In this paper a novel dynamic energy performance simulation model for the Phase Change Materials ... more In this paper a novel dynamic energy performance simulation model for the Phase Change Materials (PCM) analysis is presented. The model is implemented in a suitable computer code, written in MatLab and called DETECt, for complete building energy analyses. In the presented model, the “effective specific heat” method is implemented. Here, the specific heat of each PCM layer changes as a function of the system phase and temperature in both melting and freezing processes. A model validation is carried out by comparing numerical results vs. measurements obtained at Solar Laboratory of Concordia University (Montreal, Canada). The simulation model allows exploring the potential of PCMs to increase the thermal inertia of building envelopes and to assess the effects/ weight of several design parameters (e.g. PCMs melting temperature, etc.) on the building heating and cooling energy demand and on the related thermal comfort. In order to show the potentiality of the presented simulation model,...
The efficiency of ventilation and evaporative cooling systems usually depend on the system config... more The efficiency of ventilation and evaporative cooling systems usually depend on the system configuration, air distribution and cattle layout. From a thermo-fluid dynamics point of view, local recirculation zones could be present, reducing significantly the advantages of evaporative cooling. Furthermore, while for hot and dry climates such advantages are in general quite evident, in Italy the temperate and moderately humid summers make uncertain the cost-benefits ratio. Previous results show that such systems are convenient even for temperate climates. In order to get an efficient implementation an optimal location of EC panels is required. From this point of view a double target is required: i) to reduce the indoor dry bulb temperature; ii) to keep low the increasing humidity due to the direct evaporative cooling effect.
ABSTRACT Nowadays the Computational Fluid Dynamics (CFD) simulation represents an important tool ... more ABSTRACT Nowadays the Computational Fluid Dynamics (CFD) simulation represents an important tool for the performance analysis of the Local Exhaust Ventilation (LEV) systems. In this paper the air velocity field in proximity of a freestanding flanged slot and a circular opening is investigated by such approach. The numerically calculated velocities both in centreline and off the hoods axes are compared with the velocities obtained by the most popular experimental and theoretical formulas available in literature. Simple suggested equations with a common mathematical structure are provided for all the numerically simulated velocity trends.
Nowadays in the European framework the good practices for high-performing buildings realization a... more Nowadays in the European framework the good practices for high-performing buildings realization and retrofitting are copious, but what emerges is the lack of information and data sharing about them. There are indeed no official sources for notes deriving from this kind of buildings and, moreover, there is shortage of quantitative and comparable data. In a process oriented to a large-scale diffusion of nZEBs on the market, the existing good practices of actual case studies of highperforming buildings should be kept as market benchmarks and reveal to be precious sources of information. In the light of the above, the need of a harmonized database to collect and share data deriving from different building typologies and climatic zones plays a fundamental role. Due to the weakness of the existing databases and to the necessity of having practical guidelines to design nZEBs, at Italian level, an AiCARR teamwork is targeting the development of a design guide for nZEBs in Mediterranean regi...
The Canary Islands have great potential for the implementation of sustainable energy systems due ... more The Canary Islands have great potential for the implementation of sustainable energy systems due to its availability of natural resources. The archipelago is not connected to the mainland electricity grid and the current generation system is mainly based on traditional fossil fuel. Therefore, the islands strongly dependent on fuel importations, with high costs due to logistics. Furthermore, due to the inadequate coverage of residential heating and cooling needs, the per capita energy consumption is far below the Spanish national average. This occurrence has inspired an intense debate on the current development model of the Canary Archipelago, which has led to the implementation of actions and measures aimed at achieving greater energy sustainability in the archipelago. Furthermore, at a local scale, an important investment plan has been carried out by the Spanish grid operator to ensure energy supply, to improve the system security and reliability, and to optimize the integration of...
Worldwide, the design, renovation, and sustainable management of port buildings play a crucial ro... more Worldwide, the design, renovation, and sustainable management of port buildings play a crucial role for sustainability. In this framework, a computer simulation of a building’s thermal behaviour is an almost mandatory tool for making informed decisions. However, the development of a building energy model is a challenging task that could discourage its adoption. A possible solution would be to exploit an existing Building Information Modeling (BIM) model to automatically generate an accurate and flexible Building Energy Modeling (BEM) one. Such a method, which can substantially improve decision-making processes, still presents some issues and needs to be further investigated, as also detectable from the literature on the topic. In this framework, a novel workflow to extrapolate BIM data for energy simulation is proposed and analysed in this paper. Here, the BIM to BEM approach was tested as a useful tool for the maritime industry to improve the implementation of effective energy-savi...
