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Papers by John Mardaljevic

Journal of Building …, 2009

The Journal of Building Performance Simulation publishes high-quality peer-reviewed articles only... more The Journal of Building Performance Simulation publishes high-quality peer-reviewed articles only through the efforts of our volunteers. Although individual reviews are performed confidentially (each paper is double-blind reviewed by three reviewers), we would like to ...

Journal of Building …, 2009

The Journal of Building Performance Simulation publishes high-quality peer-reviewed articles only... more The Journal of Building Performance Simulation publishes high-quality peer-reviewed articles only through the efforts of our volunteers. Although individual reviews are performed confidentially (each paper is double-blind reviewed by three reviewers), we would like to ...

Building Services Engineering Research and Technology

A new set of CIBSE weather files for building performance simulation was recently developed to ad... more A new set of CIBSE weather files for building performance simulation was recently developed to address the need for better quality solar data. These are essential for most building performance simulation applications, particularly for daylighting studies and low-energy building design, which requires detailed irradiation data for passive solar design and overheating risk analysis. The reliability of weather data becomes paramount when building performance is pushed to its limits. Findings illustrate how principles of good window design can be applied to a case study building, built to the Passivhaus standard, and how its expected performance is affected by the quality of solar irradiation data. Analyses using test reference years were most affected by changes in the solar radiation model (up to 8.3% points), whereas for design summer years the maximum difference was 1.7% points. Adopting the new model caused overheating risk to be classified as more severe using test reference years...

Lighting Research & Technology

Energy and Buildings, Aug 1, 2004

The evaluation of shading devices is generally carried out using a sequence of shadow-pattern ima... more The evaluation of shading devices is generally carried out using a sequence of shadow-pattern images showing the progression of solar penetration for particular times of the day or year. This approach can reveal when solar penetration may occur, say at the summer solstice, but it cannot give a quantitative measure of the degree and likelihood of solar penetration over a representative period of a full year. This paper describes a new image-based technique to quantify the effectiveness of shading devices. It is founded on predictions of direct solar irradiation using hourly meteorological data for a full year. In addition to numerical output, the technique produces synoptic images that reveal the spatial and temporal variation of solar irradiation. There are no practical limits on the scene geometry and buildings with thousands of individual shading elements can be evaluated. The technique is designed to be both fast and highly scalable making it suitable for the evaluation of a large number of design variants. This is demonstrated in the paper using a parametrically defined model of a complex roof shading system based on the Changi Airport Terminal 3 design. The 3600 fins that comprise the roof shading system were generated using a parametric scheme where the fin orientation has a random component. A total of 42 design variants of the roof shading system were evaluated using the new technique.

Astrophysical Letters Communications, 1988

De Montfort University Leicester Uk, 2000

JavaScript is disabled for your browser. Some features of this site may not work without it. ... ... more JavaScript is disabled for your browser. Some features of this site may not work without it. ... Your query "process variability" produced 1037 result(s). ... Daylight simulation : validation, sky models and daylight coefficients. ... This working paper looks at the development of women's professional employment in Europe before the active support of UEFA in the 1970s when two professional leagues operated in Italy to the present situation when Germany ... ... The emerging role of epigenetics in the aetiology of endometriosis. ... BACKGROUND. Endometriosis ...

Energies, 2016

This paper describes the reduced capacity of the inrush current suppressor using a matrix convert... more This paper describes the reduced capacity of the inrush current suppressor using a matrix converter (MC) in a large-capacity wind power generation system (WPGS) with two squirrel-cage induction machines (SCIMs). These SCIMs are switched over depending on the wind speed. The input side of the MC is connected to the source in parallel. The output side of the MC is connected in series with the SCIM through matching transformers. The modulation method of the MC used is direct duty ratio pulse width modulation. The reference output voltage of the MC is decided by multiplying the SCIM current with the variable control gain. Therefore, the MC performs as resistors for the inrush current. Digital computer simulation is implemented to confirm the validity and practicability of the proposed inrush current suppressor using PSCAD/EMTDC (power system computer-aided design/electromagnetic transients including DC). Furthermore, the equivalent resistance of the MC is decided by the relationship between the equivalent resistance and the capacity of the MC. Simulation results demonstrate that the proposed inrush current suppressor can suppress the inrush current perfectly.

