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

  • experimental study of an Adsorption Chiller for extra low temperature waste heat utilization
    Applied Thermal Engineering, 2019
    Co-Authors: Jiajie Peng, R. Z. Wang
    Abstract:

    Abstract Lots of low temperature waste heat exists in industrial fields which also requires cooling processes, i.e.: data center and glass and liquid crystal display panel manufacturing. Silica gel-water Adsorption refrigeration can well match the operation temperature in waste heat utilization for these applications but its technical feasibility and experimental performance is not studied. In this paper, a silica gel-water Adsorption Chiller using mass recovery process is built and experimentally studied under the condition of lower than 80 °C driving hot water temperature. For the case of data center waste heat utilization, the Adsorption Chiller can be well operated under the condition of driving temperatures of 51.4–61.3 °C, with the COPs (coefficient of performance) of 0.285–0.477 and SCPs (specific cooling power) of 71.2–108.4 W∙kg−1 while producing 18.8–22.4 °C chilled water. For the cases of glass and liquid crystal display panel manufacturing waste heat utilization, COPs of 0.317–0.483 and SCPs of 95.2–146.7 W∙kg−1 are obtained under the conditions of driving temperatures of 56.2–74.9 °C and chilled water outlet temperatures of 14.2–16.8 °C. These experimental results indicate that feasibility in operation and good performance of silica gel-water Adsorption Chiller for extra low temperature waste heat utilization is confirmed.

  • study on operation strategy of a silica gel water Adsorption Chiller in solar cooling application
    Solar Energy, 2018
    Co-Authors: R. Z. Wang
    Abstract:

    Abstract Conventional operation strategy of silica gel-water Adsorption Chiller in solar cooling application uses fixed cycle time, but it deviates from real optimal cycle time because of varied solar hot water temperature. Mathematical model and simulation of a solar silica gel-water Adsorption Chiller was done and performance comparison in two operating strategies (fixed and varied cycle time) was made according to experiment data of a real solar system. An estimating equation for the optimal cycle time was developed by the simulation results, considering both COP and SCP by a weighting factor. Correlation of optimal cycle time and hot water temperature was fitted in a linear equation. Optimal half cycle time decreased with increasing hot water temperature and weighting factor. COPs of varied cycle time were much larger than those of fixed cycle time whereas SCPs of varied cycle time and fixed cycle time were nearly the same. So operation strategy of silica gel-water Adsorption Chiller with varied cycle time can significantly improve the whole utilization efficiency of solar cooling system without any decrease in cooling capacity.

  • low temperature grain storage with a solar powered Adsorption Chiller a case study
    International Journal of Green Energy, 2014
    Co-Authors: R. Z. Wang, Jiamin Shen
    Abstract:

    Solar energy refrigeration is very attractive for low-temperature grain storage because the cooling load of low-temperature grain storage is roughly in phase with solar energy availability. In this study, a solar-powered Adsorption Chiller was developed with aim of developing an alternative refrigeration device for low-temperature grain storage. The solar-powered Adsorption Chiller was put into experimental operation during summer and autumn. Test results show that the solar-powered Adsorption Chiller can produce a cooling capacity about 66–90 W per m2 collector area. Its daily solar-cooling COP (coefficient of performance) is about 0.1–0.13 under the climatic conditions of daily solar radiation being about 16–21 MJ/m2·day. With appropriate ventilation appliance, this kind of solar-powered Adsorption Chiller could be considered as an alternative for low-temperature grain storage in most areas of China.

  • experimental study on an Adsorption Chiller employing lithium chloride in silica gel and methanol
    International Journal of Refrigeration-revue Internationale Du Froid, 2012
    Co-Authors: L X Gong, R. Z. Wang, Z S Lu
    Abstract:

    Abstract A novel composite adsorbent – methanol Adsorption Chiller was proposed and manufactured. It was filled by the adsorbent composed by Lithium Chloride and silica gel. Methanol was used as adsorbate and refrigerant. Experiment results showed that compared with silica gel-water Chiller, SCP (specific cooling power) and COP (coefficient of performance) of this novel Chiller were improved by 16.3% and 24.2% separately when the temperatures of hot water inlet, cooling water inlet and chilled water outlet were 85 °C, 30 °C and 15 °C.

