ASHRAE HVAC APPLICATIONS SI CH 41-2015 BUILDING ENERGY MONITORING.pdf

1、41.1CHAPTER 41BUILDING ENERGY MONITORINGReasons for Energy Monitoring 41.1Small Projects . 41.3Protocols for Performance Monitoring 41.3Common Monitoring Issues 41.6Steps for Project Design and Implementation 41.6UILDING energy monitoring was conducted on a large scale inB the 1980s and 1990s, and t

2、he need to capture lessons learnedand document project requirements that often were not addressedadequately in these large projects led to the development of thischapter. The intent of such projects is to provide realistic, empiricalinformation from field data to enhance understanding of actualbuild

3、ing energy performance and help quantify changes in perfor-mance over time. Although different building energy monitoringprojects can have different objectives and scopes, all have severalissues in common that allow methodologies and procedures (moni-toring protocols) to be standardized.This chapter

4、 provides guidelines for developing building moni-toring projects that provide the necessary measured data at accept-able cost. The intended audience comprises building owners,building energy monitoring practitioners, and data end users such asenergy and energy service suppliers, energy end users, b

5、uilding sys-tem designers, public and private research organizations, utilityprogram managers and evaluators, equipment manufacturers, andofficials who regulate residential and commercial building energysystems. A new section has been added on small projects to showhow the methodology can be simplif

6、ied.Monitoring projects can be uninstrumented (i.e., no additionalinstrumentation beyond the utility meter) or instrumented (i.e., bill-ing data supplemented by additional sources, such as an installedinstrumentation package, portable data loggers, or building automa-tion system). Uninstrumented app

7、roaches are generally simpler andless costly, but they can be subject to more uncertainty in interpreta-tion, especially when changes made to the building represent a smallfraction of total energy use. It is important to determine (1) the accu-racy needed to meet objectives, (2) the type of monitori

8、ng needed toprovide this accuracy, and (3) whether the desired accuracy justifiesthe cost of an instrumented approach.Instrumented field monitoring projects generally involve a dataacquisition system (DAS), which typically comprise various sensorsand data-recording devices (e.g., data loggers) or a

9、suitably equippedbuilding automation system. Projects may involve a single buildingor hundreds of buildings and may be carried out over periods rangingfrom weeks to years. Most monitoring projects involve the followingactivities: Project planningSite installation and calibration of data acquisition

10、equipment (if required)Ongoing data collection and verification Data analysis and reportingThese activities often require support by several professional dis-ciplines (e.g., engineering, data analysis, management) and con-struction trades (e.g., electricians, controls technicians, pipe fitters).Usef

11、ul building energy performance data cover whole buildings,lighting, HVAC equipment, water heating, meter readings, utilitydemand and load factors, excess capacity, controller actuation, andbuilding and component lifetimes. Current monitoring practices varyconsiderably. For example, a utility load re

12、search project may tend tocharacterize the average performance of buildings with relatively fewdata points per building, whereas a test of new technology perfor-mance may involve monitoring hundreds of parameters in a single fa-cility. Monitoring projects range from broad research studies to veryspe

13、cific, contractually required savings verification carried out byperformance contractors. However, all practitioners should use ac-cepted standards of monitoring practices to communicate results.Key elements in this process are (1) classifying the types of projectmonitoring and (2) developing consen

14、sus on the purposes, ap-proaches, and problems associated with each type (Haberl et al. 1990;Misuriello 1987). For example, energy savings from energy serviceperformance contracts can be specified on either a whole-building orcomponent basis. Monitoring requirements for each approach varywidely and

15、must be carefully matched to the specific project. Proce-dures in ASHRAE Guideline 14-2002 and the IPMVP (2007) can beused to determine monitoring requirements.1. REASONS FOR ENERGY MONITORINGMonitoring projects can be broadly categorized by their goals,objectives, experimental approach, level of mo

16、nitoring detail, anduses (Table 1). Other factors, such as resources available, data vali-dation and analysis procedures, duration and frequency of data col-lection, and instrumentation, are common to most, if not all,projects.Energy End UseEnergy end-use projects typically focus on individual energ

