ASHRAE Level I Energy Audit June 2011

Transcription

1 Knight Law Center Eugene, Oregon ASHRAE Level I Energy Audit June 2011 Prepared for University of Oregon by, PORTLAND SACRAMENTO HOUSTON ORLANDO 421 SW Sixth Ave Suite 200 Portland, OR nd Street Suite 200 Sacramento, CA Bissonett Suite 408 Bellaire, TX Lake Avenue Orlando, FL 32803

2 TABLE OF CONTENTS Summary 3 Systems Narrative... 3 Energy Use Analysis 6 Energy Audit Procedure and Results.. 8 Appendices.. 22

3 SUMMARY The William W. Knight Law Center is a four story educational building and home of the University Of Oregon School Of Law. Constructed in 1999, it has approximately 147,450 square feet of gross floor space that includes eight classrooms, a 200-seat auditorium, three meeting rooms, eighty-seven offices, one moot courtroom, eight group study rooms, and ten individual study rooms. The site includes landscaping around the building, sidewalks and a small surface parking lot. To improve the buildings energy performance, at least to the level of the LEED Existing Buildings: Maintenance & Operations prerequisite requirement of an ENERGY STAR rating of 69, it must reduce its annual site energy consumption by approximately 9% or 1.1 million kbtu/year. Some of the more aggressive energy efficiency measures (EEM) needed to accomplish this reduction include: Retrocommissioning Installation of split A/C system for the main server room VFD drives and 2 way valves on the CHW & HHW distribution systems Lighting upgrades As there are a number of EEM s that address lighting which may not be practical to implement in some cases, it s recommended that the services of a lighting specialist be pursued to further evaluate all lighting options. This report prepared by Green Building Services meets the requirement of an ASHRAE Level I energy audit of the Knight Law Center. SYSTEMS NARRATIVE Air Distribution and Ventilation Systems: The Knight Law Center uses a VAV air distribution system supplied by four primary air handlers with economizers, AHU-1 through AHU-4. Air handlers are located in the third floor attic and on the fourth floor roof. Air handler supply and return fans are all controlled by 3 ASHRAE Level One Energy Audit

4 variable frequency drives. Air is provided to building spaces through approximately 129 VAV distribution boxes. Each VAV box is protected by 2 thick disposable air filters. Outside air ventilation is provided by each air handler and by operable windows throughout the building. Currently there are no controls or devices to communicate to the building occupants when it s appropriate to open windows. Cooling Systems: Cooling is provided by chilled water from the UO campus central plant. Chilled water enters the building through the steam tunnel in the basement and feeds a chilled water loop that supplies AHU-1 through AHU-4. Two constant speed 7.5 HP Bell & Gossett pumps circulate this chilled water throughout the building. Additional cooling for a network switching room on the second floor is provided by a Mitsubishi Mr. Slim mini-split heat pump. The main server room also on the second floor is currently conditioned by the central VAV system. Heating Systems: The VAV system uses hot water reheat coils at the supply boxes as the primary means of heating the building. The hot water loop is powered by steam from the campus central plant. Steam lines enter the basement via steam tunnels and heat a hot water loop in a concentric tube heat exchanger. The hot water loop is circulated to VAV supply boxes throughout the building by two constant speed 5 HP Bell & Gossett circulator pumps. Building HVAC Controls: The building automation system used to control the HVAC systems is a direct digital control Siemens Apogee system. There are approximately 130 zones. Building operating hours are normally 7 a.m. to 12 a.m. Sunday through Thursday, and 7 a.m. to 10 p.m. Friday and Saturday. Occasionally the building operates 24 hours a day during finals week and other periods of high student occupancy and activity. 4 ASHRAE Level One Energy Audit

