Trigeneration provides an effective means of power, heat, and cold production on-site. A proper design and well-managed operation of such unit can bring in substantial savings in consumed primary energy as well as in the amount of greenhouse gases released to the atmosphere, compared to a separate production of all three media. The studied sub-MW sized trigeneration unit comprises an internal combustion engine combined with an absorption chiller and heat management system, delivering all three media to a nearby industrial facility. A mathematical model is developed based on available design and process data, allowing for profit function setup and subsequent sensitivity analysis of economic parameters. Lowered efficiency of summer operation is analyzed, and a suitable solution is proposed, with estimated total investment cost of 114,000 € and anticipated simple payback period less than 2 years. This study is supported by the Slovak Research and Development Agency under contract nos. APVV-18-0134 and APVV-19-0170, and by the Slovak Scientific Agency, grant no. VEGA 1/0511/21.