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Sorption devices are important tools for the efficient utilization of fuels and waste heat. Amid a tremendous diversity of cycles and applications, all sorption systems have an equilibrium vapor pressure that depends on the sorbent temperature and composition. The vapor pressure properties of working fluids are reported in the literature in a variety of ways, which impedes wide-ranging cross comparisons or screening studies for novel applications. This work compiles equilibrium vapor pressure properties for 123 liquid absorbents with 31 absorbates and 139 solid adsorbents with 16 adsorbates. The adsorption pairs are represented with six functional forms. Most of the absorption pairs are represented with 10 functional forms, plus several that are represented with custom empirical equations. Because the functional forms used in the literature vary widely, in this work each functional form was generalized. This paper is designed to facilitate comparisons of working fluid properties for screening studies, provide a quick reference to existing research, and present a framework for standardizing the reportage of vapor pressure equilibrium data for existing and future working pairs.

The present work aims at the thermodynamic analysis of different working pairs in adsorption heat transformers (AdHT) for low-temperature waste heat upgrade in industrial processes. Two different AdHT configurations have been simulated, namely with and without heat recovery between the adsorbent beds. Ten working pairs, employing different adsorbent materials and four different refrigerants, have been compared at varying working boundary conditions. The effects of heat recovery and the presence of a temperature gradient for heat transfer between sinks/sources and the AdHT components have been analyzed. The achieved results demonstrate the possibility of increasing the overall performance when internal heat recovery is implemented. They also highlight the relevant role played by the existing temperature gradient between heat transfer fluids and components, that strongly affect the real operating cycle of the AdHT and thus its expected performance. Both extremely low, i.e., 40–50 °C, and low (i.e., 80 °C) waste heat source temperatures were investigated at variable ambient temperatures, evaluating the achievable COP and specific energy. The main results demonstrate that optimal performance can be achieved when 40–50 K of temperature difference between waste heat source and ambient temperature are guaranteed. Furthermore, composite sorbents demonstrated to be the most promising adsorbent materials for this application, given their high sorption capacity compared to pure adsorbents, which is reflected in much higher achievable specific energy.

The D3.3 reports the design efforts, experimental tests and optimization activities carried out on the hybrid chiller produced by FAHR. These activities are the core aims of T3.2 "Adsorption HP upgrade and guidelines for installation/combination with other H&C technologies" whose task leader is FAHR. The connected activities related to the guidelines for the hybrid chiller installation were already carried out and are fully explained in D3.4. FAHR was in charge to design and manufacture the hybrid chiller, ITAE lead the experimental test activities obtaining the full performance characterization of this technology and an optimization of the control strategy. FAHR designed a hybrid chiller composed by a sorption unit and a compression one connected in parallel to the on the load side (cold side) and in series connection to the heat sink (heat rejection side). The adsorption and compression heat pumps operate in parallel to each other supplying cold water to one common cold consumer. The adsorption chiller covers the base load, while the compression chiller is activated only if the required parameter cannot be achieved by the adsorption unit alone. Initially, a cascade layout was considered as the best solution for the SunHorizon project design. However, during the engineering works and tests it has been noted, that considering its specific advantages and drawbacks, the parallel layout is the most beneficial for the intended application. Several innovations were introduced in this technology, they regard the adsorber's coating, the heat exchangers and the process modules, more details about these aspects are explained in D3.11. A further innovation introduced, thanks to the experimental tests and ITAE support, is the optimization of the control strategy that will let to improve the efficiency and reliability of the hybrid chiller For the experimental tests, the hybrid chiller was shipped to the CNR-ITAE labs in Messina, an intense experimental campaign was planned with the aim to produce a full performance map of the tested technology and deeply investigate on its optimisation. During the tests several troubles with the control settings were founded and solved through the continuous exchange of information between FAHR and ITAE. Finally, a novel design of control strategy was suggested by ITAE and implemented by FAHR, thus achieving a global improvement of reliability and efficiency of the hybrid chiller. The results of the tests let also to produce the performance map of the chiller and a mathematical correlation, based on statistical regression, that let to easily calculate the performance by a polynomial expression. This last finding is useful for the modelling of the hybrid chiller and its implementation on simulations and AI interfaces. In conclusion, the experimental characterization showed that the hybrid configuration lets to achieve a lower improvement, in terms of performance, if compared with a compression chiller than the expected one. This was mainly related to the design of MT circuits and to the controls. The new control strategy will let to increase the efficiency and the reliability of the system, thus making the hybrid chiller more competitive of a compression one, in terms of cooling power and EER.

