598 lines
26 KiB
TeX
598 lines
26 KiB
TeX
\section{CARNOT model}\label{sec:CARNOT}
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In order to better analyze the different model training and update methods it
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was decided to replace the physical \pdome\ building with a computer model.
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This allows for faster-than-real-time simulations, as well as perfectly
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reproducing the weather conditions and building response for direct comparison
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of different control schemes over long periods of time.
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The model is designed using the CARNOT
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toolbox~\cite{lohmannEinfuehrungSoftwareMATLAB} for Simulink. It is based on the
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CARNOT default \textit{Room Radiator} model, with the following canges:
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\begin{itemize}
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\item Only one of the two default rooms is used
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\item The outside walls are replaced with windows
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\item A window is added on the roof as an equivalent for the four skylights
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presented in Section~\ref{sec:Physical_dimensions}
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\end{itemize}
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The resulting schema for the \pdome\ building is presented in
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Figure~\ref{fig:CARNOT_polydome}. The following sections will focus on detailing
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the choice of all the necessary model parameters.
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\begin{figure}[ht]
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\centering
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\includegraphics[width = \textwidth]{Images/polydome_room_model.pdf}
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\caption{Simulink Schema of the CARNOT \pdome\ building model}
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\label{fig:CARNOT_polydome}
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\end{figure}
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\clearpage
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The Simulink model is then completed by adding a \textit{Weather Data File}
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containing weather measurements for a whole year, and a \textit{Weather
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Prediction} block responsible for sending weather predictions to the MPC.\@ The
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controller itself is defined in Python and is connected to Simulink via three
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TCP/IP sockets. Details on the implementation are presented in
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Section~\ref{sec:implementation}.
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\subsection{Physical dimensions}\label{sec:Physical_dimensions}
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The \pdome\ building is a dome-shaped, single-zone building serving the role
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of classroom for audiences of around one hundred students.
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Most of the necessary measurements are already available from the
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\citetitle*{nattererPolydomeTimberShell1993} article by
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\textcite{nattererPolydomeTimberShell1993}. It presents the \pdome\ geometry as
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having a floor area of 25m $\times$ 25m, a maximum height of the building of 7m,
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walls of a maximum height of 3m. The roof is a spherical cap with a radius of
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approximately 28m.
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One particularity of the \pdome\ is the presence of four large skylights on the
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roof. An estimate of their size has been made using images from \textit{Google
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Maps Satellite View}~\cite{GoogleMaps}, with the included measurement tool. These
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measurements are presented in Figure~\ref{fig:Google_Maps_Skylights}. The
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skylights are measured to be squares of edge 2.5m.
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\begin{figure}[ht]
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\centering
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\includegraphics[width = 0.8\textwidth]{Images/google_maps_polydome_skylights}
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\caption{Google Maps Satellite view of the \pdome\ building}
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\label{fig:Google_Maps_Skylights}
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\end{figure}
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The only remaining missing piece of information is the \textit{stem wall}
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height, which is the height of the walls from the ground on which the dome
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ceiling directly resides. Due to the limited campus access, this measure has
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also been approximated from a Google Maps image, presented in
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Figure~\ref{fig:Google_Maps_Streetview}. An object of known size has been used
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as reference, after which the following measurements have been done in
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\citetitle{kimballGIMPGNUImage}~\cite{kimballGIMPGNUImage} using the
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\textit{Measure Tool}.
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The chosen reference object is the \pdome\ HVAC system, the full description of
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which is presented in Section~\ref{sec:HVAC_parameters}, and which has a known
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height of 2061mm \cite{aermecRoofTopManuelSelection}.
