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17 pages, 4249 KiB

Open AccessArticle

Simulation and Experimental Study on the Use of Ventilation Air for Space Heating of a Room in a Low-Energy Building

by Piotr Michalak

Energies 2023, 16(8), 3456; https://doi.org/10.3390/en16083456 - 14 Apr 2023

Cited by 2 | Viewed by 1702

Abstract

In thermally modernised buildings, sharing of ventilation heat loss becomes more significant. In the case of the application of ventilation with heat recovery, especially during transitional periods, there arises a question of whether an air system makes it possible to maintain the required [...] Read more.

In thermally modernised buildings, sharing of ventilation heat loss becomes more significant. In the case of the application of ventilation with heat recovery, especially during transitional periods, there arises a question of whether an air system makes it possible to maintain the required indoor air temperature without the necessity of using a basic hydronic heating system. This paper presents the application of a simple thermal network model of a building zone to simulate indoor air temperature in a single room of a multi-storey building with a mechanical ventilation system with heat recovery. Ventilation air was supposed to be the only heat source and its ability to maintain the required indoor air temperature was checked in simulations and then compared with measurements. The 5R1C thermal network model of a building zone was used for simulations. Comparison with measurements showed the Mean Absolute Error (MAE) and Root Mean Square Error (RMSE) of indoor air calculation to be 2.37 °C and 2.45 °C, respectively. When including heat flux from the bottom storey through the floor, MAE = 1.28 °C and RMSE = 1.38 °C were obtained. Full article

(This article belongs to the Special Issue Energy Performance, Management and Recovery in Buildings)

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16 pages, 12769 KiB

Open AccessArticle

Mapping Seasonal Variability of Buildings Electricity Demand profiles in Mediterranean Small Islands

by Simone Ferrari, Federica Zagarella, Paola Caputo and Marco Beccali

Energies 2023, 16(4), 1568; https://doi.org/10.3390/en16041568 - 4 Feb 2023

Cited by 2 | Viewed by 1921

Abstract

In communities with a high tourist influx and warm climate, such as Mediterranean small islands, the energy demands for space cooling and domestic hot water are expected to significantly increase during summer. Considering the current energy context, for succeeding energy transition and reducing [...] Read more.

In communities with a high tourist influx and warm climate, such as Mediterranean small islands, the energy demands for space cooling and domestic hot water are expected to significantly increase during summer. Considering the current energy context, for succeeding energy transition and reducing the dependency on not endogenous fossil fuels, it is paramount to increase the deployment of renewable sources of energy, especially wind and solar which, however, are aleatory and unpredictable. Hence, to reduce the high costs for energy supply in these contexts, the analysis of the variation of energy consumption is fundamental. Moreover, mapping the spatial distribution of energy profiles can be useful to have an overview at a large scale of the considered building stock. Within this frame, a Geographic-Information-System-based procedure was implemented to estimate the residential buildings energy demand profiles, focusing on the seasonal variation. The adopted method can provide a valid supporting tool for decision makers that have to implement smart energy strategies in contexts with a high variation of the energy demand and evident electricity summer peaks. The method for mapping the energy demand profiles, implemented on the small island of Pantelleria, can be applied to other similar contexts, also supporting energy policies in the implementation of renewable energy communities. Full article

(This article belongs to the Special Issue Energy Performance, Management and Recovery in Buildings)

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19 pages, 7292 KiB

Open AccessArticle

Investigation of the Visual Environment of Railway Station Stairs Using Qualitative and Quantitative Evaluation Methods

by Jaeyoung Heo, Miki Kozaki, Takaaki Koga, Kotaroh Hirate and Hyun Bae Kim

Energies 2022, 15(19), 7013; https://doi.org/10.3390/en15197013 - 24 Sep 2022

Cited by 1 | Viewed by 1504

Abstract

A qualitative evaluation was performed by comprehensively considering the lighting environment of each staircase of 20 railway stations in Tokyo, the width of the stairs, the type of ceiling, wall lighting fixtures, and the color. As a result of the quantitative evaluation of [...] Read more.

