Energies

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16 pages, 8033 KiB

Open AccessArticle

Experimental Evaluation of the Heat Balance of an Interactive Glass Wall in A Heating Season

by Jerzy Szyszka

Energies 2020, 13(3), 632; https://doi.org/10.3390/en13030632 - 3 Feb 2020

Cited by 11 | Viewed by 5637

The paper presents an evaluation of the energy efficiency of an interactive glass wall (IGW) prototype. It is a design analogous to Trombe wall. It is capable of giving out the solar radiation heat gains after the sunset. It responds interactively to solar [...] Read more.

The paper presents an evaluation of the energy efficiency of an interactive glass wall (IGW) prototype. It is a design analogous to Trombe wall. It is capable of giving out the solar radiation heat gains after the sunset. It responds interactively to solar exposure and temperature conditions, regulating the thermal resistance adequately to the requirements. The evaluation of the efficiency of the IGW was based on the analysis of density of heat flux measured on the inner surface of the wall. The experiments were conducted in field conditions using a test chamber of regulated air temperature. The identified parameters of solar energy losses and efficiency enable the IGW heat balance in a heating season in selected climatic conditions to be predicted. In the present paper the IGW heat balance is calculated for the climate in Poland. The calculations proved that the gains of the heat absorbed from solar radiation wall overweigh the losses. Full article

(This article belongs to the Special Issue Innovative Technologies for Buildings Energy Efficiency and NZEB Targets)

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39 pages, 17497 KiB

Open AccessArticle

Building Energy Performance Analysis: An Experimental Validation of an In-House Dynamic Simulation Tool through a Real Test Room

by Giovanni Barone, Annamaria Buonomano, Cesare Forzano and Adolfo Palombo

Energies 2019, 12(21), 4107; https://doi.org/10.3390/en12214107 - 28 Oct 2019

Cited by 33 | Viewed by 5238

Abstract

This paper focuses on the experimental validation of a building energy performance simulation tool by means of a comparative analysis between numerical results and measurements obtained on a real test room. The empirical tests were carried out for several months under variable weather [...] Read more.

This paper focuses on the experimental validation of a building energy performance simulation tool by means of a comparative analysis between numerical results and measurements obtained on a real test room. The empirical tests were carried out for several months under variable weather conditions and in free-floating indoor temperature regime (switched off HVAC system). Measurements were exploited for validating an in-house simulation tool, implemented in MatLab and called DETECt, developed for dynamically assessing the energy performance of buildings. Results show that simulated indoor air and surface room temperatures resulted in very good agreement with the corresponding experimental data; the detected differences were often lower than 0.5 °C and almost always lower than 1 °C. Very low mean absolute and percentage errors were always achieved. In order to show the capabilities of the developed simulation tool, a suitable case study focused on innovative solar radiation high-reflective coatings, and infrared low-emissivity materials is also presented. The performance of these coatings and materials was investigated through a comparative analysis conducted to evaluate their heating and cooling energy saving potentials. Simulation results, obtained for the real test cell considered as equipped with such innovative coatings and material, show that for the weather zone of Naples a 5% saving is obtained both in summer and in winter by simultaneously adopting a high-reflectance coating and a low- emissivity plaster for roof/external walls and interior walls, respectively. Full article

(This article belongs to the Special Issue Innovative Technologies for Buildings Energy Efficiency and NZEB Targets)

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26 pages, 5878 KiB

Open AccessArticle

Evaluation of Energy and Daylight Performance of Old Office Buildings in South Korea with Curtain Walls Remodeled Using Polymer Dispersed Liquid Crystal (PDLC) Films

by Myunghwan Oh, Chulsung Lee, Jaesung Park, Kwangseok Lee and Sungho Tae

Energies 2019, 12(19), 3679; https://doi.org/10.3390/en12193679 - 26 Sep 2019

Cited by 27 | Viewed by 6760

Abstract

Globally, energy standards for new buildings are being reinforced to improve energy efficiency, and remodeling policies are being promoted for old buildings. The South Korean Government is promoting green remodeling projects, and focusing on research and product development to improve the performance of [...] Read more.

Globally, energy standards for new buildings are being reinforced to improve energy efficiency, and remodeling policies are being promoted for old buildings. The South Korean Government is promoting green remodeling projects, and focusing on research and product development to improve the performance of old windows and curtain walls. In line with this, the present study proposes two remodeling methods using polymer dispersed liquid crystal (PDLC) films, which can adjust solar radiation for old office buildings. In addition, energy efficiency improvement and daylight performance according to remodeling were analyzed. Attaching PDLC films to the glass of old curtain walls was analyzed; this can reduce heating and cooling energy, reduce the annual discomfort glare occurrence rate, and increase the annual indoor appropriate illuminance ratio. Furthermore, producing a window by laminating a PDLC film between two sheets of glass and putting it over the existing curtain wall was also analyzed; this can reduce annual building energy consumption and the annual discomfort glare occurrence rate, and improve the annual indoor appropriate illuminance ratio. Therefore, PDLC film is expected to be applicable as a next-generation green remodeling material because using it in remodeling can improve energy efficiency of old office buildings and indoor daylight performance. Full article

