Academic literature on the topic 'Adsorption Cooling'

Important parameters used for adsorption chillers, e.g. cooling capacity, coefficient of performance, are strictly dependent on heat and mass transfer conditions between adsorbent mass and the cooling/heating medium. With the aim of energy efficiency increasing it is essential to reduce heat transfer resistance. Different bed configurations and heat exchangers constructions are recommended for adsorption bed application. In the paper the review of commonly used adsorption bed configurations, i.e. loose-grain beds or fixed beds, is presented. Also, different heat exchangers for adsorption technology were described. The characteristic features of commonly applied constructions, both for commercial use and scientific research, were presented. The experimental studies presented in the literature were investigated and the substantial conclusions from the literature review are mentioned. Also, the proposition of new adsorption bed construction using the binder and additives was mentioned.

In the present paper, the effect of desorption temperature on the performance of adsorption cooling systems driven by waste heat from fuel cells was analyzed. The studied adsorption cooling systems employ activated carbon fiber (ACF) of type A-20–ethanol and RD type silica gel–water as adsorbent–refrigerant pairs. Two different temperature levels of waste heat from polymer electrolyte fuel cell (PEFC) and solid oxide fuel cell (SOFC) are used as the heat source of the adsorption cooling systems. The adsorption cycles consist of one pair of adsorption–desorption heat exchanger, a condenser and an evaporator. System performance in terms of specific cooling capacity (SCC) and coefficient of performance (COP) are determined and compared between the studied two systems. Results show that silica gel–water based adsorption cooling system is preferable for effective utilization of relatively lower temperature heat source. At relatively high temperature heat source, COP of ACF–ethanol based adsorption system shows better performance than that of silica gel–water based adsorption system.

Adsorption refrigeration is an effective way to use low-grade energy sources such as industrial waste heat without damaging the environment. A novel exhaust-driven adsorption icemaker on a fishing boat is introduced in this paper. Based on the previous study, combining with the single adsorption cooling tube technique, this paper presents an adsorption cooling unit with unique structure driven by exhaust waste heat (hereinafter referred to as "waste heat cooling tube" WHCT). Different with the previous tubular structured adsorption bed, WHCT is made of seamless stainless steel pipe, the adsorbent bed, evaporator / condenser are all placed in one tube. Adsorption working pair of calcium chloride-ammonia has been proposed and developed for adsorption cooling. The working principle and structure are introduced in this paper.

The adsorption cooling systems have been developed to replace vapor compression due to their benefits of being environmentally friendly and energy saving. We prepared zeolite-4A and experimental cooling performance test of zeolite-water adsorption system. The adsorption cooling test-rig includes adsorber, evaporator, and condenser which perform in vacuum atmosphere. The maximum and minimum water adsorption capacity of different zeolites and COP were used to assess the performance of the adsorption cooling system. We found that loading zeolite-4A with higher levels of silver and copper increased COP. The Cu6%/zeolite-4A had the highest COP at 0.56 while COP of zeolite-4A alone was 0.38. Calculating the acceleration rate of zeolite-4A when adding 6% of copper would accelerate the COP at 46%.

Heat driven adsorption cycles use heat sources ranging in temperature from 80 - 150 °C to provide cooling, and have been used in both air conditioning and refrigeration applications. Adsorbent heat pumps operate with low cost, simple components, and very little vibration, making them appealing as an alternative heat pump technology. However, they have been limited thus far to commercial and industrial scale applications. To date, adsorption systems have predominantly used natural or industrial waste streams as heat sources in the 10s of kW range. This work expands the scope of adsorption applications to include heat driven cooling at small capacities (watts) and mobile cooling without electronic controls. Autonomous heat driven adsorption system controls are proposed and tested for these systems. Component and system level models are developed for design and assessment. Major trends in system performance with scale are identified and the causes for these scaling effects are presented. New adsorbent bed designs are proposed and modeled for small-scale adsorption systems. The small-scale adsorbent bed designs are fabricated and tested. Models are validated and refined based on the experimental results. Through a combination of modeling and experimental results, this work demonstrates the feasibility of adsorption system application at capacities that two orders of magnitude lower than any previously demonstrated work.