  • design and performance prediction of a new generation Adsorption Chiller using composite adsorbent
    Energy Conversion and Management, 2011
    Co-Authors: L X Gong, R. Z. Wang, Congying Chen
    Abstract:

    Abstract This paper presents a novel Adsorption Chiller using composite adsorbent “employing lithium chloride in silica gel” as adsorbent and water as adsorbate. A new type adsorbent bed is used to accommodate the composite adsorbent. The mass recovery between two adsorbent beds usually results in the adsorbate unbalance. So a novel auto water makeup unite is used to solve the problem. A dynamic model of the Adsorption Chiller is built based on the Adsorption isotherms to predict the performance. The simulation result shows that the coefficient of performance (COP) and the cooling capacity will increase by using this new composite adsorbent. When the temperatures of hot water inlet, cooling water inlet, and chilled water inlet are 363, 303 and 293 K, COP will be 0.43, and the cooling capacity will be 5.295 kW. Also operation strategy is optimized. Different temperatures of hot water inlet, cooling water inlet and chilling water inlet will result in different COP and cooling capacity.

Bidyut Baran Saha - One of the best experts on this subject based on the ideXlab platform.

  • solar thermal powered Adsorption Chiller
    2020
    Co-Authors: Mahbubul Muttakin, Bidyut Baran Saha
    Abstract:

    Adsorption based cooling systems are gaining considerable attention since it can utilize low grade thermal energy, which otherwise could go as a waste. Heat sources possessing a temperature of as low as 60 °C can drive an Adsorption Chiller and that temperature requirement is even lower in the case of multi-stage Adsorption cooling systems. A typical flat plate solar collector can provide hot water having a temperature of 65 °C in most of the countries in the Asian region. The temperature of evacuated tube collectors’ water outlet can reach above 95 °C. In order to make use of such collectors, in conjunction with other auxiliary heat sources, for providing heat to power an Adsorption Chiller, it is imperative to have a proper mathematical model. This can aid in designing the network and predicting the performance of the whole system, prior to installation. This chapter focuses on the modelling of a system that incorporates flat plate collectors, evacuated tube collectors and a thermally powered Adsorption Chiller. Here, mathematical equations to calculate the efficiency of flat plate and evacuated tube collectors are presented; processes that are involved in a typical two bed Adsorption cooling system are explained in brief, and a mathematical model of an Adsorption Chiller, that employs mass and heat recovery schemes is developed. Finally, the simulation results of the model are presented, and the performance of the Chiller is investigated to demonstrate a clear understanding of its operation.

  • Dynamic behaviors of Adsorption Chiller: Effects of the silica gel grain size and layers
    Energy, 2014
    Co-Authors: Anutosh Chakraborty, Bidyut Baran Saha, Yu I Aristov
    Abstract:

    This article presents the dynamic behaviour of a single effect two bed Adsorption Chiller employing adsorbent beds with various layers of loose grain configurations and silica gel particle sizes, which is based on the experimentally confirmed Adsorption isotherms and kinetics data. Compared with the experimental data of conventional Adsorption Chiller based on RD silica gel-water pair, we found that the silica gel configuration in terms of layers and sizes provides an interesting result, that is, the "grain size sensitive" regime is realized for large adsorbent grains with more layers. From numerical simulation, it is found that the specific cooling power and the coefficient of performance are reduced and the peak chilled water temperatures are increased with increasing the grain size and grain layers. We also demonstrate here that the sizes and layers of adsorbents should be considered for the design of Adsorption heat exchanger for Adsorption cooling applications.