(This article belongs to the Special Issue Innovative Technologies for Buildings Energy Efficiency and NZEB Targets)

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16 pages, 6316 KiB

Open AccessArticle

Energy and Luminous Performance Investigation of an OPV/ETFE Glazing Element for Building Integration

by Álex Moreno, Daniel Chemisana, Rodolphe Vaillon, Alberto Riverola and Alejandro Solans

Energies 2019, 12(10), 1870; https://doi.org/10.3390/en12101870 - 16 May 2019

Cited by 18 | Viewed by 4595

Abstract

The combination of architectural membranes such as ethylene tetrafluoroethylene (ETFE) foils and organic photovoltaic (OPV) cells offers a wide range of possibilities for building integration applications. This is due to their flexibility, free-shape, variable color and semitransparency, light weight, cost-effectivity, and low environmental [...] Read more.

The combination of architectural membranes such as ethylene tetrafluoroethylene (ETFE) foils and organic photovoltaic (OPV) cells offers a wide range of possibilities for building integration applications. This is due to their flexibility, free-shape, variable color and semitransparency, light weight, cost-effectivity, and low environmental impact. In addition, electrical generation is provided. Four configurations of ETFE foils designed to be integrated onto a south façade glazing element were studied for two representative European locations with different climatic conditions: Barcelona and Paris. These configurations comprise a reference one based on a double ETFE foil with a 10 mm air gap in between, and the other three incorporate on the inner ETFE foil either OPV cells covering 50% or 100% of its surface or a shading pattern printed on it covering 50% of its surface. Results show that, in terms of energy, the configuration with higher OPV coverage area is the one achieving the lowest net energy consumption in both locations. However, when looking at the illumination comfort this option results in insufficient illumination levels. Therefore, a tradeoff strategy balancing energy performance and illumination comfort conditions is necessary. Based on that, the best solution found for both cities is the configuration integrating OPV cells covering 50% of the glazing area and for a window to wall ratio of 0.45. Full article

(This article belongs to the Special Issue Innovative Technologies for Buildings Energy Efficiency and NZEB Targets)

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19 pages, 4636 KiB

Open AccessArticle

Long-Term Monitoring of Sensible Thermal Storage in an Extremely Cold Region

by Getu Hailu, Philip Hayes and Mark Masteller

Energies 2019, 12(9), 1821; https://doi.org/10.3390/en12091821 - 13 May 2019

Cited by 10 | Viewed by 4181

Abstract

We present more than one-year of monitoring results from a thermal energy storage system located in a very cold place with a long winter season. The studied house is in Palmer city, Alaska (~62° N, ~149° W). The house is equipped with solar [...] Read more.

We present more than one-year of monitoring results from a thermal energy storage system located in a very cold place with a long winter season. The studied house is in Palmer city, Alaska (~62° N, ~149° W). The house is equipped with solar PV for electricity production and solar thermal collectors which were linked to a sensible thermal energy storage system which is underneath the house’s normally unoccupied garage and storage space. Sensors were installed in the thermal storage and solar thermal collector array to monitor system temperatures. In addition, TRNSYS was used for numerical simulation and the results were compared to experimental ones. The maximum observed garage ambient temperature was ~28 °C while the simulated maximum ambient garage temperature was found to be ~22 °C. Results indicate that seasonal solar thermal storages are viable options for reducing the cost of energy in a region with extended freezing periods. This is significant for Alaska where the cost of energy is 3–5 times the national average. Full article

(This article belongs to the Special Issue Innovative Technologies for Buildings Energy Efficiency and NZEB Targets)

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22 pages, 2970 KiB

Open AccessArticle

Cost-Benefit Analysis of Hybrid Photovoltaic/Thermal Collectors in a Nearly Zero-Energy Building

by Paolo Conti, Eva Schito and Daniele Testi

Energies 2019, 12(8), 1582; https://doi.org/10.3390/en12081582 - 25 Apr 2019

Cited by 19 | Viewed by 5309

Abstract

This paper analyzes the use of hybrid photovoltaic/thermal (PVT) collectors in nearly zero-energy buildings (NZEBs). We present a design methodology based on the dynamic simulation of the whole energy system, which includes the building energy demand, a reversible heat pump as generator, the [...] Read more.

