Hello eQuest users;
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I have 3 questions that are all related to each other. I am fairly new to energy
modeling, so please help me resolve these issues that I have been struggling
with for quite some time now:
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?Our project is a 17-story residential condo building in Monterrey, Mexico. The
HVAC system for each of the living units consists of a mini-split heat pump
system with 3 zones sharing an exterior condenser.

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1) I don?t think I am specifying the proper HVAC system type:
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In Wizard mode under the HVAC system definition, if I select the system type to
?Split System Single-Zone Heat Pump (residential)?, system per zone, and cooling
& heating sources both as ?DX coils? with heat pump source ?Air? ? in DDedit
mode, the HVAC system defaults to a PVVT system. Is this really the same thing?
Similarly, when I model the baseline building as a ?Packaged Terminal Heat Pump?
in Wizard mode, the HVAC system defaults to a PTAC system in DDedit mode, which
according to ASHRAE 90.1 is a completely different (an incorrect) system type.
When I attempt to change either of these types manually in DDedit mode, none of
the desired systems are available in pull-down options. How then can I
appropriately set the correct HVAC system types?

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2) There is no Space Heating occurring in my simulation:
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Every time I run a simulation, no matter how many options I seem to vary, no
Space Heating occurs for any of the HVAC system zones.? I have input the
manufacturers specified heating & cooling capacities for each zone and have even
tried varying the HVAC system types and capacities, but I simply cannot get any
heating to occur. Allowing eQuest to autosize the capacities yields slightly
more success, but if I know the actual capacities, shouldn?t I model them as
such? However, I can get different results if I vary the inputs related to my
last question:
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3) Lower input U-values indicate more energy use while higher input U-values
indicate less energy use. This same result consistently keeps happening for
windows, walls, anything. Shouldn?t the exact opposite result occur? In regards
to question 2, if I input a ridiculously high U-value for the exterior walls,
say 13.7 (the R value equivalent of the actual 0.073 U value), I finally get
some Space Heating results...
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In DDedit mode, under the ?Constructions? component, I have set up inputs for
the building?s U Values using the ?Layers input? as the Specification Method;
and for the layers/materials I basically just set up 1 layer that corresponds to
the entire assembly thickness and total U-value. I originally set up the
proposed design with several different layers, but I later changed it so that it
could more closely relate to the baseline input because I was not sure how to
set up the baseline assembly layers only knowing the required minimum R Value as
per ASHRAE 90.1. Honestly I get the same result whether I use the U-value input
or Layers input, but I assumed the Layers Input would be more accurate as it
accounts for wall thickness.
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I sincerely thank you in advance for any help that anyone can provide. I am not
an engineer, so I greatly appreciate any advice that I can get. Attached are the
.inp, .pd2, and weather.bin files.
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Chris Toothaker