Working Pair Research Articles

Effect of charging operating conditions on open zeolite/water vapor sorption thermal energy storage system

Sorption thermal energy storage (STES) is one of the most promising solutions to realize inter-seasonal thermal energy storage for building heating. However, the analysis of charging operation parameters on the thermal energy storage performance of STES system is insufficient. In this paper, a STES experimental bench using zeolite 4A/water vapor as the sorption working pairs was built, and the charging/discharging experiments were conducted. The thermal energy chain during the full charging-discharging process was analyzed. The experimental results indicated that approximately 60% of the thermal energy provided by the heater was directly lost through the reactor outlet in the charging process, which seriously hindered the improvement of the thermal energy storage performance of the STES system, such as the coefficient of performance (COP). In addition, the influence of charging conditions on the thermal energy storage performance of the system was also investigated. Both the improvement of charging temperature and the reduction of charging air humidity are beneficial to enhancing the thermal energy storage performance of the STES system. When the charging temperature was 150 °C, the energy storage density of zeolite reached a maximum of 251 kWh/m3. The COP of system reduced by 28% when the relative humidity of charging air rose from 20% to 70%. The effect of the volume flow rate of charging air on the thermal energy storage performance of the system is insignificant. The COP of system maintained around 0.212 at different charging air volume flow rates.

Technical-economic-environmental analysis of high temperature cascade heat pump with R718 (high stage) and six different low global warming potential refrigerants (low stage)

High temperature cascade heat pump with two separate refrigerants is a crucial system for decarbonizing industrial heating through electrification. The selection of optimal working refrigerants and temperature lifts relies on not only the thermodynamic analysis outputs such as coefficient of performance but also economic and environmental analyses. In this study, a technical–economic-environmental investigation was conducted for the proposed high-temperature cascade heat pump employing water as the high-stage refrigerant and six low global warming potential refrigerants in the low stage. To facilitate a detailed economic-environmental analysis, precise equipment sizing was undertaken. A comprehensive heat transfer model was developed to size the falling film shell-and-tube cascade heat exchanger, and empirical correlations were employed to size the internal heat exchanger at various cascade temperature lifts. The cascade heat exchanger model is validated against experimental data with less than 5 % error. The distribution of refrigerant charged mass was illustrated using instantaneous density and temperature data. To consolidate all thermal, economic, and environmental sub-indicators into a single parameter, the coefficient of performance, volumetric heating capacity, total annual cost, and total equivalent warming impact were combined as (COP × VHC)/(TAC × TEWI). This proposed comprehensive indicator can be applied to high-temperature cascade heat pumps to identify the optimum working pair and conditions. The results highlighted that R718 + R1234ze(Z) and R718 + R600 were the best working refrigerant pairs, considering all energy, economic, and environmental criteria.

Performance potential and optimal configuration study for low-GWP R161-DMETEG single-stage absorption refrigeration system via pinch technology

New low-GWP R161-DMETEG mixture showed its high feasibility as an alternative working pair to overcome shortcomings of traditional ones. Its internal heat recovery capacity significantly influences operating performances. To systematically explore its ideal performance potentials and heat integration principles of the traditional single-stage absorption refrigeration system (SSARS), this paper conducted the internal heat recovery optimization and derived optimal systems by establishing an approach via pinch technology as a comprehensive planning. The ideal optimal system for maximum heat recovery under different conditions was derived initially using problem tables and Q-T graphical methods. Among all DMETEG-based fluids, R161-DMETEG exhibits the highest average performance potential of approximately 0.677 and an ideal performance improvement of 108%. Subsequently, a new configuration, called MFD-SSARS, was derived using the gird method. Its actual performances and economic feasibility under different parametrical conditions and control strategies were further explored. MFD-SSARS achieves COPs between SSARS and the ideal potential, and it can flexibly adjust internal heat recovery according to varying conditions to stimulate the performance potential. MFD-SSARS maximumly improvs COPs by approximately 65.953% relative to SSARS, reaching 96.167% of its potential under basic conditions. Despite its higher total capital costs than SSARS, it showed the lowest payback period of 2.23 years, thus proving the economic feasibility. Overall, the adopted environment-friendly working pair with designed high-performance configuration of this work serves as a technical solution to overcome current limitations of traditional absorption refrigeration technologies.

