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The paper presents the operation mode of a ventilation chimney placed in a historical building through the use of Design Builder, a modeling and dynamical simulation software. The aim is to verify the improvement of the comfort level and energy efficiency of the simulated environments through the usage of the duct as a passive ventilation system. The method adopted to intervene in a complex system, such as that represented by historic buildings, is to enhance the preexisting architectural values through their conversion into devices able to improve the performance of the building in terms of CO2 and energy consumption reduction. The case study is Palazzo Bruni-Riga, a valuable building located in the historic center of L'Aquila. The building has a double ventilation duct, probably also used as a light-pipe, in correspondence of two windowless rooms of similar dimensions. The dynamical simulations presented concern the analysis of the passive ventilation duct and its effects on the thermo-hygrometric well-being of the modeled rooms. The goal of this paper and this research in general, is that the wise use of such devices installed in times when there were no air conditioning systems, allows you to better use the ventilation chimneys, and have the maximum thermal indoor comfort, with the minimum effort and use of mechanical systems. Through the simulations it was possible to verify that through the use of the ventilation chimney, it is possible to have the indoor comfort conditions, by checking the Fanger indices for the data obtained from the simulations carried out. (C) 2018 The Authors. Published by Elsevier Ltd.

Nowadays, energy conservation in buildings is especially important for countries where high energy consumption in the residential and tertiary sectors causes the high energy intensity of the whole economy. This paper presents some idea of creating energy efficient building envelopes. The focus is on reduction of heat transfer through it. Different structures of external walls are analyzed. In high latitude countries walls should be characterized by high thermal resistance and high thermal capacity (good storage ability). In the paper traditional multilayer wall structures with specific paints on external wall surfaces are analyzed. Paints are characterized by different solar absorptivity. Two extreme cases of solar absorptivity of external wall paints (0.9 for the black paint and 0.1 for the black paint) have been taken into account to give completely different ability of the external wall surface for photo-thermal conversion (of solar radiation). Results show that in moderate or cold climates, if thick thermal insulation is applied as external layer of a building envelope, then the effect of solar absorptivity of a cover paint of external wall surface is not meaningful. In July, when daily solar irradiation is the highest, in the case of the black paint all day long there are small heat gains (about 2 kJ m−2 in average) with maximum in the night (3.1 kJ m−2). In the case of the white paint all day long there are small heat losses (about 2.3 kJ m−2 in average), with maximum in the middle of a day (2.7 kJ m−2). The effect of the solar absorptivity of the paint, that covers the external surface of the wall, can be seen, but it is very small and perhaps cannot be noticed by inhabitants. However, in the extreme summer weather conditions, i.e. very high irradiance level and high ambient air temperature, what have happened quite often in high latitude countries recently, the considered effect is more strong. Therefore, it would be good to apply envelope of a building, that can change “the skin” from summer to winter. Also modern structures with the Phase Change Materials (PCMs) are analyzed. In simulation study it was assumed that PCMs are applied in the form of light thermal mass panels that are integrated with the external wall structure. A mathematical model of dynamics of a building has been developed. In the paper stress has been put on energy transfer through walls of different structures. The model takes into account the influence of solar radiation on energy balance, including the availability of solar radiation on walls of different location (inclination and orientation). On the basis of the model developed simulation studies have been performed. Selected results of thermal behavior of some multilayer structures of external walls of a building have been analyzed. Through comparative studies some recommendations for creating building wall structures have been formulated. Results (presented in figures) show, how the temperature of a wall surface can increase because of the high solar radiation absorptivity of the surface paint. The temperature is especially high when a thick insulation is used. Because of the insulation the heat transfer through the wall is reduced significantly. If there is no insulation than the heat gained can be conducted (relatively easily) through the wall to the interior of a building, in consequence there are high heat gains in summer, and the temperature of the external wall surface is not high. It is evident that external surface temperature is not the basic parameter that determines the real heat transfer through a wall. Results show that in high latitude countries a wall structure for a standard building (used all year around) must contain thermal insulation as external layer. This is also true when the PCMs are applied in the form of light thermal mass panels. For high latitude countries the recommended structure of an external wall is following: thermal insulation (e.g. mineral wool) at outside (external layer) of thickness of 25 cm and PCM thermal mass panel at inside (internal layer) of thickness of 1 cm. Such wall structure assures full reduction of the ambient surrounding influence. An external wall made of a brick and a PCM panel does not have high enough thermal resistance (even if thermal capacity is high) to keep the room temperature at the required level. However, such structure could be recommended for the summer season, e.g. for summer houses in a moderate climate or high latitude countries, or for warm climate.

