What's nice about sorta warm? and 90-degrees?

Climatemaster, I flipped dip switch to 95+, could do 100+

Hydro-Temp (AR) program holds a steady 106 to whatever ya like, and in all stages of 4ht and the cooling is selected by CFM and BOTH are set to stage by selecting
1/3 to 3 deg per hour data tracking/ at the rates that fit tight to loose homes, whatever the life-style calls for:

Think of tepid as only if you want it.  Think of 104+ at the registers, also if you want hot registers to the touch. hotter than a spa.

maybe go see dealer section, red board by Georgia Controls

the Green Viewers can ask: Do we get to select very warm to hot outputs in heating?

I see places for splits, as I have also placed registers per the late Heat-Pump (1980's ControlAire) distribution master: Paul doty.

Particular attention to space-conditioning with air-solar systems from set to operate from 80-110 in/at starting also lead to BETTER DISTRIBUTION.

One nice 75x35 kitchen-great-social and dining rm home is more than comfortable from corner to corner, retrofitted 80-year ols farm house, average cellulose 4" wet-packed walls, has all 2.1/4 x 12 registers and where using more runs to 7 per ton, it is like floor radiant heat, and without 400 fpmin throw , having floors warmed by 96-98 deg air temps - regulated.
Cooling is fine on a little higher air volume as well, all with high return air grilles and in 20" attic cellulose peaks the first day, 2 Compressor-tons r22 GT open well (rfg D=165-170 set penn control, low at 59-64 (like a 3-ton Air:Htp on an 80 or less ambient day, net comparison)
saving 25 % or more over 14 SEER Bryants sold throughout that era 1994-1997 handled the 1800 sq ft 2nd story completely. only 5-tons, great dehumidification, for just under 5000 sq ft , stone wall- some damp basement, ducts installed by others had a few returns taped.

Room over 2.1/2car gar and over laundry ~ 28x35, a lot of glass, was new, and the Bryant 2 ton 14 SEER there heated without backup to 3 above zero (valves were closed on gas HW small boiler loop air coil).

I think tepid is a fair choice of words. One of the conversations I have with every geo buyer is about air temperature.
Geo design is about less is more. Meaning you can get to 70* in your house with 90* air all day long but you will have to move a lot of CFM. 0* air blowing across your toes under the computer desk is aptly described as tepid.
Point is it is wasteful with geo or airsource or anything else to use 100+ degree air when 90 will do.
One can floor the car to the stop light or idle up to it, one uses more gas.
It is very important that geo sellers are candid on this point as one of negative comments about our systems is "it blows cold air".
I remember the same being said about 90+ furnaces when people switched from gravity units that had a 180* limit or 65% efficient units that went up to 150* etc.

Which brings me to my next point geo jon, you will need to back up your claim that your pet system is superior with 106* LAT. Any unit can produce 106* LAT, but only with a blower speed reduction. Is that the best way to deliver even heat?

Posted By geodude on 28 Apr 2012 05:18 PM

Posted By Dana1 on 28 Apr 2012 12:03 PM
The output air of geo tends to be on the very-tepid side

Nice Dana! It has been a while since you have referred to geo air as "tepid". You used to call geo air "tepid" in just about every post. I guess that is why you needed to say "very-tepid" this time.

Got data to support that thesis?  

I doubt I've used "tepid" in even 10% of my posts on the geo forum, (and fewer than 1% of my posts on this site overall.)  i cood b rong, offen am...

But in this case, so what if I'm right?  Geo air IS tepid so?  (And the distinction was that 80F air is very tepid compared to 100F air...)

It still heats the house- you just don't want to be sitting in the air-stream when running in the first-stage/low-temp/highest efficiency mode.  You also don't want to be sitting in the air-stream of a ductless if you don't have to either, but it's somewhat less of a comfort hit when you do.  That's not a random-feature- they give up a bit on efficiency to make that way, but they have to from a comfort point of view in order to be able to sell them into their Asian home market.  It's always better park the mini-split head somewhere that minimizes the wind-chill impact when there's a choice.