A qualitative evaluation was performed by comprehensively considering the lighting environment of each staircase of 20 railway stations in Tokyo, the width of the stairs, the type of ceiling, wall lighting fixtures, and the color. As a result of the quantitative evaluation of 20 stairs, it was found that a difference of up to 400 lx occurred in the measurement results of the entrance, exit, and middle landing, even for the same stairs. As a result of qualitative evaluation, it was found that the quantitative evaluation result and the simple proportional relationship were not established. It was found that simply physically brightening a space cannot make a comfortable and safe space, and in some cases, glare is likely to occur. As a result of the analysis of variance and correlation analysis, it was found that the characteristics of the space, especially the material of the wall and the location of the lighting equipment, had a large effect on the impression of the space. As a result of simulation analysis, it was found that the performance varied greatly depending on the installation location of the lighting. In particular, the method of installing the line light source close to the ground was effective. In designing stair lighting for public facilities in the future, it is considered that qualitative factors such as the finishing of walls and ceilings, installation positions, and angles of lighting fixtures, which are environmental components other than lighting, should also be considered. Full article

(This article belongs to the Special Issue Energy Performance, Management and Recovery in Buildings)

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16 pages, 3245 KiB

Open AccessArticle

Seasonal Performance Evaluation of Air-Based Solar Photovoltaic/Thermal Hybrid System

by Youngjin Choi

Energies 2022, 15(13), 4695; https://doi.org/10.3390/en15134695 - 27 Jun 2022

Cited by 2 | Viewed by 1600

Abstract

Recently, the use of novel renewable energy has attracted attention for suppressing the generation of carbon dioxide to prevent global warming. There is growing interest in energy reduction in buildings using solar energy because of its ease of use and repair and excellent [...] Read more.

Recently, the use of novel renewable energy has attracted attention for suppressing the generation of carbon dioxide to prevent global warming. There is growing interest in energy reduction in buildings using solar energy because of its ease of use and repair and excellent maintenance. Therefore, in this study, air-based Photovoltaic thermal (PVT) systems, which can increase the utilization of solar energy, are compared with the existing PV system through measurement. PVT systems can increase the amount of power generation by lowering the temperature of the panel using air passing through the lower part of the panel. It is also possible to use the heated air obtained from the panel as indoor heating or for supplying hot water in a building. As a result of measuring the performance of existing PV panels and PVT panels under the same weather conditions, the power generation efficiency of PVT panels through which air passes increases compared to PV panels. Overall, an air-based PVT system can utilize solar energy about three times more than existing PV systems by utilizing solar heat and solar power. In summer, thermal collection and power generation by PVT were 51.9% and 19.0%, respectively, and power generation by PV was 18.0%. In contrast, the amount of thermal collection and power generation in winter was 43.5% and 20.3%, respectively, and the amount of power generated by PV was 18.7%. As such, it is necessary to review methods for utilizing the increase in power generation in winter and thermal collection in summer. Full article

(This article belongs to the Special Issue Energy Performance, Management and Recovery in Buildings)

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19 pages, 3101 KiB

Open AccessArticle

Low and Ultra-Low Temperature District Heating Equipped by Heat Pumps—An Analysis of the Best Operative Conditions for a Swiss Case Study

by Riccardo Toffanin, Paola Caputo, Marco Belliardi and Vinicio Curti

Energies 2022, 15(9), 3344; https://doi.org/10.3390/en15093344 - 4 May 2022

Cited by 7 | Viewed by 2061

Abstract

The manuscript analyses the management of low and ultra-low-temperature district heating systems (DHS) coupled with centralised and decentralised heat pumps. Operative conditions are defined in order to satisfy the heating needs without overloading the electric grid. The results are achieved by dynamic simulations, [...] Read more.