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\begin{figure}[ht]
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\centering
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\includegraphics[width = \textwidth]{Images/polydome_streetview_annotated}
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\caption{Google Maps StreetView view of the \pdome\ building}
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\label{fig:Google_Maps_Streetview}
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\end{figure}
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The graphical analysis resulted in the measurements presented in
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Table~\ref{tab:GIMP_measurements}:
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\begin{table}[ht]
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%\vspace{-8pt}
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\centering
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\begin{tabular}{||c c c c||}
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\hline
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Object & Size [px] & Size[mm] & Size[m]\\
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\hline \hline
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HVAC height & 70 & 2100 & 2.1 \\
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Building height & 230 & 6900 & 6.9 \\
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Stem wall & 45 & 1350 & 1.35 \\
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Dome height & 185 & 5550 & 5.55 \\
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\hline
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\end{tabular}
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\caption{Calculated Dome Dimensions}
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\label{tab:GIMP_measurements}
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\end{table}
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For a validation of the results shown in Figure~\ref{tab:GIMP_measurements} it
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is possible to compare the total \pdome\ building height measured in GIMP with
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the value presented beforehand. The graphical measure of 6.9m is indeed very
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close to the described height of 7m.
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These measurements can be used to set the size parameters of all the nodes in
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the model:
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\begin{itemize}
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\item Side windows with a size of 2m $\times$ 25m each
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\item Roof window with a size of 5m $\times$ 5m, cumulative surface of all
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the skylights
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\item Ceiling with a size of 25m $\times$ 25m
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\item Floor with a size of 25m $\times$ 25m
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\end{itemize}
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\subsection{Internal volume}
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The \pdome\ building has a structure that is mostly based on a dome shape, with
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the difference that the dome portion of the building does not reach the ground,
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but stands above it at a height of $\approx 1.35m$ (cf.
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Table~\ref{tab:GIMP_measurements}), with the large side windows extending to the
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ground and creating a \textit{stem wall} for the dome to sit on.
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The total internal volume of the \pdome\ building can therefore be approximated
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by computing the sum volumes of the two elements: the stem and the dome.
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Geometrically, a dome is a portion of a sphere cut off by a plane. Its volume
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can therefore be computed in a similar fashion to that of a complete sphere.
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A sphere can be regarded as volume of rotation of function $f(x)$ (cf.
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Equation~\ref{eq:rot_func}) around the x axis, where $R$ is the sphere radius
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and $x \in [0, 2r]$:
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\begin{equation}\label{eq:rot_func}
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f(x) = \sqrt{R^2 - (x-R)^2} = \sqrt{2Rx - x^2}
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\end{equation}
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It is therefore possible to compute the volume of a dome by integrating $f(x)$
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up to the dome height $h$, as presented in Equation~\ref{eq:rot_vol}.
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\begin{equation}\label{eq:rot_vol}
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\begin{aligned}
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V &= \pi \int_0^h f(x)^2 dx \\
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&= \pi \int_0^h (2Rx - x^2)dx \\
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&= \pi \left( Rx^2 - \frac{1}{3}x^3 \right)_0^h \\
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&= \frac{\pi h^2}{3} (3R - h) \\
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\end{aligned}
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\end{equation}
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The volume of the \pdome\ dome is computed by first finding the radius of the
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complete sphere, the radius of curvature (cf.
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Equation~\ref{eq:radius_curvature}, where $h$ is the height of the dome and $r$
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is the radius of the base of the dome) and plugging it in
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Equation~\ref{eq:rot_vol}.
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\begin{equation}\label{eq:radius_curvature}
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R_c = \frac{r^2 + h^2}{2h}
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\end{equation}
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The volume of the dome is then given by:
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\begin{equation}
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V_d = \frac{1}{3} \pi h^2 (3R_c - h) = \frac{1}{6} \pi h (3r^2 + h^2)
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\end{equation}
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The stem of the \pdome\ is approximated to a cube of edge 25m, and its volume can
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therefore be calculated as:
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\begin{equation}
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V_s = l_s^2 * h_s
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\end{equation}
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The total volume of the building is then given as:
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\begin{equation}
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V = V_d + V_s = \frac{1}{6} \pi h (3r^2 + h^2) + l_s^2
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\end{equation}
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Numerically, considering a dome diameter of 28m, a dome height of 5.55m and a stem
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wall edge of 25m, we get the approximate volume of the building:
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\begin{equation}\label{eq:numerical_volume}
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V = V_d + V_s = 1798.22m^3 + 843.75m^3 = 2641.97m^3 \approx 2650m^3
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\end{equation}
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The value presented in Equation~\ref{eq:numerical_volume} is used directly in
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the \textit{room\_node} of the CARNOT model (cf.
