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The aims of this paper is to indicate that the non-equilibrium adsorption testing results is more suitable for prediction of real refrigeration performance than equilibrium data. Therefore, a test unit is constructed to test the non-equilibrium performance of different composite adsorbents. The adsorption and desorption quantity are measured and calculated by smart differential pressure transmitter. The non-equilibrium adsorption performances of working pair of Manganese chloride–ammonia, Calcium chloride–ammonia and Ammonium chloride–ammonia are investigated respectively. Results show that hysteresis phenomena happens obviously in non-equilibrium desorption process, which is related with dual variables rather than single variable. Based on the testing results, resorption refrigeration performance is analyzed, in which Manganese chloride is used as high temperature salt (HTS), and Calcium chloride, Ammonium chloride are selected as low temperature salt (LTS) for comparison. Results show that the highest COP and SCP for resorption refrigeration are about 0.272 and 45.6 W/kg, respectively. Performance of Manganese chloride–Calcium chloride and Manganese chloride–Ammonium chloride working pairs are much lower when compared with theoretical data. [ABSTRACT FROM AUTHOR]

Activated carbon–ammonia multi-stage adsorption refrigeration cycle was analyzed in this article, which realized deep-freezing for evaporating temperature under −18 °C with heating source temperature much lower than 100 °C. Cycle mathematical models for single, two and three-stage cycles were established on the basis of thorough thermodynamic analysis. According to simulation results of thermodynamic evaluation indicators such as COP (coefficient of performance), exergetic efficiency and cycle entropy production, multi-stage cycle adapts to high condensing temperature, low evaporating temperature and low heating source temperature well. Proposed cycle with selected working pair can theoretically work under very severe conditions, such as −25 °C evaporating temperature, 40 °C condensing temperature, and 70 °C heating source temperature, but under these working conditions it has the drawback of low cycle adsorption quantity. It was found that both COP and exergetic efficiency are of great reference value in the choice of cycle, whereas entropy production is not so useful for cycle stage selection. Finally, the application boundary conditions of single-stage, two-stage, and three-stage cycles were summarized as tables according to the simulation results, which provides reference for choosing optimal cycle under different conditions. [ABSTRACT FROM AUTHOR]

Activated carbon–ammonia multi-stage adsorption refrigeration cycle was analyzed in this article, which realized deep-freezing for evaporating temperature under −18 °C with heating source temperature much lower than 100 °C. Cycle mathematical models for single, two and three-stage cycles were established on the basis of thorough thermodynamic analysis. According to simulation results of thermodynamic evaluation indicators such as COP (coefficient of performance), exergetic efficiency and cycle entropy production, multi-stage cycle adapts to high condensing temperature, low evaporating temperature and low heating source temperature well. Proposed cycle with selected working pair can theoretically work under very severe conditions, such as −25 °C evaporating temperature, 40 °C condensing temperature, and 70 °C heating source temperature, but under these working conditions it has the drawback of low cycle adsorption quantity. It was found that both COP and exergetic efficiency are of great reference value in the choice of cycle, whereas entropy production is not so useful for cycle stage selection. Finally, the application boundary conditions of single-stage, two-stage, and three-stage cycles were summarized as tables according to the simulation results, which provides reference for choosing optimal cycle under different conditions. [ABSTRACT FROM AUTHOR]

Energy conversion technologies, especially for power generation and refrigeration technologies driven by the low temperature heat, are gathering the momentum recently. This paper presents a novel resorption system for electricity and refrigeration cogeneraion. Compared with adsorption refrigeration system, resorption refrigeration is characterized as safety and simple structure since there is no ammonia liquid in the system. The cogeneration system is mainly composed of three HTS (high temperature salt) unit beds; three LTS (low temperature salts) unit beds, one expander, three ammonia valves, two oil valves, four water valves and connection pipes. Chemical working pair of MnCl 2 –CaCl 2 –NH 3 is selected. Since scroll expander is suitable for small type power generation system, it is chosen for expansion process. 4.8 kg MnCl 2 and 3.9 kg CaCl 2 impregnated in expanded natural graphite treated with sulfuric acid (ENG-TSA) are filled in the cogeneration system. Experimental results show that maximum cooling power 2.98 kW is able to be obtained while maximum shaft power is about 253 W with 82.3 W average value. The cogeneration system can be utilized for the heat source temperature lower than 170 °C. Total energy efficiency increases from 0.293 to 0.417 then decreases to 0.407 while exergy efficiency increases from 0.12 to 0.16. [ABSTRACT FROM AUTHOR]