A cutting edge man-portable AVMEC cooling garment was demonstrated to be able to provide sufficient cooling for personnel working at mediate activity loads. Studies were first carried out in a well controlled vacuum desiccator at room temperature to elucidate the effects of several key parameters on the performance of an AVEC device, which was similar to AVMEC except that membrane was not involved. Under the best condition, an average cooling capacity of 179 W/M2 was achieved in a period of four hours and cooling continued at a slowly declining rate for another four hours afterward. The temperature of water was maintained at approximately 12.5 oC after the pseudo steady state was established. Then, it was shown that the AVMEC cooling pads were able to provide a cooling capacity of 277.4 W/m2 in a 37 oC ambient environment (incubator). The temperature of the cooling core surface was maintained in a range of 20 – 21.8 oC in the one-hour test period. No power supply was required except for the initialization stage, which took 5 minutes. Furthermore, human subject tests with or without wearing NWBC (Nuclear Warfare Biological and Chemical) suit demonstrated that, a AVMEC garment composed of 12 cooling pads were able to maintain the core body temperature of the subjects below 38.5 oC for up to 90 minutes while the subject was walking on a treadmill at a speed of 2 miles per hour in an environment of 40 oC and 50% RH (relative humidity). These results indicate that the AVMEC garment is a promising man-portable personal cooling technology.

Due to the fact that the worldwide energy consumption caused by cooling devices in buildings has been increasing steadily and also the fact that the pressure has been rising to provide this cooling energy with environmentally friendly technology, solar powe.re~ DEC-systems (Desiccative and Evaporative Cooling) have begun capturing increasing interest over the past few years. , However, up to now little experience has been gained in the operation of these systems and thus currently little information is available about the performance, the efficiency, the control strategy and the best component choice. This lack of knowledge has resulted in a low rate of acceptance of, this technology so far. The studies presented in this thesis serve as a contribution to the advancement of DEC technology by providing fundamental knowledge about the operation and attainable performance of these systems. A comprehensive study of desiccant wheels was undertaken which provides detailed information about the operation and the achievable dehumidification performance of this component. A detailed simulation model for desiccant wheels was developed and verified with measured data from a desiccant wheel test plant. Additionally, two commercially used DEC-systems (one in a public library in Spain and the other in a plastics processing factory building in Germany) were monitored for the purposes of evaluating the performance of these systems and resolving existing problems in their operation and control strategies. In spite of the generally positive validation of the planned and expected cooling performances in both cases, the monitoring also showed that there are considerable possibilities· for improvement, especially with the regulation of the system.

