Geothermal and Air Heat pump Temps for AIR COMFORT
Last Post 30 May 2012 12:25 PM by joe.ami. 124 Replies.
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jonrUser is Offline
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10 May 2012 08:34 AM
I agree with docjenser. While large radiators have some benefit (lower supply temps), high mass radiators cause overshoot, undershoot and interfere with setback. So likely to increase energy bills.
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10 May 2012 08:39 AM
Thank you Dj,
  'high mass'  to savings?

SAVINGS,  A)  &  B)  - Above what's missing is a two paragraph explanation. - these are for your answer- my curt format:) What I leave out is for others to be  asking about later,  -not misunderstanding your Q, I believe.

A)
the only high mass I was considering was slab in-floor radiant heating - thermal Energy flow Ex:to KWH's.
This was considered with an 88F LW to 82F EW returning from load 'reservoir'-heat-sink, and about a Refrigeration-HtP system called W:W mode GT, or even to include Raypak, Rheem, Aquacal, and POOL PAK, DEKTRON, DESERTAIRE...HW-heating to heat POOLS, too. [high mass HERE: large body of heating capacity, for comfort, -just being heated, and its heat-content allowed to warm people.]
All above was just about OBSERVED, metered  lower-KWH's allowing the GTHP Ex, thermal energy to move INTO that kind of (my thought intended) a 'high-mass' releasing Ex, kinetically from , say a concrete slab floor BUT -at a steady state- of Ex (floor not changing temperature at its surface) to be considered adequately heating a space.Also, technically, as with a mixing valve for bare slab floors in a 74-82F range of those EW settings in radiant to a basement rec or play room (or with a relatively thin floor pad).
-----
B)
 The savings is relative to  ~ 4gpm per HW ton for keeping W:W below an approx. 6F Tdiff
1- At a 104F LW from the W:W mode about 8% to 12% more KWH read 33.4 amps, as a mark here.
2- COMPARED to at only 88 to 92F LW, as the compressor discharge temperature and head pressure is lower, saving KWH's reading just 30.7 amps [edited  - for not having 2) PL55B&G kw, included,- the 28.9 is Forced-Air Heat mode, EA 2340cfm at 71F ]  at that same location and system and conditions switching from low mass flooring at joists to the slab zones.

3- not me, but only that fossil fuels nox gas emissions EPA report of 1993 comparing AirHtP SEER 14 and GTHP 26 SEER at then 34%-42%, "saving" , co-relatively, was accurate about rightly seeing TODAY  IQ Ver-Rfg savings of ~ 12% today's AHT-P (no duct losses)  over nGas and close to 22% SAVINGS by GTHP [ now add HW savings, and add a low recirculated HW for radiant designed-SAVINGS, etc., heat-recovery and within and among multi-zoned GTHP ] which supports a (here in town's forum) AiqHTP saving 22% to 27% over propane while GTiqHP is saving over40%, easily... (add the cooling savings of large loop or open well GTiqHP).
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10 May 2012 02:47 PM
Posted By knotET on 09 May 2012 09:51 PM
SO Dana thanks again:
if I am getting a 44% savings over condensing propane, with hi mass slab radiant or same type of forced air heating with GSHP multi staging, heating MODULATING blower keeping 92 or 96F outputs, what would you throw out as a % savings with mini's?
THere are no duct losses in the equation. Right statements can be accessed about ducting, but there are none in this event.


I recently ran the numbers for someone on an 80% efficiency propane wall furnace vs. a seasonal average 2.5 COP ductless using the 5-year average for MA propane & electricity pricing, and it was just shy of 60% cost savings. (Both propane and electricity are more expensive here than in OH.)  And that was assuming the propane wall furnace was providing ~10% of the heat (for backup during highest-humidty cold & peak lows.)

So with condensing propane assuming no duct losses that would be about 50% savings.

[edited to correct]

I was misremembering.  Looking over the analysis I submitted the savings at the 5 year average propane/electricity price with 90/10 division of ductless/propane heating came in at 46% savings.

It was at the 2011-2012 rates that it came in at 59% savings.

Total heat load where-is-as-is for this small place (about 800' of conditioned space) was still under 30KBTU/hr. I recommended some insulation & air sealing upgrades, and low-E storms over the remaining single-panes, of which there were two, and going with a 2-head 2.5 ton ductless which would be about a 90% solution. The balance & comfort would be better than the wall-furnace + space heater she's been living with, and the upgrade package (including the ductless) would pay off in under 6 years (simple) using the 5 year average, under 4 at last year's rates.  If the ductless performs at a COP better than 2.5 (which it should) it'll pay off sooner.  There is no GSHP solution that would fit her (retired, living pretty much on social security) budget, but the sub-$10 investment recommended will do much better than where her savings had been parked.
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10 May 2012 04:20 PM
Posted By docjenser on 09 May 2012 10:39 PM
Eh! You are absolutely right, ASHPs have made a big leap forward. And they are a great bang for the buck. But you get all excited about COP in the mid 2s to 3s, when we are at COPs in the mid 4s with GSHPs, including the 230 watts for the loopfield circulator averaged over the season. So a small load in a big room, sure, mini splits are a good alternative. But whole house heating still needs a distribution system. We have to keep the comfort in mind here too. Don't you want other rooms heated, too? Once you have to put one high wall unit in each room, the cost goes up. Sure inverter technology is a big leap forward, that is why they are getting introduced in GSHPs.

