Conference PaperPDF Available


With adaptive building façade technologies, a building envelope can provide a comfortable indoor environment under varying external conditions with minimal additional heating or cooling. The control strategy applied to the adaptation of the façade is a key determining factor in the successful integration of these technologies into a building. The building envelope plays a key role in regulating light, heat and mass transfer from the outdoor environment to the indoor. Dynamic glazing can be used to adjust the amount of solar radiation entering a building. The control strategies that ultimately determine the success of these switchable technologies to affect a building's energy performance and occupant comfort are reviewed in this paper.
Dublin Institute of Technology
Conference papers School of Electrical and Electronic Engineering
A Review of Control Methodologies for Dynamic
Eoin D. McLean
Dublin Institute of Technology,
Brian Norton
Dublin Institute of technology,
Derek Kearney
Dublin Institute of Technology,
Philippe Lemarchand
Dublin Institute of Technology,
Follow this and additional works at: h9ps://
Part of the Engineering Science and Materials Commons
8is Conference Paper is brought to you for free and open access by the
School of Electrical and Electronic Engineering at ARROW@DIT. It has
been accepted for inclusion in Conference papers by an authorized
administrator of ARROW@DIT. For more information, please contact,,
8is work is licensed under a Creative Commons A9ribution-
Noncommercial-Share Alike 3.0 License
Recommended Citation
McLean, E., Norton, B., Kearney, D. & Lemarchand, P. (2017), A review of control methodologies for dynamic glazing. Advance
Building Skins 2017Berne, Switzerland, 2 -3 October.
A Review of Control Methodologies for Dynamic Glazing
Eoin McLean, Brian Norton, Derek Kearney, Phillipe Lemarchand
Dublin Energy Lab, Dublin Institute of Technology, Dublin, Ireland
With adaptive building façade technologies, a building envelope can provide a comfortable indoor
environment under varying external conditions with minimal additional heating or cooling. The control
strategy applied to the adaptation of the façade is a key determining factor in the successful
integration of these technologies into a building. The building envelope plays a key role in regulating
light, heat and mass transfer from the outdoor environment to the indoor. Dynamic glazing can be
used to adjust the amount of solar radiation entering a building. The control strategies that ultimately
determine the success of these switchable technologies to affect a buildings energy performance and
occupant comfort are reviewed in this paper.
Directive 2010/31/EU (EPBD recast) states that from January 2019, all new public buildings in the
European Union (EU) will have to be designed to Nearly Zero Energy Building (NZEB) standards and all
other new buildings will have to comply with NZEB from January 2021. An NZEB is a building that has
a very high energy performance with a very significant amount of its energy requirement met by
renewable sources [1]. The expectations for EU member states in Zone 4 - Oceanic climates”, which
includes Ireland, is as follows:
Offices: 40-55 kWh/(m2.y) of net primary energy with, typically, 85-100 kWh/(m2.y) of primary
energy use covered by 45 kWh/(m2.y) of on-site renewable sources;
New single family house: 15-30 kWh/(m2.y) of net primary energy with, typically, 50-65
kWh/(m2.y) of primary energy use covered by 35 kWh/(m2.y) of on-site renewable sources;
Specific building design requirements will vary according to function, site, climate, façade orientation
and regulatory/code specifications. The choice of glazing has a significant impact on overall building
energy performance [3]. Buildings located in heating-dominated climates will want to maximise solar
gains, thereby reducing artificial heating requirements. Those located in cooling-dominated climates
will want to reduce cooling loads by minimising solar gains. These relatively simplistic requirements
are complicated by the need to consider occupant comfort, changing occupancy, diurnal changes in
weather and heat stored in the building fabric. Introducing glare as a design consideration can
significantly reduce energy efficiency in heating dominated climates [4]. Air quality requirement and
acoustic comfort must be fulfilled when considering the building and the operation of all mechanical
and electrical services in an holistic manner. Some of these considerations are measurable; such as
daylight illuminance and temperature, however the quality of the view of the outside environment is
more difficult to quantify. Optimising windows for visual comfort can lead to high energy
consumption, whereas windows optimised for energy efficiency do not always meet general visual
acceptance criteria [5]. These multiple design requirements make choosing an appropriate control
strategy for window systems that can change their thermal and optical characteristics even more
challenging [4]. Liu et al. [6], found that the use of dynamic glazing enables an increase in Glazing Ratio
(GR), without compromising building performance; even with a GR of 100%, the dynamic glazing
outperformed a static façade with a GR of 20%.