  • study on a solar heat driven dual mode Adsorption Chiller
    Energy, 2013
    Co-Authors: Khairul Habib, Biplab Choudhury, Pradip Kumar Chatterjee, Bidyut Baran Saha
    Abstract:

    Environmental concerns and the rising energy cost necessitate looking for renewable energy driven environmentally benign Adsorption cooling systems. Solar powered Adsorption Chillers with non-concentrating flat plate or evacuated tube collectors face the problem of not getting adequate driving source temperature during some months of the year. Multi-staging of the Adsorption cycle is then needed to exploit the low driving source temperature. A simulation study of a solar thermal driven dual-mode, four-bed silica gel–water Adsorption Chiller is undertaken in this work. The solar thermal collector data of Durgapur (23.48 °N, 87.32 °E), India has been used as the heat source for the dual-mode Chiller. For a driving source temperature above 60 °C, the Chiller works as a single stage four-bed Adsorption Chiller; while the Chiller functions as a two stage Adsorption Chiller when the driving source temperature falls below 60 °C. With a cooling water temperature of 30 °C, this two stage Chiller has been found to produce cooling effect with a driving source temperature as low as 40 °C. Results indicate that the dual-mode Chiller is capable of providing cooling throughout the year under the climatic condition of Durgapur, India.

  • Study on a solar heat driven dual-mode Adsorption Chiller
    Energy, 2013
    Co-Authors: Khairul Habib, Biplab Choudhury, Pradip Kumar Chatterjee, Bidyut Baran Saha
    Abstract:

    Environmental concerns and the rising energy cost necessitate looking for renewable energy driven environmentally benign Adsorption cooling systems. Solar powered Adsorption Chillers with non-concentrating flat plate or evacuated tube collectors face the problem of not getting adequate driving source temperature during some months of the year. Multi-staging of the Adsorption cycle is then needed to exploit the low driving source temperature. A simulation study of a solar thermal driven dual-mode, four-bed silica gel-water Adsorption Chiller is undertaken in this work. The solar thermal collector data of Durgapur (23.48°N, 87.32°E), India has been used as the heat source for the dual-mode Chiller. For a driving source temperature above 60°C, the Chiller works as a single stage four-bed Adsorption Chiller; while the Chiller functions as a two stage Adsorption Chiller when the driving source temperature falls below 60°C. With a cooling water temperature of 30°C, this two stage Chiller has been found to produce cooling effect with a driving source temperature as low as 40°C. Results indicate that the dual-mode Chiller is capable of providing cooling throughout the year under the climatic condition of Durgapur, India. © 2013 Elsevier Ltd.

  • experimental study on a three bed Adsorption Chiller
    International Journal of Air-conditioning and Refrigeration, 2011
    Co-Authors: M Z I Khan, Bidyut Baran Saha, Shahnaz Sultana, Atsushi Akisawa
    Abstract:

    This article presents the experimental results of a three-bed advanced Adsorption Chiller using silica gel–water as the adsorbent–refrigerant pair. The three-bed Adsorption Chiller comprises three sorption elements (Hexs), one evaporator and one condenser. In the present study, the heat source temperature varies from 55°C to 80°C along with coolant inlet temperature at 30°C and the chilled water inlet temperature at 14°C. Mass recovery process occurs between Hex1 and Hex2 and no mass recovery with Hex3. The performances in terms of cooling capacity (CC) and coefficient of performance (COP) are compared with those of conventional three-bed without mass recovery scheme. Results show that three-bed with mass recovery scheme provides more CC values than those provided by the three-bed system without mass recovery scheme while it provides better COP values for 65–75°C heat source temperature.

Atsushi Akisawa - One of the best experts on this subject based on the ideXlab platform.

  • experimental study on a three bed Adsorption Chiller
    International Journal of Air-conditioning and Refrigeration, 2011
    Co-Authors: M Z I Khan, Bidyut Baran Saha, Shahnaz Sultana, Atsushi Akisawa
    Abstract:

    This article presents the experimental results of a three-bed advanced Adsorption Chiller using silica gel–water as the adsorbent–refrigerant pair. The three-bed Adsorption Chiller comprises three sorption elements (Hexs), one evaporator and one condenser. In the present study, the heat source temperature varies from 55°C to 80°C along with coolant inlet temperature at 30°C and the chilled water inlet temperature at 14°C. Mass recovery process occurs between Hex1 and Hex2 and no mass recovery with Hex3. The performances in terms of cooling capacity (CC) and coefficient of performance (COP) are compared with those of conventional three-bed without mass recovery scheme. Results show that three-bed with mass recovery scheme provides more CC values than those provided by the three-bed system without mass recovery scheme while it provides better COP values for 65–75°C heat source temperature.

