Valutazioni energetiche ed economiche relative all’utilizzo di un sistema frigorifero ad assorbimento alimentato da collettori parabolici

Innovative compact solar air conditioner based on fixed and cooled adsorption beds and wet exchangers

LCA of a solar heating and cooling system equipped with a small water–ammonia absorption chiller

The development of renewable energy technologies is a critical tool for reducing climate change and the reliance on fossil fuels. However, renewable energy technologies cannot be considered totally clean because they require energy consumption and have environmental impacts that cannot be neglected during their life cycle. In this paper, the life cycle assessment methodology was applied to assess resource use and other environmental burdens related to the entire life-cycle steps of a solar cooling plant. The investigated system works with an absorption chiller assisted by a solar plant. Two back-up configurations (hot back-up and cold back-up) were examined in two localities: Palermo (south…

Innovative Compact Solar Air Conditioner based on Fixed and Cooled Adsorption Beds and Wet Heat Exchangers

Abstract In this work, a new all-in-one compact solar air conditioner concept is presented. The system is mainly based on a new DEC process which utilises fixed and cooled adsorption beds operating in a batch process and two wet heat exchangers. The proposed innovative adsorption bed is a fin and tube heat exchanger commonly used in the air conditioning sector, wherein the spaces between the fins are filled with silica gel grains. The main feature of this component is to allow simultaneous dehumidification and cooling of air. Furthermore, since the component hosts a considerable amount of adsorption material, solar energy can be efficiently stored in the desiccant media in terms of accumula…

L'utilizzo dell'energia solare nel riscaldamento e nel raffrescamento degli edifici - Stato dell’arte, criteri di dimensionamento e potenzialità a scala regionale

Solar desiccant cooling system operating in Palermo (Italy): results and validation of simulation models

La climatizzazione estiva degli edifici con l'impiego di energia solare. Criteri di ottimizzazione progettuale nelle applicazioni in area Mediterranea

Second Generation of Freescoo Solar DEC Prototypes for Residential Applications

Freescoo is an innovative all-in-one compact solar Desiccant Evaporative Cooling (DEC) air conditioner concept. Results of the first prototype developed were presented at SHC Conference last year. Now a second generation of freescoo prototypes for applications in residential and small office buildings have been installed in Italy at ENEA Casaccia and at UNIPA. The thermodynamic cycle is based on the use of fixed and cooled adsorption beds and advanced evaporative cooling concepts. The adsorption bed, which is a fin and tube heat exchanger packed with silica gel grains, allows simultaneous dehumidification and cooling of the process air. The indirect evaporative cooling process, operated dow…

ENERGY AND ECONOMIC ASSESSMENT OF A SOLAR ABSORPTION REFRIGERATION PLANT IN A FISH PROCESSING FACTORY: A CASE STUDY IN SICILY

Numerical evaluation on performances of AHU equipped with a cross flow heat exchanger in wet and dry operation

Abstract In this paper the comparison between the performance of a cross flow heat exchanger in wet and dry operation for air handling process has been investigated. In addition, a case study of application of the component to perform indirect evaporative cooling in a AHU was studied with the software TRNSYS.Using experimental data and an appropriate analytical method, energy saving performances of the system has been evaluated through the entire cooling season for a typical Mediterranean site. Results show that high energy saving potential can be obtained if the component is operated in wet operation in term of reduction of electricity consumption.

