[BLDG-SIM] Energy Cost Budget (ECB) Method & LEED

Christopher Balbach cab at thethomasgroup.com
Mon May 17 11:29:27 PDT 2004


Varkie:

The foreward of the 16 page Addendum E for Std 90.1-2001
(http://www.ashrae.org/template/AssetDetail/assetid/30208)
addresses many of your questions. I would expect LEED 2.2 to reference
this "Informative Appendix G" performance Rating Method when describing
how to use simulation to determine a building's performance rating and
thus capture a number of Energy and Atmosphere points.  

In terms of LCCA, I was at a recent presentation on Std 90 by the
former chair of the committee. My understanding from this presentation
is that results from custom written software (NOT DOE2 or BLAST, I
asked) are used to evaluate the cost effectiveness of proposed changes
to 90.1. A fixed rate for fuel prices and electrical rates was used (for
the entire nation) and the effect on energy consumption of our nations
building stock (dominantly retail and small commercial) was estimated.
As far as differences in "wire to wire" efficiencies between nuclear,
gas, oil, coal, etc) are concerned, despite intense pressure from
industry, Std. 90 does not account for energy consumption using source
efficiency in any appreciable way. 

I'll send you his presentation if you would like (it's 30+ mb, too
large to e-mail).

Thanks,

Chris 




Chris Balbach
HVAC Designer
LEED Accredited Professional
Thomas Associates - Architects and Engineers
(607)-277-7100 ext. 5286

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>>> "Varkie Thomas" <Varkie.Thomas at som.com> 05/17/04 01:27PM >>>
When comparing standard design based on ASHRAE ST90 and a proposed
design for LEED points under "Optimize Energy Performance" using the
ECB
method, can the fuel types in both cases be made the same?  Does STD90
ECB method require natural gas equipment to be used for the standard
design if it produces lower energy costs?  
 
For example, three years ago, gas prices were at a record high and
electricity was relatively cheaper.  So a building was designed based
on
all electric equipment.  The proposed design saved about 30% in energy
usage per year and about the same in cost over the standard design
(electric or gas).  
 
Gas prices have since dropped significantly. The proposed design still
saves about 30% in energy compared to standard design.  The energy
cost
of the proposed all-electric design is now higher if it is compared to
the standard design based on current natural gas rates.  Can the
proposed electric design be compared to the standard model that also
uses all-electric equipment for LEED points? 
 
On page 63, Table 11.4.3A, Budget System Descriptions of ASHRAE
Std90-2001, System-1 is VAV with parallel fan-powered boxes and
electric
resistance heating (electric) and System-2 is VAV standard boxes with
hot water heating using fossil fuel boiler (gas).  If the proposed
design used System-1 (electric) then can the standard be System-1
although System-2 will use less energy and also cost less?
 
In comparing energy costs, does LEED consider the difference in source
energy efficiency between gas and electric?  What about long-term
reliability?  Electricity can be generated using a variety of fuels
including nuclear, whereas natural gas resources are limited and the
costs will therefore increase in the future with diminishing supplies. 

 
Is the purpose of the Energy "Cost" Budget method to reduce the energy
demand based on TOU rates?  Is the comparison between standard and
design for LEED points based on conditions at the time of design or at
the time of occupancy? Does ECB consider future fluctuating gas and
electric rates?  Shouldn't there be a LCCA comparison of energy costs
of
standard and proposed design using the DOE/FEMP future escalation
rates?
 
Is it realistically possible to save over 60% in energy costs over
STD90
design without using renewable energy such as PV-panels and GSHP?
 
Varkie Thomas
Skidmore, Owings & Merrill LLP
Tel: 312-360-4467 (direct)


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