1、4692 Devel opmen t and I rn plemen tat ion of HVAC-KBCD: A Knowledge-Based Expert System for Conceptual Design of HVAC buildings from 200,001 to 500,000 ft2 comprise 15%, while buildings above 500,000 ft*represent 1 1 % of the total floor space. From this information it is clear that KBES developmen
2、t should focus on office buildings above 25,000 f?. Designing such buildings requires much more HVAC typically 15% of the total construc- tion budget is dedicated to the HVAC chiller plant will not have any absorption or gas engine chiller, fuel and gas heating. Only electric heating allowed. Indivi
3、dual electricity billing is not Yes, it is not mandatory; consider all mandatory secondary systems No, it is not mandatory, Only WLHP allowed Finned tube radiators are not allowed out radiators Yes, perimeter systems will be with- No, perimeter systems will be with radiators Need 50% of cooling capa
4、city on Apply only 50%, 50% cooling Each chiller capacity in chiller plant Allow hybrid chiller plant (gas and electric) Apply both gas and electric chillers Apply 40%, 6O%, and 50% cooling capacity in chiller plant Apply only electric chillers Table 15. HVAC-KBCD Matching Matrix of Initiation Rules
5、 to Perimeter Secondary Systems w/ Primary Systems ASH RAE Transactions: Research 269 The ji!h rule (ElecBill-1) allows the user to select systems that can charge electrical usage to the tenant directly. Even though several packaged rooftop units can be designed in a way that will allow individual b
6、illing, WLHP has been selected as the only system that will provide this capability due to its flexibility. The sixth rule (Fin-tube-radl) allows the user to be consistent with the third rule (Climatic-1) considering the utilization of radiators or baseboard heaters in cold climates. The sixth rule
7、will not allow generation of solutions that are in conflict with the third rule. For example, if HDD 4,000 and the user elects not to allow perimeter baseboard heaters, the KBES will not generate a solution. This feature will encourage the user to be more aware of the air diffusion system if he/she
8、decides to use an overhead diffusion system for the perimeter zone. In order to override this restriction, the user must change the HDD to a value less than 4,000 (even though the local HDD may be greater than 4,000) and to disallow baseboard or radiators. The seventh rule (Chiller-1) allows the use
9、r to specify two chillers of equal size (where each chiller provides 50% of the chiller plant capacity), or two chillers of unequal size. The selection can be 40% or 60% of the chiller plant total cooling capacity. This strategy allows the user to optimize chiller plant operation where the smaller c
10、hiller (the 40% chiller) will run more efficiently at low-load condition compared to a 50% chiller. The 60%/40% split is considered to yield (as closely as possible) equal systems, which is good design practice from both a hydraulic and system reliability standpoint. The eighth rule (Chille-) allows
11、 the user to select only electric chillers or a hybrid chiller plant (electric and gas) as long as gas is available (rule 4). In some cases, the designer is reluctant to use gas-driven engine chillers due to reasons such as availability of service, professional preference, etc., even if gas is avail
12、able at the site. These rules have been found to be sufficient in order to initiate the process of synthesizing HVAC 9 Consumption For November-May For June-October Charge I $O.O5/kWh I $0.09/kWh I Monthly Standing Charge $100.00 I Gas: Available at $0.3 152lhherm. Heating degree-days: 2,259 (ASHRAE
