ASHRAE transactions最新文献

{"title":"The Dependence of Water Heater Energy Factor on Deviations from Nominal Conditions.","authors":"William M Healy","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>An analytical study is carried out to assess the impact of corrections to nominal test conditions on the measured energy factor for residential water heaters. While test conditions are specified in the method of test, the difficulty in exactly achieiving these test conditions in the laboratory necessitates a computational approach to correct the results to nominal conditions. This paper examines the magnitude of those corrections for a range of water heaters of various fuel type, heating method, and size across a number of potential draw volumes during a 24 hour simulated use test. In making these corrections, a recovery efficiency and a standby heat loss coefficient are determined during the test; the effects of variations in those measured values on the resultant energy factor are discussed. Finally, the impact of tighter test tolerances on the variability of the energy factor is investigated to assist in evaluating the benefits of changing test conditions.</p>","PeriodicalId":91206,"journal":{"name":"ASHRAE transactions","volume":"123 Pt 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6506833/pdf/nihms923338.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37232760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance Monitoring of Chilled-Water Distribution Systems Using HVAC-Cx.","authors":"Natascha Milesi Ferretti,&nbsp;Michael A Galler,&nbsp;Steven T Bushby","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>In this research we develop, test, and demonstrate the newest extension of the software HVAC-Cx (NIST and CSTB 2014), an automated commissioning tool for detecting common mechanical faults and control errors in chilled-water distribution systems (loops). The commissioning process can improve occupant comfort, ensure the persistence of correct system operation, and reduce energy consumption. Automated tools support the process by decreasing the time and the skill level required to carry out necessary quality assurance measures, and as a result they enable more thorough testing of building heating, ventilating, and air-conditioning (HVAC) systems. This paper describes the algorithm, developed by National Institute of Standards and Technology (NIST), to analyze chilled-water loops and presents the results of a passive monitoring investigation using field data obtained from BACnet^® (ASHRAE 2016) controllers and presents field validation of the findings. The tool was successful in detecting faults in system operation in its first field implementation supporting the investigation phase through performance monitoring. Its findings led to a full energy retrocommissioning of the field site.</p>","PeriodicalId":91206,"journal":{"name":"ASHRAE transactions","volume":"123 Pt 2","pages":"53-63"},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5695709/pdf/nihms915382.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"35636019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing Effectiveness of Ceiling-Ventilated Mock Airborne Infection Isolation Room in Preventing Hospital-Acquired Influenza Transmission to Health Care Workers.","authors":"Deepthi Sharan Thatiparti,&nbsp;Urmila Ghia,&nbsp;Kenneth R Mead","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Exposure to airborne influenza (or <i>flu</i>) from a patient's cough and exhaled air causes potential flu virus transmission to the persons located nearby. Hospital-acquired influenza is a major airborne disease that occurs to health care workers (HCW). This paper examines the airflow patterns and influenza-infected cough aerosol transport behavior in a ceiling-ventilated mock airborne infection isolation room (AIIR) and its effectiveness in mitigating HCW's exposure to airborne infection. The computational fluid dynamics (CFD) analysis of the airflow patterns and the flu virus dispersal behavior in a mock AIIR is conducted using the room geometries and layout (room dimensions, bathroom dimensions and details, placement of vents and furniture), ventilation parameters (flow rates at the inlet and outlet vents, diffuser design, thermal sources, etc.), and pressurization corresponding to that of a traditional ceiling-mounted ventilation arrangement observed in existing hospitals. The measured data shows that ventilation rates for the AIIR are about 12 air changes per hour(ach). However, the numerical results reveals incomplete air mixing and that not all of the room air is changed 12 times per hour. Two life-sized breathing human models are used to simulate a source patient and a receiving HCW. A patient cough cycle is introduced into the simulation and the airborne infection dispersal is tracked in time using a multiphase flow simulation approach. The results reveal air recirculation regions that diminished the effect of air filtration and prolong the presence of flu-contaminated air at the HCW's zone. Immediately after the patient coughs (0.51 s), the cough