  • the performance analysis of a novel dual evaporator type three bed Adsorption Chiller
    International Journal of Refrigeration-revue Internationale Du Froid, 2010
    Co-Authors: Takahiko Miyazaki, Atsushi Akisawa, Bidyut Baran Saha
    Abstract:

    Abstract This paper deals with the performance evaluation of an innovative, waste heat driven dual evaporator type three-bed Adsorption cycle for cooling application. The innovative Adsorption Chiller has two evaporators, three adsorbent beds, and a condenser, and the evaporators work at different pressure levels. The effects of hot water inlet temperature, chilled water inlet and outlet temperatures, and cycle time on the specific cooling capacity (SCC) and coefficient of performance (COP) were predicted by simulation. For the same operating condition, the SCC and COP of the dual evaporator type three-bed Adsorption Chiller were found to be 1.5 and 1.7 times higher than those of the two-bed single-stage Adsorption Chiller, respectively.

  • The performance analysis of a novel dual evaporator type three-bed Adsorption Chiller
    International Journal of Refrigeration, 2010
    Co-Authors: Takahiko Miyazaki, Atsushi Akisawa, Bidyut Baran Saha
    Abstract:

    This paper deals with the performance evaluation of an innovative, waste heat driven dual evaporator type three-bed Adsorption cycle for cooling application. The innovative Adsorption Chiller has two evaporators, three adsorbent beds, and a condenser, and the evaporators work at different pressure levels. The effects of hot water inlet temperature, chilled water inlet and outlet temperatures, and cycle time on the specific cooling capacity (SCC) and coefficient of performance (COP) were predicted by simulation. For the same operating condition, the SCC and COP of the dual evaporator type three-bed Adsorption Chiller were found to be 1.5 and 1.7 times higher than those of the two-bed single-stage Adsorption Chiller, respectively. © 2009 Elsevier Ltd and IIR.

  • performance evaluation of multi stage multi bed Adsorption Chiller employing re heat scheme
    Renewable Energy, 2008
    Co-Authors: M Z I Khan, Bidyut Baran Saha, K C A Alam, Atsushi Akisawa, Takao Kashiwagi
    Abstract:

    This paper deals with the performance investigation of a silica gel/water-based multi-stage, multi-bed, six-bed Adsorption Chiller employing re-heat scheme. The innovative Chiller is powered by waste heat or renewable energy sources of temperature between 50 and 70°C along with a coolant of inlet temperature at 30°C for air-conditioning purpose. The performance of the six-bed Adsorption Chiller using re-heat scheme is compared with that of the six-bed Chiller without re-heat. With the same operating conditions, such as the heat transfer fluid inlet (HTF) temperatures, HTF flow rates, Adsorption/desorption cycle time and same Chiller physical dimension, it is found that both the cooling capacity (CC) and the coefficient of performance (COP) of the three-stage Chiller with re-heat scheme are superior than those of the three-stage Chiller without re-heat scheme.

  • study on a dual mode multi stage multi bed regenerative Adsorption Chiller
    Renewable Energy, 2006
    Co-Authors: Bidyut Baran Saha, Yoshinori Hamamoto, Shigeru Koyama, Kim Choon Ng, Atsushi Akisawa, Takao Kashiwagi
    Abstract:

    In this paper, a detailed parametric study on a dual-mode silica gel–water Adsorption Chiller is performed. This advanced Adsorption Chiller utilizes effectively low-temperature solar or waste heat sources of temperature between 40 and 95°C. Two operation modes are possible for the advanced Chiller. The first operation mode will be to work as a highly efficient conventional Chiller where the driving source temperature is between 60 and 95°C. The second operation mode will be to work as an advanced three-stage Adsorption Chiller where the available driving source temperature is very low (between 40 and 60°C). With this very low driving source temperature in combination with a coolant at 30°C, no other cycle except an advanced Adsorption cycle with staged regeneration will be operational. In this paper, the effect of chilled-water inlet temperature, heat transfer fluid flow rates and Adsorption–desorption cycle time effect on cooling capacity and COP of the dual-mode Chiller is performed. Simulation results show that both cooling capacity and COP values increase with the increase of chilled water inlet temperature with driving source temperature at 50 and 80°C in three-stage mode, and single-stage multi-bed mode, respectively. However, the delivered chilled-water temperature increases with chilled-water inlet temperature in both modes.

