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Special Issue "Energy Efficient Building Design and Operation 2014"

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A special issue of Energies (ISSN 1996-1073).

Deadline for manuscript submissions: closed (15 June 2014)

Special Issue Editor

Guest Editor
Dr. Stephen Treado (Website)

Department of Architectural Engineering, The Pennsylvania State University, 104 Engineering Unit A, University Park, PA 16802, USA
Interests: high performance buildings; building control systems; energy efficiency; renewable energy; optimization

Special Issue Information

Dear Colleagues,

The focus of this Special Issue will be on the design, construction and operation of high performance buildings. High performance buildings are those that provide all the required building services for occupants in an energy and cost efficient manner. Contributions are being solicited for research or survey papers describing building materials, components and systems that enable or provide for the efficient use of energy while maintaining a productive indoor environment for building occupants. Possible topics include:

  • Ÿbuilding envelope design
  • Ÿselection and operation of mechanical equipment and thermal machinery
  • space conditioning systems
  • indoor environmental quality
  • control system design and operation
  • building simulation
  • model predictive control
  • smart buildings
  • renewable energy systems and systems integration

Other areas of interest include enhanced occupant feedback and interactions, adaptive control, dynamic building response and optimization of building design and operation.

Dr. Stephen Treado
Guest Editor

Submission

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Energies is an international peer-reviewed Open Access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1400 CHF (Swiss Francs).

Keywords

  • Ÿ  buildings
  • Ÿ  control systems
  • Ÿ  energy efficiency
  • Ÿ  high performance buildings
  • Ÿ  IEQ
  • Ÿ  model predictive control
  • Ÿ  simulation
  • Ÿ  thermal comfort

Published Papers (20 papers)