Ammonia-based hybrid chemisorption-compression heat pump for high-temperature heating

Conventional compression heat pumps employing natural refrigerant of ammonia can barely meet the requirement of high-temperature heating above 90 °C, while ammonia-based chemisorption heat transformers characterised by high-temperature heating require driving heat source temperature above 80 °C. To address these issues, a novel ammonia-based hybrid chemisorption-compression high-temperature heat pump employing SrCl2-NH3 as the working pair is designed and established in this paper. Particularly, a conventional normal temperature compressor instead of an expensive high-pressure ammonia compressor can be adopted to upgrade the abundant 50–80 °C waste heat to 90–120 °C high-temperature heat. Simultaneously, due to that chemisorption reaction heat is larger than condensing heat of refrigerant, this heat pump has significant potential for improving coefficient of performance (COP). For the first time, regulation strategies of key parameters such as sorption pressure, desorption pressure, and sorption reaction exothermic time are proposed, and these provide the theoretical support for the stable and efficient operation of the heat pump. Moreover, its performance is evaluated by varying operating conditions. The results indicate that at heat output temperature of 100 °C, the optimal sorption pressure and reaction exothermic time are 1.70 MPa and 22 min, respectively. At waste heat temperature of 70 °C and heat output temperature of 110 °C, the COP of the heat pump is 4.58, i.e., its efficiency is 14.5% more than that of R245fa compression one.

Thermochemical energy storage for cabin heating in battery powered electric vehicles

The potential of thermochemical adsorption heat storage technology for battery electric vehicle (EV) cabin heating was explored in this study. A novel modular reactor with multiple adsorption units was designed with working pair SrCl2-NH3. Numerical models of the proposed system were built, and the system was sized to meet the heating requirement for ambient temperatures ranging from −5–10 °C for 1 ∼ 2 h. The simulation results showed the system can satisfy the required supply air temperature by initially activating 6 adsorption units and activating new units once detecting lower air temperature than required. It was found that the final global conversion of adsorption reaction was 0.62–0.67, indicating a relatively stable system performance over ambient temperatures. To supply a heating power of 1.3 kW for 1 h at an ambient temperature of 5 °C, the designed storage system had an adsorbent mass of 16.37 kg in 12 adsorption units. More adsorption units were needed for lower ambient temperatures, such as 23 adsorption units needed to supply a heating power of 2.4 kW at −5 °C ambient condition. It was found that the overall system energy density was 73.8 kWh/m3, whereas the material energy density was 169.4 kWh/m3. This work also demonstrates the importance of considering adsorption dynamics when assessing the performance of an adsorption system and demonstrates the benefits of a modularly designed adsorption reactor for cabin heating.

Bioenergetic Performance of Bali Cows Employed in Ploughing Agricultural Land under Different Work Intensities

The study was undertaken to investigate the use of cow as draught power in soil cultivation of the different type of farming field namely paddy farming field and dry farming field. Ten cows (5 working pairs) were randomly selected from each location so that the total number of obsevation cows was 20 (10 pairs). From each location, 45 breeders were randomly selected as respondents, so that a total of 90 respondents was observed intensively. The results showed, that the main motives recorded from this study are all respondents (100%), both paddy field farmers and dry field farmers, raising cattle for a source of labor and for savings. Most of the farmers raise cattle also for the purpose of being a source of fertilizer (88% of respondents). Cows in dry field farming worked with heigher intensity then those worked on paddy field farming areas. Cows were employed in average 48 days/season and only 4 hours/day, each under 49,60 kg droaugt load, 45 HP draught power, and 45,57 kg draught force, which indicate that the use of cows as a draught animal power in soil cultivation at the transmigration site in the West Nusa Tenggara area is within sub maximal exercise.

Experiment and performance evaluation of an integrated low-temperature proton exchange membrane fuel cell system with an absorption chiller

When the typical operation temperature of the Proton Exchange Membrane Fuel Cell (PEMFC) reaches 333.15–363.15 K, the ratio of electrical energy to waste heat generated by the PEMFC is about 1. In this paper, an absorption chiller with LiBr/[BMIM]Cl/CH3OH as the working pair is proposed to convert the waste heat into cooling capacity. The PEMFC and absorption chiller (AC) systems have been studied from the energy and efficiency point of view. The COP of the integrated system can reach a maximum of 0.85, which is remarkably 0.35 higher than that of the individual PEMFCs. The electrochemical process of the PEMFC and the thermodynamic process of the AC systems are calculated using MATLAB. The results show that the PEMFC operation temperature of 353.15–358.15K is sufficient to drive the AC and meet the requirement of 273.15–283.15K evaporation temperature and 308.15–313.15K condensation temperature. Meanwhile, when the electric power output from the PEMFC is 100 kW, the AC can output approximately 60 kW cooling capacity, which is sufficient to meet the cooling demand of the commercial bus.