13、-90.1 -1 999) Radiators or baseboard heaters are inadmissible (user constraint, due to moderate winter). No individual billing (developer constraint). Chiller plant will use two chillers of equal size (designer preference). Hybrid chiller plant (electric and gas) allowed (designer desires to explore
14、 this option). The designer would like to evaluate the following alter- natives: 1. Ten promising HVAC CHP 17 repre- sents two water-cooled centrifugal chillers; CHP 18 represents two water-cooled chillers, the first screw and the second centrifugal; and CHP 19 is identical to CHP 18 but with the op
15、erating sequence reversed. Total Maint. cost Annual $ 52,169 52,169 53,023 53,023 Table 16. Office Building 1-Results Sorted by Life-Cycle Cost Total Energy cost Annual $ 223,390 223,128 223,387 223,124 Secondary Systems Primary Systems .- Core 1 Core2 VAV-CI 1 VAV-C22 VAV-CI i VAV-C21 VAV-CI 1 VAV_
16、C22 -. Total First Chiller cost Plant Boiler Plant DHW $ CHP-IO BOP-FUEL DHW-ELE 2,683,940 CHP-IO BOP-FUEL DHW-ELE 2,693,409 CHP-21 BOP-FUEL DHW-ELE 2,703,784 Alt# 13 4 18 9 Perimeter 1-8 VAV-P 1 VAV-P 1 VAV-P 1 VAV-P 1 Life-Cycle cost $ 5.389.419 5,396,317 5,4 17,6 19 VAV-C11 I VAV-C21 1 CHP-21 I B
17、OP-FUEL I DHW-ELE 1 2,713,253 5,424,506 5,591,919 5,598,786 5.604.723 5,611,591 VAV-P2 VAV-P5 VAV-P2 36 VAV-P2 5,620,739 5,620,739 5,629,698 5,648,938 45 1 VAV-P5 5,648,938 53,023 I 255,845 5,657,897 VAV-P2 VAV-P 1 VAV-P 1 VAV-PI VAV-P 1 VAV-CI 1 VAV-C21 CHP-21 BOP-FUEL DHW-ELE 2,625,385 VAV-CI 1 VA
18、V-C22 CHP-I BOP-FUEL DHW-ELE 2,562,762 VAV-CI 1 VAV-C21 CHP-I BOP-FUEL DHW-ELE 2,572,232 VAV-CI 1 VAV-C22 CHP-19 BOP-FUEL DHW-ELE 2,582,606 VAV-CI 1 VAV-C21 CHP-19 BOP-FUEL DHW-ELE 2,592,076 VAV-C1 1 VAV-C22 CHP-20 BOP-FUEL DHW-ELE 2,703,784 46,266 269,713 46,266 269,448 47,120 269,377 47,120 269,11
19、2 53,023 256,528 53,023 256,263 47,120 285,927 47,120 285,927 47,120 286,256 47,974 284,481 47,974 284,481 47,974 284,810 52,169 266,617 52,169 266,352 46,266 295,538 5,665,091 5,671,959 ,690,022 5.696389 5,743,002 17 VAV-P 1 8 VAV-P 1 33 VAV-P2 42 VAV-P5 24 VAV-P2 32 VAV-P2 41 VAV-P5 23 VAVP2 12 VA
20、V-P 1 3 VAV-P 1 28 VAV-P2 5,749,870 5,764,643 5,764,643 5,777,343 5,778,675 5,778,675 5,791,375 5,813,829 5,820,696 5,830,776 ASHRAE Transactions: Research 271 Table 16. Office Building I-Results Sorted by Life-Cycle Cost (continued) - Life-Cycle cost $ 5,830,766 - 5,843,476 5,855,589 5,855,589 5,86
21、8,288 5,917,425 5,917,425 5,928,524 5,981,232 5,981,232 5,992,331 6,052,691 6,059,559 6,198,347 6,198,347 6,2 1 1,047 Alt# 37 Configurations - Codes Secondary Systems Primary Systems Perimeter 1- Chiller 8 Core1 Core2 Plant Boiler Plant DHW VAV-P5 VAV-CI2 VAV-C23 CHP-1 DHW-ELE VAVP2 VAV-C1 1 VAV-C21
22、 CHP-1 BOP-FUEL DHWELE 19 Total Total Maint. Energy cost cost Total First Cost Annual Annual $ $ $ 2,474,893 46,266 295,538 2,484,363 46,266 295,867 34 43 25 VAV-P2 VAV-P5 VAV-P2 VAV-P2 VAV-P5 VAV-P2 35 VAV-C 1 1 VAV-C22 CHP-19 BOP-FUEL DHW-ELE 2,494,738 47,120 295,190 VAV-C12 VAV-C23 CHP-19 DHW-ELE
23、 2,494,738 47,120 295,190 VAV-CI 1 VAV-C21 CHP-19 BOP-FUEL DHW-ELE 2,504,207 47,120 295,519 VAV-C1 1 VAV-C22 CHP-20 BOP-FUEL DHW-ELE 2,615,915 53,023 283,243 VAV-Cl2 VAV-C23 CHP-20 DHWELE 2,615,915 53,023 283,243 VAV-CI 1 VAV-C21 CHP-20 BOP-FUEL DHW-ELE 2,625,385 53,023 283,409 44 VAV-P2 VAVP5 VAV-P
24、2 VAV-PI VAV-PI 26 VAV-CI 1 VAV-C22 CHP-9 BOP-FUEL DHW-ELE 2,596,071 52,169 292,617 VAVC 12 VAVC23 CHP9 DHWELE 2,596,071 52,169 292,617 VAV-CI 1 VAV-C21 CHP-9 BOP-FUEL DHW-ELE 2,605,540 52,169 292,783 VAV-CI 1 VAV-C22 CHP-2 BOP-FUEL DHW-ELE 2,713,764 43,632 296,445 VAV-CI 1 VAV-C21 CHP2 BOP-FUEL DHW