IOP Conference Series: Materials Science and Engineering
This paper focuses on a novel energy management approach for cluster of buildings connected in mi... more This paper focuses on a novel energy management approach for cluster of buildings connected in micro-grids by taking advantages from plug-in electric vehicles considered as vector devices for renewable energy exchanges, besides additional high-power appliances and house electricity sources. Such approach allows accelerating the development of nearly zero energy buildings and promoting the deployment of renewable energy sources at a micro grid level. To this aim, a dynamic simulation model, implemented in MatLab was developed for the building energy demands and loads assessment. To show the potentiality of the considered concept and approach, a case study based on a micro-grid consisting of a house and an office building connected by an electric vehicle is presented. The optimization of three different layouts, where electricity is alternatively produced by tilted roof or vertical façade photovoltaic panels is conducted by means of a parametric analysis performed by varying the vehic...
Abstract This paper focuses on the design of an innovative low-cost air-based photovoltaic/therma... more Abstract This paper focuses on the design of an innovative low-cost air-based photovoltaic/thermal collector prototype, for which a novel dynamic simulation model is suitably developed in order to investigate its energy performance and economic feasibility under different operating conditions. The main novelty of this photovoltaic/thermal collector is the low-cost heat extraction system, implemented to reduce the photovoltaic cells temperature and to recover thermal energy. The prototype is tested under different operating conditions and the experimental data are used to validate the presented simulation model. The developed tool, implemented in a MatLab code, is used for analysing a suitable case study. The photovoltaic/thermal collectors are coupled to an air-to-air heat pump for space heating of a sample building. A novel performance map of such a coupled system is built with the aim of linking the heat pump coefficient of performance to both the outdoor air temperature and incident solar radiation. In addition, the system energy effectiveness and economic feasibility, compared to those of a traditional system, are assessed for the climate of 8 different European weather zones. Simulation results highlight the effectiveness of the proposed system, estimating primary energy savings (11.0–19.7 MWh/year corresponding to 52–80%), avoided carbon dioxide emissions (4.64–10.4 tCO2/year), and simple pay-back periods (3.2–4.8 years).
Journal of Sustainable Development of Energy, Water and Environment Systems
Phase change materials are considered a very promising technology to reduce energy consumption fo... more Phase change materials are considered a very promising technology to reduce energy consumption for space heating and cooling purposes in buildings. In this framework, this paper presents a comprehensive energy performance analysis of building envelopes integrating phase change materials to provide suitable selection and design criteria of such technology. To this aim, an in-house dynamic simulation model implemented in a computer code, and validated by means of experimental data, has been used. The performance of phase change materials embedded in building enclosures and their optimal configuration (i.e., positions with respect to the construction layers) are evaluated. The results obtained by applying the code to suitable case studies (several climate zones and buildings are investigated) return that the energy saving percentage potentials per cubic meter of phase change materials range from 1.9%/m 3 to 18.8%/ m 3. Finally, interesting design criteria for their adoption in buildings are provided.
Natural gas is typically transported for long distances through high pressure pipelines. Such pre... more Natural gas is typically transported for long distances through high pressure pipelines. Such pressure must be reduced before the gas distribution to users. The natural gas lamination process, traditionally adopted for this scope, may determine hydrate formation which may damagingly affect the system operation. Therefore, in order to avoid such circumstance, a suitable gas preheating is required. On the other hand, the available pressure drop can be recovered through a turbo-expansion system in order to provide mechanical energy to drive electricity generators. In this case a higher gas preheating is necessary. This paper presents a detailed simulation model capable to accurately analyse this process as well as the traditional decompression one. Such new model, implemented in a computer tool written in MATLAB, allows one to dynamically assess the energy, economic and environmental performance of these systems, by also taking into account hourly energy prices and weather conditions. ...
Solar heating and cooling systems are a promising technology which may significantly contribute t... more Solar heating and cooling systems are a promising technology which may significantly contribute to the reduction of greenhouse gas emissions, the enhancement of energy efficiency, and the increase of renewables share in the building sector. The available literature show a high number of papers aiming at investigating solar heating and cooling systems based on heat driven and solar technologies, configurations, operating strategies, and financing issues. Nevertheless, none of the papers available in literature investigates the possibility to replace conventional solar thermal collectors by flat plat and concentrating photovoltaic/thermal systems, also producing renewable electricity. To cover this lack of knowledge, in this paper a dynamic simulation model of novel solar polygeneration heating and cooling systems is presented. Such dynamic simulation model is developed and implemented in a computer code, written in MatLab, and allows investigating the energy, economic and environmental performance of such novel solar polygeneration systems, based on both adsorption and absorption chiller technologies fed by dish-shaped concentrating and flat photovoltaic/thermal collectors. In order to show the potentiality of the presented tool, a comprehensive parametric case study is carried out to find out the optimal system configurations, as a function of crucial design and operating parameters and of weather conditions. The presented case study analysis refers to a small cluster of four buildings, including office and residential spaces, located in different European weather zones. The modelled solar polygeneration systems simultaneously produce electricity, space heating and cooling, and domestic hot water; electricity is self-consumed or delivered to the electrical grid. For comparative purposes, two different backup system configurations, based on an electric chiller and a condensing gas-fired heater are also taken into account as conventional reference building-plant systems. By means of this systematic parametric analysis, comprehensive guidelines for system designers, practitioners and/or researchers focused on the development and use of solar heating and cooling systems are provided.