The manuscript analyses the management of low and ultra-low-temperature district heating systems (DHS) coupled with centralised and decentralised heat pumps. Operative conditions are defined in order to satisfy the heating needs without overloading the electric grid. The results are achieved by dynamic simulations, based on a real DHS located in southern Switzerland. At the building level, the heating needs are estimated considering real data and simultaneous energy simulations. Two DHS configurations, alternatives to the existing one, are simulated and suitable parameters for the management of the DHS are selected. The global performance of the two DHS is evaluated by KPIs also including the flexibility and the impact on the electric peak due to heat pumps. The achieved results are discussed providing suggestions for the stakeholders involved in DHS management for an optimal matching of the electric grid and thermal networks towards a reduction of the peak power. The rule-based control strategies defined allow the expected electric peak shaving and load levelling, conversely, the yearly energy consumptions are lightly increased and have to be further investigated. The outcomes demonstrate a global better performance of the ultra-low temperature DHS in terms of response to the applied control strategies and of energy savings. Full article

(This article belongs to the Special Issue Energy Performance, Management and Recovery in Buildings)

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11 pages, 3398 KiB

Open AccessArticle

Analysis of Solar Energy Utilization Effect of Air-Based Photovoltaic/Thermal System

by Youngjin Choi and Hyun Bae Kim

Energies 2021, 14(24), 8586; https://doi.org/10.3390/en14248586 - 20 Dec 2021

Cited by 6 | Viewed by 2341

Abstract

Recently, the use of new and renewable energy sources to reduce carbon dioxide emissions and minimize global warming has attracted attention. Among the different renewable energy sources, solar energy is utilized for energy reduction in buildings because of its ease of use and [...] Read more.

Recently, the use of new and renewable energy sources to reduce carbon dioxide emissions and minimize global warming has attracted attention. Among the different renewable energy sources, solar energy is utilized for energy reduction in buildings because of its ease of use and excellent maintenance and repair. In this study, an air-based photovoltaic/thermal (PVT) system that improves solar energy utilization was developed, and its performance was experimentally compared with that of the existing photovoltaic (PV) system. The PVT system could increase the amount of generated power by decreasing the panel temperature raised by the air passing through the lower part of the panel. Moreover, it was possible to use the high-temperature air collected from the panel for heating or hot-water supply in the building. Based on the experimental results obtained for the PV and PVT panels subjected to the same weather conditions, the power generation efficiency of the PVT panel through which air was passed increased by approximately 10.1% compared to that of the PV panel. In addition, a heat collection efficiency of approximately 46.6% was generated by the temperature increase of the air passing through the PVT panel. Full article

(This article belongs to the Special Issue Energy Performance, Management and Recovery in Buildings)

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21 pages, 2889 KiB

Open AccessArticle

Air to Water Generator Integrated Systems: The Proposal of a Global Evaluation Index—GEI Formulation and Application Examples

by Lucia Cattani, Paolo Cattani and Anna Magrini

Energies 2021, 14(24), 8528; https://doi.org/10.3390/en14248528 - 17 Dec 2021

Cited by 7 | Viewed by 3531

Abstract

Due to water scarcity, in the last few decades, air-to-water generator (AWG) technology, whose useful effect is the extraction of water from air, has been improved. In particular, in the last few years, advanced AWG integrated systems have been developed. Such systems permit, [...] Read more.

Due to water scarcity, in the last few decades, air-to-water generator (AWG) technology, whose useful effect is the extraction of water from air, has been improved. In particular, in the last few years, advanced AWG integrated systems have been developed. Such systems permit, not only to condense water from air, but also the smart use of the by-side effects of the process in order to partially or totally cover the heating ventilation air conditioning (HVAC) needs of a building. Presently, there are no evaluation tools that permit a complete comparison among AWG machines, taking into account all the useful effects that can be obtained at the same time and with the same energy input. The current work, starting from the need for such a tool, proposes a global index whose formulation considers all useful effects of an integrated system, the energy required to obtain them, and the integration degree of the machine. The index translates into a single number the system global efficiency, by means of a particular combination of existing efficiency indicators. In its extended formulation, it can be applied, not only to AWGs, but also to other HVAC integrated systems, as well as to combinations of non-integrated and integrated solutions. In addition to equations, the paper provides calculation examples and a case study in order to show the practical application and advantages of GEI. Full article

(This article belongs to the Special Issue Energy Performance, Management and Recovery in Buildings)

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20 pages, 7257 KiB

Open AccessArticle

Novel Dual Walling Cob Building: Dynamic Thermal Performance

by Kaoutar Zeghari, Ayoub Gounni, Hasna Louahlia, Michael Marion, Mohamed Boutouil, Steve Goodhew and François Streif

Energies 2021, 14(22), 7663; https://doi.org/10.3390/en14227663 - 16 Nov 2021

Cited by 10 | Viewed by 3144

Abstract

This paper emphasizes the experimental and numerical study of new cob mixes used for insulation and load bearing wall elements. The experimental study provides complete datasets of thermal properties of the new walling materials, using cob with density ranging from 1107 kg/m³ [...] Read more.