Environmental concerns regarding climate change and ozone depletion urge for a paradigm shift in the cooling production. The cooling demand exhibits an alarmingly increasing trend, thus its satisfaction in a sustainable manner is imperative. Adsorption cooling systems (ACSs) are a potential candidate for a sustainable future of cooling production, since they can utilize solar energy or waste heat, as well as they can employ substances with zero ozone depletion and global warming potential. The objective of this thesis is to contribute to the investigation and improvement of ACSs, through the development of two computational models - which approach ACSs from different perspectives - and their respective utilization for the conduction of related numerical studies. The first research direction focuses on the design of the adsorption reactor, the most vital component of ACSs. Its geometrical configuration is determinant for the system performance. The reactor design is a crucial task since it creates a dichotomy between the two performance indicators - the Specific Cooling Power (SCP) and the Coefficient of Performance (COP). Individual optimizations based on the SCP and the COP would result in completely opposite geometrical configurations. A computational model for the simulation of adsorption packed bed reactors was developed, capable of simulating any potential reactor geometry. A multi-timestep approach is adopted, resulting in a drastic reduction of the computational cost of the simulations. Verification and validation assessments were performed in order to evaluate the reliability of the model. Two major studies were conducted within this research direction. The first aspires to provide a comparison between five reactor geometries, motivated by the lack of comparability across different studies in the literature. Thirteen cases of each geometry are simulated, by varying the fin thickness, fin length and solid volume fraction. The second study pertains to a thorough investigation of a geometry that remained underexplored hitherto - the hexagonal honeycomb adsorption reactor. A parametric study is conducted with respect to the three dimensions that define the geometry, as well as for various operating conditions. The second research direction is dedicated to the investigation of adsorption cooling systems, and in particular, to their integration within a wider thermal system, a solar-cooled building. Such integration is not straight-forward due to thermal inertia effects and the inherent cyclic operation of ACSs, as well as due to the dependence on an intermittent source and an auxiliary unit, with a clear objective to prioritize solar energy. A numerical model was developed using 1-d models for the adsorption reactors and 0-d models for the evaporator and condenser. The model is validated against experimental results found in the literature. The model is coupled to the generic optimization tool GenOpt, thus allowing the conduction of optimization studies. The ACS model is then coupled to solar collectors and thermal storage models, as well as to a building model. The latter was previously developed in the CTTC laboratory. This coupling results in a comprehensive simulation tool for adsorption-based solar-cooled buildings. A case study for a solar-cooled office is considered, with the objective to investigate the potential of satisfying its cooling demand using solar energy. A control strategy is proposed based on variable cycle duration, using optimized values for the instantaneous operating conditions. The variable cycle duration approach allows to satisfy the cooling demand using significantly less solar collectors or less auxiliary energy input. The potential carbon dioxide emissions avoidance is calculated between 28.1-90.7% with respect to four scenarios of electricity-driven systems of different performance and carbon emission intensity.
