Prof. Ljubomir Jankovic
University of Hertfordshire
College Lane, Hatfield
AL10 9AB,
United Kingdom
+447932176444
Region:
Honorarium:
Ljubomir “Lubo” Jankovic has spent the past 35 years focusing on how environmental design of buildings can be improved using dynamic simulation, instrumental performance monitoring and utilisation of bio-based materials.
Since 2018, he has held a position of Professor of Advanced Building Design at the University of Hertfordshire, UK, where he leads Zero Carbon Lab and is Director of the university-wide transdisciplinary Centre for Future Societies Research. Previously, he was Professor of Zero Carbon Design at Birmingham City University, UK, where he founded a Master’s programme on Zero Carbon Architecture and Retrofit Design. He also taught Behaviour of Complex Systems and Virtual Reality at the University of Birmingham and Embracing Complexity in Science and Society at the Universities of Liverpool and Salford. He has been a mentor of several PhD dissertations and a PhD Examiner in Spain, India, Pakistan and the UK.
His work on Designing Zero Carbon Buildings has contributed to the industry with monographs published in 2012, 2017, and the most recent one in press for 2024. His outputs in sustainable retrofitting are based on design and experimental performance evaluation and are widely cited. His work on reducing simulation performance gap has earned him a unique reputation in industry in designing buildings with hempcrete as a construction material. His work on changing the culture of building simulation from top-down to self-organised bottom-up approaches to computational fluid dynamics has introduced new thinking into industry. And his work on non-invasive experimental measurement of building physics properties has introduced a new method for quality control of building retrofit. Lubo’s invention of a new predictive control method for building heating and cooling utilises a compact genetic algorithm for machine learning of building physics properties, runs on a pocket size device and has a 30% energy reduction potential. The above outputs are in the context of £10+million of his research grant funding, with circa 120 publications and 900 citations.
Lubo is a founding Director of two innovation companies pioneering sustainability solution for buildings and has worked as a consultant in over 40 engineering projects, delivering numerous solutions for industry. This included improving thermal comfort in buildings and resolving simulation performance gap occurring in buildings built from hemp-lime bio-composite materials, and on designing thermal performance of commercial buildings built from that material.
He graduated as a Dipl. Ing. (now an MSc) from the University of Belgrade and was awarded a PhD from the University of Birmingham, both in Mechanical Engineering, having submitted his Doctoral Thesis on Solar Energy Monitoring, Control and Analysis in Buildings. He is a UK Chartered (Licensed) Engineer, a member of CIBSE, a Member of ASHRAE, a Fellow of the Institution of Analysts and Programmers, and a Fellow of the International Building Performance Simulation Association. His Society activities included various chapter roles, including positions of President of ASHRAE UK London and Southeast Chapter and Vice-President of ASHRAE UK Chapter.
Lubo is also an on-going student of applied fluid dynamics, pursued through his role as a certified water ski instructor and a passionate water skier.
Topic
How can we be sure that we get what is says on the tin? (Intermediate)
(How can we be sure that the envelope properties of a constructed building correspond to manufacturer’s specifications before construction?)
Buildings contribute to nearly 30% of global carbon dioxide emissions, making a significant impact on climate change. Despite advanced design methods, such as those based on dynamic simulation tools, a significant discrepancy exists between designed and actual performance. This so-called performance gap occurs as a result of many factors, including the discrepancies between theoretical properties of building materials and properties of the same materials in use, reflected in the physics properties of the entire building. There are several different ways in which building physics properties and the underlying properties of materials can be established: a co-heating test, which measures the overall heat loss coefficient of the building; a dynamic heating test, which, in addition to the overall heat loss coefficient, also measures the effective thermal capacitance and the time constant of the building; and a simulation of the dynamic heating test with a calibrated simulation model, which establishes the same three properties in a non-disruptive way in comparison with the actual physical tests. This lecture introduces a method of measuring building physics properties through actual and simulated dynamic heating tests. It gives insights into the properties of building materials in use, and it documents significant discrepancies between theoretical and measured properties. It introduces a quality assurance method for building construction and retrofit projects, and it explains the application of results on energy efficiency improvements in building design and control. It calls for re-examination of material properties data and for increased safety margins in order to make significant improvements in building energy efficiency.
Recommended audience:
ASHRAE members, students, architects, property developers, etc.
What Happens When We Sneeze? (Basic)
This lecture introduces experiments with self-organised simulation of movement of infectious aerosols in buildings. The ultimate aim of sustainability in buildings gained an additional new dimension as the start of the year 2020 saw a rapid worldwide spread of the infectious disease caused by a coronavirus named COVID-19. There is evidence that, in addition to person-to-person contact, the disease transmission occurred through airborne droplets/aerosols generated by breathing, speaking, coughing or sneezing. For that reason, building heating, ventilating and air conditioning systems can play an important role, as they may both contribute to, as well as reduce the transmission risk. However, there is insufficient understanding of the movement of infectious aerosols in buildings. Instead of modelling with Navier-Stokes equations, which take a long time to prepare and run, an alternative approach is introduced, that simulates the movement of particles in the way they behave in nature. As particles do not ‘know’ how to solve systems of equations, a method of bottom-up emergent modelling of the movement of infectious aerosols in internal space is developed using a physics games engine. Each particle is governed by a balance of forces acting on that particle, and the interaction between the particles and the environment gives rise to an emergent model that is not explicitly programmed. The results of simple simulation experiments in a conceptual auditorium show that the smallest droplets that are large enough to contain the virus can be suspended in the air for an extended period of time; that turbulent air flow can contribute to the infectious aerosols remaining in the room; and that unidirectional air flow can contribute to purging the room of the infectious aerosols. ASHRAE guidance is used for UV deactivation of viruses, combined with controlled air movement that takes the particles towards the UV sources. The learning outcome from this lecture is an increased understanding of the movement of infectious aerosols in buildings that provides insights for increased sustainability of building design.
