how to determine enthalpy recovery ratio

asked 2021-02-26 19:09:16 -0500

willyJohan gravatar image

updated 2021-02-26 19:11:47 -0500

I'm trying calculate the 90.1 appendix G baseline Fan power limitation pressure drop adjustment for energy recovery devices as outlined in table 6.5.3.1-2.

How does one calculate the enthalpy recovery ratio?

The formula is pretty straight forward (formula C8 in https://www.ahrinet.org/App_Content/a...) but conditions at which h1, h2, and h3 are calculated is confusing me.

Basically I'm trying to figure out how one calculate this value from the input parameters of the HeatExchanger:AirToAir:SensibleAndLatent EnergyPlus object:

  • Sensible Effectiveness at 100% Heating Air Flow
  • Latent Effectiveness at 100% Heating Air Flow
  • Sensible Effectiveness at 75% Heating Air Flow
  • Latent Effectiveness at 75% Heating Air Flow
  • Sensible Effectiveness at 100% Cooling Air Flow
  • Latent Effectiveness at 100% Cooling Air Flow
  • Sensible Effectiveness at 75% Cooling Air Flow
  • Latent Effectiveness at 75% Cooling Air Flow

I'd like to repeat whatever process was done when developing the 90.1-2019 prototypes. I've backed into an enthalpy recovery ratio of 0.3637 be comparing San Diego (no ER) with Atlanta (Has ER), but I can't see a way to get there from the effectiveness numbers in the EnergyPlus object

PS how is there no "psychrometrics" tag?

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Comments

I just came across this text in the 2011 PNNL report "Achieving the 30% goal: energy and cost...":

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"The fan energy associated with energy recovery is modeled as the wheel parasitic power [...] since the ERV may be bypassed when energy recovery does not save energy"

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Is this still the case? and, if so, why does it appear that fans serving systems with energy recovery are modelled in the latest Ptypes with a greater pressure rise than those without energy recovery (all else being equal)

willyJohan gravatar image willyJohan  ( 2021-02-26 20:06:04 -0500 )edit