HVAC&R Research最新文献

{"title":"Experimental study on the heat recovery characteristic of a plate heat pipe heat exchanger in room ventilation","authors":"Y. Diao, Ji Zhang, W. Yu, Yaohua Zhao","doi":"10.1080/10789669.2014.945852","DOIUrl":"https://doi.org/10.1080/10789669.2014.945852","url":null,"abstract":"A plate heat pipe heat exchanger for use in a room ventilation system to cool or heat outdoor fresh air was designed in this study. One fresh air duct and one exhaust air duct were joined with the heat pipe heat exchanger to study the thermal performance of the thermal recovery system. A ratio of 1 for air volume flow rate between fresh and exhaust air was used to investigate the heat recovery effectiveness and the change in fresh air temperature. The fresh air temperature in the inlet duct was controlled in the range of 27 to 40°C under summer simulation conditions and in the range of 2 to 15°C under winter simulation conditions, whereas the temperature of exhaust air was controlled at approximately 24 and 18 C to simulate summer and winter conditions, respectively. The experimental results show that the temperature variations of fresh and exhaust air increase with increasing inlet fresh air temperature under summer conditions but decrease with increasing inlet temperature of fresh air under winter conditions. The maximum heat recovery effectiveness of the plate heat pipe heat exchanger was 58% in summer and 62% in winter. The change in effectiveness is moderate with different vacuum levels. At a vacuum of 1 × 10−3 Pa, the maximum effectiveness occurred when the filling ratio was 1:3. The experimental results showed that the heat pipe heat exchanger gained a high efficiency of heat recovery with low flow resistance. The energy conservation effect of this heat-pipe heat exchanger was evident.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"1 1","pages":"828 - 835"},"PeriodicalIF":0.0,"publicationDate":"2014-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86819254","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":"Bioclimatic housing design to desert architecture: A case study of Ghadames, Libya","authors":"Jamal Alabid, A. Taki","doi":"10.1080/10789669.2014.953872","DOIUrl":"https://doi.org/10.1080/10789669.2014.953872","url":null,"abstract":"This article assesses the most common architectural and environmental strategies in Ghadames housing in Libya. Preliminary data were collected through field surveys undertaken in July 2013, the hottest and driest season in Ghadames. The surveys investigated the indoor thermal environment and efficiency of energy use in Ghadames housing. The actual mean vote scale was used to investigate occupants’ thermal feeling coupled with recording physical environment and also actual measurements of a number of existing houses. Additionally, objective surveys were conducted to (a) verify the subjective data, (b) provide an overall view of the residents’ life style in the old town, and (c) understand the most significant techniques employed in old dwellings. The subjective survey “questionnaire” distributed among nine new and eight old houses shows that the majority of respondents is satisfied with the number of architectural issues in modern housing design. This general satisfaction excludes the inherited identity of the traditional architecture embedded within the society. On the other hand, occupants are more satisfied with old buildings in regard to indoor environmental conditions, energy consumption, and construction materials. The occupants of old houses expressed their thermal satisfaction with the indoor comfort conditions, but the predicted mean vote, based on measurements and ISO 7730, implied discomfort (hot).The survey also carried out interviews with a number of locals, underlining their personal impressions and preference toward the change of the existing built environment. Findings indicate that, occupants’ satisfaction and perception toward the built environment have not been achieved in new housing developments of Ghadames owing to the lack of understanding of the sociocultural needs of the local community. In addition, a 3D digital model was created for the old town and imparted a full understanding of the building dynamics and physics, explicating the complexity of the compactness of its urban morphologies. The results also showed subjects were feeling neutral to slightly warm in old buildings even when indoor air temperatures reached 32°C.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"4 1","pages":"760 - 769"},"PeriodicalIF":0.0,"publicationDate":"2014-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75316301","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":"Inverse design of aircraft cabin environment by coupling artificial neural network and genetic algorithm","authors":"T. Zhang, X. You","doi":"10.1080/10789669.2014.950895","DOIUrl":"https://doi.org/10.1080/10789669.2014.950895","url":null,"abstract":"An inverse design method is proposed to achieve the pre-set control objectives of the aircraft cabin environment. The method combines the artificial neural network and the genetic algorithm, and the training and testing data of the artificial neural network is obtained by computational fluid dynamics analysis. Both of the thermal comfort and energy consumption are considered in the inverse design. The artificial neural network is used to identify the relationship between the thermal comfort and the air supply parameters (inlet velocity magnitude and angle, inlet air temperature). The genetic algorithm coupled with the well-trained artificial neural network is used to design the aircraft cabin environment. Numerical results show that the Bayesian regularization algorithm is proved to have better generalization capability than the other training algorithms for the artificial neural network. The increase of training data quantity improves the generalization capability of the artificial neural network, while it spends more simulation time. A computational fluid dynamics database with 60 datasets is shown to be suitable to the present inverse design, and the testing error of the artificial neural network is below 8.2%. Several groups of optimal air supply parameters are found with different trade-offs between the thermal comfort and energy consumption. The best solution of thermal comfort, i.e., the percentage of zone with |PMV| >0.5 in all cabin control domains, is less than 7.8%.