In this study, the development and comparative characterization of different composite sorbents for thermal energy storage applications is reported. Two different applications were targeted, namely, low-temperature space heating (SH) and domestic hot water (DHW) provision. From a literature analysis, the most promising hygroscopic salts were selected for these conditions, being LiCl for SH and LiBr for DHW. Furthermore, two mesoporous silica gel matrixes and a macroporous vermiculite were acquired to prepare the composites. A complete characterization was performed by investigating the porous structure of the composites before and after impregnation, through N2 physisorption, as well as checking the phase composition of the composites at different temperatures through X-ray powder diffraction (XRD) analysis. Furthermore, sorption equilibrium curves were measured in water vapor atmosphere to evaluate the adsorption capacity of the samples and a detailed calorimetric analysis was carried out to evaluate the reaction evolution under real operating conditions as well as the sorption heat of each sample. The results demonstrated a slower reaction kinetic in the vermiculite-based composites, due to the larger size of salt grains embedded in the pores, while promising volumetric storage densities of 0.7 GJ/m3 and 0.4 GJ/m3 in silica gel-based composites were achieved for SH and DHW applications, respectively.

Sorption devices are important tools for the efficient utilization of fuels and waste heat. Amid a tremendous diversity of cycles and applications, all sorption systems have an equilibrium vapor pressure that depends on the sorbent temperature and composition. The vapor pressure properties of working fluids are reported in the literature in a variety of ways, which impedes wide-ranging cross comparisons or screening studies for novel applications. This work compiles equilibrium vapor pressure properties for 123 liquid absorbents with 31 absorbates and 139 solid adsorbents with 16 adsorbates. The adsorption pairs are represented with six functional forms. Most of the absorption pairs are represented with 10 functional forms, plus several that are represented with custom empirical equations. Because the functional forms used in the literature vary widely, in this work each functional form was generalized. This paper is designed to facilitate comparisons of working fluid properties for screening studies, provide a quick reference to existing research, and present a framework for standardizing the reportage of vapor pressure equilibrium data for existing and future working pairs.

Adsorption desalination (AD) is an emerging technology to reduce risk of freshwater scarcity, able to use renewable energy and applicable in decentralized areas. Only limited sorbents have been tested experimentally for AD systems. This study developed two composite sorbents based on LiCl as embedded salt and two matrices, namely, silica gel (LiCl@SG_30) and expanded vermiculite (LiCl@EVM_45). The performed analysis figured out how the trade-off between high sorption capacity and good mass transfer caused by their different pore structures influences the desalination operations. The results were compared against a standard microporous Siogel. The sorption isobars indicated that the sorption behavior of LiCl@SG_30 is the combination of silica gel and the embedded LiCl crystals, while for LiCl@EVM_45 is mainly the sorption process of the embedded LiCl crystals. LiCl@EVM_45 reached the highest sorption capacity. The Dubinin-Astakhov equation described the equilibrium capacities of the sorbents. The kinetics coefficient (k) was employed to evaluate the sorption rate. Microporous Siogel showed the highest sorption rate, followed by LiCl@SG_30 and LiCl@EVM_45. Finally, predicted specific daily water production (SDWP) were calculated, showing promising features for both LiCl@SG_30 and LiCl@EVM_45, with LiCl@SG_30 achieving SDWP ranging from 43 to 60 m3/tonne/day) for the selected conditions.

The thermal masses of components influence the performance of many adsorption heat pump systems. However, typically when experimental adsorption systems are reported, data on thermal mass are missing or incomplete. This work provides original measurements of the thermal masses for experimental sorption heat exchanger hardware. Much of this hardware was previously reported in the literature, but without detailed thermal mass data. The data reported in this work are the first values reported in the literature to thoroughly account for all thermal masses, including heat transfer fluid. The impact of thermal mass on system performance is also discussed, with detailed calculation left for future work. The degree to which heat transfer fluid contributes to overall effective thermal mass is also discussed, with detailed calculation left for future work. This work provides a framework for future reporting of experimental thermal masses. The utilization of this framework will enrich the data available for model validation and provide a more thorough accounting of adsorption heat pumps.

The present work reports the experimental evaluation of the performance of a cascade chiller, having an adsorption cycle as topping cycle and a vapour compression cycle as bottoming cycle. An experimental testing campaign was carried out at CNR ITAE, focused on the definition of performance maps of the system under different operating conditions. In particular, heat source temperatures between 70°C and 85°C were evaluated, cooling temperatures between 22°C and 40°C and chilled water temperatures of -12°C up to 5°C, in order to reproduce the operation in different seasons, climates and user requests (i.e. air conditioning and refrigeration). Cooling powers from 18 kW (under air conditioning conditions) from 12 kW (for refrigeration conditions) were obtained for the lower cooling temperatures. Indeed, the cooling temperature has a great influence on the cooling capacity of the system, whereas heat source temperature has a smaller effect on the capacity of the system. Finally, the energy savings that can arise from such a configuration were calculated and up to 25% reduction, if compared to a standard vapour compression system can be achieved. A reduction in CO2 emissions up to 3.5 yearly tons were calculated as well