ABSTRACT In this paper a purposely designed model for the WLHP system analysis is presented. Hour... more ABSTRACT In this paper a purposely designed model for the WLHP system analysis is presented. Hourly, daily and seasonal system performances are computed. A WLHP system performance optimization is carried out varying the system running parameters. In addition comparisons vs. HVAC traditional systems are also assessed. A case study relative to a large commercial building located close to Naples (South Italy) is finally presented. Here encouraging results from both energetic economic and environmental point of view are achieved vs. the traditional systems.
ABSTRACT The paper is focused on the dynamic simulation of a high-temperature Solar Heating and C... more ABSTRACT The paper is focused on the dynamic simulation of a high-temperature Solar Heating and Cooling (SHC) system based on the coupling of Concentrating Photovoltaic/Thermal collectors (CPVT) with a double-effect absorption chiller. The CPVT, made-up by a parabolic dish concentrator and a triple-junction PV receiver, was simulated by means of a zero-dimensional model, already described in Part I. Here, the CPVT model was integrated with the dynamic model of a solar trigeneration system, previously developed by the authors. The polygeneration system under analysis produces electric energy, space heating and domestic hot water for a building, whose simulation is also included in the model. The electric energy is consumed in part consumed by the building (lights, equipments), in part by the system parasitic loads; eventual excess is sold to the public grid. In addition, the CPVT provides the heat required to drive the absorption chiller, which is therefore able to provide also space cooling for the building. A case study is presented and discussed, and the results show that the system under investigation can be economically profitable, provided that an effective funding policy is available.
Abstract Several new technologies can be today implemented in buildings in order to achieve the N... more Abstract Several new technologies can be today implemented in buildings in order to achieve the NZEB goal. In this paper a novel computer model for predicting the energy demand of buildings integrating phase change materials, photovoltaic-thermal collectors, adjacent sunspaces and innovative daylighting control is presented. Through this tool, DETECt 2.2, written in MatLab and conceived for research purposes, the overall energy and economic performance of multi-zone NZEBs can be assessed. Both the active and passive effects on the energy demands of all the above mentioned technologies, even if simultaneously utilized, are taken into account by means of an integrated building modelling approach. In addition, parametric and sensitivity analyses, with a single simulation run, can be carried out for design purposes. A novel relevant case study referred to the energy design of a non-residential NZEB for Mediterranean climates is developed. For this building a suitable energy optimization analysis was also carried out. For each use of the indoor space, the optimal value of the pivotal design and operating parameters is calculated. Details about the optimal position of building PCMs and thermal insulation layers, also coupled to BIPV and/or BIPV/T systems, are provided. For the obtained best configuration very low heating and cooling demands are achieved (0.9 and 1.5 kWh/m 3 y, respectively). Results about a simplified economic analysis carried out on the investigated energy saving technologies are also reported. At last, new NZEB definition details and criteria are provided for non-residential buildings located in the southern European zones (Mediterranean climates).
ABSTRACT In this paper a purposely designed model for the WLHP systems performance analysis is pr... more ABSTRACT In this paper a purposely designed model for the WLHP systems performance analysis is presented. Hourly, daily and seasonal energy system consumption, economic cost and environmental impact are computed. Comparisons vs. HVAC traditional systems are also assessed. Some cases studies relative to installations in two kinds of mall shopping buildings located in different European climatic areas are finally presented. Results are achieved in relation to TRY weather data. Design guidelines could be extracted from the presented investigation. Here, WLHP systems primary energy savings and the avoided CO2 vs. the traditional systems ranges, in function of the considered climatic region, averagely from 0 to 20% and from 0 to 40% respectively. The economic convenience is influenced by the energy national costs ranging from 0 to 25%. Keywords: WLHP system, HVAC performance simulation, building energy saving.