Lighting systems have a fundamental role for the overall buildings energy consumption. Therefore, remarkable efforts are required for optimizing the lighting systems energy use and for finding new daylight harvesting solutions. In this paper, the impacts on daylight harvesting provided by different room and window geometries and their effects on energy savings are presented. An academic classroom with only one window is chosen as case study and it is supposed that the window orientation is modified according to the four cardinal points. A climate-based approach was chosen for the multiple simulations, carried out via DIVA software, by assuming: square and rectangular classroom geometries with the same total area; square and rectangular window shapes having Window to Floor Ratios (WFRs) equal to 8% and 12%; two different dimmable lighting systems, in order to quantify the energy savings, by considering fluorescent and LED dimmable lamps. The daylight analysis, performed by evaluating both the Daylight Factor (DF) and the Daylight Autonomy (DA), showed that room and window geometries have high influence on daylight harvesting maximization, allowing remarkable energy savings (up to 48.5%) with respect to non-dimmable lighting system. In particular, the best energy result, equal to 467.5 kWh/yr, was obtained with rectangular room and window geometries coupled with LED lamps and WFR equal to 12%.

Data centers are facilities hosting a large number of servers dedicated to data storage and management. In recent years, their power consumption has increased significantly due to the power density of the IT equipment. In particular, cooling represents approximately one third of the total electricity consumption, therefore efficiently cooling data centers has become a challenging problem and it represents an opportunity to reduce both IT energy costs and emissions environmental impact. The efficiency of computers room air conditioning (CRAC) systems can be increased using both advanced control techniques and new free cooling technologies, such as the indirect adiabatic cooling (IAC), that is the humidification of air under adiabatic conditions. Water sprinkled by spray nozzles humidifies and cools down the air taken from the outside, which then cools down the computers room air by means of a crossflow heat exchanger. In this way, the process air temperature is economically reduced and the cooling process is effective even when the outside temperature is warmer than that desired in the computers room. Beside the traditional approach, that improves energy efficiency of CRAC systems through advanced hardware design, nowadays advanced control systems offer the opportunity to improve both efficiency and performance by mostly acting on software components. In particular, a model-based paradigm can result very useful in the design of the controller. This approach involves three main steps: plant modelling, controller design, and simulations. In this paper, First-Principle Data-Driven (FPDD) techniques have been considered in the modelling phase, in order to obtain a model as simple as possible but accurate enough. All the main components of the plant, such as fans, spray nozzles, heat exchanger, and the computers room have been taken into account and they have been calibrated exploiting real data. The dynamics of the computers room variables (e.g. temperature) are slower than those of the components of the cooling system, due to higher thermal inertias of the computers room. Therefore, fans, heat exchanger, and spray nozzles are described by static models, whereas the computers room is described by a LTI dynamic model. Once obtained a model of the plant, a simulation environment based on Matlab/Simulink is designed accordingly. The developed control system is hierarchical: a supervisor determines the best combination of CRAC water and process air flows which minimizes the total power consumption, while satisfying the cooling demand. This system energy management problem is formulated as a non-linear optimization problem, subject to internal air condition requirements and system operating constraints. The optimization problem is repeatedly solved at each supervision period by using a population based stochastic optimization technique (Particle Swarm Optimization). Results of simulations show that the proposed control system is effective and minimizes the input electric power while satisfying both the data center thermal load and system operating constraints.

This paper deals with the potential role of new hybrid CHP systems application providing both electricity and heat which are compatible with the building architectural and landscape limitations. In detail, three different plant layout options for high temperature heat production along with the electricity generation were investigated and compared each other. To do so, conventional natural gas CHPs and back up boiler, two-stage Electric Heat Pumps (EHPs) and trans-critical CO2 electric heat pump (CO2-HP) have been considered as reference technologies to build hybrid systems. In addition, hybrid solar collectors (PV/T) thermal output, along with the recovered low-grade heat from CHP exhaust gas, flowing to the stack, have been used as the CO2-HP low temperature driving source.

This paper presents the ENERSI platform, an energy information system that provides advanced energy services by means of integrating energy related data from multiple domains and formats using Semantic Web technologies. The platform services can provide qualified information at different scales – from building to district, city and region – to different kind of users – such as building owners, city planner, energy agencies, architects, contractors and consultants – to take decisions aimed at improving the building energy performance in their respective decision-making realms.

