The generation of domestic hot water load profiles in Swiss residential buildings through statistical predictions

Abstract

A long-term field study recording domestic hot water (DHW) consumption in households was used to tune a load profile generator. The methodology used in this load profile generator is also applicable to electric loads in distribution grids. Accurate DHW load profiles are essential to estimate the performance of renewable energy systems. One day and long-term randomly generated DHW profiles are useful for simulation, sizing and optimization of components in solar hot water installations such as storage tank, heat exchanger, collector area and additional heater. This work is also relevant to create standards for product testing and certification. DHW usage and draw off patterns are geographically dependent, so recent and local measurements are required to tune models and create accurate load profiles. Measurements show that DHW consumption is very volatile. The daily average value varies from 20 to 40 Litres per person (60 °C outlet temperature). The profiles underlie some trends (predominantly consumption in the morning or in the evening or spread over the day). The DHW consumption in Switzerland follows similar patterns observed in other countries, such as no significant decrease in 2 consumption during weekends, and no strong correlation with weather conditions neither outdoor temperature nor rain.

Analysis of centralized hot tap water systems calculation’s specifics

“…According to studies carried out [5,6,7], hot water consumption is similar in other Northern European countries, its values range from 20 l/day to 46 l/day [2]. In Finland hot water consumption is 43 l/day, but in Denmark -20 l/day [18,19].…”

Comfort of Domestic Water in Residential Buildings: Flow, Temperature and Energy in Draw-Off Points: Field Study in Two Danish Detached Houses

“…Santiago et al [19] conducted a full year monitoring campaign of domestic hot water in four dwellings in Switzerland. The measurements included two temperature sensors of supply and outlet water from the hot water tank and a flow meter measuring the accumulated water consumption with 0.25 L resolution.…”

Centralized hot tap water systems calculation’s specifics

“…According to studies carried out [23][24][25], hot water consumption is similar in other Northern European countries, its values range from 20 l/day to 46 l/day [26]. In Finland hot water consumption is 43 l/day, but in Denmark -20 l/day [27,28].…”