Your posts on the subject are very long, and very repetitive!

I've not seen credible 3rd party data to support the notion that the average full system GSHP seasonal COP is in excess of 4 yet, despite the onesie-twosies at the 2 sigma margins.  But if you can show me where to find third party survey data on instrumented & monitored systems such as the dozens of mini-splits in the NW Ductless project I'd be very interested to look at it. The smaller-scale studies I've seen to date all point to mid-3s as the system average. (Mid-3s, as in the measured average performance of a fleet of 1-3-ton mini-splits in Seattle.)

A 3-head 3 ton ductless can handle quite a lot of house floor plan configurations for under $10k.  And in a high-R home the room to-room temperature imbalances are pretty small compared to an R13+5 / U0.35 code-min type of house.  The notion that you would need anything like "...one high wall unit in each room..." to keep the place comfortable simply isn't well founded, even in a code-min house (but you may have to boost the temp a couple degrees in the rooms with heads to keep those without comfy at design temp in a code-min house.) High-R houses are far more amenable to point-source heating than typical construction, and the "...needs a distribution system..." argument fades pretty fast and pretty far- to the point where a well thought out HRV system can be used to further balance the temperatures (as is being done on a local deep energy retrofit I'm advising on.)

Marc Rosenbaum has been heating his moderately high-R house in MA with a single head 1-ton Fujitsu, and has been monitoring the temperature in different parts of the house. His too was a retrofit hack in a house not intentionally designed for  point source heating, and does not use the HRV design to balance the flows, but his room to room delta-Ts weren't terrible, and the cooler lows could have been better had he been willing to turn up the temp (something he is loathe to do, unlike the typical homeowner.)  His house does not have PassiveHouse type R-values (not even close) but as-operated it's pretty much net-zero, with 5-6KW of PV on the roof and an energy-stingy lifestyle of the occupants. But they're not freezing their butts off in one room and roasting in another.  The mini-split cost less than the nearly-new Buderus boiler he hauled out shortly after moving in.

The excitement isn't COPs in the 2s & 3s per-se it's the prospect higher comfort of the higher-R envelope  at  similar upfront cost (and operating cost) of the GSHP-only solution for achieving the same operating cost.  A COP of 5 would be pretty exciting, but not so much if the system cost was $150K.  At $9K/ton for a better class GSHP running a system-COP of 4 won't always make up for the cost difference between COP-3 ductless at $2.7K/ton during it's lifecycle, even if you add ton more ductless for low-temp capacity.

At the warmer edge of climate zone 4 don't be so sure that GSHP installations would always beat a better class ductless on raw efficiency either.  At mid-compressor speed they're all above 4.0 at 45F outdoor temps, and at low speed they're even higher.  To have sufficient capacity to handle the load at a design temp of say, 25F (where it's running with a COP of 3 even at high speed) it'll be just idling along at at winter average temps of 45F, with a COP in excess of 4. In the NW Ductless monitoring the measured average COP in the Willamette region (a middle-temp part of zone 4) was in the 3s. (See table 33.) Design temp for Eugene OR is +26, Portland is +24 but the Puget Sound cluster has a comparable or cooler design temps and averaged in the mid 3s. Raise the temp 5-6F on the high slope part of the curve and it make a half COP difference.  Oversized by 25% at design temp and that too makes about a half-COP difference.  The vast majority of the units tested in the NW Ductless project were not intended as whole solutions, and as such were probably running slightly higher average compressor speeds for lower average efficiency.  These were for the most part retrofit-hacks into sub-code-min houses, not whole-solutions to well designed higher-efficiency building envelopes.


The varible refrigerant volume ground source technology is also pretty exciting stuff, but the total bang/buck of the whole house, not just the mechanical systems is more interesting to me than any "gee-whiz" mechanicals, and when the mechanicals are expensive, it pays to do the math on the balance point between higher efficiency building envelope vs. higher efficiency mechanical systems.  Moderately high-R is pretty cheap, when designed in from the start.
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10 May 2012 10:53 PM
Posted By Dana1 on 10 May 2012 04:20 PM
Posted By docjenser on 09 May 2012 10:39 PM
Eh! You are absolutely right, ASHPs have made a big leap forward. And they are a great bang for the buck. But you get all excited about COP in the mid 2s to 3s, when we are at COPs in the mid 4s with GSHPs,... Sure inverter technology is a big leap forward, that is why they are getting introduced in GSHPs.

