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New Gorham Elementary School Project
Information on
Geothermal Heat
Whitney Engineering, P.A.
10 Danforth Street
Portland, Me. 04101
(207) 874-7449
Date: September 7, 2008
To: Lyndon Keck, PDT Architects
The letter to Governor's office indicates that annual energy use calculations are biased in favor of geothermal Gorham Middle School (GMS) vs. non-geothermal High Performance Schools (HPS). The bias comes from ignoring electrical inefficiency value in energy use calculations and aggravated by dominance of electrical use with geothermal heat pumps in a geothermal HVAC system. Consequentially, the Portland Press Herald article 7/24/08 report of a 38% reduction in energy use by a geothermal school (Gorham Middle School) misleads readers; and worse still, misleads residents to vote in favor of $700,000 to fund a geothermal system for a proposed school.
The letter offers the following authorities as the basis for use of electricity inefficiency value:
1) (U.S.) Department of Energy (DOE)
2) (U.S.) Department of Environmental Protection (EPA)
3) ENERGY STAR
4) Massachusetts Technology Collaborative for High Performance Schools
A review of publications by these agencies on internet sites reveals that ENERGY STAR is the driver of energy evaluations based on electrical inefficiency value and uses EPA as a reference source. So what is the basis of ENERGY STARÃs assertions concerning building energy consumption that appeared in the letter? Should electrical inefficiency be applied to energy use comparison between Gorham Middle SchoolÃs (GMS) geothermal system vs. (proposed) High Performance Schools (HPS)? ENERGY STAR's answer is Source-Site Ratios should be used for comparative energy evaluations of any building nationally. This then raises further questions: what are source-site ratios and should they be used.
Source-Site Ratios: ENERGY STAR defines source energy as derived from raw fuel and site energy as fuel consumed by the specific building site. Note that the latter is the basis for fuel billings to the owner. In definitions of source-site, EPA has joined ENERGY STAR in this effort, but it should be noted that DOE has not.
However, the U.S. Energy Information Administration (EIA), a department of DOE, recognizes that source energy information is useful to policymakers and energy analysts concerned with broader energy or environmental issues. On the other hand, DOE states that site energy data are most useful to building engineers, energy managers, building owners, and others concerned with consumption directly related to the buildings end use equipment. (And architects should be added).
Moreover, reflecting EIA/DOE's definition, the following authorities do not recommend use of source-site electrical inefficiency values in energy conservation evaluations as proposed by ENERGY STAR:
1. Massachusetts Technology Collaborative for High performance Schools (even though referenced above as promoting source values))
2. U.S. Green Building Council (USGBC) LEED Certification procedure.
3. ASHRAE 90.1
4. Energy simulation programs such as TRANE Trace T700, DOE-2, e-QUEST
5. Maine Bureau of General Services (especially including previous BPI) energy evaluation requirements.
All these agencies recommend use of site, not source, energy values.
It is noted that by using ENERGY STARÃs source values for comparative energy efficiency of Maine schools, all building types (office, education, hospital, filling station), % of fuel mixed, geographical location (climate variables), occupancy, use, operation and maintenance of the building are eliminated from comparative energy use evaluation. What then to make of the explicit reference to electrical inefficiency for comparative energy evaluation between Gorham Middle School (GMS) and High Performance Schools mentioned in the letter?
Electrical Inefficiency: If site energy is used, then Gorham Middle School's site energy value of electricity is calculated using '100% efficient' electricity, whereas the value is 33% electrical efficient electricity if source electricity is utilized in comparative calculations. Applying source electrical efficiency values, Gorham Middle SchoolÃs electrical energy use for geothermal should be 3-times more and consequently diminish both energy performance and cost savings for GMS geothermal compared to HPS non-geothermal HVAC systems. Nevertheless, is there a reasonable argument for using source energy values for comparative energy evaluations rather than site values?
No. 2 Fuel Oil vs. Electricity: Gorham Middle School (GMS) does not use No. 2 fuel oil for its HVAC system (but does use natural gas for kitchen appliances and for domestic hot water). Moreover, comparative High Performance Schools (HPS) are likely to use No. 2 fuel oil and possibly natural gas if in proximity to a natural gas supply and distribution source. It is noted that energy calculations in the letter to the GovernorÃs Office do not mention the source energy value of No. 2 fuel oil.