5 The building s controls are split into two zones, north and south sections divided by the atrium. The heating hot water (HHW) set point is based on building load or AHU demand. The HHW circulating pumps are scheduled off during unoccupied periods. The chilled water circulating pumps operate around the clock to support the building s main server room. Typical room average temperature set point is 70 F. There is currently no night time cooling set back and the night heating set back point varies based on outside air temperature. A morning warm-up as well as a night flush out procedure is programmed into the BAS. Domestic Hot Water System: Service hot water is supplied by a steam-to-water storage heater located in the basement. The water heater has a maximum input of 5 psi steam at 175 lbs/hr, and an output capacity of 300 gph at 120 feet of head. The water heater has a storage capacity of 127 gallons and temperature set point of 120 F. Service hot water is used for lavatory sinks, café sinks, and staff lounge sinks. There are no shower facilities at the Knight Law Center. Lighting Systems and Controls: The standard light fixture in the Law Center consists of two T8 lamps tied to a single electronic ballast. Decorative wall sconce lighting is present throughout the building; each of the approximately 78 sconce fixtures consists of two 13 W mini-fluorescent lamps powered by a single ballast. Lighting in most zones is either fully on or off; few areas are controlled by occupancy or photo sensors. Some classrooms have occupancy sensors and dimmers and there are a few photo sensors present in the library for daylighting control. The majority of lighting zones are controlled by wall switches, only some of which are linked to the central lighting controls. Most lighting for the Knight Law Center operates on 277V circuits. The lighting system is controlled by PCI panels throughout the building and is programmed with an after-hours sweep. Stairwell lighting and decorative sconce lighting stay on 24 hours a day. 5 ASHRAE Level One Energy Audit

6 On the first floor all of the corridor and atrium area lights are on one circuit, with no occupancy sensors or photo sensors. The first floor corridor and atrium lights are always on during normal operating hours. Electrical Distribution System: The building s electricity is on a 3-phase 480V system with three transformers located in the basement. Electricity is distributed to the building at 12.5 kv and stepped down to a 277/480V 3-phase service. HVAC and lighting circuits are connected to 277/480V busses while two other transformers step the voltage down to 120/208V for receptacles and smaller equipment. The building has a natural gas fired backup generator in case of electrical service outages. Building Envelop System: The Knight Law Center has steel frame construction with a brick façade. Glazing is double pane aluminum throughout. ENERGY USAGE ANALYSIS Energy end use breakdowns have been generated from an energy simulation with the webbased application Energy Profile Tool. Site data and observations along with standard assumptions were used to generate energy end use breakdowns for each energy type used in the building. The charts below breakdown the electricity consumption into the component end uses: heating, cooling, fans and pumps, lighting, and miscellaneous (includes elevators and receptacle loads). 6 ASHRAE Level One Energy Audit

7 Figure 1: Apportioned energy end uses for the Knight Law Center The energy breakdown of the Knight Law Center in fig. 1 above shows significant portions of the building s energy use in heating, lighting and fans and pumps. Lighting upgrades and HVAC upgrades which reduce fan use will yield the most savings. LEED SOURCE EUI BENCHMARK IMPLICATIONS The current source EUI for the Knight Law Center from Portfolio Manager through March 2011 is 158 kbtu/sf-yr. Note, as only 10 months of actual steam and chilled water usage data was available the last two months of the annual usage data for these two energy sources was estimated. As more than 10% of the space types in the Knight Law Center is classified as other in the EPA s Portfolio Managers energy performance rating tool, the Center is not eligible for an ENERGY STAR rating. An alternative method for comparing this building type s energy performance with like buildings is through the use of LEED s EA credit 1 case 2 calculator, an Excel spreadsheet which calculates an area weighted average source EUI from 7 ASHRAE Level One Energy Audit

8 CBECS data. Based on the results of this tool the Knight Law Center s equivalent ENERGY STAR rating is 62 or 12 percentile points above the national average of 50 (or 186 kbtu/sf-yr). To reach an ENERGY STAR target rating of 69, or 19 percentile points above the average, the Knight Law Center would need to reduce its source EUI to 144 kbtu/sf-yr, which is a 9% reduction over current energy usage. To achieve a target rating of 80 requires a source EUI of 113 kbtu/sf-yr or a 28% reduction over the current source EUI. IRREGULARITIES IN ENERGY USE Electricity use in kwh is consistent throughout the year. Monthly totals are slightly higher in the summer during peak cooling degree days, but also high for winter heating loads due to fan and pump energy. For the given usage history from January 2009 to April 2011, two months demonstrated a break from the typical trend over this period: both November 2009 and October 2010 were significantly lower in kwh than the months preceding and following. Meter history for district steam and chilled water indicate October 2010 was relatively mild for heating and cooling loads, which could explain the low electrical usage related to lower fan and pump energy usage. CURRENT OCCUPANCY RATES Between 580 and 590 students are enrolled at the law school with a faculty of about 82 and staff of 35. The building is fully occupied and space usage and occupancy rates have not varied significantly since the facility was originally occupied in ENERGY AUDIT PROCEDURE AND RESULTS One of the primary purposes of the ASHRAE Level I audit is to identify energy efficiency measures. For the EEMs suggested in this study, a simple cost benefit analysis has been performed to help determine the cost effectiveness of each measure. Paybacks of each EEM are based on estimates of installation costs and annual utility savings. A virtual rate based on the local utility EWEB rate structure of $0.065/kWh was used to estimate electricity cost savings. 8 ASHRAE Level One Energy Audit