This paper emphasizes the experimental and numerical study of new cob mixes used for insulation and load bearing wall elements. The experimental study provides complete datasets of thermal properties of the new walling materials, using cob with density ranging from 1107 kg/m³ to 1583 kg/m³ for structural walls and less than 700 kg m⁻³ for insulation walls. Various mixes of French soils and fibres (reed, wheat straw, hemp shiv, hemp straw, and flax straw) with different water contents are studied. The lowest average thermal conductivity is obtained for the structural cob mix prepared of 5% wheat straw and 31% of water content. The insulation mix, prepared with 25% reed and 31% water content, has the lowest thermal conductivity. Investigation of diffusivity, density, and heat capacity shows that, when thermal conductivity is lower than 0.4 W m⁻¹ K⁻¹, the decrease in cob density leads to better insulation values and higher heat capacity. Little variation is noticed regarding the density and heat capacity for cob mixes with thermal conductivity higher than 0.4 W m⁻¹ K⁻¹. Furthermore, the non-uniformity of local thermal conductivity and heat losses through the samples is due mainly to the non-uniform distribution of fibres inside the mixes inducing an increase in heat loss up to 50% for structural walls and 25% for insulation walls. Cob thermal properties are used in a comparative simulation case study of a typical house under French and UK climatic conditions. The energy performance of the conventional building is compared to a dual walled cob building, showing remarkable reduction in energy consumption as the cob walls, whilst maintaining comfortable indoor conditions without additional heating. Full article

(This article belongs to the Special Issue Energy Performance, Management and Recovery in Buildings)

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24 pages, 6257 KiB

Open AccessFeature PaperArticle

Detailed Thermodynamic Modeling of Multi-Zone Buildings with Resistive-Capacitive Method

by Filip Belić, Dražen Slišković and Željko Hocenski

Energies 2021, 14(21), 7051; https://doi.org/10.3390/en14217051 - 28 Oct 2021

Cited by 11 | Viewed by 2406

Abstract

Increased use of energy in buildings and HVAC systems requires advanced control schemes like model-based control to improve energy efficiency, which in turn requires accurate thermodynamic models of buildings. The Resistive-Capacitive (RC) method is a popular and versatile approach for thermal modeling of [...] Read more.

Increased use of energy in buildings and HVAC systems requires advanced control schemes like model-based control to improve energy efficiency, which in turn requires accurate thermodynamic models of buildings. The Resistive-Capacitive (RC) method is a popular and versatile approach for thermal modeling of buildings. Despite this, it is not easy to find practical solutions of implementation of the RC method. It is the goal of this paper to clarify the RC method and demonstrate simple implementation of this method, especially for multi-zone buildings, which have more potential for energy savings from use of model-based control. This paper provides two contributions. First is a detailed explanation of the RC method, focusing on its use for developing a structure of a model and first-principles approach for estimation of parameters of a model. Second is a demonstration of an algorithm that enables automatic development of the structure of a model from basic information about a building (layout, construction elements) and its combination with data-based parameter estimation. Use of the algorithm is presented with a case-study on industrial multi-zone building, for which such a grey-box model is developed and analyzed. The resulting model is rapidly developed and used in a simulation with the measured data. The outputs of the model are compared with the measured temperatures and they show good fit. Full article

(This article belongs to the Special Issue Energy Performance, Management and Recovery in Buildings)

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23 pages, 6088 KiB

Open AccessArticle

Downcycling and Upcycling in Rehabilitation and Adaptive Reuse of Pre-Existing Buildings: Re-Designing Technological Performances in an Environmental Perspective

by Antonello Monsù Scolaro and Stefania De Medici

Energies 2021, 14(21), 6863; https://doi.org/10.3390/en14216863 - 20 Oct 2021

Cited by 15 | Viewed by 4558

Abstract

The abandonment of the built heritage, as a result of functional or technological obsolescence or as a consequence of cultural, social, and economic trends, is steadily increasing. This great number of buildings, worldwide spread, offers a huge opportunity to reduce the environmental impacts [...] Read more.

