CI-2009 EAc1.3: Optimize energy performance - HVAC 5-10 points

This project is to renovate 300,000 square feet of an old factory and convert to a distribution center. The owner strongly desires to be sustainable and will use many sustainable features whether or not LEED certification is sought. We will use high efficiency lighting and high efficiency infrared heaters, but no cooling. If we use the ASHRAE appendix G, we have to model the baseline cooling system for the baseline and the proposed. Since the cooling energy will be much larger than the heating energy the 14% reduction from ASHRAE will not be possible. This force the project to be penalized for energy never actually used. In this case we feel that the ASHRAE standard does not rationally apply. This project will reuse a large facility and incorporate significant sustainability features and we would not like to be excluded because the ASHRAE standard does not apply logically to this facility. Is there any alternative method for compliance in this situation?

The design of an 11,000 square foot library and offices in a new LEED NC building targeted low energy use and superior indoor air quality as two of its most important green building goals. From the beginning of design, our mechanical engineering team has prioritized efficient equipment to meet the E-Benchmark prescriptive criteria for efficiency requirements (EQc1.3 Option A point 1) and EQ credit 5 for high filtration media. We are limited by those requirements to a single proprietary mechanical system of water source heat pumps. As-built conditions in the space revealed that in order to fit our heat pump units in the available head heights, two units serving the Entry Lobby/Children\'s Room and Auditorium needed to be changed to split units. This split effectively reduces the EER and COP standards to slightly lower than the E-Benchmark standards. The total average of system efficiency by capacity remains well above the EER and COP E-Benchmark threshold requirements. These HP-2 split units are sized for a maximum occupancy load that will only occur several times a year in the Lobby and occasionally in the Children\'s Room and Auditorium. As it is not required for LEED-CI, we do not have an energy model to show annual expected use. However, since these split units are sized for a maximum capacity that does not occur regularly, we conclude that the actual average of system efficiency by usage will be much higher than the average by capacity which already meets the threshold. Unit AC-1/ Quantity 1 / Capacity 3 tons / EER=14.0/COP=5.0 Unit AC-2/ Quantity 1 / Capacity 2 tons / EER=18.1/COP=5.7 Unit HP-1/ Quantity 4 / Capacity 10 tons/ EER=16.0/COP=5.0 Unit HP-2/ Quantity 2 / Capacity 8 tons / EER=13.1/COP=4.5 Unit HP-3/ Quantity 1 / Capacity 2 tons / EER=16.5/COP=5.6 Average by capacity: EER=15.25/COP=4.91 E-Benchmark Standard: EER=14.00/COP=4.60 * * 2005 New Building Institute E-Benchmark Standard, Table 2.5.2 Unitary & Applied Heat Pumps, Electrically Operated, p. 69 We propose that we meet the intent of the credit to provide highly efficient HVAC units which meet a high standard, increase our level of energy conservation, and associated environmental impacts.

