Analysis of the influence of different variables on the impacts related with the envelope of buildings for residential use, with estimation of the interaction of the user
Patricia Huedo a, Belinda López-Mesab and Elena Muleta
aDepartamento de Ingeniería Mecánica y Construcción, Universitat Jaume I, Castellón de la Plana, Spain; bDepartmento de Arquitectura, Universidad de Zaragoza, Zaragoza, Spain
ABSTRACT
There is an important mismatch, or gap, between the predicted and actual measurements of the impacts that are produced, mainly
during the use phase of buildings. In this study, the authors estimated the weight of the different explanatory variables used to define the model for predicting the impacts in the evaluation of the dependent variables considered: ‘CO2 equivalent emissions’
and ‘primary energy consumption’. The study explores the extent to which the intervention of high- or low-energy users (depending on their purchasing power) influences the impacts of the use phase linked to the envelope, ‘user interaction’ being considered as a variable that modifies the impact predicted by the model. The results obtained show that, without taking the user into account, climate zone is the variable with the greatest influence, since it accounts for over 80% of the variation in heating
consumption in the use phase. However, on analysing the influence of the user in zones with a continental climate, the results varied with respect to the predicted value, from 5% in the case of low-energy users up to more than 53% when they are very high-energy users.
KEYWORD S
Construction; GAP; user interaction; weight of explanatory variables; impacts estimation
Co-simulation of fuzzy control in buildings and the HVAC system using BCVTB
Christina Anastasiadi and Anastasios I. Dounis
Department of Automation Engineering, Piraeus University of Applied Sciences (T.E.I. of Piraeus), Athens, Greece
ABSTRACT
The present study investigates the use of fuzzy logic in Heating Ventilation and Air Conditioning (HVAC) control as means of
enhancing thermal comfort provision for the building occupants while maintaining or improving the resulting energy consumption of the building’s HVAC system. In order to assess the application of fuzzy logic on HVAC control, a single zone building model along with an HVAC model are created using EnergyPlus software and Transient System Simulation Tool, respectively. In addition a HVAC fuzzy logic controller along with a conventional on-off controller, both thermal comfort based, were developed using Simulink. The latter simulation models, implemented via different software, were coupled using the Building Control Virtual Test Bed platform as a middleware. The simulation outcomes of the on-off controller were used as a benchmark for the evaluation of the fuzzy HVAC controller. In terms of the provided thermal comfort to the building occupants the fuzzy HVAC controller appeared superior, as it managed to reduce the annual mean percentage of dissatisfied occupants by 33% as well as the non-comfort hours by more than 50%. In terms of energy consumption the simulation results suggested that the two controllers perform almost on par.
KEYWORD S
Fuzzy control; thermal comfort; simulation; BCVTB; HVAC
Corridor lighting retrofit based on occupancy and daylight sensors: implementation and energy savings compared to LED lighting
Stavros Akrasakisa and Antonios G. Tsikalakis a,b
aSchool of Electrical Engineering, Technical Educational Institute (TEI) of Crete, Heraklion, Greece; bHellenic Electricity Distribution Network Operator, HEDNO, Energy Dispatch Center of Crete, Heraklion, Greece
ABSTRACT
Educational buildings have significant energy savings potential if they benefit from daylight. Secondary spaces such as corridors
when controlled by combination of daylight and occupancy sensors seem to present significant savings as well. In this paper, the retrofitting of the lighting installation in a corridor in an educational building is presented based on Arduino controller and daylight and occupancy sensors without changing the T8 lamps. The energy savings are calculated based on measurements
reaching 85% for a working day and they are higher compared to the case of retrofitting the lighting only by changing the fluorescent lamps with LED ones at the same cost.