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Figure~\ref{fig:CARNOT_polydome}), as well as the calcualtion of the Air
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Exchange Rate, presented in Section~\ref{sec:Air_Exchange_Rate}.
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\subsection{Furniture}
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The main function of the \pdome\ building is serving as a classroom for around
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one hundred students. It has wood furniture consisting of chairs and tables, as
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well as a wooden stage in the center of the building, meant to be used for
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presentations. The building also contains a smaller room, housing the all the
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necessary technical equipment (cf. Figure~\ref{fig:Google_Maps_Streetview}).
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The most accurate way of including information on the furniture in the CARNOT
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model would be to manually compute the mass, volume and materials for each of
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the chairs, tables, etc.\ but due to the restricted access to the building a
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simpler approximation has been made.
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\textcite{johraNumericalAnalysisImpact2017} present a methodology to model the
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furniture in buildings for multiple different materials, as well as an
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\textit{equivalent indoor content material} that is meant to approximate the
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furniture content of an office building. These values for mass content, surface
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area, material density and thermal conductivity have been taken as the basis for
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the \pdome\ furniture content approximation, with the assumption that, since the
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\pdome\ is still mostly empty, it has approximately a quarter of the furniture
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present in a fully furnished office.
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The full set of furniture is therefore approximated in the CARNOT model as a
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wall, with the numerical values for mass, surface, thickness and volume
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presented below.
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\subsubsection*{Surface}
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% surface:
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% 1/4 * 1.8 [m2/m2 of floor space] * 625 m2 surface = 140 m2
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% 140 m2 = [7 20] m [height width]
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The equivalent material is taken to have a surface of 1.8 $m^2$ per each $m^2$
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of floor area~\cite{johraNumericalAnalysisImpact2017}. With a floor area of 625
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$m^2$, and assuming the furnishing of the building is a quarter that of a
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fully-furnished office, the \pdome\ furniture equivalent wall has a surface area
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of:
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\begin{equation}
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S_f = \frac{1}{4} \cdot 1.8 \left[\frac{\text{m}^2}{\text{m}^2}\right]
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\cdot 625\ \left[\text{m}^2\right] = 140\ \left[\text{m}^2\right]
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\end{equation}
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\subsubsection*{Mass}
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% mass:
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% 1/4 * 40 [kg/m2 of floor space] * 625 m2 surface = 6250 kg
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The mass of the furniture equivalent wall is computed using the same
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methodology, considering 40 kg of furniture mass per $m^2$ of floor surface.
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\begin{equation}
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M_f = \frac{1}{4} \cdot 40 \cdot 625\ \left[\text{m}^2\right] = 6250\
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\left[\text{m}^2\right]
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\end{equation}
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\subsubsection*{Volume}
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% volume:
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% 6250[kg]/600[kg/m3] = 10.41 [m3]
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The volume of the furniture equivalent wall is calculated with the help of the
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equivalent mass and densities:
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\begin{equation}
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V_f = \frac{M_f}{\rho_f} = \frac{6250}{600}
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\left[\frac{\text{kg}}{\text{kg}/\text{m}^3}\right]
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= 10.41\ \left[\text{m}^3\right]
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\end{equation}
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\subsubsection*{Thickness}
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% thickness:
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%10.41[m3]/140[m2] = 0.075m = 7.5cm
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The last parameter of the furniture equivalent wall is computed by dividing its
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volume by the surface:
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\begin{equation}
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h_f = \frac{V_f}{S_f} = \frac{10.41}{140} \left[\frac{m^3}{m^2}\right] =
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0.075\ \left[\text{m}\right] = 7.5\ \left[\text{cm}\right]
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\end{equation}
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\subsection{Material properties}
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In order to better simulate the behaviour of the real \pdome\ building it is
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necessary to approximate the building materials and their properties as close as
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possible. This section goes into the detailes and arguments for the choice of
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parameters for each of the CARNOT nodes' properties.
