PREDICTING AND MEASURING BUILDING ENERGY USE COURSE SUMMARY AND FINDINGS FINAL PRESENTATION Stan Lam Richard Tsai CEE 243 Professor Kunz May 31, 2011MAIN CHILLED WATER LOOPS  System or Component Description:  Main chilled water loop is connected to the central plant.  Chilled water is supplied into the building at about 45⁰F and exits the building between 55⁰F and 60⁰F after gaining heat through the cooling of the building’s equipment and air.  ID Numbers:  Utility Return Water Temperature Sensor – ID#1103  Utility Supply Water Temperature Sensor – ID#1104  Water Flow – ID#1143  Mixed Water Temperature Sensor – ID#1144  Point Source: Four sensors are used for monitoring and measurement of the main chilled water loop. 2MAIN CHILLED WATER LOOP SYSTEM DIAGRAM 32011 CHILLED WATER CONSUMPTION (TONS), CHILLED WATER FLOW RATE(GPM), AND OUTSIDE AIR TEMPERATURE (°F) • Function: As the chilled water flow rate increases or decreases, chilled water consumption also increases or decreases. This also correlates with the outside air temperature. • Performance: Green since performs as expected. Correlation between chilled water consumption, chilled water flow rate and outside air temperature. • Modes: There appears to be an occupied mode between 04:00 to 22:00. • There is a trend that follows the outside air temperature. 42009 AND 2011 MAIN CHILLED WATER RETURN AND SUPPLY TEMPERATURES  Yellow Light: Although the temperatures appear to be operating within the expected range, there are missing data.  #1, #2, #3, #4 shows the trendlines for the chilled water supply and return temperatures.  The ReturnTemp did not change from 2009 to 2011.  However, the SupplyTemp appears to have changed from 45°F in 2009 to 43.5°F in 2010. Since the chilled water supply comes from the main chiller plant, inquiring with the Building/Facilities Management would be necessary for reason.  #5 shows a spike in the SupplyTemp. The spike is also reflected in the ReturnTemp as expected. The spikes in are probably due to an increased demand from other buildings or some other activity made at the chiller plant.  #6 Missing Data: Periods where there is missing data.  Recommendation: For missing data, a program could be created to evaluate all the data point for the missing data and generate a report. 2 3 4 1 2009 2011 6 6 5 5TEMPERED CHILLED WATER LOOPS  System or Component Description:  Tempered chilled water loop feeds water directly into the active beams of Y2E2.  Water temperature in these systems is around 50⁰F.  ID Numbers:  Return Water Temperature Sensor – ID#2400002  Supply Water Temperature Sensor – ID#2400001  Supply Temperature Setpoint – ID#1195  Differential Pressure Sensor – ID#8740009  Differential Pressure Setpoint – ID#1203  Point Source: Sensors are used for monitoring and measurement of the tempered chilled water loop 6TEMPERED CHILLED WATER LOOP SYSTEM DIAGRAM 72011 TEMPERED CHILLED WATER  Supply Setpoint:55°F  Function: Maintain temperate chilled supply water temperature setpoint by opening and closing control valve  Green Band: Within 5% of setpoint  Performance: Green since performs as expected. Valve opens and closes to maintain setpoint temp.  Mode: Occupied.  At #1, as SupplyTemp increase above setpoint (55°F), valve opening increases until #2.  At #3, valve closing as SupplyTemp decreases and SupplyTemp is above setpoint. Temperate Chilled Water Supply Temp Temperate Chilled Water ValvePos 1 2 3 4 82009 AND 2011 TEMPERED CHILLED WATER RETURN AND SUPPLY TEMPERATURES CARPET PLOTS  Yellow Light: Further investigation needed to determine if a problem actually exists.  #1 shows the occupied mode of 2009 ReturnTemp from 06:00 to 19:00.  #2 shows occupied mode for 2011 ReturnTemp from 04:00 to 22:00.  Occupied hours increased from 2009 to 2011. Was this intentional? Possible savings if revert back to 2009 occupied hours.  #3 Missing data: Large portion of January 2009 and other periods where the color of carpet plot is white in 2009 and 2011.  #4 We see occupied hours shift due to daylight savings.  #5 We also see a shift back to schedule prior to daylight savings near beginning of April. Possibly due to a seasonal shift in schedules?  Recommendation: Investigate the reason for increasing the occupied schedule and possibly revert back to a more reduced occupied schedule for energy savings. For missing data, a program could be created to evaluate all the data points for the missing data and generate a report. 3 3 3 3 2009 2011 1 2 4 4 5 5 3 92009 HEAT RECOVERY BYPASS VALVE PROBLEM  Heat recovery bypass valve opens and closes rapidly during transitional periods  Recommendation: Program Heat Recovery Bypass Damper to include a time delay of at least 2 minutes 10FUNCTION OF HEAT RECOVERY BYPASS VALVE  From Week 3 Lecture, Y2E2 – HVAC sequence of operation (controls)  Heating  If  outside air temperature < heat recovery leaving temperature &  exhaust air temperature > heat recovery leaving temperature  Then -> heat recovery bypass damper closed (heat recovery “on”) otherwise open  Heat recovery bypass damper modulates to set supply air temperature to setpoint (65°F)  Cooling  If outside air temperature > exhaust air temperature  Then -> heat recovery bypass damper closed (heat recovery “on”) otherwise open  Heat recovery bypass damper modulates to set supply air temperature to setpoint (65°F) 112009 HEAT RECOVERY BYPASS VALVE PROBLEM  Red light because of the problem of the valve rapidly opening and closing.  According to the function for the heat recovery bypass valve from previous slide, valve does not function correctly.  For heating: Valve=0% when, Exhaust Temp > Heat recovery leaving temp > Outside Temp 122009 HEAT RECOVERY BYPASS VALVE PROBLEM  Red light because of rapid cycling of valve.  Problem of heat recovery bypass valve rapidly opening and closing at transition.  Band of heat recovery mode should be wider according to the function of the heat recovery bypass valve.  For heating: Valve=0% when Exhaust Temp > Heat recovery leaving temp > Outside Temp 132011 HEAT RECOVERY BYPASS VALVE PROBLEM  Yellow light. Original problem corrected, but new problems.  Although the valve no longer have the problem of rapidly opening and