anyone here have any experience with this unit using propane?
i'm thinking about a kb080 for my radiant floors but it needs to be reliable on lpg

energywise did my manual j

heatpump    32,228 btuh
furnace        33,840 btuh
hp/ac cooling          24,346

i'm debating between a heat pump and this boiler
i'm a bit ignorant and all advice is appreciated


winter outside temp   26 f
summer outdoor temp  83

btw, i'm about 5 miles due west of dan at blueridgecompany for a rough location


thx in advance for any tips


keith

What do you pay for electricity per kwh, and what do you pay for propane?

Are you doing radiant with all of the above, or hot air for all but the Lochinvar?

The output of the KB-080 is more than 2x your design day heat load, and delivers half your design-day heat load at it's lowest-fire. The WB-050 is a more appropriate size, modulating down to about 1/4- 1/3 of your peak load, and still has sufficient capacity above your heat loads to run an indirect-fired tank for domestic hot water as well. It would be measurably more efficient than the KB-80, spending much more time modulating rather than cycling on/off. They have a good rep, but I have no direct experience with them. With any mod-con, the competence of the installer & system designer makes or breaks it from an efficiency & longevity point of view. LPG vs. NG versions are a minor issue for most- they tend to have similar performance & reliability factors.

In western WA electric rates tend to be lower than the nat'l average, and the average winter temps modest. Air source heat pumps are likely to be far cheaper (like 1/3 the cost) to operate than condensing propane, and not dramatically more expensive to operate (and much cheaper to install) than ground source heat pumps. The available hydronic output air-source heat pumps are few however. (The Daikin Altherma, and a few other Japanese hydronic models are available in the US, but finding the right contractor to install & support them near you is key.) The extra installation costs of ground source heat pumps would never pay back in the modest efficiency gains over air-source units in your climate.

thanks for the response dana1

0.10 or so per kwh here
2.25-2.50 a gallon for propane

and the whole house will be radiant

i had no idea a heat pump was that much more efficient (read cheaper to operate) then propane

that daiken altherma looks to be the ticket but they are not exactly abundant here from what i can see so far
it seems there is a local heating company in town though that is a rep for them so i will check them out

again, thx for the insight

keith

Propane has ~91500 BTUs/gallon. Burned at 95% efficiency in a mod-con delivers ~87000BTUs/gallon to the radiant floor. Normalizing that to $/100KBTU, (100KBTU==1 therm) at $2.25/gallon that's $2.25/0.87= $2.59/therm.

Electricity in a resistance heater at 100% efficiency takes 29.3kwh to deliver a therm, so at $0.10/kwh it costs $2.93/therm to run resistance-heating.

But a heat pump in your neighborhood will deliver an average coefficient of performance of 3.0 (300% efficiency) or better, which means for every kwh it uses, it delivers 3kwh of heat on it's output. In other words it takes ~1/3 the electricity of a resistance heater to deliver the same heat. For you that means with a heat pump you'd be paying $2.93/3= $0.98/therm of heat delivered to the floor.

$0.98/$2.59=0.38

With a heat pump your heating bill would be 38% of what it would be with a propane mod-con, 62% reduction in operating cost(!). So if it was going to cost you say, $1500/year (~650 gallons @ $2.25-2.50/gallon, which may be on the low side in your climate, with your peak heat load) to heat with propane, with a heat pump you'd pay about $570.

Daikin isn't the only player. IIRC Mitsubishi has a hydronic air-source heat pump available in N. America, as do a couple of other major Japanese players. Daikin Altherma is on my radar screen because it's one of the few air-source heat pumps that still delivers a COP better than 1.0 at temps well below 20F. (20F is close to my winter-time average.)

The lower you can make the water temp on the radiation, the higher your COP will be. Radiant slabs, and above-the-subfloor systems like WarmBoard etc. are your best bet, but if it's a sub-floor staple up it'll be well worth the extra $ up front to use extruded aluminum plates instead of the sheet-metal flavor. A difference of 15F on your water temp requirements could be worth 0.5 or more in average COP. Hopefully the local heating guys repping Daikin can sort this all out for you. If you can keep your peak load water requirements under 100F the performance will soar. If your local guys need guidance, there's a contractor in Portland OR that has successfully installed the Daikin Altherma. (See: http://www.jacobsheating.com/press ) They're relatively new to the US market, but they've been installing them in Europe for a few years now.

