Building Water Use Research Articles

Towards Reducing the Consumption of Drinking Water in Buildings as Part of the Circular Economy Model: Strengths–Weaknesses–Opportunities–Threats Analysis and Perspectives for Implementation

Progressive climate changes, drought resulting from them and the prospect of problems with access to water for people in cities mean that actions are being taken to minimize water use in buildings and to implement a circular economy in the water and wastewater sector. Within the water circular economy model, there is also a stage of “water consumption”. Minimizing water use in buildings undoubtedly has a number of advantages. However, it should be borne in mind that it may also have weaknesses, and if implemented on a large scale, it may be associated with certain threats. For these reasons, the aim of this paper is to critically analyze the possible directions of water management in buildings in order to reduce water consumption and increase the efficiency of its use. As part of the introduction, the model “towards a water circular economy for households” is presented and the possibilities of minimizing water consumption in buildings are discussed. The prospects for reducing the consumption of tap water are discussed in terms of existing opportunities, but also threats, barriers and limitations. A SWOT analysis of the implementation of drinking-water consumption reduction in cities is presented. The challenges faced by engineers, constructors, policy makers and consumers, and the potentialities for the development of this stage of the water life cycle, are considered. The conclusions summarize the current state and perspectives of water management in buildings. Based on the conducted analysis, suggested directions of activities for cities of the future in the technical, technological as well as socio-economic fields are indicated. There should be broad-based education, and efforts should be made to change the approach to designing and developing new guidelines. The implementation of minimizing water consumption should be accompanied by the control of possible negative effects and actions to mitigate them. In the transformation towards clean and available energy, future success should be seen in minimizing the consumption of drinking water in buildings.

A comprehensive review of air conditioning condensate water supply models

Non-potable water building systems have the potential to significantly reduce water consumption, aiding in the preservation of water resources used in urban supply. Among the alternative sources of non-potable water use in buildings, clear waters stand out due to their considerable quality. Condensate water from air conditioning is a kind of clear water that is typically discarded into the sewage. Little is known about the applicability of building systems for using condensate water from air conditioning in buildings - especially within the Brazilian context. To assess the potential for reducing potable water consumption and consequently evaluate the feasibility of implementing air conditioning condensate recovery systems, it is crucial to determine the quantity of available air conditioning condensate. Therefore, this work aims to identify, through a systematic review, the models for predicting the supply of condensed water in air conditioning systems and analyze methods and variables adopted to investigate their applicability within the Brazilian climate context.

Investigating water safety in multi-purpose buildings used as an elementary school and plumbing remediation effectiveness

Three buildings that were repurposed for use as an elementary school were shutdown for three months in response to the pandemic. Building cold and hot water quality was monitored before reopening to detect and resolve chemical and microbiological problems. The authors collected first draw pre-flush and post-flush water samples. First draw water samples did not contain detectable disinfectant residual, but nickel and lead sometimes exceeded the health-based action limits for cold water (max. 144 μg Ni/L, 3.4 μg Pb/L). Stagnant cold water at a bathroom sink (188 MPN/100 mL) and drinking water fountain (141.6 MPN/100 mL), in the same building, exceeded theL.pneumophilathresholds advised by the World Health Organization (WHO) (10 CFU/mL) and American Industrial Hygiene Association (AIHA) (100 CFU/mL). Fixture flushing was conducted to remove cold and hot stagnant water and noL.pneumophilawas detected immediately after flushing. Two weeks after no subsequent building water use, chemical and microbiological contaminant levels were found to be similar to levels prior to flushing with one exception. The maximumL.pneumophilalevel (kitchen sink, hot water: 61.1 MPN/100 mL) was found in a different building than the prior maximum detections. No repeat positive locations forL.pneumophilawere found during the second visit, but new fixtures were positive the organism. When this study was conducted no evidence-based guidelines for plumbing recommissioning were available. A single plumbing flush reduced heavy metal andL.pneumophilalevels below WHO and AIHA thresholds in all three buildings. Additional work is needed to examine the role of building size, type and plumbing design on fixture water quality in shutdown buildings.