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Research

Open AccessArticle Design Optimization of Heat Wheels for Energy Recovery in HVAC Systems
Energies 2014, 7(11), 7348-7367; doi:10.3390/en7117348
Received: 31 July 2014 / Revised: 13 September 2014 / Accepted: 4 November 2014 / Published: 14 November 2014
Cited by 3 | PDF Full-text (1745 KB) | HTML Full-text | XML Full-text
Abstract
Air to air heat exchangers play a crucial role in mechanical ventilation equipment, due to the potential primary energy savings both in case of refurbishment of existing buildings or in case of new ones. In particular, interest in heat wheels is increasing [...] Read more.
Air to air heat exchangers play a crucial role in mechanical ventilation equipment, due to the potential primary energy savings both in case of refurbishment of existing buildings or in case of new ones. In particular, interest in heat wheels is increasing due to their low pressure drop and high effectiveness. In this paper a detailed optimization of design parameters of heat wheels is performed in order to maximize sensible effectiveness and to minimize pressure drop. The analysis is carried out through a one dimensional lumped parameters heat wheel model, which solves heat and mass transfer equations, and through appropriate correlations to estimate pressure drop. Simulation results have been compared with experimental data of a heat wheel tested in specific facilities, and good agreement is attained. The device optimization is performed through the variation of main design parameters, such as heat wheel length, channel base, height and thickness and for different operating conditions, namely the air face velocity and the revolution speed. It is shown that the best configurations are achieved with small channel thickness and, depending on the required sensible effectiveness, with appropriate values of wheel length and channel base and height. Full article
(This article belongs to the Special Issue Energy Efficient Building Design and Operation 2014)
Open AccessArticle Evaluation of Artificial Neural Network-Based Temperature Control for Optimum Operation of Building Envelopes
Energies 2014, 7(11), 7245-7265; doi:10.3390/en7117245
Received: 15 June 2014 / Revised: 27 August 2014 / Accepted: 28 October 2014 / Published: 12 November 2014
Cited by 1 | PDF Full-text (761 KB) | HTML Full-text | XML Full-text
Abstract
This study aims at developing an indoor temperature control method that could provide comfortable thermal conditions by integrating heating system control and the opening conditions of building envelopes. Artificial neural network (ANN)-based temperature control logic was developed for the control of heating [...] Read more.
This study aims at developing an indoor temperature control method that could provide comfortable thermal conditions by integrating heating system control and the opening conditions of building envelopes. Artificial neural network (ANN)-based temperature control logic was developed for the control of heating systems and openings at the building envelopes in a predictive and adaptive manner. Numerical comparative performance tests for the ANN-based temperature control logic and conventional non-ANN-based counterpart were conducted for single skin enveloped and double skin enveloped buildings after the simulation program was validated by comparing the simulation and the field measurement results. Analysis results revealed that the ANN-based control logic improved the indoor temperature environment with an increased comfortable temperature period and decreased overshoot and undershoot of temperatures outside of the operating range. The proposed logic did not show significant superiority in energy efficiency over the conventional logic. The ANN-based temperature control logic was able to maintain the indoor temperature more comfortably and with more stability within the operating range due to the predictive and adaptive features of ANN models. Full article
(This article belongs to the Special Issue Energy Efficient Building Design and Operation 2014)
Open AccessArticle A Heuristic Rule-Based Passive Design Decision Model for Reducing Heating Energy Consumption of Korean Apartment Buildings
Energies 2014, 7(11), 6897-6929; doi:10.3390/en7116897
Received: 3 July 2014 / Revised: 8 August 2014 / Accepted: 16 October 2014 / Published: 29 October 2014
PDF Full-text (2500 KB) | HTML Full-text | XML Full-text
Abstract
This research presents an evaluative energy model for estimating the energy efficiency of the design choices of architects and engineers in the early design phase. We analyze the effects of various parameters with different characteristics in various combinations for building energy consumption. [...] Read more.
This research presents an evaluative energy model for estimating the energy efficiency of the design choices of architects and engineers in the early design phase. We analyze the effects of various parameters with different characteristics in various combinations for building energy consumption. With this analysis, we build a database that identifies a set of heuristic rules for energy-efficient building design to facilitate the design of sustainable apartment housing. Perturbation studies are based on a sensitivity analysis used to identify the thermal influence of the input design parameters on various simulation outputs and compare the results to a reference case. Energy sensitivity weight factors are obtained from an extensive sensitivity study using building energy simulations. The results of the energy sensitivity study summarized in a set of heuristic rules for evaluating architectural features are estimated through case studies of Korean apartment buildings. This study offers valuable guidelines for developing energy-efficient residential housing in Korea and will help architects in considering appropriate design schemes and provide a ready reference to generalized test cases for both architects and engineers so that they can zero in on a set of effective design solutions. Full article
(This article belongs to the Special Issue Energy Efficient Building Design and Operation 2014)
Open AccessArticle A New System to Estimate and Reduce Electrical Energy Consumption of Domestic Hot Water in Spain
Energies 2014, 7(11), 6837-6855; doi:10.3390/en7116837
Received: 16 May 2014 / Revised: 7 October 2014 / Accepted: 17 October 2014 / Published: 24 October 2014
PDF Full-text (961 KB) | HTML Full-text | XML Full-text
Abstract
Energy consumption rose about 28% over the 2001 to 2011 period in the Spanish residential sector. In this environment, domestic hot water (DHW) represents the second highest energy demand. There are several methodologies to estimate DHW consumption, but each methodology uses different [...] Read more.