In this study, the development and characterization of composite sorbents based on commercial mesoporous silica gels and LiCI for seasonal thermal energy storage (STES) applications is described. The reported activity aims at validating the operation of sorption STES in various cold climatic zones in Europe. Accordingly, the reference boundary conditions were identified by means of a climatic analysis in two climatic zones, namely, Central and Northern Europe. The acquired mesoporous silica gels were characterized, to evaluate the textural properties, i.e. specific pore volume and pore size, needed to define the optimal salt solution compositions to maximize the amount of salt embedded. The synthesized samples were firstly investigated using scanning electron microscopy and nitrogen physisorption that demonstrate the presence of a small quantity of salt over the external surface rather than inside the pores. A hydrothermal treatment, based on slow adsorption followed by a slow desorption step, was defined to solve this issue. Finally, starting from the measured equilibrium isobars, the expected STES density at material level was evaluated, obtaining values as high as 1080 J/g under cold Northern European climatic condition, corresponding to 650 MJ/m(3). (C) 2020 The Authors. Published by Elsevier Ltd.

This article evaluates the hydrothermal and mechanical stability of an adsorbent composite foam based on zeolite silicone for application in adsorption heat pump. The adsorption properties of the fresh composite adsorbents and their morphological features were already presented in previous papers. In the present work, hydrothermal aging of composite foams, at varying SAPO-34 zeolite contents and under real operating conditions, was carried out in order to verify the stability of the synthetized material. This improvement of knowledge is a key point for the industrial application. This evaluation was successfully performed by means of adsorption measurements and compression test on aged samples, up to 1500 aging cycles. The adsorption properties of composite foams are effective and stable up to the maximum number of cycles of the aging process. Instead, from the mechanical point of view, composite foams with high content of zeolite, aged at long cycles, evidenced a slight stiffening that stimulates mechanical brittle behavior. The composite foam with 67% zeolite filler represents a threshold value beyond which the action of the hydrothermal aging implies a significant loss of flexibility and mechanical integrity, which limits its applicability under typical conditions.

This paper presents the experimental characterisation of three zeotype materials, namely, AlPO-18, FAPO-34 and SAPO-34, suitable for adsorption heat transformation applications, employing water as refrigerant. Morphological and thermo-physical analyses were performed on each sample. In particular, the adsorption capacity of each material was evaluated by measuring a complete set of water vapour adsorption/desorption isotherms, in order to investigate the hysteresis effect. The obtained equilibrium data were fitted by means of Dubinin-Astakhov equation, both for adsorption and desorption branches. Finally, a thermodynamic analysis of the achievable performance of these three working pairs was performed under three main operating conditions, namely, thermal energy storage, air conditioning and heat pumping. The achieved results confirmed the potentiality of these adsorbents, showing promising cooling and thermal COP, up to 0.80 and 1.60 respectively, and heat storage capacities both for daily and seasonal operation.

This paper reports about the combined experimental and numerical investigation of a novel small size multi-generation system, for electric (i.e.

The aim of this paper is to study the equilibrium and dynamics of water adsorption on a commercial silica gel Siogel. This adsorbent has recently been suggested and tested for adsorptive transformation and storage of low temperature heat. The original data on the water vapour equilibrium and dynamics are compared with those earlier reported for the Fuji silica RD. This database can be used for theoretical analysis, mathematical modeling and evaluation of adsorptive cycles based on the working pair “water – Siogel” and driven by heat from renewable heat sources.

Adsorption storage is considered a promising alternatives both in industrial and residential applications. One of limiting factors for the application in buildings is the need for compact and efficient systems, with high energy density. To this aim, the realization of porous structures (e.g. metal or polymeric foams) for zeolite synthesis or embedding has to be evaluated. Different metal foams, realized in AlSi7 alloy with different pore densities and thicknesses were realized and experimentally tested in order to define the most suitable ones for heat storage applications. At first, morphology characterization of the materials through an optical microscope was carried out. Subsequently, heat transfer capacity was evaluated by means of a self-developed apparatus at CNR-ITAE, which makes use of Peltier cells for cycling the foam samples, while the temperatures in different part of the foams is measured. By means of cycles with different amplitudes and length, the effect of pore size and thickness of the sample was evaluated. Dynamic characterization of the coated foams was carried out by means of a gravimetric Large Temperature Jump apparatus at CNR-ITAE. Finally, a numeral model was realized in COMSOL Multiphysics and validated against experimental results, that was subsequently used to define an "equivalent" material that can be used for dynamic simulation of a complete adsorption storage system.

