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Abstract The rational allocation of chiller group plays an important role in the efficient operation of generating units. In this paper, the running characteristics of chiller group under full load are studied. Through the construction of the operation model of the chiller group, the relationship between the start and stop collocation and the operation characteristics of the unit group was explored, and the influence of the unit capacity configuration and the number of table number configuration on the running energy consumption characteristics was studied. The results showed that: the greater the difference of host capacity in the group, the lower the energy consumption under full load. In this example, the difference of energy consumption can reach 8%. At the same time, through the increase in the number of generating units, the difference in host capacity within the group had less impact on energy consumption at full load. For a unit group with the same host capacity, the more the number of units was configured, the lower the operating energy consumption. It provided theoretical support for the selection, collocation and operation management of chillers in practical projects. [ABSTRACT FROM AUTHOR]

Abstract In disaster relief reconstructions, the severe indoor thermal environment of the prefabricated temporary house (PTH) limits its massive utilization. Here, the application of phase change material energy storage system (PESS) has been proposed in the full-scale experimental PTH. In the experimental investigations, a movable PESS was designed aiming at regulating the indoor environment of the PTH during the daytime in hot summer, by charging the cool energy during the nighttime. The movable PESS revealed positive impacts on the indoor environment regulation in the experimental PTH. In addition, the distance between the PESS and the west wall also had influences on the cool energy discharging of the PESS and the indoor thermal environment of the experimental PTH. [ABSTRACT FROM AUTHOR]

Abstract In recent years, underground pipe gallery has become more and more important. Its Special working environment makes temperature monitoring and control increasingly important. paper applies heat-transfer differential equation to the cable to obtain the similarity criterion of cable temperature distribution. After calculating the electric cabin model with different fire separations, it is found that the temperature distribution of the same ampacity in different fire separations conforms to certain rules. The temperature distribution of different ampacity in the same fire separation is also regular: the ampacity rises. 5%, temperature rises by 7%. As a result, the fitting formulas of the current carrying capacity, the length of the fire separation and the location of the highest temperature were also proposed. [ABSTRACT FROM AUTHOR]

Abstract A novel air source heat pump powered bed-based space radiation heating (ASHP-BBSH) system is reported in this paper. This novel system combines the merits from a Chinese Kang, or a heated bed, widely used in northern rural China and a standard ASHP system, which can provide localized space heating via both convection and radiation to maintain a comfortable indoor thermal environment, at reduced energy use. In this novel bed-based system, a bed is heated and thus used as a radiator for providing space heating at both daytime and nighttime. In this paper, firstly, there is an introduction to the novel ASHP-BBSH system. Secondly, based on the experiment setup dimensions, a numerical model is built with a real size thermal manikin. Thirdly, the thermal environment generated by the ASHP-BBSH system is analysed by Fluent. The numerical results show that the ASHP system can achieve a uniform thermal environment and energy saving potential. [ABSTRACT FROM AUTHOR]

Abstract Direct expansion (DX) air conditioning (A/C) system are widely used in various buildings because they are simpler and more energy efficient, and generally cost less to own and maintain. However, it is often problematical for a conventional On-Off controlled DX A/C system to simultaneously control indoor temperature and humidity, since the cooling and dehumidification process of air are highly coupled, unless costly extra equipment or complicated control method to decouple the cooling and dehumidification are provided. Therefore, a novel DX based temperature and humidity independent control air conditioning (DX-THIC) system with two parallel-connected condensers and two electronic expansion valves is presented for improved indoor environmental control and energy efficiency. This paper reports on an experimental study on the operating performances of a prototype experimental DX-THIC system. The experimental results demonstrated that the proposed DX-THIC system can provide independent control of indoor temperature and humidity. The experimental results also demonstrated that the indoor air humidity could influence the operating performances of the DX-THIC system. [ABSTRACT FROM AUTHOR]

Abstract An experiment model is established with the geometrical scale of 5:1 based on an actual utility tunnel engineering, and the air volume is deduced with Re similarity principle. Besides a corresponding numerical simulation model is set up. Through the comparison of the results of experiment and the numerical simulation, the errors are under the allowed error of engineering. The fitted formula between friction resistance and Re may help in the future design and type selection of utility tunnel's ventilation system. [ABSTRACT FROM AUTHOR]