Highlights: [•] AC corrosion was investigated by AC voltammetry technique. [•] Corrosion potential shift negatively with the increase of AC amplitude. [•] Corrosion potential shift negatively with the decrease of AC frequency. [•] The specific adsorption of Cl− decreases with the increase of AC voltage amplitudes. [ABSTRACT FROM AUTHOR]

Properties such as thermal conductivity, permeability, adsorption concentration of adsorbents are paramount for adsorption refrigeration. A novel consolidated composite CaCl2 with the matrix of expanded natural graphite treated with sulfuric acid (ENG–TSA) was investigated and the samples were developed according to different mass ratio of salt and different density. Results indicate that samples have very perspective heat and mass transfer performance. The highest thermal conductivity was 88.1 W/(m K), which is 22 times higher than that with the matrix of expanded natural graphite (ENG) and 400 times higher than ordinary granular CaCl2. Permeability of adsorbent was between 9.31 × 10−10 to 3.05 × 10−14 m2 while the density ranged between 300 and 500 kg/m3. Adsorption performance of composite CaCl2 was tested, and the results showed that for the samples with different density and salt mass ratio adsorption quantity ranged between 0.364 g/g to 0.4492 g/g while the cooling temperature and evaporating temperature changed from 25 to 35 °C and −10 to 15 °C, respectively. Furthermore, under the conditions of same heat source, cooling water and evaporating temperature, the heating time for the tube adsorber of composite CaCl2 with ENG–TSA as the matrix was almost 2.5 times less than that with ENG as the matrix. [ABSTRACT FROM AUTHOR]

For refrigeration condition in order to choose an optimal consolidated composite activated carbon (AC), the thermal conductivity, permeability, equilibrium adsorption performance, and non-equilibrium adsorption performance were studied. Six samples of three types of adsorbents (consolidated AC with expanded natural graphite treated with sulfuric acid (ENG-TSA), consolidated AC with expanded natural graphite (ENG) and granular AC) with different density and different grain size were produced and compared. Experiments showed that the thermal conductivity and permeability of consolidated AC with ENG-TSA are between 6.75 to 7.45W/mK and 2.00×10−12 to 1.00×10−11 m2, respectively, when the density is ranged between 350kg/m3 and 450kg/m3. The study on the equilibrium and non-equilibrium adsorption performance indicated that the addition of ENG-TSA helps to improve the concentration swing. The cycle time of consolidated AC with ENG-TSA decreases significantly compared with that of consolidated AC with ENG and granular AC. For the optimal results from the matrix of ENG-TSA although the bulk density of AC decreases, the volume cooling power is 30% improved in comparison with the results of granular AC because the cycle time decreases significantly. [ABSTRACT FROM AUTHOR]

Abstract: A novel two-stage adsorption freezing machine, which is powered by the heat source with the temperature below 100°C was developed. The composite adsorbents of CaCl2 and BaCl2 developed by the matrix of expanded natural graphite were chosen as adsorbents. The performance of the system was tested, and the results showed that the system can generate the refrigerating power at −15°C for the coolant temperature of 25°C when the temperature of heat source is as low as 75°C. For the heat source of 85°C and the coolant temperature of 25°C, the optimal coefficient of performance (COP) and specific cooling power (SCP) at −15°C refrigeration are 0.127 and 100Wkg−1, respectively. COP and SCP increased with the increasing heat source temperature and decreased with the decreasing evaporating temperature; the influence of evaporating temperature is not as significant as that of the regeneration temperature. [Copyright &y& Elsevier]