25、-ELE 2,723.233 43,632 296.180 30 39 VAV-P2 VAV-P5 VAV-P2 21 VAV-CI 1 VAV-C22 CHP-2 BOP-FUEL DHW-ELE 2,625,895 43,632 320,230 VAV-CI2 VAV-C23 CHP-2 DHW-ELE 2,625,895 43,632 320,230 VAV-CI 1 VAV-C21 CHP2 BOP-FUEL DHW-ELE 2,635,365 43,632 320,559 11 2 29 38 20 Solutions 9, 4, 18, 13, 27, 22, 36, 45, 31
26、, and 40 are the design alternatives with the lowest annual energy cost. The lowest energy cost solution is a gas-driven chiller and gas zone heating (in place of electricity, which was shown previously to be the lowest first cost solution). The availability of cheap natural gas and a constant elect
27、rical demand charge (regard- less ofthe time ofday and season) make the gas-cooling option the most energy cost-effective system for this building. All the ten solutions with the lowest energy cost utilize a hybrid chiller plant, where the gas-driven chiller is always the lead chiller and the electr
28、ic chiller is the second. The second elec- tric chiller can be a water-cooled Centrifugal chiller or screw (CHP 21 and CHP 10, respectively). The solutions with CHP 21 have a low operating cost since the centrifugal chiller is more efficient. However, the difference is insignificant (less then $5),
29、demonstrating that the gas-driven chiller does the majority of cooling. The all-electric chiller plant, shown as solution number 5 with CHP 17, demonstrates that for all- electric chiller plants, two centrifugal chillers are the most energy cost-effective. LCC analysis incorporates first cost as wel
30、l as annual energy and maintenance costs into one value representing the owning and operating cost for the systems lifetime. LCC anal- ysis demonstrates that from the ten selected systems, six systems (13,4, 18,9,3 1, and 40) utilize a hybrid chiller plant and four systems utilize all-electric chill
31、er plants (15,6,14,5). Most ofthe systems (the first eight systems) utilize natural gas for heating and only the last two systems use electricity for heating. Another interesting finding is that the most cost- effective solution from an LCC standpoint utilizes a hybrid 272 - I I Figure 3 OBce Buildi
32、ng I-life-cycle, $first, and energy costs-all 45 solutions. chiller plant, gas heating (with hot water) for the perimeter zones, air-handling units, and electric zone reheat for the core in the upper floor. Figure 3 demonstrates how LCC, first, and annual energy costs vary among the 45 design config
33、urations. ASHRAE Transactions: Research SUMMARY Sociey of Heating, Refrigeration and Air-conditioning Engineers, Inc. ASHRAE. 2000. ASHRAE Handbook-Systems and Equip- ment. Atlanta: American Society of Heating, Refrigera- tion and Air-conditioning Engineers, Inc. ASHRAE. 200 1 a. ANSI/ASHRAE/IESNA S
34、tandard 90.1 - 1999, 2001, Energy Standard for Buildings Except Low Rise Residential Buildings. Atlanta: American Society of Heating, Refrigeration and Air-conditioning Engi- neers, Inc. ASHRAE. 200 1 b. ASHRAE Handbook-Fundamentals. Atlanta: American Society of Heating, Refrigeration and Air-condit
35、ioning Engineers, Inc. Bell, A.A. 2000. HVAC Equations, Data, and Rules of Thumb. New York: McGraw-Hill. EIA. 1995. Energy Information Agency, Washington DC. Gause, J.A. 1998. Ofice Development Handbook, 2nd ed. Washington, D.C.: Urban Land Institute. Knebel, D.E. 1983. Simpli3ed Energy Analysis Usi
36、ng Modi- jed Bin Methods. Atlanta: American Society of Heat- ing, Refrigeration and Air-conditioning Engineers, Inc. Maor, I. 2002. Conceptual design and selection of HVAC&R systems by combining knowledge based expert systems with building energy simulation program. Ph.D thesis, Department of Civil,
