BUILDING AND PLANT ENERGY ANALYSIS REPORT

Transcription

1 BUILDING AND PLANT ENERGY ANALYSIS REPORT Alicia Carbin Longwood University s New Science Building in Farmville, VA

2 TABLE OF CONTENTS. 1.0 Executive Summary LEED Green Building Certification ASHRAE Std Building Envelope Compliance to ASHRAE Std Lighting Compliance to ASHRAE Std Lost Rentable Space due to Mechanical System Annual Energy Consumption and Emissions Mechanical System First Cost Design Load Estimation Cost Estimates, Life Cycle Analysis, and Operating Costs References.. 18

3 1.0 EXECUTIVE SUMMARY. This report is a plant and energy analysis of Longwood University s New Science Building. The LEED Certification system was discussed, however the building was not rated due to the fact that is not an office building. Even though the building was not rated, it has green building elements including a greenhouse and an energy control system. The science building s roof and glazing were found to comply with ASHRAE Standard 90.1 in regards to envelope compliance, however only half of the wall types comply with the standard. Most of the spaces comply to ASHRAE Standard 90.1 in regards to lighting compliance. The standard values were found using the Space by Space Method and the only spaces which did not comply were the enclosed offices and the corridors. The lost rentable space due to the mechanical system was found to be 2,886 square feet, which is 4% of the total building area. The building HVAC load and energy analysis procedures were discussed in this report. The load analysis was done by Trane Trace 700. The total electrical usage of the building was found to be 2,501,300 kwh in design. This building electrical consumption resulted in chemical emissions of 19,810 lbm of SO 2, 11,556 lbm of NO x, and 3,376,755 lbm of CO 2. A life cycle cost analysis for the building s mechanical system was done by the mechanical engineer for the science building, and was found to be $2,713,431 over the course of 20 years. The total mechanical costs for the science building were determined to be $2,826,619 which is 20% of the total building cost. This value is high compared to normal buildings, but the laboratories are reason for a more energy-intensive and costly building system. Page 1

4 2.0 LEED GREEN BUILDING CERTIFICATION. The U.S. Green Building Council is a national coalition of leaders from across the building industry that work to promote buildings that are environmentally responsible, profitable and healthy places to live and work. Members of the U.S. Green Building Council, representing all segments of the building industry, developed the LEED (Leadership in Energy and Environmental Design) Green Building Rating System. LEED was created to define a green building by a common standard of measurement. LEED raises awareness of green building benefits and has transformed the building market to produce high-performance, sustainable, greener buildings. This system is a voluntary, consensus-based national standard. The 6 major categories of the LEED Green Building Certification Rating System are: Sustainable Sites, Water Efficiency, Energy and Atmosphere, Materials and Resources, Indoor Environmental Quality, and LEED Innovation Credits. The four levels of certification that a building design could obtain are: LEED Certified (26-32 points), Silver (33-38 points), Gold (39-51 points), and Platinum (52+ points). Overall, the LEED certification for Longwood University s Science Building was not applicable due to the fact that it is not an office building. There are a few elements of the building design that add to the greenness of the building. A major green element of the science building is the greenhouse on the south end of the 4 th floor. Another energy friendly element in the design is a DDC energy management and temperature control system with pneumatic actuators for large dampers and valves. It is manufactured by an open protocol temperature control manufacturer and is Lonmark compatible. This control system is provided for the HVAC system of the science building. Page 2

5 3.0 ASHRAE STD ASHRAE Standard 90.1 provides guidelines on economical design, construction, and operation of systems. It gives building design data and information to help maintain and operate healthy indoor environments in buildings. The two sections of the standard that will be covered in this report are section 5: Building Envelope and section 9: Lighting. The compliance of the building envelope and lighting of Longwood University s New Science Building are discussed in the following sections of this report. The science building is located in Farmville, VA. The closest location included in ASHRAE Standard 90.1 is Lynchburg, VA. Table D-1 of ASHRAE Std gives the weather data for Lynchburg, VA where the cooling design is at 90db/74wb, and heating design at 12db. 3.1 BUILDING ENVELOPE COMPLIANCE TO ASHRAE STD The building materials of the science building were found on the architectural drawings. The building was found to have four typical types of exterior walls, each with its own R-value. The R-value of the roof was also found. These R-values were found using the ASHRAE Fundamentals Handbook as well as various Internet sources. After the individual R-values for each material was found, they were added up to find a total R value for each wall. The U-value of the wall was found by the following equation: U-value = 1. (R-values) Page 3

