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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 and discussed.

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 the spaces between the fins are filled with silica gel grains. Therefore, the adsorption material is cooled through a water loop in connection with a cooling tower. An important feature of the system is the adsorption storage capacity, this is due to the high amount of desiccant material available. An indirect cooling process of the air is then realized by means of two wet evaporative heat exchangers connected in series, with continuous humidification of the secondary side. The thermodynamic cycle is first presented and simulation results are shown and discussed. Possible applications may concern compact roof-top units as well as common AHUs.

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

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 indicators are presented and compared to the previous configuration.

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 è stato analizzato attraverso simulazioni dinamiche svolte con il software TRNSYS utilizzando un modello mono - zona accoppiato ad una facciata ventilata. Per la simulazione della torre del vento è stato invece definito un apposito modello che permette il calcolo della prevalenza sviluppata e della variazione di temperatura subita dalla corrente d’aria di ventilazione. I risultati in termini di risparmio di energia primaria per il raffrescamento e la movimentazione dell’aria rispetto alla soluzione di tipo convenzionale considerata sono interessanti e danno utili suggerimenti per la progettazione di sistemi impiantistici simili.

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 systems include different chiller, heat rejection and collector technologies and are used for different applications (office buildings, canteen, school etc.). Key figures derived from the monitoring data of these systems will be presented in this paper as well as a comparison of the systems with each other.

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 ground heat exchanger which cools down further the air stream. Air exiting form the buried pipes is then drawn into the building. The whole system has been designed in order to achieve the required air-flow rate by natural ventilation using the wind tower. A back-up ventilation system will fulfil for the required air change if the natural ventilation system doesn’t guarantee the specified flow rate. From the thermal point of view, the system was designed, modelled and tested by using a dynamic simulation software (TRNSYS). The building has been simulated with a two-zones model coupled with a natural ventilated façade. The climate of the site as well as the influence of the solar radiation on the building were investigated by means of the software ECOTECT. Results are interesting in terms of energy saving for cooling and air circulation and gives useful hints to refine the design process.