Our project consists of two small buildings close to the ocean that will achieve substantial energy savings by incorporating a natural ventilation strategy. No mechanical heating or cooling is intended for either building, with the exception of a small electrical/server room. The building is designed with a very narrow and long floor plate situated perpendicular to prevailing winds in the area. Ventilation openings are consistent with the requirements of ASHRAE 62.1-2004 Section 6.8. The project also meets the requirements outlined in the CIBSE Applications Manual 10: 2005 as referenced in EQc2 for Natural ventilation in non-domestic buildings. Per Title-24 2005 requirements for natural ventilation, the sum of operable windows will be greater than 5% of the floor area of each space that is naturally ventilated. The openings will also be readily accessible to the occupants of each space at all times. Outdoor airflow through the openings in regularly occupied spaces will come directly from the outdoors, not through intermediate spaces such as other occupied spaces or corridors. Openings include operable windows, through-the roof ventilators, and vents between interior spaces. Control mechanisms for the natural ventilation openings are manual. A long, tall hallway situated perpendicular to the prevailing winds will collect heated air and exhaust it the outside. The roof over much of the space is sloped allowing air to enter on the low side and exit on the high side. In all cases, the building is designed to facilitate cross-ventilation with windows low on the walls for drawing the air in, and windows and vents high in opposite walls or on the roof to draw air out. Under ASHRAE 55 definitions, the building spaces are defined as "naturally conditioned spaces, occupant controlled" where the thermal conditions of the spaces are regulated primarily by the opening and closing of windows or vents by the occupants. Since the building will have a limited number of occupants most of the time, manual control of the windows and vents has been determined the most appropriate strategy for the building to allow control over individual thermal comfort. As indicated by ASHRAE 55-2004, section 5.3, the occupants of the space will be engaged in near sedentary activities with metabolic rates ranging from 1.0 met to 1.3 met. The mean monthly outdoor temperature for the project is greater than 50 deg. F, and less than 92.3 deg. F all months of the year, as required under ASHRAE 55-2004, section 5.3 for naturally ventilated buildings. The User\'s Manual for ASHRAE 90.1-2004 Appendix G states on page G-21: The proposed building default cooling system does not exclude natural ventilation from consideration. It just means that the proposed building is modeled as a hybrid system where cooling is provided by natural ventilation when conditions are acceptable and by the default mechanical cooling system when natural ventilation is inadequate to provide thermal comfort. We are requesting confirmation that the following modeling strategy conforms to the requirements of ASHRAE 90.1-2004 Appendix G modeling protocol: 1. EnergyPlus will be used to model the building since the EnergyPlus software has the capability to evaluate energy and comfort parameters tied to natural ventilation. 2. The Exceptional Calculation Methodology will be applied to calculate the natural ventilation savings. 3. The Proposed Design model will be developed to reflect the design parameters for the envelope and lighting. Operable windows will be modeled as fixed, and vents will not be included in the model. Mechanical systems will be modeled identically to the default heating, cooling and fan systems in the Baseline case, except that fans in the proposed case will be modeled as cycling on and off to meet heating and cooling loads during all hours in the proposed case, and will operate continuously during occupied hours in the Baseline Case (per the exception shown in Table G3.1.4). 4. Using the Exceptional Calculation Methodology, The Proposed Design case will be modified to include natural ventilation for all hours when the cooling and heating loads can be met. Operable windows and vents will be modeled as designed. Cooling and heating setpoint temperatures will be identical to those in the Baseline Case. Schedules will be adjusted to switch on mechanical cooling during hours when natural ventilation alone cannot meet the space temperature setpoints. The final model will meet the ASHRAE G3.1.2.2 requirements stipulating that the Proposed Design cannot exceed the Baseline Design unmet load hours by more than 50, and that unmet load hours for the Proposed Design and Baseline Design cannot exceed 300. 5. (Plan B) If the hybrid system cannot be manipulated to meet the unmet load hour requirements within the energy model, hourly output data from a natural ventilation model (having no mechanical cooling) and the Proposed Design model will be combined in a spreadsheet. Each hour where cooling and heating setpoints are met in the natural ventilation model, the hourly results for that model will be used. For all other hours, the hourly results from the Proposed Design Model will be used. 6. An Exceptional Calculation Methodology narrative provided with the EAc1 submittal will document any schedule adjustments and assumptions that were made to develop the hybrid system. The savings will also be included as a separate line item on the EAc1 submittal. Is our proposed energy modeling strategy for natural ventilation acceptable?

In the LEED for Commercial Interiors and LEED for Retail: Commercial Interiors rating systems, EA credit 1.3, Option A (for 2.0) or Option 1 (for 2009), Appropriate Zoning and Controls, the credit language states, "Zone tenant fit-out of space to meet the following requirements ... Private offices and specialty occupancies (conference rooms, kitchens, etc.) must have active controls capable of sensing space use and modulating HVAC system in response to space demand". The Interior Design and Construction Reference Guide states that, "requirements need only apply to the extent of the project scope". Does "project scope" refer to all spaces that are within the LEED project boundary, regardless of whether they are included in the scope of work for the project? Must each private office have its own controls, or can private offices be grouped together?