EPA/Energy StarÃs No. 2 Fuel Oil Energy Efficiency Rating: EPA does not rate No. 2 fuel oil for source energy efficiency. ENERGY STARÃs efficiency rating For No. 2 fuel oil is based on a single study at one national location-CaliforniaÃs highway vehicle diesel fuel energy use based on BTU/mile units. The default assumption by ENERGY STAR is production and distribution of highway diesel fuel in California is analogous to No. 2 fuel oil energy use by a High Performance School in Maine.
From this, it is reasonable to conclude that applying 33% energy efficiency to electricity and nearly 100% to No. 2 fuel oil needs more effort in source energy documentation (and other EPA/ENERGY STAR fuels such as wood as well). This would result in more realistic energy use comparisons between geothermal to non-geothermal schools of source values are to be used.
Finally, EPA's official stance is they do not produce an annual report that quantifies losses associated with fuel oil distribution, storage and dispensing. Result: High Performance Schools (HPS) consuming No. 2 fuel oil are given a free ride in geothermal (GMS) vs. non-geothermal comparisons (HPS) after banging geothermal schools for being inefficient electricity hogs. This gives a very different flavor to claims in the Governor's letter that existing Maine Department of Education geothermal evaluations result in incorrect statements in the press (38% savings)or mislead residents and voters. Would it reasonable to expect Maine residents to accept the comparison that No. 2 fuel oil High Performance Schools in Maine have the same 99% source efficiency as highway diesel vehicles in California?
Recommendations:
1. Continue using Gorham Middle School's (GMS) annual energy use in BTU/sq. ft. based on actual building's (site) electrical and natural gas fuel use billing in dollars (for kitchen and domestic hot water) for comparison with energy use for High Performance Schools (HPS). This means that electrical efficiency factor for energy school use calculations continue as 100%, not 33%.
2. Accept as reasonable, the Portland Press Herald's article statement of 38% energy savings for 5-year old Gorham Middle School compared to prospective non-geothermal schools and based on Combined Energies conclusions in their 2006 independent evaluation of geothermal HVAC systems report. This would include assurance that residents and voters are not misled in voting in favor of additional cost for a geothermal field.
3. Discard EPA/ENERGY use of source-site ratios for energy sources and continue to implements site energy values for fuels per EIA/DOE, USGBS, ASHRAE, BGS, various energy evaluation programs (and even the Massachusetts Technology Collaborative for High performance Schools).
Finally, it is believed that the letter to the governor does raise a valid issue for anyone engaged in energy conservation for schools, particularly geothermal applications. This is especially true if prudent calculation methods are required to communicate with ordinary citizens who are likely to have more appreciation of energy use costs than the definition of a BTU per square foot (and especially BTU/mile for diesel highway vehicles).
Regards,
Whitney Engineering, P.A.
Richard P. Whitney, P.E
REFERENCES:
1) State of Maine Department of Education letter to Anthony J. Lisa, Jr. P.E dated August 18, 2009
2) Anthony J. Lisa, Jr. P.E. letter to Office of Governor not dated
3) Gorham Middle School Independent Evaluation of Geothermal HVAC System, Richard G. Doughty, PE,
Combined Energies, Augusta, Maine dated November 21, 2006 (Note: HVAC is Heating, Ventilating and Air Conditioning)
4) Energy Star Performance Ratings Methodology for Incorporating Source Energy Use, December 2007
5) Massachusetts Technology Collaborative for High Performance Schools, ìMassachusetts High
Performance Schools Guidelines: Criteriaî, October 16, 2006, v 1.0, Page 53 of 138
6) State of Maine, Life Cycle Analysis, Public Improvements Including Public School Projects, July 1977 (Revised ñ May 1984), Reprinted Nov 1999
7) eia.doe.gov/eneu/consumptionbriefs/cbecs/cbes_trend/primary_site.html
file: Response to PDT Letter 09-15-08
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