Case Study -Sandy Grove Middle School First Net Positive Energy P3 School In North Carolina

Transcription

1 Case Study -Sandy Grove Middle School First Net Positive Energy P3 School In North Carolina

2 Public-Private Partnership (P3) Government - provides incentive(s): transfer of asset (land), one time grant, tax breaks / credits Developer obtains incentive(s), obtains financing, designs, builds, may maintain User(s) Leases facility and site, operates and utilizes facility, may be responsible for utility cost and some maintenance

3 Advantages of P3 Delivery Harness expertise and efficiency of private sector Off-balance sheet method of financing the delivery of public sector assets Speed of delivery Possible Tax Credits / Breaks Energy tax credits Potential New Market Tax Credit Eliminates Bid Day Risk Eliminates Construction Risk Reduces Risk of Rate Inflation

4 Public-Private Partnership (P3) Integrated Design, Build, Finance, Operate Solutions Design Build Finance Operate

5 SGMS -Organization / Roles

6 Sandy Grove Middle School Project Team Owner / Developer Design Architect M/E/P Engineers Commissioning Authority General Contractor / CM

7 Sandy Grove Middle School GYMNASIUM STEM School 74,000 SF, designed for 624 students CLASSROOMS SCIENCES High Performance Systems BAND ORCHESTRA ADMIN Ground Source Geothermal CHOIR High Output LED Lighting CLASSROOMS SCIENCES LAB MEDIA CENTER DINING Load Bearing Masonry Enhanced Building Automation and Resource Monitoring Systems ART KITCHEN Solar Photovoltaic (589 kw) CLASSROOMS KITCHEN SCIENCES

8 Other Sustainability Features Enhanced envelope with 6 inches of rigid insulation in roof and 3 inches of spray foam insulation in exterior walls High efficiency plumbing features reduce water consumption by 40% Three electric vehicle charging stations free to User powered by school s solar panels 75% of construction waste was diverted, 20% of construction materials contained recycled content and 30% was produced in the region Furniture is certified green

9 Sandy Grove Middle School Benefits of Leasing School Project delivered (school constructed) in 12 months Energy Positive: Generates 30% - 40% more electricity than it consumes Estimated it will save county approx. $35 million over next 40 years - ($16 million in energy) Designed to LEED Platinum Standards PV and New Market Tax Credits Reduce the total cost of ownership by approximately 70% o Construction, interest and energy

10 Sandy Grove Middle School Life Cycle Cost

11 Sandy Grove Middle School Leasing Energy Positive Schools Energy Positive vs. Traditional Schools

12 Solar Photovoltaic System Local utility is Lumbee River Electrical Cooperative 589 kw PV system is split between two metered systems 504 kw is grid connected and is sell all, electricity feeds the grid and the Owner receives a check from the utility company 85kW PV ties in on building side of second meter; offsetting what is purchased from the grid System oversized to eliminate power bill; since cost is $0.128/kWH and payment is $0.051/kWH

13 Solar Photovoltaic System Solar Panels by REC high performance 250 PE BLK panels 2,310 roof mounted panels can produce 751 MWh annually, 40% more than the school will need Design and installation by PowerSecure Inc. Modules connected in strings (typically eight (8) modules per string), which in turn are collected in combiner boxes for sub arrays. Small weather station on roof tied thru the data acquisition system to the BAS

14 Solar Photovoltaic System Checklists and measurements for Solar PV System Combiner box checks DC voltage, Amperage, Irradiance, ambient temperature DC Megger Test - Ground Inverter installation and start-up For inverters DC input voltage, AC line voltage, comparison between inverter panel readings and field measurements. System operation in kw, summary of PV system output

15 Solar Trees by Spotlight Solar Four trees each 20 ft. tall with 12 solar panels Contribute 12 kw of power Solar design combining clean energy with solar art

16 Stand-by Generator 600kW generator, currently enrolled in demand response program with local utility Automated tie-in under Utility company control to run during peaks 30 minutes to 2 hours Negotiating with utility to employ generator to feed into grid to help during peak demand periods Electrical peak occurs during summer when school is not in session and limited cooling load on the campus.