6 The following are typical exterior wall sections of the science building: (a) (b) (c) (a) Brick wall section (c) Pre-cast Pilaster wall section (d) (b) Concrete, CMU, and Brick wall section (d) Metal closure section Page 4

7 The U-Values of the exterior walls were calculated as follows: Wall Type Material R-Value Brick Wall Outside surface, 15 mph wind Brick Veneer 0.44 Air gap # Felt /8 Exterior Sheathing Metal Studs, 16 O.C Batt Insulation 13.0 Inside surface, still air 0.68 Total R-Value: Total U-Value: Concrete, CMU, and Brick Wall Outside surface, 15 mph wind Brick Veneer CMU 0.80 Air gap 0.06 Bituminous damp proofing 0.56 Cast-in-place concrete 0.64 Inside surface, still air 0.68 Total R-Value: 3.31 Total U-Value: Pre-Cast Pilaster Wall Outside surface, 15 mph wind 0.17 Type P4 Pre-cast Pilaster 0.64 Air gap # Felt /8 Exterior Sheathing ½ Metal Studs, 16 O.C 0.60 Batt Insulation 13.0 Inside surface, still air 0.68 Total R-Value: Total U-Value: Metal Closure Wall Outside surface, 15 mph wind 0.17 Pre-finished Alum Curtain wall Layers of 5/8 Gyp. Bd Metal Studs 1.20 Inside surface, still air 0.68 Total R-Value: 5.95 Total U-Value: Page 5

8 The U-value is a measure of the heat transfer characteristics of an assembly of materials. The lower the U-value number, the greater the heat transfer resistance (insulating) characteristics of the wall. The wall with the lowest U-value (0.058) was found to be the Brick wall. Therefore, the brick wall has the highest insulating characteristics in the science building. The wall with the highest U-value (0.302) was found to be the exterior wall made of concrete, CMU, and brick. Therefore, this wall was found to have the lowest insulating characteristics in the science building. The roof with a U-value of was found to have high insulating characteristics. Below is a typical section and calculated U-value of the roof: Type Material R-Value Roof Outside surface, 15 mph wind Ply Built up Roofing w/ Bitumen R20 Rigid Roof Insulation Concrete Slab 0.64 Metal Deck 0.00 Horizontal Inside surface, still air 0.61 Total R-Value: Total U-Value: The Building Envelope Requirements of Table B-n of ASHRAE Standard 90.1, were used to determine if the calculated U-values of the science building would comply to the standard. To decide which B-n table is needed, the Heating Design Day and Cooling Page 6

9 Design Day values were found for Lynchburg, VA in table D-1 of ASHRAE Standard It was found that the HDD65=4,340 and the CDD50=3,728. These values refer us to Table B-13 of the standard. Table B-13 sets forth maximum U-values for non-residential buildings for wall assemblies. It was found that the walls which would be classified as Steel Framed as well as the roof classified as Insulation Entirely above Deck comply with ASHRAE Standard 90.1 in regards to envelope compliance. The walls which would be classified as Other did not comply with ASHRAE Standard 90.1 in regards to envelope compliance. To summarize, the envelope types with high insulation characteristics complied with the standard, and those with lower insulation characteristics did not comply. The following table shows the calculated U-values compared to the U- values required by the standard: Type Calculated U-values ASHRAE Std Maximum U-Value (from Table B-13) Comply to ASHRAE Std. 90? Brick Wall Yes Concrete, CMU, and Brick Wall No Pre-Cast Pilaster Wall Yes Metal Closure Wall No Roof Yes The SHGC of the science building glazing was found using the 2001 ASHRAE Fundamentals Handbook. Assuming the windows are insulating glass on extruded aluminum frames, the SHGC=0.34. Using Table B-13, the required SHGC by the standard is 0.49 for 15% glazing. Therefore, it can be concluded that the glazing of the science building complies with ASHRAE Standard90.1 in regards to envelope compliance. Page 7

