# Analytical Investigation of a Novel System for Combined Dew Point Cooling and Water Recovery
## 4 Discussion  
Based on the presented analysis, it is stated that the DPC-WR system is a promising technology to be applied in the wide range of climatic conditions, and therefore, it is an interesting alternative to other water recovery or combined cooling and water recovery techniques. To understand the difference with other techniques, the DPC-WR system is compared with the commercially available water recovery methods (Table 4), the recently researched methods for combined cooling and water recovery (Table 5), and the conventional cooling methods for air-conditioning appliance (Table 6). It can be seen that the DPC-WR system is characterized by the lowest electricity consumption among all water recovery methods (Table 4). Energy consumption of the DPC-WR system is low, even compared to thermal desalination methods such as MSF and MED, which are considered low energy-consuming. Compared to RO, the electricity consumption of the DPC-WR system is three times lower. Moreover, the operation of the DPC-WR system requires no external source of thermal energy, as most of the required energy is supplied with ambient air. Comparison with other combined cooling and water recovery methods may be somewhat difficult due to the different methods of calculating and interpreting the performance indicators. Nevertheless, there are some clear differences between the DPC-WR system and other combined cooling and water recovery methods. It can be noticed that the EUF of the DPC-WR system is higher than that of the HDH-VAR method [12] but lower than that of the HDH-VC method [15] (Table 5). However, it is important to notice that in [15], only \(\hat{W}_{net}\) was taken into account for EUF calculation, so if the same is assumed for the DPC-WR system, the average value of EUF would be 1386. As for the other performance indicators, the values of COP and GOR of the DPC-WR system are significantly greater \begin{table}
\begin{tabular}{l c c c c c} \hline \hline
**Cooling Method** & **DPC-WR** & **DPC** & **VMC** & **AB/AD** & **TEC** \\
**for Air-Conditioning Appliance** & & & & & \\ \hline Coefficient of Performance (COP) & 138–768 & \textgreater{}50 & 2–4 & 0.6–1.2 & 0.2–1.2 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: DPC-WR system comparison with other cooling methods for air-conditioning appliance [16; 18; 27]. \begin{table}
\begin{tabular}{l c c c c} \hline \hline
**Water Recovery Method** & **DPC-WR** & **RO** & **MSF** & **MED** \\ \hline Electric energy consumption, kWh/m\({}^{3}\) & 0.5–2.0 & 4–6 & 2.5–5 & 2–2.5 \\ Heat source required & no & no & yes & yes \\ Thermal energy consumption, kWh/m\({}^{3}\) & none & none & 15.8–23.5 & 12.2–19.1 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: DPC-WR system comparison with other water recovery methods [5]. \begin{table}
\begin{tabular}{l c c c c} \hline \hline
**Combined Cooling** & **DPC-WR** & **HDH-VAR** & **HDH-AD** & **HDH-VC** & **IEC-HDH** \\
**and Water Recovery Method** & & [12] & [13] & [15] & [19] \\ \hline Energy Utilization Factor (EUF) & 0.76–0.96 & 0.58 & N/A & 8.27 & N/A \\ Coefficient of Performance (COP) & 138–768 & N/A & \textgreater{}0.45 & 2.16 & 2.1–2.5 \\ Gained Output Ratio (GOR) & 354–1814 & N/A & \textgreater{}7.6 & 6.11 & 1.6–2.5 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: DPC-WR system comparison with other combined cooling and water recovery methods. than for any other methods. As it was discussed earlier, such high values of COP and GOR result from the fact that the only external source of energy supplied to the DPC-WR system is electric energy input to the fan. This operating principle is the biggest advantage of the DPC-WR system over other combined cooling and water recovery methods. Dew point cooling is proven a highly energy-efficient cooling method for air-conditioning appliance. Due to its low net energy consumption, dew point cooling is characterized by high COP value, which is significantly higher than for other conventional cooling methods [16,18,27].