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\subsubsection{Windows}
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The windows are supposed to be made of two glass panes of thickness 4mm each.
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The values of the heat transfer coefficient (U-factor) can vary greatly for
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different window technologies, but an educated guess can be made on the lower
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and upper bounds based on the age and location of the building.
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Window manufacturers state
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the U-factor for double glass windows to be between 2.8 \(\frac{W}{m^2K}\) for
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older manufacturing techniques and 1.2 \(\frac{W}{m^2K}\) for newer
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models~\cite{WhatAreTypical2018}.
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The US Energy Department states that the
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typical U-factor values for modern window installations is in the range of 0.2
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--- 1.2 \(\frac{W}{m^2K}\)\cite{GuideEnergyEfficientWindows}.
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The European flat glass association claims that the maximum allowable U-factor
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value for new window installations in the private sector buildings in
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Switzerland is 1.5
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\(\frac{W}{m^2K}\)~\cite{glassforeuropeMinimumPerformanceRequirements2018}.
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Considering the aforementioned values, and the fact the the \pdome\ building was
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built in 1993~\cite{nattererModelingMultilayerBeam2008}, the default U-factor of
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1.8 \(\frac{W}{m^2K}\) has been deemed appropriate.
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The total solar energy transmittance $[g]$ and transmittance in the visible
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range $[v_g]$ can vary in the range of 0.1 --- 0.9 depending on manufacturing
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technology, tint, etc. The average values of 0.7 and 0.65 respectively have been
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chosen for this case.
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The values for glass density and heat capacity have been left at their default
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values of 2500 \(\frac{kg}{m^3}\) and 1008 \(\frac{J}{kgK}\) respectively.
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\subsubsection{Roof and Floor}
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%%% Roof
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% [5cm wood, 10cm insulation, 5cm wood]
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% Conductivity for each material
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% Heat capacity for each material
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% Density for each material
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The roof structure has been assumed to be made out of 10cm of insulation,
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enclosed on each side by 5cm of wood.
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%%% Floor
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% [5cm wood, 10cm insulation, 20cm concrete]
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% Conductivity for each material
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% Heat capacity for each material
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% Density for each material
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The floor composition has been taken as consisting of, from top to bottom, 5cm
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wood, 10cm insulation followed by 20cm of concrete.
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All the necessary values to characterise these materials have been taken
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from~\cite{BuildingsHeatTransferData} and are presented in
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Table~\ref{tab:material_properties}:
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\begin{table}[ht]
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%\vspace{-8pt}
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\centering
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\begin{tabular}{||c c c c||}
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\hline
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Material & Thermal Conductivity $[k]$ $[\frac{W}{mK}]$ & Specific Heat
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Capacity $[c]$ $[\frac{J}{kgK}]$ & Density $[\rho]$ $[\frac{kg}{m^3}]$
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\\
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\hline \hline
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Plywood & 0.12 & 1210 & 540 \\
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Insulation & 0.03 & 1200 & 40 \\
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Concrete & 1.0 & 700 & 2500 \\
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\hline
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\end{tabular}
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\caption{Material properties for roof and floor elements}
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\label{tab:material_properties}
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\end{table}
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\subsection{HVAC parameters}\label{sec:HVAC_parameters}
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The \pdome\ is equiped with an \textit{AERMEC RTY-04} HVAC system. According to
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the manufacturer's manual~\cite{aermecRoofTopManuelSelection}, this HVAC houses
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two compressors, of power 11.2 kW and 8.4 kW respectively, an external
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ventillator of power 1.67 kW, and a reflow ventillator of power 2 kW. The unit
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has a typical Energy Efficiency Ratio (EER, cooling efficiency) of 4.9 --- 5.1
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and a Coefficient of Performance (COP, heating efficiency) of 5.0, for a maximum
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cooling capacity of 64.2 kW.
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One particularity of this HVAC unit is that during summer only one of the two
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compressors are running. This results in a higher EER, in the cases where the
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full cooling capacity is not required.
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\subsubsection*{Ventilation}
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According to the manufacturer manual \cite{aermecRoofTopManuelSelection}, the
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HVAC unit's external fan has an air debit ranging between 4900
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$\text{m}^3/\text{h}$ and 7000 $\text{m}^3/\text{h}$.