VALUTAZIONI ENERGETICHE ED ECONOMICHE RELATIVE ALL’UTILIZZO DI UN SISTEMA FRIGORIFERO AD ASSORBIMENTO ALIMENTATO DA COLLETTORI PARABOLICI IN SOSTITUZIONE DI UN SISTEMA FRIGORIFERO CONVENZIONALE A COMPRESSIONE DI VAPORE

Monitoring Program of Small-Scale Solar Heating and Cooling within IEA-SHC Task 38 – Procedure and First Results

Within IEA-SHC Task 38 (Solar Air Conditioning and Refrigeration), a monitoring procedure for solar heating and cooling systems was developed. This methodology includes measurements of all relevant energy flows (heat, cold, electricity) to be able to derive key figures such as primary energy ratio, electrical coefficient of performance, solar heat management efficiency, fractional savings for heating and cooling compared to a conventional (non solar) heating and cooling system. A number of small-scale systems for solar heating and cooling are currently being monitored across Europe. For a handful of systems monitoring data of at least a full year of operation is already available. These sys…

Desiccant cooling simulation and design in Matlab/Simlink environment: implementation and validation of the model

Energy performance improvements of a DEC system due to wet heat exchangers

This work concerns an innovative desiccant and evaporative cooling (DEC) system for building air conditioning. The original system is an experimental DEC air handling unit installed at the Solar Laboratory of the University of Palermo and recently modified and updated. With the aim to increase the cooling effect due to water evaporation in the return air flow rate, the sensible heat exchanger was replaced with two cross flow flat plate heat exchangers installed in series, with continuous humidification of the secondary air flow. The new thermodynamic cycle is theoretically described and the realization of the real application is shown. Detailed operational data and energy performance indica…

NEW DEC OPEN CYCLE FOR AIR CONDITIONING BASED ON FIXED COOLED ADSORPTION BEDS AND WET HEAT EXCHANGERS

In this work, a new solar Desiccant Evaporative Cooling (DEC) concept is presented. In the proposed system, two fixed packed desiccant beds of silica gel, operating in a batch process, are used as an alternative solution to the common adsorption rotor for dehumidifying outside air. As well known, adsorption heat due to water condensation considerably reduces the dehumidification capacity of the desiccant material, causing inefficiencies in performance. The aim of the work is to overcome the mentioned intrinsic thermodynamic limit of the adsorption rotor technology. The proposed core component is a fin and tube heat exchanger, commonly used in several air conditioning applications, wherein t…

Solar Cooling

Monitoring of a solar desiccant cooling system in Palermo (italy). First results and test planning

Monitoring and energy performance assessment of an advanced DEC HVAC system in Morocco

This work addresses the energy performance of a solar Desiccant and Evaporative Cooling (DEC) system working with the freescoo technology. Freescoo is an innovative solar air conditioning concept for ventilation, cooling, dehumidification and heating of buildings in residential and tertiary sectors. The monitoring of the system started in November 2016 and will continue until the end of 2017. Energy performances are evaluated according to the monitoring procedure for solar cooling systems developed by the Task 38 and 48 of the International Energy Agency experts. The analysis based on monitoring data shows that, for typical operating conditions in cooling mode, the electricity saving in com…

Life Cycle Assessment of a compact Desiccant Evaporative Cooling system: The case study of the “Freescoo”

Abstract The paper aims at exploring the performances of a compact Desiccant Evaporative Cooling system called “Freescoo” (Free Solar Cooling) in comparison to standard conventional technologies. The Freescoo – that aims at applications in the residential sector and in small office buildings and includes a photovoltaic–thermal system – is analyzed, its monitored performance discussed and reported: under cooling conditions an Energy Efficiency Ratio of 12.8 is calculated, that reaches 50.7 if also photovoltaic generation is considered. To assess the performance of the proposed system a Life Cycle Assessment study was performed to investigate the system covering all its life, from the product…

Experimental results on adsorption beds for air dehumidification

Desiccant rotors are commonly used in large scale solar cooling open cycle applications. As is well known, adsorption heat sensibly reduces the dehumidification capacity of the desiccant material and results in lower system performance. The aim of this work is to describe an innovative solution that permits simultaneous mass and heat transfer. In particular, two components working with silica gel fixed beds were studied and compared. The first component is a simple packed bed containing silica gel grains. The second component is a fin and tube heat exchanger commonly used in several air conditioning applications wherein the spaces between the fins are filled with silica gel grains. In this …