Energy consumption rose about 28% over the 2001 to 2011 period in the Spanish residential sector. In this environment, domestic hot water (DHW) represents the second highest energy demand. There are several methodologies to estimate DHW consumption, but each methodology uses different inputs and some of them are based on obsolete data. DHW energy consumption estimation is a key tool to plan modifications that could enhance this consumption and we decided to update the methodologies. We studied DHW consumption with data from 10 apartments in the same building during 18 months. As a result of the study, we updated one chosen methodology, adapting it to the current situation. One of the challenges to improve efficiency of DHW use is that most of people are not aware of how it is consumed in their homes. To help this information to reach consumers, we developed a website to allow users to estimate the final electrical energy needed for DHW. The site uses three estimation methodologies and chooses the best fit based on information given by the users. Finally, the application provides users with recommendations and tips to reduce their DHW consumption while still maintaining the desired comfort level. Full article
(This article belongs to the Special Issue Energy Efficient Building Design and Operation 2014)
Open AccessArticle Comparative Study of Two Daylighting Analysis Methods with Regard to Window Orientation and Interior Wall Reflectance
Energies 2014, 7(9), 5825-5846; doi:10.3390/en7095825
Received: 8 May 2014 / Revised: 8 August 2014 / Accepted: 2 September 2014 / Published: 5 September 2014
Cited by 4 | PDF Full-text (2709 KB) | HTML Full-text | XML Full-text
Abstract
The accuracy and speed of the daylighting analysis developed for use in EnergyPlus is better than its predecessors. In EnergyPlus, the detailed method uses the Split-flux algorithm whereas the DElight method uses the Radiosity algorithm. Many existing studies have addressed the two [...] Read more.
The accuracy and speed of the daylighting analysis developed for use in EnergyPlus is better than its predecessors. In EnergyPlus, the detailed method uses the Split-flux algorithm whereas the DElight method uses the Radiosity algorithm. Many existing studies have addressed the two methods, either individually or compared with other daylight analysis methods like Ray tracing but still there is lack of detailed comparative study of these two methods. Our previous studies show that the Split-flux method overestimates the illuminance, especially for the areas away from the window. The Radiosity method has the advantage of accurately predicting this illuminance because of how it deals with the diffuse light. For this study, the EnergyPlus model, which has been calibrated using data measured in a real building in previous studies, has also been used. The calibrated model has a south oriented window only. This model is then used to analyze the interior illuminance inside the room for north, west and east orientation of the window by rotating the model and by changing the wall reflectance of the model with south oriented window. Direct and diffuse component of the illuminance as well as the algorithms have been compared for a detailed analysis. Full article
(This article belongs to the Special Issue Energy Efficient Building Design and Operation 2014)
Open AccessArticle Evaluation of Mechanically and Adhesively Fixed External Insulation Systems Using Vacuum Insulation Panels for High-Rise Apartment Buildings
Energies 2014, 7(9), 5764-5786; doi:10.3390/en7095764
Received: 12 June 2014 / Revised: 19 August 2014 / Accepted: 26 August 2014 / Published: 3 September 2014
Cited by 3 | PDF Full-text (2160 KB) | HTML Full-text | XML Full-text
Abstract
Buildings account for a significant portion of a nation’s total energy consumption. To meet the global demand for greater energy efficiency, many countries are drastically strengthening insulation regulations for buildings. Thus, dramatically thicker wall insulation may be required, which can adversely affect [...] Read more.
Buildings account for a significant portion of a nation’s total energy consumption. To meet the global demand for greater energy efficiency, many countries are drastically strengthening insulation regulations for buildings. Thus, dramatically thicker wall insulation may be required, which can adversely affect the value of a building by reducing its effective floor area. Hence, high-performance insulation materials, such as vacuum insulation panels (VIPs), are of interest in building design. In this study, external insulation systems using VIPs were examined to determine their effectiveness in high-performance insulation systems for high-rise apartment buildings. A variety of mechanically and adhesively fixed external insulation systems with various insulation layer compositions have been proposed as alternatives to conventional internal insulation systems. The performance of conventional insulation systems and the proposed alternatives were compared through three-dimensional heat transfer simulations. The construction costs and the ease of installation of the various systems were also compared. The overall performance of each alternative in terms of the insulation performance, construction costs, and ease of installation was thus evaluated to determine the most effective alternative. Full article
(This article belongs to the Special Issue Energy Efficient Building Design and Operation 2014)
Open AccessArticle Finite Element Method Modeling of Sensible Heat Thermal Energy Storage with Innovative Concretes and Comparative Analysis with Literature Benchmarks
Energies 2014, 7(8), 5291-5316; doi:10.3390/en7085291
Received: 17 June 2014 / Revised: 22 July 2014 / Accepted: 11 August 2014 / Published: 15 August 2014
Cited by 3 | PDF Full-text (3094 KB) | HTML Full-text | XML Full-text
Abstract
Efficient systems for high performance buildings are required to improve the integration of renewable energy sources and to reduce primary energy consumption from fossil fuels. This paper is focused on sensible heat thermal energy storage (SHTES) systems using solid media and numerical [...] Read more.
Efficient systems for high performance buildings are required to improve the integration of renewable energy sources and to reduce primary energy consumption from fossil fuels. This paper is focused on sensible heat thermal energy storage (SHTES) systems using solid media and numerical simulation of their transient behavior using the finite element method (FEM). Unlike other papers in the literature, the numerical model and simulation approach has simultaneously taken into consideration various aspects: thermal properties at high temperature, the actual geometry of the repeated storage element and the actual storage cycle adopted. High-performance thermal storage materials from the literatures have been tested and used here as reference benchmarks. Other materials tested are lightweight concretes with recycled aggregates and a geopolymer concrete. Their thermal properties have been measured and used as inputs in the numerical model to preliminarily evaluate their application in thermal storage. The analysis carried out can also be used to optimize the storage system, in terms of thermal properties required to the storage material. The results showed a significant influence of the thermal properties on the performances of the storage elements. Simulation results have provided information for further scale-up from a single differential storage element to the entire module as a function of material thermal properties. Full article
(This article belongs to the Special Issue Energy Efficient Building Design and Operation 2014)
Figures