10 3.2 LIGHTING COMPLIANCE TO ASHRAE STD The Space by Space Method from section of ASHRAE Standard 90 was used to determine the interior lighting power allowance of Longwood University s Science Building. These allowable values were then compared to the lighting power taken off of the lighting fixture schedule used in design. The Space by Space Method requires the use of Table for which the building type as well as space type needs to be known. The science building falls under the building type School/University. The space types used were: enclosed offices, classroom/lecture, lounge/recreation, restrooms, corridor/ transition, active storage, and electrical/mechanical. The floor areas of each of the spaces also need to be known to use this method. The floor areas were then multiplied by the allowed lighting power density from Table to give the lighting power allowance for each space. When the values are compared, it is found that all spaces were compliant with the standard with the exception of the office and the corridors. The office was very close to compliance, and the corridors were probably designed to have more light because of the large amount of occupants the building holds. Specific Room (typ. for space type) Space Type Floor Area (ft 2 ) Lighting Power Density (W/ft 2 ) Design Lighting Power for the Space (W) Allowable by ASHRAE Lighting Lighting Power Power for the Density (W/ft 2 Space (W) ) Comply to ASHRAE Std. 90? Room 324 Enclosed Office No Room 103 Classroom/ Lecture Yes Room 100 Lounge/Recreation Yes Room 124 Restrooms Yes Room 114 Corridors/Transition No Room 116 Active Storage Yes Room 113 Electrical/Mechanical Yes Lighting Compliance Results Page 8

11 4.0 LOST RENTABLE SPACE DUE TO MECHANICAL SYSTEM.. The total building area is 71,800 square feet, and the lost rentable space due to the mechanical system was found to be 2,886 square feet. This lost space is 4% of the total building area. The following is a detailed break down of the lost rentable space caused by the mechanical system of Longwood University s New Science Building. Floor Type of Space Total Area 1st Mechanical Room 113 2,100 2nd Main Mechanical Chase 133 Vertical Shafts 150 3rd Main Mechanical Chase 133 Vertical Shafts 87 4th Main Mechanical Chase 133 Vertical Shafts 150 Total Area Lost = 2,886 sf` Lost Rentable Space due to Mechanical System. 5.0 ANNUAL ENERGY CONSUMPTION AND EMISSIONS SUMMARY. The electricity consumption for educational facilities was obtained from the 1999 Electrical Consumption and Expenditure Intensities (Table C10) on the Department of Energy website. Assuming that the Longwood Science building fits into the educational facility category, it was found that the building consumes 8.7 kwh per square foot of energy. Since the science building is approximately 71,800 square feet, the energy consumed by the science building is 624,660 kwh. However, this value is not a good enough estimate because even though the science building is an educational facility, it requires more kwh than an average educational facility due to the fact that it has more Page 9

12 electrical equipment, including laboratory equipment and many computers. For this reason, it was found that a better estimate for the electrical consumption of the science building would be something with a higher rate, so the floor space category rate was used from Table C10. It was found that the building consumes 14.4 kwh per square feet, considering that the building falls into the 50, ,000 square feet range. This rate gives us a higher approximation for the building electricity consumption of 1,033,920 kwh. When this number is compared to the design kwh of electricity consumption, it was still found to be a low estimate. The value used in design was 2,501,300 kwh. This designed value was calculated by the Trane Trace 700 program and is considered to be fairly accurate. The reasons that the electrical consumption rates in Table C10 of the 1999 Electrical Consumption and Expenditure Intensities were not accurate enough were because it does not list values for this specific building type. The science building consumes much more electricity that an average educational facility, as well as more than an average facility in the same building floor space category or any other category in the table. The total energy consumption by fuel type for the state of Virginia was obtained from the 2000 data provided on the Energy Information Administration website. Table 7 was used to obtain the amount of coal, nuclear power, and hydroelectric power that produces electricity per year. Table 12 was used to obtain the amount of natural gas that produces electricity per year. It was assumed that petroleum (Oil) does not produce any electricity. The total amount of electricity produced was found, and the % Energy Mix of each fuel type was calculated. The table on the following page shows the breakdown of the emissions associated with the on-site electricity produced by the fuels. Page 10

