ASHRAE AB-10-005-2010 Screening of Energy Efficient Technologies for Industrial Buildings’ Retrofits.pdf

1、2010 ASHRAE 401ABSTRACTDuring the past few years, U.S. Army Corps of Engineers Engineer Research and Development Center (ERDC) has led energy and process optimization initiatives to help Department of Defense installations to meet energy efficiency and environ-mental compliance requirements and to c

2、reate an improved work environment. This effort was also a part of the IEA- ECBCS “International Energy Agency Energy Conservation in Buildings and Community Systems” Annex 46, “Holistic Assessment Tool-kit on Energy Efficient Retrofit Measures for Government BuildingsEnERGo.”One of the important ta

3、sks of both programs was to analyze a series of international experiences of retrofitted industrial buildings and based on these best practice examples to develop a database of promising energy saving technologies and measures (current, proven, well known or underused). The database includes technol

4、ogies/measures that relate to build-ing envelope, internal load reduction, lighting, HVAC systems, energy consuming processes in the building, supplemental energy systems (e.g., compressed air, steam system), etc. The listed technologies and measures cover a wide spectrum, from proven operations and

5、 maintenance procedures to installation of technologies that have recently entered the market and are not yet well understood by end users, engineers, and decision makers. They also span a wide range of capital investment costs, from no cost/low cost measures to installations that may require severa

6、l hundred thousand dollars of investment. Appli-cability and savings from using some energy conservation technologies and measures are not affected by outdoor climate conditions, while others are climate dependent. Careful evaluation of candidate energy conservation measures for applicability and co

7、st efficiency is critical to building energy managers, engineers, contractors, and deci-sion makers in crafting and implementing successful energy conservation building retrofits. This paper presents a simu-lation based methodology for screening energy conservation technologies and measures for repr

8、esentative conditions (building type, climatic conditions, energy costs, etc.) The study demonstrates the feasibility of applying the method-ology using an example of heated and ventilated (not air-conditioned) industrial buildings for six selected energy conservation measures. A simple payback is c

9、alculated using electricity and gas savings throughout a year-round operation cycle. Also, a cost/saving analysis shows that application of internal load reducing technologies in non-air-conditioned facilities affect their thermal environment and has a significant impact on workers productivity. Con

10、sideration of workers productivity improvement as a component of operating cost reduction has a significant impact on the overall pay-back calculation results.INTRODUCTION In recent years, many new building system technologies have been developed with the promise of conserving energy. The energy sav

11、ing potentials of these technologies are often strongly dependent on some combination of climate, building use, envelope design, HVAC system design and plant design and their specific application. Some technologies (e.g., speed control using VFD, or replacement of lighting fixtures with more efficie

12、nt ones) can be evaluated using a simple spread-sheet-type calculation. Others require more sophisticated tools to account for multiple effects on the building envelop, thermal comfort and different building systems. Due to the difficulty of evaluating these new technologies through simple tradition

13、al Screening of Energy Efficient Technologies for Industrial Buildings RetrofitsAlexander M. Zhivov, PhD Richard Liesen, PhD Dan Fisher, PhDMember ASHRAE Fellow ASHRAEJon Hand, PhD Barry WilsonAlexander M. Zhivov is an operating agent of the IEA ECBCS Annex 46 and a program manager at the Energy Bra

14、nch of the U.S. Army Engineer Research and Development Center, Construction Engineering Research Laboratory, Champaign, IL. Richard Liesen is a senior research engineer at the Energy Branch of the U.S. Army Engineer Research and Development Center, Construction Engineering Research Laboratory, Champ

15、aign, IL. Dan Fisher is a professor of mechanical engineering at Oklahoma State University, Stillwater, OK. Jon Hand is a senior research fellow at the University of Strathclyde, Glasgow, Scotland. Barry Wilson is an engineer at GE Aviation, Cincinnati, OH.AB-10-0052010, American Society of Heating,

16、 Refrigerating and Air-Conditioning Engineers, Inc. (www.ashrae.org). Published in ASHRAE Transactions (2010, Vol. 116, Part 2). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAEs prior written permission.402