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\subsubsection*{Air Exchange Rate}\label{sec:Air_Exchange_Rate}
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The air exchange rate, also known as `air changes per hour', represents the
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number of times the air in a room gets replaced with new air. It can be
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computed by dividing the air flow through the room by the room volume:
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\begin{equation}
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\text{Air exchange rate} = \frac{\text{Air flow}}{\text{Total volume}}
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\end{equation}
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In the case of the \pdome\ and its HVAC, this results in an airflow range of:
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\begin{equation}
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\begin{aligned}
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\text{Air exchange rate} &= \frac{4900}{2650}
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- \frac{7000}{2650} &\left[\frac{\text{m}^3/\text{h}}{\text{m}^3}\right]\\
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&= 1.85 - 2.64 &\left[\frac{1}{\text{h}}\right]
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\end{aligned}
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\end{equation}
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As it will be shown in Section~\ref{sec:CARNOT_experimental}, the external fan
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is continuously running. The \textit{Air exchange rate} has therefore been fixed
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to a value of 2.5 for the duration of the whole simulation. The real airflow
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could, of course, vary depending on a multitude of external factors, but they
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would require more precise measurements to estimate.
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\subsection{Validating against experimental data}\label{sec:CARNOT_experimental}
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In order to confirm the validity of the model it is necessary to compare the
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CARNOT models' behaviour against that of the real \pdome\ building.
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Section~\ref{sec:CARNOT_expdata} presents the available experimental data,
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Section~\ref{sec:CARNOT_WDB} details the transformation of the available data
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into CARNOT's WDB format, and Section~\ref{sec:CARNOT_comparison} details a
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qualitative analysis of the differences.
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\subsubsection{The available experimental data}\label{sec:CARNOT_expdata}
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All the experimental data used for the validation of the CARNOT model has been
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collected previously for another
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study~\cite{fabiettiMultitimeScaleCoordination2018}, where it has been used to
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identify a State Space model for the \pdome\ building.
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The data has been collected in the time span of June to August 2017, and is
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divided in seven different experiments, as presented in
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Figure~\ref{tab:exp_dates}. The available measurements are the \textit{Outside
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Temperature}, \textit{Solar Irradiation}, \textit{Electrical power consumption}
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of the HVAC, and two measurements of \textit{Inside Temperature} in different
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parts of the room.
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\begin{table}[ht]
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\centering
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\begin{tabular}{||c c c||}
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\hline
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Exp no. & Start Date & End Date\\
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\hline \hline
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1 & 01.06.2017 20:00 & 03.06.2017 17:00 \\
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2 & 10.06.2017 16:00 & 12.06.2017 06:00 \\
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3 & 16.06.2017 20:00 & 19.06.2017 06:00 \\
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4 & 19.06.2017 20:00 & 22.06.2017 06:00 \\
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5 & 30.06.2017 20:00 & 03.07.2017 06:00 \\
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6 & 07.07.2017 20:00 & 10.06.2017 06:00 \\
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7 & 13.06.2017 20:00 & 20.06.2017 06:00 \\
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|
\hline
|
|
\end{tabular}
|
|
\caption{\pdome\ experimental measurements}
|
|
\label{tab:exp_dates}
|
|
\end{table}
|
|
|
|
\clearpage
|
|
|
|
As mentioned previously, the external fan of the HVAC is constantly running.
|
|
This can be seen in Figure~\ref{fig:Polydome_electricity} as the electricity
|
|
consumption of the HVAC has a baseline of 1.67 kW of power consumption.