• Optimizing the design and operating of a B-ASHP system is numerically studied. • The operating/design parameters did impact indoor thermal environment. • A surface temperature of around 35 °C was recommended for high energy efficiency. • A higher emissivity was preferred when a lower surface temperature was to be used. Both air source heat pumps (ASHPs) and traditional Chinese-Kangs heating systems are widely used. However, they have their pros and cons. By combining the merits from both an ASHP and a Chinese-Kang heating system, a prototype bed-based ASHP (B-ASHP) system has been proposed, and its operating characteristics experimentally obtained under a fix set of design/operating parameters for the bed-based heating terminal. Therefore, a follow-up numerical study was carried out to numerically evaluate the impacts of optimizing these design/operating parameters, including the location, dimension, surface temperature and surface emissivity of the bed-based heating terminal, on the indoor thermal environment and the operating efficiency of the B-ASHP system. The numerical study results suggested that the variation in these parameters did impact both indoor thermal environment and the operating efficiency of the B-ASHP system, in terms of the uniformity of indoor thermal environment, indoor air velocity distribution and the output heating capacity, as well as the installation space requirement and cost implication. Therefore, care must be exercised in properly balancing all influencing parameters. Also, to both maintain an acceptable indoor thermal environment that can meet the Chinese National Standard, and achieve the best possible operating efficiency of the B-ASHP system, the bed surface temperature of its bed-based heating terminal may be set at around 35 °C. Furthermore, although the changes in surface emissivity did not significantly impact on indoor thermal environment, a higher surface emissivity should be preferred when a lower bed surface temperature was used, so as to further improve potentially the operating efficiency of the B-ASHP system. [ABSTRACT FROM AUTHOR]

• A novel bed-based air source heat pump (B-ASHP) system was proposed. • A prototype experimental B-ASHP system was established and tested. • The B-ASHP system can be operated at both nighttime and daytime modes. • Better thermal comfort and bed surface temperature distribution can be achieved. • A number of issues requiring further considerations were identified. Air source heat pumps (ASHPs) have been increasingly used for space heating due to their high energy efficiency and installation flexibility. On the other hand, in many rural areas in northern Chinese provinces, Kangs, a kind of traditional heating systems based on burning biofuels, are still being used for space heating in winter. Based on the pros and cons of both ASHPs and Kang-based heating systems, a novel bed-based ASHP (B-ASHP) system has been proposed to combine the advantages from both an ASHP and a Kang heating system. In this paper, a prototype experimental B-ASHP system was designed and established, and its dynamic and steady-state operating performances tested in four test cases. The test results from the four test cases demonstrated that the prototype experimental B-ASHP system can achieve quicker increases in indoor air temperatures and bed-surface temperatures than Kang-based heating systems. The use of experimental B-ASHP system can lead to a more uniformed vertical indoor air temperature gradient, thus a better occupants' thermal comfort, than the use of a conventional convection-based ASHP system. Furthermore, compared to using a Kang-based heating system, a more uniformed bed surface temperature may be obtained when using a B-ASHP system. Nonetheless, although currently the prototype experimental B-ASHP system can be satisfactorily operated, a number of issues related to the designs of a B-ASHP system such as choices of refrigerant, refrigerant tube layout optimizations, and the use of variable speed compressors for capacity control, should be carefully considered to further improve its operational safety and energy efficiency. [ABSTRACT FROM AUTHOR]

Hickory is an abundant source of phenolic compounds that exhibit a diverse range of bioactivities. In this study, phenolic compounds were extracted and purified from hickory green husk (HG), hickory nutshell (HN), and hickory seed coat (HS) using solid-phase extraction and ultrasonication (SPE-US). The effects of the SPE-US treatment on the structure and properties of the phenolic compounds were then investigated, including their composition, antioxidant activity, and antimicrobial activity. The dominant phenolic substances in the different extracts after SPE-US treatment were: ellagic acid and trans ferulic acid (HS); ellagic acid and sinapic acid (HN); and rutin (HG). The HS-SPE-US 1 extract exhibited the highest total polyphenol content (416 ± 11 mg GAE/g DW), total flavonoid content (47.51 ± 0.68 mg RE/g DW), Fe3+ reduction ability (74.2 ± 1.0 mmol Fe2+/g DW), radical (DPPH and ABTS) scavenging ability, and antimicrobial activity against Staphylococcus aureus. [Display omitted] • The hickory phenolic compounds were purified by solid phase extraction-sonication. • The purified phenolic compounds were mainly ellagic acid and rutin. • The highest antibacterial activity was contained in seed coat extract. [ABSTRACT FROM AUTHOR]