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《建筑热能通风空调》2017,(8)
本文对比了个性化送风与传统的空调送风形式,个性化送风系统改善了人体热舒适及室内空气品质,人们获得了符合自己需要的个性化环境,极大提高了每一个人对其微环境的满意度。总结了国内外有关个性化送风在人体热舒适性、可吸入空气品质等方面的研究评价,分析了个性化送风系统研究的发展趋势。 相似文献
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地板个性化送风能够改善工作区微环境的空气品质和热舒适性,其送风温度较传统空调系统高,有较大的节能潜力。对送风采用冷冻除湿和转轮除湿时,节能与否或者节能程度大小分别取决于再热量和再生热量及再生风机能耗。本文中,利用能耗模拟分析软件Energyplus分别模拟计算了在中国各气候区使用混合通风、冷冻除湿的地板个性化送风及转轮除湿的地板个性化送风系统时,各系统的年能耗,并进行了比较分析,得出地板个性化送风系统在中国各气候区的能耗特性。 相似文献
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探讨了架空地板送风系统的工作原理和特点,分析了该系统的送风静压层和送风特性,并从这种送风特性出发,综述了架空地板送风系统在室内空气品质、热舒适性和节能等方面的特点。通过分析,得出架空地板送风系统能够减小空气龄,提高换气效率和通风效率,显著改善室内空气品质;在热舒适方面,架空地板送风系统可以通过使用者调节出风方向和风量达到热舒适:在能耗方面,架空地板送风系统由于仅需维持工作区环境参数,使得送风量和风机压头减小,制冷机效率提高,在风机能耗和冷热源能耗上有着显著的经济效益。最后得出了架空地板送风系统将被广泛应用的结论。 相似文献
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地板送风空调系统因其在热舒适、室内空气品质和节能性等方面的诸多优点,在我国逐渐得到研究和应用。本文采用CFD建立地板送风静压箱模型,模拟分析了静压箱地板送风系统静压箱高度、进风口位置及形状对静压箱送风均匀性的影响,可为工程设计提供参考。 相似文献
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The potential for improving occupants’ thermal comfort with personalized ventilation (PV) system combined with under-floor air distribution (UFAD) system was explored through human response study. The hypothesis was that cold draught at feet can be reduced when relatively warm air is supplied by UFAD system and uncomfortable sensation as “warm head” can be reduced by the PV system providing cool and fresh outdoor air at the facial level. A study with 30 human subjects was conducted in a Field Environmental Chamber. The chamber was served by two dedicated systems – a primary air handling unit (AHU) for 100% outdoor air that is supplied through the PV air terminal devices and a secondary AHU for 100% recirculated air that is supplied through UFAD outlets. Responses of the subjects to the PV-UFAD system were collected at various room air and PV air temperature combinations. The analyses of the results obtained reveal improved acceptability of perceived air quality and improved thermal sensation with PV-UFAD in comparison with the reference case of UFAD alone or mixing ventilation with ceiling supply diffuser. The local thermal sensation at the feet was also improved when warmer UFAD supply air temperature was adopted in the PV-UFAD system. 相似文献
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The effect of personalized ventilation (PV) on people's health, comfort, and performance in a warm and humid environment (26 and 28°C at 70% relative humidity) was studied and compared with their responses in a comfortable environment (23°C and 40% relative humidity). Thirty subjects participated in five 4‐h experiments in a climate chamber. Under the conditions with PV, the subjects were able to control the rate and direction of the supplied personalized flow of clean air. Subjective responses were collected through questionnaires. During all exposures, the subjects were occupied with tasks used to assess their performance. Objective measures of tear film stability, concentration of stress biomarkers in saliva, and eye blinking rate were taken. Using PV significantly improved the perceived air quality (PAQ) and thermal sensation and decreased the intensity of Sick Building Syndrome (SBS) symptoms to those prevailing in a comfortable room environment without PV. Self‐estimated and objectively measured performance was improved. Increasing the temperature and relative humidity, but not the use of PV, significantly decreased tear film quality and the concentration of salivary alpha‐amylase, indicating lower mental arousal and alertness. The use of PV improved tear film stability as compared to that in a warm environment without PV. 相似文献
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This paper presents an investigation of the design and performance characteristics of personalized ventilation (PV) systems that, in combination with general ventilation, deliver high quality air to the breathing zone (BZ) with no more clean air supply than indicated by ANSI/ASHRAE 62.1-2004, while satisfying acceptable ergonomic and aesthetic considerations. Under these conditions, the energy used for conditioning the clean air will not exceed that of a conventional ventilation system. We introduce a novel PV nozzle that achieves high BZ air quality with a small fraction of the clean air indicated by the ANSI/ASHRAE Standard. Tracer gas experimental results presented in this paper demonstrate the advantages of the novel nozzle relative to conventional PV nozzles. The results show that, at a PV clean air supply of only 2.4 l/s, the new nozzle achieves a BZ ventilation effectiveness close to 7 versus less than 2 for a conventional nozzle delivering the same amount of clean air. A companion paper presents a computational analysis of the same concept, validated against the experimental results of the present paper. 相似文献
