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

Abstract

There is very little knowledge on the occupant actual hot water comfort (temperature and flow), usage practice, and routines (temporal and spatial distribution of hot water usage in a household). This paper describes the results from the total and hot water measurements in two Danish detached houses. The results show that, at the draw-off points, the temperature of 55 °C is never asked by the occupants, not even in the kitchen sink. The domestic water temperature differentiates depending on the function of the draw-off point, with the shower and kitchen taps being most energy- and water-intense. They constitute around 90% of the hot water use in the house. Shower units on average demand for highest temperature (i.e., 35.5 °C to 40.4 °C). Hand washing operates, on average, at temperature between 20.5 °C to 26.5 °C. Average water temperature at the taps located in utility room varies between 23 °C to 26 °C. These in-depth insight in the total and hot water use in two new-built low energy houses, can a) help building professionals designing more efficient hot water installations; b) enhance the research work on energy flexibility buildings by providing knowledge on most energy-intensive draw-off points; and c) facilitate district heating professionals in improving the network performance.

Peak Power of Heat Source for Domestic Hot Water Preparation (DHW) for Residential Estate in Poland as a Representative Case Study for the Climate of Central Europe

“…It is possible to discuss the value of the hot water temperature that should be used in the calculations. The results of studies of two single-family houses in Denmark [62] showed that the temperature of the water used in the shower was 35.5 • C to 40.4 • C, and for hand washing 20.5 • C to 26.5 • C. Taking the bath as a representative device and assuming the hot water temperature of 40 • C seems to be justified in the context of the quoted research results.…”

A Parametric Analysis for Short-Term Residential Electrification with Electric Water Tanks. The Case of Spain

“…For instantaneous water heating technologies, discomfort is assumed to be always zero. In this study a more restrictive approach than in [82] was used.…”

Who Produces the Peaks? Household Variation in Peak Energy Demand for Space Heating and Domestic Hot Water

“…This may impair the stability and reliability of energy grids. The metered heat data reflect practices related to space heating, such as heating and comfort practices [19,20], as well as DHW usage, such as showering and personal hygiene [18], where the shower and kitchen taps are found to constitute around 90% of the total DHW usage [21]. Thus, the data result from a complex interaction between occupants, building physics, and heating systems, particularly the components responsible for the indoor temperature adjustment and the use of DHW (see Figure 1).…”

“…Thus, the data result from a complex interaction between occupants, building physics, and heating systems, particularly the components responsible for the indoor temperature adjustment and the use of DHW (see Figure 1). One should note that the share of DHW and space heating in the total building heat demand varies significantly from buildings to buildings, depending on the occupants' habits and the energy performance of the building envelope [14,16,21].…”