This paper presents experimental and numerical analyses of a novel high-temperature solar cooling... more This paper presents experimental and numerical analyses of a novel high-temperature solar cooling system based on innovative flat-plate evacuated solar thermal collectors (SC). This is the first solar cooling system, including a double-effect absorption chiller, which is based on non-concentrating solar thermal collectors. The aim of the paper is prove the technical and economic feasibility of the system, also presenting a comparison with a conventional technology, based on concentrating solar thermal collectors. To this scope, an experimental setup has been installed in Saudi Arabia. Here, several measurement devices are installed in order to monitor and control all the thermodynamic parameters of the system. The paper presents some of the main results of this experimental campaign, showing temperatures, powers , energies and efficiencies for a selected period. Experimental results showed that collector peak efficiency is higher than 60%, whereas daily average efficiency is around 40%. This prototypal solar cooling system has been numerically analysed, developing a dynamic simulation model aiming at predicting system performance. For a representative operating period, numerical data were compared with the experimental one, showing an excellent accuracy of the model. A similar system, equipped with Parabolic Trough solar thermal collectors (PTC) was also simulated in order to compare the novel solar collectors with such reference technology. For both systems a detailed thermo-economic model has been implemented in order to perform such comparison also from the economic point of view. Results showed that the rated energy performance of the prototypal solar cooling system featuring new collectors is better than that of the reference system. In particular, the difference between the novel and the reference solar cooling system becomes more and more significant, when considering the effects of dust and defocusing related to the tracking mechanism of concentrating collectors in harsh environments. Finally, from the economic point of view, results showed that the novel prototype was able to achieve a good profitability.
This work focuses on a dynamic simulation model for the energy, economic and environmental analys... more This work focuses on a dynamic simulation model for the energy, economic and environmental analysis of an innovative polygenerative system layout based on a building integrated photovoltaic thermal system coupled to an adsorption chiller and to an electricity storage system. The thermal energy of building integrated photovoltaic thermal collectors is exploited in order to produce solar space heating and cooling and domestic hot water. Auxiliary electric air-to-water heat pumps/chillers and a gas-fired condensation boiler are included in the system model in order to integrate the demands of heating, cooling and domestic hot water production. The electricity produced by building integrated photovoltaic thermal collectors is used to satisfy the building needs. The eventual extra-production is delivered to the grid or stored in lead-acid batteries. By means of the developed dynamic simulation model (implemented in TRNSYS environment) the energy system performance on the whole building can be analysed in terms of heating /cooling energy, electricity and domestic hot water demands. In particular, both the passive and active energy effects of the investigated collectors can be assessed. The model includes a suitable tool for the comparison of the innovative system layout vs. traditional reference building-plant systems. For energy, economic and environmental impact optimization purposes, sensitivity analyses can be performed by varying the main system design parameters with respect to the value of reference case ones. In order to show the potentiality of the developed simulation model, several new case studies are developed. They refer to a 3-floor office building located in four different Italian weather zones. Simulation results show that the obtained SPBs, the primary energy saving for electricity and domestic hot water production, and the equivalent carbon dioxide avoided emissions range between 10.6 to 11.3 years, 58.5 to 68.8% and 76.3 to 90.2%, respectively.
In this paper a novel dynamic energy performance simulation model for the Phase Change Materials ... more In this paper a novel dynamic energy performance simulation model for the Phase Change Materials (PCM) analysis is presented. The model is implemented in a suitable computer code, written in MatLab and called DETECt, for complete building energy analyses. In the presented model, the “effective specific heat” method is implemented. Here, the specific heat of each PCM layer changes as a function of the system phase and temperature in both melting and freezing processes. A model validation is carried out by comparing numerical results vs. measurements obtained at Solar Laboratory of Concordia University (Montreal, Canada). The simulation model allows exploring the potential of PCMs to increase the thermal inertia of building envelopes and to assess the effects/weight of several design parameters (e.g. PCMs melting temperature, etc.) on the building heating and cooling energy demand and on the related thermal comfort. In order to show the potentiality of the presented simulation model, suitable case studies referred to residential and office buildings, to three different weather conditions and to two alternative PCM layouts in the building envelope, are developed.
In this paper a novel dynamic energy performance simulation model for the Phase Change Materials ... more In this paper a novel dynamic energy performance simulation model for the Phase Change Materials (PCM) analysis is presented. The model is implemented in a suitable computer code, written in MatLab and called DETECt, for complete building energy analyses. In the presented model, the “effective specific heat” method is implemented. Here, the specific heat of each PCM layer changes as a function of the system phase and temperature in both melting and freezing processes. A model validation is carried out by comparing numerical results vs. measurements obtained at Solar Laboratory of Concordia University (Montreal, Canada). The simulation model allows exploring the potential of PCMs to increase the thermal inertia of building envelopes and to assess the effects/ weight of several design parameters (e.g. PCMs melting temperature, etc.) on the building heating and cooling energy demand and on the related thermal comfort. In order to show the potentiality of the presented simulation model,...