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The performance of the novel “ductless” personalized ventilation in conjunction with displacement ventilation (DV) was compared with the performance of DV alone under realistic conditions involving disturbances due to walking of one or two persons. An office room with two workstations was arranged in a full-scale test room. Two thermal manikins were used as sedentary occupants at the workstations. Two pollution sources, namely exhaled air by one of the manikins and passive pollution on the table in front of the same manikin were simulated. The performance of the ventilation systems was evaluated with regard to the quality of inhaled air and thermal comfort of the seated “occupants”. The walking person(s) caused mixing of the clean and cool air near the floor with the polluted and warmer air at higher levels and disturbed the displacement principle which resulted in a decrease of the inhaled air quality. The performance of the “ductless” PV under the tested conditions was better as opposed to DV alone. Thus in practice the “ductless” PV will be superior to DV alone as regards perceived quality of inhaled air. The location of a walking person was found to be important. Person(s) walking close to the displacement diffuser will cause greater disturbance. 相似文献
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Personalized ventilation (PV) is an individually controlled air distribution system aimed at improving the quality of inhaled air and the thermal comfort of each occupant. Numerous studies have shown that PV in comparison with traditional mechanical ventilation systems may improve occupants’ health, inhaled air quality, thermal comfort, and self-estimated productivity. Little is known about its energy performance.In this study, the energy consumption of a personalized ventilation system introduced in an office building located in a hot and humid climate (Singapore) has been investigated by means of simulations with the empirically tested IDA-ICE software. The results reveal that the use of PV may reduce the energy consumption substantially (up to 51%) compared to mixing ventilation when the following control strategies are applied: (a) reducing the airflow rate due to the higher ventilation effectiveness of PV; (b) increasing the maximum allowed room air temperature due to PV capacity to control the microclimate; (c) supplying the outdoor air only when the occupant is at the desk. The strategy to control the supply air temperature does not affect the energy consumption in a hot and humid climate. 相似文献
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This study investigates the performance of two systems: personalized ventilation (PV) and ductless personalized ventilation (DPV). Even though the literature indicates a compelling performance of PV, it is not often used in practice due to its impracticality. Therefore, the present study assesses the possibility of replacing the inflexible PV with DPV in office rooms equipped with displacement ventilation (DV) in the summer season. Numerical simulations were utilized to evaluate the inhaled concentration of pollutants when PV and DPV are used. The systems were compared in a simulated office with two occupants: a susceptible occupant and a source occupant. Three types of pollution were simulated: exhaled infectious air, dermally emitted contamination, and room contamination from a passive source. Results indicated that PV improved the inhaled air quality regardless of the location of the pollution source; a higher PV supply flow rate positively impacted the inhaled air quality. Contrarily, the performance of DPV was highly sensitive to the source location and the personalized flow rate. A higher DPV flow rate tends to decrease the inhaled air quality due to increased mixing of pollutants in the room. Moreover, both systems achieved better results when the personalized system of the source occupant was switched off. 相似文献
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Personalized ventilation (PV) system in conjunction with total ventilation system can provide cleaner inhaled air for the user. Concerns still exist about whether the normally protecting PV device, on the other hand, facilitates the dispersion of infectious agents generated by its user. In this article, two types of PV systems with upward supplied fresh air, namely a chair‐based PV and one kind of desk‐mounted PV systems, when combined with mixing ventilation (MV) and displacement ventilation (DV) systems, are investigated using simulation method with regard to their impacts on co‐occupant's exposure to the exhaled droplet nuclei generated by the infected PV user. Simulation results of tracer gas and particles with aerodynamic diameter of 1, 5, and 10 μm from exhaled air show that, when only the infected person uses a PV, the different PV air supplying directions present very different impacts on the co‐occupant's intake under DV, while no apparent differences can be observed under MV. The findings demonstrate that better inhaled air quality can always be achieved under DV when the adopted PV system can deliver conditioned fresh air in the same direction with the mainly upward airflow patterns of DV. 相似文献