Thermodynamic performance analysis of a low-temperature absorption refrigeration system in a proton exchange membrane fuel cell refrigerated vehicle

To utilize the waste heat of a proton exchange membrane fuel cell (PEMFC), an absorption refrigeration system (ARS) with a novel low-temperature working pair LiBr- 1-Butyl-3-methylimidazolium Bromide ([BMIM]Br) /C2H5OH is proposed for cooling in the refrigerated vehicle. The thermodynamic performance of the ARS using LiBr-[BMIM]Br/C2H5OH is investigated under various operating conditions and compared with that using the conventional working pair LiBr/H2O. The efficiency performance of the PEMFC refrigerated vehicle using ARS and vapor compression refrigeration system (VCRS) are also studied and compared under different operating conditions. The results show that the ARS achieves the maximum coefficient of performance (COP) of 0.86 and the generation temperature is reduced to 65.45 °C with LiBr-[BMIM]Br/C2H5OH a decrease around 15% in comparison to LiBr/H2O. Comprehensive efficiency of the stack coupled with ARS is up to 85% due to recovery its waste heat. Under identical output power and cooling capacity of the refrigerator vehicle, the stack coupled with a VCRS has a comprehensive efficiency of 70% and requires a larger power scale. Thus, the stack coupled with ARS using LiBr-[BMIM]Br/C2H5OH has a great significance for enhancing the performance, enlarging the mileage, and reducing the cost of the refrigerator vehicle.

Cooling performance of compression-absorption cascade system with novel ternary ionic-liquid working pair

The compression-absorption cascade system (CACS) is an efficient way to use waste heat or renewable energy. However, most of the current studies are all based on heating scenarios, and the cooling characteristics of CACS have not been reported. In terms of absorption working pairs, ionic liquids (ILs) have great potential to become alternative working fluids for absorption systems, but one of the factors restricting the large-scale application is their high price. Seeking effective strategies to reduce economic constraints while ensuring the excellent performance of IL working pairs will become a hot topic in the future. In order to overcome the application limit of ILs, a feasible strategy is proposed which the relatively cheap salt is used to replace part of the expensive IL and they are employed together as the absorbent. In this work, the vapor-liquid equilibrium data of novel IL working fluid LiBr/[EMIM][OAC]/H2O is measured experimentally, and the cooling performance of CACS with the proposed working pair is analyzed. The results show that the cooling efficiency of CACS is 0.738–0.849, which is commonly higher than traditional absorption chillers. As for comparing with reference working fluids, the novel working pair can improve the maximum performance by 1.80%–46.81%. In addition, the crystallization problem can be overcome to some extent compared with LiBr/H2O under the same absorption ability, and as for comparing with [EMIM][OAC]/H2O, the economic limitation can be alleviated. This work can be used to ease the economic limit of ILs due to the immature market right now, and give a reference for seeking a satisfactory cooling method of buildings in the context of carbon neutrality.

Investigation of the cascade type of hybrid adsorption-vapor compression chiller

A numerical analysis was performed on a hybrid cooling system consisting of an adsorption chiller (ADC) and a vapor compression chiller (VCC) operating in a cascade mode. The system was evaluated for its overall performance and energy savings compared to standalone ADC or VCC cooling systems. The ADC utilizes an RD silica gel/water working pair, while the VCC uses R410A refrigerant. The cooling strategy involves the ADC providing cooling for loads up to 10 kW, with the VCC supporting the ADC when cooling loads exceed 10 kW, up to 15 kW. MATLAB and Refprop were used to model the system, and the results were consistent with prior research. The study examined the effects of adsorption cycle time, hot water temperature, cold water temperature, adsorbent particle size, and intermediate mass flow rate. Additionally, the performance of different adsorbents, including CaCl2 bound to mesoporous silica (SWS-1L) and Ferro-aluminophosphate (FAM-Z01), was compared to RD silica gel. The hybrid system reduced compressor work by 94.57% and 97.69% compared to conventional VCC when the hot water temperature was set to 90 °C, and cold water temperature was set to 26 °C, respectively. The hybrid system achieved the highest energy savings and overall coefficient of performance, with SWS-1L achieving a 91.37% energy savings and a 6.71 coefficient of performance. Therefore, the cascade-type hybrid cooling system is a superior alternative, particularly for cooling loads ranging from 10 kW to 23 kW, offering significant energy savings compared to conventional VCC systems.