Energy retrofitting solutions applied in residential building envelopes often consist in adding an insulation layer on the building facade and substituting the old windows with better performing ones. Such measures increase the thermal insulation of the envelope and reduce the energy need for space heating, but also reduce the daylight availability, due to the lower visible transmittance of highly insulated windows. This drawback may have strong effect in Norway, where the daylight availability in the winter season is little. This paper investigates into the consequences on energy use for space heating and electricity use for lighting given by the substitution of existing windows with highly insulated windows in Norwegian residential buildings. Three apartment buildings with different construction systems of the external facades and located in Trondheim are investigated. The buildings were built before the 1900, in the first decade of the 1900, and in the 1960s, respectively. The U-value of the external facades varies from 0.96 W/m2K to 0.26 W/m2K, and the U-value of the existing windows varies from 1.6 W/m2K to 2.8 W/m2K. The new windows have a U-value of 0.5 W/m2K. Scenarios are modelled to simulate the use patterns of artificial lighting in the apartments. Use patterns are modelled by considering occupancy hours and type of activity to cover different scenarios. Results show that the substitution of the existing windows reduces the median value of the Daylight Autonomy by at least 50%, and the additional electricity use for lighting is calculated to be between 17% and 64% of the potential energy saving for space heating.

The 'Beat The Heat!' project was a project of the Australian Federal Governments 'Low Income Energy Efficiency Program' (LIEEP). This project aimed to enhance the resilience and improve the comfort and wellbeing of Adelaide households during South Australias long, hot summers. The installation of ceiling insulation and new air-conditioners in the main living areas of low-income households were two of the key interventions made through this project. Total electrical energy consumption of each household and the air-conditioner were monitored following these interventions and compared with electricity bills before the installation, during matched summer periods. Indoor temperatures of the main living area were also monitored, following the intervention, to assess the improvement in thermal comfort. Significant differences between the energy use before and after household interventions, along with associated household perceptions, are discussed in this paper. Specifically, the impact on energy consumption of factors such as household income, the source of cooling energy prior to the intervention and differences in climate and thermal comfort are explored. For houses where an old, inefficient and ineffective air-conditioner was replaced by a new, efficient split system (3.23 < EER < 4.83), a 16% average reduction in mains energy was observed following the intervention. This was partly driven by an overall reduction in electrical energy for cooling, but was also influenced by a change in the households ability to enjoy a more comfortable environment Refereed/Peer-reviewed

The European Directives promote the energy consumption assessment in residential and industrial sectors in order to identify specific measures for getting energy savings. This paper presents the results of the energy use analysis, carried out for a wine manufacturing firm located in Southern Italy. The energy consumptions of the main wine production processes are investigated, showing that the cooling is the most energy-intensive user. Potential actions as thermal insulation of storage tanks and integration of solar cooling system are proposed and analyzed in terms of energy saving to improve energy efficiency of the refrigeration process in the winery.

This paper focuses on the design and the optimization of Organic Rankine Cycle (ORC) for LNG regasification plants. This technology is a promising solution with large benefits attainable in terms of primary energy savings compared to both Open Rack Vaporizer (ORV) and Submerged Combustion Vaporizer (SCV) technologies. Different cycle configurations are investigated including the option of multilevel condensation plants. The adoption of several working fluid candidates is analyzed and different design constraints are included to obtain a more reliable solution. The optimal combinations of cycle configuration and working fluid are presented with a preliminary design of the main components. Finally a dependency study on the seawater temperature is carried out.

This paper aims at presenting the development of a calibrated building energy simulation model of a school building to study the impact of improving the ventilation system on energy performance. The simulation model was developed with the DesignBuilder/Energyplus software and it was calibrated based on data collected during an energy audit to the school building. Schools need high outdoor airflow rates to remove indoor air contaminants related to occupants and building components, thus requiring mechanical ventilation systems. Due to budget restrictions, school managers decided to schedule the building management system to keep the HVAC systems active only between 6:00 am and 10:00 am. According to the values measured in this school, it was patent that the CO2 concentration was too high in certain periods. Too high peak values undermine the indoor air quality in the remaining occupancy time of the classroom, harming the work conditions for teachers and students. To solve this problem, an extended usage schedule of the mechanical ventilation was simulated (8:00 am to 5:00 pm) according to the required enhancement of indoor air quality, which together with the adoption of the new calculated fresh air flow rates will enhance air quality while avoiding excessive cost, thus increasing energy efficiency.

