I am more inclined to pick the York , it is easier to find all the expanded performance data for them. I would like to know more about the trane but I can't seem to fine the performance data so i can get a balance point.
Addressing use of 2.5 ton XL15i with 1,200 CFM [ARI 5021599] for a calculated 24,000 BTU/HR at 10'F.
One might expect a Balance Point near 20'F ( +/- 4'F) if heat loss calculation is accurate within 10%.
No heat loss calculation is KNOWN to be accurate within 10%
without a measured infiltration and known window characteristics.
See attachment for "visual explanation".
Also, heat loss at 40'F is half the capacity of this 2.5 ton heat pump,
so one may guess run times to be near or < 50% when the Outside Air is > 40'F.
Designer Dan
It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE
Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities
If the load calculation is close to accurate it seems to be a good choice with a 3kw Aux heat to supply 8000 btu's/hr when needed.
I have added 25% to the numbers I get with HVA calc and come up with 27000 heat loss @ 20 F
I am also thinking of going with a 3 ton 2 stage so more heating at high and sufficient cooling in low stage. Would that be OK or too oversized.
Would that be enough to take the chill out when the system defrosts?
Someone if finally suppose to show up here next week and do a load calculation.
If the load calculation is close to accurate it seems to be a good choice with a 3kw Aux heat to supply 8000 btu's/hr when needed.
I have added 25% to the numbers I get with HVAC calc and come up with 27000 heat loss @ 20 F
I am also thinking of going with a 3 ton 2 stage so more heating at high and sufficient cooling in low stage. Would that be OK or too oversized.
Would that be enough to take the chill out when the system defrosts?
Someone if finally suppose to show up here next week and do a load calculation.
Jimmy
I suspect your calc is probably accurate.
However, infiltration is nearly Always somewhat of an Unknown.
3 Ton __ First stage balance point = ~ 30'F.
3 Ton Second stage balance point = ~ 15'F.
.:. Minimal use of heat strips.
On whether a 3 Ton is a good overall heat pump selection, I am a bit ambivalent.
It would seem to be appropriate and economical for Winter conditions.
Maybe you'll get some Other opinions here from techs who know.
Designer Dan
It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE
Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities
Simplification [10 minutes work instead of 35 minutes] ... 3 ton 2nd Stage is assumed = 1.17 * data for 2.5 Ton XL15i
Conceptually IT IS GOOD.
I doubt that 3 Ton 2 stage data would yield a Balance Point more than 1.5'F different than presented for 2nd stage.
Similarly, First stage of 3 Ton is = 1.9 Ton which is probably a little lower than an actual 3-Ton 2 stage unit ( might be ~2.1 T).
But, you 'got the picture'.
That's WHY I say: It's not rocket science, But IT IS SCIENCE with "Some Art".
If one wished to make it complex, I am going to tell one to break a year into 6 minute intervals ... 87,600 intervals.
K I S S
Designer Dan
It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE
Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities
If I were in your shoes I would do a home energy audit and fix issues with the house and duct system rather than spending the extra on higher end equipment and get tge load down to 2 tons and use a single stage 14/15 seer York LX IMHO
If I were in your shoes I would do a home energy audit and fix issues with the house and duct system rather than spending the extra on higher end equipment and get tge load down to 2 tons and use a single stage 14/15 seer York LX IMHO
If his calculation is appropriate, I don't see much room for improvement.
I do recognize the cost increase from SEER 15 to 16 [ one stage to 2 stage] is likely more significant than from SEER 13 to 15 (both single stage).
Designer Dan
It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE
Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities
Reply With Quote
Balance Point Chart provided ... thanks to Ryan H's link
Originally Posted by RyanHughes
Subscribe to this feed