La preocupació mediambiental sobre el canvi climàtic i l'esgotament d'ozó exigeix un canvi de paradigma en la producció de fred. La demanda de refredament mostra una tendència alarmant creixent, així és imperatiu satisfer-la de forma sostenible. Els sistemes de refredament per adsorció (ACS) són un candidat per a un futur sostenible de la producció de fred, ja que poden utilitzar energia solar o calor residual, emprant substàncies amb zero potencial d'esgotament d'ozó i d'escalfament global. L'objectiu d'aquesta tesi és contribuir a la investigació i millora dels ACS, mitjançant el desenvolupament de dos models computacionals - que aborden els ACS des de diferents perspectives - i la seva utilització per a la realització d'estudis numèrics. La primera línia d'investigació se centra en el disseny del reactor d'adsorció, el component més important dels ACS. La seva configuració geomètrica és determinant pel rendiment de sistema. El seu disseny és una tasca crucial, ja que crea una dicotomia entre la potència específica de refrigeració (SCP) i el coeficient de rendiment (COP). Les optimitzacions individuals basades en el SCP i el COP resultarien a configuracions geomètriques completament oposades. S'ha desenvolupat un model computacional per a la simulació de reactors d'adsorció tipus "packed bed", capaç de simular reactors de qualsevol geometria. S'adopta una estratègia multi-timestep, que permet una dràstica reducció del cost computacional de les simulacions. La fiabilitat del model es va avaluar a través de processos de verificació i validació. Dins d'aquesta línia de recerca es van realitzar dos estudis principals. El primer aspira a proporcionar una comparació entre cinc geometries de reactors, motivat per la falta de comparabilitat entre diferents estudis en la literatura. Es simulen tretze casos de cada geometria, variant el gruix de les aletes, la seva longitud i la fracció de volum de sòlid. El segon estudi presenta la investigació d'una geometria sub-explorada previament, el reactor d'adsorció de honeycomb hexagonal. Es realitza un estudi paramètric pel que fa a les tres dimensions que defineixen la geometria, així com per a diverses condicions de funcionament. La segona línia de recerca es dedica a la investigació dels ACS. i en particular, a la seva integració dins d'un sistema tèrmic més ampli, un edifici refredat per energia solar. Aquesta integració no és senzilla a causa de la inèrcia tèrmica i a el funcionament cíclic inherent dels ACS, així com a la dependència d'una font intermitent i d'un sistema auxiliar, amb l'objectiu de prioritzar l'energia solar. S'ha desenvolupat un model numèric utilitzant models 1-d pels reactors i models 0-d per l'evaporador i el condensador. El model es va validar amb resultats experimentals trobats en la literatura. El model es va acoblar amb l'eina d'optimització genèrica GenOpt, permetent així estudis d'optimització. El model ACS es va acoblar amb models de col·lectors solars, emmagatzematge tèrmic i amb un model d'edifici. Aquest últim va ser desenvolupat prèviament al CTTC. Aquest acoblament resulta a una eina de simulació integral per a edificis refredats per energia solar utilitzant adsorció. Es considera un cas d'estudi per a una oficina refredada per energia solar, amb l'objectiu d'investigar el potencial de satisfer la seva demanda de fred utilitzant energia solar. Es proposa una estratègia de control basada en la duració variable del cicle, utilitzant valors optimitzats per a les condicions instantànies. La durada variable d'el cicle permet satisfer la demanda utilitzant una quantitat significativament menor de col·lectors solars o un menor aportació d'energia auxiliar. Les emissions de CO2 evitades es calculen entre 28.1-90.7% respecte a quatre escenaris de sistemes elèctrics de diferent rendiment i intensitat d'emissions de carboni.

