All posts by Andrea Ferrantelli

Theoretical physicist and musician. Quantum Prana, the Dark Matter Guitar.
Energy, Engineering, Physics, Science

New paper on energy efficiency published

Leave a comment

A new paper on the energy efficiency of buildings (here, ice hockey halls) is now published!

Title:
Energy analysis in ice hockey arenas and analytical formula for the temperature profile in the ice pad with transient boundary conditions

Abstract:
The energy efficiency of ice hockey arenas is a central concern for the administrations, as these buildings are well known to consume a large amount of energy. Since they are composite, complex systems, solutions to such a problem can be approached from many different areas, from managerial to technological to more strictly scientific. In this paper we consider heat transfer processes in an ice hockey hall, during operating conditions, with a bottom-up approach based upon on-site measurements. Detailed heat flux, relative humidity and temperature data for the ice pad and the indoor air are used for a heat balance calculation in the steady-state regime, which quantifies the impact of each single heat source. We also solve the heat conduction equation for the ice pad in transient regime, and obtain a general analytical formula for the temperature profile that is suitable to practical applications. When applied to the resurfacing process for validation, it shows good agreement with an analogous numerical solution. Since our formula is given with implicit initial condition and boundary conditions, it can be used not only in ice hockey halls, but in a large variety of engineering applications.

https://www.tandfonline.com/eprint/kKUN792Us3j7QVgTpMpB/full?target=10.1080/17512549.2019.1615549

Energy, Engineering, Physics, Science

Paper on energy efficiency in buildings now published

Leave a comment

Our paper “A combined analytical model for increasing the accuracy of heat emission predictions in rooms heated by radiators” is now published on the Journal of Building Engineering. Here is the link to the pdf (free download for the next 50 days):

https://www.sciencedirect.com/science/article/pii/S235271021831413X?dgcid=author

Abstract:

The efficiency of heat emitters plays an important role in the improvement of building energy performance, especially in the context of system and product comparison. In particular, it can be directly related to thermal comfort via the operative temperature that is effectively sensed by the users.
For the first time in the literature, in this paper we develop a combined analytical model for room and radiator that computes directly the heat output required to maintain a specific operative temperature. The total heat balance of the enclosure is used to accurately quantify and compare the heat emission losses of different radiator types via an analytical calculation of the operative temperature. This determines the efficiency of a selection of panel radiators with different surface temperature, radiation fraction and number of panels, which were tested in a chamber conforming to the EN 442-2 standard.
Additionally, we assess the related annual energy consumption in different climates by carrying out annual simulations in old (without heat recovery) and new (with heat recovery) building types located in Tallinn, Estonia and Strasbourg, France. In the new building we find a similar performance for all the radiators. In the old building however, one radiator outperforms the other two with up to 1.38% lower annual energy consumption, due to smaller rear losses and higher thermal comfort provided by the larger front panel surface.

Uncategorized

New paper on energy engineering published today

Leave a comment

Cheers!

I have just published a new article entitled “Optimization of Radiators, Underfloor and Ceiling Heater Towards the Definition of a Reference Ideal Heater for Energy Efficient Buildings”. We discuss analytical methods for optimization of heating systems in residential buildings, providing a formal efficiency analysis and some specific optimal configurations.
Here I am using a simple analytical method that I have developed some time ago for a different topic (predicting hot water consumption in residential buildings).
You can view the article (with open access) and download it for free at the following address:
https://www.mdpi.com/2076-3417/8/12/2477

Abstract:
Heat emitters, as the primary devices used in space heating, cover a fundamental role in the energy efficient use of buildings. In the search for an optimized design, heating devices should be compared with a benchmark emitter with maximum heat emission efficiency. However, such an ideal heater still needs to be defined. In this paper we perform an analysis of heat transfer in a European reference room, considering surface effects of thermal radiation and computing the induced operative temperature (op.t.) both analytically and numerically. Our ideal heater is the one determining the highest op.t. By means of functional optimization, we analyse trends such as the variation of operative temperature with radiator panel dimensions, finding optimal configurations. To make our definitions as general as possible, we address panel radiators, convectors, underfloor (UFH) and ceiling heater. We obtain analytical formulas for the operative temperature induced by panel radiators and identify the 10-type as our ideal radiator, while the UFH provides the best performance overall. Regarding specifically UFH and ceiling heaters, we find optimal sizes providing maximum op.t. The analytical method and qualitative results reported in this paper can be generalized and adopted in most studies concerning the efficiency of different heat emitter types in building enclosures.

cosmology, Engineering, philosophy, Physics, Science

Philosophy paper “Epistemological Explanation of Lean Construction” now published

Leave a comment

Cheers!

You might already know that I’m very fond of philosophy. I loved it immediately, as soon as I started my studies in high school in Italy, back in the 90s. I certainly refer to it in my daily life, more or less explicitly; after all, my entire Quantum Prana concept is based on the interaction between Eastern and Western traditions.

Interestingly enough though, sometimes it happens that you don’t see a tangible outcome of your studies for a long period of time. Perhaps, even for over two decades.
And in fact, here it is! A paper entitled “Epistemological Explanation of Lean Construction” that I wrote together with my colleagues at Aalto University, Finland and at the University of Huddersfield, UK.

