1. Greenbriar East Elementary School Fairfax, Virginia Michelle L. Siano Mechanical Option Spring 2005 Senior Thesis

2. Presentation Outline Project Background Current Mechanical System Redesign Objectives Mechanical Redesign Daylighting Redesign Conclusions Acknowledgements Questions

3. Greenbriar East Elementary School Project Background Location: Fairfax, Virginia Location: Fairfax, Virginia Site: 10 acres surrounded by residential neighborhoods Site: 10 acres surrounded by residential neighborhoods Building Size: Building Size: –59,000 sq. ft. renovation –14,000 sq. ft. addition –Total of 73,000 sq. ft. when complete Dates of Construction: Dates of Construction: –December 2003 - January 2006 Construction Cost: $6.8 million Construction Cost: $6.8 million

4. Project Team Owner Owner –Fairfax County Public Schools Architect/Engineers Architect/Engineers –Hayes, Seay, Mattern and Mattern (HSMM) General Contractor General Contractor –Caldwell and Santmyer, Inc. HSMM

5. Presentation Outline Project Background Current Mechanical System Redesign Objectives Mechanical Redesign Daylighting Redesign Conclusions Acknowledgements Questions

6. Current Mechanical System Classrooms Classrooms –Served by a Dedicated Outdoor Air System (DOAS) with a Parallel Unit Ventilator System –5 100% OA units ranging in size from 1,480 to 2,460 cfm

7. Space Current Mechanical System Non-classroom spaces Non-classroom spaces –Constant Volume System –Served by 7 rooftop units ranging in size from 1,750 to 8,050 cfm –Rooftop units provide full ventilation, heating, and cooling RA OASA RTU

8. Current Mechanical System Evaluation ASHRAE Standard 62-2001 ASHRAE Standard 62-2001 Required – 26,910 cfm Required – 26,910 cfm Designed – 16,110 cfm Designed – 16,110 cfm

9. Presentation Outline Project Background Current Mechanical System Redesign Objectives Mechanical Redesign Daylighting Redesign Conclusions Acknowledgements Questions

10. Redesign Objectives Meet ASHRAE Standard 62 Meet ASHRAE Standard 62 –Removes indoor air pollutants from the space –Results in better health among the occupants Provide humidity control Provide humidity control –Minimizes the potential for bacterial growth –Mold can trigger asthma attacks Asthma has risen 49% since 1982 Asthma has risen 49% since 1982 Use energy efficient equipment to lower operating costs Use energy efficient equipment to lower operating costs

11. Presentation Outline Project Background Current Mechanical System Redesign Objectives Mechanical Redesign Daylighting Redesign Conclusions Acknowledgements Questions

12. Mechanical Redesign Provides ventilation air and meets some of the thermal loads Provides ventilation air and meets some of the thermal loads Benefits Benefits –always meet ventilation requirements due to a lack of mixing –reduces amount of ventilation air –reduces duct and equipment sizes Supply Airflow Comparison Between the Current System and DOAS Unit Current System Supply Airflow (cfm) DOAS Supply Airflow (cfm) RTU-12595279 RTU-280953507 RTU-35160819 RTU-440001133 RTU-51750478 RTU-61840436 RTU-71840431 MAU-116453544 MAU-216503803 MAU-314803307 MAU-422551963 MAU-524603501 TOTAL3477023201 Dedicated Outdoor Air System

13. Mechanical Redesign DOAS Equipment Energy Recovery Units by Semco Energy Recovery Units by Semco –EPHC Model - Enthalpy Wheel plus full heating and cooling 8 units needed of approx. 3000 cfm 8 units needed of approx. 3000 cfm $33,000 - $39,000 $33,000 - $39,000

14. Mechanical Redesign DOAS Equipment Reduction in Coil Sizes Reduction in Coil Sizes 29% Reduction in Cooling Coil 46% Reduction in Heating Coil

15. Mechanical Redesign Parallel System Geothermal Heat Pumps Geothermal Heat Pumps –Dependent on large amounts of water or ground –Utilizes the constant temperature of the ground Results in highly efficient system Results in highly efficient system HP Ground Loop Refrigerant Loop

