Level II - Whole Building Interval Electric Data with Tenant Plug Load System

Transcription

1 Level II - Whole Building Interval Electric Data with Tenant Plug Load System 1. Overview and Scope This specification describes the capabilities and data requirements for equipment or service providers that provide energy analysis data for this commercial building. It specifies collection of building characteristics, monitoring data, required analysis, and reporting intervals that must be delivered Scope In general this specification defines the composition of whole building and system meter data and specifies the use of tools and algorithms for creating certain plots and graphs, requirements for comparisons, and reporting intervals. Hardware including data acquisition and metering equipment is not covered by this specification except for its capabilities to meet the requirements for data, analysis, and reporting via a userfriendly web-based software tool. Electric and fuel usage shall be net of the contribution of On-site Generation so that the building s consumption is accounted for accurately. 2. Data Requirements: 2.1. Fuels Natural Gas Usage data shall be collected at monthly or near monthly intervals on all fuels for 24 months beginning 3 months after project completion or when specified by the owner. It is assumed that this will be utility bill data. If 15-minute usage intervals are available then the usage shall be rolled up into monthly usage periods Electricity Usage data shall be collected at 15-minute usage intervals for electric usage of the entire building for 24 months beginning 3 months after project completion or when specified by the owner Tenant Plug Load Electric System Usage A subset of electric usage data shall be collected at 15-minute usage intervals for the aggregated electricity use of the plug loads of the buildings occupants or tenants, excluding common areas, core and shell, people moving equipment, integrated retail, large data centers, and other plug and non-plug load that is not directly used by the occupants or tenants Other Fuels When easily collectible, usage data shall be collected at monthly or near monthly intervals for other fuel usage of the entire building for 24 months beginning 3 months after project completion or when specified by the owner Weather Data

2 Energy analysis using average local weather data shall use the closest suitable nearby standard NOAA weather station Building Characteristics The following building characteristics shall be collected one time and used to describe the commercial building. The building characteristics include any building characteristics required by the Energy Star Portfolio Manager system described in Table 1 in addition to the building characteristics in Table 2. Table 1 Required Building Characteristics Energy Star Portfolio Manager 1 Building Characteristic Description Use-Type CBECS Building Use Type 2 Zip Code Address Zip Code GSF Building Gross Square Footage Conditioned % of GSF Percent of GSF that is heated and cooled Weekly Operating Hours Number of Hours per week that the building is occupied Number of Workers on the Main Shift Number of workers estimated on the day shift Number of Personal Computers Number of personal computers in the whole building Detailed Section Table 2 Additional Building Characteristics and Descriptions Building Characteristic Description Section Window to Wall Ratio (WWR) Estimated window-to-wall ratio for the overall Building Sky Glass Percent of roof area that is skylights Average Ceiling Height Estimated average height from floor to ceiling in the total building Foundation/Lower Floor Type Type of construction used for grade/below grade Number of Buildings If the whole building is a site of multiple buildings Number of Floors Average number of floors in the building Average Wall Insulation (Rvalue) Estimated Average wall R-value excluding windows Average Roof Insulation (Rvalue) Estimated Average roof R-value excluding skylights Heating Fuel Fuel used for primary heating system Primary Heating Type Selected from a menu that summarizes the heating method. Primary Heating Capacity Total nameplate capacity per SF (kbtu/sf) of the primary heating equipment. Primary Cooling Type Selected from a menu that summarizes the cooling method. Primary Cooling Capacity Total nameplate capacity per SF (kbtu/sf) of the primary cooling equipment. 1 The characteristics change slightly based on use type. These are the characteristics for office buildings. 2 Refer to