13 Fuel % Energy Mix lbm Pollutant j Particulates SO 2 /kwh NO x /kwh CO 2 /kwh Coal E E E E+00 Oil E E E E+00 Nat. Gas E E E E-02 Nuclear E E E E+00 Hydro/Wind E E E E+00 Totals E E E E+00 Breakdown of Emissions Associated with On-Site Electricity Use in Virginia Approximate amounts of sulfur dioxide (SO 2 ), NO x, and carbon dioxide (CO 2 ) produced by Longwood University s Science Building electrical usage were determined from the rates provided by the Energy Information Administration s Estimated Emission Associated with Onsite Electrical Usage calculations. It was found that no particulates are generated from oil, natural gas, nuclear power, or hydroelectricity. The total emitted SO 2 pollutants were 7.92E-03 lbm/kwh. The total emitted NO x pollutants were 4.62E-03 lbm/kwh. The total emitted CO 2 pollutants were 1.35 lbm/kwh. Since 2,501,300 kwh of energy was found to be consumed by the science building, the pounds of mass of the pollutants is able to be calculated. The results are: 19,810 lbm of SO 2, 11,556 lbm of NO x, and 3,376,755 lbm of CO 2 produced by Longwood University s Science building electrical usage. In a study done by the University of California, through the U.S. Department of Energy, it was found that laboratorytype facilities are much more energy-intensive than typical buildings in California, as illustrated in Figures 2a. This conclusion is a major assumption of this report as well. Page 11

14 6.0 MECHANICAL SYSTEM FIRST COST. The final estimate for Longwood University s New Science Building was computed by the estimating company Project Cost, Inc. The detailed report breaks up the cost into major building systems, which include: Foundations Slab on Grade Structural Frame Supported Floor Roof Structure Roofing, Stairs Elevators Exterior Walls Interior Walls Interior Finishes Doors and Hardware Windows & Glazed Walls Specialties Plumbing HVAC System Fire Protection Power Lighting Special Electrical Special Systems/Equip. For the final estimate they also include additional costs for: General Conditions (8%) Bonds and Insurance (1.5%) Overhead & Fee (5%) Escalation (4%) Design Contingency (2.5%) The Mechanical system is broken down into Plumbing, the HVAC system, and the Fire Protection system. The total mechanical system first cost, as well as the cost per square foot is summarized as follows: System Total Cost Cost per sf Plumbing $219,406 $3.10/sf HVAC $2,442,913 $34.49/sf Fire Protection $164,300 $2.32/sf Total Mechanical System $2,826,619 $39.91 Mechanical System First Cost Summary Page 12

15 The total mechanical system cost of $2,826,619. This amounted to 20% of the total building cost which was $14,084,660. According to RS Means Mechanical cost data, the mechanical cost percentage should be between 4.10% and 12% of the total building cost. The reason the percentage of mechanical cost is so high for the science building is because the mechanical system is much more complex than that of a typical building. The science building requires 100% outside air for many of the laboratory spaces, as well as hood exhaust. For these reasons, there is much more ductwork in this building than a typical building, and it requires additional equipment that increase the costs of the system as well. 7.0 DESIGN LOAD ESTIMATION. The load design estimation was determined using Trane Trace 700. There were many assumptions used to perform the analysis, which included: Lighting loads were determined using ASHRAE Standard 90.1 (W/sf) Equipment loads were estimated using manufacturer s data (W/sf) The weather data was based on Roanoke, VA The space cooling and heating were chosen to be 78F db and 70F db, respectively The relative humidity chosen for thermal comfort was chosen to be 45% Other factors that were taken into account in the analysis were: Room areas and occupancy from design documents Floor to floor and plenum heights Dimensions and orientation of exterior walls Room cooling and heating airflows Envelope materials and U-values Location of room with respect to conditioned or unconditioned spaces All system types were chosen to be Series Fan-Powered VAV Air handling units Page 13

16 The design cooling load was calculated in Trane Trace 700, and yielded the following results: System Cooling Capacity (MBh) Supply Airflow (cfm) Ventilation Airflow (cfm) Percent OA Tons of Cooling Floor Area Supplied by System Cooling (ft^2/ton) Supply Ventilation (cfm/ft^2) (cfm/ft^2) AHU-1 1, ,541 10,624 43% , AHU-2 1, ,091 15, % , AHU-3 1, ,829 26, % , AHU ,321 1, % 8.9 1, The following is the breakdown of cooling peak load: Cooling Peak Loads Btu/hr Envelope Loads 269,165 Lighting Load 168,165 Occupant Load 144,900 Misc. Load 83,097 Ventilation Load 518,331 Supply Fan Heat 85,685 Return Fan Heat 29,967 Supply Fan Heat, 6% Ventilation Load, 41% Return Fan Heat, 2% Misc. Load, 6% Envelope Loads, 21% Lighting Load, 13% Occupant Load, 11% Page 14