9 Ted Spear, PE and Adam White, engineering intern, conducted a walk-through of the Knight Law Center on Friday, May 13 th The weather was mostly sunny with a high temperature of 68 F. Building systems and operations were discussed with facilities supervisors, and then the building was walked. HVAC and lighting systems were observed and photographed, and operations discussed with operating engineers, electricians and building management during the walk-through. Observations note during this site visit include: The north side of the building is regularly reported by tenants to be too cold, and space heaters are used to maintain comfort. Rooms with on-off control lighting circuits have issues with occupants leaving lights on all night. Wall sconce lighting fixtures remain on constantly. Project underway to install a split A/C system in the main server room. Building BAS Sequence of Operation modified from original set up, no formal written SOO plan exist. Plans to install VFD s on chilled water pumps underway. Although the BAS is programmed for night flush out and morning warm-up, those features are rarely employed as the environmental conditions do not warrant activation. The existing Café exhaust duct runs adjacent to the main IT server room. This exhaust duct could be tied to the server room to exhaust waste heat and possibly eliminate the need for the split A/C unit. There are plans to install VFD s on the chilled water distribution system and replace the existing 3-way chilled water bypass valve with a 2-way valve. This building currently does not meet minimum energy performance requirements by the USGBC under LEED for Existing Buildings Operations and Maintenance. These requirements state that the building must achieve an ENERGY STAR rating of 69 or greater. As was indicated previously, this buildings current equivalent ENERGY STAR rating is 62 and will need to reduce source energy consumption by approximately 2.1 million kbtu annually. To achieve this level of reduction will require the implementation of a number of the energy efficiency measures described below. EEMs that appear to provide the greatest energy savings per unit of investment include lighting upgrades, retrocommissioning, class room VAV occupancy sensor 9 ASHRAE Level One Energy Audit

10 control, and installation of VFD drives and a split A/C system for the main server room to provide an afterhours cooling source. RECOMMENDED ENERGY EFFICENCY MEASURES (EEM) Table 2 below shows suggested EEMs for the Knight Law Center, with savings and payback estimates. Estimates are conservatively based on energy savings associated with each EEM. Savings are estimated in kwh, lbs steam and lbs chilled water. To express savings in dollar amounts, the following conversion factors and virtual rates were used: 1 lb district steam = kbtu 100 kbtu of steam = 1 therm of natural gas 1 ton hour district chilled water = 12 kbtu 1 kbtu of chilled water = kwh Electricity: $0.065 per kwh Natural gas: $1.20 per therm Installation costs for more simple measures such as EEM 4, adding task lighting, assume labor will be performed by facilities staff and not make a significant contribution to the project cost. More complex measures such as EEM 6, installing hot water resets at VAV supply boxes, would require more time from facilities staff or hiring contractors and therefore include labor in the implementation cost estimates. Energy and cost savings are calculated for each measure separately. If multiple measures are implemented, the individual contribution of each measure will most likely be lower than predicted. 10 ASHRAE Level One Energy Audit

11 Table 1: Energy Efficiency Measures (EEM) EM # EEM Description Non Energy Operational Savings $ Energy Savings kbtu Installed Cost $ Estimate of Simple Payback [yrs] 1 Window Opening Indicators $0 102,668 $9, Lighting sensors and ground $0 2 floor re wiring 148,133 $18, Wall Sconce Re Lamping $0 25,645 $6, Library Task lighting $0 145,384 $13, Lighting control strategy $0 58,703 $ Retrocommissioning $0 513,296 $20, Occupancy sensor HVAC reset $0 7 for classrooms 51,330 $1, AHU 2 controls upgrade $0 102,965 $10, Variable frequency drives for $0 9 HW and CHW loop pumps 267,856 $20, Mini split A/C for server room $0 667,389 $25, Totals 2,083,368 $122, ASHRAE Level One Energy Audit