The abandonment of the built heritage, as a result of functional or technological obsolescence or as a consequence of cultural, social, and economic trends, is steadily increasing. This great number of buildings, worldwide spread, offers a huge opportunity to reduce the environmental impacts related to the construction industry. Nonetheless, the recovery and reuse interventions that require the implementation of residual technological performance, to accommodate new uses, are not always environmentally neutral. Therefore, a new design approach needs to be developed so as to improve the buildings’ technological performance and enhance resources and energy already incorporated in buildings. The circular economy principles in the building sector, performance-based building design together with downcycling and upcycling theories are applied to develop a methodology aiming to reduce the environmental impacts within the rehabilitation and refurbishment design process. Starting from the building analysis phase (historical, material, construction) residual performance is evaluated; then the design phase demonstrates that, according to downcycling and upcycling design strategies applied on building components and materials, it is possible improving the building to the required new uses while minimizing transformations and effectively reducing related environmental impacts. The reduction of environmental impacts depends on a careful assessment of the residual technological and structural performance that the building still provides, by involving limited performance implementations to balance rehabilitation needs and environmental protection goals. Full article

(This article belongs to the Special Issue Energy Performance, Management and Recovery in Buildings)

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20 pages, 20559 KiB

Open AccessArticle

An Explicit Finite Element Method for Thermal Simulations of Buildings with Phase Change Materials

by Hongxia Zhou, Åke Fransson and Thomas Olofsson

Energies 2021, 14(19), 6194; https://doi.org/10.3390/en14196194 - 28 Sep 2021

Cited by 11 | Viewed by 2711

Abstract

The thermal performance of building envelopes is essential for building thermal comfort and the reduction of building energy requirements. Phase change materials (PCMs) implemented in building envelopes can improve thermal performance. An explicit finite element method (ex-FEM) has been developed based on a [...] Read more.

The thermal performance of building envelopes is essential for building thermal comfort and the reduction of building energy requirements. Phase change materials (PCMs) implemented in building envelopes can improve thermal performance. An explicit finite element method (ex-FEM) has been developed based on a previous study to investigate the heat transfer performance through building walls with installed PCMs. For verification, we introduce an electrical circuit analogy (ECA) method. For model validation, at first, COMSOL is used. For comparison, data were collected from experiments using a small hotbox, part of the sides are covered by PCMs with different configurations. This work shows how the ex-FEM model can predict the wall’s temperature profile with and without incorporated PCM. With the implementation of PCMs, the work problematizes unpredictable influences for modeling. In addition, the study introduces results from simulations of sequencing of PCM layers in wall construction. Full article

(This article belongs to the Special Issue Energy Performance, Management and Recovery in Buildings)

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20 pages, 3604 KiB

Open AccessFeature PaperArticle

HVAC Energy Saving Strategies for Public Buildings Based on Heat Pumps and Demand Controlled Ventilation

by Alessandro Franco, Lorenzo Miserocchi and Daniele Testi

Energies 2021, 14(17), 5541; https://doi.org/10.3390/en14175541 - 5 Sep 2021

Cited by 22 | Viewed by 4343

Abstract

The paper analyzes and compares the perspectives for reducing the energy consumption associated to the operation of Heating Ventilation and Air Conditioning system for climatic control of large-size non-residential buildings. Three different control strategies are considered comparing the use of boiler and heat [...] Read more.