Open AccessArticle Dialectic Form Finding of Passive and Adaptive Shading Enclosures
Energies 2014, 7(8), 5201-5220; doi:10.3390/en7085201
Received: 9 June 2014 / Revised: 17 July 2014 / Accepted: 5 August 2014 / Published: 13 August 2014
Cited by 4 | PDF Full-text (1876 KB) | HTML Full-text | XML Full-text
Abstract
Form finding describes the process of finding a stable equilibrium shape for a system under a specific set of loads, for a set of boundary conditions and starting from an arbitrary initial geometry. However, form finding does not traditionally involve performance constraints [...] Read more.
Form finding describes the process of finding a stable equilibrium shape for a system under a specific set of loads, for a set of boundary conditions and starting from an arbitrary initial geometry. However, form finding does not traditionally involve performance constraints such as energy-related criteria. Dialectic form finding is an extension of the process integrating energy-related design aspects. In this paper, dialectic form finding is employed as an approach for designing high performance architectural systems, driven by solar radiation control and structural efficiency. Two applications of dialectic form found shading enclosure structures, a passive and an active one, are presented. The first application example is a site-specific outdoor shading structure. The structure is based on a louver system designed to provide protection from ultraviolet radiation over a pre-defined target only when required, promoting natural lighting and ventilation. The second application example is a shape-shifting modular façade system that adapts its opacity in response to environmental fluctuations. The system can thus improve the environmental performance of a building. Moreover, the system explores elastic deformations for shape changes, reducing actuation requirements. These examples highlight the potential of the dialectic form-finding strategy for the design of high performance architectural integrated structures. Full article
(This article belongs to the Special Issue Energy Efficient Building Design and Operation 2014)
Open AccessArticle An Economic and Environmental Assessment Model for Selecting the Optimal Implementation Strategy of Fuel Cell Systems—A Focus on Building Energy Policy
Energies 2014, 7(8), 5129-5150; doi:10.3390/en7085129
Received: 24 May 2014 / Revised: 8 July 2014 / Accepted: 5 August 2014 / Published: 12 August 2014
Cited by 7 | PDF Full-text (2818 KB) | HTML Full-text | XML Full-text
Abstract
Considerable effort is being made to reduce the primary energy consumption in buildings. As part of this effort, fuel cell systems are attracting attention as a new/renewable energy systems for several reasons: (i) distributed generation system; (ii) combined heat and power system; [...] Read more.
Considerable effort is being made to reduce the primary energy consumption in buildings. As part of this effort, fuel cell systems are attracting attention as a new/renewable energy systems for several reasons: (i) distributed generation system; (ii) combined heat and power system; and (iii) availability of various sources of hydrogen in the future. Therefore, this study aimed to develop an economic and environmental assessment model for selecting the optimal implementation strategy of the fuel cell system, focusing on building energy policy. This study selected two types of buildings (i.e., residential buildings and non-residential buildings) as the target buildings and considered two types of building energy policies (i.e., the standard of energy cost calculation and the standard of a government subsidy). This study established the optimal implementation strategy of the fuel cell system in terms of the life cycle cost and life cycle CO2 emissions. For the residential building, it is recommended that the subsidy level and the system marginal price level be increased. For the non-residential building, it is recommended that gas energy cost be decreased and the system marginal price level be increased. The developed model could be applied to any other country or any other type of building according to building energy policy. Full article
(This article belongs to the Special Issue Energy Efficient Building Design and Operation 2014)
Open AccessArticle Impact of Air Tightness on the Evaluation of Building Energy Performance in Lithuania
Energies 2014, 7(8), 4972-4987; doi:10.3390/en7084972
Received: 9 April 2014 / Revised: 11 July 2014 / Accepted: 22 July 2014 / Published: 4 August 2014
PDF Full-text (1686 KB) | HTML Full-text | XML Full-text
Abstract
In order to fulfil the European Energy Performance of Buildings Directive (EPBD) requirements for the reduction of energy consumption, European national requirements have been created for building envelope thermal properties and calculation methodology to determine if building energy efficiency is created. This [...] Read more.
