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1、8000 英文單詞, 英文單詞,4.1 萬(wàn)英文字符,中文 萬(wàn)英文字符,中文 12400 字文獻(xiàn)出處: 文獻(xiàn)出處:Jamar A, Majid Z A A, Azmi W H, et al. A review of water heating system for solar energy applications[J]. International Communications in Heat and Mass Transfer, 20

2、16, 76: 178-187.A review of water heating system for solar energy applicationsA.Jamar, Z.A.A. Majid, W.H. Azmi, M. Norhafana, A.A. RazakAbstractSolar energy is one of the widely used renewable energy that can be harnesse

3、d either by directly deriving energy from sunlight or indirectly. Solar water heating system, on the other hand, is one of the applications of solar energy that has drawn great attention among researchers in this field.

4、Solar collectors, storage tanks and heat transfer fluids are the three core components in solar water heater applications, which are reviewed in this paper. This paper discusses the latest developments and advancement of

5、 a solar water heater based on the three basic components that may affect the thermal performance of the system. It also reviews the development of various types of solar collectors in solar water heater, including both

6、the non-concentrating collectors (flat plate collector, evacuated tube collector) and the concentrating collectors (parabolic dish reflector, parabolic trough collector). All these are studied in terms of optical optimiz

7、ation, heat loss reduction, heat recuperation enhancement and different sun tracking mechanisms. Among the non-concentrating and concentrating collectors, the parabolic dish reflector collectors show the best overall per

8、formance. The use of nanofluids as a heat transfer fluid was also discovered in this paper.Keywords: Solar energy, Solar water heating system, Solar water heater, Renewable energy1. IntroductionToday, fossil fuel has bee

9、n primarily used to heat and power homes and fuel cars [1]. It is convenient to use coal, oil and natural gas for meeting human's energy needs [2], but the limited supply of these fuels has become the main constraint

10、 for people to persist them as the continuous sources on Earth [3,4]. In recent years, high advancement in Malaysia's economy has steered to a vividly increases in energy consumption, particularly electrical energy u

11、sed in commercial and domestically building [5]. As energy plays a crucial role in the daily needs of humans [6], there are many alternative energy sources that can be used instead of fossil fuels [7,8], and one of them

12、is renewable energy (RE) [9]. RE can be described as energy that can be generated by natural sources such as sunlight; which is a primary source of energy [10]. The major gains of RE is that no fuel is necessarily requir

13、ed, which eradicates the emission of carbon dioxide (CO2); one of the factors in air pollution. Insufficient fossil fuel supplies and disproportionate gas emissions resulting from increasing fossil fuel consumption have

14、become the worst contribution to the current global energy problem. It was recounted that the present petroleum consumption was 105 times faster than the amount nature can create [11]. Predictably, at this huge rate of c

15、onsumption, the world's fossil fuel reserves will diminish by 2050 [11,12] and the global demand for energy would turn to be approximately 30 and 46 TW by 2050 and 2100, respectively [13]. Even though the fossil fuel

16、s supply more than 90% of energy demand, they indeed convey a vertical figure in environmental cost [14].In China, the application of RE in buildings is a promising solution toward the conflict between the growing energy

17、 demand and environ- mental protection [15]. It could also provide a technology is usually not an issue for the user as it is a “behind-the-screen” technology [35]. Moreover, simplicity, technological feasibility, and ec

18、onomical and commercial viability are the strengthening factors of solar water heaters which made them popular among the RE products all over the world [36,37]. For instance, the most popular categories of hot water heat

19、ers in the China market are electric water heaters, gas water heaters, and solar water heaters [38].In addition to the system, a collector functions to collect solar energy from sunlight whereas a storage tank stores hot

20、 water that has been produced through the system itself. In making sure that the water is always hot, the tank must be insulated well to avoid heat losses, as mentioned earlier [39]. Solar energy can be acquired when the

21、 absorber panel coated with selected coating transfers the heat to the riser pipes underneath the panel. The water will pass through the riser to be heated up and then channeled to the storage tank. The recirculation of

22、the same water through the absorber panel in the collector raises the temperature up to 80 °C (maximum) on a good sunny day. This is recognized as a complete system of hot water using solar energy with the use of eq

23、uipment such as a solar collector, a storage tank and pipelines and is known as the solar water heating system. The existing solar water heater today consists of a cylindrical glass tube that works as the receiver of sol

24、ar energy and a copper coil through which the water flows, that is placed inside the glass tube and acts as the collector [40]. The technical and environmental performance of a solar water heater is examined using the me

25、thod of life cycle assessment (LCA) [41,42].Nevertheless, there is still much to do to improve the performance of solar water heaters which include improving the thermal stratification of the storage tank, enhancing the

26、performance of the collector, boosting the heat transfer techniques (consist of collector designs, collector tilt angles, coating of pipes, fluid flow rates, thermal insulation, integrated collector storage, thermal ener

27、gy storage, use of phase change materials (PCM) [43], and insertion of twisted tapes) [44], and optimizing the controller. Besides, optimizing the hot water tank structure and enhancing the immersed heat exchange perform

28、ance is also considered as one of their best ways [45].3. Solar water heating systemOne of the most widely known solar thermal applications is the solar water heating system [46]. The solar water heating system uses natu

29、ral solar thermal technology [47,48] which is where solar radiation is converted into heat and transmitted into a transfer medium such as water, water antifreeze or air. This system is often feasible for replacement of e

30、lectricity and fossil fuels used for water heating [49]. Generally, the system is very simple because it requires only sunlight to heat the water. It works when the working fluid is brought in contact with a dark surface

31、 (high absorptive) that is exposed to sunlight, which then causes the temperature of the fluid to rise [3]. This fluid may be caused by the water being heated directly, which is called a direct system, or it may be a hea

32、t transfer fluid (such as a glycol or water mixture) that is passed through some form of a heat exchanger and called an indirect system. These systems can be classified into two main categories; active system and passive

33、 system [50] as shown in Fig. 1. The active system can be divided into two which are the open loop and close loop system whereas the passive system uses the system of thermosiphon and integral collector storage (ICS).Alm

34、ost all solar water heating systems used in temperate climates are active systems that make use of pumps to circulate the heat transfer fluids [24]. Theoretically, these systems commonly use flat plates or evacuated tube

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