Recently, USGBC approved a CIR regarding savings from key cards in hotel rooms (5/14/07 - see attached). We are requesting that under LEED-NC savings from submetering of multi-family buildings be accepted as an exceptional calculation method. There are no code requirements for submetering of apartment or condominiums in multi-family buildings. Submetering of utilities for individual tenants or owners in multi-family buildings is an added construction cost, but significant energy savings result. Studies have shown that a minimum of 10% energy savings are achieved once individual metering is implemented. Research done by the New York State Energy Research and Development Authority (NYSERDA: http://www.nyserda.org/publications/SubmeterManual.pdf) estimates that installing sub-meters in a master-metered building can reduce building-wide electricity consumption by 10-26%. In Ontario, Canada, non-electrically heated submetered apartments have shown a 16-22% reduction in electricity consumption while electrically heated apartments with submetering showed a reduction in consumption of 30% (http://www.frpo.org/Document/Topics&Issues/UtilitiesEnergy/Options%20to%...). Based on these studies and the fact that submetering is not required by the energy codes, we request that USGBC allow an exceptional calculation method to account for the savings from submetering. We are proposing that 10% cost savings of all submetered end uses be allowed by the calculation method. So, if a living unit is submetered for electricity and gas, the project can assume 10% cost savings for each of these fuel sources based on the energy use within the unit. Energy use in common areas of the building would be excluded from the calculation. Is this acceptable? Related CIR\'s 4/12/2007 - Credit Interpretation Request Per ASHRAE 90.1-1999 and 2004 mandatory requirements, hotel guestrooms must include a master control device at the main room entry that controls all permanently installed luminaires and switched receptacles. We are considering automating this lighting control with the use of a key card-activated master switch. The control would turn off all permanently installed and switched receptacle lighting after the guestroom is unoccupied for more than 30 minutes. The controls may also be configured to allow the interior window shades to be closed automatically when the guestroom is unoccupied. Monitored data for hotel lighting usage patterns is provided in a 1999 Research study by Erik Page and Michael Siminovitch entitled "Lighting Energy Savings in Hotel Guestrooms." This study indicates an average daily usage of nearly 8 hours for the bathroom light, 2 hours for the desk table lamp, 5 hours for the bedside lamp, and 3 hours for a floor lamp. The study also showed that the high use fixtures (the bathroom fixture and bed lamp) did not experience a significant drop during typically unoccupied periods. Instead, these lights were 20% - 25% on during these periods; and the lighting energy consumed during these periods accounted for about 60% of the total guestroom lighting energy consumption. Another study for ACEEE entitled the "Emerging Energy-Savings Technologies and Practices for the Building Sector as of 2004" projects an energy savings for key card lighting controls of 30%. Based on the information provided in these two studies, it seems reasonable to credit hotel guestroom lighting fixtures with a 30% energy savings for automated control based on room occupancy. We propose to model the energy savings achieved through automated control of lighting and interior window shades as an exceptional calculation measure. The lighting savings would be calculated by adjusting the proposed case lighting schedules for all permanently installed and switched receptacle fixtures to 50% lower than the budget case for the percentage of guestrooms modeled as unoccupied. Lighting during all occupied periods will be modeled identically to the budget case. The guestroom lighting energy savings achieved through this measure for the affected lighting fixtures would be 30%. Automated control of the blinds is intended to limit solar heat gains, since the building is in a hot dry climate. The blinds will be modeled identically during the occupied periods as 50% open during daylit hours, and 25% open during evening hours. During unoccupied periods, the shades will be modeled as 25% open. As with all exceptional calculation measures, the savings for this automated control measure will include a narrative documenting the lighting and interior shading schedules and assumptions, and the calculation methodology, and will include a separate line item on the ECB report documenting the savings achieved from this measure. We would like confirmation whether the proposed modeling methodology is acceptable, or direction regarding any modifications that would need to be made to the proposed modeling methodology in order to comply with LEED ECB modeling requirements. 5/14/2007 - Ruling The applicant is requesting confirmation on the proposed strategy for two exceptional calculations. Based on the description of the lighting assumptions, the proposed approach is acceptable. In the LEED submittal please include a narrative documenting the lighting schedules and assumptions and the calculation methodology. Also include a separate line item on the ECB report documenting the savings achieved from this measure. Please provide enough detail in the documentation to allow the review team to ascertain the amount of credit claimed. Based on the description of the automated blinds, the assumptions concerning blind control are insufficient to model the proposed building.