In order to fulfil the European Energy Performance of Buildings Directive (EPBD) requirements for the reduction of energy consumption, European national requirements have been created for building envelope thermal properties and calculation methodology to determine if building energy efficiency is created. This is however not true in all methodologies. The necessity of building air tightness appears only for new A class buildings, and there are no requirements for air tightness for other building classes. Therefore, the aim of this work is to improve the methodology for the calculation of energy efficiency of buildings, while taking into account the air tightness of the buildings. In order to achieve this aim, the sum energy consumption of investigated buildings was calculated, energy efficiency classes were determined, air tightness of the buildings was measured, and reasons for insufficient air tightness were analyzed. Investigation results show that the average value of air tightness of A energy efficiency class buildings is 0.6 h−1. The results of other investigated buildings, corresponding to B and C energy efficiency classes, show insufficient air tightness (the average n50 value is 6 h−1); herewith, energy consumption for heating is higher than calculated, according to the energy efficiency methodology. This paper provides an energy performance evaluation scheme, under which performed evaluation of energy performance of buildings ensures high quality construction work, building durability, and the reliability of heat-loss calculations. Full article
(This article belongs to the Special Issue Energy Efficient Building Design and Operation 2014)
Open AccessArticle Research on Energy Saving Potential for Dedicated Ventilation Systems Based on Heat Recovery Technology
Energies 2014, 7(7), 4261-4280; doi:10.3390/en7074261
Received: 30 April 2014 / Revised: 6 June 2014 / Accepted: 19 June 2014 / Published: 2 July 2014
Cited by 1 | PDF Full-text (277 KB) | HTML Full-text | XML Full-text
Abstract
Research results have identified the use of heat pipe heat exchangers (HPHXs) for heat recovery as a way to reduce the pre-cooling and re-heating energy. This paper suggests decoupling dehumidification from cooling to reduce energy consumption. The feasible usage and the energy [...] Read more.
Research results have identified the use of heat pipe heat exchangers (HPHXs) for heat recovery as a way to reduce the pre-cooling and re-heating energy. This paper suggests decoupling dehumidification from cooling to reduce energy consumption. The feasible usage and the energy saving potential of heat pipe heat exchanger at the air handler dedicated in accomplishing this objective is investigated. In this paper a dedicated ventilation system combined with a HPHX to reduce energy consumption is tested and investigated under varying conditions by laboratory experiments. The energy saving potential and heat pipe (HP) effectiveness are tested and calculated under various outdoor conditions. The simulation and experimental results demonstrate that for all cases examined, the average HP effectiveness and energy savings have the same trend at various outdoor temperatures and Relative Humidity (RH) values. It has been found that the heat pipe can be applied to save over 60% energy for the air-conditioning operating hours. The reduction in overall energy is from 1.8% to 2.8% for the whole system. Therefore, the results confirm that the proposed set-up is useful for buildings to achieve intended energy saving objectives in subtropical climates where air-conditioning demand is highly variable. Full article
(This article belongs to the Special Issue Energy Efficient Building Design and Operation 2014)
Open AccessArticle Analysis of Occupants’ Visual Perception to Refine Indoor Lighting Environment for Office Tasks
Energies 2014, 7(7), 4116-4139; doi:10.3390/en7074116
Received: 27 April 2014 / Revised: 17 June 2014 / Accepted: 18 June 2014 / Published: 27 June 2014
Cited by 2 | PDF Full-text (1022 KB) | HTML Full-text | XML Full-text
Abstract
The combined effects of color temperature and illuminance in a small office on visual response and mood under various lighting conditions were examined in this study. Visual annoyance tests were conducted using a sample of 20 subjects in a full-scale mock-up test [...] Read more.
The combined effects of color temperature and illuminance in a small office on visual response and mood under various lighting conditions were examined in this study. Visual annoyance tests were conducted using a sample of 20 subjects in a full-scale mock-up test space. Computer and paper-based reading tasks were conducted for 500 lx and 750 lx illuminance levels under 3,000 K, 4,000 K and 6,500 K conditions. Two hypotheses were considered for the test in this study. The primary hypothesis was that visual perception is affected by the color temperatures of light sources. The secondary hypothesis was that better moods, such as relaxed and cozy feelings, are associated with low color temperatures given equal illuminance levels. The visual environment under the 3,000 K condition was characterized by glare and brightness, resulting in visual discomfort when target illuminance was higher than 500 lx. Occupants preferred 500 lx under the 6,500 K condition, and 500 lx and 750 lx under the 4,000 K condition, reporting better visual satisfaction when performing office tasks. Prediction models for visual comfort suggest that the less that subjects are visually bothered by light during tasks, the more visual comfort they feel. User satisfaction with light source color is critical for the prediction of visual comfort under different lighting conditions. Visual comfort was the most influential factor on mood. Lower color temperature was associated with better mood at lower illuminance levels, while higher color temperature was preferred at higher illuminance levels. Full article