Abstract: A heat pipe type adsorption refrigerator system is proposed and investigated, which can be powered by solar energy or waste heat of engine. The study assesses the performance of compound adsorbent (CaCl2 and activated carbon)–ammonia adsorption refrigeration cycle with different orifice sets and different mass and heat recovery processes by experimental prototype machine. Specific cooling power (SCP) and coefficient of performance (COP) were calculated with experimental data to analyze the influences of operating condition. The results show that the jaw opening of the hand needle nozzle can influence the adsorption performance obviously and the thermostatic expansion valve (TEV) is effective in the intermediate cycle time in the adsorption refrigeration system. The SCP of the cycle with the mass-heat recovery together (combined recovery process) is superior to that of the conventional cycles with mass recovery or heat recovery independently. [Copyright &y& Elsevier]

Abstract: Composite adsorbents, comprising activated carbon and expanded natural graphite, have been developed, and their thermal conductivity, permeability and adsorption performance were tested. The thermal conductivity varied with the ratio of activated carbon to expanded natural graphite. Thermal conductivity increased as the ratio of expanded graphite increased. Considering that the density of activated carbon for the composite adsorbent should not be lower than 200 kg/m3, otherwise the volumetric cooling capacity would be unacceptably low, the highest thermal conductivity obtained from experiments was 2.47 W m−1 K−1. The permeability was also measured, and the best result obtained was 4.378 × 10−12 m2. In order to evaluate the influence of heat and mass transfer on adsorption performance, the adsorption rate was tested using a Rubotherm magnetic suspension balance, and results showed that for the freezing conditions lower than −10 °C the performance of granular activated carbon was better than that of solidified adsorbent because of the reduced mass transfer of ammonia at low saturated pressure. The adsorption performance of consolidated adsorbents increased rapidly when the evaporating temperature was higher than −10 °C. When the evaporating temperature was 8 °C, the adsorption rate of consolidated adsorbent was improved by 29% if compared with that of granular adsorbent. [Copyright &y& Elsevier]

Abstract: 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. [Copyright &y& Elsevier]

Abstract: Solid sorption refrigeration is a type of environmental benign and energy saving technology and the sorbents utilized can be divided into physical, chemical and composite sorbents, according to the nature of the forces involved in the adsorption process. The types, characteristics, advantages and disadvantages of different adsorbents, refrigerants and working pairs are summarized in this paper, together with the models that describe the adsorption equilibrium. Moreover, some of the procedures to prepare composite adsorbents are presented. The application of different working pairs for different situations is related with the adsorption heat, the adaptability to the driving temperature and to the desired working pressure. The methods to measure the adsorption quantity of different working pairs are compared, and future research directions of adsorption working pairs are also analyzed. [Copyright &y& Elsevier]

Abstract: The available adsorption working pairs applied to adsorption refrigeration system, which utilize activated carbon as adsorbent, are mainly activated carbon–methanol, activated carbon–ammonia, and composite adsorbent–ammonia. The adsorption properties and refrigeration application of these three types of adsorption working pairs are investigated. For the physical adsorbents, consolidated activated carbon showed best heat transfer performance, and activated carbon–methanol showed the best adsorption property because of the large refrigerant amount that can be adsorbed. For the composite adsorbents, the consolidated composite adsorbent with mass ratio of 4:1 between CaCl2 and activated carbon, showed the highest cooling density when compared to the granular composite adsorbent and to the merely chemical adsorbent. The physical adsorption icemaker that employs consolidated activated carbon–methanol as working pair had the optimum coefficient of refrigeration performance (COP), volume cooling power density (SCP v ) and specific cooling power per kilogram adsorbent (SCP) of 0.125, 9.25kW/m3 and 32.6W/kg, respectively. The composite adsorption system that employs the consolidated composite adsorbent had a maximum COP, SCP v and SCP of 0.35, 52.68kW/m3 and 493.2W/kg, respectively, for ice making mode. These results are improved by 1.8, 4.7 and 14 times, respectively, when compared to the results of the physical adsorption icemaker. [Copyright &y& Elsevier]

