Key Engineering Materials Vol. 517

Abstract: The purpose of this study is to discuss the use of energy in hotel building in Hunan province, P. R. China, and to explore the application of building energy conservation. 25 hotel buildings were selected and the investigations of energy consumption data was carried through in Changsha of Hunan province .The building comprehensive consumption of energy and electricity were got from the energy consumption computing method of public buildings. It can be got these indexes of unit energy consumption electricity consumption and so on through unit conversion. According to the current situation of building energy consumption and the related standings of Changsha, such buildings whose norm index range of energy and electricity can be obtained. Conclusion are as follows: It provide guiding significance for the energy-saving prediction which entire building and all of its system .This paper also provides some useful measures which about the applied promotion of related energy-saving technology in such buildings of the region.

Abstract: Fiber-reinforced polymer (FRP) bars are emerging as a competitive option for replacing steel bars as reinforcement in various concrete structures exposed to aggressive environments. However, the low elastic modulus and brittleness of FRP bars significantly reduce the stiffness and the ductility of FRP-reinforced concrete (FRP-RC) members. In order to improve the flexural behavior of FRP-RC members and meanwhile ensure their satisfactory corrosion-resistant performance, an innovative FRP-reinforced concrete encased steel composite (FRP-RCS) member, which consists of ductile structural steel shapes in combination with corrosion-resistant FRP-reinforced concrete, was conceived and studied. An experimental investigation on the flexural behavior of the proposed FRP-RCS beams was conducted by testing a total of five large-scale simply supported beam specimens subjected to four-point bending loads. The test specimens included one FRP-RC beam reinforced with GFRP bars only and four FRP-RCS beams reinforced with both GFRP bars and encased structural steel shapes. The main parameters considered in this study were concrete compressive strength and amounts of GFRP reinforcement. The test results indicated that using encased steel shapes provided a significant enhancement in load carrying capacity, stiffness, ductility and energy absorption capacity of test beams. The tested FRP-RC beam suffered a brittle failure caused by sudden fracture of tensile GFRP bars whereas the proposed FRP-RCS beams behaved in a ductile manner due to the beneficial residual strength of encased steel shapes following concrete crushing. In addition, the experimental results also demonstrated that the concrete compressive strength had little effect on load carrying capacity of FRP-RCS beams whereas the load carrying capacity can be enhanced by increasing the reinforcement ratio. Analytical methods were also constructed using OpenSEES2.2.2 to simulate the load-deflection response of tested beams..

Abstract: Using an appropriate evaluation index for energy consumption is advantageous for evaluating energy saving effect of buildings correctly and carrying out energy-saving action reasonably. As a result, it is important to establish a practical quota of energy consumption for promoting energy-saving emission reduction. Energy consumption for residential buildings has been influenced by the behavior of residents in the building largely, and has a higher uncertainty, so it brings great difficulty to researches. Considering the characteristics of residential buildings, this paper uses comprehensive energy consumption per unit as evaluation index. Based on the investigation results and related studies, the residential buildings in Changsha are analyzed with statistical methods, in order to know more about the energy consumption level and structure for the residential buildings in Changsha. This paper shows the characteristics of the energy consumption of the residential buildings in Changsha, and work out the range of the comprehensive energy consumption per unit. The result provides a reference to make out energy policy and enhance the management of energysaving. It can be also used to guide the residents have a reasonable electric power utilization.

Abstract: This paper introduces the operating principle and system components of Ceiling Radiant Cooling Panels (CRCP) with Dedicated Outdoor Air Systems (DOAS), moreover, analyses not only the advantages of CRCP/DOAS system in terms of comfort, energy conservation and healthy environmental protection, but also the three obstacles to the system when running in summer moist heat regions condensation, radiant cooling capacity and first cost. The major defect of CRCP is proposed that the surface temperature of the panel is uneven, while the shortage of DOAS is the insufficiency of outdoor air handling. A new CRCP/DOAS system is provided in this paper, including patent radiant cooling panel and patent air condition. We also expound the characteristics of this new system, and list the recommended design parameters as well.

Abstract: Environmentally sustainable building construction has experienced significant growth during the past 10 years. The public is becoming more aware of the benefits of green construction, and green building is leading to changes in the way of owners, designers, contractors, and approach of the design, construction. Concrete-filled square steel tubular special shaped columns - steel beams residence installing efficient and light heat insulation wall is welcome for both owners and designers because of the columns having the same thickness with limb-filled walls, no-shocked indoor, easy to decoration and furniture layout, increasing in the actual using areas and saving carbon. The composite frame fully develops the merits of steel and concrete, and thus is reasonable and economical from both structural and construction viewpoints. The connection region as main force transfer component is key to the research of frame. Compared with the joint of ordinary reinforced concrete special shaped frame, the joint between concrete-filled square steel tubular special-shaped columns and steel beams has the advantage of better ductility , higher loading capacity, uncomplicated reinforcement disposing and convenient in construction. This paper discusses the features of concrete-filled square steel tubular special shaped columns - steel beams frame, and the design and use of beam-column joint. From the experimental study on seismic behavior of the joint, it is shown that the joint has strong energy dissipation capacity and higher loading capacity. So it is expected it could play an important role in residence structures. This study is helpful for further study of the design and use of the joint between concrete-filled square steel tubular special-shaped columns and steel beams.