KEYWORD S
Lighting control; daylight; energy savings; educational buildings; Arduino
Experimental investigation of free cooling using phase change material-filled air heat exchanger for energy efficiency in buildings
Thambidurai Muthuvelana, Karthik Panchabikesanb, Rajagopal Munisamyc, Krishna Mohan Nibhanupudia and Velraj Ramalingamb
aDepartment of Mechanical Engineering, Annamalai University, Chidambaram, India; bInstitute for Energy Studies, Anna University, Chennai, India; cDepartment of Mechanical Engineering, Priyadarshini Engineering College, Vaniyambadi, India
ABSTRACT
In the present work, the ability for storing useful energy available in the night time ambient air in a flat modular type phase change material (PCM)-based storage type heat exchanger and retrieving the same for daytime cooling requirements was experimentally investigated. A cabin with an area of 64 ft2 was constructed and free cooling feasibility for the built cabin was investigated using the ambient conditions that prevail in Pune city, India. Considering the climatic conditions of Pune city, HS 29
(commercial PCM) was chosen as the PCM. Several charging/discharging experiments were conducted in order to analyse the
solidification/melting characteristics of the chosen PCM. The temperature variation, instantaneous and cumulative heat transfer
during both the charging and discharging experiments were evaluated and reported. From the results obtained it is inferred
that an average reduction of 2.5°C in the room temperature was achieved in the present investigation. Also, it is understood that
free cooling potential can further be increased by reducing the losses and the requirement of mechanical air conditioners may totally be eliminated if free cooling technology is integrated with the other passive cooling concepts such as evaporative cooling
and nocturnal radiative cooling systems.
KEYWORD S
Latent heat thermal energy storage; phase change materials; free cooling; green buildings; modular heat exchanger
Improving office building energy-efficiency ratings using a smart-engineering– computer-simulation approach: an Australian case study
Steve Burroughsa,b
aPrincipal Consultant, Sustainable Building Consultant/Academic Advisor, Dr Steve Burroughs, Macquarie, Australia; bAdjunct Associate Professor (Architecture), University of Canberra, Canberra, Australia
ABSTRACT
Building owners in Australia are increasingly being required to proactively manage the environmental aspects of building
operation. This paper presents a case study of how an Australian property investment trust is improving the energy efficiency of its buildings, and places the case study in the context of the commercial realities of the sustainable property industry. The trust
uses a smart-engineering–computer-simulation approach that involves (i) a comprehensive check of a building’s mechanical–
electrical systems, including examining the building systems brief documentation and the history of maintenance, and (ii) computer simulations of building energy use. The improvements are rated by the National Australian Built Environment Rating System (NABERS), a performance-based rating tool that rates a building’s actual energy consumption from 1.0 to 6.0 stars. In the presented example, an office building in central Sydney has improved its NABERS energy rating from 3.6 stars (2010–2011) to 5.3 stars (2012–2013), representing a 48% reduction in energy use (saving $530,000 pa). Much of the improvement in this building has been achieved by replacing the building management and control system and upgrading the control strategies for the heating, ventilation, and air conditioning system, as shown by the temporal correspondence of the upgrades with submetered
monthly electricity consumption. The engineering–computing approach avoids the need for costly, full-scale refurbishments and
can be applied to other countries with different building sectors and rating tools and with contrasting climates and financial resources to those found in Australia.
KEYWORD S
Office building; energy efficiency; rating tool; sustainable property industry; Australia; smart engineering
Indoor contaminant source identification by inverse zonal method: Levenberg– Marquardt and conjugate gradient methods
Aziz Azimi and Ehsan Daneshgar
Department of Mechanical Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran
ABSTRACT
Indoor contaminant characteristics have been identified traditionally by inverse computational fluid dynamics methods.