Hybrid sorption-compression systems are gaining interest for heating/cooling/ refrigeration purposes in different applications, since they allow exploiting the benefits of both technologies and a better utilization of renewable sources. However, design of such components is still difficult, due to the intrinsic complexity of the systems and the lack of reliable models. In particular, the combination of adsorption-compression cascade unit has not been widely explored yet and there are no simulations or sizing tools reported in the literature. In this context, the present paper describes a model of a hybrid adsorption-compression system, realised in Modelica language using the commercial software Dymola. The models of the main components of the sorption and vapour compression unit are described in details and their validation presented. In addition, the integrated model is used for proving the feasibility of the system under dynamic realistic conditions and an example of the technical sizing that the model is able to accomplish is given.

Deliverable del progetto SWS Heating relativo alla selezione dei KPIs tecnico economici per la valutazione delle performance del sistema e dei componenti utilizzati

SAPO-34 – a silicoaluminophosphate microporous material – has recently attracted a great attention in the field of sorption thermal storage, since it is characterized by good water adsorption behavior (i.e. type V adsorption isotherms) and low regeneration temperature (i.e. 80 °C, for instance available by standard solar thermal energy collectors). However, the nanoscale mechanisms of water transport and adsorption in the microporous framework of SAPO-34 cannot be fully unveiled by experiments alone. In this work, water adsorption onto SAPO-34 is for the first time studied by means of an atomistic model built upon experimental evidence. First, Monte Carlo simulations are employed to set up a convenient atomistic model of water/SAPO-34 interactions, and numerical adsorption isotherms are validated against experimental measures. Second, the validated model is used to study the water diffusion through SAPO-34 by molecular dynamics simulations, and to visualize preferential adsorption sites with atomistic detail. Such atomistic model validated against experiments may ease the investigation and in silico discovery of silicoaluminophosphates for thermal storage applications with tailored adsorption characteristics.

The present book focuses on the experimental methods for the characterisation of innovative thermal energy storage (TES) technologies, comprising high temperature sensible TES, latent TES and thermochemical TES. It provides useful information about the currently employed characterisation methods at lab level, starting from the material up to the systems, trying to elucidate the development level reached by each investigated technology

Recently, a new composite “LiCl inside Multi-Wall Carbon NanoTubes” (LiCl/MWCNT) has been suggested as water sorbent for Adsorption Thermal Energy Storage (ATES), because it has a large thermal storage capacity of 1.7 kJ/g for a daily heat storage cycle. This work addresses the results of the study of water sorption dynamics on the novel composite loaded into representative small scale fragments of a common finned flat-tube HEx. The study consists of four parts: (1) shaping the LiCl/MWCNT composite as grains using polyvinyl alcohol (PVA) as a binder; (2) analysis of sorption equilibrium for the pair “LiCl/ MWCNT/PVA – water”; (3) measuring the thermal storage capacity of the granulated LiCl/ MWCNT/PVA composite; (4) investigation of water sorption dynamics on the LiCl/MWCNT/PVA under typical conditions of the daily storage cycle. It is shown that the thermal storage capacity of the LiCl/MWCNT/PVA composite equals 1.5–1.6 kJ/g. The specific power reaches 4.2 and 9.8 kW/kg of the heat release and thermal storage stages, respectively. The results obtained show that the working pair “LiCl/MWCNT/PVA – water” appears to be advantageous for ATES.

In the present paper design, realization and testing of a novel small scale adsorption refrigerator prototype based on activated carbon/ethanol working pair is described. Firstly, experimental activity has been carried out for identification of the best performing activated carbon available on the market, through the evaluation of the achievable thermodynamic performance both under air conditioning and refrigeration conditions. Once identified the best performing activated carbon, the design of the adsorber was developed by experimental dynamic performance analysis, carried out by means of the Gravimetric-Large Temperature Jump (G-LTJ) apparatus available at CNR ITAE lab. Finally, the whole 0.5 kW refrigerator prototype was designed and built. First experimental results both under reference air conditioning and refrigeration cycles have been reported, to check the achievable performance. High Specific Cooling Powers (SCPs), 95 W/kg and 50 W/kg, for air conditioning and refrigeration respectively, were obtained, while the COP ranged between 0.09 and 0.11, thus showing an improvement of the current state of the art.

Adsorption heat pumps and chillers provide sustainable heating and cooling by transforming waste or solar heat. To increase the efficiency of adsorption heat pumps and chillers, new adsorber designs are constantly proposed. However, evaluating the efficiency of new adsorber designs is a time- and money consuming task. To reduce time and costs, we combine two methods in this work: First, the kinetic performance is evaluated experimentally using the Large Temperature Jump method for a representative adsorber part. Second, a dynamic model for the adsorber is developed and validated. The validated adsorber model is used in a dynamic model of a complete adsorption heat pump cycle. Our approach allows for a sound analysis of novel adsorber designs by determination of the efficiency indicators specific cooling power (SCP) and coefficient of performance (COP) based on a representative adsorber part. We studied a representative adsorber part made from an extruded aluminum tube heat exchanger filled with silica gel 123. We determined SCP and COP as function of adsorption and desorption times and found a maximum SCP 268 W kg(-1) with a corresponding COP of 0.51 for a desorption time of 125 s and an adsorption time of 200 s. (C) 2015 Elsevier Ltd. All rights reserved.