With any air-based heat delivery system, continuously-variable or multi-speed blowers can enhance comfort quite a bit by chillin' the wind chill when high cfm isn't absolutely needed. I prefer low-temp hydronic output to air for any of it, but that's a luxury that usually comes with a price tag, sometimes a very HEFTY price tag. Bumping up the temp by a few degrees air-delivered heating buys back quite a bit on creature comfort, but still isn't quite the same as cushy radiant floors/ceilings.

" You also don't want to be sitting in the air-stream of a ductless if you don't have to either, but it's somewhat less of a comfort hit when you do."
Had yur back a minute ago. Are yu suggesting ASHP has higher discharge air temp?

Posted By joe.ami on 01 May 2012 12:38 AM
" You also don't want to be sitting in the air-stream of a ductless if you don't have to either, but it's somewhat less of a comfort hit when you do."
Had yur back a minute ago. Are yu suggesting ASHP has higher discharge air temp?

Mini-splits, yes, ducted ASHP, not so much. 

Mini-split output is still tepid by scorched-air fossil furnace standards.  IIRC Mitsubishis run 'em backstopped at ~38C/100F, until it's -15C/4F outside by design ( I don't think it's user-adjustable.)  Fujitsu tends to run 'em at a ~30-40F delta-T  between incoming air and exit air, independent of compressor speed, for ~100-110F exit air in a 70F room.  Other manufacturers may have different control algorithms but keeping it at body temp or above whenever possible seems to be the theme.  This is decidedly higher temp than typical geo air.

Note the third-party tested supply temps in Tables 5 & 6 of this document. 

Your doc wouldn't open for me, so I don't know the parameters of your data.
Of course 100* is tepid when blowing across someone who's inner heat plant is 98.6. Geo and ducted heat pumps can deliver 100, or 110 as well depending on blower speed, EWT, EAT, outdoor ambient, etc. Not necessarily the goal though.
Higher air temp is indicitive of a short coming not an asset- less air moved or higher refrigerent pressures = higher temp. But again that is as much design control and application as inherent feature.

I'm not sure why it's not opening for you- clip the URL as text and try it: http://www.nrel.gov/docs/fy11osti/52175.pdf

The short notes on those tables:

The lowest temp the Fujitsu delivered with a 70F room was 97.3, at low compressor speed, high blower speed. Even at high blower speed in a 57F room it was still delivering 98.7F- there's an attempt to go no lower than human body temps. Under other conditions the exit air ranged as high as the low and mid 120s F.

The Mitsubishi tested varied between 100F & 132F in various modes. Under most test conditions the exit air was over 115F, and only dropped below 100F when the outdoor temp was under +4F.

The low operating temp highlights were:

At +2.8F outdoors/67.4F indoors it was delivering 119.7F air at low blower speed

At +2.8F outdoors/68.0F indoors it delivered 95.3F air at max blower speed.

At -9.7F outdoors/67.5 indoors it was delivering 88.1F air at max speed.

I understand the system-efficiency reasons why geo isn't normally run that high (and how the high exit temp reduces the efficiency of the ductless). I wasn't nature of advocating that feature or treating it as a superior feature (quite the contrary)- only noting as a fact that ductless air has a significantly higher exit temp than the vast majority of geo-air systems in normal operation, making sub-optimal placement of the ductless head less of a comfort issue than suboptimal placement of geo output. The reason for that design compromise on ductless temps is presumably for comfort in the tighter-than-north American-standard living quarters for which they were originally designed, but it's still better to avoid placing humans in draft if you can.

