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A special issue of Energies (ISSN 1996-1073). This special issue belongs to the section "G: Energy and Buildings".

Deadline for manuscript submissions: closed (30 November 2020) | Viewed by 34722

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Special Issue Editor

Dr. Vítor Leal

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Guest Editor

Department of Mechanical Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
Interests: energy systems; energy in buildings; energy planning; sustainability

Special Issue Information

Dear colleagues:

Buildings represent about 36% of global final energy consumption and nearly 40% of total direct and indirect GHG emissions. Nonetheless, the energy demand of buildings can be dramatically reduced, both in new and in existing buildings, through a combination of design techniques, efficient technologies, and integration of local renewable energies.

At the conceptual level, a renewed discussion on energy efficiency of the buildings is timely because of several factors: (i) it still suffers from the non-economically-rational behavior of agents; (ii) there is a growing perception that energy efficiency effects are often offset by direct and indirect rebound effects; (iii) the emergence of cheap on-site renewable energy technologies like photovoltaics is changing the optimal demand–supply balance point; (iv) and the change ahead in terms of the structure of electrical systems requires much more flexibility of the loads, among which demand-side management in buildings can play a very important role.

As the world faces the need for a quick change in the energy system(s), the research priorities that can best contribute to these efforts must now more than ever include concerns like cost, socioeconomic acceptance, and behavioral issues, in order to facilitate a quick and massive adoption. This Special Issue thus intends to promote a comprehensive approach to the theme of Energy Efficiency and Innovative Energy Systems in Buildings, including topics such as:

Energy efficiency and performance metrics;
Performance assessment of the existing stock;
Integration and synergies with on-site renewables;
Innovative design strategies;
Innovative technological solutions;
Maximization of electric demand–response potential;
Financing instruments for energy efficiency actions;
Rebound effects and behavioural issues;
Non-energy benefits of actions;
Retrofit strategies and case studies.

Prof. Dr. Vítor Leal
Guest Editor

Manuscript Submission Information

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Keywords

Energy efficiency
Metrics and performance
Demand side management
Building integrated renewables
Innovative solutions
Retrofit strategies
Rebound effect
Behavioral issues
Financing instruments

Published Papers (13 papers)

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Research

Jump to: Review

18 pages, 2426 KiB

Open AccessArticle

Indoor Comfort, Thermal Indices, and Energy Assessment of Multi-Family Colonial Revival Style Buildings

by Timothy O. Adekunle

Energies 2021, 14(22), 7468; https://doi.org/10.3390/en14227468 - 09 Nov 2021

Cited by 1 | Viewed by 1302

Abstract

Colonial Revival style residences have unique architectural features amongst others. They are common multi-family residences in the United States with no or limited information about their performance. The research purpose is to assess indoor comfort, energy performance, and thermal indices in multi-family Colonial Revival style residences. The research questions include (i) Do Colonial Revival style buildings perform better than other old buildings? (ii) Do the buildings consume additional electricity than typical and other old buildings? The research examined four case studies in Hartford County, Connecticut. The investigation explored comfort surveys, monitoring, collection of actual electricity usage, and assessed thermal indices using mathematical models. The average indoor temperature of 25.4 °C and relative humidity (RH) of 61.3% are reported. About 67% of the residents are thermally comfortable. The research noted significance between thermal sensation and other variables, excluding how occupants feel about the air movement. The average number of hours of temperature exceeds 28.0 °C and 30.0 °C marks for over 11.4% and 2.5% of the time, respectively, except in one of the buildings. The mean indoor temperatures are within the applicable bands of the adaptive comfort models. The averages of actual thermal sensation vote (TSV) ranged from 3.32 to 4.37 on a 7-point sensation scale. The mean neutral temperatures varied from 24.2–25.6 °C. The average monthly electricity bill is within the national average for residences in summer, excluding in August. The mean wet-bulb globe temperature (WBGT) of 21.1–22.3 °C and summer simmer index (SSI) of 30.1–32.4 °C are calculated as feasible bands for thermal indices in the buildings. The basements are more comfortable than other spaces within the case studies. The research outcomes can be used for future developments of Colonial Revival style and other similar buildings. The study recommends interventions such as retrofit to improve the performance of some existing Colonial Revival style buildings, especially the older ones that are less insulated with outdated equipment and appliances. Full article