12 EEM-1: Window Opening Indicators This measure proposes indicator lights to be placed in all zones with operable windows, signaling occupants when it s okay to open windows or not based on the operation of the HVAC system. Current Condition: No indicators are in place to let building occupants know when opening the building s operable windows is allowed so as to avoid energy inefficiencies with the HVAC systems. When windows are opened during heating and cooling hours it can increase heating and cooling loads. This causes over-ventilation, which leads to excessive use of electricity, district steam and chilled water. Recommended Action: At each zone with operable windows, two indicator lights would be installed. A red light informs occupants that the windows are to remain shut and a green light that signals opening of window is allowed. Estimated Electricity Savings: 6,700 kwh Estimated Steam Savings: 21,200 lbs Estimated Chilled Water Savings: 450 ton-hours Estimated Cost: $9,625 Annual Savings: $3,100 Simple Payback: 3.1 years Assumptions: 30 zones have operable windows 1% annual savings in steam and chilled water 1% annual savings in fan and pump energy $25 per zone parts, 2 hours of labor per zone at $75 per hour 12 ASHRAE Level One Energy Audit

13 EEM-2: Lighting Sensors and Ground Floor Re-wiring This measure proposes to add occupancy sensors and daylight dimming photo sensors throughout the building, on as many lighting circuits as possible. This measure also proposes breaking up the corridor and atrium lighting on the first floor into multiple circuits. Current Condition: Few occupancy sensors and daylight dimming photo sensors are present in the Knight Law Center. Some of the classrooms have occupancy sensors, and the library has a daylight dimming sensor which is out of calibration. Without automatic controls, many zones in the building are lit when unoccupied. The first floor atrium provides great daylight resource, but the entire first floor corridor and atrium lighting is on one circuit, so it would not be practical to connect a daylight dimming photo sensor. Recommended Action: Installing occupancy sensors in all of the classrooms, restrooms, corridors, and student lounges will cut down on lighting kwh during occupied hours. Installing photo sensors will also cut down on lighting kwh for circuits near windows. Breaking up the first floor lighting will allow areas in the atrium to utilize daylight dimming and other areas to be controlled by occupancy sensors. Estimated Electricity Savings: 43,415 kwh Estimated Cost: $18,250 Annual Savings: $2,800 Simple Payback: 6.5 years Assumptions: Approximately 60 occupancy or photo sensors needed $50 per sensor, $75 per sensor for one hour of labor 5% savings in lighting kwh Occupancy and photo sensors are compatible with existing fixtures 13 ASHRAE Level One Energy Audit

14 EEM-3: Wall Sconce Re-Lamping This measure proposes to replace fluorescent lamps in each of the wall sconces with more efficient LEDs. Current Condition: Wall sconce luminaries throughout the building operate continuously, using 26W fluorescent lamps. Recommended Action: Replace the fluorescent lamps in wall sconce fixtures with LEDs. Facilities have expressed interest in using LEDs for wall sconces; the findings of this audit confirm this would be an energy saving measure. As long as wall sconce lights need to remain on continuously, upgrading the lamps will yield significant savings. Estimated Electricity Savings: 7,516 kwh Estimated Cost: $6,400 Annual Savings: $500 Simple Payback: 13 years Assumptions: Approximately 78 wall sconce fixtures $75 per LED lamp, minimal labor for installation LED lamps use 15W total per fixture LED lamp and ballast easily mount into existing fixture Savings based on the current 24/7 operation of wall sconce fixtures 14 ASHRAE Level One Energy Audit

