Domestic hot water usage (DHW) accounts for a significant share of energy consumption in different types of buildings. Achieving a detailed characterization of domestic hot water usage profiles is of great relevance, as this information will allow for a more reliable assessment of the energy efficiency of systems and buildings. A deeper knowledge of the features of demand profiles will allow for the design of innovative control strategies based on consumption patterns. In this study, the authors review recent works on hot water consumption profiles in different types of buildings and then synthesize available information for the accurate estimation of the energy consumption resulting from DHW use. Water draw-off consumption patterns specified in national and international technical standards are reviewed and influential parameters on water consumption are identified, including climatic conditions, seasonality, building type and socio-economic factors. State-of-the-art modelling tools for generating DHW usage profiles are summarised and new research lines are then proposed, taking into account the caveats in the current characterization and modelling of DHW consumption in buildings.

A review of domestic hot water consumption profiles for application in systems and buildings energy performance analysis

Characterisation of domestic hot water end-uses for integrated urban thermal energy assessment and optimisation

Water temperature is often monitored at water sources and treatment works; however, there is limited monitoring of the water temperature in the drinking water distribution system (DWDS), despite a known impact on physical, chemical and microbial reactions which impact water quality. A key parameter influencing drinking water temperature is soil temperature, which is influenced by the urban heat island effects. This paper provides critique and comprehensive summary of the current knowledge, policies and challenges regarding drinking water temperature research and presents the findings from a survey of international stakeholders. Knowledge gaps as well as challenges and opportunities for monitoring and research are identified. The conclusion of the study is that temperature in the DWDS is an emerging concern in various countries regardless of the water source and treatment, climate conditions, or network characteristics such as topology, pipe material or diameter. More research is needed, especially to determine (i) the effect of higher temperatures, (ii) a legislative limit on temperature and (iii) measures to comply with this limit.

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Drinking water temperature around the globe : understanding, policies, challenges and opportunities

Effects of aquifer thermal energy storage on groundwater quality and the consequences for drinking water production: a case study from the Netherlands

Residual Chlorine in the Extremities of the Drinking Water Distribution System: The Influence of Stochastic Water Demands

Modeling temperature in the drinking water distribution system

Existing Dutch guidelines for the design of the drinking water and hot water system of nonresidential buildings are based on outdated assumptions on peak water demand or on unfounded assumptions on hot water demand. They generally overestimate peak demand values required for the design of an efficient and reliable water system. Recently, a procedure was developed based on the end-use model SIMDEUM to derive design-demand-equations for peak demand values of both cold and hot water during various time steps for several types and sizes of non-residential buildings, viz. offices, hotels and nursing homes. In this paper, the design-demand-equations are validated with measurements of cold and hot water patterns on a per second base and with surveys. The good correlation between the simulated water demand patterns and the measured patterns indicates that the basis of the design-demand-equations, the SIMDEUM simulated standardised buildings, is solid. Surveys were held to investigate whether the construction of the standardised buildings based on the dominant variable corresponds with practice. Surveys show that it is difficult to find relationships to equip the standardised buildings with users and appliances. However, the validation proves that with a proper estimation of the number of users and appliances in only the dominant functional room of the standardised buildings, SIMDEUM renders a realistic cold and hot water diurnal demand pattern. Furthermore, the new design-demand-equations based on these standardised buildings give a better prediction of the measured peak values for cold water flow than the existing guidelines. Moreover, the new design-demand-equations can predict hot water use well. In this paper it is illustrated that the new design-demand-equations lead to reliable and improved designs of building installations and water heater capacity, resulting in more hygienic and economical installations.

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Non-residential water demand model validated with extensive measurements and surveys

Validation of Non-residential Cold and Hot Water Demand Model Assumptions

Little is known about the water demand of non-residential users. This complicates the design of outdoor and indoor water distributions systems. In general, it results in overdimensioned designs that potentially lead to water quality problems. Also in non-residential buildings, insufficient knowledge is available on hot water demand, complicating the choice of the proper type and capacity of the heater. For proper design of the drinking water distribution system outside as well as inside buildings, knowledge of the peak demand value is essential. Existing guidelines do generally overestimate peak demand and do not provide insight into hot water demand. Therefore, new design rules are desired that predict peak demand more accurately in order to obtain an economic, hygienic and microbiological reliable water system. In this paper, a procedure is developed to derive design rules to calculate peak demand values of both cold and hot water for different types of non-residential buildings of different sizes. The models are based on water demand patterns simulated by SIMDEUM, an end-use model to simulate residential and non-residential water demand patterns. The outcomes of the developed rules are compared with measured peak demand values and with existing design guidelines. The SIMDEUM based rules give a better prediction of the measured peak values for cold water flow than the existing guidelines and for several types of buildings. Therefore, they will lead to improved design of distribution network, of indoor plumbing and water heater capacity, resulting in more hygienic and economical installations. Due to the modular structure of SIMDEUM, it can be employed to construct all type of buildings, such as schools, sport complexes, restaurants, for which similar rules can be developed applying the presented procedure.

E.J. Pieterse-Quirijns

Papers

Modeling temperature in the drinking water distribution system

Non-residential water demand model validated with extensive measurements and surveys

Validation of Non-residential Cold and Hot Water Demand Model Assumptions

Modelling characteristic values for non-residential water demand

Validatie rekenregels voor waterverbruik woontorens