[ knowing a little of the author of this thread tries to be accurate ] Dj states: Your posts on the subject are ...  repetitive! [ do you also mean DANA1? It is not clear to this author ]

DANA1 stated to Dj:
a)
I've not seen credible 3rd party data to support the notion that the average full system GSHP seasonal COP is in excess of 4 ----

b)
----one high wall unit in each room..."
to keep the place comfortable simply isn't well founded,

c)
willing to turn up the temp ----
---
The excitement isn't COPs in the 2s & 3s per-se it's the prospect higher comfort of the higher-R envelope  at  similar upfront cost (and operating cost) of the GSHP-only----
At the warmer edge of climate zone 4 don't be so sure that GSHP installations would always beat a better class ductless on raw efficiency either.

d)
The var-refg//---[as to] Moderately high-R is pretty cheap, when designed in from the start.

Dana
only annual 4.1 held by TETCO from 1979, having 5-t  60k HX on 43k compressor (like a mini- 4.1/2 "ton" for today's comparrisons) it was an early stage  - among multiple units running from thanksgiving to easter , non-stop. This had a near 7-real ton air coil and at the old 1/2 hp blower cap-start-cap-run hi eff GE, then moving 1650+ cfm, head pressures under 205 r22. The ONLY 410a at over-blown 500's cfm/ 10,000 btuh's usable net heat output, with head pressures below 300  and suction pressures (38-40 deg loops) above 110, are constantly nearly always over 4.0 cp's. The annual FUE -GT Ex at cp's of nearing a 4+ mark can easily be found with 100% domestic HW production in larger families of 5+ with PRIORITY-HW / annually-cycling, -respectively.
a)
AGREED ( by more of a GT nut that anyone will know for a while ) . Discussion from me did only point to, w/ little DeSuperheaters, of annually 3.4 cp's (very conservatively, though, for 2012 eStar GT-HP's). Tier 4eStar GT-   will FORCE all to either use 55% over-sized water coils on 35% over-sized air coils with minimum 2-staging systems and all that about the now selling: GTiq, as well as Aiq's. IQ by WF "due in JUNE" I was told today by a largest dealer. Hydro-Temp of AR already sells it. W:W and Priority full condensing in GT-HVAC are both going to have very little need of "buffer" tanks: iq4U !
b)
Djensen: Please keep asking; and at a point by line, with ANY commentary (always). We DO need your input regardless of some fringe commentary, politely-ment -an opinion of mine, although among MANY members that I see "long" and "repetitive" b/c of NEW THREADS for NEW VIEWERS allowing such a 'right' to welcome dozen's of thinkers to any thread... So you can CONTINUE reiterating, too, for any new thread, please:)
Dana1=
agreed again with that
  b)
When there are those who bragged of 50 MPG in a vw -as they really were a researching DIY monster-  (Dave W. , I knew in 1980...)by shutting off the engine, coasting, in a stick... - well  then any central heat source of a 10 deg warmer room at 75 in a space, to 67 in a closed door bedroom works for them. Them's are many more than I can imagines (all global humans inclusive).
c)
From of about all I have run into Dana1,
- there's a big divide between your shifting excitement of yours to imply "isn't cp's" to "...is...envelope", I have reason to be simple minded about.   I will argue at every post: Cp's are more than just one 'branch' off the trunk of the "envelope-" tree  and reach to those roots of greeni-things.  Fluid dynamics  of Ex, among the physics of Ex, thrills  most people I know that are the buyers-closed.    - This experience in 35 years of face-face seems true whether they can commmunicate it well, or can't (-or I don't.) Only highly positive responses are found about sharing just some of a 70% to 76% of sustainable ground/solar Ex discussion; or AHPiq's getting to just over 60% of that sustainable Ex, -maybe. COP explanation is met with wide acceptance. So I cannot concur a CP as discussed is being an "isn't" to a "what is" b/c of the abounding interesting positive responses. I have found CP-branches are full of many 'swings' that people enjoy riding ... Very many - right next to you in that swing.
d)
Doing 80% retrofitting- and from those "starts" = always in agreement with you there.

z)
Dana1 on another thread of a Mr miller, 1700 sq ft oil 04/12, , I believe in that kind of 425 gal of oil Sep-Mar 2012, very USUAL N-OH winter of -5 below (not Cincinnati +3 above to many -0's I lived in 19 years...in Z-Cinti) but like that even in at the boarder to wVa, those 0-deg towns in to below zero winters all seem to need more relative comparison of a more like 750-900 gal of oil in a usual winter to be expressed as ~ more of 40-48,000 btuh's .

Before the r-envelope fixes, 44,000-48,000 as the 'starting' argument. This would barely result in a 32-to-34Mbtuh design in these 7-8-12 degree balance points; and again, after practical fixes on a tighter budget as indicated. The smallest GTiq I can discuss is "size 3.0" comparing to Mini's on a 55-degree to 50-degree day Ex output. At 47F the ministarts falling off to about 15% less at 7-to-8 degrees long running cycles and GTiq is 45% higher COP, there and then.
A sales oddity is a "size 4.5" GTiq is only 600 more and a "size 5.5" only 450 more to a buyer, by just the Unitary component of the cabinetted  equipment alone. So 450-700 "gal-oil/yr-htg homes just fitting for a  "3.0" GTiq.

