## 5 Conclusions  
This study is aimed to analyze the performance of low-cost evaporative cooling (EC) options for climatic conditions of Multan (Pakistan). The hot and dry summer of Multan demands an efficient air-conditioning (AC) system for poultry birds. In this regard, the EC systems can provide cost-effective and an environmentally-friendly solution. Therefore, three kinds of EC systems, i.e., direct EC (DEC), indirect EC (IEC), and Maisotsenko-cycle EC (MEC) are investigated for thermal comfort of poultry birds. Thermal comfort of poultry birds in each case of the EC systems was assessed in terms of temperature-humidity (_THI_) and temperature-humidity-velocity (_THVI_) indices. Heat production against age and weight of poultry birds was also investigated. Weight of poultry birds with growing age increases. Consequently, heat production is also increased. This increased value of heat production (_HP_) gives birth to heat stress for growing birds. Young birds with less weight can survive a slightly higher range of THI compared to older birds, which show immense signs of heat stress with increasing weight. At ambient temperature higher than or equal to the normal poultry body temperature, latent \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Months** & **Ambient Conditions** & **DEC** & **IEC** & **MEC** \\ \hline January & & & & \\ February & & & & \\ March & & & & \\ April & & & & \\ May & & & & \\ June & & & & \\ July & & & & \\ August & & & & \\ September & & & & \\ October & & & & \\ November & & & & \\ December & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Applicability/feasibility of the EC systems for the climatic conditions of Multan. The results are based on numerical values of THI. Figure 14: Psychometric representation of the performances of EC systems for the months of April to October. HP surpasses sensible HP, which causes suffocation due to an increased latent load in the ambient air. DEC, IEC, and MEC systems achieve the required thermal comfort sensation for poultry birds. However, the DEC system increases relative humidity up to such an extent that it causes suffocation for the birds. It is concluded that, in summer conditions (with \(T_{db}>40\)\({}^{\circ}\)C) when poultry birds attain harvest mass, their heat production results in a higher latent load into the ambient air. Since the EC systems also contribute latent load into the supply air, poultry birds face suffocation due to excessive humidity in the air, which can be controlled by developing hybrid combinations of VCAC-EC systems. Additionally, MEC coupled with a desiccant air-conditioning unit (M-DAC) could potentially achieve thermal comfort of poultry birds for all months across Pakistan. Conceptualization, H.M.U.R. and M.S. Methodology, H.M.U.R. and H.A. Software, H.M.U.R. and H.A. Validation, M.S. and T.M. Formal analysis, H.M.U.R., H.A., and K.S. Investigation, M.S. and T.M. Resources, M.S. and M.U. Data curation, H.M.U.R., H.A., K.S., and R.R.S. Writing--original draft preparation, H.M.U.R. Writing--review and editing, M.S., T.M., M.U., R.R.S., Y.Z., and R.A. Visualization, M.S., M.U., R.R.S., Y.Z., and R.A. Supervision, M.S. and T.M. Project administration, M.S. Funding acquisition, M.S. All authors have read and agreed to the published version of the manuscript. This research received no external funding. All this work is part of the Ph.D. research of [PERSON] (1 st Author). This research work has been carried out in the Department of Agricultural Engineering, Bahauddin Zakariya University, Multan-Pakistan. The Bahauddin Zakariya University, Multan-Pakistan under the Director Research/ORIC grant titled \"Development and performance evaluation of prototypes of direct and indirect evaporative cooling-based air-conditioning systems\", awarded to Principal Investigator [PERSON], funded this research. We acknowledge support for the Open Access fees by the Hamburg University of Technology (TUHH) in the funding programme Open Access Publishing. The authors declare no conflict of interest.