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"77 1","pages":"836 - 843"},"PeriodicalIF":0.0,"publicationDate":"2014-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83876603","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":"Field survey of air conditioner temperature settings in a hot, dry climate (Oman)","authors":"Noor Hanita Abdul Majid, Nozomi Takagi, S. Hokoi, S. Ekasiwi, Tomoko Uno","doi":"10.1080/10789669.2014.953845","DOIUrl":"https://doi.org/10.1080/10789669.2014.953845","url":null,"abstract":"In conventional air-conditioning design, the comfortable range of temperatures is between 25°C and 27°C with relative humidity levels of 40% to 60%; these numbers vary only slightly based on a person's race and country. Several studies in tropical climates show that the observed thermal comfort requirement often does not agree with those obtained based on experiments, which have mainly used North American subjects. However, there is no consistent rationale that explains why comfort requirements are different in hot climates, suggesting that more surveys on thermal comfort may be needed in the tropics. In Asia, there has recently been a rapid and widespread diffusion of air conditioners; therefore, a survey was conducted to clarify what temperature and humidity level people in Asian countries prefer in order to feel comfortable. Following that research, this article presents the results of a questionnaire survey on the use of air conditioners in houses in hot, dry climates. Nizwa and Rustak, Oman, characterized by the hot, arid climate of the Arabian Peninsula, were chosen as survey areas. The questionnaire survey was distributed to students of Nizwa University. Questions were asked about the duration of air-conditioner use and preferred air-conditioner temperature settings. To determine how respondents felt about their indoor environment, questions were also asked about the thermal sensations that were experienced while using the air conditioner. In both cities, the mean operating time of the air conditioner was very long. The respondents reported selecting a low temperature setting while sleeping, despite the fact that many of them reported that they were cold while sleeping. Ninety percent of respondents reported a cold, cool, or neutral thermal sensation while using the air conditioner without feeling discomfort.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"1 1","pages":"751 - 759"},"PeriodicalIF":0.0,"publicationDate":"2014-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74773750","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":"Passive pre-cooling potential for reducing building air-conditioning loads in hot climates","authors":"H. Chaudhry, B. Hughes","doi":"10.1080/10789669.2014.952976","DOIUrl":"https://doi.org/10.1080/10789669.2014.952976","url":null,"abstract":"The passive airside cooling capability of heat pipes operating under high-temperature natural ventilation airstreams was investigated in this study. Pure water was used as the internal working fluid to ensure the system remained sustainable in its operation. The physical domain included 19 cylindrical copper heat pipes assembled in a systematic vertical arrangement. Using the monthly temperature data of Doha, Qatar, as a case-study reference, the efficiency of the heat pipe model was analyzed at fixed inlet air velocities of 1 and 2.3 m/s. At a source temperature of 314 K, the results showed a maximum temperature reduction of 3.8 K for an external air velocity of 1 m/s. A cooling load of 976 W was achieved, indicating a heat pipe effectiveness of 6.4% when the velocity was increased to 2.3 m/s. Wind tunnel experimental testing was conducted to validate the findings. A good correlation was observed between the two techniques with error variations of 10% for velocity and 28% for temperature. The present work identified the potential of sustainable pre-cooling using heat pipes in natural ventilation airstreams for regions with hot and dry climatic conditions. The concept is currently under intellectual property protection (GB1321709.6).","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"1 1","pages":"738 - 750"},"PeriodicalIF":0.0,"publicationDate":"2014-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89982673","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":"Fin design for an evaporator with small diameter microgroove tubes","authors":"Haitao Hu, Jingdan Gao, G. Ding, Yi-feng Gao, J. Song","doi":"10.1080/10789669.2014.936796","DOIUrl":"https://doi.org/10.1080/10789669.2014.936796","url":null,"abstract":"The application of fin-and-tube heat exchangers with small diameter microgroove tubes in room air conditioners has rapidly increased recently, and fins suitable for such heat exchangers should be developed. In the present study, a louver fin suitable for the evaporator with small diameter microgroove tubes was designed by applying computational fluid dynamics method, and the performance of the optimized and existing louver fins were experimentally investigated. Experimental results show that water bridge occurs at the bottom of the optimized fins for small diameter tubes, which is not the same as that for larger diameter tubes; for the fins of the evaporator with small diameter tubes, the increase of the fin pitch leads to the decrease of Colburn j factors. Based on the experimental data, a correlation of the Colburn j factor was developed to predict the heat transfer rate of the evaporator with small diameter microgroove tubes, and agrees with 85% of the experimental data within a deviation of ±20%.