# Passive Solar Solutions for Buildings: Criteria and Guidelines for a Synergistic Design
## 1 Introduction
The scope of this analysis is to determine the impact of the different passive solutions while varying some controllable variables: the paper reports the first results of the investigation, where the most relevant influencing variables, such as latitude, orientation, building use, and shape factors, have been considered. Not much research has analyzed the topic from a general point of view in order to develop guidelines for passive solar application mainly providing a more qualitative outcome, describing the affecting parameters and defining rules of thumbs for sizing and related possible expected solar savings [12]. Other investigations focused on a specific topic, e.g., orientation, analyzing the effects by a deep theoretical \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{\begin{tabular}{c} **Heating** \\ **Technology** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Fossil fuel-Based** \\ **Equipment** \\ \end{tabular} } & \begin{tabular}{c} **Conventional** \\ **Electric** \\ **Equipment** \\ \end{tabular} & \
\begin{tabular}{c} **Heat Pumps** \\ **District Heat** \\ **District Heat** \\ **Hydrogen-Based** \\ \end{tabular} &
\begin{tabular}{c} **Other** \\ **Renewables and** \\ **Hydrogen-Based** \\ \end{tabular} \\ \hline
2010 & 59.7\% & 21.1\% & 2.9\% & 8.3\% & 8\% \\
2012 & 57.9\% & 19.9\% & 3.3\% & 10.1\% & 8.8\% \\
2014 & 60.1\% & 18.5\% & 3.4\% & 10.2\% & 7.8\% \\
2016 & 57.9\% & 21.2\% & 3.9\% & 9.1\% & 7.9\% \\
2018 & 57.1\% & 20.6\% & 4.3\% & 9.4\% & 8.6\% \\ \hline \hline \end{tabular} (a)  
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{\begin{tabular}{c} **Year** \\ **Year** \\ \end{tabular} } & \
\begin{tabular}{c} **Constructions without building** \\ **energy code** \\ \end{tabular} &
\begin{tabular}{c} **Constructions with mandatory** \\ **building energy code** \\ \end{tabular} & **nZEBs** \\ \hline
2019 & 5150 & 3750 & 250 \\
2025 & 3300 & 3100 & 3350 \\
2030 & 250 & 5000 & 5250 \\ \hline \hline \end{tabular} (b)  
\end{table} 
Table 1: (a) Heating technology sales, (b) global building construction area by type of building code. background validated by measures and results from experimental activity [13]. The present paper follows a different approach as it intends to quantify the effects of passive solar strategies in terms of energy savings in different conditions: this will allow to determine the most suitable solutions in different cases and to define design guidelines according to the quantified impact of the variables analyzed. The influencing parameters work together in defining the performance of a passive solar strategy: heating and cooling must be provided according to the living patterns that depend on building use, but also orientation that determines room distribution. Climate is linked to latitude and affects the energy balance and operativity by determining sun hours and lighting levels. Cost depends on the integrability in building design, thus, on the kind of structure and building shape: integration of massive systems in heavyweight buildings, for example, would be relatively easy, but could represent a high cost for lightweight ones. As all these elements work in synergy, a synergy of different strategies may achieve a better result in terms of energy saving. Recent investigations on passive solar systems and design integration in buildings have generally focused on spot solutions, either through a set of parametric simulation to verify and optimize the contribution of the asset to the building [14], or to characterize, evaluate, and maximize the performance of a specific device in individual applications [15]. The present paper intends to evaluate the efficacy of the synergy of different passive strategies and quantify the impact on building energy demand. Both direct, indirect, and isolated solutions can be designed to minimize each other's side effects.