This thesis investigates the feasibility of producing electricity and cooling simultaneously utilising low-grade heat sources by incorporating an expander within the adsorption cooling system or by integrating an Organic Rankine Cycle with water adsorption cooling system. Advanced physical adsorbent materials have been investigated for the first time to generate cooling and electricity simultaneously utilising CPO-27(Ni), MIL101(Cr), and AQSOA-Z02 and compared to commonly used Silica-gel. Two innovative configurations of water adsorption systems for cooling and electricity were investigated. In the first configuration, the two-bed basic adsorption cooling system (BACS) is improved by including an expander within the system. In the second configuration, the BACS and ORC cycle are integrated. Four different scenarios of systems integration based on the way of powering the ORC and the adsorption system were investigated. Also, detailed CFD simulations of small-scale radial inflow turbines are developed for both configurations. Also, a novel experimental facility is developed to integrate ORC with two-bed adsorption cooling system to validate the numerical models and proof the concept of producing power as well as cooling, where maximum specific cooling power of 252 W/kgads and specific power and of 162 W/kgads can be achieved with maximum deviation of less than 17%.

[EN] This PhD study deals with the modelling of an adsorption system designed to provide air conditioning for vehicles, and is driven by the waste heat available from the water/glycol cooling circuit of the engine. The system is based on the sequential heating/cooling of two sorption beds containing a solid sorption material which desorbs or adsorbs water vapour. The condensation of the vapour is carried out by a cooling circuit while the subsequent evaporation of the condensed liquid is employed to produce the cooling effect, generating chilled water, which is then employed to cool down the air of the cabin. The developed model is fully dynamic and is based on zero-dimensional lumped parameter models for all the necessary components of the overall system including the engine, the beds, the heating circuit, the cooling circuit, the chilled water circuit and the vehicle cabin. The sorption bed model takes into account the non-equilibrium of the adsorption and desorption processes and is able to work with any kind of adsorbent materials, but the study has been restricted to silica gel and zeolite which are among the most appropriate materials for this application. The model is employed to simulate a standard driving cycle of a vehicle, evaluating the instantaneous available heat from the engine cooling system and the dynamic behaviour of the described sorption A/C system, resulting in the estimation of the evolution of the cabin temperature along the cycle. The model of the overall system has been developed under the MATLAB Simulink programming environment. The model of the adsorption system has been first validated against experimental results, showing its excellent capabilities to predict the dynamic behaviour of the system. The model was then used to analyse the influence of the main design parameters of the bed and the main operation parameters on the system's performance: cooling capacity and coefficient of performance (COP). This was done in order to provide rules for the optimal design and operation of this kind of systems. Finally, the model has been employed to analyse the overall system (engine, adsorption system, heating and cooling circuits, chilled water circuit and cabin) performance along a standard driving cycle, under various operation strategies with regards to the initial state of the adsorbent material in the beds, and operation conditions both for a car and a truck. The results show the difficulties of activating the system at the initial periods of the cycle, when the engine is warming up, and the difficulties to synchronise the operation of the system with the availability of waste energy. They also highlight the limitation in capacity of the designed system, showing that it would not able to fulfil the comfort requirements inside the cabin in hot days or after soaking conditions. Part of this PhD study was carried out in the frame of an R&D project called "Thermally Operated Mobile Air Conditioning Systems - TOPMACS", financially supported by the EU under the FP6 program, which was devoted to the evaluation of the feasibility and performance of potential sorption system solutions for the air conditioning of vehicles.
[ES] Esta tesis doctoral se centra en el modelado de un sistema de adsorción diseñado para proporcionar aire acondicionado de vehículos a partir del calor residual disponible en el circuito de refrigeración de agua/glicol del motor. El sistema se basa en el calentamiento/enfriamiento secuencial de dos reactores que contienen un material adsorbente sólido que desorbe o absorbe vapor de agua. La condensación del vapor se lleva a cabo mediante un circuito de refrigeración, mientras que la posterior evaporación del agua condensada se emplea para producir agua fría, que se emplea finalmente en enfriar el aire de la cabina. El modelo desarrollado es completamente dinámico y se basa en modelos cero dimensionales de parámetros concentrados, para todos y cada uno de los componentes del sistema global incluyendo el motor, los reactores, el circuito de calentamiento, el circuito de enfriamiento, el circuito de agua fría y la cabina del vehículo. El modelo del reactor contempla el no equilibrio de los procesos de adsorción o desorción y es capaz de trabajar con cualquier par de materiales adsorbentes. No obstante el estudio se ha restringido a gel de sílice y zeolita que se encuentran entre los materiales más adecuados para esta aplicación. El modelo se emplea para simular un ciclo de conducción estándar del vehículo, evaluando el calor disponible instantáneamente en el sistema de refrigeración del motor, y el comportamiento dinámico del sistema