eQuest Runaround Heat Recovery

Topic: Simulating runaround heat recovery in eQuest requires modifying the standard air-to-air heat recovery system

Suggest selecting system 'PSZ' for DX cooling or 'SZRH' for chilled water; other system selections may work satisfactorily. The following parametric components were utilized to obtain a combined $5,000 in savings (initially, without parasitics) on a $90,000 per year utility bill in the Pacific Northwest on a pair of 'PSZ' systems with heat recovery using 100% outside air.

$ Adjust the supply and returns statics of the main unit to
$ account for the increased pressure drop, originally:
$ SUPPLY-STATIC = 5.25
$ RETURN-STATIC = 2.60 (less delta-P, due to partial exhaust flow)
$ Example, given the above initial statics
SUPPLY-STATIC = 6.00
RETURN-STATIC = 3.00
$ Change the following keyword to YES in a parametric run; all other heat
$ recovery parameters are ignored when set to NO for the baseline case:
RECOVER-EXHAUST = NO
$ Runaround heat recovery recovers sensible energy only, no latent
ERV-RECOVER-TYPE = SENSIBLE-HX
$ Specify OA and EXH flows if only a portion of the exhaust is recovered
$ Partial recovery example
ERV-OA-FLOW = 46960
ERV-EXH-FLOW = 28590
$ Potentially the effectiveness can increase to 0.75 if a two-pass coil used
ERV-SENSIBLE-EFF = 0.53
ERV-RUN-CTRL = OA-EXHAUST-DT
ERV-RECOVER-MODE = OA-HEAT/COOL
$ FLOAT gives maximum heat recovery but recovers even unwanted heat, so
$ use the setting for temperature control
ERV-TEMP-CTRL = MIXED-AIR-RESET
$ modulation capacity control simulates variable-speed pumping
ERV-CAP-CTRL = MODULATE-HX
$ input maximum runaround pump power consumption here, it will be switched
$ on only when the ERV is activated
ERV-HX-KW = 4.5
$ use main unit's fans for heat recovery
ERV-FANS = HVAC-SUPPLY/RETURN
$ Keywords STANDARD and PREMIUM may alternately be specified here
ERV-MOTOR-CLASS = HI-EFF
$ Set the ERV statics to zero, since it is NOT a separate unit
$ in series with the main unit; i.e. pressure losses are 'unswitched'.
$ If left undefined, they will default to 1.5 inches:
ERV-OA-STATIC = 0
ERV-EXH-STATIC = 0
$ This setting eliminates condensation and frost simulation warnings
ERV-FROST-CTRL = USE-CAP-CTRL

However when the parasitic loads of the additional supply/return fan energy and runaround pump power are accounted for, eQuest demonstrates again that is difficult to break even with runaround heat recovery in this relatively mild maritime climate:

(click on the image to see a larger version)

eQuest Standard Reports

Topic: Suggested eQuest output reports for inclusion in ELCCA appendices

Input Data, Appendix B

Text (Simulation) File Reports:

• LV-A General Project Parameters, for selected alternative
• LV-B Summary of Spaces, for selected alternative
• LV-D Details of Exterior Surfaces, for selected alternative
• PV-A Plant Design Parameters, for each alternative
• SV-A System Design Parameters, for each alternative

Output Data, Appendix C

Text (Simulation) File Reports:

• BEPS Building Energy Performance Summary, for each alternative
• SS-D Building HVAC Load Summary, for each alternative
• SS-E Building HVAC Load Hours, for each alternative

Graphical Reports, Single-Run:

• Monthly Energy Consumption by Enduse, for each alternative
• Annual Energy Consumption by Enduse, for each alternative

Graphical Reports, Comparison:

• Monthly Total Energy Consumption, comparison of each alternative
• Annual Utility Bills by Rate, comparison of each alternative
• Monthly Utility Bills, comparison of each alternative

eQuest File Naming

Topic: Naming eQuest files in a consistent manner to create backups in the course of project development.

• Jobname - Wizard: eQuest project name at the end of the Wizard checklist including custom window and door placement, but before initiating detailed edit mode.
  
• Jobname - Envelope: eQuest project name at the end of envelope detailed edit modifications, including
  
• Addition of walls and windows missing at the end of Wizard edit,
  
• Renaming of spaces, zones and systems and
  
• Assignment of baseline constructions, and
  
• Schedule modifications
  
• The model at this point is ready to begin simulation
  
• Jobname: Working project file name. This file contains the 'moving forward' baseline simulation model.

Note: This is an outline procedure, it will be updated as time permits.

Updating eQuest Utility Rates

Topic: How to keep utility rates current by editing the library file.

• Open the local eQLib.dat file with a text editor
  
• Find utility rate section to be updated, e.g. search for 'PSE', 'SCL' or 'Snohomish'
  
• Note the latest revision date at the beginning of the rate section
  
• Change only the rate needed, e.g. Schedule 36, Schedule 31, Schedule 20 etc.
  
• Add a 'rate changed', 'revised by' and 'date' comments for the latest revision
• BE SURE TO TEST the rate update in an actual simulation!
• If the test passes, run the 'Update eQuest' script to propagate the change
• If the test fails, run the 'Restore eQuest' script and start over
• If the test fails, DO NOT try to repair the library file as it may have been inadvertently damaged. Finding the damage is like finding the proverbial needle in a haystack, so best to limit losses and start over.
• NEVER leave the library file in a broken condition, else it may be propagated to other workstations.

Note: The above link(s) are only valid within the HEI intranet. Firefox users install the "IE Tab Plug-in", then right-click the link and select "Open in IE Tab" from the context menu.