## 4 Material Considerations  
In the remaining of the study, we will consider only reactions involving temperatures below 150 \({}^{\circ}\)C which corresponds to a building application [1]. However, the ideas developed in the present paper can be straightforwardly adapted to other applications or other sorbates.  
The dehydration of cobalt(II) chloride-6-hydrate (CoCl2.6H2O) was investigated in [24]. The enthalpy of formation was calculated using thermodynamic values. The results show that one mole of water corresponds to a variation of the reaction enthalpy about 55.2 kJ mol\({}^{-1}\). It is worth mentioning that the latter value is very close to the enthalpy of vaporization of ice at 25 \({}^{\circ}\)C i.e., 52 kJ mol\({}^{-1}\). This conclusion is also validated by [25].  
Enthalpy of reaction given in the literature are summarized in Table 1. The enthalpy of reaction of one mole of water is only varying between 55.1 kJ mol\({}^{-1}\) and 67.8 kJ mol\({}^{-1}\). Of course, this value is close to the observations made in the literature and given above. This observation is the starting point of our demonstration concerning the maximum efficiency of a chemical sorption heat storage integrated in a building.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Hydrated Salt** & **Dehydrated Salt** & \(\Delta_{r}H\) & \(\Delta_{r}H/\
u\) & **Reference** \\  & & **[kj mol\({}^{-1}\)]** & **[kj mol\({}^{-1}\)]** & **Reference** \\ \hline MgSO\({}_{4}\)\(\cdot\) 6 H\({}_{2}\)O & MgSO\({}_{4}\)\(\cdot\) H\({}_{2}\)O & 275.7 & 55.1 & [26] \\ LiNO\({}_{3}\)\(\cdot\) 3 H\({}_{2}\)O & LiNO\({}_{3}\) & 165.8 & 55.3 & [27] \\ Al\({}_{2}\)(SO\({}_{4}\))\(\cdot\) 18 H\({}_{2}\)O & Al\({}_{2}\)(SO\({}_{4}\))\(\cdot\) 8 H\({}_{2}\)O & 554.5 & 55.4 & [27] \\ CaCl\({}_{2}\)\(\cdot\) 6 H\({}_{2}\)O & CaCl\({}_{2}\)\(\cdot\) H\({}_{2}\)O & 277.0 & 55.4 & [27] \\ CuSO\({}_{4}\)\(\cdot\) 5 H\({}_{2}\)O & CuSO\({}_{4}\)\(\cdot\) 3 H\({}_{2}\)O & 111.7 & 55.8 & [26] \\ SrCl\({}_{2}\)\(\cdot\) 6 H\({}_{2}\)O & SrCl\({}_{2}\) & 342.0 & 57.0 & [27] \\ LiSO\({}_{4}\)\(\cdot\) H\({}_{2}\)O & LiSO\({}_{4}\) & 57.2 & 57.2 & [26] \\ CuSO\({}_{4}\)\(\cdot\) 3 H\({}_{2}\)O & CuSO\({}_{4}\)\(\cdot\) H\({}_{2}\)O & 114.8 & 57.4 & [26] \\ La(NO\({}_{3}\))\(\cdot\) 6 H\({}_{2}\)O & La(NO\({}_{3}\))\(\cdot\) 1.5 H\({}_{2}\)O & 260.4 & 57.9 & [27] \\ MgCl\({}_{2}\)\(\cdot\) 6 H\({}_{2}\)O & MgCl\({}_{2}\)\(\cdot\) 4 H\({}_{2}\)O & 116.4 & 58.2 & [26] \\ LaCl\({}_{3}\)\(\cdot\) 7 H\({}_{2}\)O & LaCl\({}_{3}\)\(\cdot\) H\({}_{2}\)O & 355.5 & 59.3 & [27] \\ Na\({}_{2}\)S\({}_{2}\)O\(\cdot\) 5 H\({}_{2}\)O & Na\({}_{2}\)S\({}_{2}\)O\({}_{3}\) & 279.9 & 56.0 & [27] \\ MgSO\({}_{4}\)\(\cdot\) 7 H\({}_{2}\)O & MgSO\({}_{4}\)\(\cdot\) H\({}_{2}\)O & 335.7 & 56.0 & [27] \\ CaCl\({}_{2}\)\(\cdot\) 2 H\({}_{2}\)O & CaCl\({}_{2}\)\(\cdot\) 0.3 H\({}_{2}\)O & 101.0 & 59.4 & [28] \\ MgCl\({}_{2}\)\(\cdot\) 6 H\({}_{2}\)O & MgCl\({}_{2}\) & 361.2 & 60.2 & [29] \\ KOH\({}_{2}\)\(\cdot\) 2 H\({}_{2}\)O & KOH \({}_{1}\)\(\cdot\) 1.2 H\({}_{2}\)O & 48.2 & 60.3 & [27] \\ Zn(NO\({}_{3}\))\(\cdot\) 6 H\({}_{2}\)O & Zn(NO\({}_{3}\))\({}_{2}\) & 372.0 & 62.0 & [27] \\ Na\({}_{2}\)S\(\cdot\) 5 H\({}_{2}\)O & Na\({}_{2}\)S & 310.0 & 62.0 & [30] \\ CaBr\({}_{2}\)\(\cdot\) 6 H\({}_{2}\)O & CaBr\({}_{2}\)\(\cdot\) 0.3 H\({}_{2}\)O & 353.9 & 62.1 & [27] \\ LiCl \(\cdot\) H\({}_{2}\)O & LiCl & 62.2 & 62.2 & [27] \\ K\({}_{2}\)CO\({}_{3}\)\(\cdot\) 1.5 H\({}_{2}\)O & K\({}_{2}\)CO\({}_{3}\) & 95.5 & 63.7 & [27] \\ SrBr\({}_{2}\)\(\cdot\) 6 H\({}_{2}\)O & SrBr\({}_{2}\)\(\cdot\) H\({}_{2}\)O & 337.0 & 67.4 & [27] \\ MgCl\({}_{2}\)\(\cdot\) 4 H\({}_{2}\)O & MgCl\({}_{2}\)\(\cdot\) 2 H\({}_{2}\)O & 135.6 & 67.8 & [26] \\ \hline \hline \end{tabular}
\end{table}
Table 1: Measured enthalpy of reaction extracted from the literature.