Abstract: Adsorption and desorption were performed on a compound adsorbent composed of and activated carbon in cycles both with and without mass recovery and the performances obtained were compared with those of equilibrium adsorption. Experimental results of the cycles without mass recovery carried out on an adsorption refrigeration unit yielded performances that were slightly less than those of equilibrium adsorption. The adsorption performances of the cycle with mass recovery were measured to be much better than those of the cycle without mass recovery. At of evaporating temperature, the cycle adsorption capacity was as high as 0.78kg/kg for the cycle with mass recovery while it was only 0.55kg/kg for the cycle without mass recovery. The average adsorption/desorption rate of the cycle with mass recovery, which was 0.031(kg/kg)/min, has been improved by 47.6% compared with that of the cycle without mass recovery. Research on the cycle adsorption capacity at different evaporating temperatures showed that the improvement of cycle adsorption capacity, with mass recovery, was higher under the condition of lower evaporating temperature. At evaporating temperature, the mass recovery operation had improved the adsorption capacity by 78% compared with the cycle without mass recovery. In addition, refrigeration performances for the cycles with and without mass recovery at an evaporating temperature of were studied. Compared with the results of the cycle without mass recovery, SCP (specific cooling power) and COP (coefficient of refrigeration performance) have been improved by 48.6% and 54.5%, respectively, when mass recovery is performed. [Copyright &y& Elsevier]

Abstract: An activated carbon–methanol adsorption refrigeration system is tested, in which the performances of a granular bed and a solidified bed are compared. Results are presented and the effects of heat and mass transfer are analyzed. It is proved that the coefficient of performance of refrigeration (COP) is increased by 60% if heat and mass recovery is used for a two-granular-bed system. It is also shown that the heat transfer in a solidified bed is much better than that in a granular bed, but the mass transfer in a solidified bed is critical. Two new adsorbers are designed after analyzing the influence of mass transfer on the performance of the solidified bed, and the arrangement of mass transfer channels is fully taken into account. The simulation of this new designed ice maker shows that the optimal cycle time is about 35min, and the corresponding specific cooling power (SCP) is SCP=35W/kg at −10°C evaporating temperature. The new designed system (two adsorbers, each containing 60kg activated carbon) is set up and tested; its evaporating temperature is as low as about −15°C, and its optimal ice production is about 20kg/h. [Copyright &y& Elsevier]

Abstract: A new type of adsorber for an adsorption ice maker on fishing boats, which uses a compound adsorbent (activated carbon and CaCl2) and ammonia working pair, is designed. This type of heat pipe adsorber solves the problem of incompatibility between ammonia, copper, seawater and steel. The heating/cooling power for the adsorption/desorption process of the adsorbent, which is required to be transferred by one heat pipe in the adsorber, is computed by the test results of the adsorbent, and the heat transfer performance of one heat pipe in the adsorber is simulated according to the theory of the two phase closed thermosyphon. The heat transfer performance of the heat pipe can meet the heat demands for adsorption/desorption of the adsorbent when the evaporating temperature is −15°C and the cycle time is 10min. A test unit is set up to test the heating/cooling performance of the heat pipe type adsorber, and the experimental results are coincident with the simulation. The performance of a two bed adsorption ice maker with heat pipe adsorbers is predicted, and the cooling power is about 17.1–17.8kW at the evaporating temperature of −15°C and cycle time of 10min with mass recovery between two 29kg compound adsorbent beds. [Copyright &y& Elsevier]

