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1.
R.Z. Wang  Z.Z. Xia  L.W. Wang  Z.S. Lu  S.L. Li  T.X. Li  J.Y. Wu  S. He 《Energy》2011,36(9):5425-5439
Adsorption refrigeration and heat pump systems have been considered as important means for the efficient use of low-grade thermal energy of 60–150 °C. Sorption systems are merely thermodynamic systems based on heat exchangers, and therefore a good design to optimize heat and mass transfer with reaction or sorption processes is very important, for which the notable technique is the use of expanded graphite to improve both heat and mass transfer in the chemisorption beds. Studies have also shown the need to enhance the heat transfer in adsorption bed by matching with the efficient heat transfer of thermal fluids. Heat pipes and good thermal loop design coupled with adsorption beds could yield higher thermal performance of a sorption system. A novel design with passive evaporation, known as rising film evaporation coupled with a gravity heat pipe was introduced for high cooling output. It has also been shown that the performance of traditional heat and mass recovery in the sorption systems is limited, and novel arrangement of thermal fluid and refrigerant may improve the performance of sorption systems. Based upon the above researches, various sorption systems have been developed, and high performances have been reached.  相似文献   

2.
The purpose of this paper is to present the performance analysis of a multifunction heat pipe type adsorption ice maker with activated carbon–CaCl2 as compound adsorbent and ammonia as refrigerant. For this test unit, the heating, cooling and heat recovery processes between two adsorbent beds are performed by multifunction heat pipes. A novel mass and heat recovery adsorption refrigeration cycle is developed. When mass recovery process is implemented before heat recovery process, the performance of the cycle with novel mass and heat recovery processes is much better than that for the cycle with the conventional mass and heat recovery processes. The experimental results show that the former cycle can increase the coefficient of performance (COP) and specific cooling power (SCP) by more than 17% compared with the latter cycle. In comparison with the basic adsorption cycle, the mass and heat recovery cycle can enlarge the cycled refrigerant mass and reduce the power consumption of boiler; the COP and SCP were improved by more than 11% when the mass recovery time was 20 s, while at the optimal mass recovery time of 40 s, the COP improvements for conventional and novel mass and heat recovery cycles are 43.8% and 68.7%, respectively. It was concluded that the novel mass and heat recovery processes are more beneficial to improve the performance of adsorption refrigeration system in comparison with the conventional mass and heat recovery processes.  相似文献   

3.
In this paper we present the study of adsorption refrigerator which use an activated carbon-pair ammonia. The ability of activated carbons to adsorb large mass of ammonia makes them ideal for use in adsorption refrigeration and pump systems. These systems have not reasonable efficiency. In order to make these systems economically viable, their size must be reduced. This implies a need for a rapid heating and cooling the adsorbent/refrigerant pair. However, the main problems to be overcome is related to the poor heat transfer in the adsorbent bed. So, it is necessary to study and understand the heat and mass transfer within the bed and to improve it. A detailed model of heat and mass transfer into the generator has been developed. For a given heat flux, temperature and adsorbed mass have been computed in every point at each step time along the adsorbed bed (generator). Experimental installation simulating an adsorption machine working within a temperature ranging from 20 to 250 °C and pressure ranging from 0 to 2.5 × 106 Pa, allows for identification of the generator's equivalent thermal conductivity and internal heat transfer coefficient. These two parameters are then used to simulate thermal performance of a design whose features include the insertion of stainless steel water heat pipe (HP's) condensers into the generator. The HP's evaporator heat input is of solar origin using a compound parabolic collector (CPC). Nominal Solar coefficient of performance, COPs =14.37% obtained through both Adimensional Exergy Loss (AEL), and COP study, shows the competitiveness of the proposed design.  相似文献   

4.
Research and development of consolidated adsorbent for adsorption systems   总被引:1,自引:0,他引:1  
Adsorption heat pump and refrigeration systems are noiseless, non-corrosive and environment friendly. For these reasons the research activities in this sector are still increasing to solve the crucial points that make these systems not yet ready to compete with the well-known vapor compression system. There is an increasing interest in the development and use of adsorption chillers due to their various economic and impressive environmental benefits, enabling solar energy or waste heat to be used for applications such as district networks and cogeneration plants. In order to increase the cooling power, much effort has been devoted to enhance materials heat transfer properties. Consolidated adsorbent could be the solution. This paper provides a literature review on current progress of consolidated adsorbent for adsorption systems. A number of consolidated technologies of adsorbent are discussed. The related work at our laboratory is also discussed.  相似文献   