This paper reports an experimental study aimed to elucidate the effect of non-adsorbable gases (air and hydrogen) on dynamics of isobaric adsorption stage of an adsorptive chiller (AC) cycle. This is the first study performed on real small scale adsorbers, based on commercial heat exchangers (HExs) filled with loose grains of the adsorbent AQSOA (TM)-FAM-Z02. The adsorption dynamics was studied by a gravimetric large temperature jump method under conditions of typical AC cycle. Three notable observations are described in the paper: (1) at any gas pressure P-gas, the experimental uptake curves are exponential; (2) the adsorption rate is extremely sensitive to traces of residual air and depends on the HEx geometry and the nature of residual gas; (3) the effect of hydrogen is less dramatic as compared with air. The minimal amount of residual air necessary to form the blocking air-rich layer is evaluated by developing a one-dimensional stationary model of the vapour adsorption in the presence of gas. This amount is found to be highly sensitive to the total vapour pressure and the HEx mass transfer surface area. Practical recommendations on avoiding/dumping the effect of residual gas are made. (C) 2016 Elsevier Ltd. All rights reserved.

The integration of sorption systems on-board fishing vessels has been explored in the last decade, but the limitations in power density and temperature levels achievable have hindered their application. In the present paper, the integration of hybrid sorption–compression systems was evaluated. Different shipping vessels and routes in seas and oceans were considered in the analysis, with engine powers from 190 kW to 500 kW. The feasibility of series and cascade configurations was studied and the possible benefits, in terms of fuel and CO2 savings, were evaluated. The analysis, which also considered the payload due to the extra fuel needed to transport the equipment for refrigeration, showed that up to 75% savings can be obtained, with CO2 emissions avoided up to 20 t/y., peer-reviewed

Analysis of the Ad-HEx dynamic behaviour is of pivotal importance in development of advanced adsorber concepts, enabling reduction of weight and volume of the real adsorption heat pump/chiller unit, as well as its energy density enhancement.

Thermally-driven sorption systems can utilize a wide range of heat source to provide heating, cooling, heat transforming, and energy storage. The performance of a sorption system strongly depends on the equilibrium vapor pressure of the sorbate, which can be calculated using an equilibrium equation of state for the working pair. Numerous studies have been published formulating the vapor equilibrium from experimental measurements for various sorption working pairs. However, each study typically includes only a few working pairs, and information is scattered across a large number of sources. Therefore, it takes considerable effort to pinpoint the correlation for a desired working pair. Moreover, variations of functional forms, terminologies, and conventions were found across different literatures, adding to the difficulty of implementing multiple correlations for computer simulation and comparison. To overcome these challenges, this study created a readily usable database of vapor equilibrium for both absorption and adsorption working pairs with easy indexing and convenient implementation for computer simulation. The database was constructed by generalizing the equilibrium equations of state to provide compatibility with data from various published sources, unifying terminologies and unit bases across coefficient constants were unified, and compiling the data into a system of tables providing convenient indexing. As a result, 402 readily usable correlations for 352 sorption working pairs have been compiled, covering a wide range of sorbates including water, ammonia, methanol, ethanol, HFCs, HFOs, and hydrocarbons. The compiled database was also implemented into an open-source library named SorpPropLib, which can be directly used for calculating equilibrium vapor pressure of working pairs as well as supporting sorption systems simulation in various software.

The present paper deals with the experimental activity carried out at CNR-ITAE on two configurations of storages for seasonal heat accumulation. In particular, a commercial material (zeotype FAM Z02) and a composite sorbent (LiCl/vermiculite) were characterized and compared. Adsorption dynamics was evaluated through a Large Temperature Jump apparatus. The results were used to design lab-scale prototypes of the tow systems. Measurements indicated that FAM has a storage capacity up to 600 kJ/kg, while the composite has a storage capacity up to 1250 kJ/kg.

Thermal energy storage (TES) is a key technology to enhance the efficiency of energy systems as well as to increase the share of renewable energies. In this context, the present paper reports a literature review of the recent advancement in the field of adsorption TES systems. After an initial introduction concerning different heat storage technologies, the working principle of the adsorption TES is explained and compared to other technologies. Subsequently, promising features and critical issues at a material, component and system level are deeply analyzed and the ongoing activities to make this technology ready for marketing are introduced.