As it is difficult to optimise windows for visual or thermal comfort and at the same time minimise
building energy use [5], a compromise is required when choosing the size, type and location of the
glazing. A significant difficulty in determining the best control strategy is the need for an adaptive
façade to address multiple conflicting performance requirements often across differing physical
domains such as visual comfort, thermal comfort and energy efficiency [4]. A simple example is the
conflict between minimising glare risk while maximising solar gains. Control strategies have attempted
to optimise visual and thermal comfort while simultaneously achieving low energy consumption
targets. [7]. To truly maximise the use of dynamic glazing, controlled external shading may be
required [5], [6],[8]. The need to control such shading adds a further level of complexity to any
potential control strategy.
Types of Control Strategies
Self-triggered passive/dynamic glazings include Thermochromic (TC), Thermotropic (TT) and
Photochromic (PC). Glazings that can be triggered by an external stimulus are categorised as
active/intelligent. They include Electrochromic (EC), Suspended Particle Devices (SPD) and Liquid
Crystal Devices (LCD) [4]. Their characteristics are included in Table 1.
Table 1: Characteristics of Dynamic Glazing
Power Req.
No. of
To Switch
3-7 min
75 VAC
<10 W/m2
2 min
Advanced control strategies can lead to significant improvements in building energy performance
without compromising visual comfort [7],[9]. Current control strategies for glazing’s are either (i) Rule-
Based Control (RBC), (ii) Model-Predictive Control (MPC) also referred to as Receding-Horizon Control
(RHC), or (iii) Genetic Algorithms (GA). The majority of studies have examined a relatively simple rule
based control [4],[9],[10]. These strategies are generally unable to optimise contrasting requirements,
such as the optimisation of solar gain contrasted with the desire to reduce summer cooling loads.
Notwithstanding this, they frequently outperform some of the more complex alternatives [4].
(i) Rule Based Control
A RBC strategy is defined by a set of rules that rely on measurements of the current or past states of
the building (i.e. lighting levels, temperature, building energy demand). It uses an external decision
making system of sensors, control algorithms and actuators [4]. A number of different RBC’s have
been tested for control of dynamic glazing [11]. RBC control strategies use one or more pre-
determined instructions acting on measured or pre-set data values [11]. Dussaullt et al. [9] used two
RBC control strategies in their study, RBC1 and RBC2. Both were designed to maximise daylight
without exceeding 500 lx. If this threshold was exceeded the glazing switched to the next darkest state
that would keep the daylight level below 500 lx. The difference between the two strategies was the
operation of the glazing during the hours when the building was said to be unoccupied. RBC1 switched
to its clearest state, thereby maximising solar gain and RBC2 switched to its darkest state, minimising
cooling requirement. Of the two strategies, RBC2 performed better even outperforming some of the
more complex GA and MPC strategies. It was noted, that the use of energy efficient artificial lighting
systems has a significant impact on the effectiveness of the control strategies. Using onoff switches
where the switch is triggered by the level of indoor illuminance or global solar radiation,
Assimakopoulos et al. [7] achieved similar results within ≈ 2%, with their RBC to those achieved using
a more complex fuzzy logic control. This study however, (i) did not compare results with a standard
glazing (ii) only relates to lighting, heating and cooling energy consumption and (iii) does not present
data on daylighting or glare comfort. In a simulation study, Fernandes et al. [8] used target indoor
illuminance and luminance levels as the design parameters for determining the performance of a split
pane EC window used in conjunction with automatic roller blinds to reduce lighting energy
consumption. Their control strategy used a least-squares algorithm with linear inequality constraints.