3 Reheat Type Type of reheat method used by the HVAC system HVAC Typology Defines how heating and cooling are distributed Ventilation Type Defines how fresh air is brought into the building Lighting Installed Capacity (W/SF) Estimated installed lighting capacity in W/SF in total building Indoor Direct Loads Large electrical loads inside the envelope of the building Outdoor Direct Loads Large electrical loads outside the envelope of the building Data Center Is there a data center in the building that is larger than 3% of floor area and has dedicated cooling? Service Hot Water Fuel Fuel used to make service hot water Energy Star Portfolio Manager Building Characteristics EPA s Energy Star Portfolio Manager (EPA PM) tool requires certain building characteristics to be recorded for each building that receives a score. Note that this set of characteristics is dependent of building use-type. This specification requires the collection of the building characteristics required by EPA PM for the appropriate building use-type Window-to-Wall Ratio (WWR) The exact or best estimate of the window-to-wall ratio for the overall building as a percentage Sky Glass The exact or best estimate of the roof area that is skylights for the overall building as a percentage Average Ceiling Height An estimate of the average height from floor to ceiling for all floors of the whole building Foundation Lower Floor Type The type of foundation or lower floor type for the building. Restricted to one of the following: Slab on grade Parking garage Basement Number of Buildings If the whole building is actually a complex of buildings (such as with a school) then this field is the number of buildings in the complex. For other building characteristics such as Number of Floors the estimated average for all the buildings shall be used Number of Floors The number of floors in the building above grade Average Wall Insulation An estimate of the average R-value for all walls excluding windows Average Ceiling Insulation An estimate of the average R-value for the roof excluding skylights Heating Fuel

4 The primary heating fuel for the heating system. Restricted to: Electricity Natural Gas Other fuel District Steam or Hot water Steam None Primary Heating Type and Primary Heating Capacity The primary equipment for heating the building. Restricted to: Boiler Gas Pack Heat Pump Ground Source Heat Pump VRF None Also the total nameplate rating of all primary heating equipment divided by the GSF of the building expressed in kbtu/sf. Electric reheat is excluded Primary Cooling Type and Nameplate Cooling Capacity Select the label that best describes the primary cooling equipment for the building. DX Vapor compression based equipment Heat Pump Chiller air cooled Chiller water cooled Ground Source Heat Pump VRF District Chilled Water None Also the nameplate rating of all primary cooling equipment divided by the GSF of the whole building expressed in kbtu/sf. Small distributed equipment is excluded Reheat Type Type of reheat used by the HVAC system. Restricted to: Electric Hydronic None HVAC Typology A label that best describes the general HVAC approach used by the building: Restricted to: Chiller/Boiler built-up/ VAV or other Chiller/Boiler Radiant RTU One-per-Zone RTU built-up/vav VRF

5 Ground Source Heat Pump Heat Pump Distributed window/wall AC and zone heaters None Ventilation Type Select the label that best describes the means by which the majority of fresh air is delivered to the building. Restricted to: With heating and/or cooling Direct Outdoor Air (DOAS) (separate from heating and cooling) Natural Ventilation Lighting Installed Capacity (W/SF) The exact or an estimated amount of total installed capacity of lighting in the building in W/SF Indoor Direct Loads A Yes or No question regarding the presence of significant equipment inside the envelope that consumes energy not related to the thermal management of the building, people moving, or occupant activities and is estimated to be greater than 5% of building annual usage Outdoor Direct Loads A Yes or No question regarding the presence of significant equipment outside the building envelope that is not related to the thermal management of the building, people moving, or occupant activities and is estimated to be greater than 5% of building annual usage Data Center A Yes or No question regarding the presence of a data center. See the definitions section for clarification on what constitutes a data center Service Hot Water (SHW) Fuel The type of fuel that serves hot water needs for the building. Restricted to: Electric Natural Gas District hot water None 3. KPI Analysis Requirements Standardized analysis using comparisons translates meter data into useful assessments of how the building uses energy. The required analysis is described in the section while the reporting intervals are described in Section 4. The requirements for the analysis described in this section do not preclude any additional analysis or reporting that may be beneficial to the owner EPA Portfolio Manager Score The portfolio manager score shall be calculated for the building based on the collected bill data. Specific instructions for calculations are available on the Energy Star Website.