(This article belongs to the Special Issue Buildings Energy Efficiency and Innovative Energy Systems)

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21 pages, 4475 KiB

Open AccessArticle

Integrated Performance Optimization of Higher Education Buildings Using Low-Energy Renovation Process and User Engagement

by Abdullahi Ahmed, Monica Mateo-Garcia, Andrew Arewa and Kassim Caratella

Energies 2021, 14(5), 1475; https://doi.org/10.3390/en14051475 - 08 Mar 2021

Cited by 6 | Viewed by 2538

Abstract

Building performance improvement through low-energy renovation traditionally involves building performance diagnostics of the existing building, technology evaluation, selection and implementation. Effective building performance diagnostics, post-retrofit assessment and user engagement are essential to deliver performance as well as achieving socio-economic and environmental benefits at every stage of the renovation project life cycle. User’s views are often ignored when renovating a building, causing sub-optimal energy performance, user comfort and wellbeing. This paper seeks to critically evaluate the low-energy renovation process and the role of user and stakeholder engagement in the strategic implementation of low-energy retrofit technologies for performance improvement of higher education buildings. The research focuses on renovation methodology, innovative materials/systems and end-user engagement throughout the renovation project phases (pre-renovation, the renovation process and post renovation). A mixed research method was adopted, which includes building performance modelling, monitoring and user evaluation questionnaires pre and post-renovation. The research is part of European Union (EU)-funded project, targeting 50% reduction in energy consumption using innovative materials and technologies in existing public buildings. The surveys allow comparative analysis of comfort levels and user satisfaction as an indicator of the efficacy of renovation measures. A new renovation process and user engagement framework was developed. The findings suggest that there is a direct relationship between retrofit intervention, improving energy performance of low-carbon buildings and the comfort of occupants. The technologies and strategies also appear to have different impacts on user satisfaction. Full article

(This article belongs to the Special Issue Buildings Energy Efficiency and Innovative Energy Systems)

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21 pages, 3927 KiB

Open AccessArticle

Decomposition Analysis of the Evolution of the Local Energy System as a Tool to Assess the Effect of Local Actions: Methodology and Example of Malmö, Sweden

by Isabel Azevedo and Vítor Leal

Energies 2021, 14(2), 461; https://doi.org/10.3390/en14020461 - 16 Jan 2021

Cited by 1 | Viewed by 1858

Abstract

This paper proposes the use of decomposition analysis to assess the effect of local energy-related actions towards climate change mitigation, and thus improve policy evaluation and planning at the local level. The assessment of the impact of local actions has been a challenge, even from a strictly technical perspective. This happens because the total change observed is the result of multiple factors influencing local energy-related greenhouse gas (GHG) emissions, many of them not even influenced by local authorities. A methodology was developed, based on a recently developed decomposition model, that disaggregates the total observed changes in the local energy system into multiple causes/effects (including local socio-economic evolution, technology evolution, higher-level governance frame and local actions). The proposed methodology, including the quantification of the specific effect associated with local actions, is demonstrated with the case study of the municipality of Malmö (Sweden) in the timeframe between 1990 and 2015. Full article

(This article belongs to the Special Issue Buildings Energy Efficiency and Innovative Energy Systems)

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26 pages, 2403 KiB

Open AccessArticle

Energy Policy Concerns, Objectives and Indicators: A Review towards a Framework for Effectiveness Assessment

by Dania Ortiz and Vítor Leal

Energies 2020, 13(24), 6533; https://doi.org/10.3390/en13246533 - 10 Dec 2020

Cited by 6 | Viewed by 2935

Abstract

This work presents a review that aims to characterize the policy evaluation practices regarding the public policies on energy, with a focus on the metrics: concerns, objectives, and indicators. As key novelty, emphasis was put into finding attributes and metrics that can be used to assess effectiveness, not only efficacy or efficiency. The concerns and objectives were organized into four categories: Institutional, Environmental, Economic, and Social. For every category, detailed and condensed concerns were identified. It was attempted to find indicators for every condensed concern, which resulted in 15 core indicators. Full article