This work did not attempt to compare control strategies but rather utilised this particular method of
control to compare the performance of an EC window with a standard reference glazing. They found
that if the blinds are operated once per day at the first instance of visual discomfort, the annual
lighting energy consumption was reduced by 37% 48%. Favoino et al. [4] found that although RBC
strategies could outperform more complex strategies for a single performance requirement, they
were generally unable to optimise multiple performance objectives. Importantly, this study did show
that a RBC strategy could outperform the best static glazing option. A simulation carried out by Tavares
et al. [12], used a simple control strategy based only on incident solar radiation applied to south, east
and west facades in a Mediterranean climate but did not consider the effect of glare on occupant
comfort. They concluded that this type of strategy resulted in energy savings compared to a standard
single or double glazing.
(ii) Model Predictive Control
Model Predictive Control algorithms use a defined and specific system model to predict the future
response of that system over a pre-determined time horizon [13]. The main premise is that there is
useful information contained in the future of that system which can be used to improve the system
control and performance [14]. Though first developed to control power plants and petroleum
refineries, their use is now widespread. At each time step, an MPC algorithm optimizes the sequence
of control values, over the prediction horizon based on the predictions of the model [9]. The control
predictions of the model are then applied to the model in real time. An MPC model has three distinct
parts, the observer, the optimizer and the predictor. Dussault et al. [9], used an MPC control strategy
with the objective of minimising the total energy consumption of the building. While the results of this
strategy were promising, it was still outperformed by the RBC2 and GA strategies. A possible reason
for this was that the simplicity of the building model did not allow the increased intelligence of the
MPC controller to be fully utilised. A study by Favoino et al [4], found that MPC control strategies have
a better energy performance than any of the reactive RBC strategies tested. This is because MPC
strategies are able to minimise total building energy use, while the RBC strategies can only minimise
total building loads. As the results of an MPC control strategy are only as good as the predictions of
the system it is essential to identify the optimal predictors for any given system.
(iii) Genetic Algorithms
GA can be used either to find a single set of input variables that will optimise one or many performance
requirements into a single solution or a set of optimal solutions that recognises the lack of any one
perfect solution [15]. A GA would be recognised as easy to use and robust but can be slow compared
to other optimisation methods. Due to being probabilistic, they can produce different results with the
same inputs [9]. Dussault et al. [9], used a GA with the objective of minimising overall energy
consumption, due to the computational expense and time associated with optimal GA solutions, a
quasioptimal solution was used [9]. It was found that with a traditional T8 fluorescent lighting system,
the GA offered the lowest energy consumption of all control strategies, but with more efficient LED
lighting, the simple RBC controllers performed as well as the GA.
The difference in performance between their best and worst performing strategies has been found to
be less than 10% [7] due to the small dynamic range of the Solar Heat Gain Coefficient (SHGC) (0.36
0.18, bleached and coloured respectively) for many EC windows. The multiple design constraints are
bounded by limits set by the desire for large glazed areas to maximise daylighting and solar gains to
reduce the need for artificial lighting/heating systems or smaller glazed areas to reduce cooling
demand caused by solar gains which increases the need for artificial lighting [5]. Occupant comfort
must be considered as part of any design or control strategy. Visual comfort plays such an important
role in overall occupant comfort, that it requires very thorough consideration[16]. In cooling-
dominated climates, the energy consumption of a building is very sensitive to the chosen control
strategy and reactive control has been shown to be as effective as predictive control for dynamic
glazing, whereas in heating-dominated climates, predictive control has yielded better results [4].
Simple control strategies work well on simple building models. Many authors have noted that the lack
of modelling complexity has reduced the performance benefits of intelligent control strategies such
as MPC and particularly GA. RBC strategies offer a simple means of control, that may yield building
energy savings but it is generally accepted that they are unable to meet more than a single
performance objective. There is enough research to suggest that current dynamic glazing alone may
not provide sufficient flexibility to produce the desired combination of energy savings and visual
comfort. A possible solution to this is presented in [17] through the use of a hybrid window using an
infrared Chiral Liquid Crystal (CLC) mirror and SPD window to independently control solar radiant heat
transmission, visible transmission and glare through the window. Studies combining the use of shading
with dynamic glazing have suggested that when considering the application of smart facades, it may
be necessary to consider the entire façade and not simply a single part.