Using nanoparticles for performance enhancement of a solar energy-driven power/hydrogen cogeneration plant based on thermochemical cycles: Multi-aspect analysis and environmental assessment

A cogeneration of power and hydrogen plant driven by clean solar energy is developed, analyzed and optimized in this paper. For hydrogen production in the suggested plant, a thermochemical cycle with Vanadium–Chlorine (VCl) working pair is integrated with parabolic trough collectors and an auxiliary heater to provide the required temperature level. For power generation, however, an organic Rankine cycle is applied to generate electricity from extra heat which is not utilized in VCl thermochemical cycle. For performance improvement of developed cogeneration framework, nanoparticles are applied for enhancing thermal behavior of collector field. A comprehensive analysis is conducted to determine system performance enhancement with nanufluid as compared to basefluid case in thermal loop of collectors. Thermodynamic investigations paying more attention on exergy evaluations are carried out along with economic considerations to assess system performance. Furthermore, to address the proposed plant's environmental impacts, the overall plant's performance and carbon dioxide emission reduction are estimated. Parametric appraisal is implemented to specify operating factor impacts on power and hydrogen production and unit cost of product. Also, multi-objective optimization is performed based on cost and efficiency indices. It is found that, addition of nanoparticles to basefluid can enhance system performance roughly by 3−5%. The nanofluid based framework attains efficiency of 40.16% and unit product cost of 39.93 $/GJ under optimum conditions. Finally, based on the findings of the environmental impact analysis, the designed system in cogeneration mode was able to mitigate CO2 emissions by 1173 kg/h.

Vapor-liquid equilibrium for dimethyl ether and three imidazolium ionic liquids as working pairs in absorption-refrigeration cycle

To overcome the shortcomings of traditional working pairs of H2O/LiBr and NH3/H2O, the combination of dimethyl ether (DME) and ionic liquids (ILs) have been studied recently. The solubilities of DME in [HMIM][BF4], [HMIM][PF6] and [HMIM][Tf2N] were firstly measured and correlated using NRTL equation. The thermodynamic performance of absorption refrigeration system (ARS) using those working pairs are compared with R152a/[HMIM][Tf2N], R1234ze(E)/[HMIM][Tf2N] and other DME/IL pairs which include [BMIM][BF4], [BMIM][PF6] and [BMIM][Tf2N]. Under the studied condition Tg/Ta/Tc/Te = 325–370 K/300 K/300 K/278 K, the maximum COPs of DME/[HMIM][Tf2N], DME/[BMIM][PF6] and R152a/[HMIM][Tf2N] in ARS are 0.592, 0.531 and 0.648, respectively, while that of R1234ze(E)/[HMIM][Tf2N] is only 0.345. DME/[BMIM][PF6] performs best at Tg = 350 K, but at Tg = 340 K, DME/[HMIM][Tf2N] shows better performance. The difference of optimal Tg between them is about 10 K. It shows that ARS of using DME/[HMIM][Tf2N] can utilize lower-grade waste heat. Our studies prove that DME/ILs are good choices to balance the environmental protection property and energy efficiency improve.

Modified Silicon Anode for Improved Low-Temperature Performance of Lithium-Ion Batteries

Abstract The shift away from fossil fuels for modern-day energy requirements has resulted in a higher demand for electric vehicles and has led to a critical role for lithium-ion batteries. Next-generation higher capacity electrode materials are needed to meet the demands of future electric vehicles. Lithium-ion batteries function optimally around room temperature (23 °C), but discharge capacity diminishes rapidly below 0 °C and significantly affects the population living in colder climates. Higher capacity electrode materials such as silicon need to be paired with new electrolytes that favor ideal low-temperature performance. This work pairs a typical nickel-rich lithium cathode with a modified silicon anode and a ternary carbonate/ester electrolyte to demonstrate improved discharge capacity at subzero temperature.