The exit air temps of Mitsubishi is higher than the (ducted, fossil-fired) hydro-air zone at my house. I could raise the water temp (if I wanted to take the hit in efficiency), but the Fujistu-like exit temps are still comfortable enough even when blowing directly on the feet of whomever is sitting in the kitchen eat-in nook. I would definitely not be setting up geo ducts that way. (The ducts are original to the house, nearly 90 years old. All I've done to them is seal & insulate them. It was converted to hydro-air maybe 16-17 years ago, originally with a gas-fired boiler ridiculously oversized for the load, which is why the air handler coild can still deliver more than design-day heat with 125F water. It's not how I would have designed it, starting from scratch, but with mods I've made it more efficient.)

Fair enough. Part of the mind set might be from the roots of mini splits which employed them as solutions to isolated space conditioning problems. They were not on the radar as a primary home heat source ten years ago in most areas.

Without being interested enough to research it myself, it would be interesting to know how much a minisplit could improve in efficiency if cooler LATs were designed in. There are so many factors such as greater CFM and Coil surface that improve efficiency (but are not as easily accomodated by anything defined as "mini"). This is the one that might be easily controlled.
As consumer education improves, they might benefit from a shift in philosophy or at least flexibility for the installer to choose between comfort and economy. Wouldn't an ASHP forum be nice to explore such things?

Indeed, a separate forum devoted to the state of the ASHP art would be useful, but I'm wonder how broad the discussion would be without push-back from the GSHP advocates to keep it honest?

sbeausol:  Other things that you might consider before committing to geo, depending on how dedicated you are to re-habbing the place, is to take advantage of deep-energy-retrofit subsidies available to National Grid customers in MA & RI (Nat'l Grid is your power provider in Essex):

https://www.powerofaction.com/der/

($42K of direct subsidy buys quite a bit of envelope efficiency upgrading, but this is not always going to be the most pleasant thing to do while living in it.  I've been advising on, but not contracted to, a project being done under that program in Worcester.)

If your house in Essex has it's own well rather than town water it's not out of the realm of possibility that if you get the heat load low enough with a deep energy retrofit you may not need to drill for geo, knocking a chunk off the upfront cost. (This is not a given, however.)

There are also 0%/7-year loans (up to $25K)  available from the state for financing GSHP and other high-efficiency heating systems, a program fully extended to electric heating customers in Essex:

http://www.masssave.com/residential...an-program

As of this date the loan subsidy is not yet extended to high-efficiency ASHP,  that may change, but I'm not holding my breath.  In an analysis of renewable thermal energy resource done for the MA-D.O.E. they cite ductless ASHP as still too new to the region, without sufficient information to determine the impact of peak grid loads.  The somewhat tepid (good word, eh? :-) )  utility conducted pilot study from a few years ago left something to be desired on sizing them for the loads, and were retrofit-only, partial solutions, not designed to be full-solutions (though with larger units they could be, for the 13kwh "typical" heating load of that thermal energy resource analysis. For a house that's been retrofit-tightened  to 10kw/3tons or less the prospects are even better.)  The pilot study attempted to determine the affects on peak-load based on the in-situ of  ~3-dozen undersized installations and still came with pretty reasonable, if preliminary numbers.   With more data on more and better monitored systems the subsidy picture for ductless air-source may change, but it'll be awhile before that data is in.  In similar climates in Scandinavia there has been a tsunami  of ASHP installations beginning about 5 years ago, swamping GSHP unit numbers of installations per year. There's already relevant data out there, but it's in mostly in Swedish & Japanese.

Posted By Dana1 on 01 May 2012 05:57 PM
Indeed, a separate forum devoted to the state of the ASHP art would be useful, but I'm wonder how broad the discussion would be without push-back from the GSHP advocates to keep it honest?

this reading of this group is really is easy enough! thank you .
I found your link openable if rt-click and 'properties' and copied the url and pasted
http://www.nrel.gov/docs/fy11osti/52175.pdf


 it's own well ... I have read on other posts some quality is an issue and on different sites, pumping and power to lift water and all those efficiencies is argued over.