Research conducted to date has used building simulations and virtual modelling environments. While
these studies can clearly demonstrate the ways in which dynamic glazing may be controlled, it is
necessary to conduct physical field trials and record the results of dynamic glazing being controlled in
a variety of climates and with a variety of control methodologies.
[1] F. Madonna and F. Ravasio, “Definition of nearly zero energy building and cost-optimal energy
performance in 2020.”
[2] “COMMISSION RECOMMENDATION (EU) 2016/ 1318 - of 29 July 2016 - on guidelines
for the promotion of nearly zero-energy buildings and best practices to ensure that, by
2020, all new buildings are nearly zero-energy buildings,” Comm. Recomm., 2016.
[3] Julijana Velevskaa, M. P. Gjorgjevichb, and Nace Stojanovc, “Electrochromic Nickel Oxide Thin
Films for Solar Light Modulation,” Int. J. Sci. Basic Appl. Res., vol. 31, no. 3, pp. 94104, 2017.
[4] F. Favoino, F. Fiorito, A. Cannavale, G. Ranzi, and M. Overend, “Optimal control and
performance of photovoltachromic switchable glazing for building integration in temperate
climates,” Appl. Energy, 2016.
[5] C. E. Ochoa, M. B. C. Aries, E. J. van Loenen, and J. L. M. Hensen, “Considerations on design
optimization criteria for windows providing low energy consumption and high visual comfort,”
Appl. Energy, vol. 95, pp. 238245, 2012.
[6] M. Liu, K. B. Wittchen, and P. K. Heiselberg, “Control strategies for intelligent glazed façade and
their influence on energy and comfort performance of office buildings in Denmark,” Appl.
Energy, vol. 145, pp. 4351, 2015.
[7] M. N. Assimakopoulos, A. Tsangrassoulis, M. Santamouris, and G. Guarracino, “Comparing the
energy performance of an electrochromic window under various control strategies,” Build.
Environ., vol. 42, no. 8, pp. 28292834, 2007.
[8] L. L. Fernandes, E. S. Lee, and G. Ward, “Lighting energy savings potential of split-pane
electrochromic windows controlled for daylighting with visual comfort,” Energy Build., vol. 61,
pp. 820, 2013.
[9] J. M. Dussault, M. Sourbron, and L. Gosselin, “Reduced energy consumption and enhanced
comfort with smart windows: Comparison between quasi-optimal, predictive and rule-based
control strategies,” Energy Build., vol. 127, pp. 680691, 2016.
[10] F. Gugliermetti and F. Bisegna, “Visual and energy management of electrochromic windows in
Mediterranean climate,” Build. Environ., vol. 38, no. 3, pp. 479492, Mar. 2003.
[11] E. S. Lee et al., “Advancement of Electrochromic Windows,” Lawrence Berkeley Natl. Lab.,
[12] P. Tavares, H. Bernardo, A. Gaspar, and A. Martins, “Control criteria of electrochromic glasses
for energy savings in mediterranean buildings refurbishment,” Sol. Energy, vol. 134, 2016.
[13] S. J. Qin and T. A. Badgwell, “A survey of industrial model predictive control technology,”
Control Eng. Pract., vol. 11, no. 7, pp. 733764, 2003.
[14] H. B. Gunay, J. Bursill, B. Huchuk, W. O’Brien, and I. Beausoleil-Morrison, “Shortest-prediction-
horizon model-based predictive control for individual offices,” Build. Environ., vol. 82, pp. 408
419, 2014.
[15] L. Gosselin, M. Tye-Gingras, and F. Mathieu-Potvin, “Review of utilization of genetic algorithms
in heat transfer problems,” Int. J. Heat Mass Transf., vol. 52, no. 9, pp. 21692188, 2009.