In Chap. 2, the two main methods to study the sorption dynamics for AHT cycles were widely described: (i) the Large Pressure Jump (LPJ) method, in which adsorption is initiated by a jump of pressure over the sample, is the most adequate for pressure-driven AHT cycles; (ii) the Large Temperature Jump (LTJ) method, in which adsorption is enabled by a temperature swing of a heat exchanger wall that is in contact with the adsorbent under an almost isobaric ad/desorption stage, is the proper choice for temperature-driven AHT cycles (see Chaps. 1 and 2). In this chapter, the main factors affecting the sorption dynamics will be highlighted for temperature-driven AHT cycles by the analysis of results achieved by the two versions (namely V-LTJ and G-LTJ) of the LTJ method.

This paper presents the experimental characterization and atomistic modelling of water sorption onto a commercial silicoaluminophosphate (SAPO-34) for sorption thermal storage applications. The measured adsorption isotherms were classified as type V, with a "S" shaped evolution which allows to obtain good sorption storage capacity already at low regeneration temperature (i.e. 80°C). The atomistic model approach demonstrated to be able to satisfactorily represents the isotherm of adsorption, with slight discrepancies at p/p0

This document is the deliverable "D3.1 - Optimization of the hybrid heat pump configuration and control strategy through dynamic modelling under different scenarios" of the European project "HYCOOL - Industrial Cooling through Hybrid system based on Solar Heat." (hereinafter also referred to as "HYCOOL", project reference: 792073). The present deliverable aims at defining a dynamic simulation tool for the modelling of the hybrid cascade chiller, which represents one of the core systems of the HYCOOL project. This system is based on the coupling of a thermally driven adsorption chiller and a vapour compression chiller. In particular, the operation of the adsorption chiller is primarily meant to dissipate the heat of condensation that needs to be rejected by the vapour compression chiller. In this way, reducing the temperature lift between evaporator and condenser, less compression work is needed and the energy efficiency ratio is improved. Firstly, a components selection was performed, in order to identify the most suitable refrigerant as well as the sizing of the heat exchangers, compressor and valves of the two machines. Particularly the refrigerant for the vapour compression chiller was selected by means of a thermodynamic optimization, coupled to considerations regarding the compressor sizing and its environmental impact. An innovative natural refrigerant, R290 (i.e. propane) was identified as the most promising for this application, also according to the current technology being developed by FAHRENHEIT. The dynamic model was implemented in the language Modelica through the software Dymola. It allowed exploiting standard libraries for the modelling of relevant components as well as physical phenomena, such as heat and mass transfer, which can be easily adapted to properly model the defined technology under investigation. For this reason, for all the components of the hybrid chiller, technical data from manufacturer datasheets and existing experimental data were used to make the model reliable. The implemented model was successfully validated against experimental data collected on a lab-scale prototype previously produced by FAHRENHEIT and tested at the CNR ITAE lab. The operation of a 20 kW cooling power machine, which will represent the rated power for the lab-scale experimental activity during the T3.3, was then simulated under different conditions. They represent the operation under variable heat source and sink and implement an experimental dynamic load profile provided by GIVAUDAN, whose meaningfulness can be extended also for the application to the Bo de Debò pilot plantThese simulations were used to optimize the ratio between cooling powers of the adsorption chiller and vapour compression chiller, demonstrating that the adsorption chiller needs to provide at least 20% more cooling power than the vapour compression one, to properly operate the hybrid configuration. Furthermore, some Key Performance Indicators were defined, namely, the cooling capacity and the thermal COP of the adsorption chiller and the average inlet temperature at the condenser of the vapour compression chiller. These were employed to comparatively evaluate the operation of the cascade chiller under different boundary conditions, thus highlighting which might be the most effective control strategy to maximize the overall efficiency. The outcome of this analysis was the identification of performance maps, as function of boundary conditions and part load, useful to identify the best management strategy of the cascade chiller and to give a comprehensive indication on its operation in different conditions The implemented simulation tool will be further refined as soon as all the components will be designed during the T3.2 and then used, during the T3.3 to identify further management strategies to be tested on the lab-scale prototype. The performance map obtained, which summarises the energy flows in and out from the hybrid heat pump will be employed during WP5 and WP6 as input for the control development and system integration design. Finally, it will represent a useful tool throughout the project also to support the sizing of the hybrid chiller for the demo site installations.

Despite significant progress, the AHT technology as yet remains unfinished and expensive, so that there is still a big room for its improvement [1, 2]. This concerns, first of all, enhancement of the AHT dynamics, like the ad/desorption rate and finally the specific power that is the main figure of merit of the AHT dynamic performance. Therefore, further R&D activity is necessary to realize the potential economic and ecological advantages of the AHT technology [3]. The optimization of the AHT dynamic performance is a multi-purpose task that includes, first of all, the improvement of the “adsorbent–heat exchanger” unit.