IN a real 55,000-45,000 load at -5 to 5 above zero load, r-envelope fixed... HERE I FIND: Pricing 5 mini zones off a 4 ton -iq appears to be for a retrofit @ $ 16,000 installed with 2 year service agreement and 5 yr parts and labor (pro-rata). < 400 Ut'y Co- rebates >...vs... $ 25,500. for a  "size 4.5" GTiq that IS a 1-winter ROI on the difference, making 100% HW, 3 zoning inclusive, and can have a little $ 175. HX coil for some Radiant or Pool spin-off. GTiq net book cost @ only $ 18,000 or 4500/ton WITH HW instant heater and tank and insulated lines and ,,,and,,, + nearly 2 1/2 times the dollars saved now in 10-12 years/ of the 30-yr longevity, and easily way more realestate value in 5 years ( at least 4 degrees above 'tepid' = fixed temp-modulating blower-sensing ) NOW.

~~~~~~~~~~~~~~~~
Aiq-HP thread is NEXT ! :)
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12 May 2012 01:15 AM
Posted By Dana1 on 10 May 2012 04:20 PM
I've not seen credible 3rd party data to support the notion that the average full system GSHP seasonal COP is in excess of 4 yet, despite the onesie-twosies at the 2 sigma margins.  But if you can show me where to find third party survey data on instrumented & monitored systems such as the dozens of mini-splits in the NW Ductless project I'd be very interested to look at it. The smaller-scale studies I've seen to date all point to mid-3s as the system average.


http://www.builditsolar.com/Projects/SpaceHeating/InField%20PerformanceTestingofGSHP_updated%2011_11_2010.pdf

You are right, good published studies are lacking, the one above is quite bad with very inefficient systems and lots of variances, which make me question the data. We see average total system COP in the mid 4s with 3 ton dual stage W-A, with an average heating season EWT of 38F. We have 15 Welserver online, and should summarize and publish the data.
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12 May 2012 01:49 AM
Posted By knotET on 10 May 2012 08:39 AM
Thank you Dj,
  'high mass'  to savings?

SAVINGS,  A)  &  B)  - Above what's missing is a two paragraph explanation. - these are for your answer- my curt format:) What I leave out is for others to be  asking about later,  -not misunderstanding your Q, I believe.

A)
the only high mass I was considering was slab in-floor radiant heating - thermal Energy flow Ex:to KWH's.
This was considered with an 88F LW to 82F EW returning from load 'reservoir'-heat-sink, and about a Refrigeration-HtP system called W:W mode GT, or even to include Raypak, Rheem, Aquacal, and POOL PAK, DEKTRON, DESERTAIRE...HW-heating to heat POOLS, too. [high mass HERE: large body of heating capacity, for comfort, -just being heated, and its heat-content allowed to warm people.]
All above was just about OBSERVED, metered  lower-KWH's allowing the GTHP Ex, thermal energy to move INTO that kind of (my thought intended) a 'high-mass' releasing Ex, kinetically from , say a concrete slab floor BUT -at a steady state- of Ex (floor not changing temperature at its surface) to be considered adequately heating a space.Also, technically, as with a mixing valve for bare slab floors in a 74-82F range of those EW settings in radiant to a basement rec or play room (or with a relatively thin floor pad).
-----
B)
 The savings is relative to  ~ 4gpm per HW ton for keeping W:W below an approx. 6F Tdiff
1- At a 104F LW from the W:W mode about 8% to 12% more KWH read 33.4 amps, as a mark here.
2- COMPARED to at only 88 to 92F LW, as the compressor discharge temperature and head pressure is lower, saving KWH's reading just 30.7 amps [edited  - for not having 2) PL55B&G kw, included,- the 28.9 is Forced-Air Heat mode, EA 2340cfm at 71F ]  at that same location and system and conditions switching from low mass flooring at joists to the slab zones.

3- not me, but only that fossil fuels nox gas emissions EPA report of 1993 comparing AirHtP SEER 14 and GTHP 26 SEER at then 34%-42%, "saving" , co-relatively, was accurate about rightly seeing TODAY  IQ Ver-Rfg savings of ~ 12% today's AHT-P (no duct losses)  over nGas and close to 22% SAVINGS by GTHP [ now add HW savings, and add a low recirculated HW for radiant designed-SAVINGS, etc., heat-recovery and within and among multi-zoned GTHP ] which supports a (here in town's forum) AiqHTP saving 22% to 27% over propane while GTiqHP is saving over40%, easily... (add the cooling savings of large loop or open well GTiqHP).


While you continue to be not very clear in your writing, let me make a few points here:

1) The purpose of a heat deliver system is to deliver heat, not to store heat. HIgh mass is desirable in a building to a certain degree, but not in the heat delivery system, which you want to be quick responding.

2) While efficient radiant systems use very low supply temperatures, this has nothing to do with high mass, but more with their ability to conduct heat to the above floors effectively.

3) While part of the claim of radiant being more efficient has to do with the assumption that one has the same comfort level at lets say 65F radiant than forced air at 70 f degrees, studies have show that houses with radiant system do not lower their temperatures below comparable forced air systems.

4) Yes, water stores about 3500 times as much energy (heat) and the same volume of air, the distribution can be cheaper. Small circulation pump versus blower. Overall, maybe a 5% saving.

5) Radiant can still save a lot over forced air if you design your system down to the lowest possible supply temperature, making a heatpump fed system more efficient. However, this concept has nothing to do with the mass of the radiant, but, again, with efficient conduction (and a bit convection) of the heat to the above space.