The efficiency of ventilation and evaporative cooling systems usually depend on the system config... more The efficiency of ventilation and evaporative cooling systems usually depend on the system configuration, air distribution and cattle layout. From a thermo-fluid dynamics point of view, local recirculation zones could be present, reducing significantly the advantages of evaporative cooling. Furthermore, while for hot and dry climates such advantages are in general quite evident, in Italy the temperate and moderately humid summers make uncertain the cost-benefits ratio. Previous results show that such systems are convenient even for temperate climates. In order to get an efficient implementation an optimal location of EC panels is required. From this point of view a double target is required: i) to reduce the indoor dry bulb temperature; ii) to keep low the increasing humidity due to the direct evaporative cooling effect.
ABSTRACT Nowadays the Computational Fluid Dynamics (CFD) simulation represents an important tool ... more ABSTRACT Nowadays the Computational Fluid Dynamics (CFD) simulation represents an important tool for the performance analysis of the Local Exhaust Ventilation (LEV) systems. In this paper the air velocity field in proximity of a freestanding flanged slot and a circular opening is investigated by such approach. The numerically calculated velocities both in centreline and off the hoods axes are compared with the velocities obtained by the most popular experimental and theoretical formulas available in literature. Simple suggested equations with a common mathematical structure are provided for all the numerically simulated velocity trends.
Nowadays in the European framework the good practices for high-performing buildings realization a... more Nowadays in the European framework the good practices for high-performing buildings realization and retrofitting are copious, but what emerges is the lack of information and data sharing about them. There are indeed no official sources for notes deriving from this kind of buildings and, moreover, there is shortage of quantitative and comparable data. In a process oriented to a large-scale diffusion of nZEBs on the market, the existing good practices of actual case studies of highperforming buildings should be kept as market benchmarks and reveal to be precious sources of information. In the light of the above, the need of a harmonized database to collect and share data deriving from different building typologies and climatic zones plays a fundamental role. Due to the weakness of the existing databases and to the necessity of having practical guidelines to design nZEBs, at Italian level, an AiCARR teamwork is targeting the development of a design guide for nZEBs in Mediterranean regi...
The Canary Islands have great potential for the implementation of sustainable energy systems due ... more The Canary Islands have great potential for the implementation of sustainable energy systems due to its availability of natural resources. The archipelago is not connected to the mainland electricity grid and the current generation system is mainly based on traditional fossil fuel. Therefore, the islands strongly dependent on fuel importations, with high costs due to logistics. Furthermore, due to the inadequate coverage of residential heating and cooling needs, the per capita energy consumption is far below the Spanish national average. This occurrence has inspired an intense debate on the current development model of the Canary Archipelago, which has led to the implementation of actions and measures aimed at achieving greater energy sustainability in the archipelago. Furthermore, at a local scale, an important investment plan has been carried out by the Spanish grid operator to ensure energy supply, to improve the system security and reliability, and to optimize the integration of...
Worldwide, the design, renovation, and sustainable management of port buildings play a crucial ro... more Worldwide, the design, renovation, and sustainable management of port buildings play a crucial role for sustainability. In this framework, a computer simulation of a building’s thermal behaviour is an almost mandatory tool for making informed decisions. However, the development of a building energy model is a challenging task that could discourage its adoption. A possible solution would be to exploit an existing Building Information Modeling (BIM) model to automatically generate an accurate and flexible Building Energy Modeling (BEM) one. Such a method, which can substantially improve decision-making processes, still presents some issues and needs to be further investigated, as also detectable from the literature on the topic. In this framework, a novel workflow to extrapolate BIM data for energy simulation is proposed and analysed in this paper. Here, the BIM to BEM approach was tested as a useful tool for the maritime industry to improve the implementation of effective energy-savi...
IOP Conference Series: Materials Science and Engineering
This paper focuses on a novel energy management approach for cluster of buildings connected in mi... more This paper focuses on a novel energy management approach for cluster of buildings connected in micro-grids by taking advantages from plug-in electric vehicles considered as vector devices for renewable energy exchanges, besides additional high-power appliances and house electricity sources. Such approach allows accelerating the development of nearly zero energy buildings and promoting the deployment of renewable energy sources at a micro grid level. To this aim, a dynamic simulation model, implemented in MatLab was developed for the building energy demands and loads assessment. To show the potentiality of the considered concept and approach, a case study based on a micro-grid consisting of a house and an office building connected by an electric vehicle is presented. The optimization of three different layouts, where electricity is alternatively produced by tilted roof or vertical façade photovoltaic panels is conducted by means of a parametric analysis performed by varying the vehic...
