The investigation of non-Fourier thermal shock fracture behavior in multicrack auxetic honeycomb structures(HSs) is presented. By employing a non-Fourier heat conduction model, the corresponding temperature and therma...
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The investigation of non-Fourier thermal shock fracture behavior in multicrack auxetic honeycomb structures(HSs) is presented. By employing a non-Fourier heat conduction model, the corresponding temperature and thermal stress fields are established. Subsequently, a thermal stress intensity factor(TSIF) model for the auxetic HSs,accounting for multi-crack interactions, is developed. Finally, using the fracture-based failure criterion, the non-Fourier multi-crack critical temperature of the auxetic HSs is determined. This investigation thoroughly examines the effects of the non-Fourier effect(NFE), auxetic property, crack spacing, and crack location on the thermal shock fracture behavior of the auxetic HSs. Results indicate that a stronger NFE leads to weaker thermal shock resistance in auxetic HSs. Regardless of the presence of the NFE, the auxetic property consistently increases the multi-crack critical temperature of the ***, the interaction of multi-crack inhibits thermal shock crack propagation in HSs.
Balcony board embedded in the building exterior wall is a kind of thermal bridges, which increases building energy consumption. In this paper, the balcony structure was determined by referring to the relevant standard...
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In hot-humid climates, the temperature control in transformer and distribution (TAD) rooms is primarily achieved through mechanical vapor compression systems (MVC), which consume significant energy. Conventional evapo...
In hot-humid climates, the temperature control in transformer and distribution (TAD) rooms is primarily achieved through mechanical vapor compression systems (MVC), which consume significant energy. Conventional evaporative condenser system (MVC-DEC) can improve the energy efficiency of air conditioning, but the effect is limited in hot-humid climate. This study proposes a split-type dual-precooling hybrid system (MVC-IEC), which combines indirect evaporative cooling (IEC) to precool both evaporator and condenser, aiming to improve the energy efficiency of TAD room air conditioning system in hot-humid climates. Firstly, a distributed-parameter model of MVC, MVC-DEC and MVC-IEC was established and experimentally validated. Subsequently, the effects of several key parameters (indoor set temperature and load, ambient temperature and humidity, air flowrate and the number of heat/mass transfer units of IEC) were investigated. Finally, a prediction load model was established for TAD room to comprehensively evaluate the seasonal energy-saving potential of each system in hot-humid climates. The results show that MVC-IEC has the best energy saving effect under most conditions of high temperature, humidity and indoor heat load. Compared with MVC and MVC-DEC, MVC-IEC improves the COP by 37.5 and 35.6 at most, respectively. In four typical hot-humid cities in China during summer, the seasonal COP and energy saving rate of MVC-IEC reached by 18.9–30.2 and 65.9–74.5 %, respectively, while the those of MVC-DEC are only 6.4–7.0 and 5.9–8.9 %. Furthermore, MVC-IEC has satisfactory economic and environmental performance: it reduces the refrigerant-cycle cooling capacity by approximately one-third, cuts carbon emissions by 2.8–3.0 ton/year, and achieves an equipment payback period of 3.1–3.3 years.
Mould is an important factor which affects building environment and indoor air quality. Firstly, a variety of damages of mould contamination to human and building are reviewed. Then, the crucial factors of mould growt...
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Mould is an important factor which affects building environment and indoor air quality. Firstly, a variety of damages of mould contamination to human and building are reviewed. Then, the crucial factors of mould growth are analyzed;temperature and humidity are key factors. After that, the indoor mould growth models were analyzed. Heat and moisture transfer in building envelope is a key factor which affects mould growth environment;wall is sensitive to reach the critical condition which leads to mould growth and reproduction, results in contamination.
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