16. Mechanical Redesign Parallel System Console Units for Classroom spaces Console Units for Classroom spaces –Allows for reuse of current piping for refrigerant loop Horizontal Ceiling units for non-classroom spaces Horizontal Ceiling units for non-classroom spaces –Serve multiple spaces Heat Pump

17. Mechanical Redesign Parallel System Ground Loop Ground Loop –Sized for 55.4 tons of heating vs. 52 tons of cooling –Typical Soil – 200-300 ft/ton Sized based on 250 ft/ton  13,573 ft of ground pipe Sized based on 250 ft/ton  13,573 ft of ground pipe Cost of $750/ton  $41,550 for piping and installation Cost of $750/ton  $41,550 for piping and installation

18. Mechanical Redesign DOAS Savings Chilled Water System Current SystemRedesigned System Unit Capacity (MBH) GPMUnit Capacity (MBH) GPM Make-up Air Units462.092.4 Fan Coil Units111.322.1 Unit Ventilators1157.2230.5 TOTAL1730.5345.0TOTAL00 Hot Water System Current SystemRedesigned System Unit Capacity (MBH) GPMUnit Capacity (MBH) GPM Make-up Air Units679.067.9 Energy Recovery Units754.075.4 Cabinet Heaters258.925.8Cabinet Heaters258.925.8 Unit Heaters101.210.1Unit Heaters101.210.1 Fan Coil Units79.28.5 Unit Ventilators781.580.3 Fin Tube Radiators20.62.0 TOTAL1920.4194.6TOTAL1114.1111.3

19. Mechanical Redesign DOAS Savings Mechanical System Energy Cost Estimates Gas Utilization Gas Cost Electricity Utilization Electric CostTotal Cost Current System1920.4 $ 97,514.071730.5 $ 70,200.50 $ 167,714.57 Redesigned System1114.1 $ 56,571.770 $ - $ 56,571.77 Savings806.3 $ 40,942.301730.5 $ 70,200.50 $ 111,142.80

20. Presentation Outline Project Background Current Mechanical System Redesign Objectives Mechanical Redesign Daylighting Redesign Conclusions Acknowledgements Questions

21. Basis for Evaluation

22. Daylighting Analysis for Current Classroom Average Illuminance Average Illuminance –2.94 fc Maximum Illuminance Maximum Illuminance –41.8 fc Minimum Illuminance Minimum Illuminance –0.3 fc

23. Classroom Redesign Eight 2’ x 3’ windows at 5’ from finished floor Eight 2’ x 3’ windows at 5’ from finished floor

24. Daylighting Analysis for Classroom Redesign Average Illuminance Average Illuminance –12.86 fc Maximum Illuminance Maximum Illuminance –33.5 fc Minimum Illuminance Minimum Illuminance –0.7 fc

25. Presentation Outline Project Background Existing Conditions Current Mechanical System Redesign Objectives Mechanical Redesign Daylighting Redesign Conclusions Acknowledgements Questions

26. Conclusions DOAS DOAS –Reduced Ventilation Quantity by 33% –ERUs utilized enthalpy wheels to reduce heating and cooling loads Geothermal Heat Pumps Geothermal Heat Pumps –Utilize the constant temperature of the ground for heating and cooling Combination Combination –Removes need for chiller –Saves $111,000 in energy use for chilled and hot water systems Daylighting Redesign Daylighting Redesign –Improved average illuminance to 12.86 fc

27. Presentation Outline Project Background Current Mechanical System Redesign Objectives Mechanical Redesign Daylighting Redesign Conclusions Acknowledgements Questions

28. Acknowledgements AE Faculty and Staff AE Faculty and Staff –Dr. Freihaut HSMM HSMM –Mike Kirkpatrick –Cortney Houghland Fairfax County Public Schools Fairfax County Public Schools –Dave Becker My family, James, and friends My family, James, and friends

29. Presentation Outline Project Background Current Mechanical System Redesign Objectives Mechanical Redesign Daylighting Redesign Conclusions Acknowledgements Questions

30. Questions?