrary or combative virtually all the time- at this point you sir would appear to be one of those.

BTW typical depth in Lower Pen Michigan happens to be 5-6' for horizontal loops.
Real pros will tell you that going to 8' vastly increases the digging requirements, so it is more economical to simply add mor length vs depth.
While their are those in Canada or approaching the artic circle that may require extra depth it is not generally true in the CONUS......so those who aren't ignorant to OSHA standards generally prefer 6' trenches.

Those who suggest loops can't work unless they are 8' are obviously ignorant to loop design as well.
Those who add words like stupid et al to their attack show a lack of manners as well as ignorance.

Good News! You can fix ignorance!

Posted By joe.ami on 26 Mar 2012 09:53 AM


Good News! You can fix ignorance!

 

Posted By Tedkidd on 25 Mar 2012 11:55 AM

Put another way, you can fix ignorance, we do it and have it done to us every day. Not sure you can fix prejudice or fix stupid. Key is differentiating and recognizing when to give up. I think you may be pounding your head against a brick wall.

I dunno about that.

docjenser's experience with iced-over dual-fuel air source heat pumps may be a well founded prejudice, but a shed-roof solution is a cheaper alternative than his favorite.

A shed-roof can fix a lot of "stupid" on poorly implemented air-source heat pumps, and seems to be the new-norm in my area.  Heat pump installers tend to come from an air-conditioning background, and leaving the thing out in precipitatation or roof drip lines is less of a problem during the COOLING season. But it seems to be a cheap & easy habit to break- the first 5AM call from the shivering customer would do it for most.

Let me ask another question here. Let's say I have a typical setting, old house with energy improvements, or a new house, 2500 - 3000 SQF one story home, with a typical design temp of 0F and a 40 - 50kbtu/h heat loss. So an air sourced heat pump has a COP of 1.5 or 2.0 at that temperature and minimal overall capacity. How am I gonna get 50,000 BTU/h into the house? Strip heat?

Posted By docjenser on 28 Mar 2012 06:01 PM
Let me ask another question here. Let's say I have a typical setting, old house with energy improvements, or a new house, 2500 - 3000 SQF one story home, with a typical design temp of 0F and a 40 - 50kbtu/h heat loss. So an air sourced heat pump has a COP of 1.5 or 2.0 at that temperature and minimal overall capacity. How am I gonna get 50,000 BTU/h into the house? Strip heat?

Spend the money on getting the heat load down to under 36K with air sealing & insulation retrofits, and drop in a 3 ton Mr. Slim (or a Daikin Altherma, if you love cozy toes and are willing to pay extra for it).  It's usually less money than 4+ ton geo,  even as retrofit (but particularly cheaper on new-construction. )

For example, I live in a ~2400' mostly one story bungalow (~350' upstairs) built in 1923, with 1500' of semi conditioned basement that stays above 65F all winter to boot. This hows has KNOWN gaps in the insulation, and standard triple-track storms over the original double hungs for windows. Design temp here is +5F, but it clearly gets colder. I'm constrained by radiation & water temps to a maximum output of about 42-44KBTU/hr, yet this place sailed through -8F temperatures without losing ground during a cold snap last year.   When I moved in the heat load was probably pushing 50K @ 0F, but it's well under that now after blowing cellulose into the walls that were easiest to get to, air sealing the place  a bit, and insulating on the foundation walls & band joist.  Based on fuel use and boiler efficiency analysis its somewhere in the mid-30s @ 0F now.

The Mitsubishi H2i series are specified for full rated output at -15C/+4F, and similar sized Fujitsus & Daikins will put out similarly, even without being fully specified there.  (Some models have -20C output specs to refer to.)  The H2i models deliver over 70% of rated spec at -25C/-13F.  It doesn't take much baseboard to cover the difference if the mini-split covers the load a design temp of 0F, and you have the cold-snap of the decade at -10F.

I COULD be heating with a mini-split, but it wouldn't be dramatically cheaper than the current gas-fired system- there's no incentive to move that direction. But it's just not that tough or expensive to pull the heat load down, even WAY down in most houses.  A 50K heat load @ 0F on a house that size is either a leaky wind tunnel or a shack- my place isn't anything like super-insulated (not even current code-min!). If my heat load was even 40K @ 0F it would mean they're slipping me some sort of super-therm gas in those pipes, since that would imply my heat loads greater than the source-fuel BTUs that actually support the loads.

But I suppose it's cheaper to just buy some electric baseboards instead of air sealing and insulation...

I'm sure there are some real antiques out there where it's too difficult, expensive or even impossible to get the heat loads that low with some appropriate retrofits, and those are clearly not going to be the best candidates for ductless air source heating.

And, places with design temps around 0F aren't likely to hit an annual average COP greater than 2.5 too.  With bigger heat loads and lower temps the present-value economics start tipping toward geo ever more quickly, when the design condition heat load is over 3 tons, and design temps are in negative digits F.