Can we take credit for a demand ventilation system for an automotive service area?Essentially we propose to model the service area in the Baseline Cases at 100% outside air at 1.5 CFM/sq.ft. during occupied periods to meet ASHRAE 62.1. We plan to model the service area in the Proposed Case with typical storage ventilation rate. See rationale below to validate our assumptions.We further propose to model this energy efficiency measure in the standard credit energy models (not as an exceptional calculation) as part of the Baseline and Proposed Cases in order to accurately account for the differences in ventilation load. The differences are based on outside air conditions which change throughout the year and they also impact the supply air unit and fan sizes. The simulation program must size the equipment for the Baseline Case at the peak load and model it use 8760 hours in the year. ASHRAE 62.1 lists a specific minimum ventilation rate for automotive service areas at 1.5 CFM/sq. ft. Ventilation reduction controls are not stated in Ashrae 62.1, nor are they mandated in ASHRAE 90.1-2007. The governing Mechanical Code (International Mechanical Code) optionally permits the use of approved automatic detection devices to control the required ventilation fans and/or make-up air systems. Large make-up air systems providing 100% outside air are still readily available and utilized in order to meet the mandated code. We have utilized the following assumptions for modeling energy usage:Baseline Case - The exhaust ventilation system is modeled to operate at 1.5 CFM/sq.ft. during occupied hours per occupancy schedule. The modeling software automatically sizes the air conditioning system to operate as a 100% outside air system as the total CFM requirement exceeds the design load amount. The unoccupied fan cycle does not include the ventilation and only operates to maintain unoccupied thermostat set point.Proposed Case - The exhaust ventilation system is modeled to be non-operational at any time. We make this assumption based on calculation and witnessed operation at like facilities with the identical control system in place. We have calculated carbon monoxide production based upon maximum estimated daily vehicle round trips through the service area. Eighteen service stalls with an average of 3 vehicles per day and 1 minute round trip drive time yields an estimated total vehicle drive time in the service area to be 54 minutes. The average modern vehicle with catalytic converter produces approximately 150 CFM of exhaust airflow at idle to slow speed containing approximately 1,000 PPM of carbon monoxide. 150 CFM X (0.1%) = 0.15 CFM of carbon monoxide production. The requirement to engage the exhaust ventilation system is 50 PPM of carbon monoxide. The volume of the space is 236,900 cu.ft. and would require 11.845 cu.ft. of carbon monoxide to engage the system. This would require 78.97 minutes of continuous operation without any dilution in a facility this size which exceeds the estimated maximum vehicle operation time of 54 minutes by 30%. The air conditioning equipment serving the area provides 800 CFM outside air and is equivalent to a complete air change twice a day and therefore doubling the daily total required operation time to 157.94 minutes. Operation of vehicles for diagnostic testing is excluded as there is a separate tailpipe extraction system in place to remove all exhaust during testing. Calculations are no substitute for actual conditions. We have interviewed service managers as to the operations of the emergency exhaust system controlled with a CO monitor system. The feed back is overwhelming that the emergency system is never engaged during normal operation. The technicians in these facilities have been trained in the control systems operations and do not desire to have their "conditioned" air purged from the building due to excessive operation of the vehicles within the space.

This project is located on a multi-building medical campus in Illinois. Typical of a campus, it is composed of numerous existing buildings, parking structures, surface lots and circulation streets. The campus is proposing to build, as separately bid projects, a new inpatient building, some additions to existing buildings, and a new parking structure. Our intent is to pursue LEED Certification for the new inpatient building, a new multi-level parking structure and new portions of site work on the campus, but not the additions to existing buildings. One of the buildings included in the project boundary is an open parking structure. The parking structure includes an enclosed combination stair/elevator lobby. We intend to heat this stair/elevator lobby as well as ventilate the space. A telecommunication closet along with an electrical room will be heated and conditioned as well. The parking garage is not required to be ventilated since it is classified as an open parking structure. The parking garage and stair/elevator lobby will have lighting as required. LEED for Multiple Buildings allows a weighted aggregate for the group of buildings based on their conditioned square footage or aggregate PRM calculation. We would like to confirm only the areas being heated and conditioned are required to be included in the square footage calculation for this particular structure when being considered into the overall aggregate or overall PRM. The lighting square footage will take into account the overall square footage being covered by lighting. Please confirm that we are using the correct calculation methodology for this point.