Different adsorbents, such as physical, chemical and composite adsorbents are analyzed. Three types of working pairs, activated carbon–methanol, chemical adsorbent-ammonia and composite adsorbent-ammonia can be used for adsorption ice makers on fishing boats. The advantages, disadvantages and performances of three types of adsorption ice makers, with activated carbon–methanol, CaCl2–NH3 and compound adsorbent (made by CaCl2 and activated carbon)-NH3 as adsorption pairs, are compared at the condition of two bed systems. The activated carbon–methanol ice maker shows the advantage of reliable safety, and the composite adsorption ice maker shows the best adsorption performance. The cooling power of 20.32 kW can be obtained from the composite adsorption ice maker when the volume for each adsorber is 0.288 m3, which is about 10 times that of the physical adsorption ice maker and 1.38 times that of the chemical adsorption ice maker. [Copyright &y& Elsevier]

Heat recovery is an effective way to improve adsorption refrigeration system performance due to its easy realization and obvious improvement. Three kinds of heat recoveries (circular heat recovery is complete type and serial and passive heat recoveries are part type) have been applied in recent adsorption refrigerators. Theoretical analysis of three heat recovery methods has been done and results show that serial and passive heat recoveries (part type) are more optimal than circular heat recovery (complete type) when manufacture and cost are considered. Furthermore, a CFD model of a fin-tube type adsorber has been established and simulations of serial and passive heat recoveries have been done. The simulation results show that recovery time of passive heat recovery has an effective range whose value is approximately double of optimum recovery time. Thus, serial heat recovery is more reliable than passive heat recovery. Besides, Optimum recovery time of both serial and passive heat recoveries is approximately equal to the ratio of tube length to heating/cooling flow rate. Contribution distribution of recovered heat has also been analyzed. And the results show that contributions of fluid and tube regions are respectively 89%∼94% and 5%∼10% while contributions of adsorbent and fin regions are negligible. [ABSTRACT FROM AUTHOR]

An adsorption icemaker with energy storage system is proposed for the utilization of medium temperature solar energy. In this system, the solar energy collected by parabolic trough collector (PTC) was used to provide the heat source for the adsorption icemaker. The performance of the icemaker is tested and the experimental results showed that the highest COP reached 0.15 while the COPsr could be 0.08 and the ice making capacity was 50 kg per day with 20 m2 PTC and 30 kg compound adsorbent (calcium chloride + activated carbon) when the desorption temperature, condensing temperature and the direct normal solar radiation were 105 °C, 30 °C and 3 kWh/day·m2, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Permeability and thermal conductivity test units were designed to study the heat and mass transfer performance of compact chemical and physical adsorbents, i.e. compact CaCl2 and activated carbon (AC) using expanded natural graphite (ENG) as host matrix. The thermal conductivity was studied by steady-state heat source method and the permeability was tested with nitrogen as a gas source. For the compact CaCl2 adsorbents, results show that permeability and thermal conductivity vary with the ratio of ENG and the density of compact adsorbents. The value of permeability is 10-13 ∼10-11 m2 when the density of compact sample change from 400kg/m3 to 550kg/m3, and it keeps increasing linearly with the less ratio of ENG. The value of thermal conductivity is 1.08W/(m·K), which is increased by 5 times compared with granular CaCl2 when the density is 550kg/m3 and the ratio of ENG is the minimum value of 16.7%. The compact physical adsorbent of AC with ENG as matrix has the highest thermal conductivity of 2.61W/(m·K) when the ratio between ENG–AC is 1.5:1. Similarly, thermal conductivity drops down with the ratio of ENG decreasing. When the ratio of ENG reaches the minimum ratio of 28.6%, the thermal conductivity is 2.08W/(m·K), which is increased by 5.8 times if compared with the result of granular AC, and corresponding permeability is 5.16×10-11 m2. The thermal conductivity and permeability of compact physical adsorbent of AC are all better than the values for the compact chemical adsorbent of CaCl2. [Copyright &y& Elsevier]

Abstract: 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. [Copyright &y& Elsevier]