(This article belongs to the Special Issue Buildings Energy Efficiency and Innovative Energy Systems)

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15 pages, 34103 KiB

Open AccessArticle

PoDIT: Portable Device for Indoor Temperature Stabilization: Concept and Theoretical Performance Assessment

by Vítor Leal and Raul Teixeira

Energies 2020, 13(22), 5982; https://doi.org/10.3390/en13225982 - 16 Nov 2020

Cited by 1 | Viewed by 1497

Abstract

This work introduces the concept of a new Portable Device for Indoor Temperature Stabilization (PoDIT), to be considered as a low-cost, quick and easy to implement remediation strategy when, for social, economic, or technical reasons, the improvement of the building envelope and/or the adoption of air conditioning are not possible. The main goal is to attenuate the maximum indoor temperature during summer and/or heat waves. The system, which is modular, consists of a certain mass of encaged phase change material (PCM) that stays indoors during the daytime and is transported to the outdoors (e.g., a balcony) during the night to discharge the heat accumulated during the daytime. Both natural convection and forced convection variants were considered. The results showed that, in the configurations and for the reference room and weather considered, the adopting 4 modules of the device can lead to reductions in the maximum room air temperature close to 3 °C, with natural convection. Adopting a fan to impose forced convection at the surfaces of the device can lead to temperature attenuations in excess of 4 °C, as it ensures full solid–liquid commuting and therefore optimal use of the PCM thermal storage capability. Full article

(This article belongs to the Special Issue Buildings Energy Efficiency and Innovative Energy Systems)

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Graphical abstract

16 pages, 2405 KiB

Open AccessArticle

A Study of Design Variables in Daylight and Energy Performance in Residential Buildings under Hot Climates

by Ali Mohammed AL-Dossary and Daeung Danny Kim

Energies 2020, 13(21), 5836; https://doi.org/10.3390/en13215836 - 09 Nov 2020

Cited by 10 | Viewed by 2867

Abstract

In Saudi Arabia, residential buildings are one of the major contributors to total energy consumption. Even though there are abundant natural resources, it is somewhat difficult to apply them to building designs, as design variables, due to slow progress and private issues in Saudi Arabia. Thus, the present study demonstrated the development of sustainable residential building design by examining the daylighting and energy performance with design variables. Focusing on the daylighting system, the design variables were chosen, including window-to-wall ratios (WWR), external shading devices, and types of glazing. The illuminance level by these design variables in a building was evaluated by using daylight metrics, such as spatial daylight autonomy and annual sunlight exposure. Moreover, the building energy consumption with these design variables was analyzed by using energy simulation. As a result, the daylighting was improved with the increase in WWRs and the tinted double glazing, while these design options can cause overheating in a residential building. Among types of glazing, the double pane windows with a low-E coating showed better energy performance. Based on the results, it is necessary to find the proper design variables that can balance the daylighting and energy performance in residential buildings in hot climates. Full article

(This article belongs to the Special Issue Buildings Energy Efficiency and Innovative Energy Systems)

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Graphical abstract

11 pages, 19852 KiB

Open AccessArticle

Thermal and Energy Performance Assessment of the Prefab Electric Ondol System for Floor Heating in a Residential Building

by Wongeun Lee, Taesub Lim and Daeung Danny Kim

Energies 2020, 13(21), 5723; https://doi.org/10.3390/en13215723 - 02 Nov 2020

Cited by 4 | Viewed by 2681

Abstract

In South Korea, radiant floor heating has been used from old housing to the recently constructed residential buildings, which is called “Ondol”. The Ondol system is generally a water-based system and it uses hot water as a heat medium provided by boilers fueled by natural gas. With great effort to reduce greenhouse gas emissions, electric Ondol panels have been increasingly applied to the recent residential buildings for floor heating. While the prefab electric Ondol panels were developed with the demand for dry construction method, the information about the prefab electric Ondol system is not sufficient. For the present study, the thermal performance of the prefab electric Ondol panels was investigated through field measurement. In addition, the heating energy and economic performance of the electric panel were compared with the conventional Ondol system. As a result, a significant surface temperature difference was observed. Moreover, the heating cost for the prefab electric Ondol system was more expensive than the conventional system, even though a heat loss was observed by the operation of the conventional system. Full article

