Open Access Editorial Special Issue

Open Access Case study: Special Issue

A Case Study of Flow Regulators Installed in Washroom Taps within an Office Building

Steven R. Brown, Jonathan Chenoweth, Stuart Blofeld, Lorna Hamilton, Mindy Hadi

International Journal of Environment and Climate Change, Page 65-76
DOI: 10.9734/BJECC/2016/18184

Aim: To evaluate the operational performance of water efficiency products in order to report the actual-versus-potential impact on water demand.

Study Design: The study monitored the volume of water used from taps situated in two male and two female washrooms in an office building. During a 21 week period, the tap flow rates were decreased, without occupants being informed, and water usage was recorded and analysed.

Place and Duration of Study: The first floor of an office building located at the Building Research Establishment (BRE) site, in Garston near Watford, UK. The study took place from December 2012 to May 2013.

Methodology: Flow regulators were installed in-line with the taps to reduce the flow rate. Using flow meters and data loggers, the water usage was recorded and analysed.

Results: During the 21 week study, 6,217 events were recorded, where an event consisted of one or both taps being used in the same visit by a single user. The installation of the flow regulators failed to provide robust evidence that a reduction in water flow from taps equated to an increase in water efficiency. 

Conclusion: Evaluating the operational effectiveness of low cost water efficiency products is time consuming and expensive. The actual performance of flow regulators, which are low cost and simple to install, failed to achieve the expected gains in water efficiency.

Open Access Review Article: Special Issue

Examination of Domestic Cold Water Systems

Richard K. Beattie, Damien Kane

International Journal of Environment and Climate Change, Page 90-96
DOI: 10.9734/BJECC/2016/23726

The design of domestic cold water systems is inherently based upon the fixture unit or demand unit method. Therefore, it is fundamentally necessary to understand these water demand units and how to interpret them in order to design efficient water systems that enable a balance between capital cost (where oversizing leads to elevated capital cost) and engineering good practice. Recent sustainability initiatives aimed at reducing water usage encourage the uptake of devices such as flow limiters, spray and percussion taps and low flow appliances and have driven peak water demands down in buildings. Maintaining water movement within the cold water system prevents overheating and helps to maintain a healthy hygienic system. Stagnation exacerbates overheating and may contribute to contamination by micro-organisms. To promote movement of cold water within pipework systems there has been a recent move towards adopting strategies that were not traditionally incorporated into cold water pipework design such as, a secondary cold water return circuit and end of line solenoid flush (dump) valves. These are an added expense, contribute to wasted water or energy and should therefore be carefully considered when incorporating into domestic cold water systems taking cognisance of the other contributory factors such as the building water usage and turnover, building air tightness standards and sanitary ware specification. Also water conservation in buildings is another reason to have an appropriately sized system for the potential water consumption as older appliances had larger flow rates than present; this subsequently has a knock-on-effect on the buildings drainage pipework, system selections and sizing, for example WCs.

This paper presents an examination into the importance of sizing a cold water distribution system appropriately and the effect of modern building design standards on operational performance. Finally, through the experience of multiple engineers from many consultancies over several years, a summary of cold water services issues caused in modern buildings is presented and potential strategies to mitigate against excessive temperatures and promote water movement and turnover is given.

Open Access Original Research Article - Special Issue

Utilising Time of Use Surveys to Predict Domestic Hot Water Consumption and Heat Demand Profiles of Residential Building Stocks

Olivier Neu, Simeon Oxizidis, Damian Flynn, Donal Finn

International Journal of Environment and Climate Change, Page 77-89
DOI: 10.9734/BJECC/2016/18188

Aims: The prediction of water consumption patterns is a challenge, especially when water metering is not available at scale. The use of time-of-use survey (TUS) data offers an alternative to metering in order to track the general patterns of water consumption across large and representative groups of end-users. The paper focuses on the prediction of analytical domestic hot water (DHW) demand profiles for detailed building archetype models, using an occupant focused approach based on TUS data. The paper illustrates and discusses the resulting capability of dwelling archetypes to capture variations in heat demand and energy usage for water heating on a national scale and at high time resolution.

Methodology: Five dwelling types are considered over different construction periods, representative of the majority of the Irish residential stock, which is used here as a case study. They are modelled at room level using EnergyPlus and converted into archetype models. A bottom-up approach is utilised to develop the required operational data at high space and time resolution. That methodology applies Markov Chain Monte Carlo techniques to TUS activity data to develop activity-specific profiles for occupancy and domestic equipment electricity use. It is extended to DHW demand profiles by combining the probability distributions for particular TUS activities with average daily DHW consumptions, depending on the household size, day type and season.

Results: The archetype models capture variations in DHW consumption, heat demand and energy usage for DHW heating, on a national scale and a fifteen-minute basis. Moreover, they are found to be 90% accurate with the Irish standard dwelling energy assessment procedure in estimating the annual energy requirements for DHW heating.

Conclusion: This study demonstrates the potential for utilising time of use surveys to predict domestic water demand profiles on a national scale and at high time resolution.

Open Access Original Research Article - Special Issue

An Analysis of Domestic Water Consumption in Jaipur, India

Seyed M. K. Sadr, Fayyaz Ali Memon, Arpit Jain, Shilpa Gulati, Andrew P. Duncan, Wa’el Hussein, Dragan A. Savić, David Butler

International Journal of Environment and Climate Change, Page 97-115
DOI: 10.9734/BJECC/2016/23727

Aim: To explore the relation between water consumption and water use behaviour and attitudes, and devices applied in households in urban areas in India.

