Heat pumps, over there and back
I've been reading the forums on and off for many months now. And I have a quiet reflection...
There seems to be a great difference in heat pumps both technology and trust, between Sweden and most of US.
Just for comparison I'll put in some data from heat pumps in Sweden, used in Swedish (cold) climate:
Since recently heat pumps for domestic use are sold and installed as full coverage - No additional heating source. The COP is currently well above 4.
(COP>4.2 according to testing standard EN14511 and/or EN255)
When I read the debates on theese forums, I get the feeling that heat pumps in the states are:
1. generally not as competitive (compared to data above)
2. Mostly considered a alternate (not as reliable) heat source
Am I totally off? I don't mean to offend anyone but I'd really love a clearer picture on this topic!
Heat pumps in the U.S. are wrongly considered mild weather heating systems that do require a secondary source of heating in most cases. There is a new, low temperature heat pump that is becoming more populare called Acadia, but we still have a ways to go to be competitive with what you are stating.
Do you have any links to heat pumps you are using?
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Two compressors,variable speed?
Originally Posted by Recessor
Air source,or water source?
I will be installing a new heat pump within the next few years.
I would be VERY interested in one that would be a 100% heat source rather than having to have a backup heat source.
My experience thus far, with heatpumps has been very poor low temperature performance. This may not be true, only my experience with them.
Links and more information would be very nice.
I would be more concerned with who did the loop.
There have been dozens of loop companies in town now defunct. There are a few others that are great to deal with and super pro,s
You sure are cocky for a starving pilgrim.
The design of the heat pump depends on the respective market.
Originally Posted by dash
One or two compressor cabinets are avaliable, also there's the ability to cascade a number of heat pumps. Fixed speed or inverter controlled.
The energy source are ground, bore or air. All with its different pros and cons.
Air is cheaper but sound more and don't provide passive cooling.
Ground is silent but like air it varies in overall COP over the year. Does not provide passive cooling.
Borehole is same COP over the year and it provides passive cooling but cost more to install.
Refrigerants are 134a or 407c (In our machines)
Links, I feel secure in providing them as they are avaliable freely over the Internet
Data on specific type: http://en.ivt.se/products.asp?lngID=623&lngLangID=1
Homepage of my company: http://en.ivt.se For some reason this wouldn't work in my Firefox but did so in Explorer?
I'm guessing we'll find the difference in pricing... In Sweden a 9kW heat pump including warmwater cylinder costs about 6500 $ according to Google, add installation and borehole to that. A heat pump of this size heats a house of 4-6 family members in a 3-5 bedroom house of about 150 square meters (According to Google this equals to about 1600 square feet).
From my understanding the insulation standards between our countries are the next obstacle...
Last edited by Recessor; 07-13-2009 at 07:15 AM.
Reason: I was not born a spelling bee...
Better Air Source Heat Pumps
I also believe that most European countries have smaller homes that are built extremely tight with a ton more of building materials that create less of a heat loss load. Plus you folks seem to be able to go without heat for a while if broken and the average American is going to complain if the house goes below 2 degrees of their thermostats set point.
Don't you guys build tighter homes? We need to compare apples to apples and take into considerationg the different life styles and expectations. For instance, most of your heat pumps are strickly heat pumps and not A/C's, right?
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I don't know if the houses are smaller, but I do beleive the walls are thicker (and the roof). Insulation depends on era of construction, but 10 inches is a pretty median standard (glass fiber wool) about twice as much in the roof (cieling?).
Originally Posted by DeltaT
About the complaining part... The temperature with a heat pump is very stable. But the customers DO complain if it gets chilly, no doubt about that.
Luckily it's a rather rare occurence that a heat pump fails.
Finally yes. As for the Liquid/Water, Air/Water heat pumps, they are not A/C modules. However, the Air/Air are. (Or were, they are getting real good capacity and quality nowadays).
Our heat pumps are heat pumps, true. That means they have their best performance at according temperatures. But it IS possible to get cool from them, both in passive and active mode (passive only for bore hole).
Last edited by Recessor; 07-17-2009 at 04:40 AM.
Reason: Added information
Thank you for the link. I've forwarded it to my collegues.
Originally Posted by jchaters
We did check in on the Subadan technology a while back, but we didn't find it optimal for our applications at the time.
Last edited by Recessor; 07-17-2009 at 04:44 AM.
Reason: Spelling, always with the spelling...
I think one of the biggest differences between the European and US heat pumps is that the US units are reversible providing heating and cooling with one unit. Our heat pumps could be sized to cover 100% of the heating load but would be grossly over sized for cooling. So we're forced to compromise. Size for cooling and make up the difference in heating with auxiliary heat. There is also a matter of economics. It's much more expensive to install a 2-speed 5-ton that will cover heating and cooling demand than it is to install a 2-ton with auxiliary heat.
Yes, that would explain the difference in coverage that I have understood to be there. Ours are reversible also, but I think energy costs in Sweden and most of europe motivates us to install full-size heat coverage.
Another thing I don't quite get is "ton" how does that compare to kW?
Or, does it at all?
1 ton = 12,000 btu. You can surely convert from there.
Originally Posted by Recessor