www.buffalogeothermalheating.com
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12 May 2012 10:15 AM
HIgh mass is desirable in a building to a certain degree


I say "may be desirable". For example, if you have an office building used 8 hours/day, mass may ADD to the energy needed in the morning and extend the btu losses into the evening. On the other extreme, if you maintain a steady indoor temp 24x7, indoor mass doesn't help you either.

Exterior mass is less likely to have downsides but it too "depends on the weather".
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12 May 2012 06:05 PM
Posted By jonr on 12 May 2012 10:15 AM
HIgh mass is desirable in a building to a certain degree


I say "may be desirable". For example, if you have an office building used 8 hours/day, mass may ADD to the energy needed in the morning and extend the btu losses into the evening. On the other extreme, if you maintain a steady indoor temp 24x7, indoor mass doesn't help you either.

Exterior mass is less likely to have downsides but it too "depends on the weather".


...TO A CERTAIN DEGREE....

I am mainly looking at residential buildings here,where it buffers the solar gain nicer. In the morning it absorbs the heat nicely, takes longer to heat up during the day, and then carries that heat into the night. That buffering effect is more pronounced in heat dominated climate. But even in an office building, which is more likely to be cooling dominated, you want that building to cool during the day and store that heat during the night, so you don't have to heat it up as much for the crowd arriving in the morning, and then stay cooler during the day.

Yes, if you stop heating at 72 degrees and start cooling at 72.5 degrees, high mass does not help you much, but most people are quite comfortable between 68 and 78F, depending on humidity levels, and this is where high mass houses really shine.

The whole point was that you want the mass in the building, not the radiant system. Putting it into the basement slab is ok, since the basement does not fluctuate as much due to less solar gain, and ground coupling. I can't think about any circumstance where a high mass radiant actually increases comfort and saves you $$$ compared to a low mass radiant system.
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13 May 2012 10:33 AM
I agree. Solar input along with occupants who are willing to tolerate a wider range of temperatures is a case where passive, non radiator mass is useful. In other cases it can be a negative.

Active mass is different in that it is always helpful.
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13 May 2012 10:50 AM
Posted By Dana1 on 02 May 2012 04:34 PM
I've only seen a handful of geo-air systems up close & personal.... but many are multi-stage. ---- [can]  minimize wind-chill from tepid air systems in McMansions, a bit tougher in a 1000' Cape style house.

-looked up 'tepid' for standard def- and always, T's D1:)
 (COMMENT BELOW IS SIMPLY NOT FOR LOAD STUDY NOR BUILDING IMPROVEMENTS) 

just look at heat pump / like low temp air solar:
cfm = half the sq ft in an 8.1/2 high ceiling res. rm.  
= coincides with about 3.1/2 air rotations [not yet just through equipment, here] air-rotations/hr  for  a corner-corner comfort.
Condition 1)
Not any more output air blowing on occupants than would a motel P-Tac wall unit or a mini-split.
Condition 2)
Not open for my time for any argument:
[about  blasted-too-near-to-surfaces = heat exchanged Ex] ONE MUST absolutely only be  leaving at-rest/alone   all unconditioned walls and glass thin boundary layer, of that INSULATING air-film, -that laminate air layer,  undisturbed at mechanical 'rest' for a least EX and a highest comfort,  "screened in front of, not on a wall as Curt (engineer)  put in his first portion of his commentary, clearly-   enough. LCFH on the way that I was thinking anyways.

Condition 3)
Technic-Picking-
With a basis about----
When the glass-radiant heat folks stormed through in 1980's at/in "gas shortage out-cry"-days, 
they left a report on "the architecture of the skin" .
 Relative to no air moving and clothed surfaces in say shirts with sleeves, ~ 74-deg  human in a slow walk or some sitting was read by infra-red scanners. Anywhere 'budding engineers' collect at drafting tables for half of a day, or high school hot headed teens , after winter sports sat in an art room in a basement-like classroom, finished walls, uninsulated, it was been found that an actual air temp of over 72 and usually 73+ on a wall stat IS REQUIRED for hands to function comfortably. (Art-Room of Picasso'ess-Pit, as a sign read at the foot of a stairwell,  Mother/Teacher there kept stat at 73 all winters 1970's)
The boys can argue (at there cost and/of moral)  all day, but the desk worker usually has more comfortable tactile mobility at 73 air about the hands.

yeah D1, engineer, Joe, and all of you , this is but  - a bit subjective,
but concept and practice carried into solar and Air and GT HtPump ducting desiging and comfort that buyers are glad to have.

100 sq ft or 1000 or 10,000...  3 to 3.1/2 air rotations effectually eliminate 'tepid' still air at ~ 78F, some slow moving at 84-86F, and 200 to 400 feet per minute from 88F-92F at out of registers in any system. [will always be my-closer-to-standard-read definition in what as I thought was 'tepid' (it has your definition with a temp , though)]