Amine-based thermal energy storage system towards industrial application

Thermal energy storage (TES) bridges the intermittence of renewable energy to generate steady and efficient clean energy. While amine-based CO2 capture is a leading technology for CO2 emission reduction, we innovatively employed the amine technology for long-term thermal energy storage, namely amine-based TES (ATES). The system utilises the thermally reversible amine-CO2 reaction as the energy storage working pair, where low-grade thermal energy is used to break the amine-CO2 chemical bond with the heat stored and released via exothermic amine-CO2 reaction to produce high-quality thermal energy when required. Using benchmark absorbent monoethanolamine (MEA), we simulate and optimize the ATES system, and demonstrate that ATES exhibits desirable thermal energy storage performance with high-quality heat output up to 131 °C, high thermal energy conversion efficiency of >70%, moderate energy density of 210 kJ/kg and long-term storage, which outperforms the water-based sensible thermal storage technology. More importantly, the ATES is built on commercially viable amine process and heat exchange system, indicating its great potential for commercial applications, such as space heating and industrial waste heat storage.

Integrated heat and cold storage enabled by high-energy-density sorption thermal battery based on zeolite/MgCl2 composite sorbent

Thermal energy storage (TES) plays a critical role in renewable energy utilization, waste heat recovery, and heating/cooling applications. However, low energy density is a long-standing challenge for conventional TES systems based on sensible heat and latent heat methods, and thus impedes the widespread deployment of heat storage and cold storage. Herein, a novel high-power/energy-density sorption thermal battery (STB) is developed for realizing integrated heat and cold storage by using zeolite 13X-based composite sorbent-water working pair. The zeolite 13X is firstly treated with MgCl2 salt to improve water uptake and regulate sorption equilibrium characteristics. The results demonstrate that the energy density of zeolite 13X/MgCl2 can be improved by 15.1% when compared to zeolite 13X. The STB exhibits the distinct capability of realizing high-power/energy-density heat storage and cold storage, and the working temperature can be changed according to different demands. The average power densities for heat storage and cold storage are 279.66 W/kg and 242.95 W/kg, respectively. Meanwhile, the average energy densities for heat storage and cold storage are as high as 686.86 kJ/kg and 597.13 kJ/kg, respectively, superior to the current sensible/latent heat energy storage. The proposed zeolite/MgCl2-based sorption thermal battery offers a promising route to realize high-density heat storage and cold storage simultaneously based one thermal energy storage device.

Enhanced Water Adsorption of MIL-101(Cr) by Metal-Organic Polyhedral Encapsulation for Adsorption Cooling

Metal-organic frameworks (MOFs) are one of the most promising adsorbents in the adsorption cooling system (ACS) for their outstanding water adsorption performance. Notwithstanding that fact, numerous reports pay more attention to the ACS performance improvement through enhancing equilibrium water uptake of MOFs. However, adsorption cooling performance, including specific cooling power (SCP) and coefficient of performance for cooling (COPC) of MOF/water working pairs, always depends on the water adsorption kinetics of MOFs in ACS. In this work, to increase the water adsorption rate, the preparation of MOP/MIL-101(Cr) was achieved by encapsulating hydrophilic metal-organic polyhedral (MOP) into MIL-101(Cr). It was found that the hydrophilicity of MOP/MIL-101(Cr) was enhanced upon hydrophilic MOP3 encapsulation, resulting in a remarkable improvement in water adsorption rates. Furthermore, both SCP and COPC for MOP/MIL-101(Cr)-water working pairs were also improved because of the fast water adsorption of MOP/MIL-101(Cr). In brief, an effective approach to enhance the water adsorption rate and cooling performance of MOF-water working pairs through enhancing the hydrophilicity of MOFs by encapsulating MOP into MOFs was reported in this work, which provides a new strategy for broadening the application of MOF composites in ACS.

How to rationally screen refrigerant/ionic liquids for thermal cooling: A multi-criteria approach based on machine learning

Absorption heat pumps (AHPs) for thermal cooling show great potential in utilizing renewable and waste heat towards carbon neutrality. AHPs using ionic liquids (ILs) as absorbents have attracted considerable attention for avoiding the shortcomings of traditional working fluids. To develop absorption technologies with high efficiency, compactness, and flexibility, a multi-criteria approach coupling the property models based on machine learning and UNIFAC methods, cycle models, and heat exchanger models is proposed to screen the optimum refrigerant/ILs. In terms of cycle performance, heat transfer performance, hydraulic resistance, and applicable range, the comprehensive performance of 214 novel refrigerant/ILs is estimated to identify suitable candidates. Six indicators are selected to compare the working pairs comprehensively: H2O/[OMIM][OAc] performs the best in terms of coefficient of performance (0.815), pumping power (0.071 W), and supply-side applicable operating ratio (76.8%), while NH3/[DBIM][Tf2N] yields the lowest saturation temperature drop (0.157 K) and the highest demand-side applicable operating ratio (64.9%). Within the studied IL-based working fluids, NH3/[DBIM][Tf2N] in the generator exhibits the highest heat transfer coefficient of 0.476 kW/(m2·K). Considering the trade-off between heat transfer performance and hydraulic resistance, satisfactory solution velocities are recommended for different working fluids with a saturation temperature drop limit of 2.2 °C. Based on the Pareto optimization, H2O/[OMIM][OAc] is highly recommended for industrial applications because of its crystallization-free nature, high COP, and compact system size. The proposed multi-criteria approach achieves large-scale screening of optimum ILs for highly efficient, compact, and flexible thermal cooling.