Many space types will not function as regularly-occupied private/individual or multi-occupant spaces, nor will those spaces be utilized for extended periods of time (such as kitchen/break room, meeting room, or conference room). Some unique and smaller (less than 200 SF) programmed space types are infrequently occupied (less than 1 hour) and by only one or a few people at a time. One exception to the credit requirement that "private offices" must have active controls is granted in LEED Interpretation #1645 and clarified in the IDC Reference Guide 2009 Edition, which states that "small private spaces intended for single, temporary occupancy (e.g. for making confidential telephone calls) may be included as part of a larger thermal zone, since changes in occupancy will not cause large swings in the heating and cooling loads." Given the credit intent to reduce energy in occupied spaces and the ruling of LEED Interpretation #1645, we propose to expand the definition for small, temporarily-occupied spaces in two ways: 1. For laboratory buildings/spaces, where loads are typically based on equipment loads, we propose a more specific addition to the definition of Special Occupancy to include spaces that are less than or equal to 200 SF and occupied by two or fewer people for short periods of time. 2. For all project types, we propose an expanded definition of Special Occupancy to include spaces with equal or less than 300 cfm, per ASHRAE 90.1-2007 definition of small zones. ASHRAE 90.1-2007 defines small zones as those with less than 300 cfm, as referenced in Sections 6.3.2.n Criteria, 6.4.3.4.3 Shutoff Damper Controls, and 6.5.2.1.a.4 Simultaneous Heating and Cooling Limitation - Zone Controls. In both of these cases, we propose the space types described above be considered Special Occupancy spaces that may be included as part of a larger thermal zone. Are these definitions acceptable?

The purpose of this CIR is to obtain written confirmation and clarification that the use of TAS 9.0.7 software (by EDSL) can be approved as a energy modeling tool for pursuing EA Credit 1 and EA Pre-requisite 2 After reviewing ASHRAE 90.1-2004 Appendix G section G2, where all requirements are specified, we would confirm that the TAS 9.0.7 computer simulation software tool has the following capabilities: a. 8760 hours per year: TAS is able to simulate on an hourly basis over a total of 8760 year. b. Hourly variations in occupancy, lighting power, miscellaneous equipment power, thermostat set points, and HVAC system operation, deigned separately for each day of the week and holidays: TAS has the capability of adding schedules for all of the above. Different load profile can be created for different times of the day and for different days in the week. The possibility of creating out of hours conditions, nigh time setback temperature, etc. is also available. c. Thermal mass effect: TAS accounts for thermal inertia in the space. d. Ten or more thermal zones: TAS can handle more than ten different thermal zones e. Part-load performance curves for mechanical equipment: TAS is able to simulate part load performance for fans and pumps. TAS can model both constant and variable speed pump systems for primary and secondary. In the air side, different systems can be simulated (i.e. VAV, fancoils, etc) with variation in fan consumption as the load varies. f. Capacity and efficiency correction curves for mechanical heating and cooling equipment: TAS has the capability to incorporate correction curves, even combination of numbers of different types of boilers and chillers within the same project. g. Air-side economizers with integrated control: TAS can incorporate free cooling chillers. It has also the capability to model heat recovery air handling units with by-pass control with an air temperature set point. h. Baseline building design characteristics specified in ASHRAE 90.1-2004 Appendix G section G3: TAS allows the user to build a model for the baseline building using the characteristics specified in G3 and also those in G2.1 (same weather data and same energy rates), although the program does not generate it automatically and it is the user that has to carry out the modeling. 2.0 CIR - Design Energy Builder Energy Plus Modeling Tool Approval Please could you confirm whether the USGBC have approved the use of Design Energy Builder latest Version 2.2 of Energy Plus Software modeling Tool and if this is not the case is the software tool currently accepted by the USGBC.

