Hybrid Domestic Hot Water System Performance in Industrial Hall

The renewable and waste heat sources implemented for the preparation of domestic hot water (DHW) allow for energy conservation and environment protection along with resource savings and economic benefits. The solutions, including non-conventional sources, are especially demanded in large halls in which energy and water consumption are crucial for maintenance costs. In this article, energy analysis of a DHW preparation system for workers’ hygienic purposes in a industrial hall was performed. The DHW preparation system consisted of three sources: a flue gases heat exchanger as the waste heat source, solar collectors as the renewable heat source and a gas boiler as the conventional source. In the analysis, data of a variable-temperature supply of water and hourly water consumption data from the measurements in the industrial hall, located in Poland, were applied. The results for all of the 8760 h of one year were examined. The analysis outcomes show that implementation of non-conventional sources can supply 81.4% of energy needed for DHW preparation, avoiding a lot of running costs; just 18.6% of heat demand had to be obtained from a gas boiler. The analysis also confirms that the system may operate correctly when the appropriate device size is applied, along with a proper control strategy that avoids overheating water and uses alternative sources.