The paper analyzes and compares the perspectives for reducing the energy consumption associated to the operation of Heating Ventilation and Air Conditioning system for climatic control of large-size non-residential buildings. Three different control strategies are considered comparing the use of boiler and heat pumps as heating systems and analyzing the use of demand-controlled ventilation, operating on the effective occupancy of the building. The control strategies are applied to two different educational buildings with shapes representative of typical educational structures. The results of the analysis show how the energy consumption can be reduced up to 70%, shifting from the actual values of the energy intensity of over 300 kWh/m² for year to values of less than 100 kWh/m² per year. The significance of the energy savings achieved in such different buildings has led to the identification of a possible benchmark for HVAC systems in the next future years which could help reach the environmental targets in this sector. Full article

(This article belongs to the Special Issue Energy Performance, Management and Recovery in Buildings)

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16 pages, 10773 KiB

Open AccessEditor’s ChoiceArticle

A GIS-Based Procedure for Estimating the Energy Demand Profiles of Buildings towards Urban Energy Policies

by Simone Ferrari, Federica Zagarella, Paola Caputo and Giuliano Dall’O’

Energies 2021, 14(17), 5445; https://doi.org/10.3390/en14175445 - 1 Sep 2021

Cited by 16 | Viewed by 3225

Abstract

Assessing the existing building stock’s hourly energy demand and predicting its variation due to energy efficiency measures are fundamental for planning strategies towards renewable-based Smart Energy Systems. However, the need for accurate methods for this purpose in the literature arises. The present article [...] Read more.

Assessing the existing building stock’s hourly energy demand and predicting its variation due to energy efficiency measures are fundamental for planning strategies towards renewable-based Smart Energy Systems. However, the need for accurate methods for this purpose in the literature arises. The present article describes a GIS-based procedure developed for estimating the energy demand profiles of urban buildings based on the definition of the volumetric consistency of a building stock, characterized by different ages of construction and the most widespread uses, as well as dynamic simulations of a set of Building Energy Models adopting different energy-related features. The simulation models are based on a simple Building Energy Concept where selected thermal zones, representative of different boundary conditions options, are accounted. By associating the simulated hourly energy density profiles to the geo-referenced building stock and to the surveyed thermal system types, the whole hourly energy profile is estimated for the considered area. The method was tested on the building stock of Milan (Italy) and validated with the data available from the annual energy balance of the city. This procedure could support energy planners in defining urban energy demand profiles for energy policy scenarios. Full article

(This article belongs to the Special Issue Energy Performance, Management and Recovery in Buildings)

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Review

Jump to: Research

26 pages, 6543 KiB

Open AccessReview

Global Research Trends on Building Indoor Environmental Quality Modelling and Indexing Systems—A Scientometric Review

by Soheil Roumi, Fan Zhang and Rodney A. Stewart

Energies 2022, 15(12), 4494; https://doi.org/10.3390/en15124494 - 20 Jun 2022

Cited by 7 | Viewed by 2648

Abstract

The purpose of this study is to provide a holistic review of two decades of research advancement in the indoor environmental quality modelling and indexing field (IEQMI) using bibliometric analysis methods. The explicit objectives of the present study are: (1) identifying researchers, institutions, [...] Read more.

The purpose of this study is to provide a holistic review of two decades of research advancement in the indoor environmental quality modelling and indexing field (IEQMI) using bibliometric analysis methods. The explicit objectives of the present study are: (1) identifying researchers, institutions, countries (territories), and journals with the most influence in the IEQMI topic; (2) investigating the hot topics in the IEQMI field; and (3) thematically analysing the keyword evolution in the IEQMI field. A scientometric review was conducted using the bibliometric data of 456 IEQMI research articles published in the past two decades. VOSviewer software was employed for bibliometric analysis, and the SciMAT tool was used to investigate the keywords’ thematic evolution in three sub-periods (2004–2009; 2010–2015; 2016–2021). Results show that there is a continuous increment in the number of published papers in the field of IEQMI, and 60 out of 193 countries in the world have been involved in IEQMI studies. The IEQMI research mainly focuses on: (a) thermal comfort and energy efficiency; (b) occupant satisfaction and comfort; (c) IAQ and health issues; (d) methods and procedures. This field has undergone significant evolution. While ‘indoor environmental quality was initially the only theme in the first period’, ‘occupant satisfaction’, ‘buildings’, ‘impact’, ‘building information modelling’, and ‘health’ were added as the main thematic areas in the second period; ‘occupant behaviour’ and ‘energy’ were novel themes in IEQMI studies receiving much attention in the third period. Full article

(This article belongs to the Special Issue Energy Performance, Management and Recovery in Buildings)

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