Abstract: A split heat pipe adsorption ice maker, which uses a solidified compound adsorbent (calcium chloride and activated carbon)-ammonia as working pair, is studied. The application of split heat pipe technology in this system (ice maker for fishing boat powered by waste heat of exhaust gases from diesel engine) solves the corrosion problem caused by using seawater to cool the adsorber directly. Therefore, the adsorbers can be cooled or heated by the working substance of the heat pipe in the adsorption or desorption state, respectively. There are two adsorbers in the adsorption ice maker, and each adsorber contains 2.35kg compound adsorbent in which the mass of calcium chloride is 1.88kg. The mass transfer performance and volume cooling density of the chemical adsorbent are greatly improved by the use of the compound adsorbent. Water is chosen as the working substance of the heat pipe due to its high cooling power in comparison with the experiments performed using acetone as working substance. When the cycle time is 70min, the average SCP of ice making is about 329.8–712.8W/kg calcium chloride with heat and mass recovery, which is approximately 1.6–3.5 times that of the best results of a conventional chemical adsorption ice maker. [Copyright &y& Elsevier]

Abstract: To improve the performance of the adsorption refrigeration of CaCl2–ammonia adsorption system, activated carbon has been distributed uniformly in the mass of CaCl2, thereby helping to enhance mass transfer and uplift the cooling power density. A multifunctional heat pipe adsorption refrigerator, in which activated carbon-CaCl2 is used as compound adsorbent and ammonia as refrigerant, is designed. Water and acetone are used as working liquids for the heat pipe. This paper presents a study on the adsorption refrigeration performances of this adsorption refrigerator under two different working conditions, ice-maker for fishing boat driven by the waste heat from exhaust gases, and solar ice-maker driven by solar water heating. The obtained average SCP (specific cooling power) and the COP (coefficient of performance) of the refrigerator were measured to be 770.4W/kg and 0.39 at about −20°C of evaporating temperature for the former working condition, and they were 161.2W/kg and 0.12 at about −15°C of evaporating temperature for the later working condition. [Copyright &y& Elsevier]

Abstract: In this paper, an innovative target-oriented desorption methodology for decreasing the regeneration temperature of solid–gas thermochemical sorption refrigeration system is presented. This method uses a two-stage desorption thermodynamic cycle with two different reactive salts to decrease the overall driving heat source temperature. The working principle of the proposed desorption methodology is based on the different thermochemical equilibrium characteristics of reactive salts. Experimental verification showed that the proposed two-stage desorption methodology is feasible and effective in lowering the regeneration temperature of solid–gas thermochemical sorption refrigeration system. Moreover, the extent to which the regeneration temperature is lowered can be regulated by choosing the appropriate secondary reactive salt according to the available driving heat source temperature. The presented target-oriented desorption methodology can contribute to the widening of the scope of application of thermochemical sorption refrigeration technology utilizing low-grade thermal energy or renewable energy. [Copyright &y& Elsevier]

Abstract: A combined double-way chemisorption refrigeration system was described and investigated, and the experimental test unit was built, which consists of two adsorption beds: one high-temperature salt bed (HTS bed), which is filled with manganese chloride; and one low-temperature salt bed (LTS bed), which is filled with barium chloride. Moreover, the working performance of double-way chemisorption refrigeration cycle was studied. This cycle uses only one heat input to get two cold outputs, one of which comes from the evaporation heat produced by the refrigerant during the adsorption process, and another of which is from decomposition reaction heat consumed by LTS during the resorption process. The experimental results showed that the coefficient of performance (COP) and specific cooling power (SCP) were 0.703 and 225 W kg−1 respectively at the refrigeration temperature of 15 °C, regeneration temperature of 160 °C and heat sink temperature of 30 °C. Also, the relation between the average global conversion and the COP value were found and analyzed. And the choice of salts and optimum reaction time were discussed either. [Copyright &y& Elsevier]

Abstract: A novel CaCl2/expanded graphite-NH3 adsorption refrigerator is developed and tested. Only three valves are installed in this refrigerator and they all work at the same positive pressure condition, so the operating reliability of the refrigerator is greatly improved. The experimental results show that the refrigerating power QCP, COP, SCP, electricity COPEl, and volume refrigerating density QCP-V of the refrigerator are 11.4kW, 0.27, 422.2W/kg, 32.6 and 57kW/m3, respectively, under the following conditions: the temperature of heating vapor is from 120°C to 140.3°C, the cooling water temperature is 25°C, the evaporation temperature is −15°C, the heating/cooling time is 25min including 45s mass recovery time. The SCP and volume refrigerating density of this refrigerator are about 1.8times and 1.5times that of the maximum of the former test results by other researchers. [Copyright &y& Elsevier]