This paper analyzes the use of hybrid photovoltaic/thermal (PVT) collectors in nearly zero-energy buildings (NZEBs). We present a design methodology based on the dynamic simulation of the whole energy system, which includes the building energy demand, a reversible heat pump as generator, the thermal storage, the power exchange with the grid, and both thermal and electrical energy production by solar collectors. An exhaustive search of the best equipment sizing and design is performed to minimize both the total costs and the non-renewable primary energy consumption over the system lifetime. The results show that photovoltaic/thermal technology reduces the non-renewable primary energy consumption below the nearly zero-energy threshold value, assumed as 15 kWh/(m²·yr), also reducing the total costs with respect to a non-solar solution (up to 8%). As expected, several possible optimal designs exist, with an opposite trend between energy savings and total costs. In all these optimal configurations, we figure out that photovoltaic/thermal technology favors the production of electrical energy with respect to the thermal one, which mainly occurs during the summer to meet the domestic hot water requirements and lower the temperature of the collectors. Finally, we show that, for a given solar area, photovoltaic/thermal technology leads to a higher reduction of the non-renewable primary energy and to a higher production of solar thermal energy with respect to a traditional separate production employing photovoltaic (PV) modules and solar thermal (ST) collectors. Full article

(This article belongs to the Special Issue Innovative Technologies for Buildings Energy Efficiency and NZEB Targets)

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18 pages, 17211 KiB

Open AccessArticle

Assessing the Potentiality of Animal Fat Based-Bio Phase Change Materials (PCM) for Building Applications: An Innovative Multipurpose Thermal Investigation

by Claudia Fabiani, Anna Laura Pisello, Marco Barbanera, Luisa F. Cabeza and Franco Cotana

Energies 2019, 12(6), 1111; https://doi.org/10.3390/en12061111 - 21 Mar 2019

Cited by 33 | Viewed by 4991

Abstract

In recent years, the implementation of novel solutions aimed at improving thermal energy storage (TES) capability to both energy technologies and building-integrated systems has gained increasing attention. In particular, the application of phase change materials (PCM) is currently gathering worldwide acknowledgment. In this [...] Read more.

In recent years, the implementation of novel solutions aimed at improving thermal energy storage (TES) capability to both energy technologies and building-integrated systems has gained increasing attention. In particular, the application of phase change materials (PCM) is currently gathering worldwide acknowledgment. In this work, the potential of animal fat as a novel bio-based PCM having transition temperature around the ambient temperature is assessed by means of thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and extensive temperature monitoring. Results from the TGA showed the differential degradation of the main components of the animal fat during the heating phase, where three different decomposition steps could be noticed. The thermal monitoring and the DSC analysis demonstrated the promising thermal performance of the material, which showed an interesting double transition range globally associated to a melting enthalpy of about 28.94 kJ·kg

^{- 1}

. The obtained results demonstrate the promising thermophysical properties of the animal fat blend, which can be considered as a low-cost, biocompatible PCM, particularly with potential application in passive building envelope applications for a wide range of temperature boundary conditions. Full article

(This article belongs to the Special Issue Innovative Technologies for Buildings Energy Efficiency and NZEB Targets)

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19 pages, 5593 KiB

Open AccessArticle

Exploring the Interplay between CAD and FreeFem++ as an Energy Decision-Making Tool for Architectural Design

by Juan Rojas-Fernández, Carmen Galán-Marín, Carlos Rivera-Gómez and Enrique D. Fernández-Nieto

Energies 2018, 11(10), 2665; https://doi.org/10.3390/en11102665 - 7 Oct 2018

Cited by 7 | Viewed by 5338

Abstract

The energy modelling software tools commonly used for architectural purposes do not allow a straightforward real-time implementation within the architectural design programs. In addition, the surrounding exterior spaces of the building, including the inner courtyards, hardly present a specific treatment distinguishing these spaces [...] Read more.

The energy modelling software tools commonly used for architectural purposes do not allow a straightforward real-time implementation within the architectural design programs. In addition, the surrounding exterior spaces of the building, including the inner courtyards, hardly present a specific treatment distinguishing these spaces from the general external temperature in the thermal simulations. This is a clear disadvantage when it comes to streamlining the design process in relation to the whole-building energy optimization. In this context, the present study aims to demonstrate the advantages of the FreeFem++ open source program for performing simulations in architectural environments. These simulations include microclimate tests that describe the interactions between a building architecture and its local exterior. The great potential of this mathematical tool can be realized through its complete system integration within CAD (Computer-Aided Design) software such as SketchUp or AutoCAD. In order to establish the suitability of FreeFem++ for the performance of simulations, the most widely employed energy simulation tools able to consider a proposed architectural geometry in a specific environment are compared. On the basis of this analysis, it can be concluded that FreeFem++ is the only program displaying the best features for the thermal performance simulation of these specific outdoor spaces, excluding the currently unavailable easy interaction with architectural drawing programs. The main contribution of this research is, in fact, the enhancement of FreeFem++ usability by proposing a simple intuitive method for the creation of building geometries and their respective meshing (pre-processing). FreeFem++ is also considered a tool for data analysis (post-processing) able to help engineers and architects with building energy-efficiency-related tasks. Full article

(This article belongs to the Special Issue Innovative Technologies for Buildings Energy Efficiency and NZEB Targets)

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