I moved this to a new thread since, while still relevant for the homeowner who wanted some advise, is getting off topic. AHRI/ISO 13256 rating is done at 32F EWT for heating geothermal heat pumps. http://www.waterfurnace.com/literature/5series/SC2500AN.pdf for dual stage (water furnace). Page 6 gives you the rating, page 8 tells you what is included in the rated COP, including 68F entering air temp. http://www.waterfurnace.com/literature/5series/SC2506WN.pdf for w-w, page 27 gives you the 13256 -2 rating standard table with 32F EWT and 104 entering load temp. For a 4 ton unit as I mentioned as an example, COP is 3.1 for the water-water unit versus 4.0 of the water-air unit. 22.5% less efficient for the w-w. Just by example: Hydronic water air handler (water furnace) http://www.waterfurnace.com/literature/envision/SC1008HN.pdf Page 17 gives you the capacity at different water temps. Using again the 4 ton example, the air handler needs 120F water to put out 39,000 BTUs. They are usually rated at 114F entering water temp. So the numbers are very real. The rating standard used to compare units across the board uses 32F EWT as a standard. I challenge you to find an air handler which puts out its nominal rating below 114F . Fan power is partially included in the 13256-1 rating, the fan power of the air handler is not, dragging your COP down further. You don't seem to understand that a system which has to go through an additional heat exchange step (refrigerant to water to air) will be inherently less efficient than a simpler refrigerant to air process, especially when the higher operational temperatures are needed for the water-water units to have any air handler perform at the rated capacity.
Still made up numbers. I am glad I do not trust my money to your math. Page 26 does not use EWT of 32*F. What you think is transportation loss of the BTUH, is offset by using pumps and small pipes rather than big ducts and big blowers. Even WF uses Robert Bean's work on radiant cooling. Radiant cooling does not need a blower, just a drain.
If you accuse me of made up numbers and incorrect math, against the evidence and documentation you yourself had asked for, be specific. I did not say page 26, I did say page 27, which displays the ISO/AHRI rating 13256-2 for a state of the art water-water unit and uses 32F entering water temps for closed loops, as does every other manufacturer. The purpose of the the standardized rating is that units become comparable among different manufacturers, and yes, with single stage units they all use 32F entering source water temperature, and 104F entering load temperature, which usually gets you to around 114F leaving load temp. Table is attached. http://www.waterfurnace.com/literature/5series/SC2506WN.pdf The discussion stems from the thread below where the OP wanted to replace 2 forced air furnaces with a geo system. He is located in New Jersey. Not sure why radiant cooling, which I would argue is not really thesiable to deal with the humidity issue in New Jersey, now comes in the play. https://www.geoexchange.org/forum/threads/what-is-a-good-value.6793/ The blower and pumping power is partially included in the ISO/AHRI 13256 rating and accounted for, and modern ECM blowers do not use much more energy, usually less than 40 watts/ton in low stage heating where they run most of the time. What is not included are the blowers of the 2 air handlers in the case discussed what you had proposed, which would add to the power consumption and further reduce the COP. Rated EWT of the 13256 rating system, loss of efficiency in water-water applications with air handlers, or what is included in the rating and what is not is something every experienced installer/designer should know of heart. It beats me why you continue to dispute all that when this is clearly documented. Again, be specific if you want to challenge it.
My typo. should be page 17 not 27. I still do not see 32* water. Radiant cooling works fine if one keeps the water temperature above the dew point. If that is not possible use a chilled beam with a drain. Put it near the ceiling and no blower required. Gee I don't remember typing anything about ratings. I do not remember specifying any equipment except the drain.
Too funny. Let me explain that again, here is what I said: "Just by example: Hydronic water air handler (water furnace) http://www.waterfurnace.com/literature/envision/SC1008HN.pdf Page 17 gives you the capacity at different water temps. Using again the 4 ton example, the air handler needs 120F water to put out 39,000 BTUs. They are usually rated at 114F entering water temp." So I gave you an example including the manufacturers documentation, that hydronic air handlers usually require 120 Entering Load Temp to achieve their rated heating capacity (since you were questioning that), thus very negatively impacting the COP of the heat pump, since the water has to be too hot to run the heat pump efficient. So, in the geo world, EWT refers to entering water temperature coming into the heat pump from the loop field. LLT refers to leaving load temperature going from the heat pump to the distribution system. So NO, you would not find 32F specified as entering water temperature for for air handlers, 32F is the standard EWT for heat pumps where their efficiency is measured and compared in heating mode, not the standard rated temperature for air handlers in heating mode. We would all be freezing in the winter. So again, do you have any specifics why you claim the numbers you requested as examples are made up?