Abstract: A combined double-way thermochemical sorption refrigeration thermodynamic cycle was proposed and tested. Both adsorption refrigeration and resorption refrigeration processes were combined in order to improve the system performance. Two different consolidated composite materials were used as the reactive sorbents and ammonia was used as the refrigerant. Experimental results showed that a system operating with such proposed cycle can have two useful cold productions during one cycle at the expense of only one heat input at high temperature. The average specific cooling power (SCP) during the adsorption refrigeration phase was 301Wkg−1. Analysis of the experimental data showed that the driving equilibrium drop during the resorption process was much lower than that during the adsorption process, when the cold production temperature was similar. The proposed combined double-way sorption cycle has a larger cooling capacity per unit of heat input and the maximum theoretical coefficient of performance (COP) is 1.24 when MnCl2 and BaCl2 are used as the reactive sorbents. [Copyright &y& Elsevier]

Abstract: An innovative combined double-way chemisorption refrigeration cycle based on adsorption and resorption processes is presented. Two different reactive salts were used as sorbents and ammonia was utilized as the refrigerant in the proposed cycle. The useful cold was obtained from the evaporation heat of the refrigerant during the adsorption process and from the reaction heat of the low-temperature salt during the resorption process. The proposed combined double-way cycle has a distinct advantage of higher coefficient of performance (COP) in comparison with conventional adsorption cycle or resorption cycle. Experimental verification indicated that the advanced combined double-way cycle is feasible for refrigeration application, and the ideal COP of the basic cycle was about 1.24. Theoretical results showed that the proposed combined double-way cycle could improve COP by 167% and 60% when compared with conventional adsorption cycle and resorption cycle, respectively. [Copyright &y& Elsevier]

Abstract: The performance of a solid sorption icemaker is investigated. CaCl2/activated carbon was used as compound adsorbent and ammonia was employed as adsorbate. The influence of operating conditions (cooling water temperature, mass recovery and heat pipe heat recovery, etc.) on the mass of ice, SCP (specific cooling power) and COP (coefficient of performance) was experimentally assessed. At the desorption temperature of 126°C, cooling water temperature of 22°C, ice produced temperature of −7.5°C, 40s of mass recovery and 2min of heat pipe heat recovery, the mass of ice, SCP and COP values are 17.6kg/h, 369.1W/kg and 0.2, respectively. [Copyright &y& Elsevier]

Abstract: Adsorption performances and thermal conductivity were tested for three types of adsorbent: Pure CaCl2 powder, simple composite adsorbent and consolidated composite adsorbent. The simple composite adsorbents show better adsorption performance because the additive of expanded graphite in CaCl2 powder has restrained the agglomeration phenomenon in adsorption process and improved the adsorption performance of CaCl2. The consolidated composite adsorbent are suitable to be used as adsorbent for ice maker on fishing boats because they have higher thermal conductivity, larger volumetric cooling capacity, higher SCP values and better anti-sway performance than simple composite adsorbents. Thermal conductivity of the consolidated composite adsorbent is 6.5–9.8Wm−1 K−1 depending on the molding pressure, ranging from 5 to 15MPa, which is about 32 times higher than the thermal conductivity of CaCl2 powder. The volumetric cooling capacity of consolidated composite adsorbent is about 52% higher than the best result obtained for CaCl2 at the evaporating temperature of −10°C. The SCP of the consolidated adsorbent increases of about 353% than CaCl2 powder from simulation results at T ad=30°C and T ev=−10°C. The consolidated composite adsorbents have good anti-sway performance and they are not easy to be scattered out when the fishing boats sway on the sea. [Copyright &y& Elsevier]