[16] Y. Al horr, M. Arif, M. Katafygiotou, A. Mazroei, A. Kaushik, and E. Elsarrag, “Impact of indoor
environmental quality on occupant well-being and comfort: A review of the literature,” Int. J.
Sustain. Built Environ., vol. 5, no. 1, pp. 111, 2016.
[17] P. Lemarchand, J. Doran, and B. Norton, “Smart Switchable Technologies for Glazing and
Photovoltaic Applications,” Energy Procedia, vol. 57, pp. 18781887, 2014.
... After initialization, facade control laws compete to see how effective each law is and rate them accordingly. Thus highly-rated control laws breed more effective next-generation control laws using genetic operations [114,115]. ...
Full-text available
A major objective in the design and operation of buildings is to maintain occupant comfort without incurring significant energy use. Particularly in narrower-plan buildings, the thermophysical properties and behaviour of their façades are often an important determinant of internal conditions. Building facades have been, and are being, developed to adapt their heat and mass transfer characteristics to changes in weather conditions, number of occupants and occupant’s requirements and preferences. Both the wall and window elements of a facade can be engineered to (i) harness solar energy for photovoltaic electricity generation, heating, inducing ventilation and daylighting (ii) provide varying levels of thermal insulation and (iii) store energy. As an adaptive façade may need to provide each attribute to differing extents at particular times, achieving their optimal performance requires effective control. This paper reviews key aspects of current and emerging adaptive façade technologies. These include (i) mechanisms and technologies used to regulate heat and mass transfer flows, daylight, electricity and heat generation (ii) effectiveness and responsiveness of adaptive façades, (iii) appropriate control algorithms for adaptive facades and (iv) sensor information required for façade adaptations to maintain desired occupants’ comfort levels while minimising the energy use.
... Research conducted to date has adopted building simulations and virtual modelling environments. While these studies can clearly demonstrate the ways in which dynamic glazing may be controlled, it is necessary to conduct physical field trials and record the results of dynamic glazing being controlled in a variety of climates and with a variety of control methodologies [16]. ...
Full-text available
The ever-increasing aesthetically driven demand for fully glazed façades poses a design challenge; not least in controlling the cooling demand and occupant well-being of such buildings, especially in a central Mediterranean climate. This paper outlines the ever-important need to design for occupants and for designers to keep in mind, first and foremost, occupant well-being rather than aim solely to create energy-efficient buildings. The original objective of buildings was to provide shelter. Today however, the need for occupant comfort and its direct effect on productivity cannot be ignored. This need, therefore, ought to feature a central role in any building design. Studies show that occupant well-being is directly related to a range of environmental factors, particularly daylight distribution, glare and indoor air temperature. The use of external shading devices and more commonly, indoor blinds are often the adopted approaches to attempt to achieve indoor occupant comfort, often to the detriment of views. Adaptive facades seek to address the need to somehow strike a balance between occupant comfort and energy efficiency. These facades range from exterior and interior shading devices with varying control strategies, to the different forms of adaptive/switchable glazing technologies intended to control the visual light transmittance and solar radiation transmitted into a building’s interior. In the opinion of the authors, electrochromic glazing has a great potential in a cooling-dominated central Mediterranean climate, to achieve a compromise between occupant visual and thermal comfort whilst retaining unobstructed outdoor views at all times. Research shows that the potential benefits of electrochromic glazing have not yet been studied enough in real-life scenarios,and this paper further introduces the objectives for field study within two identical offices, having a South-South-East orientation, located in a central Mediterranean climate.