(This article belongs to the Special Issue Energy Efficient Building Design and Operation 2014)
Open AccessArticle Novel Modeling and Control Strategies for a HVAC System Including Carbon Dioxide Control
Energies 2014, 7(6), 3599-3617; doi:10.3390/en7063599
Received: 17 February 2014 / Revised: 27 April 2014 / Accepted: 20 May 2014 / Published: 2 June 2014
Cited by 2 | PDF Full-text (1065 KB) | HTML Full-text | XML Full-text
Abstract
Conventional heating, ventilating, and air conditioning (HVAC) systems have traditionally used the temperature and the humidity ratio as the quantitative indices of comfort in a room. Recently, the carbon dioxide (CO2) concentration has also been recognized as having an important [...] Read more.
Conventional heating, ventilating, and air conditioning (HVAC) systems have traditionally used the temperature and the humidity ratio as the quantitative indices of comfort in a room. Recently, the carbon dioxide (CO2) concentration has also been recognized as having an important contribution to room comfort. This paper presents the modeling of an augmented HVAC system including CO2 concentration, and its control strategies. Because the proposed augmented HVAC system is multi-input multi-output (MIMO) and has no relative degree problem, the dynamic extension algorithm can be employed; then, a feedback linearization technique is applied. A linear-quadratic regulator (LQR) is designed to optimize control performance and to stabilize the proposed HVAC system. Simulation results are provided to validate the proposed system model, as well as its linearized control system. Full article
(This article belongs to the Special Issue Energy Efficient Building Design and Operation 2014)
Open AccessArticle A Boiler Room in a 600-Bed Hospital Complex: Study, Analysis, and Implementation of Energy Efficiency Improvements
Energies 2014, 7(5), 3282-3303; doi:10.3390/en7053282
Received: 8 April 2014 / Revised: 8 May 2014 / Accepted: 13 May 2014 / Published: 19 May 2014
PDF Full-text (1217 KB) | HTML Full-text | XML Full-text
Abstract
The aim of energy efficiency is to use less energy to provide the same service. In hospitals, energy efficiency offers a powerful and cost-effective tool to reduce greenhouse gas emissions, fuel consumption, and also running costs. Over a six-month period, the six [...] Read more.
The aim of energy efficiency is to use less energy to provide the same service. In hospitals, energy efficiency offers a powerful and cost-effective tool to reduce greenhouse gas emissions, fuel consumption, and also running costs. Over a six-month period, the six gas-fired boilers that provide both a hospital’s heat and hot water were monitored. Analysis of the data obtained led to several actions being implemented in the hospital boiler room control system to improve the efficiency of the heat production system. Comparative studies were conducted, during similar weather periods, of the performance of the hospital’s hot water production system before and after the controls were implemented. Results indicate that the control actions applied proved to be effective. Finally; the paper offers a financial; primary energy saving and CO2 reduction analysis that points to a 3,434.00 €/week savings in natural gas consumption; and a cut in CO2 emissions of 20.3 tons/week; as compared to the reference facility. Full article
(This article belongs to the Special Issue Energy Efficient Building Design and Operation 2014)
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Open AccessArticle Summer and Winter Effect of Innovative Cool Roof Tiles on the Dynamic Thermal Behavior of Buildings
Energies 2014, 7(4), 2343-2361; doi:10.3390/en7042343
Received: 30 January 2014 / Revised: 27 March 2014 / Accepted: 9 April 2014 / Published: 14 April 2014
Cited by 27 | PDF Full-text (1695 KB) | HTML Full-text | XML Full-text
Abstract
Cool roofs represent an acknowledged passive cooling technique to reduce building energy consumption for cooling and to mitigate urban heat island effects. This paper concerns the evaluation of the dynamic effect of new cool roof clay tiles on building thermal performance in [...] Read more.
Cool roofs represent an acknowledged passive cooling technique to reduce building energy consumption for cooling and to mitigate urban heat island effects. This paper concerns the evaluation of the dynamic effect of new cool roof clay tiles on building thermal performance in summer and winter conditions. To this end, these properties have been analyzed on traditional roof brick tiles through an indoor and outdoor two-year long continuous monitoring campaign set up in a residential building located in central Italy. The analysis and the cooperation with industrial companies producing brick tiles and reflective coatings allowed the production of a new tile with notable “cool roof” properties through the traditional industrial manufacturing path of such tiles. Notable results show that during summer the high reflection tiles are able to decrease the average external roof surface temperature by more than 10 °C and the indoor operative temperature by more than 3 °C. During winter the average external surface temperature is lower with high reflection tiles by about 1 °C. Singular optic-thermal phenomena are registered while evaluating the dynamics of the cool roof effect. Interesting findings show how the sloped cool roof application could suggest further considerations about the dynamic effect of cool roofs. Full article