Reclaimed water systems in office buildings: Perceptions of building facilities managers

AbstractBy the year 2050, 67% of the global population will be living in cities where water demand is projected to outstrip supply. This shortage calls for identifying ways through which urban residents and commercial interests can adapt to water stress. As commercial buildings contribute significantly to water consumption in cities, building facilities managers (BFMs) have a significant role in formulation and implementation of the adaptation approaches. Their perceptions of alternative water sources, including reclaimed water, are, therefore, important. In this study, the perceptions of 40 BFMs on reclaimed water use in buildings were analyzed using Q‐methodology. Analysis correlated the responses of different people, factoring out the groups of people who hold similar viewpoints. Results showed that participants could be categorized under four factors. Participants in Factor 1 perceived reclaimed water as being healthy and a worthy investment. Those in Factor 2, however, had negative perceptions and did not trust local governments to appropriately manage the treatment process, thus presenting health concerns. They also found reclaimed water repulsive. Participants in Factor 3 were also less willing to adopt reclaimed water, but felt that its use for non‐potable purposes would be acceptable. The final group, those in Factor 4 focused more on the cost efficiency and sustainability of reclaimed water, finding it acceptable on those grounds. However, they thought that decisions on its use should be the building owners' prerogative rather than the BFMs. The implications of these findings with respect to encouraging reclaimed water use in commercial office buildings are discussed.

Risk-based treatment targets for onsite non-potable water systems using new pathogen data.

Using local sources (roof runoff, stormwater, graywater, and onsite wastewater) to meet non-potable water demands can minimize potable water use in buildings and increase supply reliability. In 2017, an Independent Advisory Panel developed a risk-based framework to identify pathogen log reduction targets (LRTs) for onsite non-potable water systems (ONWSs). Subsequently, California's legislature mandated the development and adoption of regulations-including risk-based LRTs-for use in multifamily residential, commercial, and mixed-use buildings. A California Expert Panel was convened in 2021 to (1) update the LRT requirements using new, quantitative pathogen data and (2) propose treatment trains capable of meeting the updated LRTs. This paper presents the updated risk-based LRTs for multiple pathogens (viruses, protozoa, and bacteria) and an expanded set of end-uses including toilet flushing, clothes washing, irrigation, dust and fire suppression, car washing, and decorative fountains. The updated 95th percentile LRTs required for each source water, pathogen, and end-use were typically within 1-log10 of the 2017 LRTs regardless of the approach used to estimate pathogen concentrations. LRT requirements decreased with influent pathogen concentrations from wastewater to graywater to stormwater to roof runoff. Cost and footprint estimates provide details on the capital, operations and maintenance, and siting requirements for ONWS implementation.

New developments in premise plumbing: Integrative hydraulic and water quality modeling

AbstractSignificant seasonal changes in chemical and microbiological water quality can occur in buildings at different fixture locations due to temperature and time dependent reaction rates. Here, a series of calibrated plumbing hydraulic‐water quality models were developed for the extensively monitored Retrofitted Net‐zero Energy, Water & Waste (ReNEWW) house in West Lafayette, Indiana, USA. The eight new models predict the absolute level of free chlorine, total trihalomethanes, copper, iron, lead, NO3− (nitrate‐nitrogen), heterotrophic plate count (HPC), and Legionella spp. concentration at each fixture for plumbing use, operational characteristics, and design layouts of the plumbing system. Model development revealed that the carrying capacity to describe Legionella spp. growth (and other organisms) under water usage and plumbing design conditions is lacking in the literature. Reducing simulated building water use by 25% prompted increased absolute concentrations of HPC and Legionella spp., each increasing by a factor of about 105. When the simulated service line length was increased, Legionella spp. concentrations increased by up to 106 gene copies /L in the Summer season. The proposed modeling framework can be used to support better planning, design, analysis, and operational decision‐making.