Abstract This paper focuses on the design of an innovative low-cost air-based photovoltaic/therma... more Abstract This paper focuses on the design of an innovative low-cost air-based photovoltaic/thermal collector prototype, for which a novel dynamic simulation model is suitably developed in order to investigate its energy performance and economic feasibility under different operating conditions. The main novelty of this photovoltaic/thermal collector is the low-cost heat extraction system, implemented to reduce the photovoltaic cells temperature and to recover thermal energy. The prototype is tested under different operating conditions and the experimental data are used to validate the presented simulation model. The developed tool, implemented in a MatLab code, is used for analysing a suitable case study. The photovoltaic/thermal collectors are coupled to an air-to-air heat pump for space heating of a sample building. A novel performance map of such a coupled system is built with the aim of linking the heat pump coefficient of performance to both the outdoor air temperature and incident solar radiation. In addition, the system energy effectiveness and economic feasibility, compared to those of a traditional system, are assessed for the climate of 8 different European weather zones. Simulation results highlight the effectiveness of the proposed system, estimating primary energy savings (11.0–19.7 MWh/year corresponding to 52–80%), avoided carbon dioxide emissions (4.64–10.4 tCO2/year), and simple pay-back periods (3.2–4.8 years).
Journal of Sustainable Development of Energy, Water and Environment Systems
Phase change materials are considered a very promising technology to reduce energy consumption fo... more Phase change materials are considered a very promising technology to reduce energy consumption for space heating and cooling purposes in buildings. In this framework, this paper presents a comprehensive energy performance analysis of building envelopes integrating phase change materials to provide suitable selection and design criteria of such technology. To this aim, an in-house dynamic simulation model implemented in a computer code, and validated by means of experimental data, has been used. The performance of phase change materials embedded in building enclosures and their optimal configuration (i.e., positions with respect to the construction layers) are evaluated. The results obtained by applying the code to suitable case studies (several climate zones and buildings are investigated) return that the energy saving percentage potentials per cubic meter of phase change materials range from 1.9%/m 3 to 18.8%/ m 3. Finally, interesting design criteria for their adoption in buildings are provided.
Natural gas is typically transported for long distances through high pressure pipelines. Such pre... more Natural gas is typically transported for long distances through high pressure pipelines. Such pressure must be reduced before the gas distribution to users. The natural gas lamination process, traditionally adopted for this scope, may determine hydrate formation which may damagingly affect the system operation. Therefore, in order to avoid such circumstance, a suitable gas preheating is required. On the other hand, the available pressure drop can be recovered through a turbo-expansion system in order to provide mechanical energy to drive electricity generators. In this case a higher gas preheating is necessary. This paper presents a detailed simulation model capable to accurately analyse this process as well as the traditional decompression one. Such new model, implemented in a computer tool written in MATLAB, allows one to dynamically assess the energy, economic and environmental performance of these systems, by also taking into account hourly energy prices and weather conditions. ...
Solar heating and cooling systems are a promising technology which may significantly contribute t... more Solar heating and cooling systems are a promising technology which may significantly contribute to the reduction of greenhouse gas emissions, the enhancement of energy efficiency, and the increase of renewables share in the building sector. The available literature show a high number of papers aiming at investigating solar heating and cooling systems based on heat driven and solar technologies, configurations, operating strategies, and financing issues. Nevertheless, none of the papers available in literature investigates the possibility to replace conventional solar thermal collectors by flat plat and concentrating photovoltaic/thermal systems, also producing renewable electricity. To cover this lack of knowledge, in this paper a dynamic simulation model of novel solar polygeneration heating and cooling systems is presented. Such dynamic simulation model is developed and implemented in a computer code, written in MatLab, and allows investigating the energy, economic and environmental performance of such novel solar polygeneration systems, based on both adsorption and absorption chiller technologies fed by dish-shaped concentrating and flat photovoltaic/thermal collectors. In order to show the potentiality of the presented tool, a comprehensive parametric case study is carried out to find out the optimal system configurations, as a function of crucial design and operating parameters and of weather conditions. The presented case study analysis refers to a small cluster of four buildings, including office and residential spaces, located in different European weather zones. The modelled solar polygeneration systems simultaneously produce electricity, space heating and cooling, and domestic hot water; electricity is self-consumed or delivered to the electrical grid. For comparative purposes, two different backup system configurations, based on an electric chiller and a condensing gas-fired heater are also taken into account as conventional reference building-plant systems. By means of this systematic parametric analysis, comprehensive guidelines for system designers, practitioners and/or researchers focused on the development and use of solar heating and cooling systems are provided.