(This article belongs to the Special Issue Energy Efficient Building Design and Operation 2014)
Open AccessArticle Window Material Daylighting Performance Assessment Algorithm: Comparing Radiosity and Split-Flux Methods
Energies 2014, 7(4), 2362-2376; doi:10.3390/en7042362
Received: 2 March 2014 / Revised: 2 April 2014 / Accepted: 8 April 2014 / Published: 14 April 2014
Cited by 4 | PDF Full-text (1028 KB) | HTML Full-text | XML Full-text
Abstract
Windows are the primary aperture to introduce solar radiation to the interior space of a building. This experiment explores the use of EnergyPlus software for analyzing the illuminance level on the floor of a room with reference to its distance from the [...] Read more.
Windows are the primary aperture to introduce solar radiation to the interior space of a building. This experiment explores the use of EnergyPlus software for analyzing the illuminance level on the floor of a room with reference to its distance from the window. For this experiment, a double clear glass window has been used. The preliminary modelling in EnergyPlus showed a consistent result with the experimentally monitored data in real time. EnergyPlus has two mainly used daylighting algorithms: DElight method employing radiosity technique and Detailed method employing split-flux technique. Further analysis for illuminance using DElight and Detailed methods showed significant difference in the results. Finally, we compared the algorithms of the two analysis methods in EnergyPlus. Full article
(This article belongs to the Special Issue Energy Efficient Building Design and Operation 2014)
Open AccessArticle Influence of Three Dynamic Predictive Clothing Insulation Models on Building Energy Use, HVAC Sizing and Thermal Comfort
Energies 2014, 7(4), 1917-1934; doi:10.3390/en7041917
Received: 25 January 2014 / Revised: 5 March 2014 / Accepted: 19 March 2014 / Published: 27 March 2014
Cited by 3 | PDF Full-text (1270 KB) | HTML Full-text | XML Full-text
Abstract
In building energy simulation, indoor thermal comfort condition, energy use and equipment size are typically calculated based on the assumption that the clothing insulation is equal to a constant value of 0.5 clo during the cooling season and 1.0 clo during the [...] Read more.
In building energy simulation, indoor thermal comfort condition, energy use and equipment size are typically calculated based on the assumption that the clothing insulation is equal to a constant value of 0.5 clo during the cooling season and 1.0 clo during the heating season. The assumption is not reflected in practice and thus it may lead to errors. In reality, occupants frequently adjust their clothing depending on the thermal conditions, as opposed to the assumption of constant clothing values above, indicating that the clothing insulation variation should be captured in building simulation software to obtain more reliable and accurate results. In this study, the impact of three newly developed dynamic clothing insulation models on the building simulation is quantitatively assessed using the detailed whole-building energy simulation program, EnergyPlus version 6.0. The results showed that when the heating ventilation and air conditioning system (HVAC) is controlled based on indoor temperature the dynamic clothing models do not affect indoor operative temperatures, energy consumption and equipment sizing. When the HVAC is controlled based on the PMV model the use of a fixed clothing insulation during the cooling (0.5 clo) and heating (1.0 clo) season leads to the incorrect estimation of the indoor operative temperatures, energy consumption and equipment sizing. The dynamic clothing models significantly (p < 0.0001) improve the ability of energy simulation tools to assess thermal comfort. The authors recommend that the dynamic clothing models should be implemented in dynamic building energy simulation software such as EnergyPlus. Full article
(This article belongs to the Special Issue Energy Efficient Building Design and Operation 2014)
Open AccessArticle Short-Term Electrical Peak Demand Forecasting in a Large Government Building Using Artificial Neural Networks
Energies 2014, 7(4), 1935-1953; doi:10.3390/en7041935
Received: 7 February 2014 / Revised: 14 March 2014 / Accepted: 24 March 2014 / Published: 27 March 2014
PDF Full-text (496 KB) | HTML Full-text | XML Full-text
Abstract
The power output capacity of a local electrical utility is dictated by its customers’ cumulative peak-demand electrical consumption. Most electrical utilities in the United States maintain peak-power generation capacity by charging for end-use peak electrical demand; thirty to seventy percent of an [...] Read more.
The power output capacity of a local electrical utility is dictated by its customers’ cumulative peak-demand electrical consumption. Most electrical utilities in the United States maintain peak-power generation capacity by charging for end-use peak electrical demand; thirty to seventy percent of an electric utility’s bill. To reduce peak demand, a real-time energy monitoring system was designed, developed, and implemented for a large government building. Data logging, combined with an application of artificial neural networks (ANNs), provides short-term electrical load forecasting data for controlled peak demand. The ANN model was tested against other forecasting methods including simple moving average (SMA), linear regression, and multivariate adaptive regression splines (MARSplines) and was effective at forecasting peak building electrical demand in a large government building sixty minutes into the future. The ANN model presented here outperformed the other forecasting methods tested with a mean absolute percentage error (MAPE) of 3.9% as compared to the SMA, linear regression, and MARSplines MAPEs of 7.7%, 17.3%, and 7.0% respectively. Additionally, the ANN model realized an absolute maximum error (AME) of 8.2% as compared to the SMA, linear regression, and MARSplines AMEs of 26.2%, 45.1%, and 22.5% respectively. Full article