17、y sys-tems in a particular market sector or building type. Monitoring usu-ally requires separate meters or data collection channels for each enduse, and analysts must account for all factors that may affect energyuse. Examples of this approach include detailed utility load researchefforts, evaluatio

18、n of utility incentive programs, and end-use calibra-tion of computer simulations. Depending on the project objectives,the frequency of data collection may range from one-time measure-ments of full-load operation to continuous time-series measure-ments.Specific Technology AssessmentSpecific technolo

19、gy assessment projects monitor field perfor-mance of particular equipment or technologies that affect buildingenergy use, such as envelope retrofit measures, major end-use sys-tem loads or savings from retrofits (e.g., lighting), or retrofits to orperformance of mechanical equipment.The typical goal

20、 of retrofit performance monitoring projects is toestimate savings resulting from the retrofit despite potentially signif-icant variation in indoor/outdoor conditions, building characteris-tics, and occupant behavior unrelated to the retrofit. The frequencyand complexity of data collection depend on

21、 project objectives andsite-specific conditions. Projects in this category assess variations inThe preparation of this chapter is assigned to TC 7.6, Building Energy Per-formance.41.2 2015 ASHRAE HandbookHVAC Applications (SI)performance between different buildings or for the same buildingbefore and

22、 after the retrofit.Field tests of end-use equipment are often characterized by de-tailed monitoring of all critical performance parameters and op-erational modes. In evaluating equipment performance or energyefficiency improvements, it is preferable to measure in situ perfor-mance. Although manufac

23、turers data and laboratory performancemeasurements can provide excellent data for sizing and selectingequipment, installed performance can vary significantly from thatat design conditions. The project scope may include reliability,maintenance, design, energy efficiency, sizing, and environmentaleffe

24、cts (Phelan et al. 1997a, 1997b).Savings Measurement and Verification (M (2) fan pressurization tests to measure and locate buildingenvelope air leakage (ASTM Standard E779) and tests to measureairtightness of air distribution systems (Modera 1989; Robison andLambert 1989); and (3) infrared thermogr

25、aphy to locate thermaldefects in the building envelope and other methods to determineoverall building envelope parameters (Subbarao 1988).Table 1 Characteristics of Major Monitoring Project TypesProject Type Goals and Objectives General Approach Level of Detail UsesEnergy end use Determine character

26、istics of specific energy end uses in building.Often uses large, statistically designed sample. Monitor energy demand or use profile of each end use of interest.Detailed data on end uses metered. Collect building and operating data that affect end use.Load forecasting by end use. Iden-tify and confi

27、rm energy conserva-tion or demand-side management opportunities. Simulation calcula-tions. Rate design.Specific technology assessmentMeasure field performance of building system technology or retrofit measure in individual buildings.Characterize individual build-ing or technology, occupant behavior,

28、 and operation. Account and correct for varia-tions.Uses detailed audit, sub-metering, indoor temperature, on-site weather, and occupant surveys. May use weekly, hourly, or short-term data.Technology evaluation. Retrofit performance. Validate models and predictions.Energy savings measurement and ver

29、ificationEstimate the impact of retrofit, commissioning, or other build-ing alteration to serve as basis for payments or benefits calcu-lation.Preretrofit consumption is used to create baseline model. Post-retrofit consumption is mea-sured; the difference between the two is savings.Varies substantia

30、lly, includ-ing verification of potential to provide savings, retrofit isola-tion, or whole-building or cal-ibrated simulation.Focused on specific campus, build-ing, component, or system. Amount and frequency of data var-ies widely between projects.Building operation and diagnosticsSolve problems. M

31、easure phys-ical or operating parameters that affect energy use or that are needed to model building or system performance.Typically uses one-time and/or short-term measurement with special methods, such as infra-red imaging, flue gas analysis, blower door, or coheating.Focused on specific building

32、component or system. Amount and frequency of data vary widely between projects.Energy audit. Identify and solve operation and maintenance, indoor air quality, or system problems. Provide input for models. Building commissioning.Building Energy Monitoring 41.3Energy systems in multifamily buildings c

33、an be much more com-plex than those in single-family homes, but the types of diagnosticsare similar: combustion equipment diagnostics, air leakage mea-surements, and infrared thermography to identify thermal defects ormoisture problems (DeCicco et al. 1995). Some techniques aredesigned to determine

