Search results for "conditioning system"
showing 7 items of 7 documents
Experimental characterization of variable-speed packaged rooftop units in presence of evaporator fouling
2022
Variable-speed packaged rooftop units have been increasingly adopted in the commercial sector. If not properly maintained, the fouling of heat exchangers and the improper refrigerant charge could increase energy consumption. In this work, the response of variable-speed rooftop units to evaporator fouling is investigated based on experiments on a variable-speed 17.5 kW rooftop unit. A novel testing procedure is proposed, aimed at covering a broad range of operating conditions by a reduced number of tests. Two opposite cases were investigated: (i) even in presence of fouling, the controller can restore the required cooling capacity, and (ii) the intensity of the fouling does not allow the con…
Photovoltaic plant array reconfiguration: Design of a new device
2014
An efficient strategy to improve unequally irradiated PV plants performances is based on the reconfiguration of the connections between the modules. In this paper, an algorithm, for this purpose conceived, is presented. Moreover, the design, realization and finally also the set up of a new reconfiguration system device is fully shown and discussed. The algorithm conceived simulates several possible series-parallel connections under varying irradiation conditions, and determines the optimal modules connection in order to get the maximum output power. In this way, the reconfiguration system may set up the reconfiguration strategy. The reconfiguration system prototype set up, basically consist…
Thermoeconomic Diagnosis of Air conditioning Systems: an Innovative Approach for Improved Reliability of the Technique
2018
Thermoeconomic diagnosis is an exergy-based fault detection and diagnosis technique which has been recently extended to air conditioning systems. One of the main features of this technique is to provide quantitative information of the impact of each fault on the increased energy consumption of a system. This information is then used for programming cost-effective maintenance strategies. Only few papers have focused on it and a lot of work is needed for further improvements. In this work, the approach was developed by means of experimental activities carried out on a 17.5 kW packaged rooftop air conditioning unit (RTU). The RTU was tested in psychrometric chambers under a wide range of opera…
ELISA: A simplified tool for evaluating the Environmental Life-cycle Impacts of Solar Air-conditioning systems
2018
The paper presents ELISA, a simplified tool for estimating the Environmental Life-cycle Impacts of Solar Air-conditioning systems. The tool is designed to support researchers, designers and decision makers in a simplified evaluation of the life cycle energy and environmental potential benefits related to the installation of solar heating and cooling systems in substitution of conventional ones. The tool was developed within the research activities of Task 53 “New Generation Solar Cooling & Heating Systems (PV or solar thermally driven systems)” of the International Energy Agency.
Materiali e Tecniche Innovative per l'Edilizia Sostenibile
2021
Il cambiamento climatico e la necessità di ridurre il consumo energetico degli edifici sono argomenti chiave del dibattito politico, scientifico, economico e culturale. Un dibattito al quale si è voluto dare il proprio contributo sin dall’anno accademico 2010-2011 con la prima edizione del Master in Materiali e Tecniche Innovative per l’Edilizia Sostenibile (MeTIES) dell’Università degli Studi di Palermo insieme al Consorzio Universitario per l’Ateneo della Sicilia Occidentale e del Bacino del Mediterraneo (UNISOM), perseguendo il preciso obiettivo di formare una generazione di professionisti che sappiano padroneggiare le nuove tecnologie per ripensare il modo di “costruire”. Tutti gli stud…
Development of “Design of Experiments” for modelling direct expansion air-conditioning systems under variable cooling loads and faulty operating cond…
2019
Air conditioning systems are widely adopted in the building sector and are generally responsible for high energy consumption. Part of this consumption is related to the poor maintenance adopted by plant owner over time, which causes energy performance degradation. Typical faults, such as fouling or improper refrigerant charge have been shown to heavily impact on energy consumption of these systems. In order to support cost-effective maintenance schedule, Fault Detection and Diagnosis Technique are under investigation in the world. However, in order to devise a diagnostic method a preliminary modelling of air conditioning system is due. To this aim, a test procedure which requires the least …
Electrical hybrid heat pumps assisted by natural gas boilers: a review
2022
In this paper, a comprehensive review is performed on hybrid systems using electrical Heat Pumps for Heating, Ventilation & Air Conditioning systems and Domestic Hot Water production using case studies from 2016 to 2022. This work particularly focuses on studies that investigated systems with electrical Heat Pumps assisted by a gas boiler. Some studies that considered the exploitation of renewable energy sources, but not as a whole sub-stitute for fossil sources, have also been included. In particular, the analysis investigated the layouts of the systems by considering the type and the size of the components, the control methods applied (by distinguishing rule-based control methods and …