descrito adsorción-Aire Acondicionado, permitiendo como resultado principal la estimación de la evolución de la temperatura de la cabina a lo largo el ciclo. El modelo del sistema global se ha desarrollado en el marco del entorno de programación MATLAB Simulink. El modelo del sistema de adsorción se ha validado primero contra resultados experimentales demostrando las excelentes capacidades del modelo para predecir el comportamiento dinámico del sistema. A continuación, el modelo se ha aplicado para analizar la influencia de los principales parámetros de diseño del reactor, y de los principales parámetros de operación, sobre el rendimiento del sistema: la capacidad y coeficiente de operación (COP), con el fin de proporcionar directrices para el diseño y operación óptima de este tipo de sistemas. Por último, el modelo ha sido empleado para analizar el funcionamiento y prestaciones del sistema en su conjunto (motor, sistema de absorción, los circuitos de calefacción y refrigeración, circuito de agua fría, y la cabina) a lo largo de un ciclo de conducción estándar, bajo diferentes estrategias de operación en lo que se refiere al estado inicial del material adsorbente en los reactores, y las condiciones de operación, para el caso de un coche, y para el de un camión. Los resultados muestran las dificultades de la activación del sistema en los periodos iniciales del ciclo, cuando el motor se está calentando, y las dificultades para sincronizar el funcionamiento del sistema con la disponibilidad de energía térmica excedente del motor, así como la limitación en la capacidad de enfriamiento del sistema diseñado, que no resulta capaz de satisfacer los requerimientos mínimos de confort dentro de la cabina en los días calurosos o de enfriarlo con suficiente rapidez cuando el vehículo ha estado estacionado bajo el sol durante varias horas. Parte de este estudio de doctorado se ha llevado a cabo en el marco de un proyecto de I + D denominado " Thermally Operated Mobile Air Conditioning Systems - TOPMACS", financiado parcialmente por la UE en el marco del programa FP6, y que perseguía la evaluación de la viabilidad y el potencial de aplicación de soluciones de sistemas de adsorción activadas por el calor residual del motor para el aire acondicionado de vehículos.
[CAT] Aquesta tesi doctoral es centra en el model d'un sistema d'adsorció dissenyat per a proporcionar aire acondicionat a vehicles a partir de la calor residual disponible al circuit de refrigeració d'aigua / glicol del motor. El sistema es basa en l'escalfament / refredament seqüencial de dos reactors que contenen un material adsorbent sòlid que desorbeix o absorbeix vapor d'aigua. La condensació del vapor es porta a terme mitjançant un circuit de refrigeració, mentre que la posterior evaporació de l'aigua condensada s'utilitza per a produir aigua freda, que s'empra finalment en refredar l'aire de la cabina. El model desenvolupat és completament dinàmic i es basa en models zero dimensionals de paràmetres concentrats, per a tots i cada un dels components del sistema global incloent el motor, els reactors, el circuit d'escalfament, el circuit de refredament, el circuit d'aigua freda i la cabina del vehicle. El model del reactor contempla el no equilibri dels processos d'adsorció o desorció i és capaç de treballar amb qualsevol parell de materials adsorbents. No obstant això, l'estudi s'ha restringit a gel de sílice i zeolita que es troben entre els materials més adequats per a aquesta aplicació. El model s'utilitza per a simular un cicle de conducció estàndard del vehicle, avaluant la calor disponible instantàniament en el sistema de refrigeració del motor, i el comportament dinàmic del sistema descrit Adsorció-Aire Acondicionat, permetent com a resultat principal l'estimació de l'evolució de la temperatura de la cabina al llarg del cicle. El model del sistema global s'ha desenvolupat en l'entorn de programació MATLAB Simulink. El model del sistema d'adsorció s'ha validat primer amb resultats experimentals demostrant les excel¿lents capacitats del model per a predir el comportament dinàmic del sistema. A continuació, el model s'ha aplicat per analitzar la influència dels principals paràmetres de disseny del reactor, i dels principals paràmetres d'operació, sobre el rendiment del sistema: la capacitat i coeficient d'operació (COP), amb la finalitat de proporcionar directrius per al disseny i operació òptima d'aquest tipus de sistemes. Finalment, el model ha estat utilitzat per analitzar el funcionament i prestacions del sistema en el seu conjunt (motor, sistema d'absorció, els circuits de calefacció i refrigeració, circuit d'aigua freda, i la cabina) al llarg d'un cicle de conducció estàndard, sota diferents estratègies d'operació pel que fa a l'estat inicial del material adsorbent en els reactors, i les condicions d'operació, per al cas d'un cotxe, i per al d'un camió. Els resultats mostren les dificultats de l'activació del sistema en els períodes inicials del cicle, quan el motor s'està escalfant, i les dificultats per sincronitzar el funcionament del sistema amb la disponibilitat d'energia tèrmica excedent del motor, així com la limitació en la capacitat de refredament del sistema dissenyat, que no resulta capaç de satisfer els requeriments mínims de confort dins de la cabina en els dies calorosos o de refredar amb suficient rapidesa quan el vehicle ha estat estacionat sota el sol durant diverses hores. Part d'aquest estudi de doctorat s'ha dut a terme en el marc d'un projecte d'I + D denominat "Thermally Operated Mobile Air Conditioning Systems - TOPMACS", finançat parcialment per la UE en el marc del programa FP6, i que perseguia l'avaluació de la viabilitat i el potencial d'aplicació de solucions de sistemes d'adsorció activats per la calor residual del motor per a l'aire condicionat de vehicles.
Verde Trindade, M. (2015). MODELLING AND OPTIMIZATION OF AN ADSORPTION COOLING SYSTEM FOR AUTOMOTIVE APPLICATIONS [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/54120
TESIS