There are also 0%/7-year loans (up to $25K)  available from the state for financing GSHP and other high-efficiency heating systems, a program fully extended to electric heating customers   Are there penalties iof you are using a back up of other than a 'on grid' source or fossil fuel (hwever small)?

 There's already relevant data out there, but it's in mostly in Swedish & Japanese.
[!]

at that doe mini split site   http://www.nrel.gov/docs/fy11osti/52175.pdf

i noticed there was a couple high points of that graph data that had an above- the straight line average. Also as well, instead of the air heat pump curves that are in print that are compared to other systems, there is on the mini split output graph a straight line from a 55 deg 22000 btu output to a 14000 (my estimate) where on other air heat pump graphs there is a real drop at +47 degrees F and at +17 the air heat pump graphs on other comparisons look lik a drop of a typical ni-cad battery. Other high efficieny graphs do not include points where there is a moment of water moisture freezing on the coils to a frost. 
About energy states of water freezing on heat exchangers for a short moment of a few minutes as it was discussed-
It was pointed out that water -liquid  as when it is getting to a freezing state, has heat energy moving away of 144 times that of just before a frozen condition, and just after the freezing change in a state of water, it is back to a 1:1 relationship.
The drops at 17 degrees on an Air heat pump were in part described about the icin build up and defrosting and refreezing conditions. Then in a graph  at that +17,  --curving  nearly straight downward, a 16000 btu represaentation is just about 11000 or 25% less at +7 degrees on the points of other curves (southern Wva, and Mid-southern KY, high Arkansas frequent winter lows for some comparison of heating considerations in mind).

Are there any curve types of graphics of mini splits completely to zero F ?

The pumping power & air handler power used by GSHP limits the real-world whole-system COP to around 3.5-3.7 in this region, but mini-splits in this climate will average a COP of around 2.5, so it's a significant boost in efficiency to go with GSHP. The financial question becomes whether the net-present-value of the power savings from the higher efficiency is more than the difference in up front cost in a reasonably short time-frame. On a lifecycle basis GSHP usually (but not always) comes out ahead. But if you don't have to drill another well it almost certainly would.

There is no penalty on the 0% loans for using backup for high efficiency heat pumps- IIRC code REQUIRES back up for heat pump systems in MA. I would imagine that the loan would require that the system be able to meet 100% of the load at the outside design temp though, rather than just an auxilliary (even if primary) source of heat.

Frost/de-frost cycles on mini-splits occur at air temps well above +17F- there's nothing magic about that number. If you're talking about the straighline trend curve in figure 3, p.8 (p16 of .pdf pagination), and figure 4, try to imagine the error-bars around each measurement- the implied precision of the single-dot representing the single test measurement simply isn't possible. But the trend line is still valid. The light-blue trend line published by Fujitsu the points likely represent a statistical average of many tests, since they have an ongoing engineering budget and have tested it more thoroughly. The line is also affected by the algorithms for adjusting the refrigerant volume- a simple line should not be expected.

Note that the data aquisition apparatus used in their tests didn't correctly measure the exit air temps of the outdoor unit, and the authors state on p.11:

"Since the actual outdoor coil inlet temperature was colder than intended, the reported experimental heating capacities would have been higher if actual inlet air temperature equaled the intended value. Thus, it is expected that the experimental heating capacities, at the temperatures plotted in Figure 3 and Figure 4, were higher than what is displayed."

Without an infinite budget for repeated test over multiple models the precision just isn't there- there's only so much you can infer from the graphs, but the general trends are clear.

What is clear that MANY people are heating their homes in first-world Europe & Asia in areas with design heating temps well below 17F. Mitsubishi publishes generic graphs of output capacity for their H2i series that goes all the way down to -13F/-25C, but they lack the detail provided in Ecotope's testing of those two models. No manufacturers that I'm aware of publish more than a few data points, and none describe their test procedures in any detail. But many publish output numbers at -20C/-4F, and almost all publish capacity numbers at -15C/+5F.