Takao Kashiwagi - One of the best experts on this subject based on the ideXlab platform.

  • performance evaluation of multi stage multi bed Adsorption Chiller employing re heat scheme
    Renewable Energy, 2008
    Co-Authors: M Z I Khan, Bidyut Baran Saha, K C A Alam, Atsushi Akisawa, Takao Kashiwagi
    Abstract:

    This paper deals with the performance investigation of a silica gel/water-based multi-stage, multi-bed, six-bed Adsorption Chiller employing re-heat scheme. The innovative Chiller is powered by waste heat or renewable energy sources of temperature between 50 and 70°C along with a coolant of inlet temperature at 30°C for air-conditioning purpose. The performance of the six-bed Adsorption Chiller using re-heat scheme is compared with that of the six-bed Chiller without re-heat. With the same operating conditions, such as the heat transfer fluid inlet (HTF) temperatures, HTF flow rates, Adsorption/desorption cycle time and same Chiller physical dimension, it is found that both the cooling capacity (CC) and the coefficient of performance (COP) of the three-stage Chiller with re-heat scheme are superior than those of the three-stage Chiller without re-heat scheme.

  • study on a dual mode multi stage multi bed regenerative Adsorption Chiller
    Renewable Energy, 2006
    Co-Authors: Bidyut Baran Saha, Yoshinori Hamamoto, Shigeru Koyama, Kim Choon Ng, Atsushi Akisawa, Takao Kashiwagi
    Abstract:

    In this paper, a detailed parametric study on a dual-mode silica gel–water Adsorption Chiller is performed. This advanced Adsorption Chiller utilizes effectively low-temperature solar or waste heat sources of temperature between 40 and 95°C. Two operation modes are possible for the advanced Chiller. The first operation mode will be to work as a highly efficient conventional Chiller where the driving source temperature is between 60 and 95°C. The second operation mode will be to work as an advanced three-stage Adsorption Chiller where the available driving source temperature is very low (between 40 and 60°C). With this very low driving source temperature in combination with a coolant at 30°C, no other cycle except an advanced Adsorption cycle with staged regeneration will be operational. In this paper, the effect of chilled-water inlet temperature, heat transfer fluid flow rates and Adsorption–desorption cycle time effect on cooling capacity and COP of the dual-mode Chiller is performed. Simulation results show that both cooling capacity and COP values increase with the increase of chilled water inlet temperature with driving source temperature at 50 and 80°C in three-stage mode, and single-stage multi-bed mode, respectively. However, the delivered chilled-water temperature increases with chilled-water inlet temperature in both modes.

  • experimental study on performance improvement of a four bed Adsorption Chiller by using heat and mass recovery
    International Journal of Heat and Mass Transfer, 2006
    Co-Authors: Kim Choon Ng, Bidyut Baran Saha, Shigeru Koyama, Atsushi Akisawa, Xiaolin Wang, Anutosh Chakarborty, Takao Kashiwagi
    Abstract:

    The efficacy of a four-bed Adsorption Chiller has been studied experimentally with respect to a simple but yet effective passive heat and mass recovery schemes. It substantially improves the Adsorption Chiller COP by as much as 30% over a broad range of cycle time with a wide heat source, coolant and chilled water temperatures. Two schemes have been considered here: Firstly, only the mass recovery is achieved by pressure equalization between the concomitantly cooled adsorber and heated desorber, exploiting the intrinsic vapor-uptake potential by pressure swing that remains in the adsorbent at the end of a half-cycle. Secondly, when both the heat and mass recovery schemes are employed at a rating point of maximum cooling capacity, the Chiller COP could increase further to as much as 48%. These improvements are performed without additional hardware changes to the Adsorption Chiller.

