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R Z Wang - One of the best experts on this subject based on the ideXlab platform.

  • Design and experimental study of a silica gel-water adsorption chiller with modular adsorbers
    International Journal of Refrigeration, 2016
    Co-Authors: Q. W. Pan, L W Wang, R Z Wang, D. Liu
    Abstract:

    A silica gel-water adsorption chiller driven by low-grade heat is developed. System configuration without any vacuum valves includes two sorption chambers, a 4-valve hot/Cooling water coupled circuit and a 4-valve chilled water circuit. Each sorption chamber is composed of one adsorber, one condenser and one evaporator. The design of this chiller, especially the design of modular adsorber, is suitable for low-cost industrial production. Efficient and reliable heat and mass recovery processes are also adopted. This chiller is tested under different conditions and it features the periodic variations of temperatures and Cooling Power. Through the experimental study, the optimal Cooling time, mass recovery time and heat recovery time are 720 s, 40 s and 24 s, respectively. Besides, the obtained Cooling Power, COP and SCP are 42.8 kW, 0.51 and 125.0 W kg-1, respectively, under typical conditions of 86/30/11 °C hot water inlet/Cooling water inlet/chilled water outlet temperatures, respectively.

  • experimental evaluation of a variable effect libr water absorption chiller designed for high efficient solar Cooling system
    International Journal of Refrigeration-revue Internationale Du Froid, 2015
    Co-Authors: R Z Wang, H B Wang
    Abstract:

    Abstract A variable effect LiBr–water absorption chiller is studied in this paper based on a real developed 50 kW prototype. The chiller is designed specifically for the high-efficient utilization of the solar Power with variable temperature. It can obtain the optimized COP and Cooling Power under different heat source temperatures. The construction, circulation and testing system of the chiller were introduced. A typical running condition of the chiller from the starting to the steady operating was given to show the dynamic performance. Several groups of the temperatures and COPs were given to show the steady state performance. These data showed that the COP increased from 0.69 to 1.08 under generation temperature from 95 °C to 120 °C. Besides, the effects of chilled water temperature, Cooling water temperature, pump frequency and opening of valve on COP and Cooling Power were analyzed respectively.

  • performance improvement of an adsorption chiller using composite adsorbent silica gel impregnated with lithium chloride paired with methanol as the adsorbate
    International Journal of Air-conditioning and Refrigeration, 2014
    Co-Authors: Fred T Ishugah, R Z Wang, Liwei Wang, Z S Lu
    Abstract:

    This study aimed at analyzing different operation strategies to improve the performance of a new type adsorption chiller employing a novel composite adsorbent, silica gel impregnated with lithium chloride, paired with methanol as the adsorbate. The chiller's experimental test results showed an average Specific Cooling Power (SCP) and Coefficient of Performance (COP) of 286 W/kg and 0.48, respectively. This was when the average hot water inlet temperature, Cooling water inlet temperature, and chilled water inlet temperature were 83°C, 26°C and 15°C, respectively. In addition, the corresponding mass flow rates were 0.22, 0.39 and 0.09 kg/s, respectively. Despite the fact that the average SCP and COP, were rather satisfactory, analysis of experimental results conducted with different cycle times, inlet hot water temperatures, and hot water flow rates showed that a much better performance could be achieved. Experimental results indicated the following: (1) the COP increased while the SCP decreased with increased cycle time, (2) both the COP and the SCP increased with increase in heat and mass recovery time to an optimal time then started to decrease as heat and mass recovery time increased beyond the optimal time, (3) both the Cooling Power and COP generally increased with increase in inlet hot water temperature at a relatively higher value from 60°C to about 90°C beyond which the incremental value started diminishing, and, (4) increase in mass flow rates produced higher Cooling Power with decreased COP while decrease in mass flow rates of hot water produced lower Cooling Power with increased COP. This paper therefore recommends an adsorption/desorption time, heat and mass recovery time, inlet hot water temperature, and hot water mass flow rate of 780 s, 60 s, 83°C, and 0.22 kg/s as appropriate to give the best chiller performance for refrigeration.