37、 Architectural and Environmental Engineering, Drexel University, Pennsylvania. Maor, I., and T.A. Reddy. 2003. Literature review of artificial intelligence and knowledge-based expert systems in engineering and HVAC&R design. ASHRAE Transac- tions 109( 1). Maor, I., and T.A. Reddy. 2004. Development
38、and Imple- mentation of HVAC-KBCD: A knowledge-based expert system for conceptual design of HVAC&R systems, Part 1 : General framework. ASHRAE Transactions 1 1 O( 1). Means. 2002a. Means Mechanical Cost Data. Kingston, Mass.: R.S Means Company Inc. Means. 2002b. Means Maintenance and Repair Cost Dat
39、a. Kingston, Mass.: R.S Means Company Inc. Sciubba, E., and R. Melli. 1998. Artijicial Intelligence in Thermal Systems Design: Concepts and Applications. Commack, NY Nova Science Publishers. VisualDOE 3.0 Program documentation. 2002. Eley and Associates, San Francisco, Calif. White, J.R., ed. 1993.
40、The Ofice Buildings-From Concept to Investment Realig. Chicago, Ill.: Counselors of Real Estate. The companion paper (Maor and Reddy 2004) addressed the HVAC&R conceptual design problem (or the selection of the HVAC&R design concept) and the limitations of current conceptual design procedures. It fo
41、cused on the elicitation and development of methodologies and knowledge to be incorpo- rated and represented in a DES. In parallel with knowledge elicitation and generation, a commercial KBES shell was selected as the HVAC-KBCD prototype. This software was used to demonstrate the efficacy of the met
42、hods developed. This paper is the demonstration of the concepts and meth- odologies described previously using the prototype -ES. One case study involving the conceptual design of an office building was selected for the demonstration. It served to demonstrate how the KBES can be employed as a design
43、 assis- tant to generate and evaluate a large number of design alter- natives to select promising HVAC&R systems. The HVAC- KBCD can be easily expanded to handle other building appli- cations, such as schools, hotels, retail stores, etc. The ultimate goal is to provide the building designer a tool w
44、hereby, upon simply specifiing certain initiation data, the KBES automat- ically synthesizes and evaluates the feasible solutions by sort- ing them according to a pre-specified criterion (such as LCC). As in the office building application, every other application has its own characteristics in term
45、s of architecture, operating schedules, typical cooling and heating loads, applicable HVAC&R systems, etc. All these characteristics can be explored and incorporated into the HVAC-KBCD, resulting in new sets of applicable HVAC&R systems and application- specific heuristics. ACKNOWLEDGMENTS We would
46、like to acknowledge insightful comments and advice during this study from Profs. Young Cho, James Mitch- ell, Il-Ye01 Song, and Rich Weggell fiom Drexel University and Prof. Gershon Grossman from the Technion, Israel. Comments by anonymous reviewers to improve the presenta- tion of this paper are ap
47、preciated. REFERENCES ASHRAE. 1999a. ANSI/ASHRAE/IESNA Standard 90.1- 1999, 1999, Energy Standard for Buildings Except Low Rise Residential Buildings. Atlanta: American Society of Heating, Refrigeration and Air-conditioning Engi- neers, Inc. Winklemann, F.C., et al. 1993. DOE-2 Supplement, version 2. IE. Berkeley, Calif.: Lawrence Berkeley National ASHRAE. 1999b. ANSI/ASHRAE/IESNA Standard 90. I- 1999, 1999, 90. I Users Manual. Atlanta: American Laboratories. ASHRAE Transactions: Research 273