(This article belongs to the Special Issue Energy Efficient Building Design and Operation 2014)
Open AccessArticle Evaluation of Visitor Counting Technologies and Their Energy Saving Potential through Demand-Controlled Ventilation
Energies 2014, 7(3), 1685-1705; doi:10.3390/en7031685
Received: 8 February 2014 / Revised: 18 March 2014 / Accepted: 19 March 2014 / Published: 21 March 2014
Cited by 2 | PDF Full-text (964 KB) | HTML Full-text | XML Full-text
Abstract
Direction-sensitive visitor counting sensors can be used in demand-controlled ventilation (DCV). The counting performance of two light beam sensors and three camera sensors, all direction sensitive, was simultaneously evaluated at an indoor location. Direction insensitive sensors (two mat sensors and one light [...] Read more.
Direction-sensitive visitor counting sensors can be used in demand-controlled ventilation (DCV). The counting performance of two light beam sensors and three camera sensors, all direction sensitive, was simultaneously evaluated at an indoor location. Direction insensitive sensors (two mat sensors and one light beam sensor) were additionally tested as a reference. Bidirectional counting data of free people flow was collected for 36 days in one-hour resolution, including five hours of manual counting. Compared to the manual results, one of the light beam sensors had the most equally balanced directional overall counting errors (4.6% and 5.2%). The collected data of this sensor was used to model the air transportation energy consumption of visitor counting sensor-based DCV and constant air volume ventilation (CAV). The results suggest that potential savings in air transportation energy consumption could be gained with the modeled DCV as its total daily airflow during the test period was 54% of the total daily airflow of the modeled CAV on average. A virtually real-time control of ventilation could be realized with minute-level counting resolution. Site-specific calibration of the visitor counting sensors is advisable and they could be complemented with presence detectors to avoid unnecessary ventilation during unoccupied periods of the room. A combination of CO2 and visitor counting sensors could be exploited in DCV to always guarantee sufficient ventilation with a short response time. Full article
(This article belongs to the Special Issue Energy Efficient Building Design and Operation 2014)
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Open AccessArticle Study of the Vertical Distribution of Air Temperature in Warehouses
Energies 2014, 7(3), 1193-1206; doi:10.3390/en7031193
Received: 9 January 2014 / Revised: 6 February 2014 / Accepted: 12 February 2014 / Published: 27 February 2014
Cited by 4 | PDF Full-text (1120 KB) | HTML Full-text | XML Full-text
Abstract
Warehouses are usually large, plain industrial buildings commonly used for storage of goods. Vertical distribution of air temperature is an important aspect for indoor environment design, which must be taken into account by architects and engineers in the early stages of warehouse [...] Read more.
Warehouses are usually large, plain industrial buildings commonly used for storage of goods. Vertical distribution of air temperature is an important aspect for indoor environment design, which must be taken into account by architects and engineers in the early stages of warehouse design. The aim of this work is to analyze the vertical temperature gradients existing in warehouses, quantifying their value and analyzing their evolution along the year. To do so, the study outlines the monitoring of several warehouses with different building typology and height located in different areas of Spain for a complete annual cycle. The results obtained when applying a simple linear regression analysis to 175,200 vertical temperature profiles show that there is a strong influence of the outdoor temperature over the stratification of the indoor air. During warm months, the ceiling and the upper strata get warmer, whereas the cold air accumulates in the lower levels, increasing the stratification of indoor air (maximum values between 0.3 °C/m and 0.7 °C/m). During cold months, the ceiling gets cold due to its contact with the outdoor air, therefore, the colder, heavier air moves down to the lower strata, registering insignificant vertical temperature differences. Air conditioning of the warehouse, besides controlling the temperature, limits the influence of the outdoor environment on the stratification of temperatures. The results of the study may be of great use for warehouses for products sensitive to temperature, which may suffer a different evolution, conservation or maturation when the temperature differences are maintained for a long time. Full article
(This article belongs to the Special Issue Energy Efficient Building Design and Operation 2014)

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