Abstract: Compound condensing heat pump combines the advantages of heat pump technology and condensing heat recovery technology. It takes full account of the common infrastructure in the cooling and heat source system and greatly increases equipment utilization ratio. It also recycles condensing heat to produce sanitary hot water efficiently while ensuring cooling and heating of heat pump to achieve the same effect. The distinctive technical features of the compound condensation / evaporation of four functional heat pump ensure its efficient and reliable operation. This heat pump system runs in several models throughout the year,which include the refrigeration mode, refrigeration&domestic hot water mode, domestic hot water mode and heating mode. The performance in refrigeration mode and refrigeration&domestic hot water mode is studied by a designed experiment is done and the an explicit analysis is made. By comparing the results of simlation and experiment,an agreement can be shown clearly. Therefore,the final conclusion is drawn:the performance of compound condensation / evaporation of four functional heat pump is improved over the traditional heat pump.It is worthy to further promote for the sake of energy saving.

Abstract: A technique for increasing the flexural behavior of stone beams using near-surface mounted (NSM) carbon fiber reinforced polymer (CFRP) rods is proposed. Four granite beams were tested under monotonic loading to investigate the effectiveness of this technique. One conventional stone beam was kept unreinforced as the control specimen and three beams were reinforced with NSM CFRP rods. The main test parameters included rod diameters and reinforcement ratios. Three types of failure modes were observed during testing, namely, abrupt fracture for conventional stone beams, flexure failure for moderately-reinforced beams and flexure-shear failure for over-reinforced beams, respectively. Test results showed that reinforcing with NSM CFRP could significantly enhance the flexural behavior of stone beams. For specimens with a reinforcement ratio of 0.14%, an average increase up to 91.0% in the ultimate load with respect to that of the control beam was obtained and the deformation capacity was dramatically increased. For specimens with a reinforcement ratio of 0.28%, though flexural behavior was greatly enhanced, an unfavorable shear failure was observed.

Abstract: In order to evaluate the energy-saving effect of the bamboo plywood as building enclosure, by measuring thermal conductivity of compound bamboo building enclosure with different moisture content, performance function between bamboo characteristic and thermal conductivity were deduced with numerical analysis method. First, we measured thermal conductivity with different moisture content. For the accuracy of data, we put a thin plastic film between the heating layer of the tester and the bamboo plywood to reduce water evaporation. Then we got the functional relation of moisture content and thermal conductivity, by using numerical analysis software. Finally, according to the national related standard and the performance of the bamboo plywood within different moisture content, we analyzed the advantages and disadvantages of the bamboo plywood as building enclosure. The results showed that the heat preservation and thermal insulation properties of bamboo plywood as construction materials are both stronger than traditional building materials such as reinforced concrete with different moisture content. Meanwhile, so as to ensure the heat preservation and thermal insulation properties and to achieve a good energy saving effect, wed better keep the moisture content of bamboo plywood in a low state.

Abstract: In the newly decorated office premises, the architectural decoration material will release much polluted gas, thus the IAQ is highly concerned. Natural ventilation through open windows can influence the IAQ. To study the effects of opening windows on the indoor air quality of newly decorated office premises, we choose several newly decorated offices in a commercial building in Changsha, a city in hot summer and cold winter region of China, as the study object. The 4 contrastive research schemes in the winter are adopted to acquire the results. Field-testing and air sampling methods were taken respectively to the 4 schemes to measure the concentrations of the main pollution composition such as formaldehyde, ammonia, benzene and TVOC in the offices. Meanwhile, relevant questionnaire surveys towards the four schemes were taken to the staff in the offices. We have synthesized and analyzed the IAQ condition of the 4 research schemes from the results of the tests and surveys. The result of the study shows that: the IAQ is the worst and cannot come up to the national standard when closing windows all day long in the newly decorated offices. Also some staff have a series of adverse reactions working in the work environment for a long time. All the other three schemes can improve the IAQ differently, and the scheme that opening windows all day long can improve the IAQ the best. Meanwhile, people can feel the change of IAQ effected by the 3 ventilation schemes if he/she is working for a long time in the offices.

Abstract: The cavity heat insulation walls as a major form of multiple thermal insulation walls is the development of the energy-efficiency building materials. Attention is taken to describe the mechanics properties of cavity walls under out-of-plane load. In this paper, Mechanical model is developed for masonry walls out-of-plane loaded, and the analytical expressions about the internal force and deflection are abtained using the orthotropic theory. Limit deflection of interior walls under vertical and horizontal loads is calculated by mathematical software (MATLAB) and is simulated based on finite element analysis software (ANSYS) respectively. Finally, the results indicate that vertical loads and elastic modulus have great impact on the maximum deflection of masonry walls. Numerical computations show that the shell element of SHELL63 is well used in analysis of the internal force and deflection of masonry walls out-of-plane loaded.