The purpose of this project is to allow Bank of America employees an opportunity to work closer to home and reduce their commute to the office. One of the features for the plan on this project is the "Focus" Rooms. These rooms allow the people throughout the floor to conduct phone/conference calls confidentially. These spaces are approximately 35 square feet in area. Based on the point for Appropriate Zoning and Controls, it requires private offices, conference rooms and kitchens to have their own controls. Currently, there are 4 of these spaces zoned together on one side of the floor plan. On the other side of the plan, 2 focus rooms are zoned with a wellness room (approx. 62 sf). I am requesting that these focus rooms be excluded from this requirement due to their low airflow requirements and intermittent use. Please clarify if these rooms will be accepted as they are currently zoned.

This project is a major renovation to the existing building envelope (new skin added, new windows) and to the common area part of a tenant occupied office building. We have received approval from the USGBC to use LEED for New Construction. The core space lighting (elevator areas, lobby, restrooms, conference rooms), ductwork and finishes will be modified but the central air handling system and air cooled chiller and the tenant spaces will be only minimally altered. The question has been posed by the building manager regarding if they need to replace the tenant lighting in the space as the tenant space is not in the scope of work for the project. According to the ASHRAE 90.1-2004 users guide, if you were to replace more than 50% of the lighting fixtures in the building, you would have to meet ASHRAE 90.1-2004 lighting requirements, which, based on our analysis of what the base case and current design is in terms of lighting power density for this office building, means the building managers would have to replace all the tenant lighting with T8, 25 Watt lamps. However, if we replace less than 50% of the lighting in the building, we are not dictated by ASHRAE 90.1-2004, unless the renovation increases installed lighting power. However, according to the LEED Reference Guide for the prerequisite EAp2, lighting applies to all lighting installed on the building site including interior and exterior lighting. If the total installed interior lighting power is lower than the interior lighting power allowance calculated using ASHRAE 90.1-2004, the project complies. These two statements contradict each other if there is less than 50% of the lighting replaced, but the LEED Reference Guide does refer to the ASHRAE 90.1 users manual as a reference. Please advise on what to assume for the tenant space lighting power density in both the base case ASHRAE 90.1-2004 compliant building and the design case if less than 50% of the lighting is replaced.

Our project is a newly constructed, 825,751 square foot automotive manufacturing facility in the midwest. The ventilation requirements for our facility, as set forth by ASHRAE 62.1, Section 2.2 states: "Additional requirements for laboratory, industrial, and other spaces may be dictated by workplace and other standards,.". Industrial facilities in this location fall under the requirements of the Michigan Occupational Safety and Health Administration (MIOSHA). Per MIOSHA\'s, health standards ("Part 520. Ventilation Control"), R325.52007 Exhaust ventilation systems, Rule 7 states : "The minimum rate of exhaust ventilation for places of manufacturing, processing, assembling, maintenance and repair, or storage of material shall be 1 cubic foot of air per minute per square foot of floor area. This amount of exhaust ventilation may be provided by local exhaust, general exhaust, or both. The director may permit a variance if contaminant control is accomplished at a lesser rate of ventilation." MIOSHA has stated that an allowable level of contaminant control for dust/mist particulate would be 5 mg/cubic meter. In an attempt to save ongoing heating, cooling and ventilation expenses, the Owner chose to design the new facility in an innovative manner that could attain contaminant control at a much lesser ventilation rate than the default 1 CFM/SF that is set forth by MIOSHA and used by other automotive manufacturing facilities. The manufacturing facility has set a target of 0.5 mg/cubic meter, significantly lower than the MIOSHA required level of contaminant control. In order to reach this high level of contaminant control, they implemented the following innovative approaches: 1 - For the machining and grinding processes, enclosures were constructed and oil mist/dust collection systems were implemented with HEPA filtration. 2 - For the parts washers, enclosures were constructed and local exhaust ventilation systems were designed to capture contaminants at the source. 3 - For processes using hazardous materials, local exhaust ventilation systems were designed to capture contaminants at the source. 4 - "Dry floor guarding" systems have been implemented in the machine tool enclosures in order to minimize any escaping mist from the process. 5 - Micro-bacteria resistant coolants are used in the plant and biocides and utilized and monitored in order to control the bacterial counts in such systems. These control measures are over and above what is done in a typical, newly constructed manufacturing plant. With these control measures being utilized, extensive testing was done through the manufacturing facility to ensure that MIOSHA (and the much more stringent company requirements) exposure limits were being met. During the testing, the facility was ventilated at a rate of 0.21 CFM per square foot. At this ventilation rate, the facility was far below the company\'s target exposure limits, never measuring higher than a 0.13 mg/cubic meter exposure level. The Owner operates their facility at a ventilation rate of 0.5 CFM per square foot. This adds another level of safety factor to the building design. We are proposing that we run the energy model, in both the baseline and proposed case, with a ventilation rate of 1.0 CFM per square foot. We then intend to use the Exceptional Calculation Methodology of ASHRAE 90.1 to quantify our energy cost savings by lowering the ventilation rate. We intend to re-run our "proposed" model with 0.5 CFM per square foot to determine the cost savings for this exceptional calculation.