The Public Procurement has always been a demand-side policy measure with great opportunities in terms of spurring innovation at the scale of products and/or services. A support for a sustainable development in the field of energy and buildings may came from different types of Public Procurement: Green Public Procurement (GPP), Sustainable Public Procurement (SPP) and Public Procurement of Innovation (PPI). Within this framework, the paper presents a case study where PPI has been used to promote the development of innovative solutions for upgrading school buildings in terms of increased energy efficiency and sustainability.

Energy retrofitting of historic or existing buildings is a challenge that it has not yet been properly fully addressed. Multiple projects and methodologies are published every day but neither of them with the holistic approach that will assure complete success since the design phase. This stock is never considered as a whole. Its components are installed, serviced and maintained by different companies and in different stages without a holistic approach to the overall building operation. The result is a lack of energy efficiency and feedback of the solutions implemented once the buildings are refurbished. Nevertheless, existing buildings play a key role in the achievement of the ambitious energy saving and greenhouse gas reduction targets that Europe has fixed for 2020 and 2050. Research has demonstrated that the impact in terms of decrease of energy use and CO2 will be strong, considering that, in Europe, 80% of the 2030 building stock already exists and 30% are historical buildings. To achieve these goals, reliable data about energy consumption, building components and systems performance of the existing building stock is needed. This paper presents a pre-assessment methodology to tackle the energy retrofitting of historic and existing residential buildings based on the Maturity Matrix Assessment. The maturity of the implementation of energy efficiency measures in Brussels historic residential stockis evaluated to determine future appropriate implementations. The matrix synthetizes appropriate strategies for this specific stock and provides a global map of the problematic, requirements and solutions., SCOPUS: cp.p, info:eu-repo/semantics/published

Architectural constraints are a crucial aspect in energy retrofitting of historic buildings. Usual global interventions are often not allowed since preserving historical values of the building stock is mandatory. In this paper, the authors provide an alternative procedure by identifying the most profitable local interventions in order to maintain the architectural values during the restoration and energy retrofitting operations. So, thermal zones prioritization is the key element considered in this study. Its aim is to analyse which energy efficiency measures could be applied to a listed building, but at certain technological elements rather than a unique choice for the entire building envelope. Thus it will prove that you can work with individual elements of the building without compromising the protection of architectural good. The attention was placed in promoting single measures and improving the quality of the built environment. The case study is an historical building in Rome, currently used for university purposes. The analysis was carried out through a building simulation model so that to assess the building energy performance before and after the selected interventions. The chosen software is TRNSYS. This approach shows how interventions, usually not applicable at the building scale, would be beneficial if applied at local scale such as a single thermal zone or a single technological unit. The authors built a reference scenario and, for each identified thermal zone, tested the energy efficiency improvement in terms of heating demand reduction coming from the hypothesized local intervention.

Within EU, the food industry is currently ranked among the energy-intensive sectors, mainly as a consequence of the cooling system shareover the total energy demand. As such, the definition of appropriate key performance indicators (KPI) for ammonia chillers can play a strategic role for the efficient monitoring of the energy performance of the cooling systems. The goal of this paper is to develop an appropriate management approach, to account for energy inefficiency of the single compressors, and to identify the specific variables driving the performance outliers. To this end, a new KPI is proposed which correlates the energy consumption and the different process variables. The construction of the new indicator was carried out by means of multivariate statistical analysis, in particular using Kernel Partial Least Square (KPLS). This method is able to evaluate the maximum correlation between dataset and energy consumption employing nonlinear regression techniques. The validity of the new KPI is discussed on a case study relevant to the cooling system of a frozen ready meals industry. The assessment of the proposed metric is one against Specific Energy Consumption (SEC) like indicator, typically used in the context of the Energy Management Systems.

Currently, Power-to-Gas technologies are considered viable solutions to face the onset problems associated with renewable capacity firming. Indeed, carbon-free hydrogen production converting renewable electricity excess and its injection into natural gas pipelines is considered a short- to medium-term solution. In this way, the so-called H 2 NG blends can be fired within internal combustion engines and micro gas turbines operating in CHP mode, offering better environmental-energy performances in machines. As regards the distributed energy generation scenario, the local H 2 production by means of electrolysis for methane enrichment will be more cost-effective if the oxygen is fruitfully used instead of venting it out like a by-product, as usually occurs. This study focuses on the usefulness of using that oxygen to enrich the air-fuel mixture of an internal combustion engine for micro-CHP applications, once it has been fuelled with H 2 NG blends. Thus, the main aim of this paper is to provide a set of values for benchmarking, in which H 2 NG blends, ranging in 0%-15% vol., burn within an ICE in partial oxy-fuel conditions. In particular, a preliminary energy analysis was carried out based on experimental data, reporting the engine operating parameters, gains and losses in both electrical and heat recovery efficiency. The oxygen content in the air varies up to 22% vol. A Volkswagen Blue Tender CHP commercial version (19.8 kW el. of rated electrical power output) was considered as the reference machine and its energy characterization was reported when it operated under those unconventional conditions.