velocity from the patient's mouth drives the cough aerosols toward the HCW standing next to patient's bed. Within 0.7 s, the HCW is at risk of acquiring the infectious influenza disease, as a portion of these aerosols are inhaled by the HCW. As time progresses (5 s), the aerosols eventually spread throughout the entire room, as they are carried by the AIIR airflow patterns. Subsequently, a portion of these aerosols are removed by the exhaust ventilation. However, the remaining cough aerosols reenter and recirculate in the HCW's zone until they are removed by the exhaust ventilation. The infectious aerosols become diluted in the HCW's region over a period of 10 s because of the fresh air supplied into the HCW's zone. The overall duration of influenza infection in the room (until the aerosol count is reduced to less than 0.16% of the total number of aerosols ejected from the patient's mouth) is recorded as approximately 20 s. With successive coughing events, a near-continuous exposure would be possible. Hence, the ceiling-ventilation arrangement of the mock AIIR creats an unfavorable environment to the HCW throughout his stay in the room, and the modeled AIIR ventilation is not effective in protecting the HCW from infectious cough aerosols. The CFD results suggest that the AIIR ceiling ven","PeriodicalId":91206,"journal":{"name":"ASHRAE transactions","volume":"122 2","pages":"35-46"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5438175/pdf/nihms854873.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"35015058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Energy Implications of In-Line Filtration in California","authors":"I. Walker","doi":"10.2172/1171747","DOIUrl":"https://doi.org/10.2172/1171747","url":null,"abstract":"Energy Implications of In-­‐Line Filtration in California Iain Walker, Darryl Dickerhoff, David Faulkner and Will Turner Environmental Energy Technologies Division February 2013","PeriodicalId":91206,"journal":{"name":"ASHRAE transactions","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2013-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68215140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of the Low-Energy Design Process and Energy Performance of the Zion National Park Visitor Center: Preprint","authors":"N. Long, P. Torcellini, S. Pless, R. Judkoff","doi":"10.2172/859326","DOIUrl":"https://doi.org/10.2172/859326","url":null,"abstract":"In line with the mission of the National Park Service, the Zion National Park Visitor Center was designed to use 70% less energy than a comparable visitor center built to Federal Energy Code 10 CFR 435 (DOE 1995). The authors and NFS staff used an integrated design process, including extensive simulations, to minimize the energy consumption. The result was a passive solar commercial building that has a good thermal envelope, daylighting, and natural ventilation. Passive downdraft cooltowers provide all the cooling. Two Trombe walls provide a significant amount of the heating. After two years of metering, the results show a net energy use intensity of 24.7 kBtu/ft2 (280.5 MJ/m 2 ) and a 67% energy cost saving. Low energy use and aggressive demand management result in an energy cost intensity of $0.43/ft 2 ($4.63/m 2 ). The paper discusses lessons learned related to the design process, daylighting, PV system, and HVAC system.","PeriodicalId":91206,"journal":{"name":"ASHRAE transactions","volume":"1 1","pages":"321-340"},"PeriodicalIF":0.0,"publicationDate":"2005-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68240059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efficacy of intermittent ventilation for providing acceptable indoor air quality.","authors":"M. Sherman","doi":"10.2172/834643","DOIUrl":"https://doi.org/10.2172/834643","url":null,"abstract":"Ventilation standards and guidelines typically treat ventilation as a constant and specify its value. In many circumstances a designer wishes to use intermittent ventilation, rather than constant ventilation, but there are no easy equivalencies available. This report develops a model of efficacy that allows one to calculate how much intermittent ventilation one needs to get the same indoor air quality as a the continuous value specified. We have found that there is a simple relationship between three dimensionless quantities: the temporal ventilation effectiveness (which we call the efficacy), the nominal turn-over and the under-ventilation fraction. This relationship allows the calculation of intermittent ventilation for a wide variety of parameters and conditions. We can use the relationship to define a critical time that separates the regime in which ventilation variations can be averaged over from the regime in which variable ventilation is of low effectiveness. We have found that ventilation load-shifting, temporary protection against poor outdoor air quality and dynamic ventilation strategies can be quite effective in low-density buildings such as single-family houses or office spaces. The results of this work enable ventilation standards and guidelines to allow this extra flexibility and still