... which is convenient, since sbeausol's outside design temp is about -15C/+5F.

More interesting points, this board is pretty solid. Thanks everyone. Hoping to close next week which means I should have a thorough energy audit completed soon. I will be speaking to a local contractor as well so we will see what happens. One though I have is to do some the geo work myself. I will have 2.5 acres with plenty of room for horizontal loops so if I can install the loops that may save me money. We'll see what happens. I'm not ruling out the ductless minisplits either...

Whether horizontal loops cost less than drilling depends on a whole lot of factors. If it's swampy enough to be really close to the water table it can mean a lot less digging, but it can also mean you have to jump through a lot more hoops with the state as to whether you're disturbing wetlands, etc. I've seen one project in MA where the anticipated red-tape delays for permission to trench drove them to drill, and I'm sure that wasn't a unique case.

T's Dana- [means in long words: Thank you and Greetings Dana1]

  [edited a little for the cute one]

Sounds like
[common term for reading a writ of posted words]
those (already Dana's given) answers to (Dana's) identified problematic design may only be 2 or 3 communications
[-using today's telecommunication or facsimile ( a fax telecopier), and/or , but not necessarily- letters by that thing called electronic mail or Email, -or today one may have noticed is beyond a mail-pony-ride] away [term of 'away'  is herefound for in as a 'in-the-future' consideration].

Even before the footers or slab [-get installed, but even means here before they do get cement poured],  I (me) will always (every time designing) have
a spec [-ification, abreviated as seen in engineering]
for a well
[a borehole-well found for water, -all about a GeoThermal usage here in the thread of discussion(s) of with normalcy found in 99% of all other respondees above] 
if well water goes in
[sometimes a well is chosen for families to have water now days],
or a test dig
[that process pulling dirt away from the ground]  
the day the excavator
[ a person and machine for to do 'a dig' ]
arrives with a narrow bucket [for 'a dig'],
contract
[out lined phrase for 'making then a contract with the following:] 
"contingent upon unforseen" spelled out by points
[of unforseen un-expected (too, but by years of experience and closing about 8.1/2 out of every ten buyers and who understand outline writing, apparently, -and noted: sales closure ratio) -the seen things that sometimes are found in an installation of a system].
Our [of the writer responding]
Systems GT's
[that phrase refers to Systems of GeoTherma HVAC Htg Cooling and Hot Water (HW) noe being applied since the 1930's, and in homes since the 1960's...wqater:to:air and water:water w:w compressor-refrigeration pumps of refrigerants to deliver an exchange of thermal energy, etc. - can read up on other websites for one's education]
are quoted in wVa [WV] from name brand [some more popularly, but less efficiently known-named units] - [on large dealers'] painted  and multiple truck [type of even the higher-over-head reputable and great installing] dealers
@ [fiduciary referencing to expense in coin and dollars 'at'] last week:
[a] closed loop, 3"ton" as AHRI 'rated' unit , 
[ installed with]
horizontal 6ft dig hairpin layout
[view below as a bird's viewing from above (of those flying critters sometimes missed just when we are always looking down at everything, so)]/
[more descriptive 'hairpin' or ditch in the shape as known by doing installations and desiging-] horseshoe
sorta [slang, "oops" for sort-of-kinda-little-like-this-in-mind],
[also installed as with]
 4 pipes 2 3ft ditches,
[GT Unit that has only a little 6000 to 9000 btuh out put HW heating recovery of about 10 hours, but is acceptably over-technically]
desuperheating HW
@ [at]
 $ [dollars]
 under 17000 before
[sometimes utility companies have these very nice] rebates and
[following 'and' means in addition , here are, ]
credits [qualified buyers receive ] 
leaving 10,000 [that is dollars of total systemic installed first year costs (here-found as a 'cap' of a buyer's net expenses]
alowing for a
[celebration word use by those happy upward-thinking, practical and positive people attend as an event to enjoy, if one is not abusive and of so low of self esteem] party.
56-deg [ground temperatures below for the 'heat beneath the feet' (put on posters and cards since 1993) about soil]
[in the area of the City in Ohio]  Cincinnati-
[-to (as a range across noted System-GT-HVAC-HW-Reclaim installations through some United States of America -into- a state called Arkansas] AR
[about] soil temps [abrv: for 'TEMPERATURES found in the soil at 12 to 18  feet deep, in usaual winters, and damp clay (great
[for GT systems to absorb Ex (thermal energy transfer) by moving a colder-than-discussed-ground-temps refrigerant)
[not enough people are excited enough to have some answer that REALLY is [imbedded or not] clearly answering DANA1's very legitimate arguements and questions and comparisons.  So an Air Ht P thread is on two different postings for that as one reads this explanation [above edited] since below for only one other next to see was read before this was edited. ok, -