34、the operating efficiency of steam and hot-water boilers and to measure air leakage between apartments.Diagnostic techniques have been designed to measure the overallairtightness of office building envelopes and the thermal performanceof walls (Armstrong et al. 2001; Persily et al. 1988; Sellers et a

35、l.2004). Practicing engineers also use a host of monitoring techniquesto aid in diagnostics and analysis of equipment energy performance.Portable data loggers are often used to collect time-synchronized dis-tributed data, allowing multiple data sets (e.g., chiller performanceand ambient conditions)

36、to be collected and quickly analyzed. Simi-lar short-term monitoring procedures are used to provide moredetailed and complete commercial building system commissioning.Short-term, in situ tests have also been developed for pumps, fans,and chillers (Phelan et al. 1997a, 1997b).Diagnostics are also wel

37、l suited to support development andimplementation of building energy management programs (seeChapter 36). Long-term diagnostic measurements have even sup-ported energy improvements (Liu et al. 1994). Diagnostic measure-ment projects can generally be designed using procedures adaptedto specific proje

38、ct requirements (see the section on Steps for ProjectDesign and Implementation).Equipment for diagnostic measurement may be installed tempo-rarily or permanently to aid energy management efforts. Designersshould consider providing permanent or portable check metering ofmajor electrical loads in new

39、building designs. Building automa-tion systems also can be used to collect the data required for diag-nostics. The same concept can be extended to fuel and thermalenergy use.2. SMALL PROJECTSMost energy metering projects are done on a small scale and willhave the project steps described in this chap

40、ter simplified and com-pacted. This section describes briefly how to use the information inthis chapter for a small project.Small projects will still be potentially impacted by the issuesdescribed here, but if only a small group of people are doing all thework, they can choose what to address and ho

41、w to address the proj-ect requirements. Table 2 compares small-project approaches andthe material in this chapter.How to Use This Chapter for Small ProjectsSkim through the chapter and make a few notes on items that mayapply for the project in question.Generate a brief project plan to make sure majo

42、r issues that maycause problems are not overlooked.Generate a brief checklist from the item notes for final check-offduring or at the end of project.Clarify what building or site characteristics data may be needed,and be sure to collect those data.Analyze data from the start, to make sure there are

43、no quality ordata issues.Consider whether any data should be made available to others atthe end of the project, and if so, develop a data format forexchange.Skim through the chapter again when the report is being preparedto gather ideas about what to include in the report.3. PROTOCOLS FOR PERFORMANC

44、E MONITORINGExamples of procedures (protocols) for evaluating energy savingsfor projects involving retrofit of existing building energy systems areTable 2 Comparison of Small Projects to Overall MethodologyProject Characteristic Small Project Approach Overall Methodology CoverageProject problem area

45、s Project goals and resources are iteratively evaluated in short time. Only one to possibly a few people involved. Small group allows more informal procedures and high interaction as needed.Project goals, project costs and resources, data products, data management, data quality control, commitment,

46、accuracy requirements, advice.Data products loosely defined. Data collection starts. Initial and ongoing analysis indicates any data management or quality control issues.Data products refined over time as needed, based on analysis.Accuracy evaluated on the fly as data are collected.Commitment is sim

47、ply needing to finish the work.Advice still sought where needed.Building and occupant characteristicsTypically, only one to few buildings included; work is reasonably local. Characteristic data collected on site, at convenience of project person(s), depending on project location. Return trips likely

48、 already needed for simplified data collection approach; supporting data can be collected on return trips.Fairly extensive data structure (e.g., a characteristic database) and definition of levels of detail may be needed to handle possibly many buildings and improve ability to report results. With m

49、any buildings, only one trip per building may be acceptable.Project design Project personnel usually know what they want to measure and report, and may not want to be confused by complex approach in this chapter. Knowledge of experimental approaches may also be understood minimally but still applied successfully, without specific declaration, to small project.Three higher-level general approaches: (1) fewer buildings or systems with more detailed measurements, (2) many buildings or systems with less detailed measurements, or (3) many buildings or systems with more detailed measurements.