Growing need for application of electronics at temperatures beyond their rated limit, (usually > 150 °C) and the non availability of high temperature compatible electronics necessitates thermal management solutions that should be compact, scalable, reliable and be able to work in environments characterized by high temperature (150 -250 °C), mechanical shock and vibrations. In this backdrop the proposed research aims at realization of an adsorption cooling system for evaporator temperatures in the range of 140 °C-150 °C, and condenser temperature in the range of 160 °C-200 °C. Adsorption cooling systems have few moving parts (hence less maintenance issues), and the use of Thermo-Electric (TE) devices to regenerate heat of adsorption in between adsorbent beds enhances the compactness and efficiency of the overall 'ThermoElectric-Adsorption' (TEA) system. The work presented identifies the challenges involved and respective solutions for high temperature application. An experimental set up was fabricated to demonstrate system operation and mathematical models developed to benchmark experimental results. Also, it should be noted that TEA system comprises TE and adsorption chillers. A TE device can be a compact cooler in its own right. Hence a comparison of the performance of TEA and TE cooling systems has also been presented.

In this thesis, yearly performance of the solar adsorption cooling system which is proposed to be installed to a residential building in Antalya is theoretically investigated in detail. Firstly, thermodynamic designs of the adsorption cooling cycle for three different types of cycles which are intermittent, heat recovery and heat &
mass recovery cycles are presented. Secondly, adsorption characteristics of three adsorbent/adsorbate pairs which are zeolite-water, silica gel-water and activated carbon-methanol are given. Following this, load side (i.e., building) of the system is designed and parameters that should be considered in building design are presented. Then, solar-thermal cooling system design methodology with an emphasis on solar fraction is presented. In addition, system parameters effecting the performance of the adsorption cooling system are analyzed and results are presented. Finally, economic analysis is done in order to understand the economic feasibility of the solar-thermal cooling systems compared to conventional cooling systems. TRNSYS is used for the yearly simulations and an integrated model of the overall system is developed in TRNSYS. Since energy consumption and performance investigations of environment-dependent systems such as building HVAC, refrigeration systems and solar collectors usually require weather information, typical meteorological year (TMY) data for Antalya is also generated in order to be used in the analysis of the system parameters.

Energy consumption is continuously increasing around the world and this situation yields research to find sustainable energy solutions. Demand for cooling is one of the reasons of increasing energy demand. This research is focused on one of the sustainable ways to decrease energy demand for cooling which is the solar-powered adsorption cooling system. In this study, general theoretical performance trends of a solar-powered adsorption cooling system are investigated using TRNSYS and MATLAB. Effects of different cycle enhancements, working pairs, operating and design conditions on the performance are analyzed through a series of steady and seasonal-transient simulations. Additionally, a normalized model is presented to investigate the effects of size of the system, need for backup power, collector area and mass of adsorbent. Results are presented in terms of values and ratios of cooling capacity weighted COP. For the conditions explored, the thermal wave cycle, wet cooling towers, high evaporation temperatures and evacuated tube collectors produced the highest COP values. Moreover, the heat capacity of the adsorbent bed and its shell should be low for the simple and heat recovery cycles and the adsorbent bed should be cooled down to the condensation temperature for all cases to achieve the highest possible COP. The selection of working pair should depend on the temperature of the available heat source (solar energy in this study) since each working pair has a distinct operating temperature range. Furthermore, there is always a need for backup power for the analyzed location and the system.

This thesis work is intended to investigate energy and exergy performance of a low power prototype solar air conditioning system based on sorption materials. Its performance is analyzed in the light of both the First and Second Law of Thermodynamics and compared with conventional HVAC systems as well as with a further solar cooling technology based on desiccant wheels (Solar DEC). The adsorption machine based solar cooling plant was thoroughly designed and its thermal performance analysed in several operating conditions and then optimized according to a First Law and Second Law approach. The sensitivity theory was also applied in order to investigate the system response to deviations of some state variables from their nominal values. In this context a number of sensitivity coefficients were determined in relation to the most relevant design parameters. That provided useful information for control strategies in dynamic regime and hints for systems design and optimization. A general model was also developed and implemented in a computer code for the determination of the thermophysical properties of humid air streams when leaving a desiccant wheel, based on the Jurinak Method. An important outcome of this research work is that solar energy, with its relatively low energy potential -when made available by a low-to-medium temperature collector, such as with adsorption machines or desiccant wheels-, is a more appropriate energy source to air-conditioning than conventional systems, from a true thermodynamic point of view. In this sense its technology should be developed and its use should be encouraged.