.  As you mentioned felt and we still see today- 'cool-flows' are in direct contrast to the following:

Old school 450-550 FPM air register velocities ,  unless low budget installs prevailed,  - for some HtPump installations have all but stopped with tricks of 2HT+2CL stats in the 80's grabbing multi-speed blowers wiring for "staging-like" getting 2-'stages' from single speed equipment. Artisan up-to 18 min time delays 'staged' off 1HT stats on a blower-relay addition.

 By the introduction in the EARLY '80's of 3-staging dual compressors of at 30% to 70% to 100% Ex (energy flow allowance) staging greatly improved. (Later copied by TRANE , etc. single refg coil circuiting.)
4 and 5 speed blowers were tap/wire selected for COMFORT. I only noticed in 1996, residentially programmable (tech-plug-into-board) with Pulse-Width-Modulated ECM-1 10%-100% speed selection I used on "SIZE 5.9" GTHP's of two customers .

I did find the tables of comparative MiniIQ and Daiken and GT standard to GT IQ now. (and as you seemed to figure out, was not asking about ducting, though info bites were fun reading DUCT 101 and DUCT 102, again)

DANA:
This was the Q' , you seemed to see/begin to answer,  that I had asked at the beginning:
regardless of subjective def's:
47 down to 5  (and  -5 below zero)
Graphs? Reference tables?
Regular AirHtPump, GThtPump, Mini's and IQ/VerRfg by veraible compressor motor drives ((not a whole lot different than 3-staging, 4-staging from the 1980-'s , I now see, in the field with all the swings. re: OUTPUTS to KWH Consumption, repairs, expense, etc.)) - all considered JUST AT a CONSTANT AIR TEMP output Ex does vary by --- What ? Loaded , in a room...?

I have some answers now.

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13 May 2012 10:55 AM
I see ~ 15% output -some cyclic-defrosting- DROPS Miini/AHPiq
[in other posts: IQ Ver RFG Air Source Heat Pump ===  Aiq  for referencing]
on high speed, fully loaded, as a 3.1/2 " ton" is then running at 5-to-10F above zero, like its rated 3-"ton" at 47F on an ISO standard charting, lab conditions. Since Parkersburg WVa to Cleve to Erie PA, all have nearly EVERY WINTER sub zero weather, just wanted to see a difference, if any different than APPLES:APPLES GT to Air Ht Pumps, today: GTiq:Aiq.

At -5, I can clearly see in humid winter areas:
 more than 30% seasonal cyclic differential in KWH advantage of GTHtP--
 compared to way oversized- to -keep up at a 7-12 deg balance points before needing supplemental heating with AirHtP, in those normal sub-zero winters.

This concurs with the 1993 EPA Nox gas emmisions studies covering Air to GT Ht Pumps in their data, highest-Eff to Highest Eff , then , and that was not compared to the heating of the COP 4.1 TETCO W:A of 1979, heating only GeoThermal. (now built by Enertech, and now Ph4 for HW and Radiant, combo, like a Hydron Combo "module" and others

That "AIR HT P forum" is up in recent posts.

Dj:
Steady-State, mass or not, I read the amps, the data was resounding, 8% to over 10% : the Forced Air GT walked away over the 104deg HW radiant at 4gpm per ton at the gt... like 88Fdeg HW leaving at 4gpm per ton to compare (USED an existing slab for test) to F Air with 72 incoming air. Let's do that analysis at another thread so INITIAL Q's get answered. T's again ! Desiging and all that good info biting is needed.



EDITED for MikeSolar-  "MS"
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13 May 2012 12:02 PM
knotET, I've been around this stuff for 30 years and thought I knew most of the acronyms but I really have a hard time reading your posts (I am trying really hard), but it is making my head hurt. Could you do us a small favour and use the same acronyms that are common to the others in the biz.

Failing that, make a list of some of you more inventive ones so that we can follow along more easily. Thank you.


Somewhere back in this thread it was alluded to that thermal mass is not so important in energy conservation with heat pumps and I believe Dana1 said that a masonry wall has a r-3 value. The current measurement scales have a hard time taking into account the thermal lag and flywheel effect that occurs in masonry homes. I live in a standard 3 story double brick 1800 sq ft home or 1918 vintage and my heating bills are lower than an almost any 1800 sq ft stick frame (nominal R20) home. Point being...I can't see how the point of thermal mass being unimportant is true......comments anyone?
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13 May 2012 12:45 PM
Posted By MikeSolar on 13 May 2012 12:02 PM
knotET, [(kE is fine)] [kE] -brackets
 MS:
I've been around this stuff for 30 years and thought I knew most of the acronyms but I really have a hard time reading your posts [I.E.?- what's the question, or can you just private message, if you want amplification?] 

[2) Gotta answer for the Q' ?]

[3) tangent discussions of the "ducting" etc, mass had little to do eith the real Q; I believe could me given a sign post and send us to more relavant threads to those off-topic writs.]

MS states:
Somewhere back in this thread it was alluded [Politely: just  not by the Q nor the poster] RE: to that thermal mass is not so important in energy conservation with heat pumps .
 [ and that is as a separate thought to me too,  to- ]    and I believe Dana1 said that a masonry wall has a r-3 value.
 
The current measurement scales have a hard time taking into account the thermal lag and flywheel effect that occurs in masonry homes. [((true))] [but I actually touch on how , above. I will decode in another thread on that of yours. Please START a Q'.]