run spot run

me tarzan you jane

you talk pretty one day

Markets will differ by state & region, but I've yet to read, see, or hear of a 3 ton GSHP system of any type with a pre-subsidy installed cost less $20K locally. $25-30K, sure.

On a recently published survey document (buried somewhere in the MA state archives) the state average cost for GSHP was just shy of $9KUSD/ton, and in the same document they had ~$2.7K/ton was the average for ductless ASHP.

To be sure a ductless-ton isn't the same as a GSHP-ton when it's 15F outside, so those numbers aren't a good measure of the relative costs for systems that actually handle the mid-winter heat load. For some cold-weather ductless the +17F rated output is only about 0.6x the nominal tonnage rating (often taken at 47F) and even the rated numbers are dependent on the outdoor humidity (at any outdoor temp) which determines the fraction of time spent in defrost.

I'm about to take a whack at some ductless. Of course I can't have my first ductless project be something simple like a single evap system on a Florida room (glassed in screen porch to the rest of the US)

No - it has to be a 1x4 or 2x2 system feeding a pair of double wide mobile homes grafted together as a single home. The alternative is a complete duct rebuild in a crawl space, and my guys would prefer root canals over that, so we are gonna have a go if the owner bites, which he may well when he gets the crawl space reduct $ number.

My mom still lives in the home I grew up in in Manchester, MA. It has oil fired hot water base boards and no AC, other than window units. She spends $5k on oil, and I've thought about geo, but there is zero room for any kind of ductwork, so I wonder if ductless would be the way to go. Unfortunately it has 5 small bedrooms upstairs, necessitating a bunch of evaps, and natural gas runs just 200' away, although the NG line would have to somehow run through granite ledge, as would geo bores.

Nothing is easy...

Posted By engineer on 14 May 2012 09:46 PM

Nothing is easy...

Murphy was an optimist.

New High temp water - water for baseboard (waterfurnace 5 series), 150F supply temp, with outdoor reset. We are putting the first 2 systems in, started last week.

hi DJ;
R-22 138 degrees was important to a brewing company that wanted heat recovery with W:W and some openwell GT on 54 deg well water. The compressors are replaced at about 8 year intervals. The head pressres exceed by temperature: hot gas lines near 200 F, and 145 on the temp of the Hi gauge.
with having that in mind -
in/with under-floor radiant or heating domestice HW -
 and considering  "150" posted above,
with
R-410a and with temps not-thought usually, not -really wanted above 120 deg F -gauge (in any condition for longevity)yielding under 114-domHW, or radiant HW/HL  leaving the GT System at about 3.7 -to- 4+ gpm per heating side ton,

what's the expected resulting gauge pressure or temp at the high side/ say 4 or 5 gpm/t ?

(REM: Similarly readings over 120F h-gauge temp at setting a Hydro-Temp, of AR, programmed variable blower at 106 deg leaving air / about calc-est 320 cfm for est 31-deg rise E-Air of 75, high returns in about 72F comfort.)