  • novel self cooled solid desiccant Cooling system with integrated desiccant coated heat exchanger and regenerative evaporative cooler
    International sorption heat pump conference (ISHPC2014) College Park United States March 31-April 2 2014., 2014
    Co-Authors: R Z Wang, Y.j. Dai
    Abstract:

    Solid desiccant Cooling technology has become a research focus for its features of energy-saving and eco-friendly. However, widely adopted rotary desiccant wheel Cooling system can’t realize inner-Cooling dehumidification process. In this paper, a novel self-cooled solid desiccant Cooling system (SCDHE) is developed by integrating desiccant coated heat exchanger and regenerative evaporative cooler. In the system, regenerative evaporative cooler is adopted to produce chilled water, which is again pumped into desiccant coated heat exchanger in dehumidification process to realize self-cooled dehumidification process. Similarly, in regeneration process, hot water heated by low grade thermal energy is adopted to regenerate the coated desiccant material. A mathematical model is established to validate the feasibility and to analyze performance of this novel system. Also, effects of ambient air condition are predicted. It is found that SCDHE system is feasible, it can provide satisfied supply air to conditioned room under simulated ARI summer condition, and the required regeneration temperature is from 50-80oC which is lower than rotary wheel desiccant Cooling system. Also, there exists an optimal switch time and suitable control mode for system to obtain enhanced performance in terms of Cooling Power. Compared with conventional DCHE Cooling system without regenerative evaporative Cooling, SCDHE system can provide satisfied supply air while conventional system cannot, also it can obtained increased Cooling Power. Under simulation condition, Cooling Power of SCDHE system increases by about 30% compared with conventional DCHE Cooling system.

  • development and comparison of two bed silica gel water adsorption chillers driven by low grade heat source
    International Journal of Thermal Sciences, 2009
    Co-Authors: Z Z Xia, R Z Wang, Dandong Wang, Yuyang Liu, Congying Chen
    Abstract:

    Abstract A novel silica gel–water adsorption chiller (driven by hot water of 60–90 °C) with three vacuum chambers has been built in Shanghai Jiao Tong University (SJTU). This chiller was an improvement of an earlier deigned chiller and it integrated two single-bed systems (basic system) with only one vacuum valve. The performance of the chiller was tested and compared with the former adsorption chiller. The results show that the Cooling Power and COP of the chiller are 8.70 kW and 0.39 for the heat source temperature of 82.5 °C, Cooling water temperature of 30.4 °C and chilled water outlet temperature of 12 °C. For a higher chilled water outlet temperature of about 16 °C, the COP increases to 0.43 while the Cooling Power is about 11.0 kW. Compared with that of the former chiller, the COP of this chiller increases by 20%.

Weidong Shen - One of the best experts on this subject based on the ideXlab platform.

  • effective angle independent radiative cooler based on one dimensional photonic crystal
    Optical Interference Coatings Conference (OIC) 2019 (2019) paper MC.4, 2019
    Co-Authors: Huaxin Yuan, Chenying Yang, Weidong Shen, Yueguang Zhang
    Abstract:

    We proposed an effective radiative cooler based on one-dimensional photonic crystal, which has an average emissivity of 96% within the atmospheric transparency window (8-13μm) and the maximum Cooling Power density of 113.0W/m2 at night.

  • effective angle independent radiative cooler based on one dimensional photonic crystal
    Optics Express, 2018
    Co-Authors: Huaxin Yuan, Chenying Yang, Xiaowen Zheng, Wen Mu, Wenjia Yuan, Yueguang Zhang, Chaonan Chen, Zhen Wang, Weidong Shen
    Abstract:

    A simple and low-cost radiative cooler based on one-dimensional photonic crystal is proposed in this work, which has an average emissivity of 96% within the atmospheric transparency window (8-13μm). The ultra-broadband emissivity property is realized by constructing the strongly overlapped optical resonances with a tandem structure composed of two lossy materials while an additional lossless material is adopted as the top layer to reduce the Fresnel reflection of the whole structure. The maximum Cooling Power density of the fabricated radiative cooler can reach 113.0W/m2 at night. When integrated with an excellent solar reflector that can reflect 97% incident solar Power, it theoretically has the maximum Cooling Power of 83.0 W/m2 in the case of solar irradiance up to 1000 W/m2 at noon.

Huaxin Yuan - One of the best experts on this subject based on the ideXlab platform.

  • effective angle independent radiative cooler based on one dimensional photonic crystal
    Optical Interference Coatings Conference (OIC) 2019 (2019) paper MC.4, 2019
    Co-Authors: Huaxin Yuan, Chenying Yang, Weidong Shen, Yueguang Zhang
    Abstract:

    We proposed an effective radiative cooler based on one-dimensional photonic crystal, which has an average emissivity of 96% within the atmospheric transparency window (8-13μm) and the maximum Cooling Power density of 113.0W/m2 at night.