UN IMPIANTO SOLAR DESICCANT COOLING A PALERMO. PROGRAMMA DI RICERCA E PRIMI RISULTATI SPERIMENTALI

Comparative results of monitored solar assisted heating and cooling installations

Monitoring Results and Energy Performances Evaluation of Freescoo Solar DEC Systems

Abstract This work addresses the energy saving performances of some solar Desiccant and Evaporative Cooling (DEC) systems working with the freescoo technology. The innovative freescoo concept is based on the use two fixed and cooled adsorption beds and advanced indirect evaporative cooling processes. The main feature of this new adsorption bed concept is to allow the simultaneous dehumidification and cooling of air. The systems analyzed have been installed in Italy last here and results based on field monitoring data are here presented. A description of the monitored systems and comparisons between the energy performances based on the main performance indicators such as EER, thermal COP, co…

Energy performance evaluation of a demo solar desiccant cooling system with heat recovery for the regeneration of the adsorption material

Abstract Since July 2008, a Solar Desiccant Evaporative Cooling (DEC) system has been operating as a test plant at the solar laboratory of the Dipartimento di Energia (ex DREAM) of the University of Palermo. The system is composed of an air handling unit (AHU) designed for ventilation of the laboratory coupled with a radiant ceiling that provides most of the required sensible cooling/heating energy. Flat plate collectors deliver part of the regeneration heat of the desiccant wheel during the summertime and are used for space heating during the wintertime. The system was designed for high humidity loads because of the typical climate conditions at the site and the need to support a radiant c…

FREESCOO facade 3.0, a compact DEC thermally driven air-conditioning system for apartments

FREESCOO is an innovative Desiccant Evaporative Cooling air conditioning system designed for ventilation, cooling, dehumidification and heating of buildings in residential and tertiary sectors. This paper presents the third generation of the façade version, which will be tested on field in Milan (Italy) within the Merezzate+ project supported by Climate-KIC. The adsorption bed used by the system is a finned heat exchanger packed with silica gel grains, which allows simultaneous dehumidification and cooling of the process air. The direct evaporative cooling process, operated downstream to the dehumidification, is realized using a rotary plate humidifier. The regeneration of the adsorption be…

Experimental results on a solar desiccant and evaporative cooling system equipped with wet heat exchangers

An innovative solar assisted desiccant and evaporative cooling (DEC) system for building air conditioning has been installed at the Solar Laboratory of the University of Palermo. In this system, air-to-air packaged wet heat exchangers are used to maximise the exploitation of the evaporative cooling potential associated with the exhaust air stream. Results obtained are very positive, showing that DEC systems can benefit from the use of wet heat exchangers to efficiently cool the air stream after the adsorption process in the desiccant wheel, without any change in moisture content

Computer model and simulation of a traditional passive cooling ventilation system in a Modern building in Mazara del Vallo (Italy)

Traditional and modern natural ventilation techniques have been integrated in a hybrid system for a retrofitting of public building in the city of Mazara del Vallo (Italy). The hybrid ventilation and air cooling system integrates a wind tower, an indirect evaporative heat exchanger, a ground cooling pipe network and ventilated façade. The first idea was to design a passive cooling system inspired to the typical wind towers of the Middle East, being the area very well ventilated. On the other hand, air humidity in summer is quite high and therefore the effectiveness of indirect evaporative cooling is quite low. For this reason, it was adopted a second passive cooling system consisting in a g…

Method for size optimisation of large wind–hydrogen systems with high penetration on power grids

Wind power generation is growing rapidly in many locations around the world. Power systems are able to absorb large amounts of wind capacity, but operational problems arise when the wind power penetration becomes high. Such factors as voltage dips, frequency variations, low power system stability, low reactive power and power flow imbalances reduce the economic value and represent a barrier to the unlimited development of wind energy. Hydrogen production from wind power that is not matched with hourly electricity demand appears to be an attractive storage option capable of providing a balancing service to the electricity generators and suppliers for mitigation of the negative impacts due to…