Full-text available
Nickel oxide (NiO x) thin films were prepared by three different deposition techniques: electrochemical (EC) deposition, low vacuum evaporation (LVE), and chemical bath deposition (CBD). Those films were deposited onto fluorine doped tin oxide (FTO) coated glass substrates. Electrochromic behavior of the films was examined in an electrochromic device (ECD) constructed by using NiO x films as working electrodes, together with the FTO coated glass as a counter electrode in alkaline environment (0.1 M NaOH aqueous solution). The films exhibited anodic electrochromism, changing color from transparent to dark brown. Visible transmittance spectra of the nickel oxide thin films in bleached and colored states were recorded in-situ. Absorption coefficients spectra were calculated using the transmittance spectra. The output integral of the spectral intensity and the integral of the spectral modulation were calculated by taking the solar irradiance spectrum AM 1.5 for a normal illumination on a nickel oxide – based ECD, and the absorption coefficients spectra of the nickel oxide films in their bleached and colored states.
Full-text available
The development of adaptive building envelope technologies, and particularly of switchable glazing, can make significant contributions to decarbonisation targets. It is therefore essential to quantify their effect on building energy use and indoor environmental quality when integrated into buildings. The evaluation of their performance presents new challenges when compared to conventional “static” building envelope systems, as they require design and control aspects to be evaluated together, which are also mutually interrelated across thermal and visual physical domains. This paper addresses these challenges by presenting a novel simulation framework for the performance evaluation of responsive building envelope technologies and, particularly, of switchable glazing. This is achieved by integrating a building energy simulation tool and a lighting simulation one, in a control optimisation framework to simulate advanced control of adaptive building envelopes. The performance of a photovoltachromic glazing is evaluated according to building energy use, Useful Daylight Illuminance, glare risk and load profile matching indicators for a sun oriented office building in different temperate climates. The original architecture of photovoltachromic cell provides an automatic control of its transparency as a function of incoming solar irradiance. However, to fully explore the building integration potential of photovoltachromic technology, different control strategies are evaluated, from passive and simple rule based controls, to optimised rule based and predictive controls. The results show that the control strategy has a significant impact on the performance of the photovoltachromic switchable glazing, and of switchable glazing technologies in general. More specifically, simpler control strategies are generally unable to optimise contrasting requirements, while more advanced ones can increase energy saving potential without compromising visual comfort. In cooling dominated scenarios reactive control can be as effective as predictive for a switchable glazing, differently than heating dominated scenarios where predictive control strategies yield higher energy saving potential. Introducing glare as a control parameter can significantly decrease the energy efficiency of some control strategies, especially in heating dominated climates.
Full-text available
Apparent window size contradictions arise when optimizing simultaneously for low energy (small sizes) and visual comfort (large sizes). Diverse multi-objective optimization methods exist, but basic questions must be solved beforehand such as choosing appropriate evaluation measures. This work aims to determine the suitability of combined optimization criteria on window sizing procedures for low energy consumption with high visual comfort and performance. The paper showcases diverse measures available to valorise energy consumption and visual aspects. A series of energy and visual criteria were selected, defining acceptance thresholds for dynamic evaluations. Whole-building computer simulations were performed on a standardized office located in a temperate climate. Discrete window-to-wall ratio variations were studied to demonstrate how these criteria affect the solution space. Results were classified using a graphical optimization method, obtaining a solution space satisfying both energy and visual requirements. Most project expectations can be met within the range of sizes. However, unprotected windows barely meet acceptance criteria, needing additional control devices. Applying various related criteria with adequate values increases the diversity of acceptable solutions but too many limits it. Clear objectives and acceptance ranges have to be conceptualized in order to translate them into decisions. This becomes important when involving team design.
Smart windows are used to reduce energy consumption and improve thermal and visual comfort mainly by controlling the solar flux entering into a building. This article presents a simulation study in which the impact of the applied control strategy on the overall energy consumption (heating, cooling and lighting) is investigated. A commercial building located in Montreal (Canada) with south-oriented integrated electrochromic windows is modeled. The hour-by-hour state of the smart windows required to minimize overall energy consumption while respecting constraints related to thermal and visual comfort is determined through an optimization strategy based on genetic algorithms (GA). Then, this quasi-optimal control is compared to other approaches that could be applied in real-time applications: (i) two types of rule-based controls (RBC), i.e. RBC1 and RBC2 and (ii) a model predictive control (MPC). The impacts of thermal mass and installed light power density are also analyzed. Results show that the four control strategies under study presented similar energy consumption with differences in total energy consumption ranging from 4% to 10%. While more complex controllers such as MPC could potentially lead to improved performances considering more design variables, complex models and extensive commissioning, this study illustrates that simpler control strategies such as RBC2 can also lead to satisfying results.