My contribution consists of a short review and comparison of the classical epistemology of Plato and Aristotle. I then explain how their differences got enhanced through the centuries, until the debate between the Rationalists (René Descartes, Baruch Spinoza, and Gottfried Wilhelm Leibniz) and the British Empiricists (John Locke, George Berkeley, and David Hume), commenting also on their role in cosmology.

I then move forward by shortly analyzing some features of the epistemology of Edmund Husserl and Martin Heidegger, in relation with tacit knowledge and Japanese philosophy.

At this webpage you can read our paper for free or download it in PDF:

https://ascelibrary.org/doi/10.1061/%28ASCE%29CO.1943-7862.0001597

cosmology, particle physics, Physics, Science, supergravity, Theoretical physics

Theoretical physics paper now published

Leave a comment

My article on reheating and gravitino production in MSSM inflation is now published in The European Physical Journal C. It is a full access publication, if you are interested you can find it here:

https://link.springer.com/article/10.1140/epjc/s10052-017-5269-8

Abstract

In the framework of MSSM inflation, matter and gravitino production are here investigated through the decay of the fields which are coupled to the udd inflaton, a gauge-invariant combination of squarks. After the end of inflation, the flat direction oscillates about the minimum of its potential, losing at each oscillation about 56% of its energy into bursts of gauge/gaugino and scalar quanta when crossing the origin. These particles then acquire a large inflaton VEV-induced mass and decay perturbatively into the MSSM quanta and gravitinos, transferring the inflaton energy very efficiently via instant preheating. Regarding thermalization, we show that the MSSM degrees of freedom thermalize very quickly, yet not immediately by virtue of the large vacuum expectation value of the inflaton, which breaks the SU(3)C×U(1)YSU(3)C×U(1)Y symmetry into a residual U(1). The energy transfer to the MSSM quanta is very efficient, since full thermalization is achieved after only O(40)O(40) complete oscillations. The udd inflaton thus provides an extremely efficient reheating of the Universe, with a temperature Treh=O(108GeV)Treh=O(108GeV), which allows for instance several mechanisms of baryogenesis. We also compute the gravitino number density from the perturbative decay of the flat direction and of the SUSY multiplet. We find that the gravitinos are produced in negligible amount and satisfy cosmological bounds such as the Big Bang nucleosynthesis (BBN) and dark matter (DM) constraints.

Engineering, Materials science, Physics, Science, Soft matter

My new article on materials science

Leave a comment

Here is my newest paper!

“Thermomechanical generation of fissure patterns on the surface of heated circular wood samples”

https://arxiv.org/abs/1709.03546

We discuss the observation of primary crack patterns on the surface of heated medium density fiberboard (MDF) round samples in inert atmosphere. A constant heat flux irradiates the wood surface, and the primary cracks seem to appear instantaneously at a temperature below the pyrolysis point, \textit{before} any actual charring. Such fissures were originally believed to form mainly by the action of physicochemical processes; on the contrary, we show here that below the pyrolysis temperatures this occurs by means of thermomechanical surface instability. The crack patterns can indeed be explained qualitatively by the simultaneous thermal expansion and softening of the hot surface layer, which is restrained by the colder wood beneath. This generates membrane compressive stresses leading to surface instability. Physically, this is a consequence of the thermomechanical properties of wood, which is a natural thermoplastic. In this paper, the macro-crack topology is reproduced by a full 3D thermomechanical instability model. We obtain the patterns by solving the according eigenvalue problem numerically, by Finite Element Method (FEM). We also formulate the model in 2D, assuming a circular soft thin plate bonded to an elastic foundation, and solve it both analytically and numerically. Finally, we compare our results with analogous crack patterns appearing on the surface of square samples, which we discussed in a previous study. We conclude that very different pattern symmetries (orthotropic, isotropic and circular) might be explained by the same model of thermomechanical surface instability.

Energy, Engineering, Science

Slides for my talk on analytical modelling of energy consumption

Leave a comment

Domestic Hot Water (DHW) is an important source of energy consumption for any type of building. I attach here the slides of a short (20 mins) talk I gave on this topic yesterday, at the Energy7 conference in Manchester UK:

Analytical modelling and prediction formulas for domestic hot water consumption – slides

I briefly outline an analytical bottom-up method to model DHW consumption accurately. We

 1) derive the correlations between occupant groups and different seasons => MAIN TREND OF CONSUMPTION
 2) generate a PREDICTIVE FORMULA for the DHW consumption of unknown occupant groups.

The slides are in PDF format (just use the pgup/pgdn keys on your keyboard to scroll). The talk is based on a paper I published last Spring, described in this entry of my blog.

Greetings from Manchester!

Engineering, philosophy, Science

ON EPISTEMOLOGY OF CONSTRUCTION ENGINEERING AND MANAGEMENT

Leave a comment

Here is the short version (conference proceedings) of our epistemology paper, discussing how Plato’s and Aristotle’s methodologies affected engineering practice, research and education during the last two centuries.

Click to access iglc-f15a7a9d-3917-4eed-ac33-1549c1719305.pdf

—
As a polemical side note, this shows that, contrary to some well-established pedagogical practice, you should not study at school only what you’ll need for your day job (call it Anglo-saxon, or Nordic Pragmatism).
Let me thus praise my high school formation in Italy, where three years of demanding *compulsory* philosophical studies allowed me, 20 years later, to write this paper ).