With the current development towards increased daylighting in buildings and the related progress ... more With the current development towards increased daylighting in buildings and the related progress in daylight evaluation methods, real life monitoring data becomes an urgent need to better support our understanding of the link between daylight and visual comfort. A data collection methodology is presented that links the physical measurements, using luminance maps derived from High Dynamics Range images, with the collection of user perception data at office workstations. The methodology has been developed to facilitate long-term monitoring of visual comfort in real world working environments. The measurement setup represents a compromise, i.e. the measurement position is not as ideal as that in a laboratory environment, but nevertheless provides useful data for situations where the laboratory approach is not viable. It thus opens a wider range of environments for visual comfort studies.

13Th International Radiance Workshop 2014, Jul 29, 2014

Energy and Buildings, 2003

This paper describes a novel approach for evaluating the total annual/monthly irradiation inciden... more This paper describes a novel approach for evaluating the total annual/monthly irradiation incident on building facades in urban settings. The analysis is founded on a physically-based rendering approach and uses data-visualisation techniques to generate 'maps' (i.e. false-colour images) of annual/monthly irradiation. The irradiation 'maps' are derived from hourly time-series data for 1 year and take accurate account of shading by, and inter-reflection from, other buildings and surfaces. The sun and sky irradiation images are evaluated separately. The sky contribution is calculated using realistic, non-isotropic models for the sky radiance distribution. The 'maps' can be used to confidently identify facade-locations where there is high irradiation, for example to aid the siting of photovoltaic (PV) panels. The technique can be applied to scenes of arbitrary complexity from a single building to fully 'worked-up' city models. The results of the analysis have been linked to a geographical information system (GIS)-based solar energy planning system. The system is targeted at city planners and one of its aims is to encourage the consideration of solar energy in the urban planning process.

13Th International Radiance Workshop 2014, Aug 24, 2014

Book of Abstracts from the 6th International Urban Design, 2013

Mortimer/Electrochromic Materials and Devices, 2013

The energy demands of food retail buildings account for approximately 3% of the UK’s energy consu... more The energy demands of food retail buildings account for approximately 3% of the UK’s energy consumption and resultant carbon emissions. Previous studies demonstrate that the greatest component of the electricity demand of food retail buildings is the cooling demand of the food refrigeration systems (ranging from 30 to 50%). Therefore a better understanding of the electricity demand for refrigeration would enable the development of effective energy management tools, including the evaluation of service and maintenance interventions to reduce operational electricity demand. Various methodologies have been developed and employed in the past for the quick identification of faults during the operation of commercial refrigeration systems. The focus of these methodologies has traditionally been on the temperature of food on the shop floor. The aim of this work is to enhance the existing fault-finding methodologies employed by a global multichannel retail organization, by enabling the identi...

Journal of Sea Research, 1997

The population dynamics of a marine zooplankton species in the Fair Isle Current off northern Sco... more The population dynamics of a marine zooplankton species in the Fair Isle Current off northern Scotland have been investigated by modelling and field study. An age-and weight-structured model of a population of the copepods Culanus jinmarchicus and Calanus helgolandicus was embedded in a biomass based ecosystem model comprising nutrients, phytoplankton, and other non-Calanus zooplankton. The mode1 was configured to represent a Lagrangian water column drifting in the Fair Isle Current off the north of Scotland during June 1988, with physical characteristics derived from the results of a three-dimensional hydrodynamic model of the northwest European shelf. The time-series results from the model were compared to data from a semi-synoptic field study by assuming the system to be short-term steady state and transposing the spatially resolved field observations into pseudo-time series along the modelled column drift track. The hydrodynamic model correctly reproduced the general physical characteristics of the system which were destratification of an initially stratified water column as a result of advection through a tidally energetic mixing zone, and subsequent re-establishment of stratification with distance downstream. The biological components of the model were broadly successful at reproducing the main features of the phytoplankton biomass response to the physical processes. The field data indicated that, despite the short-term changes in phytoplankton abundance along the drift track, the stage composition and biomass of the Calanus population was relatively stable. However, the model revealed that the main diagnostic features of the response were at the individual level, reflected in the weight at age distribution and reproductive output. The study highlights the difficulty of obtaining adequate data for testing complex models of zooplankton responses to short-term spatio-temporal variations in physical forcing.