5.
L.W. Wang  H.S. Bao  R.Z. Wang 《Renewable Energy》2009,34(11):2373-2379
In order to study the refrigeration performances of the resorption refrigeration technology, the resorption working pair of BaCl2–MnCl2–NH3, which has the similar working requirements for the heat source and cooling source, and also could satisfy the similar refrigeration requirements with the adsorption working pair of CaCl2–NH3, is studied by simulation and experiments. In the simulation the mass transfer resistance is not considered for the systems, and the refrigeration performances related with heat transfer performances are studied, results show that the resorption refrigeration system has a higher refrigeration power and COP (coefficient of the refrigeration performance) because the refrigeration effect is generated by the reaction heat compared to the latent heat of evaporation. After the simulation the experimental test unit is constructed, and the experimental data are analyzed. Results show that the resorption rate is influenced by the critical mass transfer performance very much, and the refrigeration performance is lower than that of adsorption system. The resorption system also has the problem of the larger refrigeration power loss for the reason of the sensible heat requirement of low temperature adsorber. How to improve the mass transfer performance of resorption system and decrease the influence on the refrigeration power by the sensible heat requirement of low temperature adsorber will be the key research directions for the application of resorption refrigeration systems.  相似文献   

6.
The study deals with an advanced four-bed mass recovery adsorption refrigeration cycle driven by low temperature heat source. The proposed cycle consists of two basic adsorption refrigeration cycle. The heat source rejected by one cycle is used to power the second cycle. Due to the cascading use of heat and cooling source, all major components of the system maintain different pressure levels. The proposed cycle utilize those pressure levels to enhance the refrigeration mass circulation that leads the system to perform better performances. The performance of the proposed cycle evaluated by the mathematical model at equilibrium condition and compared with the performance of the basic two-bed adsorption refrigeration cycle. It is seen that the cooling effect as well as COP of the proposed cycle is superior to those of the basic cycle. The performances of the cycle are also compared with those of the two-stage cycle. Results also show that though the cooling effect of the proposed cycle is lower than that of two-stage cycle for heat source temperature less than 70 °C, the COP of the cycle, however, is superior to that of two-stage cycle for heat source temperature greater than 60 °C.  相似文献   

7.
A new transient two-dimensional model for the simulation of a combined heat and mass recovery adsorption cooling cycle based on the zeolite NaX/water working pair is proposed in this paper. The model describes the transfer phenomena in the adsorber in detail and is solved by control volume method. Internal and external mass transfer limitations which are neglected by many researchers are considered in the model since they have significant effects on the performance of the adsorption cooling cycle. The numerical results show that the combined heat and mass recovery cycle between two adsorbent beds can increase the coefficient of performance (COP) of an adsorption cooling system by more than 47% compared to the single bed cycle. This numerical model can be used in system optimization and design of adsorption cycles.  相似文献   

8.
固体吸附式制冷的关键技术研究   总被引:21,自引:6,他引:15  
描述吸附容量的D-A方程、吸附床内的传热传质、新型热力循环的潜力与可行性、吸附系统的技术经济性和优化控制、实际吸附循环理论以及双效/多效吸附式制冷等是吸附式制冷尚需进行研究的基础课题。本文对固体吸附式制冷机的关键技术进行了探讨。  相似文献   

9.
The key component of a solar adsorption refrigeration unit is the adsorber packed with an adsorbent such as zeolite, active carbon and CaCl2. One essential problem faced is the poor heat transfer in adsorbers, which strongly influences the performance of the system. Poly-aniline, with the advantage of superior thermal conduction, was introduced into an adsorber to increase the thermal conductivity of the adsorbents. As the thermal conductivity coefficient of adsorbent in the adsorber is enhanced, the thermal contact resistance of the interface becomes a significant proportion and needs to be improved. The heat transfer of solid interfaces, particularly the effects of the adsorbent granule or block with rough surfaces, is studied in this paper. Methods for decreasing the contact resistance using spreading adhesive or exerting pressure on the interface are presented and analysed. A test facility and relevant procedure are developed to measure the effects of different interfaces on the contact resistance. The heat transfer at the interface between the copper surface and the adsorbent granule or block is investigated, and its effect in improving the thermal performance of the adsorber in solar adsorption refrigeration is compared. The experimental results show that exerting pressure or spreading adhesive on the interface can reduce the contact resistance significantly without affecting the mass transfer of the adsorbent in an adsorber.  相似文献   

10.
S.G. Wang  R.Z. Wang   《Renewable Energy》2005,30(4):589-600
Modern large and fast ocean fishing vessels include mechanical refrigeration, but all of them consume precious fuel or electricity to achieve refrigeration. Fishing vessels with tonnage at about 100 tons cannot attach compressor-icemaker onboard because of their small horsepower of diesel engine. These vessels always have to carry a lot of ice for caught fish preservation. At the same time, waste heat dissipated in the hot exhaust gases in most of the fishing vessels is rejected to the atmosphere. At present, some effort has been devoted to the utilization of the vast amount of the waste energy for refrigeration. In this paper, several types of refrigeration technology in fishing vessels are introduced, such as vapor-compression refrigeration systems, heat recovery systems to power absorption refrigeration plant, adsorption systems for producing chilled water, and adsorption icemaker systems, especially an adsorption icemaker prototype in our laboratory. The better perspectives of applications for the lattermost exist in fishing vessels.  相似文献   

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