In the present work, adsorption performances of an innovative composite adsorber, based on SAPO-34-silicone composite macro-cellular foams, are reported. The choice of a foamed structure was assessed to improve the water vapor access towards the embedded zeolite keeping good adsorption heat pump dynamic performance. Depending on zeolite amount used as filler, zeolite/silicone foams evidenced a soft and open cell configuration (low zeolite content) or rigid and closed one (high zeolite content). Morphological analysis evidenced that the cellular structure of the foam is homogeneous and well distributed along the foam cross section. Adsorption tests showed that the adsorbent foamed samples have very effective adsorption capabilities indicating that the porous structure of the filled pure zeolite was not obstructed. SAPO-34 filler contributed actively, with an efficiency above 90%, to the adsorption performances of the composite foam. Starting from experimental equilibrium data, a simple thermodynamic analysis based on energy balances was carried out for air conditioning application. Results of the analysis demonstrated that foam technology can guarantee cooling COP up to 7% higher than that estimated for the typical adsorber solution based on loose adsorbent grains inside an aluminum finned-flat tube heat exchanger, which is very promising for practical application in adsorption heat pumps.

In this report, formulations, chemical composition (by EDX analysis), adsorption isotherms measurement and XRD patterns for a first series of ions exchanged zeolite Y are presented and compared with the original high-silica Y zeolite samples. Furthermore, adsorption isotherm at T=35°C of the commercial UOP DDZ70 zeolite was also measured to assess the adsorption target to be reached

The aim of the present paper is the experimental characterization of adsorbent materials suitable for practical applications in adsorption refrigeration systems, employing ethanol as refrigerant. Different commercial activated carbons as well as a properly synthesized porous composite, composed of LiBr inside a silica gel host matrix, have been tested. A complete thermo-physical characterization, comprising nitrogen physi-sorption, specific heat and thermo-gravimetric equilibrium curves of ethanol adsorption over the sorbents, has been carried out. The equilibrium data have been fitted by means of the Dubinin – Astakhov equation. On the basis of the experimental data, a thermodynamic evaluation of the achievable performance of each adsorbent pair has been estimated by calculating the maximum COP (Coefficient of Performance) under typical working boundary conditions for refrigeration and air conditioning applications. The innovative composite material shows the highest thermodynamic performances of 0.64–0.72 for both tested working conditions. Nevertheless, the best carbonaceous material reaches COP value comparable with the synthesized composite. The results have demonstrated the potential of the chosen adsorbents for utilization in adsorption cooling systems.

This paper presents a novel experimental protocol for the evaluation of the thermodynamic performance of working pairs for application in adsorption heat pumps and chillers. The proposed approach is based on the experimental measurements of the main thermo-physical parameters of adsorbent pairs, by means of a DSC/TG apparatus modified to work under saturated vapour conditions, able to measure the ads-/desorption isobars and heat flux as well as the adsorbent specific heat under real boundary conditions. Such kind of activity allows to characterize the thermodynamic performance of an adsorbent pair allowing the estimation of the thermal Coefficient Of Performance (COP) both for heating and cooling applications, only relying on experimental values. The experimental uncertainty of the method has been estimated to be around 2%, for the COP evaluation. In order to validate the proposed procedure, a first test campaign has been carried out on the commercial adsorbent material, AQSOA-Z02, produced by MPI (Mitsubishi Plastics Inc.), while water was used as refrigerant. The proposed experimental methodology will be applied on several other adsorbent materials, either already on the market or still under investigation, in order to get an easy and reliable method to compare thermodynamic performance of adsorptive working pairs.

Owing to encouraging energy saving potential, adsorption heat transformers are considered as promising alternative to compression systems. However the enhancement of their specific power is required for their broader dissemination. This paper aims at the dynamic optimization of the Ad-HEx (adsorber/heat exchanger) unit operating with the novel working pair "LiBr/silica - ethanol", which is characterized by high sorption difference under typical conditions of ice making and air conditioning cycles. The comparative investigation of various Ad-HEx configurations, namely thin beds of loose sorbent grains located on a flat metal plate and loaded into finned flat-tube heat exchangers was carried out. The effects of the adsorbent grain size, Ad-HEx geometry were explored in detail, and the main factors affecting sorption dynamics were revealed. The intra-particle diffusion of ethanol vapor and heat transfer between the support and the sorbent bed were shown to affect the sorption rate for flat sorbent bed configuration. For the configurations based on finned flat-tube heat exchangers, additional effects of the inter-particle diffusion or/and residual air were detected. On the base of the main findings obtained the practical recommendations on optimization of the Ad-HEx unit were formulated in order to enhance the specific cooling power of the adsorptive chiller. © 2014 Elsevier Ltd. All rights reserved.