The project wishes to use Therma-Fusers in private offices to satisfy the intent of LEED CI Eac1.3. Therma-Fusers are supply air diffusers, which are each equipped with an individual thermostat, meaning they have "active controls capable of sensing space demand." However, although the Therma-Fusers do not specifically "modulate the HVAC system in response to space demand," they do satisfy the intent of the credit which is to "achieve increasing levels of energy conservation beyond the prerequisite standard to reduce environmental impacts associated with excessive energy use." Therma-Fusers function at low pressure, which can reduce the horsepower (and therefore reduce the energy demand) necessary to run the fan motor. This fan energy is further reduced because the VAV system serving this particular space incorporates variable speed drives, which allow the system to turn down even further to save more energy. Also, because a typical pressure independent VAV terminal unit can only turn down to 30%, Therma-Fusers save even more fan energy because they can turn down to less than 10% and maintain individual temperature control. Also, because each Therma-Fuser is a zone of control providing individual room control, heating and cooling energy are reduced because no portion of the building is ever over-cooled or over-heated. An independent study has shown 40% energy savings for interior zones and 29% energy savings for perimeter zones when individual room control was compared to multi-room control. Although Therma-Fusers may not save HVAC energy precisely in the manner specified by the credit, we believe, given the energy saving capabilities of incorporating Therma-Fusers within the space mentioned above, their use satisfies the intent of LEED CI EA credit 1.3.

Background: Our project is a 3 story, 16,500-sq.ft. addition to an existing 3 story, 84,000 sq.ft. building. The existing building is predominately laboratory space with some office space. The addition will be of similar use. The heating and cooling of the existing building is served by a central utility plant which provides chilled water and hot water via a steam boiler and heat exchanger. It is proposed that the addition also be served by the central plant. The central plant serves several other buildings on the site as well. In order to make a decision on whether we would like to obtain LEED registration on just the new addition or on the entire building with the new addition, a preliminary building simulation is being modeled. For the ASHRAE baseline, the system is modeled as a "System 3 - PSZ-AC" (packaged rooftop, constant volume, direct expansion, and fossil fuel furnace) per table G3.1.1A of ASHRAE 90.1-2004. Though the combined building size would categorize building with addition as a "System 5 - Packaged VAV w/ Reheat.", section G3.1.1(c) mandates conforming to the requirements of System 3 as an exception due to the special pressurization relationship/ cross-contamination requirement of the laboratory. Interpretation Request: Little is stated in ASHRAE 90.1 2004 on the most appropriate way to model a system that has chilled water and hot water heat supplied from a central plant. However, there are a few CIRs concerning similar circumstance that allude to it such as the 1/27/2004-2/24/2004 EA1.1 CIR. In it, it is stated that "While the situation described is not using purchased chilled water or steam, this HVAC description for the budget building is the closest to the proposed design and should be used for the energy modeling purposes." This approach for the budget building model is quite workable since the building owner has costs available for both chilled water and heating hot water. However, the baseline is modeled as a DX cooling and gas fired furnace. Is it appropriate to model the budget building with chilled water and heating hot water, when the baseline model is using neither of these? If not, how should the baseline and budget building be modeled?

Is there an adjusted point scale and minimum point threshold where applicable for LEED v2009 projects using ASHRAE 90.1-2010?