Off-peak rate?

Even standard electricity rates in the Pacific Northwest tend to be on the cheap side relative to the national average. Most PNW utilities offer lower rates for those who heat with electricity too- if that's the case with kotero's utility, a Daikin Altherma or similar would be an EXTRA-SUPER no-brainer compared to propane. There are no "deals" on propane, and the current pricing is something of a market low. Propane pricing is quite volatile, but my expectation that it will never see parity with PNW electricity used at a COP of 2 or better. And electricity pricing is regulated, more predictable.

Heat pumps vs. condensing NG are often competing head-to-head though- it's not a no-brainer, and needs to be analyzed relative to local climate and available utility rates. My brother probably shares a utility market with kotero, based on the approximate location description, but heats primarily with wood, with propane as backup. Were he to ever get tired of splitting wood I'd be pushing a heat pump solution at him, since he's far enough away from the gas-grid that it's unlikely to ever be an option, and heating with propane gets to be expensive. During the last oil-price spike even resistance electricity at full retail was cheaper than 80% AFUE propane for him.

Heat pumps cost money...I would look at off-peak electricity and an electric boiler.

Maybe if he can get 3 cent electricity it makes sense to go off-peak (if it's even available to residential customers) with an electric boiler, but at his heat load & climate heat pump installations may be different from what you're used to. You'd have to price it out and run all the numbers, but if it comes in at $750-1K USD/annum difference in operational cost it's probably present-value positive to go with air-source heat-pump. It's a ~5500HDD climate, with January average temps in the 30s. COPs are quite reasonable in that climate with air-source heat pumps, and lots o' folks on the foggy-dew Olympic Peninsula heat with them (even in low-cost housing.) It remains to be seen whether the hydronic Daikin Altherma come in anywhere near as low as the usual hot-air flavored versions though. I'd expect it to be ~2x as expensive as a 3-4 ton hot air system, but may still come in comparable or less than a mod-con intall.

The more common rate-discounting for residential customers out there is a 25-30% break for "all electric" homes on power usage above some monthly minimum, an artifact of when they were pushing to find a load for all of the BPA dam projects. As a result there are MANY homes in that region heated with electric baseboards, electric radiant (the old, crummy stuff) or electric hot-air. With the huge amount of development in Seattle & Portland metro areas over the past 25 years they no longer have excess power to dump- they have grid-capacity problems instead, and conservation/efficiency is starting to be pushed significantly to free up capacity for new development. There may even be subsidies for going heat pump in his utility district if lots of people are currently heating with electricity, soaking up most of what would be off-peak surplus in most other areas. MANY local districts there experience their annual peak grid loads during heating design-day temps during pre-dawn hours, and have to plan extra generating capacity based on the weather forecasts. (My cousin's spouse is a powerline engineer for one of the public utilities near Seattle- I get an earful when I visit.)

Point taken.

The Daikin appears to be about 2x-3x the cost of a mod/con install, maybe plus a few bucks, unsubsidized. it promises a seasonal COP, with DHW production, of about 3 in a climate like belgium which i believe is similar to new england. I expect it to be a bit higher without the DHW component based on my belief that DHW production is not the best use of the unit.

It can really shine for cost effectiveness if you are doing heating and cooling with it... chillers are not cheap either. for straight heating though it might be an uphill battle as the cost is between geo and boiler, but the output is low at cold temps (18kBTU at -4deg F., which happens to just about be our design temp here in maine). Geo usually only makes sense for larger heat loads, but this can't service such large loads.

We have had our running here at our shop for a week now. Monitoring equipment is not installed yet so no initial feedback and today we seem to be unable to get the office area below 73 degrees even without any calls for heat... guess we did too good of a job with our envelope!