Water Consumption and Environmental Impact of Multifamily Residential Buildings: A Life Cycle Assessment Study

Water use in buildings accounts for a large share in global freshwater consumption where research on the impacts of life cycle water use receive little or no attention. Moreover, there is very limited knowledge regarding such impacts that focus on the life cycle emissions from water consumption in building environments in the world’s most water-stressed countries. Hence, this study attempted to quantify the environmental impacts of operational water use in a multi-family residential building through a life cycle assessment (LCA). A small part of a Middle Eastern country, Doha (Qatar), has been selected for the primary assessment, while water-use impact in Miami (Florida) was chosen as a second case study, as both locations fall into similar climate zone according to ASHRAE Climate Zone Map. The LCA score indicated much higher impacts in the Doha case study compared to Miami. The variation in the result is mainly attributed to the raw water treatment stage in Doha, which involves energy-intensive thermal desalination. Again, relative comparison of the annual water and electricity use impacts for the modeled building was performed at the final stage for both locations. Water use was attributable for 18% of the environmental impacts in Miami, while this value increased to 35% in Doha. This initial assembled LCA result will be beneficial to both water authorities and building research communities in establishing more sustainable water use policies for specific regions/countries that will ultimately benefit the overall building environment.

Evaluating the performance of a decentralized graywater treatment system in a living building at Hampshire College, Amherst, MA, USA.

Decentralized graywater treatment systems are growing in popularity as the threat of water scarcity rises and wastewater's potential as a resource is recognized. In 2016, Hampshire College in Amherst, Massachusetts, completed construction of the R.W. Kern Center, a Living Building that incorporates physical filters and two constructed wetlands to treat graywater produced on-site. Grab samples of graywater were collected from four sites between August 2016 and March 2019. This study characterizes mixed graywater from all the building's fixtures and graywater from a coffee bar. Untreated mixed graywater was observed with median concentrations of 180mg/L for total suspended solids (TSS), 190mg/L for biochemical oxygen demand (BOD5 ), and 15mg/L for total nitrogen (TN), primarily in the form of total Kjeldahl nitrogen (TKN). Concentrations of TSS, BOD5 , and TN were reduced by 92%, 96%, and 73%, respectively, by the Kern Center's treatment system. Preliminary data from coffee bar effluent establish a wide range of high-strength graywater quality. Because Living Buildings by design explore the connections between people and their builtenvironments, this study also found that the behaviors of building occupants, particularly the café staff, had a direct impact on the functioning of the Kern Center's decentralizedgraywater treatment system. PRACTITIONER POINTS: On-site decentralized graywater treatment systems paired with waterless composting toilets are effective in reducing a building's water use and inmeeting net-zero water goals. Constructed wetlands can effectively treat graywater produced in acentral campus building with public spaces, office spaces, and a coffee bar. On-site decentralizedgraywater treatment systems require cooperation from bothbuilding occupants and water operators in order to function properly.

Alternative water sources in New Zealand's commercial buildings

Abstract Rainwater harvesting and greywater recycling are two potential measures to make significant reductions in commercial building water use in New Zealand. Rainwater harvesting involves the collection of water from roofs during rainfall events, while greywater recycling is the reuse of water from hand basins and showers for use in toilets and urinals. The feasibility of these systems was investigated via three areas of focus: drivers and barriers; system operation; savings to the water network. Initial results show volumetric wastewater tariffs are primary drivers for water efficiency and conservation. However, a lack of consistent regulation, perceived risks of water quality issues and loss of space for storage are perceived as barriers. Case-study buildings showed that, in locations where both water and wastewater are charged volumetrically, the relative benefit–cost comparisons were judged as acceptable by building management. Where only water is charged volumetrically (with wastewater based on annual rating valuations), this was less favourable. Water quality tests showed only minimal imperfections. Concerns appear to be largely an issue of perceived risk rather than actual risk. Together with site visits, the water quality testing has contextualised valuable feasibility, design and operational opportunities. The savings to the water networks, however, appear to be minimal.