Journal of Building …, 2009

The Journal of Building Performance Simulation publishes high-quality peer-reviewed articles only... more The Journal of Building Performance Simulation publishes high-quality peer-reviewed articles only through the efforts of our volunteers. Although individual reviews are performed confidentially (each paper is double-blind reviewed by three reviewers), we would like to ...

Journal of Building …, 2009

The Journal of Building Performance Simulation publishes high-quality peer-reviewed articles only... more The Journal of Building Performance Simulation publishes high-quality peer-reviewed articles only through the efforts of our volunteers. Although individual reviews are performed confidentially (each paper is double-blind reviewed by three reviewers), we would like to ...

Building Services Engineering Research and Technology

A new set of CIBSE weather files for building performance simulation was recently developed to ad... more A new set of CIBSE weather files for building performance simulation was recently developed to address the need for better quality solar data. These are essential for most building performance simulation applications, particularly for daylighting studies and low-energy building design, which requires detailed irradiation data for passive solar design and overheating risk analysis. The reliability of weather data becomes paramount when building performance is pushed to its limits. Findings illustrate how principles of good window design can be applied to a case study building, built to the Passivhaus standard, and how its expected performance is affected by the quality of solar irradiation data. Analyses using test reference years were most affected by changes in the solar radiation model (up to 8.3% points), whereas for design summer years the maximum difference was 1.7% points. Adopting the new model caused overheating risk to be classified as more severe using test reference years...

Lighting Research & Technology

Energy and Buildings, Aug 1, 2004

The evaluation of shading devices is generally carried out using a sequence of shadow-pattern ima... more The evaluation of shading devices is generally carried out using a sequence of shadow-pattern images showing the progression of solar penetration for particular times of the day or year. This approach can reveal when solar penetration may occur, say at the summer solstice, but it cannot give a quantitative measure of the degree and likelihood of solar penetration over a representative period of a full year. This paper describes a new image-based technique to quantify the effectiveness of shading devices. It is founded on predictions of direct solar irradiation using hourly meteorological data for a full year. In addition to numerical output, the technique produces synoptic images that reveal the spatial and temporal variation of solar irradiation. There are no practical limits on the scene geometry and buildings with thousands of individual shading elements can be evaluated. The technique is designed to be both fast and highly scalable making it suitable for the evaluation of a large number of design variants. This is demonstrated in the paper using a parametrically defined model of a complex roof shading system based on the Changi Airport Terminal 3 design. The 3600 fins that comprise the roof shading system were generated using a parametric scheme where the fin orientation has a random component. A total of 42 design variants of the roof shading system were evaluated using the new technique.

Astrophysical Letters Communications, 1988

De Montfort University Leicester Uk, 2000

JavaScript is disabled for your browser. Some features of this site may not work without it. ... ... more JavaScript is disabled for your browser. Some features of this site may not work without it. ... Your query "process variability" produced 1037 result(s). ... Daylight simulation : validation, sky models and daylight coefficients. ... This working paper looks at the development of women's professional employment in Europe before the active support of UEFA in the 1970s when two professional leagues operated in Italy to the present situation when Germany ... ... The emerging role of epigenetics in the aetiology of endometriosis. ... BACKGROUND. Endometriosis ...

Energies, 2016

This paper describes the reduced capacity of the inrush current suppressor using a matrix convert... more This paper describes the reduced capacity of the inrush current suppressor using a matrix converter (MC) in a large-capacity wind power generation system (WPGS) with two squirrel-cage induction machines (SCIMs). These SCIMs are switched over depending on the wind speed. The input side of the MC is connected to the source in parallel. The output side of the MC is connected in series with the SCIM through matching transformers. The modulation method of the MC used is direct duty ratio pulse width modulation. The reference output voltage of the MC is decided by multiplying the SCIM current with the variable control gain. Therefore, the MC performs as resistors for the inrush current. Digital computer simulation is implemented to confirm the validity and practicability of the proposed inrush current suppressor using PSCAD/EMTDC (power system computer-aided design/electromagnetic transients including DC). Furthermore, the equivalent resistance of the MC is decided by the relationship between the equivalent resistance and the capacity of the MC. Simulation results demonstrate that the proposed inrush current suppressor can suppress the inrush current perfectly.