  • experimental investigation on a novel four bed Adsorption Chiller
    Trace, 2003
    Co-Authors: Kim Choon Ng, Atsushi Akisawa, Xiaolin Wang, Takao Kashiwagi, Hui Tong Chua, Jin Bao Wang, Bidyut Baran Saha
    Abstract:

    A prototype multi-bed regenerative Adsorption Chiller with a novel four-bed operation mode has been designed, fabricated and tested. The rating tests are conducted under assorted ARI coolant, using a purpose-built rating. The 4.bed design exhibits superior heat extraction capability from the heat source as its "slave-first-then-master" arrangement permits individual bed to maximize energy utilization in a batch cycle. Overall system performance of Chiller is evaluated for various Adsorption-desorption cycle and switching time at assorted coolant inlet temperatures. For fair comparison, the 4-bed Chiller is also compared with that of a two-bed mode at the same working conditions.

  • performance evaluation of a low temperature waste heat driven multi bed Adsorption Chiller
    International Journal of Multiphase Flow, 2003
    Co-Authors: Bidyut Baran Saha, Yoshinori Hamamoto, K C A Alam, Shigeru Koyama, Ken Kuwahara, Atsushi Akisawa, Takao Kashiwagi
    Abstract:

    Abstract This study aims at improving the performance of thermally activated silica gel–water Adsorption refrigeration cycle by applying multi-bed scheme. In this paper, a three-bed non-regenerative silica gel–water Adsorption Chiller design is outlined along with the performance evaluation of the innovative Chiller. The three-bed Chiller will be able to work as high efficient single-stage Adsorption Chiller where driving source temperature is between 60 and 95 °C along with a coolant at 30 °C. The three-bed cycle comprises with three adsorber/desorber heat exchangers, one evaporator and one condenser. Waste heat or renewable energy sources will power the high temperature desorber. If two beds are in desorption mode, the hot water outlet from the lead desorber will drive the lag desorber before being released to ambient. This facilitates the maximum utilization of the waste stream. On the contrary, if two adsorber or desorber beds are in Adsorption mode, the cooling water outlet from the lead adsorber will cool down the lag adsorber. In this circumstance, two adsorber beds will be connected with the evaporator and will enhance evaporation. A cycle simulation computer program is developed to analyze the influence of operating temperatures (hot and cooling water temperatures, Adsorption/desorption cycle time) on cooling capacity and coefficient of performance (COP) of the innovative three-bed cycle in parallel flow configuration of the heat transfer fluids. The cycle simulation calculation indicates that the COP value of the three-bed Chiller is 0.38 with a driving source temperature at 80 °C in combination with coolant inlet and chilled water inlet temperatures at 30 and 14 °C, respectively. The delivered chilled water temperature is about 6 °C with this operation condition. Simulation results also show that from the two to three beds, waste heat recovery efficiency, η is boosted by about 35%.

J.y. Wu - One of the best experts on this subject based on the ideXlab platform.

  • theoretical research of a silica gel water Adsorption Chiller in a micro combined cooling heating and power cchp system
    Applied Energy, 2009
    Co-Authors: Shuanming Li, J.y. Wu
    Abstract:

    A novel micro CCHP system, which is based on a two bed silica gel-water Adsorption Chiller, is constructed in this work. To reveal the Chiller characteristic in this system, a transient model of the Adsorption Chiller is developed. According to the comparison of the simulated results and experimental data, the presented model shows a good performance in predicting the Chiller performance, with both stable and variable heat source temperature. With the analysis of simulated results, it is found that the cooling capacity and the coefficient of performance (COP) of the Chiller are influenced significantly by the average value and variation rate of electric load, as well as the average value of cooling load. The water tank also shows a great effect on the Chiller performance. To get better performance of the Chiller, the water tank should be adopted when the electric load is low or its variation rate is positive, and should not be utilized when the electric load is high or its variation rate is negative. A 500 L water tank is recommended in order to get better performance and acceptable start-up time. Furthermore, to get better performance as well as higher security, a cold accumulator should be adopted.