In this study, the thermodynamic analysis of several adsorption working pairs for adsorption heat storage applications at domestic level is presented. The selected working pairs employ different working fluids (i.e. water, ethanol, ammonia, methanol) and different adsorbent materials such as classical zeolites, silica gels, alumino-phosphates, composite sorbents and activated carbons. The simulations have been performed taking into account desorption temperatures in the range between 80 °C and 120 °C, compatible with non-concentrating solar thermal collectors, under seasonal heat storage working conditions. The composite sorbent MWCNT-LiCl with both water and methanol as working fluid showed the highest heat storage density under practical working boundary conditions. Among the standard adsorbents, the zeotype AQSOA Z02 showed promising achievable heat storage densities. Classical working pairs, such as zeolite 13X/water, commonly employed for heat storage applications, are not suitable for this working range. Finally, also the influence of the metal to sorbent mass ratio, due to the heat exchanger, was investigated, demonstrating that it can reduce the achievable amount of heat released to the user up to 30%.

Main goals of the activity were: i) water ad/desorption isotherms measurement for 2 high-silica Y zeolite samples having different structural Si/Al ration; ii) presentation of first results on the preparation of several exchanged Y-type zeolite samples. Firstly, the experimental gravimetric unit used for water adsorption measurement at equilibrium is presented. Then, the measurement procedure is precisely described. An important part of the measurement methodology assessment was the verification of the reliability of the instrument. With this aim, the same measurement protocol has been repeated few times on the same sample. Concerning the Ions Exchange experiments, a first series of ions exchanged zeolite Y have been prepared and characterized. More specifically, the preparation procedure for La(III), Ce(III), Pr(III), Nd(III) and Sm(III)-exchanged zeolites is described. Structural and chemical composition of the prepared samples have been verified by XRD and EDX analyses. Results achieved are discussed and compared with the original Y-type zeolite.

In the present work, an experimental study on a lab-scale adsorption refrigerator, based on activated carbon/ethanol working pair is reported. An extensive testing campaign has been carried out at the CNR ITAE laboratory, with multiple aims. First, the performance has been evaluated in terms of both COP and Specific Cooling Power (SCP), under different boundary conditions, including both air conditioning and refrigeration applications. Attractive SCPs, up to 180 W/kg and 70 W/kg for air conditioning and refrigeration, respectively, were measured. Under the same conditions, COP between 0.17 and 0.08 were obtained. In addition, different management strategies, namely, heat recovery between adsorbers and re-allocation of phase durations, were evaluated to identify their influence on the system. Both strategies confirmed the possibility of increasing COP and SCP up to 40% and 25%, respectively. Moreover, a design analysis based on the experimental results has been carried out, to suggest possible improvements of the system. The obtained results demonstrated the possibility of employing a non-toxic refrigerant like ethanol reaching performance comparable with other harmful refrigerants like ammonia and methanol.

The present report summarizes the results of the wet ageing process at 60°C for a week, on two samples of the commercial adsorbent material AQSOA-Z02, with grain size of 10?m and 15 ?m, produced by Mitsubishi Plastic Inc. (MPI). The stability of the aged samples have been characterized by means of adsorption equilibrium curves measurements and through morphological investigation by means of SEM technique.

Thermal energy storage systems have gained interest in recent years, both for cold and heat applications, daily or seasonal. Among them, thermochemical storage have shown great potentialities, but still only few experimental activities on prototypal systems are reported. Aim of the present paper is to describe a test set-up located at CNR-ITAE and devoted to the characterization of thermochemical storages. A testing procedure for the assessment of this kind of devices has been tested as well, proving a good starting point towards the definition of a more complete protocol.

The enhancement of the efficiency of adsorption heat pumps depends on the adsorption capacity of the adsorbent materials as well as on heat transfer efficiency between the adsorbent material in contact with the heat exchanger and the heat transfer fluid. The heat transfer efficiency can be improved by coating the heat exchangers with a thin layer of adsorbent material consolidated by means of a proper binder. In the present paper, three innovative silane-based adsorbent coating compositions, employing a commercial SAPO 34 as adsorbent material, are presented. Their physico-chemical and the mechanical features have been deeply studied, demonstrating promising characteristics which make them as an attractive solution to enhance achievable power density of adsorption machines.

The third phase of the collaborative project involving CNR ITAE and Toyota Motor Corporation (TMC hereafter) is oriented towards the further investigation of hydrothermal stability of the commercial adsorbent material AQSOA-Z02 with grain size of 10?m and 15 ?m, produced by Mitsubishi Plastic Inc. (MPI), under ageing conditions already investigated during the second phase of the project.