(This article belongs to the Special Issue Buildings Energy Efficiency and Innovative Energy Systems)

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14 pages, 3947 KiB

Open AccessArticle

Evaluation of Daylight and Cooling Performance of Shading Devices in Residential Buildings in South Korea

by Taesub Lim, Woong Seog Yim and Daeung Danny Kim

Energies 2020, 13(18), 4749; https://doi.org/10.3390/en13184749 - 11 Sep 2020

Cited by 14 | Viewed by 2631

Abstract

Accounting for more than half of buildings in South Korea, the energy consumed by residential buildings has become a main concern and the cooing demand has rapidly increased. To reduce energy consumption, several passive and active design strategies have generally been applied. However, there has been an increasing demand for high window-to-wall ratios in residential buildings, it is imperative to block sunlight into a building effectively. Focusing on the reduction of cooling energy consumption in a residential building, the present study assessed the daylight and energy performance of shading devices. Among various types of shading devices, the Venetian blind, horizontal louver, light shelf, and egg-crate were selected. The illuminance levels in three different areas in a building were measured. In addition, the annual cooling energy consumption by these shading devices was investigated. As a result, both daylight and energy performance varied with different design options of these shading devices. Because of the slight performance difference among shading devices, the artificial loads of two best shading devices were compared. In sum, the egg-crate shading was the most proper shading device to block sunlight as well as reduce the cooling energy consumption effectively. Full article

(This article belongs to the Special Issue Buildings Energy Efficiency and Innovative Energy Systems)

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9 pages, 1769 KiB

Open AccessArticle

Heating Performance Analysis of an Air-to-Water Heat Pump Using Underground Air for Greenhouse Farming

by Taesub Lim, Yong-Kyu Baik and Daeung Danny Kim

Energies 2020, 13(15), 3863; https://doi.org/10.3390/en13153863 - 28 Jul 2020

Cited by 12 | Viewed by 2828

Abstract

As one of the main businesses in Jeju-do in South Korea, specialized local products are grown in greenhouses. For greenhouse farming, it is preferable to use geothermal heat pump systems for energy conservation because of the stable temperature of the ground. In the same manner, heat pumps using underground air is recommended for greenhouse farming since underground air can easily be obtained from porous volcanic rocks in Jeju-do. However, direct usage of the underground air is not feasible for planting in the greenhouse or livestock care because the underground air is relatively humid and its temperature is low. For the present study, the heating performance of an air-to-water heat pump which used underground air as a heat source for greenhouse farming during the winter was assessed through measurements. In addition, the economic impact of the air-to-water heat pump (AWHP) was compared with a conventional air heater. According to the results, an AWHP can save more than 70% of the total heating costs compared with a conventional air heater. In sum, the utilization of the air-to-water heat pump using underground air can have a positive impact on reducing energy consumption as well as provide direct economic benefits. Full article

(This article belongs to the Special Issue Buildings Energy Efficiency and Innovative Energy Systems)

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18 pages, 6177 KiB

Open AccessArticle

Total Solar Reflectance Optimization of the External Paint Coat in Residential Buildings Located in Mediterranean Climates

by Tiago Souto, Margarida Almeida, Vítor Leal, João Machado and Adélio Mendes

Energies 2020, 13(11), 2729; https://doi.org/10.3390/en13112729 - 29 May 2020

Cited by 6 | Viewed by 2371

Abstract

This work addresses the effect of the total solar reflectance (TSR) value of paints applied in residential buildings upon their thermal performance. A semi-detached residential building was modeled in the ESP-r software, and taken as the basis for parametric studies which assessed the effects of variations in (i) the TSR values; (ii) the thermal characteristics of the building envelope; (iii) the location/climate; and: (iv) the way how the indoor temperature is controlled. The parametric studies were used to find optimal TSR values for each combination of Location + Building envelope characteristics (mainly the existence of thermal insulation). It was concluded that paints having a carefully chosen TSR value lead to better indoor thermal temperatures if the buildings have no mechanical heating or cooling, or to energy savings of up to 32% if they do. Full article