During the next decades the refurbishment of old buildings will be an essential way to contribute to the global improvement of buildings energy performance indicators. Within this context, the present paper is focused on the use of electrochromic (EC) windows, an emerging technology alternative to shading devices, to control solar gains in buildings located in Mediterranean climates. The optical properties adjustments of the EC glasses are discussed based on the incident solar radiation. The ESP-r building energy simulation software was used to study the energy savings resulting from the application of electrochromic windows, considering the comparison of several windows solutions (single, double-glazing and EC windows) and windows orientations (East, South and West). In addition, different transition ranges for the optical properties of the EC glasses are assessed through the analysis of the energy needs for space heating and cooling. The main conclusion is that EC technology is an effective option in cooling dominated buildings. The impact of EC windows is highly dependent on facade orientation, being a valid option particularly in the cases of the East and West facades. For these facades, the control set point found to be effective corresponds to an incident solar radiation on the glass of 150 W/m2 to impose a total coloured state. For the South facade the results show no significant advantage of using EC windows.
Indoor Environmental Quality (IEQ) and its effect on occupant well-being and comfort is an important area of study. This paper presents a state of the art study through extensive review of the literature, by establishing links between IEQs and occupant well-being and comfort. A range of issues such as sick building syndrome, indoor air quality thermal comfort, visual comfort and acoustic comfort are considered in this paper. The complexity of the relationship between occupant comfort and well-being parameters with IEQ are further exacerbated due to relationships that these parameters have with each other as well. Based on the review of literature in these areas it is established that design of buildings needs to consider occupant well-being parameters right at the beginning. Some good practices in all these different areas have also been highlighted and documented in this paper. The knowledge established as part of this paper would be helpful for researchers, designer, engineers and facilities maintenance engineers. This paper will also be of great benefit to researchers who endeavour to undertake research in this area and could act as a good starting point for them.
A simulation study was conducted to evaluate lighting energy savings of split-pane electrochromic (EC) windows controlled to satisfy key visual comfort parameters. Using the Radiance lighting simulation software, interior illuminance and luminance levels were computed for a south-facing private office illuminated by a window split into two independently-controlled EC panes. The transmittance of these was optimized hourly for a work plane illuminance target while meeting visual comfort constraints, using a least-squares algorithm with linear inequality constraints. Blinds were successively deployed until visual comfort criteria were satisfied. The energy performance of electrochromics proved to be highly dependent on how blinds were controlled. With hourly blind position adjustments, electrochromics showed significantly higher (62% and 53%, respectively without and with overhang) lighting energy consumption than clear glass. With a control algorithm designed to better approximate realistic manual control by an occupant, electrochromics achieved significant savings (48% and 37%, respectively without and with overhang). In all cases, energy consumption decreased when the workplace illuminance target was increased. In addition, the fraction of time during which the occupant had an unobstructed view of the outside was significantly greater with electrochromics: 10 months out of the year vs. a handful of days for the reference case.
This review presents when and how Genetic Algorithms (GAs) have been used over the last 15 years in the field of heat transfer. GAs are an optimization tool based on Darwinian evolution. They have been developed in the 1970s, but their utilization in heat transfer problems is more recent. In particular, the last couple of years have seen a sharp increase of interest in GAs for heat transfer related optimization problems. Three main families of heat transfer problems using GAs have been identified: (i) thermal systems design problems, (ii) inverse heat transfer problems, and (iii) development of heat transfer correlations. We present here the main features of the problems addressed with GAs including the modeling, number of variables, and GA settings. This information is useful for future use of GAs in heat transfer. Future possibilities and accomplishments of GAs in heat transfer are also drawn.