17 LED Lighting Over 80% of indoor and exterior lighting is LED LEDs use 60% less energy than standard fluorescent fixtures and emit less heat Interior lighting, base specification 3-lamp 32W T8 troffers 90W Interior lighting, upgrading to LED 40W LED troffers Immediate reduction of 56% in energy use Lighting controls included occupancy sensors, schedules and daylighting

18 Geothermal Heat Pump System Geothermal well field with approx. 192 wells, 4½ in diameter, approx. 300 feet deep Primary / secondary pumping systems with VFDs

19 Zone Water Source Heat Pump (WSHP) Zones served by horizontal or vertical WSHP Some with dedicated OA ducts Most equipped with two (2) compressors

20 Water-to-Water Heat Pump for DHW Domestic hot water primary by a water to water heat pump Gas-fired boiler for back-up System equipped with 400 gallon storage tank and recirculating pumps

21 Dedicated Outdoor Air Systems DOAS units with energy recovery wheels and integral controls VFDs and CO 2 sensors control volume of ventilation First stage heating / cooling during low load or unoccupied periods

22 Geothermal Heat Pump System Common Issues Flow TAB contractor proportionally balanced the water for the WSHP and WWHP, but did not do a final balance with all valves open, because there was not a global command from Siemens for this purpose. WSHP had many compressor failures due to inadequate flow once all systems were online. Ground Water Temperature o Design sequences required the loop temperature be kept between 63 F-77 F, yet WSHP/DOAS schedules indicated cooling capacity based on 85 F EWT and heating on 50 F EWT Outside Air Temperature o Delicate balance, OAT may generate a call for cooling when the GWT is too cold for cooling, causing compressor failures

23 Zone Water Source Heat Pumps Common Issues WSHPs and the WWHP were approved as BACnet/IP. Siemens BAS was BACnet/IP as well. However, WSHPs & WWHP arrived on site with BACnet/MSTP. Limited points for Siemens to have dynamic graphics, and control of units. Reprogramming occurred. WSHP integral controls not sourced to BAS. This was preventing the units from going into unoccupied mode. When the WSHP did not go to unoccupied mode, it prevented the geothermal system from going into unoccupied mode. The heating CFM was too low for some WSHP with two compressors. Compressors were going out on high pressure alarm. WSHPs with factory CO 2 controls would not go into unoccupied mode if the CO 2 sensors were enabled by the BMS. The room thermostats provided came with a slider control that allowed +/-5 F from the heating and cooling setpoints. This control could not be overridden from the BMS, so the control setpoints of 74 /70 F became 79 /65 F.

24 Dedicated Outdoor Air Systems Common Issues DOAS units were not controlling temperature based on the demand from the WSHP, as per design. They controlled off their own internal DAT. TAB contractor set water parameters at each DOAS, similar to the WSHP & WWHP, the global command for all units was not performed. DOAS had integrated control system and Siemens was limited to the manufacturer s BAS points. o DOAS and WSHP were not giving BMS a signal to start from the unoccupied mode (CO 2, high humidity, high/low temperature), so they were starting but the geothermal system was not.

25 Lessons Learned Perform conductivity well / loop testing: to ensure the loop will produce the temperatures / tonnage required and that the loop will dissipate heat to the surrounding earth. Conduct a controls meeting prior to the controls submittal. Many interpretations were made by the CC that were incorrect requiring reprogramming. Also need to coordinate multiple subcontractors / suppliers with different automation logic / communication protocols: Modbus, LON, BACnet/IP, BACnet/MSTP Ensure lighting controls and CO 2 sensors are coordinated with the CC submittal. CO 2 ppm need to be monitored and set back when areas are unoccupied during normal hours. Owner / Engineer to ensure that continuous monitoring of BAS system after occupancy is part of the BAS specification. Owner / Engineer ensure the understanding of the building occupancy schedules (normal & holiday) for set back of systems and adherence to energy model.

26 Controls Integration Challenge Siemens Building Automation System - Apogee BAS system - Direct control Geothermal condenser water system - Interface with WSHP, DOAS, Solar PV, Resource Monitoring, Dashboard PV Data Acquisition System Affinity Automation, LLC - Resource monitoring measure and verify utilities - Utilitrend cloud-based energy tracking, trending & reporting tool - Works with meter and automation systems MODBUS, LonWorks and BACnet Lucid Dashboard - Web-based showing building performance and energy usage - Linked to a kiosk in the lobby and smart boards in the classrooms - Shows live performance, as well as historic utility data

27 Lucid Dashboard Tracks building system(s) or submeter(s) and display information (like weather), as frequently as once per minute Enables energy and water reduction competitions Showcases real time system performance and building green features Can be incorporated in interactive wall mounted panels and kiosks, or through the internet.

28 Sandy Grove Middle School 28

29 Awarded ENR Best Project 2013 (K-12 Education Project) Sandy Grove Middle School

30 Thank You!