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"91 1","pages":"790 - 797"},"PeriodicalIF":0.0,"publicationDate":"2014-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80519934","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":"Performance experiment of all fresh air-handling unit with high sub-cooling degree and year-round exergy analysis","authors":"Zhongbin Zhang, Ya-Ping Pan, Hu Huang, Qing Jiang","doi":"10.1080/10789669.2014.939059","DOIUrl":"https://doi.org/10.1080/10789669.2014.939059","url":null,"abstract":"In this article, an all fresh air-handling unit with high sub-cooling degree is presented. In this unit, refrigerant flows through the high-pressure liquid receiver before it goes through the sub-cooler so as to ensure sufficient sub-cooling degree. Based on the experimental comparison between this unit and conventional unit, coupling relationships between condensing temperatures and sub-cooling degrees of these two units are worked out and analyzed. Experimental results and exergy analysis show that, sub-cooling degree drops with the decrease of condensing temperature, and sub-cooling degree of the designed unit is kept over 7°C when the sub-cooling degree of the conventional unit is only close to 0°C. Furthermore, a method of year-round exergy calculation is presented and applied in calculating and analyzing the year-round exergy of the all fresh air-handling unit. Calculation and analysis show that the all fresh air-handling unit designed and investigated in this article has a year-round exergy efficiency of 28.38%, which is 3.17% higher than that of the conventional unit without high sub-cooling degree.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"262 1","pages":"810 - 818"},"PeriodicalIF":0.0,"publicationDate":"2014-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76631093","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":"Measurement of particle deposition rates in a commercial aircraft cabin","authors":"R. Powell, B. Jones, M. Hosni","doi":"10.1080/10789669.2014.945851","DOIUrl":"https://doi.org/10.1080/10789669.2014.945851","url":null,"abstract":"Thousands of people travel by air every day. In 2011, 730 million people traveled on commercial aircraft domestically (BTS 2012). These passengers are confined to a very high-occupant density space for extended periods of time, sometimes over 15 h or more, for international flights. This large volume of travelers, combined with their time spent in close proximity of each other, during flights increases the potential for transmitting diseases, such as severe acute respiratory syndrome (SARS), tuberculosis, swine influenza (H1N1), and avian influenza (H5N1). Consequently, a common concern during commercial flight is disease transfer among passengers. Airborne pathogens travel throughout aircraft cabins much as airborne particles would. To study how these airborne diseases travel, particles were released into a Boeing 767 aircraft cabin mockup, and the particle deposition rates over a variety of locations were measured. In addition to varying the location of measurements, the surface orientation for measurements was changed between horizontal and vertical configurations. The number of particles that deposited onto a clear tape for each location was optically counted using a photographic type microscope. The microscope limited the particle detection size to particles with diameters greater than 3.0 μm. The particle deposition measurements were then compared to previous air concentration measurements taken in the same mockup aircraft cabin. It was found that the surface orientation played a significant role in particle deposition. Nearly a factor of ten differences in particle counts was observed between the vertical and horizontal surface orientations. In addition, the deposition trend in the mockup cabin, left to right for horizontal orientation, reversed when the surface orientation was changed.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"20 1","pages":"770 - 779"},"PeriodicalIF":0.0,"publicationDate":"2014-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79105215","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":"Indoor environmental quality and infection control in surgery rooms: Code requirements vs. performance motivation. A critical review","authors":"Eduard Cubi Montanya, Jaume Salom Tormo, Núria Garrido Soriano","doi":"10.1080/10789669.2014.929423","DOIUrl":"https://doi.org/10.1080/10789669.2014.929423","url":null,"abstract":"Surgery rooms are a space type with particularly stringent indoor environmental quality (IEQ) requirements (large airflow rates and narrow comfort windows), which translate into high energy use. Due to the unclear IEQ and infection control requirements for surgery rooms in Spain, these spaces are often designed and operated 24 hours per day and 7 days per week, to meet the most stringent recommendations (not only the requirements) in the available standards and guidelines. This paper critically reviews the Spanish mandatory requirements for surgery rooms by comparing them against their performance motivation and other international standards. Regulatory ambiguities and code-compliant energy efficiency opportunities are identified. The requirements and recommendations in the standards included in this review differ in their magnitude (particularly the airflow requirements), but are similar in their prescriptive nature. This paper identifies the performance goals associated to the prescriptive requirements, and proposes a method to adjust system operation (outdoor airflow rate, total supply air, indoor air temperature, and indoor air relative humidity) to meet IEQ performance goals while reducing energy use. Further work is required to define operation infection control requirements for the different surgery types and enable a performance based control strategy based on real time particle concentration monitoring.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"34 1","pages":"643 - 654"},"PeriodicalIF":0.0,"publicationDate":"2014-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73536353","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":"New HVAC&R Research journal publication guidelines clarify expanded range of acceptable topics","authors":"Mary E. Collins Baugher","doi":"10.1080/10789669.2014.930604","DOIUrl":"https://doi.org/10.1080/10789669.2014.930604","url":null,"abstract":"In an effort to align the breadth of the journal’s topics with ASHRAE’s vision, members of the editorial board of the HVAC&R Research Journal (ASHRAE’s International Journal for Research) have revised the scope of topics that are suitable for publication in the journal. This modification is an adaption to changes in the field and will enable us to more fully meet the information needs of our growing readership. HVAC&R Research offers comprehensive reporting of original research in science and technology related to the stationary and mobile built environment, including:","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"2 1","pages":"593 - 593"},"PeriodicalIF":0.0,"publicationDate":"2014-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86117323","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}