|
|
|
|
\begin{figure}[ht]
|
|
\centering
|
|
\includegraphics[width = \textwidth]{Plots/Fan_baseline.pdf}
|
|
\caption{Electrical Power consumption of the \pdome\ HVAC for Experiment 7}
|
|
\label{fig:Polydome_electricity}
|
|
\end{figure}
|
|
|
|
Figure~\ref{fig:Polydome_electricity} also gives an insight into the workings of
|
|
the HVAC when it comes to the combination of the two available compressors. The
|
|
instruction manual of the HVAC~\cite{aermecRoofTopManuelSelection} notes that in
|
|
summer only one of the compressors is running. This allows for a larger EER
|
|
value and thus better performance. We can see that this is the case for most of
|
|
the experiment, where the pwoer consumption caps at around 6 kW. There are,
|
|
however, moments during the first part of the experiment where the power
|
|
momentarily peaks over the 6 kW limit, and goes as high as around 9 kW. This
|
|
most probably happens when the HVAC decides that the difference between the
|
|
setpoint temperature and the actual measured values is too large.
|
|
|
|
Figure~\ref{fig:Polydome_exp7_settemp} presents the values of the setpoint
|
|
temperature and the measured internal temperature.
|
|
|
|
\begin{figure}[ht]
|
|
\centering
|
|
\includegraphics[width = \textwidth]{Plots/Exp_settemp.pdf}
|
|
\caption{Measured vs setpoint temperature of the HVAC for Experiment 7}
|
|
\label{fig:Polydome_exp7_settemp}
|
|
\end{figure}
|
|
|
|
A few observations can be made on these measurements. First, the second
|
|
compressor is indeed turned on during the first part of the experiment, when the
|
|
setpoint differs greatly from the measured temperature. Second, for the
|
|
beginning of Experiment 7, as well as the majority of the other experiments, the
|
|
setpoint temperature is the value that gets changed in order to excite the
|
|
system, and since the HVAC's controller is on during identification, it will
|
|
oscillate between using one or two compressors. Lastly, it is possible to notice
|
|
that the HVAC is not turned on during the night, with the exception of the
|
|
external fan, which runs continuously.
|
|
|
|
\subsubsection{The CARNOT WDB weather data format}\label{sec:CARNOT_WDB}
|
|
|
|
For a corect simulation of the building behaviour, CARNOT requires not only the
|
|
detailed definition of the building blocks/nodes, but also a very detailed set
|
|
of data on the weather conditions. This set includes detailed information on the
|
|
sun's position throughout the simulation (zenith and azimuth angles), the Direct
|
|
Normal Irradiance (DHI) and Direct Horizontal Irradiance (DNI), direct and
|
|
diffuse solar radiation on surface, as well as information on the ambient
|
|
temperature, humidity, precipitation, pressure, wind speed and direction, etc.
|
|
A detailed overview of each measurement necessary for a simulation is given in
|
|
the CARNOT user manual~\cite{CARNOTManual}.
|
|
|
|
In order to compare the CARNOT model's performance to that of the real \pdome\
|
|
it is necessary to simulate the CARNOT model under the same set of conditions as
|
|
the ones present during the experimental data collection. In order to do this,
|
|
all the missing values that are required by the simulation have to be filled. In
|
|
some cases, such as the sun angles it is possible to compute the exact values,
|
|
but in other cases the real data is not available, which means that is has to be
|
|
inferred from the available data.
|
|
|
|
The information on the zenith and azimuth solar angles can be computed exactly
|
|
if the position and elevation of the building are known. The GPS coordinates and
|
|
elevation information is found using a map~\cite{ElevationFinder}. With that
|
|
information available, the zenith, azimuth angles, as well as the angle of
|
|
incidence (AOI) are computed using the Python pvlib
|
|
library~\cite{f.holmgrenPvlibPythonPython2018}.
|
|
|
|
As opposed to the solar angles which can be computed exactly from the available
|
|
information, the Solar Radiation Components (DHI and DNI) have to be estimated
|
|
from the available measurements of GHI, zenith angles (Z) and datetime
|
|
information. \textcite{erbsEstimationDiffuseRadiation1982} present an empirical
|
|
relationship between GHI and the diffuse fraction DF and the ratio of GHI to
|
|
extraterrestrial irradiance $K_t$, known as the Erbs model. The DF is then used
|
|
to compute DHI and DNI as follows:
|
|
|
|
\begin{equation}
|
|
\begin{aligned}
|
|
\text{DHI} &= \text{DF} \times \text{GHI} \\
|
|
\text{DNI} &= \frac{\text{GHI} - \text{DHI}}{\cos{\text{Z}}}
|
|
\end{aligned}
|
|
\end{equation}
|
|
|
|
All the other parameters related to solar irradiance, such as the in-plane
|
|
irradiance components, in-plane diffuse irradiances from the sky and the ground
|
|
are computed using the Python pvlib.