15 EEM-4: Library Task Lighting This measure proposes to add task lights to decrease area lighting power density. This measure uses the library as an example, and could be applied to other lighting zones. Current Condition: Lighting power in the library is high to provide adequate illumination for reading and studying. Task lights are already present at some workstations, but more task lighting could be utilized to justify a reduction in ambient lighting power. Recommended Action: Add task lights to every table and desk in the library and use the PCI panel controls to dim the overhead lighting. Install timer switches on task lamps to come on for 30 minutes at a time, preventing occupants from leaving lights on after they leave a workstation. Estimated Electricity Savings: 42,600 kwh Estimated Cost: $13,750 Annual Savings: $2,800 Simple Payback: 5 years Assumptions: Approximately 37,000 sf of library space 1.2W/sf current lighting power density, 44.4 kw lighting power Library lit during normal operating hours, consumes 265,500 kwh annually $200 per task light, minimal labor for installation 30W per task lamp, 100 lamps needed Task lamp runtime is 3 hours per day average Area lighting can be dimmed to 0.9W/sf 15 ASHRAE Level One Energy Audit

16 EEM-5: Lighting Control Strategy This measure involves changing the lighting after-hours resets to lower power levels Current condition: Lighting circuits throughout the Knight Law Center are controlled by PCI panels, which are programmed for afterhours resets. Recommended Action: Lower after-hours reset power levels to provide additional savings. Estimated Electricity Savings: 17,200 kwh Estimated Cost: $0 Annual Savings: $1,100 Simple Payback: N/A Assumptions: Lighting control adjustments performed with in-house staff 2% annual savings in lighting energy 16 ASHRAE Level One Energy Audit

17 EEM-6: Retrocomissioning This measure recommends implementation of a retrocommissioning effort on all controlled energy consuming building systems. Current condition: The Knight Law Center has never been commissioned. Recommended Action: Retrocommission all building energy consuming systems. Estimated Energy Savings: 513,296 kbtu/yr Estimated Cost: $20,000 Annual Savings: $8,900 Simple Payback: 2.2 Assumptions: 5% Energy savings on heating, cooling, and ventilation systems. Costs based on industry average. 17 ASHRAE Level One Energy Audit

18 EEM-7: Occupancy sensor HVAC reset for classrooms This measure proposes to connect all classroom VAV distribution boxes to existing occupancy sensors so as to place the VAV box in an unoccupied mode when classrooms are vacant. Current Condition: Classrooms are held at occupied temperature during the building s operation hours. Classrooms are sporadically occupied, so there are blocks of time throughout the day where they could be allowed to switch into after-hours reset temperatures. Recommended Action: Connect occupancy sensors to VAV supply boxes in classrooms and program classroom zones to switch into after-hours reset temperatures when un-occupied. Estimated Energy Savings: 51,330 kbtu/yr Estimated Cost: $1,500 Annual Savings: $900 Simple Payback: 1.7 years Assumptions: Cost of each occupancy sensor approximately $50 2 hours install time per sensor, $75 per hour for labor 8 classrooms 1% fan power, steam and CHW reduction 18 ASHRAE Level One Energy Audit

19 EEM-8: AHU-2 Controls Upgrade This measure proposes updating temperature controls on AHU-2 and in the zones it serves. Current Condition: The north end of the Knight Law Center is reported by occupants to be over-cooled, mostly in the zones supplied by AHU-2. The over-cooling is prompting occupants to use portable space heaters to maintain comfort. Recommended Action: Check cold-deck reset sensors on AHU-2, and replace if necessary. Also, replace thermostats in all zones served by AHU-2. Estimated Energy Savings: 103,000 kbtu/yr Estimated Cost: $10,400 Annual Savings: $1,800 Simple Payback: 5.8 years Assumptions: Cost of each thermostat approximately $75 1 hour install time per sensor, $75 per hour for labor Approximately 20 zones in need of new thermostats % fan power reduction % steam use reduction % chilled water use reduction 19 ASHRAE Level One Energy Audit

