[bldg-sim] LEEDS and GHP's

[Marcus Sheffer]

Is the total cooling load less than 150 tons?  If so there is a LEED CIR 
which allows the use of System 3 in comparison to a GSHP.  This will garner 
you more "savings/points".

If greater than 150 tons you use System 6 with a cooling tower and WSHPs.

You cannot take credit for lowering cooling energy due to a non-regulated 
component such as appliances under EAc1.  The energy use for these items 
must be identical in the proposed and budget models.  Savings in this area 
could be eligible for an innovation point, see the numerous CIRs on this 
subject for more guidance.

At 03:29 PM 2/8/2005, you wrote:
>I humbly request the advice of any/all energy experts that are familiar 
>with LEED and ASHRAE 90.1
>
>We've been asked to perform the energy modeling for a LEED project and 
>could use the experience of the masses to help us past a stumbling block 
>that we've run into.  A little background.  The project is a 4-story major 
>remodeling project that has converted an old office building to new 
>condominiums.  The building is equipped with multiple geothermal heat 
>pumps (1 or 2 per condo) and utilizes a vertical bore ground heat 
>exchanger system for the source/sink for the heat pumps.  After modeling 
>the as-built system in detail using TRNSYS, it is time for us to fill out 
>the energy cost budget report and get the base-building system 
>modeled.  Reviewing ASHRAE 90.1-99 we are directed to Table 11.4.3 (the 
>HVAC Systems Map) that shows the budget system type as System 6; 
>Water-Source Heat Pumps.  The heating system type for this system is 
>listed as "electric heat pumps and boiler".  So far so good, no problems 
>here understanding the intent.  However the cooling type is listed as 
>"direct expansion" with a note that states the fuel type for the budget 
>building system must match the fuel type for the proposed design.  Fair 
>enough, we have geothermal heat pumps providing the cooling so the fuel 
>type for the budget cooling system should then be electricity.  But here 
>we run into the stumbling block.  Typically water-source heat pumps would 
>employ a cooling tower for the heat rejection; is that what is 
>meant/intended - ok forget meant/intended, let's go with "required" - by 
>the standard?  Typically "direct expansion" refers to a chiller; most 
>likely an air-cooled chiller for this application, or sometimes even a 
>PTAC.  However, a base case system that utilizes water source heat pumps 
>and a boiler for heating, and a chiller with fan coils (or a PTAC)  for 
>cooling just doesn't make any sense....
>
>If the guideline is intentionally vague and I have complete flexibility in 
>choosing an electric cooling option for the budget building (within the 
>minimum performance guidelines) does anyone have any recommendations for 
>the "worst" system type for the budget building that will maximize the EA 
>credits and still meet the 90.1 requirements?  We're right on the 
>borderline of LEED Silver and a few percentage points in energy savings 
>can make a big difference in the number of points received.
>
>One last question as long as I still have your attention.  Its our 
>understanding that the building plug loads (non-lighting) are a 
>non-regulated item for LEED and we cannot take direct credit for 
>installing high-efficiency appliances.  However, can the indirect credit 
>of lower cooling energy consumption as a result of lower cooling loads 
>from reduced internal gains be used for the proposed building?  Are we in 
>a gray area here?  And if so, how gray - charcoal?
>
>Thanks in advance for any help that you are able to provide; its been a 
>frustrating couple of days trying to decipher the documents.
>
>Jeff
>
>
>*********************************************************************************
>Thermal Energy System Specialists (TESS)
>Jeff Thornton                                   2916 Marketplace Drive
>Principal                                       Suite 104
>Phone:  (608) 274-2577                  Madison WI 53719
>Fax:  (608) 278-1475                            USA
>E-mail:   thornton at tess-inc.com
>Web Page:       www.tess-inc.com
>
>"Providing software solutions for today's energy engineering projects"
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Marcus B. Sheffer                          energy & environmental consulting
Energy Opportunities, Inc              717-292-2636
1200 E Camping Area Road            Fax: 717-292-0585
Wellsville, PA USA 17365-9783        sheffer at sevengroup.com
a 7group company                        www.sevengroup.com


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