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Thuan-Quoc Thach Dhiya Mahirah Charlotte Sauter Adam Charles Roberts Gerard Dunleavy Nuraini Nazeha Yuri Rykov Yichi Zhang George I. Christopoulos Chee-Kiong Soh Josip Car 《Indoor air》2020,30(6):1166-1177
Indoor environmental quality (IEQ) is a general indicator of the quality of conditions inside a building. We investigated associations of perceived IEQ including air quality, thermal comfort, noise, and light quality with stress at work and the extent to which workplace location modifies these associations. We recruited 464 full-time workers from four companies in Singapore. Data on socio-demographic characteristics, lifestyle/health-related factors, and workplace factors were collected through self-administered questionnaires. Perceived IEQ satisfaction scores of all four factors were collected using the validated OFFICAIR questionnaire. We fitted a logistic regression model to assess associations between each perceived IEQ score and stress at work, adjusting for potential confounders. The odds ratio for stress at work associated with a 1-unit increase in perceived air quality score was 0.88 (0.82-0.94), 0.89 (0.82-0.97) for thermal comfort, 0.93 (0.87-0.98) for noise, and 0.88 (0.82-0.94) for light quality. Significant associations were found in office and control rooms for all four perceived IEQ, except for thermal comfort in office rooms. Higher satisfaction levels of perceived air quality, thermal comfort, noise, and lighting, were significantly associated with a reduction in stress at work. Our findings could potentially provide a useful tool for environmental health impact assessment for buildings. 相似文献
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In this paper, a simplified mathematical model develops to study round the year effectiveness of photovoltaic/thermal (PV/T) and earth air heat exchanger (EAHE) integrated with a greenhouse, located at IIT Delhi, India. The solar energy application through photovoltaic system and earth air heat exchanger (EAHE) for heating and cooling of a greenhouse is studied with the help of this simplified mathematical model. Calculations are done for four types of weather conditions (a, b, c and d types) in New Delhi, India. The paper compares greenhouse air temperatures when it is operated with photovoltaic/thermal (PV/T) during daytime coupled with earth air heat exchanger (EAHE) at night, with air temperatures when it is operated exclusively with photovoltaic/thermal system (PV/T) and earth air heat exchanger (EAHE), for 24 h. The results reveal that air temperature inside the greenhouse can be increased by around 7-8 °C during winter season, when the system is operated with photovoltaic (PV/T), coupled with earth air heat exchanger (EAHE) at night. From the results, it is seen that the hourly useful thermal energy generated, during daytime and night, when the system is operated with photovoltaic (PV/T) coupled with earth air heat exchanger (EAHE), is 33 MJ and 24.5 MJ, respectively. The yearly thermal energy generated by the system has been calculated to be 24728.8 kWh, while the net electrical energy savings for the year is 805.9 kWh and the annual thermal exergy energy generated is 1006.2 kWh. 相似文献
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In this paper, an attempt is made to evaluate the exergetic performance of a solar photovoltaic thermal (PV/T) air collector. A detailed energy and exergy analysis is carried out to calculate the thermal and electrical parameters, exergy components and exergy efficiency of a typical PV/T air collector. Some corrections are done on related heat loss coefficients. An improved electrical model is used to estimate the electrical parameters of a PV/T air collector. Further, a modified equation for the exergy efficiency of a PV/T air collector is derived in terms of design and climatic parameters. A computer simulation program is also developed to calculate the thermal and electrical parameters of a PV/T air collector. The results of numerical simulation are in good agreement with the experimental measurements noted in the previous literature. Finally, parametric studies have been carried out. It is observed that the modified exergy efficiency obtained in this paper is in good agreement with the one given by the previous literature. It is also found that the thermal efficiency, electrical efficiency, overall energy efficiency and exergy efficiency of PV/T air collector is about 17.18%, 10.01%, 45% and 10.75% respectively for a sample climatic, operating and design parameters. 相似文献