This article presents a thermodynamic framework for the estimation of the minimum driving heat source temperature of an advanced adsorption cooling device from the rigor of Boltzmann distribution function and the condensation approximation of adsorptive molecules on adsorbent porous surface. The calculated resuls are validated with our own experimentally measured data. From this thermodynamic analysis, an interesting and useful finding has been established that it is possible to develop an adsorption cooling device that operates with a driving heat source temperature as low as 40 °C along with a coolant of temperature 30 °C. We have also presented here the thermodynamic modeling and experimental investigation of an advanced adsorption chiller for understanding its working principles.

For traditional adsorption cooling systems using silica-gel-like desiccant wheels, the moisture is removed from the air and stored in the desiccant wheels. The subsequent reactivation process is to dry the wheel by blowing hot air. The moisture is added to the dried air to take the advantage of evaporative cooling. Currently, the two processes are performed on the different sections of a wheel. However, the temperature of the reactivated part will be higher, and the residual heat will be dissipated into the air-conditioning space. Some researchers have reported to add another section to cool down the regenerative part. Unfortunately, the addition of cooling section decreases the working durations of other two sections. In this study, a novel desiccant-evaporative cooling process is proposed. The wheel is now stationary. Fans and air doors were designed to adjust various air flows to pass through the wheel to perform the dehumidifying, reactivation, and cooling inside the wheel. Most importantly, for each period, the desiccant wheel was used only to dehumidify, reactivate, or cool down. The air to cool the desiccant wheel was released outside, so no residual heat went to the air-conditioning space. The outdoor air was acquired to be heated and reactivate the desiccant wheel. The indoor was used to cool the wheel to achieve better cooling effects. An experimental prototype was designed and established. The air could be directed through the desiccant wheel. A controller was installed. The duration of the dehumidifying, reactivation, and cooling process could be set on the panel. The evaporative cooling process was performed by ten ultrasonic humidifiers. The hot air was from a liquid-to-air heat exchanger, and the hot water can be from a solar heater or any waste heat sources. Optimized sets of period durations were suggested. The criteria to end each process have been proposed for future automation. It is shown that the novel design is able to deliver cooler air. Although the cool air output is currently intermittent, a solution has been figured out and will be improved soon.

We have developed a thermodynamic framework to calculate adsorption cooling cum desalination cycle performances as a function of pore widths and pore volumes of highly porous adsorbents, which are formulated from the rigor of thermodynamic property surfaces of adsorbent-adsorbate system and the adsorption interaction potential between them. Employing the proposed formulations, the coefficient of performance (COP) and overall performance ratio (OPR) of adsorption cycle are computed for various pore widths of solid adsorbents. These results are compared with experimental data for verifying the proposed thermodynamic formulations. It is found from the present analysis that the COP and OPR of adsorption cooling cum desalination cycle is influenced by (i) the physical characteristics of adsorbents, (ii) characteristics energy and (iii) the surface-structural heterogeneity factor of adsorbent-water system. The present study confirms that there exists a special type of adsorbents having optimal physical characteristics that allows us to obtain the best performance.

An adsorption chiller is a type of chiller that uses heat input as the driving force for chemical compression of a refrigerant and provides cooling with low electrical consumption. An experimental setup was designed, instrumented, and constructed to meet constant inlet temperature and flow rate requirements for the commercially available adsorption chiller unit tested. Two types of tests were conducted, one with a constant hot water temperature which represents a district style heating system and another with a varying hot water temperature, representing a system using flat plate solar collectors. Numerous tests were run with constant inlet temperatures across the complete operating range of the chiller and at varying flow rates for each of the three main inputs. It was determined that variations in temperature had a much more significant impact on the performance of the chiller, compared to the variations in flow rate, which were almost negligible within tested range. Dynamic inlet temperature tests were run using the modified system which uses data from a weather file to simulate a system using flat plate solar collectors and vary the hot water inlet temperature to the system. The results showed that when the average hot water inlet temperature is lower than 60°C and higher than 75°C, the difference in performance between constant inlet temperature and dynamic inlet temperature tests was very small. However, the cooling capacity at 75°C was about 4 kWth greater than at 60°C. Majority of the test produced a thermal COP between 0.45 and 0.50. Therefore, based off the solar collector system’s capacity to maintain a suitable average hot water temperature, the cooling performance of the chiller can be deemed suitable for residential applications.