This paper investigates the CO2 cost pass-through to electricity prices of the Baltic market, as well as CO2 prices effect on merit order of generation sources and consequently marginal changes of CO2 emissions in response to changes in electricity demand. Authors use multiple regression analysis to demonstrate that a 1 EUR change in the price of CO2 emissions would increase the price of the Nordic power market by 0.55 EUR and in the Baltic countries by 0.67 EUR. Additionally, it has been shown that CO2 prices significantly impact merit order of electricity generators and consequently marginal emissions of CO2 due to reduction of electricity consumption in case of energy efficiency measures. Based on analysis, it can be concluded that, in the low price scenario (7.5 EUR per ton of CO2), combined heat and power plants are marginal generators emitting 0.25 tons of CO2 per 1MWh in cogeneration mode. If CO2 prices are above 20 EUR, the marginal emitter will become oil shale power plants that emit around 1 ton of CO2 per 1 MWh of electricity.

This paper shows a micro-economic based quantitative analysis scheme to evaluate the energy efficiency of cities based on quality of life and energy consumption. By representing the quality of life by utility, this study developed a CES-based model to estimate the individual demand of non-mobility goods, car trips, and public transport trips at the maximum utility level. Energy consumption is estimated by the demand of goods. An energy efficiency index is developed to show the relative energy consumption on the certain quality of life. We applied this model to Nagasaki region. Higher energy efficiency zones were found in city center and along the mass transit lines. Such findings suggest that a compact urban structure and higher public transport accessibility could increase energy efficiency.

Transition towards energy efficient cities requires an effective upgrade of all the different areas of urban energy production, distribution and use. The paper presents a method for collecting the information required for analysing the technical variation of strengths and weaknesses in infrastructure capabilities in European medium-sized cities, as well as to help identify best practices and tools for enhancing the energy performance of city energy systems.

The research of five educational institution buildings and three municipality department buildings were carried out in Liepāja municipality, Latvia. Aim of the study is to draw attention to finding balance among energy efficiency, thermal comfort and indoor air quality dilemma. The research of recently renovated public sector buildings was done. The combination of factors that form microclimate and indoor air quality are described in the paper. Emphasis is put on a person's ability to perform mental tasks in regards of changes in thermal comfort and air quality. Surveys of buildings’ inhabitants and economic aspects of human productivity changes were carried out in the research. Also four ventilation scenarios have been modelled and economic benefits of each scenario have been assessed. Different air exchange rates can make 19% human productivity improvement. Using ventilation systems as it is designed already gives economic benefit and not all the buildings need additional investments for new system implementation. The economic benefit in four buildings is more than 20 000 euro already in second year. The priority for planning, designing and managing education institution buildings should be indoor environment and thermal comfort of inhabitant.

s The paper presents a review of indirect evaporative cooling (IEC) operating conditions and performances. This cooling technology is promising to develop in the near future due to its very low energy consumption and high efficiency in its range of applications. The review is presenting in details: operating conditions and performances. Having very low energy consumption comparing to classic cooling, the IEC technology is environmental friendly and has very low global warming impact. The single disadvantage of IEC is the water consumption. The review also includes a study concerning the limits of IEC for different locations world-wide.

The paper presents actual knowledge concerning the indirect evaporative cooling (IEC). This cooling technology is promising to develop in the near future due to its very low energy consumption and high efficiency in its range of applications. The review is presenting in details: theory, working principles, flow and construction. The IEC equipment and technology is suitable in different air conditioning applications: commercial, industrial, residential or data centres. The IEC technology is completely environmental friendly and has very low global warming impact. The single disadvantage of IEC is the water consumption.

This paper has as its main focus to define the drivers of retrofitting shopping centres. The drivers will provide the basis for developing energy retrofitting concepts, offering amongst other things, constructive technology, an understanding of typical functional patterns and socio-cultural aspects and an understanding of potentials associated with interaction with local energy grids. The primary focus of the study is energy use, but the fields of facilities, functions, management, ergonomics, safety and logistics are also studied, because sustainable shopping centres in addition to being energy efficient are commercially viable, accessible social arenas for all sections of society.