Recommended audience:
ASHRAE members, students, architects, property developers, building stakeholders, policy makers.
Designing Zero Carbon Buildings - Embodied and Operational Emissions in Achieving True Zero (Basic)
The lecture introduces a structured approach to designing zero carbon buildings, taking into account embodied and operational emissions. The way we design zero carbon buildings starts with making design decisions about the site, geometry, thermal insulation, solar gain, solar shading, thermal mass, ventilation and integration of daylight with electrical lighting. By integrating all these aspects and by balancing the need for heating and cooling, we achieve thermal comfort for building occupants. We then put all of this into number-crunching simulation and optimisation tools, which enable us to harmonise design parameters and squeeze every ‘gram’ of performance. As a result, we obtain renewable energy requirements that balance carbon emissions arising from the combination of design parameters and requirements for heating and cooling. Thus, zero emissions are achieved, and the problem is solved. What more could be there to talk about? Except there is an elephant in the room. If we don’t take embodied emissions into account, we can overshoot the time when zero emissions are expected to be achieved by three to four decades. For that reason, embodied and operational emissions are combined into a Zero Equation to assess the requirements for achieving zero cumulative emissions by a specified year. A working example of a building is introduced, where construction materials, HVAC equipment and renewable energy systems are analysed in detail for embodied emissions. The effects of carbon storage in biomaterials and uncertainties of available data are discussed. The lecture introduces a workflow that enables designers to achieve zero carbon buildings with certainty and by a specified year.
Recommended audience:
ASHRAE members, students, architects, property developers, building stakeholders, policy makers, etc.
Sustainable retrofitting - Lessons learnt from design, off-site construction and performance analysis of deep energy retrofit of residential buildings (Basic)
The lecture introduces a process of deep energy retrofit carried out on a residential building in the UK, using an approach in which the existing building is completely surrounded by a new thermal envelope. It reports on the entire process, from establishing the characteristics of the existing building, carrying out design simulations, documenting the off- site manufacture and on-site installation, and carrying out instrumental monitoring, occupant studies and performance evaluation. Multi-objective optimisation is used throughout the process, for establishing the characteristics of the building before the retrofit, conducting the design simulations, and evaluating the success of the completed retrofit. Building physics parameters before and after retrofit are evaluated in an innovative way through simulation of dynamic heating tests with calibrated models - a method that can be used as quality control measure in other retrofit programmes. New insights are provided into retrofit economics in the context of occupants’ health and wellbeing improvements. The wide scope of the lessons learnt can be instrumental in the creation of continuing professional development programmes, university courses, and public education that raises awareness and demand. These lessons can also be valuable for development of new funding schemes that address the outstanding challenges and the need for updating technical reference material, informing policy and building regulations.
Recommended audience:
ASHRAE members, students, architects, property developers, building stakeholders, policy makers.
How to get over the gap? (Advanced)
The lecture introduces a method for reducing simulation performance gap using digital filtering of building simulation outputs. Mainstream dynamic simulation tools used by designers do not have a built-in capability to accurately simulate the effect of building materials in use, especially that of hemp-lime construction material (hempcrete). Due to the specific structure of the hemp-lime construction material, heat travels via a maze of solid parts, which create encapsulated capillary tubes between these parts. The resultant heat and moisture transfer, combined between the solid parts and the capillary tubes, cannot be fully represented in mainstream simulation tools, causing a significant performance gap between the simulation and actual performance after the building is constructed. The lecture explains the development of an analysis method, based on a numerical procedure for digital signal filtering using Fourier series. It introduces experimental validation using the results of a post-occupancy research project. The application of this method on buildings in the design stage achieves the results that are equivalent to instrumental monitoring of that building that hasn’t yet been constructed. As a performance gap between design simulation and actual buildings occurs in relation to all building materials, this method has a wide scope of application in reducing the performance gap.
Recommended audience:
ASHRAE members, students, architects, property developers, etc.
The Zero Equation - Determining building emissions status in future years (Basic)
The lecture introduces results of research that revealed a significant delay in achieving zero cumulative emissions, if embodied emissions are not taken into account. This inspired the development of a Zero Equation, to answer the question: When is a building going to achieve zero cumulative emissions, consisting of embodied and operational emissions? The Zero Equation is first explained using an analogy with a jam jar and spoons, in order to communicate its concept to a wider audience. Subsequently, it is introduced as a mathematical formula and applied in several case studies. In addition to determining the building emission status in future years, a derivative of the Zero Equation is used to determine by how much a renewable energy system needs to be expanded in order to achieve zero cumulative emissions within a specified number of years. The lecture then demonstrates the application of the Zero Equation in several case studies of newbuild and retrofitted buildings, including the ASHRAE New Global Headquarters, establishing the time when these buildings will achieve cumulative zero emissions.
Recommended audience:
ASHRAE members, students, architects, property developers, building stakeholders, policy makers, etc.