Modeling the determinants of large-scale building water use: Implications for data-driven urban sustainability policy

As the world's population continues to urbanize, cities are struggling to meet the demand for key resources such as clean water. In urban areas, enhancing the sustainability and water efficiency of buildings is crucial to meeting the resource needs of a growing population. Nevertheless, the understanding of the determinants of urban water consumption – and specifically of multi-family residential buildings that constitute the bulk of the urban building stock – is limited. Using an extensive database of actual water use from New York City's Local Law 84, coupled with land use and demographic data from the NYC Primary Land Use Tax Lot Output (PLUTO) database and Census data, we apply weighted robust regression and geographically weighted regression (GWR) models to analyze the determinants and spatial patterns of water consumption in over 2300 multi-family buildings located in New York City. Our results indicate that occupancy, building size, building age, ownership structure, neighborhood demographic and socioeconomic characteristics, and the energy use intensity (EUI) of a building all have statistically significant effects on the water use intensity (WUI) of multi-family housing. Results of the GWR spatial analysis demonstrate large spatial variability across building characteristics, demographic variables and household income. The analysis and findings presented here give further support to the potential of targeted measures and incentives, segmented and classified by building characteristics and neighborhoods, to be effective tools for policymakers seeking to increase water efficiency in urban buildings and to accelerate reductions in resource use at the city scale.

A comprehensive life cycle water analysis framework for residential buildings

Most studies on the environmental performance of buildings focus on energy demand and associated greenhouse gas emissions. They often neglect to consider the range of other resource demands and environmental impacts associated with buildings, including water. Studies that assess water use in buildings typically consider only operational water, which excludes the embodied water in building materials or the water associated with the mobility of building occupants. A new framework is presented that quantifies water requirements at the building scale (i.e. the embodied and operational water of the building as well as its maintenance and refurbishment) and at the city scale (i.e. the embodied water of nearby infrastructures such as roads, gas distribution and others) and the transport-related indirect water use of building occupants. A case study house located in Melbourne, Australia, is analysed using the new framework. The results show that each of the embodied, operational and transport requirements is nearly equally important. By integrating these three water requirements, the developed framework provides architects, building designers, planners and decision-makers with a powerful means to understand and effectively reduce the overall water use and associated environmental impacts of residential buildings.

자동 기상관측 자료를 이용한 건축물 에너지 분석

EnergyPlus is a whole building energy simulation program that engineers, architects, and researchers use to model energy and water use in buildings. Modeling the performance of a building with EnergyPlus enables building professionals to optimize the building design to use less energy and water. This program provides energy analysis of building and needs weather data for simulation. Weather data is available for over 2,000 locations in a file format that can be read by EnergyPlus. However, only five locations are avaliable in Korea. This study intends to use AWS data for having high spatial resolution to simulate building energy. The result of this study shows the possibility of using AWS data for energy simulation of building.

Development and application of weather-normalized monthly building water use model

This study proposes a new monthly whole-building water use regression model for weather-normalized water performance evaluation: a combination three-parameter multi-variable regression (3-P MVR) cooling model using outdoor temperature in a change-point model and precipitation amount/occurrence as an additional independent variable. To select appropriate weather variables influencing a building's water use, previous studies on the water use models at the municipal level were reviewed. The selected weather variables were then tested using the multi-year monthly water use data collected from the two separate water meters (i.e., the main building meter for indoor water use; and sprinkler meter for landscape water use) of the case-study office building in central TX. The proposed water use model is based on twelve monthly, building-level water use data, which should be available for most buildings that are supplied water from a municipal provider. This model allows a year-to-year, weather-normalized comparison for self-referencing as well as savings calculations from various water conservation measures. This new method will reduce uncertainty about reported water savings from water conservation measures applied and improve the credibility of water conservation programs.