20 EEM-9: HHW & CHW Circulating Pump VFD This measure proposes to install variable frequency drives on the CHW and HHW circulating pumps. Current Condition: The chilled and heating hot water circulating pumps operate at a constant speed regardless of the load condition. Flow through the system is controlled via three way bypass valves. The HHW pumps operate during occupied at hours while the CHW pumps remain on constantly to service the IT server room. This results in high cycling losses during part-load conditions, which is most of the year in Eugene. Recommended Action: Install VFD s on each of the circulating pumps and replace the existing 3-way by-pass valve with a 2-way valve. Demand-based variable frequency drives or other throttle controls for the hot and cold water circulation loop pumps will boost the part load efficiency of heating and cooling, reducing overall kwh use as well as kw demand. Estimated Energy Savings: 267,900 kbtu/yr Estimated Cost: $20,600 Annual Savings: $6,700 Simple Payback: 3.1 years Assumptions: Cost estimated at $5,000 per VFD 80% average load on and efficiency of pumps 20 ASHRAE Level One Energy Audit

21 EEM-10: Mini-Split System A/C for Server Room This measure proposes to install a split system A/C unit to serve the main IT server room during unoccupied hours. Current Condition: The main IT server room located on the second floor is conditioned by an existing AHU. The CHW pumps operate continuously to satisfy this constant cooling load. Recommended Action: Install a split system A/C fan coil unit to condition this room during the building s unoccupied hours. A mini-split heat air conditioner such as a Mitsubishi Mr. Slim would be an energy efficient option. Estimated Energy Savings: 667,400 kbtu/yr Estimated Cost: $25,600 Annual Savings: $6,700 Simple Payback: 2.3 years Assumptions: Approximately 2,700 after hours of operation per year Disclaimers The cost effectiveness of each energy efficiency measure has been estimated based on experiences with similar measures to provide an approximation of the value of the measure. Further analysis is recommended to identify the cost of each measure and resulting energy savings. 21 ASHRAE Level One Energy Audit

22 APPENDICES A. Statement of Energy Performance 22 ASHRAE Level One Energy Audit

23 23 ASHRAE Level One Energy Audit APPENDIX A: STATEMENT OF ENERGY PERFORMANCE

24 OMB No STATEMENT OF ENERGY PERFORMANCE Knight Law Center Building ID: For 12-month Period Ending: March 31, Date SEP becomes ineligible: N/A Date SEP Generated: May 24, 2011 Facility Knight Law Center 1515 Agate St Eugene, OR Year Built: 1999 Gross Floor Area (ft 2 ): 147,453 Facility Owner N/A Primary Contact for this Facility N/A Energy Performance Rating 2 (1-100) N/A Site Energy Use Summary 3 District Chilled Water - Electric-Driven Chiller(kBtu) 5,499,973 District Steam (kbtu) 2,547,212 Electricity - Grid Purchase(kBtu) 4,333,298 Natural Gas (kbtu) 4 4,400 Total Energy (kbtu) 12,384,883 Energy Intensity 5 Site (kbtu/ft 2 /yr) 84 Source (kbtu/ft 2 /yr) 158 Emissions (based on site energy use) Greenhouse Gas Emissions (MtCO 2 e/year) 849 Electric Distribution Utility Eugene Water & Electric Board Stamp of Certifying Professional Based on the conditions observed at the time of my visit to this building, I certify that the information contained within this statement is accurate. National Average Comparison National Average Site EUI 66 National Average Source EUI 143 % Difference from National Average Source EUI 11% Building Type Other Meets Industry Standards 6 for Indoor Environmental Conditions: Ventilation for Acceptable Indoor Air Quality N/A Acceptable Thermal Environmental Conditions N/A Adequate Illumination N/A Certifying Professional N/A Notes: 1. Application for the ENERGY STAR must be submitted to EPA within 4 months of the Period Ending date. Award of the ENERGY STAR is not final until approval is received from EPA. 2. The EPA Energy Performance Rating is based on total source energy. A rating of 75 is the minimum to be eligible for the ENERGY STAR. 3. Values represent energy consumption, annualized to a 12-month period. 4. Values represent energy intensity, annualized to a 12-month period. 5. Based on Meeting ASHRAE Standard 62 for ventilation for acceptable indoor air quality, ASHRAE Standard 55 for thermal comfort, and IESNA Lighting Handbook for lighting quality. The government estimates the average time needed to fill out this form is 6 hours (includes the time for entering energy data, Licensed Professional facility inspection, and notarizing the SEP) and welcomes suggestions for reducing this level of effort. Send comments (referencing OMB control number) to the Director, Collection Strategies Division, U.S., EPA (2822T), 1200 Pennsylvania Ave., NW, Washington, D.C EPA Form