17 8.0 COST ESTIMATES, LIFE CYCLE ANALYSIS, AND OPERATING COSTS The initial capitol cost estimate is not a complete cost estimate, only a comparison between different rooftop air handling units and their accessories. The cost estimates were derived from Manufacturer s Data as well as the 2001 RS Means Mechanical Cost Data. The following data shows the breakdown of data used to find this value: Description Unit Cost Cost Material Labor Material Labor Total Cost Chillers CH-1, CH-2 $49000 $8700 $98000 $17400 $ OH & P $44541 $12044 $56585 Sub Totals $ $29444 $ (Including Contractor OH & P) Totals with 4.5% Escalation $ $30769 $ Cost Estimate for New Construction of Chillers The engineers that designed the science building performed a life cycle energy analysis on the building. The assumptions for their analysis are as follows: Energy consumption based on Trane Trace 700 Program. Economic Analysis based on a building HVAC system life of 20 years per 1999 ASHRAE HVAC Applications Handbook. The efficiencies for the chillers used are based on values from Trane: kw/ton. The efficiency of the run around loop heat recovery system is assumed at 65% as an economical value. The cost estimates for the life cost analysis are based on a differential cost comparison between HVAC system alternatives with different system components. They are not complete cost estimates for each HVAC system alternative. The life cycle analysis performed by the engineers was broken into: replacement cost, fuel/energy cost, Page 15

18 operating cost, maintenance and repair cost, and the salvage value. No replacement cost was used in the life cycle cost analysis because the life cycle study period equals the expected life of the mechanical equipment. The maintenance cost was derived from 1999 ASHRAE Applications Handbook Estimating Maintenance Costs. For the base system with screw compressor chillers: ( *[number of years] ) * 71,800 ft 2 /100 = $24,313 Year 1+ $ each Years No mechanical equipment had any salvage value based on a 20-year system life. Electric consumption cost includes Basic Customer Charge, Power Supply Demand Charge, Distribution Demand Charge, Energy Charge, and Ratchet Charge. The electrical cost rate for Virginia Electric Power Company, which supplies Longwood University, was found to be 6.23 cents/kwh in Virginia on the Utility Retail Sales Statistics table from the Department of Energy website. The gas cost rate was found to be $0.19/square foot for an educational facility greater than 50,000 square feet. The estimated electrical operational cost of the science building was found to be $155,830 and the estimated gas operational cost was found to be $13,640 using the following calculations: Electrical operational cost = 6.23 cents/kwh x 2,501,300 kwh x ($1/100 cents) = $155,830 Gas operational cost = $0.19/square foot x 71,800 square feet = $13,640 The water rate used for Longwood University is $14.30 for first 3,000 gallons + $2.20/1000 gallon for additional gallons. This rate would be used to determine the operational cost for water usage, if the amount of water is known. Page 16

19 The life cycle energy analysis (over 20 years) is summarized in the following table: Year Initial Capitol Cost Estimate Escalation Rates 4% 4% 4% 4% 4% Replacement Cost Fuel/ Energy Cost Operating Cost (Steam) Maint. & Repair Cost. Salvage Value Total Escalated Cost Present Worth Discount Factor at 6% Per Annum Total Present Value 1 $ Total Present Value Life Cycle Cost: $2,713,431 Page 17

20 9.0 REFERENCES ASHRAE Fundamentals Handbook. I-P Edition. ASHRAE Standard Energy Standard for Buildings Except Low-Rise Residential Buildings. IP Edition Commercial Buildings Energy Consumption Survey Detailed Tables. Table C10, Electricity Consumption and Expenditure Intensities, Energy Efficiency in California Laboratory-Type Facilities. Report done by the University of California, through the U.S. Department of Energy. July 31, Green Building Rating System for New Construction & Major Renovations. (LEED- NC). Version 2.1 November 2002, revised 3/14/03. Leadership in Energy and Environmental Design online: Project Cost, Inc: Estimate of Probably Construction Cost Final Estimate for Longwood University s New Science Building. Prepared by: John Billings. February 6, U.S. Green Building Council online: Colorado Energy Online. R-value tables. Page 18