6 3.2. EnergyIQ Tool (For buildings in California) Rank For buildings located in California the energy IQ Tool shall be used to calculate the energy performance score compared to California buildings. Additional building characteristics shall be collected as necessary to meet the requirements of the tool FirstView Tool Indicators The FirstView web tool shall be used to calculate the KPIs listed below: Occupant Load Shell and Ventilation Effectiveness Cooling Efficiency Control Problems Summer Gas Use Reheat 3.4. Simple Energy Signature and Comparisons Whole Building Several types of plots based on monthly usage periods shall be created along with the ability to overlay the comparison plots specified in this section. The energy signature is an X-Y representation with 12 plotted points per series. Each monthly usage period for each fuel forms a point by converting energy usage into an average energy use rate per square foot in Watts per GSF (forming the Y-axis value) plotting against the average daily dry-bulb air temperature in the same usage period (forming the X-axis value) using daily temperature data collected per 2.2. Each fuel individually, and the total of all fuels, are plotted using markings and coloration to clearly identify each series. The series shall be capable of being compared visually to certain comparisons by overlaying plots described in through as applicable Design Model Comparison (if applicable) If a design model was used to project the energy output of the building the energy signature of that model shall be included as a comparison plot. This plot shall use the monthly energy usage output for all fuels as the Y-axis value and the average dry-bulb temperature input (taken from the weather file used for the model run) as the X-axis. The plots shall be created as described in Year-over-Year Comparison A comparison energy signature that uses the preceding 12-months to the current trailing 12- months; or the preceding calendar year to the current calendar year.

7 Comparison Cloud (when available) When available a comparison of the trailing 12-month energy signature to a group of signatures that represent the lowest and highest energy users of similar buildings Whole Building Weekday Schedule Assessment (WBSA) The Whole Building Weekday Schedule Assessment uses a simple algorithm to parse the whole building electric interval data to summarize the approximate usage schedule in hours per day of the whole building. The algorithm examines each day individually then compiles the data for the usage or analysis period The 15-minute electric interval data for a desired period is collected so that the data begins and ends at 12:00 AM on the first and last day of the period The average value at each 15-minute interval across all the weekdays (i.e. excluding weekends and federal holidays) in the period is calculated resulting in a typical weekday profile of 96 points from 12:00AM to 11:45PM The set of minute data points of an average weekday are divided into three exclusive sets, independent of time of day. The sets designate if the demand at a point is greater than (H), within (T), or less than (L) a band one standard deviation in width, centered around the mean of the full set. The criteria for each set are shown in equations below: High-load data set: [ ( )] Transition data set: [ ( ) ( )] Low-load data set: [ ( )] The WBSA is the duration in hours for a typical day using the following equation: WBSA = 3.6. System Meter Indicators - Tenant Plug Load System These calculations use the subset of interval data from the tenant plug load system data specified in They shall be calculated using the appropriate usage and analysis periods and at the frequency specified in Table 4. Note the definitions in the table that make subtle distinctions in the analysis periods and display of results Tenant Schedule Assessment This calculation is similar to the Whole Building Schedule Assessment but provides a more accurate representation of the schedule of the occupants themselves, rather than the whole building and its systems. The tenant schedule assessment shall be calculated using the procedure in Section 3.5 but using the data from the tenant plug load system only Tenant Schedule Stability The tenant stability indicator is comprised of a plot of two metrics that combine to demonstrate if tenant plug load is showing high variability, implying a large change in

8 occupancy. The indicator uses 12 usage periods for annual frequency or 3 usage periods for quarterly frequency and displays the metrics in a chart or table. The first metric is the Occupied Power Density and the second is the Tenant Schedule Assessment described in Occupied Power Density. This is the average power per GSF on non-holiday weekdays between 6:00AM and 6:00PM. To calculate, the average power of the tenant plug load system from 6:00AM to 6:00PM hours is found for each day in that qualifies as a weekday (i.e. excluding Saturdays, Sundays, and holidays) and the average is taken across all weekdays in the usage period. The result is divided by GSF and expressed in W/SF Tenant Schedule Assessment. The metric described in calculated for the usage period Tenant Usage The Tenant Usage indicator is comprised of five metrics of calculation that summarize aspects of the tenant usage for an annual or quarterly reporting frequency. An annual reporting frequency averages across all the tenant plug load system data for a full year analysis period while the quarterly frequency uses the trailing 3 usage periods as an analysis period. The metrics are displayed in a table The Occupied Power Density. Described in The Peak Power Density. The peak power density is the maximum power selected from all 15-minute power measurements in the analysis period divided by the GSF and expressed in W/SF The Weekday Power Density. The weekday power density is calculated by finding the average power for over 24-hours for each day that qualifies as a weekday (i.e. excluding Saturdays, Sundays, and holidays). The average is taken for all weekdays in the analysis period and divided by GSF and expressed in W/SF The Off Hours Ratio. The off hours ratio calculates a fraction by dividing the nighttime power density by the occupied power density. The nighttime power density is found using the process described in except that the average power density from the time window of 6:00PM to 6:00AM is used. The fraction is expressed as a percent The Weekend Ratio. The weekend ratio calculates a fraction by dividing the weekend power density by the weekday power density. The weekend power density is calculated using the process described in but uses only non-weekdays (i.e. only Saturdays, Sundays, and Holidays). The fraction is expressed as a percent Tenant Plug Load Feedback The tenant plug load feedback indicator provides monthly tenant usage updates using several metrics that tenants can view updated on a monthly basis. The analysis period and reporting frequency for all metrics is monthly Occupied Power Density. Calculated as described in Peak Power Density. Calculated as described in Off-hours Ratio. Calculated as described in