17、 ASHRAE Transactionsmethods, energy simulation software has emerged as the most efficient and effective method of evaluating the potential of a specific energy conservation technology applied to a specific building. Modern simulation tools such as EnergyPlus Strand, 2000 and ESP-r Hand, 2006 Clarke

18、2001 are well tailored to analyze these new energy conservation measures (ECM). In these modern simulation tools, models for many ECMs already exist or can be composed from elements within the tools. Expert users of these tools can readily assemble the building, system and plant data required to con

19、struct a building model. Typically this information, along with climate data, building use data, and typical system control strategies, is gleaned from on-site inspections, architectural drawings, and published equipment performance data. Once the basic model of the building has been constructed the

20、 expert simulation user can modify the simulation input to create model variants to evaluate each energy conservation measure of interest. ECMs can be evaluated one at a time or in combination with other measures. Budgetary rather than simulation program constraints usually limit the number of promi

21、sing technologies that can be evalu-ated for a particular project. The success of the process there-fore is strongly dependent on the ability of the design engineer to select from a list of 20 to 100 possible energy conservation measures that are applicable and the most cost efficient for a particul

22、ar building. This paper presents a simulation-based approach to the screening process that selects candidate technologies for a particular building. The first section of the paper describes the conceptual design of the simulation-based screening tool. This is followed by an account of several case s

23、tudies for an indus-trial building that illustrates the feasibility of the proposed approach and discusses the simulation tools required to effec-tively analyze and compare a large number of ECMs. Screen-ing of ECMs is conducted to develop a database with promising energy saving technologies and mea

24、sures for an interactive IT-tool under the International Energy Agency Energy Conservation in Buildings and Community Systems project - Annex 46 “Holistic Assessment Tool-kit on Energy Efficient Retrofit Measures for Government Buildings (EnERGo).” Annex 46This tool provides energy managers, design

25、engineers, and contractors with the knowledge required to select the best possible energy conservation measures for a building retrofit. The screening process does not consider every detail of a particular building, but accurately captures the effect of the most significant input parameters. The scr

26、eening process uses a building model that is representative of the particular segment of the building stock under consideration. Applica-tion of the screening results to the decision making process requires similarity in building construction type, system type, climate, and use. Annex 46 addresses s

27、ome representative government and public buildings, including offices, barracks and dormitories, industrial and maintenance facilities. This paper is limited only to discussion of ECMs related to indus-trial and maintenance facilities.THE BUILDING MODELSpecification of the baseline building model ha

28、s a signif-icant impact on the ranking of the ECMs. In general, a unique baseline model must be specified for buildings that differ significantly in envelope construction, ceiling height and use:Building Envelope Construction: The air-tightness, ther-mal mass and thermal resistance of the envelope m

29、ay have an impact on the screening process. The relative significance of these parameters, however, is largely determined by the building use. Often the heating and cooling load profile of industrial buildings is dominated by the internal gains rather than the envelope. Building Ceiling Height: The

30、ceiling height has a signif-icant impact on the degree of thermal stratification in the space. As a result, both system performance and the rel-ative ranking of system ECMs are impacted by this parameter. Building Use: Building use largely determines internal heat gains, infiltration rates, and requ

31、ired ventilation rates. The magnitude of the internal gains effectively shifts the relative importance of ECMs from heating to cooling. By reducing the heating load and increasing the cooling load, large internal gains associated with indus-trial processes minimize the impact of technologies that im

32、prove the performance of the heating system and maximize the performance of technologies that improve the performance of the cooling system. For industrial buildings, infiltration rates are often dominated by the frequent use of large overhead doors, and outside air requirements are often determined

33、 by the rate at which contaminants and toxins are released into the air. The industrial facility, shown in the Figure 1 below, was modeled as a 50 000 sq ft metal building with three work areas, a loading dock and an office. The three industrial work areas were designed to model a range of industria

34、l processes and include:1. A thermally intensive processing area (e.g., a heat treat shop)2. A ventilation intensive processing area (e.g., a plating shop)3. A light fabrication area (e.g., a welding shop)In addition, the model includes a shipping and receiving area with four large overhead doors an

35、d a typical office area. The zones are differentiated from one another primarily on the basis of their internal heat gains as shown in Table 1 below. Internal gains are scheduled on the basis of a two-shift operation. Industrial buildings often have significant cracks in the faade, low quality fenes

36、tration and large doors that are opened with some frequency. The base case model explicitly represents such leakage paths and the opening of doors and the assessments, at 1-minute intervals solves the air movement 2010, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.