(This article belongs to the Special Issue Buildings Energy Efficiency and Innovative Energy Systems)

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16 pages, 2492 KiB

Open AccessEditor’s ChoiceArticle

Thermochromic Paints on External Surfaces: Impact Assessment for a Residential Building through Thermal and Energy Simulation

by Vasco Granadeiro, Margarida Almeida, Tiago Souto, Vítor Leal, João Machado and Adélio Mendes

Energies 2020, 13(8), 1912; https://doi.org/10.3390/en13081912 - 14 Apr 2020

Cited by 17 | Viewed by 4899

Abstract

This work addresses the effect of using thermochromic paints in residential buildings. Two different thermochromic paint types were considered: One that changes properties through a step transition at a certain temperature, and another that changes properties in a gradual/linear manner throughout a temperature range. The studied building was a two-floor villa, virtually simulated through a digital model with and without thermal insulation, and considering thermochromic paints applied both on external walls and on the roof. The performance assessment was done through the energy use for heating and cooling (in conditioned mode), as well as in terms of the indoor temperature (in free-floating mode). Three different cities/climates were considered: Porto, Madrid, and Abu Dhabi. Results showed that energy savings up to 50.6% could be reached if the building is operated in conditioned mode. Conversely, when operated in free-floating mode, optimally selected thermochromic paints enable reductions up to 11.0 °C, during summertime, and an increase up to 2.7 °C, during wintertime. These results point out the great benefits of using optimally selected thermochromic paints for obtaining thermal comfort, and also the need to further develop stable and cost-effective thermochromic pigments for outdoor applications, as well as to test physical models in a real environment. Full article

(This article belongs to the Special Issue Buildings Energy Efficiency and Innovative Energy Systems)

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Review

Jump to: Research

21 pages, 457 KiB

Open AccessReview

A Review of the Measures and Instruments to Promote Efficiency and Renewable Energy in Domestic Water Heating

by Dania Ortiz, Vítor Leal and Isabel Azevedo

Energies 2020, 13(20), 5370; https://doi.org/10.3390/en13205370 - 15 Oct 2020

Cited by 1 | Viewed by 2224

Abstract

This paper identifies and characterizes the technical measures and policy instruments that can be used to promote energy efficiency and the use of renewable sources for domestic hot water (DHW). DHW presents a considerable potential for abatement of greenhouse gas emissions around the world. Measures were characterized in terms of level of transformation, impact and scope, among others. Policy instruments were characterized in terms of target groups, competences required for implementation, major challenges and nature of the instruments. A matrix showing the applicability of policy instruments per technical measure was derived, enabling policy makersto better choose articulated measures and policy instruments for their policy packs. Full article

(This article belongs to the Special Issue Buildings Energy Efficiency and Innovative Energy Systems)

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24 pages, 3520 KiB

Open AccessReview

A Review of the Relation between Household Indoor Temperature and Health Outcomes

by Fátima Lima, Paula Ferreira and Vítor Leal

Energies 2020, 13(11), 2881; https://doi.org/10.3390/en13112881 - 04 Jun 2020

Cited by 14 | Viewed by 3324

Abstract

This paper provides a review of research that addresses the relationship between indoor temperatures and health outcomes, taking into consideration studies that focus heat or cold exposure within the household context. It aims to extend previous research by considering both indoor temperatures from existing housing, and empirical studies that focus on energy efficiency measures and subsequent health impacts. To achieve this aim, a literature review was undertaken, combining engineering and health databases. The review established that, overall, inadequate indoor temperatures are associated with poor health status, whereas energy efficiency measures have been associated to improved indoor temperatures and occupant’s health namely regarding cardiovascular, respiratory and mental health disorders. These health conditions are among the most prevalent non-communicable diseases (NCD). The review also highlighted the need for more empirical studies with an extended timeframe to deal with climate change challenges. It underlined the potential advantages of the convergence between health and energy efficiency studies, for better modelling and planning. Full article

(This article belongs to the Special Issue Buildings Energy Efficiency and Innovative Energy Systems)

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