However, these methods are too time-consuming and costly. In this study, an inverse zonal method was developed as a simple
model to provide an alternative and inexpensive approach for identifying indoor contaminant source characteristics. In the direct
problem, experimental data and computational fluid dynamics results were employed to validate the reliability of the direct zonal
method. This comparison showed the capability of the directzonal method to simulate the contaminant airflow distribution in
indoor environments. Finally, the inverse zonal method was used to predict the location and strength of an unknown indoor
contaminant source with prior knowledge of the source release time. The inverse techniques for solving the identification
problem were the Levenberg − Marquardt and conjugate gradient methods. The results showed that these inverse methods could
identify the characteristics of a gaseous emission source. Abbreviations: CFD: computational fluid dynamics; ICFD: inverse
computational fluid dynamics; IZM: inverse zonal model; POMA: pressurized zonal model with the air diffuser; QR: quasi-reversibility
KEYWORD S
Zonal method; contaminant distribution; inverse analysis; Levenberg– Marquardt method; conjugates gradient method
Numerical research on the operation characteristics of marine variable air volume air conditioning system
Zhongchao Zhao, Jiaojiao Zhang, Hua Cheng and Rendong Shen
School of Energy and Power Engineering, Jiangsu University of Science and Technology, Zhenjiang, People’ s Republic of China
ABSTRACT
The aim of this study was to explore the operation characteristics of marine variable air volume (VAV) air conditioning system during navigation in each representative day and the whole voyage. In the multifunctional cabins of an ocean-going ship, numerical simulation was carried out to investigate diversified performance parameters of this system. At the same time, the mathematical models of main equipment and VAV system simulation model, which were coupled with an hourly dynamic load calculation model, were developed to analyse the energy consumption in a representative day and the whole voyage. The relative deviations of supply air volumes of all VAV terminals were within 11%, and the supply air temperature and room temperature fluctuated within ±0.2 K and ±0.3 K, respectively. Besides, the energy consumption of this system was lower than that of constant air volume air conditioning system, with the energy-saving rate of 26.82% by simulating calculation.
KEYWORD S
Ship; VAV air conditioning system; operation characteristics
Performance improvement of turbo ventilators with internal
blades
P. M. Ghanegaonkara, Ganesh K. Jadhavb and Sharad Gargc
aMechanical Engineering Department, Dr. D.Y. Patil Institute of Engineering and Technology, Pune, India; b Mechanical Engineering Department, Sinhgad College of Engineering, Pune, India; cContinuum Technology, Pune, India
ABSTRACT
In recent years, natural ventilation has gained prominence for providing ventilation in buildings. The absence of ventilation can
be the source of redundant humidity and pollutants. The turbo ventilator is a mechanical device which is simple in operation and
used extensively for this purpose. In the present study, the existing turbine ventilators (600 mm throat diameter) are tested
experimentally in a specially designed test rig for different wind velocities. The results for 1, 2, 3.5, 5, 7.5 and 9.5 m/s wind velocities are validated with computational fluid dynamics (CFD) analysis. It is observed that the CFD mass flow rate results are within 12–15% more than the experimental results. However, both the analyses have shown a trend of increase in the mass flow rate with an increase in wind velocity. This ventilator is subsequently modified by providing internal blades on the central shaft and tested experimentally. The simulation study has been conducted using CFD to visualize the flow patterns inside and around the turbo ventilators with internal blades. The experimental results show 22% increase in the mass flow rate for the modified turbo ventilator in the wind velocity range of 3.5–7.5 m/s. This paper presents in detail the design and analysis of the modified turbo ventilator.
KEYWORD S
Modified Turbo Ventilator; experimental set-up; testing; CFD simulation
Thermal performance and structural cooling analysis of brick, cement block, and mud concrete block
Chameera Udawattha and Rangika Halwatura
Department of Civil Engineering, Faculty of Engineering, University of Moratuwa, Moratuwa, Sri Lanka
ABSTRACT
This investigation is apropos the thermal analysis and structural cooling of brick, cement block and mud concrete block walling
materials to compare the thermal comfort of different walling materials. Structural cooling is a method of cooling hot temperature by using the structure. Void spaces in a building block can be studied as porosity. It can be measured by assessing solid to void spaces. The thermal performance can be measured by calculating the time lag and the decrement factor. The initial testing was done in order to understand the thermal conductivity and heat capacity in both wet and dry conditions. The real-world analysis and simulation analysis were used to validate the argument. For the case studies, real-world buildings with an identical plan form but constructed with three different walling materials were used and their thermal performances were measured. And then one building was simulated in order to create an identical scenario. With the real-world observation, it was found that brick walling materials have better time lag and decrement factor with the thickness of 225 mm. An overall analysis shows that mud concrete block has better structural cooling ability and the thermal performance than other wall materials.
KEYWORD S
Walling materials; thermal performance; structural cooling; thermal conductivity; time lag and decrement