ABSTRACT In this paper a purposely designed model for the WLHP system analysis is presented. Hour... more ABSTRACT In this paper a purposely designed model for the WLHP system analysis is presented. Hourly, daily and seasonal system performances are computed. A WLHP system performance optimization is carried out varying the system running parameters. In addition comparisons vs. HVAC traditional systems are also assessed. A case study relative to a large commercial building located close to Naples (South Italy) is finally presented. Here encouraging results from both energetic economic and environmental point of view are achieved vs. the traditional systems.
ABSTRACT The paper is focused on the dynamic simulation of a high-temperature Solar Heating and C... more ABSTRACT The paper is focused on the dynamic simulation of a high-temperature Solar Heating and Cooling (SHC) system based on the coupling of Concentrating Photovoltaic/Thermal collectors (CPVT) with a double-effect absorption chiller. The CPVT, made-up by a parabolic dish concentrator and a triple-junction PV receiver, was simulated by means of a zero-dimensional model, already described in Part I. Here, the CPVT model was integrated with the dynamic model of a solar trigeneration system, previously developed by the authors. The polygeneration system under analysis produces electric energy, space heating and domestic hot water for a building, whose simulation is also included in the model. The electric energy is consumed in part consumed by the building (lights, equipments), in part by the system parasitic loads; eventual excess is sold to the public grid. In addition, the CPVT provides the heat required to drive the absorption chiller, which is therefore able to provide also space cooling for the building. A case study is presented and discussed, and the results show that the system under investigation can be economically profitable, provided that an effective funding policy is available.
Abstract Several new technologies can be today implemented in buildings in order to achieve the N... more Abstract Several new technologies can be today implemented in buildings in order to achieve the NZEB goal. In this paper a novel computer model for predicting the energy demand of buildings integrating phase change materials, photovoltaic-thermal collectors, adjacent sunspaces and innovative daylighting control is presented. Through this tool, DETECt 2.2, written in MatLab and conceived for research purposes, the overall energy and economic performance of multi-zone NZEBs can be assessed. Both the active and passive effects on the energy demands of all the above mentioned technologies, even if simultaneously utilized, are taken into account by means of an integrated building modelling approach. In addition, parametric and sensitivity analyses, with a single simulation run, can be carried out for design purposes. A novel relevant case study referred to the energy design of a non-residential NZEB for Mediterranean climates is developed. For this building a suitable energy optimization analysis was also carried out. For each use of the indoor space, the optimal value of the pivotal design and operating parameters is calculated. Details about the optimal position of building PCMs and thermal insulation layers, also coupled to BIPV and/or BIPV/T systems, are provided. For the obtained best configuration very low heating and cooling demands are achieved (0.9 and 1.5 kWh/m 3 y, respectively). Results about a simplified economic analysis carried out on the investigated energy saving technologies are also reported. At last, new NZEB definition details and criteria are provided for non-residential buildings located in the southern European zones (Mediterranean climates).
ABSTRACT In this paper a purposely designed model for the WLHP systems performance analysis is pr... more ABSTRACT In this paper a purposely designed model for the WLHP systems performance analysis is presented. Hourly, daily and seasonal energy system consumption, economic cost and environmental impact are computed. Comparisons vs. HVAC traditional systems are also assessed. Some cases studies relative to installations in two kinds of mall shopping buildings located in different European climatic areas are finally presented. Results are achieved in relation to TRY weather data. Design guidelines could be extracted from the presented investigation. Here, WLHP systems primary energy savings and the avoided CO2 vs. the traditional systems ranges, in function of the considered climatic region, averagely from 0 to 20% and from 0 to 40% respectively. The economic convenience is influenced by the energy national costs ranging from 0 to 25%. Keywords: WLHP system, HVAC performance simulation, building energy saving.