I should mention it has backup electric resistance built in; 18k output is heat pump only. ours is a 6kw backup which should help it reach our design load of 35kBTUs/hr.

Posted By NRT.Rob on 26 Mar 2010 01:31 PM
The Daikin appears to be about 2x-3x the cost of a mod/con install, maybe plus a few bucks, unsubsidized. it promises a seasonal COP, with DHW production, of about 3 in a climate like belgium which i believe is similar to new england. I expect it to be a bit higher without the DHW component based on my belief that DHW production is not the best use of the unit.

It can really shine for cost effectiveness if you are doing heating and cooling with it... chillers are not cheap either. for straight heating though it might be an uphill battle as the cost is between geo and boiler, but the output is low at cold temps (18kBTU at -4deg F., which happens to just about be our design temp here in maine). Geo usually only makes sense for larger heat loads, but this can't service such large loads.

We have had our running here at our shop for a week now. Monitoring equipment is not installed yet so no initial feedback and today we seem to be unable to get the office area below 73 degrees even without any calls for heat... guess we did too good of a job with our envelope!

OUCH!  It might take a sharp pencil  on the financial analysis on that one then!

Western WA climate is more similar to Belgium than Belgium does to New England.  The former are ~5000-5500HDD climates, with less severe peak loads, and somewhat longer heating seasons.  I've also lived next door in the Netherlands, a country where 72F is considered too hot to stay in the office- they're obligated by law to sit outside at the corner cafe and drink beer when it's THAT hot!   Being down wind of the Pacific Ocean or North Sea brings coolth to the shoulder seasons, but moderates the winters considerably.

I'll bet the hydronic version would handily beat a seasonal COP of 3 in heating-only mode in WA.  Design-temps in western WA below 1000' of altitude run ~10-15F, daily averages well above freezing.

you know, it might have been denmark. I need to go back through the lit. l I'm much more interested in my own monitoring anyway! unfortunately, today with 35 degree peak outdoor we peaked at 75 degree indoor with no heat demands all day long in the office. Warehouse demands only, sniff sniff.

Perhaps the individual that did your heat loss was, uh, undertrained...

dana1
i think you created a heat pump monster here
the house will be all radiant, pex in warmboard, icf construction, foam in attic

it appears that water to water pumps are more common the air to water so i start thinking , hmmm
i have 5 acres and a backhoe and dozer , how hard could it be?
a couple -3 horizontal slinky loops about 6-7 ft down, 1.25 hdpe, hmmm

this could get interesting

Posted By kotero on 28 Mar 2010 08:34 PM
dana1
i think you created a heat pump monster here
the house will be all radiant, pex in warmboard, icf construction, foam in attic

it appears that water to water pumps are more common the air to water so i start thinking , hmmm
i have 5 acres and a backhoe and dozer , how hard could it be?
a couple -3 horizontal slinky loops about 6-7 ft down, 1.25 hdpe, hmmm

this could get interesting

Your heat load is pretty small- many/most the water-water/geo heat pumps are oversized on output, and may incur significant cycling losses.  Design before digging.  This doesn't easily lend itself to DIY design, and correcting errors may be outlandishly expensive. Snoop around the geo forum on this site while contemplating...

Rob:  Denmark's climate isn't significantly cooler than the Benelux countries.  Denmark is surrounded by the North Sea and Baltic and gets warmer temps than Belgium when the wind is from the east,  similar temps when it's from the north or west.  (It's a lot like UK weather.)  The hundred year HDD average for Copenhagen is ~3200C-HDD (~5800F), which is similar only to southern New England coastal areas.  But it's spread over many more days (they have essentially ZERO cooling season in Holland & Denmark), and the peak loads are lower in Copenhagen than they are in Boston or Providence despite similar total HDD.  On the eastern end of the Baltic the cold snaps can get pretty cold though. (Estonia/Finland might be a better comparison to non-coastal New England.)  Sounds like you need to turn off some lights & equipment &/or get serious about solar gain control well before summer- 75F interior temp during a significant heating load outdoor temp? I hope you have the Daikin set up for cooling as well!