Quest M-CoRR dehumidifier technology – GreenBuildingAdvisor

Since we’ve had some fun talking about advanced dehumidifier technology recently, I thought people would interested in the four-refrigerant-coil design that Thermastor (parent company of Santa Fe) uses in their most efficient Quest branded dehumidifiers, which they call M-CoRR for Multi-Coil Refrigeration Recovery.

Their page on it, https://www.questclimate.com/m-corr-technology/, includes a 40 second animation that sort of explains it.  There’s a fun youtube video that does explains it more thoroughly: https://www.youtube.com/watch?v=-vwjDABWk7M

They’ve also just released data on new models that use lower GWP refrigerants: R454B which has GWP = 466, which is 22% of the GWP = 2088 of R410A.

Some performance benchmarks:  [edited to report numbers all at the same energy-star/DOE new standard conditions, 65 F, 60% RH]

Portable Energy Star requirement:  1.8 L/kWh 

Compact whole-house Energy Star: 2.09 L/kWh 

Energy Star for units in a larger box: 3.3 L/kWh

Best heat-exchanger based Santa Fe R454B unit: 2.81 L/kWh

Best R454B M-CoRR unit from Quest: 2.63 L/kWh 

[or, at 80 F, those last two are 3.54 and 4 L/kWh–at higher temperatures, the M-CoRR design is better whereas at lower temperatures, the heat exch. design is better.]

It’s not actually that much more efficient than the heat-exchanger approach we discussed earlier this week [even at higher temperatures], but the approach is really clever:

The air flow path is across a mid-pressure evaporator to cool the air towards the dew point, and then across a low-pressure evaporator to drop moisture out of the air.  That very cold air then goes across mid-pressure condensor that re-condenses the refrigerant before it goes through an expansion valve and into the low-pressure evaporator.  Finally the air goes across a high-pressure condensor (not shown in the attached diagram) where the air takes up the extracted heat as sensible heat. 

The cool think about this is that the refrigerant is evaporated and condensed twice even though it only goes through the compressor once.  From that perspective it makes sense that you get about twice the L/kWh that you get from a regular two-coil dehumidifier. 

You can also think of the function of it as being a different way to do the heat exchange that the Santa Fe does with an HRV-core type heat exchanger.  And the results are similar in terms of L/kWh–the Quest products’ market positioning seems to be more as larger scale units for commercial applications.  But where the capacity ranges of the two lines overlap, the M-CoRR approach does yield higher efficiency.