This paper presents experimental and numerical analyses of a novel high-temperature solar cooling... more This paper presents experimental and numerical analyses of a novel high-temperature solar cooling system based on innovative flat-plate evacuated solar thermal collectors (SC). This is the first solar cooling system, including a double-effect absorption chiller, which is based on non-concentrating solar thermal collectors. The aim of the paper is prove the technical and economic feasibility of the system, also presenting a comparison with a conventional technology, based on concentrating solar thermal collectors. To this scope, an experimental setup has been installed in Saudi Arabia. Here, several measurement devices are installed in order to monitor and control all the thermodynamic parameters of the system. The paper presents some of the main results of this experimental campaign, showing temperatures, powers , energies and efficiencies for a selected period. Experimental results showed that collector peak efficiency is higher than 60%, whereas daily average efficiency is around 40%. This prototypal solar cooling system has been numerically analysed, developing a dynamic simulation model aiming at predicting system performance. For a representative operating period, numerical data were compared with the experimental one, showing an excellent accuracy of the model. A similar system, equipped with Parabolic Trough solar thermal collectors (PTC) was also simulated in order to compare the novel solar collectors with such reference technology. For both systems a detailed thermo-economic model has been implemented in order to perform such comparison also from the economic point of view. Results showed that the rated energy performance of the prototypal solar cooling system featuring new collectors is better than that of the reference system. In particular, the difference between the novel and the reference solar cooling system becomes more and more significant, when considering the effects of dust and defocusing related to the tracking mechanism of concentrating collectors in harsh environments. Finally, from the economic point of view, results showed that the novel prototype was able to achieve a good profitability.
This work focuses on a dynamic simulation model for the energy, economic and environmental analys... more This work focuses on a dynamic simulation model for the energy, economic and environmental analysis of an innovative polygenerative system layout based on a building integrated photovoltaic thermal system coupled to an adsorption chiller and to an electricity storage system. The thermal energy of building integrated photovoltaic thermal collectors is exploited in order to produce solar space heating and cooling and domestic hot water. Auxiliary electric air-to-water heat pumps/chillers and a gas-fired condensation boiler are included in the system model in order to integrate the demands of heating, cooling and domestic hot water production. The electricity produced by building integrated photovoltaic thermal collectors is used to satisfy the building needs. The eventual extra-production is delivered to the grid or stored in lead-acid batteries. By means of the developed dynamic simulation model (implemented in TRNSYS environment) the energy system performance on the whole building can be analysed in terms of heating /cooling energy, electricity and domestic hot water demands. In particular, both the passive and active energy effects of the investigated collectors can be assessed. The model includes a suitable tool for the comparison of the innovative system layout vs. traditional reference building-plant systems. For energy, economic and environmental impact optimization purposes, sensitivity analyses can be performed by varying the main system design parameters with respect to the value of reference case ones. In order to show the potentiality of the developed simulation model, several new case studies are developed. They refer to a 3-floor office building located in four different Italian weather zones. Simulation results show that the obtained SPBs, the primary energy saving for electricity and domestic hot water production, and the equivalent carbon dioxide avoided emissions range between 10.6 to 11.3 years, 58.5 to 68.8% and 76.3 to 90.2%, respectively.
In this paper a novel dynamic energy performance simulation model for the Phase Change Materials ... more In this paper a novel dynamic energy performance simulation model for the Phase Change Materials (PCM) analysis is presented. The model is implemented in a suitable computer code, written in MatLab and called DETECt, for complete building energy analyses. In the presented model, the “effective specific heat” method is implemented. Here, the specific heat of each PCM layer changes as a function of the system phase and temperature in both melting and freezing processes. A model validation is carried out by comparing numerical results vs. measurements obtained at Solar Laboratory of Concordia University (Montreal, Canada). The simulation model allows exploring the potential of PCMs to increase the thermal inertia of building envelopes and to assess the effects/weight of several design parameters (e.g. PCMs melting temperature, etc.) on the building heating and cooling energy demand and on the related thermal comfort. In order to show the potentiality of the presented simulation model, suitable case studies referred to residential and office buildings, to three different weather conditions and to two alternative PCM layouts in the building envelope, are developed.
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Papers by Adolfo Palombo
includes a suitable tool for the comparison of the innovative system layout vs. traditional reference building-plant systems. For energy, economic and environmental impact optimization purposes, sensitivity analyses can be performed by varying the main system design parameters with respect to the value of reference case ones.
In order to show the potentiality of the developed simulation model, several new case studies are developed. They refer to a 3-floor office building located in four different Italian weather zones. Simulation results show that the obtained SPBs, the primary energy saving for electricity and domestic hot water production, and the equivalent carbon dioxide avoided emissions range between 10.6 to 11.3 years, 58.5 to 68.8% and 76.3 to 90.2%, respectively.
includes a suitable tool for the comparison of the innovative system layout vs. traditional reference building-plant systems. For energy, economic and environmental impact optimization purposes, sensitivity analyses can be performed by varying the main system design parameters with respect to the value of reference case ones.
In order to show the potentiality of the developed simulation model, several new case studies are developed. They refer to a 3-floor office building located in four different Italian weather zones. Simulation results show that the obtained SPBs, the primary energy saving for electricity and domestic hot water production, and the equivalent carbon dioxide avoided emissions range between 10.6 to 11.3 years, 58.5 to 68.8% and 76.3 to 90.2%, respectively.