PVT potential for a small-scale brewing process: A case study

Abstract

Reported cases of solar energy integration in industrial brewing processes are mostly found in medium-sized and large breweries. Given the brewing process's requirement for low-temperature heat and cold, a solar-assisted polygeneration system proves to be suitable. Microbreweries typically lack steam boilers, often relying on gas burners or electric resistors for heat supply. Additionally, small vapor-compression chillers are common for cold production. A hybrid photovoltaic-thermal (PVT) system has the potential to preheat brewing water and generate electricity. This study evaluates the energy output and economic viability of PV and PVT systems installed on a microbrewery's roof, utilizing actual heat and cold load profiles from a Spanish microbrewery. Energy yield calculations are based on simulations using TRNSYS. In a hot coastal Mediterranean location, the largest proposed PVT system could cover up to 26.4 % of electric consumption (self-consumption) and fulfill 47.6 % of the heat demand for water preheating. These figures decrease to 23.2 % (electricity) and 42.4 % (heat) for an inland temperate Mediterranean site, and to 27.6 % (electricity) and 35.7 % (heat) for a central European location. While the electric yield matches between a high-efficiency PV system and similar-sized PVT systems (difference between −1.3 % and −10 % for unglaze, and −5% to −15 % for glaze), the PVT's energy yield surpasses PV by up to 67 %, location and system size dependent, when considering useful heat. However, the PVT system is less economic-effective compared to PV, resulting in a payback period exceeding 12 years. Research and development efforts should focus on improving manufacturing techniques to reduce system costs.