37、(www.ashrae.org). Published in ASHRAE Transactions (2010, Vol. 116, Part 2). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAEs prior written permission.2010 ASHRAE 403within the zones accounting for current

38、weather conditions and possible imbalances in the mechanical ventilation system. To ensure both EnergyPlus and ESP-r were working with compatible assumptions about flow, the ESP-r predictions were exported to EnergyPlus as averaged hourly values of infiltration for each building zone and for each cl

39、imatic zone.Typical light industrial wall and roof constructions were used in modeling the building. The walls are insulated metal construction (R-4). Single pane windows were used in the work areas and double pane windows were used in the office areas. An 8-in. lightweight concrete block wall separ

40、ated the office area from the work areas. The roof was a standard built up bitumen roof and the main floor consisted of an 8-in concrete slab.The HVAC system configuration can have a significant impact on the relative effectiveness of an industrial building ECM. The rank order of a set of ECMs is hi

41、ghly dependent on the system type and its interaction with the space. Three space/system configuration are of particular importance:Ventilation vs. Air-Conditioning: Many industrial facili-ties in moderate climates have “heating only” systems and rely on mechanical ventilation to provide tolerable w

42、orking conditions during the cooling season. For these systems, ECMs that would otherwise reduce the cooling load or improve system efficiency have no effect on the buildings energy use since the ventilation fan operates on a set schedule without regard for the cooling load. Radiant vs. Convective H

43、eating: Because these two sys-tem types interact with the space and maintain thermal comfort differently, the relative effectiveness of a given ECM can change significantly depending on the domi-nant heat transfer mechanism of the system. For convec-tive systems, the degree of thermal stratification

44、 in the space is dependent on a number of parameters including diffuser location, characteristics of the diffuser jet and the configuration of the spaceespecially the ceiling height. Together, these parameters can affect the relative impact of system ECMs.Outside Air vs. Recirculation: The outside a

45、ir load can significantly alter the rank order of industrial building Table 1. Zone Area And Internal Heat GainesZoneAreaft2Light Heat GainW/ft2Equipment Heat GainW/ft2People(Total Number)Infiltrationach (m3/s)Office 5 000 1 0.5 10 0.5 (0.393289)Shipping Heating 72F62F (22C17C)6 a.m.1 a.m.; MF200 cf

46、m occupied0 cfm unoccupiedShipping and Receiving Heating 70F60F (21C16C) 6 a.m.1 a.m.; MF 3 achHigh Thermal Loads Heating 70F60F (21C16C) 6 a.m.1 a.m.; MF 3 achHigh Ventilation Loads Heating 70F60F (21C16C) 6 a.m.1 a.m.; MF 9 achLight Fabrication Loads Heating 70F60F (21C16C) 6 a.m.1 a.m.; MF 4 ach2

47、010, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (www.ashrae.org). Published in ASHRAE Transactions (2010, Vol. 116, Part 2). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASH

48、RAEs prior written permission.2010 ASHRAE 405The simple payback (SPB) metric was very easy to calcu-late as shown in the following equations. First the initial cost (IC) and change in maintenance cost (MC) of a technology were estimated based on current equipment and construction costs. To estimate

49、the electricity savings (ES) and gas savings (GS), average utility rates for each location were determined World Energy Overview, 2006. If productivity is included in the analysis, the increase in productive hours (PH) due to the ECM is multiplied by an average labor rate to estimate the annual savings due to increased productivity.and (3)Although the simple payback metric is very easy to imple-ment it may not provide an accurate representation of the results, due to the fact it does not take into account the time value of mon