Hi everyone, I’m down that rabbit hole where many of you have already been and others will eventually be – looking through Mitsubishi’s submittals and technical specification documents to get estimated heat pump performance across temperatures based on extrapolations from the design loads calculated by my mechanical engineering consultant. I’m trying to decide between two 12 kBtu units or one 24 kBtu unit based on COPs across the entire temperature range while accounting for how much to the annual heat load occurs at each temperature (using NEEP’s database for that). This priority, annual hyperlocal efficiency, is at odds (sometimes) with how much low-load short cycling will occur. 

I think there are errors in the specifications for the SVZ-KP12A+SUZ-KA12NAHZ combination. An alternate explanation is that I don’t understand something, and someone here will enlighten me.

The documents I have extracted information from are:

SVZ-KP12A+SUZ-KA12NAHZ (p. 35)
http://mylinkdrive.com/viewPdf?srcUrl=http://s3.amazonaws.com/enter.mehvac.com/DAMRoot/Original/10006%5CM_SUZ-KANAHZ.TH_TECHNICAL%20DATA.pdf

SVZ-KP24A+SUZ-KA24NAHZ (p. 15)
http://mylinkdrive.com/viewPdf?srcUrl=http://s3.amazonaws.com/enter.mehvac.com/DAMRoot/Original/10007%5CM_SUZ-KA24NAHZ-R1_ENGINEERING.pdf

The power input values for the 12 kBtu system at the three coldest temperatures at max capacity seem incorrect compared to the trend of other data for this system and the 24 kBtu system. I’ve attached a screenshot with those three values highlighted. I’ve also attached a 3 page pdf of graphs that I have made of this tabular data. Pages 1 and 2 are direct plots of the tabular data from the referenced documents. Page 3 is calculated COPs based on the heating output converted from Btu/hr to kW and then dividing by power input. Each page on the pdf is a comparison of the 12 kBtu and 24 kBtu units for heat. The potential errata impact the 12 kBtu graphs on pages 2 and 3 (data points represented by open circles).

I’ll stop here and clarify, if needed. If these are errata, does anyone have a contact at Mitsubishi where we could get clarification? If they aren’t, and I’m just misunderstanding something, then I look forward to your explanations.