Crystallization Temperature, Vapor Pressure, Density, Viscosity, Specific Heat Capacity, and Corrosivity of the LiNO3-DEG/H2O Ternary System

As a novel working pair to replace CaCl2/H2O and LiNO3/H2O for open absorption heat pumps, LiNO3-DEG/H2O with a mass ratio of 1:4 was further researched on the basis of the overall assessment of the vapor pressure and crystallization temperature. The crystallization temperature, vapor pressure, density, viscosity, and specific heat capacity of the working pair were measured with mass fractions from 0.70 to 0.90. The vapor pressure, density, viscosity, and specific heat capacity were measured from 293.15 to 373.15 K. Regression equations for the experimental values were obtained by a least-squares method. The results showed that the vapor pressures of LiNO3-DEG/H2O with a mass fraction of 0.80 were very close to that of LiNO3/H2O with a mass fraction of 0.50, and the vapor pressures of LiNO3-DEG/H2O with a mass fraction of 0.85 were also very close to that of CaCl2/H2O with a mass fraction of 0.45. Crystallization temperatures of LiNO3-DEG/H2O with a mass fraction from 0.70 to 0.90 were lower than 243 K. Corrosion weight loss values of carbon steel, stainless steel, and copper in an atmosphere of air for LiNO3-DEG/H2O were 1.17 × 10–4, 0.35 × 10–4, and 0.33 × 10–4 g/(cm–2·m–1), respectively, which were much smaller than those for LiNO3/H2O and CaCl2/H2O.

High energy-density and power-density cold storage enabled by sorption thermal battery based on liquid-gas phase change process

Cold storage is essential for the preservation of food/medical goods, energy-saving of air conditioning, and emergency cooling. However, conventional cold storage in the form of sensible heat or solid-liquid latent heat suffers from the low energy density and large cold loss during long-term storage. To address the problem, a scalable sorption thermal battery (STB) with storage capacity of 30 kWh is designed and fabricated for realizing high energy-density and power-density cold storage by proposing sorption-induced liquid-gas phase change strategy. The STB utilizes the bonding energy of sorption working pair of zeolite 13X-water to achieve cold storage during charging phase, and utilizes the liquid-gas evaporation heat of water to realize cold production during discharging phase. The cold-storage performance of the STB prototype during charging/discharging processes is experimentally investigated at different operating conditions. By optimizing the assembled structure of solid-gas reactor and enhancing the heat transfer performance of liquid-gas evaporator, the STB exhibits high cold energy density up to 114.92 Wh/kg and 26.76 kWh/m3, and high power density of 455.62 W/kg and 106.10 kW/m3, over the conventional cold storage technologies. Correspondingly, the STB demonstrates a good performance in thermal management of data centers with cooling power as high as 150 kW. Moreover, the STB has the distinct advantage of near-zero cold energy loss in long-term cold storage. The proposed scalable sorption thermal battery based on sorption-induced liquid-gas evaporation heat of liquid offers a promising route to realize high energy density cold storage.

Adsorption Capacities of Ammonia‐Activated Carbon Pairs in a Single‐Bed Adsorption Cooling System

AbstractIn this study, the adsorption capacities of activated charcoal‐ammonia working pairs at room temperature, at which waste heat is supplied, were studied in a tube‐in‐tube adsorption bed in the pressure range of 0.4–10 bar. A double‐pipe adsorption bed was designed, constructed, and utilized for sequential adsorption and desorption of ammonia at 27 °C. Three types of granular activated carbons (GACs) with different particle size distributions were used as adsorbents. Experimental observations showed that the highest adsorption capacity for ammonia was shown by GAC‐2 with broader particle size distribution. The adsorption behaviors of all three adsorbents closely followed the Langmuir model under the operating conditions used in the study.