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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]