## 4 Energy and Environmental Evaluation of the System Retrofitting Variants
### Annual Consumption of Primary Energy
\begin{tabular}{l l} \hline \hline \(\eta_{EC}\) & - & efficiency of production and transmission of steam from the facility's CHP plant, i.e., 0.875, \\ \(\eta_{W}\) & - & efficiency of steam utilization in the facility, i.e., 0.96. \\ \hline \hline \end{tabular}   
The annual consumption of primary energy for the production of cooling energy, as calculated using the aforementioned procedure, is compared in Table 4, with Variant 0 being the system modernization variant based on compression water chillers. According to Table 4, the best variant of chilled water production system modernization in the pharmaceutical plant was Variant 2, in which the core production of cooling energy was performed by a 1.65 MW steam-powered dual-stage absorption water chiller. This variant allowed for a reduction in the consumption of primary energy of over 370 MWh/a (12.3%) compared to the basic variant. In the case of Variant 1, the main reason for its higher consumption of primary energy than in Variant 0 was the constant operation of the compression water chiller generating 1020 MWh of cooling energy--resulting in annual consumption of over 660 MWh/a of primary energy. Despite this, even this solution enabled a reduction in primary energy consumption of over 170 MWh/a (5.6%) compared to the basic variant. The consumption of primary energy in the system retrofitting variants based on absorption water chillers was strongly influenced by the electricity and steam co-generationratio in the CHP plant powering the pharmaceutical factory. Figure 7 illustrates this influence for a constant efficiency of energy supply from the CHP plant equal to 0.84. An increasing co-generation ratio for the CHP plant powering the pharmaceutical factory resulted in lowering the consumption of primary energy in variants of retrofitting the cooling energy supply system based on absorption water chillers. On the other hand, when this ratio dropped to e = 0.30, the variants became less attractive than the basic variant. The threshold values of the co-generation ratio for which the variants based on absorption water chillers displayed primary energy consumption at the level of the basic variant were e = 0.37 for Variant 1 and e = 0.34 for Variant 2. \begin{table}
\begin{tabular}{l c c c} \hline \hline
**Parameter** & **Variant 0** & **Variant 1** & **Variant 2** \\ \hline Annual cooling energy production for compression systems, in MWh/a & 4620.0 & 1020.0 & 0 \\ \hline Annual cooling energy production for absorption systems, in kWh/a & 0 & 3600.0 & 4620.0 \\ \hline SEER for compression chillers [-] & 3.85 & 3.85 & - \\ \hline SEER for absorption chillers [-] & - & 1.09 & 1.14 \\ \hline \(\eta_{TOT}\)-total efficiency—Welectricity [-] & 0.40 & 0.40 & - \\ \hline \(\eta_{TOT}\)-total efficiency—steam [-] & - & 0.84 & 0.84 \\ \hline \(E_{p}\)—annual consumption of primary energy in MWh/a & 3000.0 & 2829.0 & 2628.7 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Annual primary energy consumption related to chilled water production. Figure 7: The influence of the co-generation ratio on primary energy consumption in the analyzed, system.