Odesse: A New Tool for Simulation and Design of Solar Desiccant Cooling Systems in Energy Efficient Buildings

Analysis of some renewable energy uses and demand side measures for hotels on small Mediterranean islands: A case study

Abstract Tourist activity strongly influences the energy consumption and the overall load profile of communities with isolated energy systems. One example is hotel sectors on small islands that are not connected to mainland energy distribution grids. The use of solar energy systems could be a smart option for reducing energy consumption and tackling seasonal fluctuation. The operation of a weak and isolated electric grid requires attention to the management of power profiles in very short time frames. Energy storage (thermal or electric), as well as building automation control technologies, can be utilised for these aims. In this context, the present paper illustrates a study conducted at a…

ADVANCED SOLAR ASSISTED DESICCANT AND EVAPORATIVE COOLING SYSTEM EQUIPPED WITH WET HEAT EXCHANGERS

Abstract This work concerns an innovative solar assisted desiccant and evaporative cooling (DEC) system for building air conditioning. In this system, air-to-air packaged wet heat exchangers are used to maximize the exploitation of the evaporative cooling potential associated with the exhaust air stream. The thermodynamic cycle is first theoretically described, and then an example of a real application is shown. The system presented is an experimental DEC system originally installed at the beginning of 2008 at the Solar Laboratory of the University of Palermo and recently modified and updated. These modifications have been implemented with the aim to foster some problems related to the conv…

"L'utilizzo dell'energia solare nel riscaldamento e nel raffrescamento degli edifici"

Experimental investigation of adsorption performances of an heat exchanger packed with silica gel for application in solar desiccant systems

DISPOSITIVO E METODO PER IL CONDIZIONAMENTO DELL’ARIA

Solare per la conservazione alimentare

Analisi numerica di un sistema integrato di ventilazione naturale e raffrescamento passivo

Nel presente lavoro viene presentata ed analizzata una soluzione progettuale per la riqualificazione del Municipio di Mazara del Vallo (Italia) che prevede l’impiego di un sistema integrato di ventilazione naturale e raffrescamento passivo. Il sistema in oggetto combina tecniche tradizionali e moderne di ventilazione e raffrescamento ed è costituito da una torre del vento, da una rete di tubazioni interrate, da una facciata ventilata ed da un camino solare. L’intero sistema è stato progettato in modo tale da ottenere la portata di ventilazione utilizzando la torre del vento ed il camino solare rispettivamente per l’immissione e l’estrazione dell’aria. Il comportamento termico dell’edificio …

Life Cycle Assessment (LCA) of solar cooling systems with 12 kW absorption and 8 kW adsorption chillers

Monitoraggio di un impianto solar desiccant cooling a Palermo. primi risultati e progetto dei test

Life cycle performance assessment of small solar thermal cooling systems and conventional plants assisted with photovoltaics

Starting from the results of a Life Cycle Assessment of small solar assisted heat driven chillers, the application of such methodology has been extended to systems with a conventional compression chiller assisted by a photovoltaic plant (PV). This study aims to provide a comprehensive compared investigation of these two families of solar assisted cooling systems (with solar thermal or PV). Results indicate that, in many cases, the systems with the PV grid connected plant performed best. In addition, two more configurations were investigated to further define the PV assisted systems, which minimise their interaction with the grid through the use of electricity storages. These systems performed…

Life Cycle Assessment Performance Comparison of Small Solar Thermal Cooling Systems with Conventional Plants Assisted with Photovoltaics

Abstract Life Cycle Assessment (LCA) allows for the consideration of energy consumption and environmental impacts associated with all the stages of a product's life, from the cradle to the grave . Starting from the results obtained in the IEA SHC Task 38 framework for the LCA of small solar assisted heat driven chillers, the application of such methodology has been extended to systems with a conventional compression chiller assisted by a photovoltaic plant. This study aims to provide a more comprehensive investigation through a comparison of these two families of solar assisted cooling systems (with solar thermal or PV), which is an important topic for studies concerning the research of eff…