  • experimental study of Adsorption Chiller driven by variable heat source
    Energy Conversion and Management, 2008
    Co-Authors: D.c. Wang, X.l. Tian, Yong Wang, Jingkui Zhang, J.y. Wu
    Abstract:

    Abstract A silica gel–water Adsorption Chiller has been developed in recent years and has been applied in an air conditioning system driven by solar energy. The heat source used to drive the Adsorption Chiller is variable at any moment because the solar radiation intensity or the waste heat from engines varies frequently. An Adsorption cooling system may be badly impacted by a variable heat source with temperature variations in a large range. In this work, a silica gel–water Adsorption Chiller driven by a variable heat source is experimentally studied. The influences of the variable heat source on the performance of the Chiller are analyzed, especially for a continuous temperature increase process and a continuous temperature decrease process of the heat source. As an example, the dynamic characteristics of the heat source are also analyzed when solar energy is taken as the heat source of the Adsorption Chiller. According to the experimental results for the Adsorption Chiller and the characteristics of the heat source from solar energy, control strategies of the Adsorption Chiller driven by solar energy are proposed.

  • Experimental study of Adsorption Chiller driven by variable heat source
    Energy Conversion and Management, 2008
    Co-Authors: D.c. Wang, X.l. Tian, J.p. Zhang, Y.-j. Wang, J.y. Wu
    Abstract:

    A silica gel-water Adsorption Chiller has been developed in recent years and has been applied in an air conditioning system driven by solar energy. The heat source used to drive the Adsorption Chiller is variable at any moment because the solar radiation intensity or the waste heat from engines varies frequently. An Adsorption cooling system may be badly impacted by a variable heat source with temperature variations in a large range. In this work, a silica gel-water Adsorption Chiller driven by a variable heat source is experimentally studied. The influences of the variable heat source on the performance of the Chiller are analyzed, especially for a continuous temperature increase process and a continuous temperature decrease process of the heat source. As an example, the dynamic characteristics of the heat source are also analyzed when solar energy is taken as the heat source of the Adsorption Chiller. According to the experimental results for the Adsorption Chiller and the characteristics of the heat source from solar energy, control strategies of the Adsorption Chiller driven by solar energy are proposed. © 2007 Elsevier Ltd. All rights reserved.

  • an efficient solar powered Adsorption Chiller and its application in low temperature grain storage
    Solar Energy, 2007
    Co-Authors: R. Z. Wang, J.y. Wu, J. M. Shen, B. B. Zhang
    Abstract:

    Abstract A novel solar-powered Adsorption cooling system for low-temperature grain storage has been built, which consists of a solar-powered water heating system, a silica gel–water Adsorption Chiller, a cooling tower and a fan coil unit. The Adsorption Chiller is composed of two identical Adsorption units, each of them containing an adsorber, a condenser, and an evaporator/receiver. The two water evaporators have been incorporated into one methanol evaporator by the use of the concept of a gravity heat pipe. In order to improve the system efficiency and achieve continuous cooling production, the adsorbers are operated out-of-phase, and heat and mass recovery processes have been used. During the period from July to September of 2004, the system was put into experimental operation to cool the headspace (i.e., the air volume above the grain) of a grain bin. Three months of operation showed promising performance. The Chiller had a cooling power between 66 and 90 W per m2 of collector surface, with a daily solar cooling coefficient of performance (COPsolar) ranging from 0.096 to 0.13. The electric cooling COP was between 2.6 and 3.4.

  • experimental investigation of Adsorption Chiller for micro scale bchp system application
    Energy and Buildings, 2007
    Co-Authors: Y Huangfu, J.y. Wu, R. Z. Wang
    Abstract:

    Building cooling, heating and power (BCHP), is an attracting cogeneration system for its economic and environmental friendly qualities. Therefore, it is meaningful to develop Micro-scale BCHP (MBCHP) system based on Adsorption Chiller and internal combustion gas engine for the use of residential and light commercial buildings. To guide the optimum matching and operation of Adsorption Chiller in MBCHP system correctly, this paper deals with the performance of Adsorption Chiller under varying heating conditions. Experimental results show that the value of COP is high in the operation mode of varying hot water inlet temperature with mass recovery in no heating pattern (VTNH). With the hot water inlet temperature of 65 °C, the value of COP is as high as 0.40 in VTNH mode. Under electricity output conditions from 6.0 to 8.3 kW in MBCHP system, VTNH mode is especially preferred when cooling demand is with priority.