MS states:
I live in a standard 3 story double brick 1800 sq ft home or 1918 vintage and my heating bills are lower than an almost any 1800 sq ft stick frame (nominal R20) home.

Point being
...I can't see how the point of thermal mass being unimportant is true......comments anyone?
Thanks.

"Ex"  x mass "unimportant "  to this Q in the top of the thread, as to  Ex (Ex - is a common term for thermal energy transfer about an HX heat exchanger/. It is in wikipedia, net articles, GEOExchange, 'the Source', etc.).

HtP for Heat Pump, here; 
 please give some type = notice (What is regularly abreviated, of/to you ) on that newthread about the mass and things. 

We can move along.
-only at steady state, about Ex, was the comment about a high temp (in a low mass of plates to flooring) or low temp READ  [occuring] in a high mass, OBSERVED  Ex  device, called the basement flooring  (as at a HIGHER temp radiant [not more nor less WORK was the discussion] to the wood above). COMPRESSOR to temperature of the refrigerant was the direct concern indicated by AMP draw.

It was JUST A READING at an existing home - not a design,  nor had anything to do with ducting, - if I can but amplify for all- .

3)   interesting you mention , "in 1800" 1400 12 inch to lathe walls, 400 cape code finished above, loosely insulated split down to utility and storage next to 3 bay garage. Top 400 is closed all winter until occupied by 1 a few days.... and too, I have below average heating costs, with 2 or 3 deg more comfort! Attic needs more !

4)  a) Thread on ducting
     b)  Thread on mass and slabs and flooring  and distribution sorely needing over 104 LW radiant.
     c)   Thread on YOUR typical mass but you could help me with more pointed singular questions or anyone.

5) This thread Q's) have been completed in answers and by more research. -answered since finding articles, and now that  GTiq is here.  (GTiq: IQ GT HtP Veriable Refrigeration Drive BY a Phase inverted Brushless DC motor in a mechanical compressor for Air and Water and other applications to be distributed COMFORTABLY and EFFICIENTLY as a 'budding engineer' can feel indirectly, but humanly even for months in a womb).

4) d) Solar thread? Too, what can you ask regarding informing and to see others ideas and experiences, please...? 

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13 May 2012 11:27 PM
Posted By MikeSolar on 13 May 2012 12:02 PM
I live in a standard 3 story double brick 1800 sq ft home or 1918 vintage and my heating bills are lower than an almost any 1800 sq ft stick frame (nominal R20) home. Point being...I can't see how the point of thermal mass being unimportant is true......comments anyone?


You give us the best example how thermal mass is very important in buffering the heat for saving energy and comfort is.
Again, thermal mass in a building is good, thermal mass in radiant system is bad. There is a reason why 2000 years ago, or even 100 years ago, building performance was more comfortable and sometimes more efficient than today.

I lived in buildings with 2 foot brick walls for 35 years in Europe, not needing any A/C, and using all the solar gain there is to minimize heating.
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14 May 2012 12:22 AM
Posted By knotET on 13 May 2012 10:55 AM
src="http://www.greenbuildingtalk.com/DesktopModules/ActiveForums/themes/gbt/emoticons/smile.gif">

That "AIR HT P forum" is up in recent posts.

Dj:
Steady-State, mass or not, I read the amps, the data was resounding, 8% to over 10% : the Forced Air GT walked away over the 104deg HW radiant at 4gpm per ton at the gt... like 88Fdeg HW leaving at 4gpm per ton to compare (USED an existing slab for test) to F Air with 72 incoming air. Let's do that analysis at another thread so INITIAL Q's get answered. T's again ! Desiging and all that good info biting is needed.



EDITED for MikeSolar-  "MS"


Let me clarify this. If you design your radiant system as efficient as possible, meaning for a low supply temperature, your W-W heatpump can run more efficient than a W-A heatpump due to lower refrigerant pressured and higher COP. Thus radiant floors can be more efficient in heatpump applications than forced air.
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14 May 2012 07:04 AM
The principal is the same whether ASHP or GSHP. Close up the dT and the efficiency increases. There are two ways to do this on any given house.....reduce spacing or increase mass. The only down side to having high mass in a radiant system is response time, but if the rest of the house is high mass, the temps don't need to fluctuate quickly. We have done a number of off grid houses with radiant stoves, high mass, and the temps rarely vary more than a few deg, even without supplemental heat.

I have seldom seen a reason for low mass radiant except for a builder who is not willing to wait for gypsum cement to dry out properly.
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14 May 2012 11:29 AM
Posted By docjenser on 12 May 2012 01:15 AM
Posted By Dana1 on 10 May 2012 04:20 PM
I've not seen credible 3rd party data to support the notion that the average full system GSHP seasonal COP is in excess of 4 yet, despite the onesie-twosies at the 2 sigma margins.  But if you can show me where to find third party survey data on instrumented & monitored systems such as the dozens of mini-splits in the NW Ductless project I'd be very interested to look at it. The smaller-scale studies I've seen to date all point to mid-3s as the system average.


http://www.builditsolar.com/Projects/SpaceHeating/InField%20PerformanceTestingofGSHP_updated%2011_11_2010.pdf