Analisi comparata di sistemi solari per il condizionamento tramite la metodologia LCA

Lo studio mostra un'applicazione della metodologia Life Cycle Assessment finalizzata alla valutazione delle prestazioni energetico-ambientali di due differenti tipologie di sistemi di raffrescamento che utilizzano energia solare per applicazioni nel settore civili d'utenza. In dettaglio, sono analizzati sistemi energetici basati su macchine frigorifere convenzionali connesse a impianti fotovoltaici e sistemi di solar cooling alimentati da fluidi a bassa temperatura. I risultati evidenziano che le prestazioni energetico-ambientali dei sistemi connessi alla rete sono superiori a quelle degli altri sistemi, mentre la produzione dei sistemi di accumulo limita la competitività dei sistemi stand-…

Optimisation of Solar Desiccant Cooling Systems for applications in the Mediterranean Climate: design and control issues

Energy and economic assessment of desiccant cooling systems coupled with single glazed air and hybrid PV/thermal solar collectors for applications in hot and humid climate

Abstract This paper presents a detailed analysis of the energy and economic performance of desiccant cooling systems (DEC) equipped with both single glazed standard air and hybrid photovoltaic/thermal (PV/t) collectors for applications in hot and humid climates. The use of ‘solar cogeneration’ by means of PV/t hybrid collectors enables the simultaneous production of electricity and heat, which can be directly used by desiccant air handling units, thereby making it possible to achieve very energy savings. The present work shows the results of detailed simulations conducted for a set of desiccant cooling systems operating without any heat storage. System performance was investigated through h…

Energy performances and life cycle assessment of advanced solar DEC Freescoo units

Freescoo is a new all-in-one compact solar Desiccant Evaporative Cooling (DEC) air conditioner concept. The cooling process is based on the use of fixed and cooled adsorption beds and advanced evaporative cooling concepts. This solution permits to increase the energy performances of the whole cooling process in comparison to the standard desiccant rotor bases DEC cycles. The indirect evaporative cooling process is realized using optimized wet plate heat exchangers which allow low supply temperatures to the room and overall energy performances. The experimental results of an optimized configuration of the freescoo unit together with the Life Cycle Assessment of the unit are here presented an…

Solar desiccant cooling systems with hybrid air-pv solar collectors for applications in the mediterranean climate

VALUTAZIONI ENERGETICHE ED ECONOMICHE RELATIVE ALL’UTILIZZO DI UN SISTEMA DI REFRIGERAZIONE AD ASSORBIMENTO ALIMENTATO DA COLLETTORI PARABOLICI

Studio e progettazione di un sistema di smaltimento statico del calore

Nell’ambito di questa attività sono stati svolti lo studio e la progettazione di un sistema di smaltimento statico del calore da adottare in accoppiamento con sistemi solari termici per evitare il rischio di stagnazione dovuto al mancato utilizzo dell’energia termica prodotta (bassa richiesta di energia termica, assenza dell’alimentazione elettrica). I componenti idraulici comunemente installati negli impianti solari ovvero vaso di espansione, valvole di sicurezza, sfiati e valvole di scarico termico garantiscono l’incolumità degli utilizzatori dai possibili problemi che nascono dall’aumento incontrollato di pressione e temperatura all’interno dell’impianto, ma possono portare ad un parzial…

Task 38 Solar Air-Conditioning and Refrigeration “Life Cycle Assessment of Solar Cooling Systems” A technical report of subtask D Subtask Activity D3

Renewable energy (RE) systems can certainly allow reducing the use of fossil fuels and the related environmental impacts for building air-conditioning. It is more and more clear that good design of the system and appropriateness of the technology are a key issues on the way to maximise the benefits. Therefore, for systems dealing with solar thermal systems, it has been experienced that wrong choices among RE technologies to meet specific applications could also lead to negative effects in terms of Primary Energy (PE) saving.