Green Building Water Use Problems and Development

The utilization and disposal of water rationalization can be said as a building is one of the criteria of green building, water reuse technology can reduce wastewater directly discharged pollution of the environment and resource consumption, so our water reuse technology, even said that all aspects of the development of green building have a lot of prospects. Although the front is difficult, but the future development prospects are bright.

Experimental study of the phase change and energy characteristics inside a cylindrical latent heat energy storage system: Part 1 consecutive charging and discharging

Solar domestic hot water (SDHW) systems are a cost effective and efficient way to pre-heat domestic water for hot water use in buildings. Currently used sensible energy storage systems (commonly using water as the storage medium) are simple and inexpensive, but require large amounts of storage material, and therefore are heavy and take up considerable space. Latent heat energy storage systems (LHESS) store the energy absorbed/released when a material goes through a phase transition: these materials are called phase change materials (PCMs). Because of the large quantities of energy that are stored during a phase change, latent heat energy storage is more dense than sensible energy storage, and can therefore reduce the weight and space requirements of the energy storage system. The main objective of this research is to study the heat transfer processes and phase change behavior of a PCM during consecutive charging and discharging of a LHESS. This leads to better understanding of the melting and solidification processes in order to optimize future LHESS design.In part 1 of this paper the design of a LHESS that can operate under both consecutive and simultaneous charging and discharging modes is introduced. Dodecanoic acid is used as the PCM, as it has been shown to be safe, relatively inexpensive, and has a melting temperature in a range suitable for use with SDHW. Experimental results of consecutively charging and discharging the system are presented and the effect of the heat transfer fluid flow rate is explored. It was found that during charging a faster flow rate leads to shorter melting times; however, during discharging, the flow rate does not affect the rate of solidification.

Water sustainable management for buildings

This paper presents a literature review article that deals with how to manage water in build­ings, specifically in facility projects, in ways to save water during the use, maintenance and operation of the building. This work is aimed at architects, builders and developers, and may be helpful for decision-making in the planning and management of efficient water use in buildings.

A GIS Methodology for Estimating the Carbon Footprint in Municipal Water and Wastewater in Fairfax County, Virginia

ABSTRACT The carbon footprint metric is a useful tool for predicting the impact of a building or process on the environment. Many industries are developing models that perform the life cycle assessment of the carbon footprint based on energy consumption. These models typically do not consider the embodied energy associated with the treatment and distribution of water to and from the facility. A tool was developed for use by Fairfax County, VA, planners that estimates the tons per year of carbon dioxide equivalent for commercial, industrial, and residential building water use. This estimate includes the embodied energy requirements needed to collect, treat, and distribute water and wastewater. This model can be used by planners to evaluate the environmental impact of proposed and existing facilities. The estimation of energy consumption and subsequent carbon footprint calculation relies not only on the quantity of water distributed but also on the geography of the distribution and collection network. Distance from the plants and elevation were shown to play a significant role in the determination of the energy consumption.[1] A geographical information system (GIS) was developed (using ArcGIS Desktop Version 9.2) for Fairfax County that converts the annual water and wastewater needs for a facility into tons of CO2 per year. This tool answers critical questions related to the impact of demand-side sustainable water practices on the comprehensive carbon footprint. In April 2007, the American Society of Heating Refrigerating and Air-Conditioning Engineers (ASHRAE) held a workshop in Washington, DC, on forecasting carbon emissions from buildings. An important result of this workshop was the identification of future research needs, which included “embodied energy and emissions associated with water use in the building.” This would be highly site-specific, depending on characteristics of the local water supply and treatment system. (ASHRAE Workshop Report, 2007.) This work begins to address the need identified by ASHRAE in investigating the carbon footprint of the embodied energy in municipal water and wastewater.