You are right, good published studies are lacking, the one above is quite bad with very inefficient systems and lots of variances, which make me question the data. We see average total system COP in the mid 4s with 3 ton dual stage W-A, with an average heating season EWT of 38F. We have 15 Welserver online, and should summarize and publish the data.

I'd already seen that one, and it's consistent with several others. Question the data all you like, but until there's published evidence that the industry average has has moved forward from that point, I don't see any reason to believe that a typical GSHP installation are even close to averaging in the 4s yet.  In fact I haven't seen ANY third party tested system that beat 4 as a seasonal average, but I wouldn't necessarily be shocked to find an existence proof some day. Yet I tend to believe people who actually measure stuff when they have no financial interest in the outcome rather than blindly accepting vendors' spec sheets, or the marketing literature/protestations of installers.  Allegations aren't evidence.

Just as with mini-splits- the average in-situ performance of tested systems can hint at what's possible, but from the prospective buyer's point of view it's unwise to assume that you'll beat the industry average.  Best-case scenarios are rare, but of course better-studied better-designed implementations can industry averages.  Just as I wouldn't assume an average COP of 3 for a ductless in US climate zone 5 (even though I believe it's possible with an optimized oversizing factor), I can't assume an average COP of 4 for GSHP based on an installer's say-so or industry-insider lore.  \

Say whatever you like, but show me, and don't be too sensitive when others call THAT data into question.

As a crude measure of where to place expectations, in US climate zone 5, for now I put the backstop at 2.5 & 3.5 for ductless & geo respectively.  While it might be at the lower-efficiency side of dead-center on the bell curve, it's probably within a single standard deviation.  In US climate zone 4  that moves up to 3.0 and 3.5 based on the available evidence.   But the fact that average for one of the zone-4 sub-region in the BPA study was 3.4, the possibility that at least some installation in that mix was averaging about 4, seems likely while others were only 3. 

Of the two non-instrumented systems in climate zone 4 that I have first-person reported billing data on, an average north of 3 would be consistent with the power use.  A 4 average would be a bit surprising, but not entirely out of the question for one of them, but it hasn't been up for an entire heating season yet.

Note that the testers in the BPA study were unable to achieve the HSPFs published by Mitsubishi, either in the lab or in-situ, but were able to demonstrate that their lab measurements were consistent with the field-monitored performance.  But they COULD reproduce the Fujitsu-published HSPF both in the lab and in-situ.  But since Mitsubishi holds the lion's share of the installations in that study it's conceivable it skewed the averages downward slightly.  As the state of the art moves forward it should all be moving up incrementally.


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14 May 2012 08:42 PM
Dana1, here is a link to the IEA website on the development of the ASHP and GSHP. The report is a final one detailing best practices and in it you can find some system performance data. There are some ASHPs with COPs approaching 4 and GSHPs with COPs near5.

http://www.annex32.net/field_monitoring.htm

The difference, in my mind, between North American HPs and European units is partly one of holistic design. We tend to take heat distribution by forced air system as a given which they don't do. It is considered lowest common denominator in Europe and the floor heating or radiators is included in the building design from day one. Forced air would generally not be considered because it takes up space, is more noisy and uses more energy to move the heat than heating with water.

The people I know over there use, for example, tubing with a 4-6" spacing in concrete which can result in 30C EWT and a 5-7C dT. Very different practice from here.
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15 May 2012 01:16 AM
Posted By MikeSolar on 14 May 2012 07:04 AM
The principal is the same whether ASHP or GSHP. Close up the dT and the efficiency increases. There are two ways to do this on any given house.....reduce spacing or increase mass. The only down side to having high mass in a radiant system is response time, but if the rest of the house is high mass, the temps don't need to fluctuate quickly. We have done a number of off grid houses with radiant stoves, high mass, and the temps rarely vary more than a few deg, even without supplemental heat.

I have seldom seen a reason for low mass radiant except for a builder who is not willing to wait for gypsum cement to dry out properly.


The response time is a huge issue in higher efficient buildings, which simply don't loose much heat, and usually have much solar gain.
High mass floors are taking hours to heat up and hours to cool down. They don't give you heat when you need it, and then still heat when you don't need it.
May be you can elaborate how a higher radiant mass will increase efficiency? What matters is the conduction from the pipe to the floor above. Yes, spacing is one way. Gypsum and concrete is a bad conductor, aluminum is much better.
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