|
|
|
|
The values that cannot be either calculated or approximated from the available
|
|
data, such as the precipitation, wind direction, incidence angles in place of
|
|
vertical and main/secondary surface axis have been replaced with the default
|
|
CARNOT placeholder value of -9999. The relative humidity, cloud index, pressure
|
|
and wind speed have been fixed to 50\%, 0.5, 96300 Pa, 0 $\text{m}/\text{s}$
|
|
respectively.
|
|
|
|
\subsubsection{\pdome\ and CARNOT model comparison}\label{sec:CARNOT_comparison}
|
|
|
|
With the WDB data compiled, we can now turn to simulating the CARNOT model and
|
|
compare its behaviour to that of the real \pdome\ building.
|
|
|
|
Unfortunately, one crucial piece of information is missing: the amount of heat
|
|
the HVAC either pumps in or takes out of the building at any point in time. This
|
|
value could be approximated from the information of electrical power consumption
|
|
and the EER, COP values given that it is known if the HVAC is in either heating
|
|
or cooling mode.
|
|
|
|
This information lacking in the existing experimental datasets, the heat
|
|
supplied/ taken out of the system has been inferred from the electrical energy
|
|
use, measured building temperature and HVAC temperature setpoint, with the
|
|
assumption that the HVAC is in cooling mode whenever the measurements are
|
|
higher than the setpoint temperature, and is in heating mode otherwise. As it
|
|
can already be seen in Figure~\ref{fig:Polydome_exp7_settemp}, this is a very
|
|
strong assumption, that is not necessarily always correct. It works well when
|
|
the measurements are very different from the sepoint, as is the case in the
|
|
first part of the experiment, but this assumption is false for the second part
|
|
of the experiment, where the sepoint temperature remains fixed and it is purely
|
|
the HVAC's job to regulate the temperature.
|
|
|
|
\begin{figure}[ht]
|
|
\centering
|
|
\includegraphics[width = \textwidth]{Plots/CARNOT_comparison_1.pdf}
|
|
\includegraphics[width = \textwidth]{Plots/CARNOT_comparison_2.pdf}
|
|
\caption{Measured vs CARNOT simulated temperature for the Experimental
|
|
Datasets}
|
|
\label{fig:CARNOT_simulation_validation}
|
|
\end{figure}
|
|
|
|
The results of the seven simulations are presented in
|
|
Figure~\ref{fig:CARNOT_simulation_validation}. Overall, the simulated
|
|
temperature has the same behaviour as the real \pdome\ measurements. A more
|
|
detailed inspection shows that for most of the experiments the simulated
|
|
temperature is much more volatile than the true measurements. This could be due
|
|
to an overestimated value of the Air Exchange Rate, underestimated amount of
|
|
furniture in the building, or, more probably, miscalculation of the HVAC's
|
|
heating/cooling mode. Of note is the large difference in behaviour for the
|
|
Experiments 5 and 6. In fact, for these experiments, the values for the
|
|
electical power consumption greatly differ in shape from the ones presented in
|
|
the other datasets, which could potentially mean erroneous measurements, or some
|
|
other underlying problem with the data.
|
|
|
|
Finally, it is possible to conclude that the CARNOT building behaves comparably
|
|
to the real \pdome\, even if not perfectly simulates its behaviour. These
|
|
differences could come from multiple factors, missing information that had to
|
|
be inferred and/or approximated, such as the Air Exchange Ratio, the heat
|
|
provided/extracted, the amount of furniture in the building, the overall shape
|
|
and size of the building, as well as possibly errors in the experimental data
|
|
used for validation. A more detailed analysis of the building parameters would
|
|
have to be done in order to find the reason and eliminate these discrepancies.
|
|
|
|
|
|
\clearpage
|