provide acceptable indoor air quality.","PeriodicalId":91206,"journal":{"name":"ASHRAE transactions","volume":"1 1","pages":"93-101"},"PeriodicalIF":0.0,"publicationDate":"2004-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68238580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of H∞ compensator to a plant with a large amount of changes in characteristics","authors":"Y. Yamakawa, M. Kotaki, T. Yamazaki, T. Matsuba, K. Kamimura, S. Kurosu","doi":"10.11499/SICEP.2004.0_70_3","DOIUrl":"https://doi.org/10.11499/SICEP.2004.0_70_3","url":null,"abstract":"This paper concerns an application of H∞ compensators that achieve stability for a plant with large changes in characteristics as well as adequate disturbance suppression and reference tracking properties. The complexity of a thermal system such as temperature control of air-conditioned space in buildings makes it extremely difficult to obtain an exact plant model to improve control performance. The parameters in the plant model vary greatly due to changes in the operating conditions. Thus, most plants are often approximated by a first-order lag plus a deadtime system. In a previous paper (Yamakawa et al. 2004), the H∞ compensator was easily designed for plants with a small range of perturbations (20%∼80%). Design problems for plants with a large range of perturbations (100%∼300%) present many headaches. For large values of perturbations, the control performance cannot be improved any more because the robust stability becomes severe and too conservative. Then classical measures of the stability margin have to be selected in place of robust stability. As a result, the H∞ compensator that does not exceed a prespecified degree of stability can be designed to achieve the desired control performance. It can be found that the H∞ compensator reduces to a fixed transfer function as the parameter variation increases. Finally, we investigate in simulation how the H∞ compensator designed for plants with a large amount of perturbations is somewhat similar to the conventional proportional-integral (PI) controller.","PeriodicalId":91206,"journal":{"name":"ASHRAE transactions","volume":"1 1","pages":"15-25"},"PeriodicalIF":0.0,"publicationDate":"2004-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64430809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating the potential of vortex-enhanced evaporator performance for refrigeration applications","authors":"M. C. Gentry, N. C. Dejong, A. Jacobi","doi":"10.1016/s0140-6701(97)85042-4","DOIUrl":"https://doi.org/10.1016/s0140-6701(97)85042-4","url":null,"abstract":"","PeriodicalId":91206,"journal":{"name":"ASHRAE transactions","volume":"102 1","pages":"361-366"},"PeriodicalIF":0.0,"publicationDate":"1996-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/s0140-6701(97)85042-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"55842706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The impact of surface reflectance on the thermal performance of roofs: an experimental study","authors":"E. Griggs, P. Shipp","doi":"10.2172/5222249","DOIUrl":"https://doi.org/10.2172/5222249","url":null,"abstract":"This is one of a series of reports to be published describing research, development, and demonstration activities in support of the National Program for Building Thermal Envelope Systems and Materials. The National Program involves several federal agencies and many other organizations in the public and private sectors who are addressing the national objective of decreasing energy wastes in the heating and cooling of buildings. Results described in this report are part of the National Program through delegation of management responsibilities for the DOE lead. 20 refs., 14 figs., 4 tabs.","PeriodicalId":91206,"journal":{"name":"ASHRAE transactions","volume":"94 1","pages":"1626-1642"},"PeriodicalIF":0.0,"publicationDate":"1988-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68228284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A computer model for simulation of absorption systems in flexible and modular form","authors":"G. Grossman, K. Gommed, D. Gadoth","doi":"10.2172/5242145","DOIUrl":"https://doi.org/10.2172/5242145","url":null,"abstract":"Developpement d'un modele de simulation par ordinateur qui permet de calculer en chaque point d'un systeme de refrigeration par absorption la temperature, le debit, la concentration, la pression et la fraction de vapeur. Le code de calcul est base sur les equations qui gouvernent les composants du systeme et sur les proprietes des fluides trouvees dans les bases de donnees. Le programme de calcul a ete teste avec succes sur des pompes a chaleur monoetagee, bietagee et sur des transformateurs de chaleur fonctionnant avec les fluides de travail suivants: LiBr−H 2 O, H 2 O−NH 3 , LiBr/H 2 O−NH 3 , LiBr/ZnBr 2 −CH 3 OH, LiNO 3 /KNO 3 /NaNO 3 −H 2 O","PeriodicalId":91206,"journal":{"name":"ASHRAE transactions","volume":"93 1","pages":"2389-2428"},"PeriodicalIF":0.0,"publicationDate":"1987-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68228355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}