  • effective angle independent radiative cooler based on one dimensional photonic crystal
    Optics Express, 2018
    Co-Authors: Huaxin Yuan, Chenying Yang, Xiaowen Zheng, Wen Mu, Wenjia Yuan, Yueguang Zhang, Chaonan Chen, Zhen Wang, Weidong Shen
    Abstract:

    A simple and low-cost radiative cooler based on one-dimensional photonic crystal is proposed in this work, which has an average emissivity of 96% within the atmospheric transparency window (8-13μm). The ultra-broadband emissivity property is realized by constructing the strongly overlapped optical resonances with a tandem structure composed of two lossy materials while an additional lossless material is adopted as the top layer to reduce the Fresnel reflection of the whole structure. The maximum Cooling Power density of the fabricated radiative cooler can reach 113.0W/m2 at night. When integrated with an excellent solar reflector that can reflect 97% incident solar Power, it theoretically has the maximum Cooling Power of 83.0 W/m2 in the case of solar irradiance up to 1000 W/m2 at noon.

Cheng Chou Shieh - One of the best experts on this subject based on the ideXlab platform.

  • design and performance of a solar Powered heating and Cooling system using silica gel water adsorption chiller
    Applied Thermal Engineering, 2009
    Co-Authors: W.s. Chang, C.-c. Wang, Cheng Chou Shieh
    Abstract:

    Abstract In this paper, a solar-Powered compound system for heating and Cooling was designed and constructed in a golf course in Taiwan. An integrated, two-bed, closed-type adsorption chiller was developed in the Industrial Technology Research Institute in Taiwan. Plate fin and tube heat exchangers were adopted as an adsorber and evaporator/condenser. Some test runs have been conducted in the laboratory. Under the test conditions of 80 °C hot water, 30 °C Cooling water, and 14 °C chilled water inlet temperatures, a Cooling Power of 9 kW and a COP (coefficient of performance for Cooling) of 0.37 can be achieved. It has provided a SCP (specific Cooling Power) of about 72 W/(kg adsorbent). Some field tests have been performed from July to October 2006 for providing air-conditioning and hot water. The efficiency of the collector field lies in 18.5–32.4%, with an average value of 27.3%. The daily average COP of the adsorption chiller lies in 33.8–49.7%, with an average COP of 40.3% and an average Cooling Power of 7.79 kW. A typical daily operation shows that the efficiency of the solar heating system, the adsorption Cooling and the entirely solar Cooling system is 28.4%, 45.2%, and 12.8%, respectively.

  • experimental study of a solid adsorption Cooling system using flat tube heat exchangers as adsorption bed
    Applied Thermal Engineering, 2007
    Co-Authors: W.s. Chang, C.-c. Wang, Cheng Chou Shieh
    Abstract:

    In this paper, a solid adsorption Cooling system with silica gel as the adsorbent and water as the adsorbate was experimentally studied. To reduce the manufacturing costs and simplify the construction of the adsorption chiller, a vacuum tank was designed to contain the adsorption bed and evaporator/condenser. Flat-tube type heat exchangers were used for adsorption beds in order to increase the heat transfer area and improve the heat transfer ability between the adsorbent and heat exchanger fins. Under the standard test conditions of 80 °C hot water, 30 °C Cooling water, and 14 °C chilled water inlet temperatures, a Cooling Power of 4.3 kW and a coefficient of performance (COP) for Cooling of 0.45 can be achieved. It has provided a specific Cooling Power (SCP) of about 176 W/(kg adsorbent). With lower hot water flow rates, a higher COP of 0.53 can be achieved.

Yueguang Zhang - One of the best experts on this subject based on the ideXlab platform.

  • effective angle independent radiative cooler based on one dimensional photonic crystal
    Optical Interference Coatings Conference (OIC) 2019 (2019) paper MC.4, 2019
    Co-Authors: Huaxin Yuan, Chenying Yang, Weidong Shen, Yueguang Zhang
    Abstract:

    We proposed an effective radiative cooler based on one-dimensional photonic crystal, which has an average emissivity of 96% within the atmospheric transparency window (8-13μm) and the maximum Cooling Power density of 113.0W/m2 at night.

  • effective angle independent radiative cooler based on one dimensional photonic crystal
    Optics Express, 2018
    Co-Authors: Huaxin Yuan, Chenying Yang, Xiaowen Zheng, Wen Mu, Wenjia Yuan, Yueguang Zhang, Chaonan Chen, Zhen Wang, Weidong Shen
    Abstract:

    A simple and low-cost radiative cooler based on one-dimensional photonic crystal is proposed in this work, which has an average emissivity of 96% within the atmospheric transparency window (8-13μm). The ultra-broadband emissivity property is realized by constructing the strongly overlapped optical resonances with a tandem structure composed of two lossy materials while an additional lossless material is adopted as the top layer to reduce the Fresnel reflection of the whole structure. The maximum Cooling Power density of the fabricated radiative cooler can reach 113.0W/m2 at night. When integrated with an excellent solar reflector that can reflect 97% incident solar Power, it theoretically has the maximum Cooling Power of 83.0 W/m2 in the case of solar irradiance up to 1000 W/m2 at noon.