Hourly and daily domestic hot water consumption in social housing dwellings: An analysis in apartment buildings in Southern Brazil

Solar water-heating systems have been widely implemented in Brazilian social housing buildings. Although these systems have been extensively explored regarding energy consumption, little is known about the water consumption. This article analyzes hot water consumption data from 154 social housing apartments in Southern Brazil. Hourly and daily consumption were analyzed regarding volume, profile and seasonal variations. The current system design was analyzed and compared to optimum configurations. The water-heating system only provides hot water for the shower, and the measurements presented refer to untempered hot water - before mixing with cold water to reach end-use temperature. Three peaks were found to occur during the day: in the morning, during lunch time and in the evening, which was the highest. In addition, seasonal ambient temperature and solar radiation showed significantly correlated to daily hot water consumption. Summer average per capita hot water consumption was lower than other seasons', while the average consumption during fall was the highest. If the collectors were installed facing North and with a 26 degrees inclination, the solar hot water system would provide more adequate temperatures.

Automated summary

This study analyzed hot water consumption data from 154 social housing apartments in Southern Brazil. The findings showed three peaks in hot water consumption during the day and significant correlations between consumption and seasonal ambient temperature and solar radiation.