9 Weekend Ratio. Calculated as described in Annualized Energy Density. The annualized energy density (AED) is a projection of the energy that the tenants will use in a year per GSF based on the limited analysis period. The calculation uses estimates of 251 weekdays and 114 weekends (including holidays) multiplied by the weekday power density (P WKD ) and the weekend power density (P WEND ) using the equation below. The result should be rounded to 2 significant digits. 4. Reporting Requirements This section provides minimum requirements for reporting of the data analysis in Section 3. Start and end dates for Annual, Quarterly, and Monthly indicators should align whenever possible. Table 3 Whole Building Designer KPI Reporting and Display Requirements Analysis KPI Portfolio Manager Score Energy IQ Rating First View Indicators Energy Signatures Whole Building Schedule Assessment Trailing 12-Month Calendar Year(s) Reporting Frequency Annually Annually Annually Monthly Annually Annually Quarterly Comments Using trailing 12 usage periods and update with each monthly usage period Using calendar year data and updated with each usage period. Using calendar year data when a full year is available. Reported quarterly using the trailing 3 month data Table 4 System Level Meter Indicators Reporting Frequency and Display Requirements by System Meter KPIs Audience Designer Operator Tenant Tenant Schedule Assessment Annually Quarterly Monthly Tenant Stability Annually Quarterly - Tenant Usage Annually Quarterly - Tenant Plug Load Feedback - - Monthly 5. Definitions 5.1. Whole Building The structure that is being analyzed by accounting for fuels consumed at the site accounting for on-site generation. The building size is defined by the gross square footage

10 (GSF). For some commercial use-types such as schools the whole building may consist of several structures on a single utility meter Analysis period The period of time of interval data (e.g. annual, 3 months, 2 months) used in the calculation of energy metrics used in the indicators Gross Square Footage The measurement of a building s area per EPA Portfolio Manager Data Center A large area of a building s GSF (greater than 3%) that is dedicated for the purpose of housing servers, switches, and IT equipment for a large portion of the whole building. In this definition a data center will have dedicated cooling equipment. A smaller installation on a single floor that serves a specific tenant and may or may not have dedicated cooling constitutes a server closet and shall not be considered a data center. The vendor shall use their best judgment to determine the presence of a data center Fuel Any energy source used by the building including electricity, natural gas, propane, butane, oil, heated or chilled water, or steam Usage Period A period of time, more or less a month in length, that is used as a data point for energy signature analysis. Usage periods can be defined by utility bill read dates or by a convention for rolling up interval meter data to near monthly intervals Utility Bill Any accounting of energy provided by an energy provider, usually an incorporated electric or gas utility, which accounts for energy used in a usage period Interval Meter A fuel meter that takes measurements frequently, at least hourly, and collects data in a database for analysis Usage Interval The time frequency for each measurement from an interval meter (e.g. 15- minute interval is every 15 minutes. As an example, utility bills have a usage interval of monthly) On-site Generation Any generation of electricity that is used in the whole building and displaces energy that would have been purchased from a utility. E.g. CHP electricity output or PV output Reporting Frequency The frequency at which an indicator, using a certain analysis period and accompanying usage periods, should be calculated.