With the current development towards increased daylighting in buildings and the related progress ... more With the current development towards increased daylighting in buildings and the related progress in daylight evaluation methods, real life monitoring data becomes an urgent need to better support our understanding of the link between daylight and visual comfort. A data collection methodology is presented that links the physical measurements, using luminance maps derived from High Dynamics Range images, with the collection of user perception data at office workstations. The methodology has been developed to facilitate long-term monitoring of visual comfort in real world working environments. The measurement setup represents a compromise, i.e. the measurement position is not as ideal as that in a laboratory environment, but nevertheless provides useful data for situations where the laboratory approach is not viable. It thus opens a wider range of environments for visual comfort studies.

13Th International Radiance Workshop 2014, Jul 29, 2014

Energy and Buildings, 2003

This paper describes a novel approach for evaluating the total annual/monthly irradiation inciden... more This paper describes a novel approach for evaluating the total annual/monthly irradiation incident on building facades in urban settings. The analysis is founded on a physically-based rendering approach and uses data-visualisation techniques to generate 'maps' (i.e. false-colour images) of annual/monthly irradiation. The irradiation 'maps' are derived from hourly time-series data for 1 year and take accurate account of shading by, and inter-reflection from, other buildings and surfaces. The sun and sky irradiation images are evaluated separately. The sky contribution is calculated using realistic, non-isotropic models for the sky radiance distribution. The 'maps' can be used to confidently identify facade-locations where there is high irradiation, for example to aid the siting of photovoltaic (PV) panels. The technique can be applied to scenes of arbitrary complexity from a single building to fully 'worked-up' city models. The results of the analysis have been linked to a geographical information system (GIS)-based solar energy planning system. The system is targeted at city planners and one of its aims is to encourage the consideration of solar energy in the urban planning process.

13Th International Radiance Workshop 2014, Aug 24, 2014

Book of Abstracts from the 6th International Urban Design, 2013

Mortimer/Electrochromic Materials and Devices, 2013

The energy demands of food retail buildings account for approximately 3% of the UK’s energy consu... more The energy demands of food retail buildings account for approximately 3% of the UK’s energy consumption and resultant carbon emissions. Previous studies demonstrate that the greatest component of the electricity demand of food retail buildings is the cooling demand of the food refrigeration systems (ranging from 30 to 50%). Therefore a better understanding of the electricity demand for refrigeration would enable the development of effective energy management tools, including the evaluation of service and maintenance interventions to reduce operational electricity demand. Various methodologies have been developed and employed in the past for the quick identification of faults during the operation of commercial refrigeration systems. The focus of these methodologies has traditionally been on the temperature of food on the shop floor. The aim of this work is to enhance the existing fault-finding methodologies employed by a global multichannel retail organization, by enabling the identi...

Journal of Sea Research, 1997

The population dynamics of a marine zooplankton species in the Fair Isle Current off northern Sco... more The population dynamics of a marine zooplankton species in the Fair Isle Current off northern Scotland have been investigated by modelling and field study. An age-and weight-structured model of a population of the copepods Culanus jinmarchicus and Calanus helgolandicus was embedded in a biomass based ecosystem model comprising nutrients, phytoplankton, and other non-Calanus zooplankton. The mode1 was configured to represent a Lagrangian water column drifting in the Fair Isle Current off the north of Scotland during June 1988, with physical characteristics derived from the results of a three-dimensional hydrodynamic model of the northwest European shelf. The time-series results from the model were compared to data from a semi-synoptic field study by assuming the system to be short-term steady state and transposing the spatially resolved field observations into pseudo-time series along the modelled column drift track. The hydrodynamic model correctly reproduced the general physical characteristics of the system which were destratification of an initially stratified water column as a result of advection through a tidally energetic mixing zone, and subsequent re-establishment of stratification with distance downstream. The biological components of the model were broadly successful at reproducing the main features of the phytoplankton biomass response to the physical processes. The field data indicated that, despite the short-term changes in phytoplankton abundance along the drift track, the stage composition and biomass of the Calanus population was relatively stable. However, the model revealed that the main diagnostic features of the response were at the individual level, reflected in the weight at age distribution and reproductive output. The study highlights the difficulty of obtaining adequate data for testing complex models of zooplankton responses to short-term spatio-temporal variations in physical forcing.