Methodology and Study Site: This paper presents the results of a domestic water consumption survey carried out in Jaipur, India. A questionnaire containing over 60 questions was developed to collect information on households’ characteristics (e.g. family size, household type, and number of children), indoor and outdoor water use activities and their respective frequencies and durations. Information was also gathered on the volume of water used in each of these activities. Over 90 households of different types (standalone houses and apartments in a university campus and Jaipur city) participated in the survey. The survey results were analysed using cluster analysis and one-way analysis of variance (ANOVA).

Results: The results show that the per capita consumption varies considerably with household type and size. The average water consumption was 183 and 215 litres/person/day for standalone households and apartments, respectively. Water used in bathing and WC's represent the highest proportion of water consumption in both stand-alone houses and apartments. Over 40% of the households reported no use of showers. The per capita water consumption is inversely related to family size especially in stand-alone houses.

Conclusion: The information pertaining to water use habits and the qualitative and quantitative analysis can be used as an input to a proposed domestic water efficiency tool (DoWET) which can generate optimal water efficient composite strategies keeping in view a range of sustainability indicators including water saving potential, cost and associated energy consumption of the water saving devices and fixtures available in India.

Open Access Original Research Article - Special Issue

Feasibility Study of Water Saving Measures in Higher Education Buildings: A Case Study of the University of Aveiro

A. Silva-Afonso, C. Pimentel-Rodrigues, I. Meireles, V. Sousa

International Journal of Environment and Climate Change, Page 116-127
DOI: 10.9734/BJECC/2016/23729

Aims: Evaluate the water savings potential and financial viability of water saving measures in in higher education buildings

Study Design: The study follows an observational approach to characterize the current performance of existing buildings in terms of water consumption and evaluate the potential for increasing water efficiency.

Place and Duration of Study: Buildings of the Chemistry, Civil Engineering, Communication and Arts, Environment and Planning, and Mathematics Departments and the Pedagogic Complex of the University of Aveiro, Portugal, between May 2013 and July 2014.

Methodology: Water efficiency audits complemented with limited monitoring and simulation of investment scenarios.

Results: The payback period of the investment required to implement the measures was found to be less than 7 months in all the cases, with average water savings potential of 28% and ranging from 9% up to 37%.

Conclusion: Water savings measures are attractive solutions for university buildings in Portugal, particularly the older ones, because of their environmental and financial performance and the low investment required.

Open Access Original Research Article - Special Issue

A Laboratory Study into a Novel, Retrofittable Rainwater Harvesting System

Peter Melville-Shreeve, Chris Horstman, Sarah Ward, Fayyaz Ali Memon, David Butler

International Journal of Environment and Climate Change, Page 128-137
DOI: 10.9734/BJECC/2016/23724

Aims: To establish the system characteristics of a novel rainwater harvesting system.

Study Design: A laboratory test rig was used to assess the selected technology.

Place and Duration of Study: University of Exeter, Centre for Water Systems between June 2014 and May 2015.

Methodology: Previous research has identified that systems should have: 1) reduced capital costs, 2) reduced operational costs and 3) increased ease of retrofitting. To investigate the system’s ability to address these requirements, two full-scale laboratory test rigs have been used to assess flow and power consumption characteristics under a range of installation scenarios.

Results: The system was identified to have a mean power consumption of 0.12kWh/m3 during a one hour pump test. Electrical costs were found to increase when the power consumption of the 11W control board was taken into account.

Conclusion: Subject to reduction of the standby power consumption of the controller, the novel RWH system assessed in this study has potential to provide non-potable water supplies to households in the UK at a lower power consumption rate than existing water supply systems identified in the literature.

Open Access Original Research Article - Special Issue

Monitoring Drainage Water Quality during Green Roof Irrigation Trials Using Synthetic Greywater

Matthew Smith, Katherine Hyde

International Journal of Environment and Climate Change, Page 138-148
DOI: 10.9734/BJECC/2016/18189

Aims: To evaluate the potential for substituting green roof mains water irrigation by irrigation using lightly loaded synthetic greywater.

Study Design: The planted green roof system was designed to be operated and tested within a glasshouse.

Place and Duration of Study: Schools of Engineering, and Plant Sciences, The University of Reading, for 28 days commencing 28th of May 2012.

Methodology: A trial was conducted for comparing two planting schemes using Sedum and Stachys Byzantina and a third unplanted control. The three sets of growing boxes were subdivided between substrate depths of 10 cm and 20 cm. By further subdivision, half of each set were watered using mains water, and half using a synthetic greywater. The soil composition and water quality of the drainage (filtrate) water were monitored. Statistical analysis of the results was conducted.

Results: Consistency was observed in influent pH and EC, in both mains and greywater samples. Influent Na concentrations were higher in the greywater samples due to detergent content. The Na mass balance calculations for all boxes showed that some Na mass was unaccounted for when comparing aggregated concentrations in influent, plant tissue and soil with the aggregated Na mass in filtrate, plant tissue and soil water. It was concluded that this was likely to be due to retained/ponded irrigation water in the boxes, difficulties in attaining homogenous box flushing and the underestimation of soil Na. The variation in substrate depth affected all results. The plants themselves seemed to have little significant influence on the measured parameters, with the exception of the accumulation of Na mass in plants irrigated with greywater.

Conclusion: No improvement was observed in the quality of the greywater following filtration through the soil matrix. For longer term watering using greywater, a choice of Na resistant species should be considered, although the Sedum species used in this trial showed no recorded adverse growth effects due to Na accumulation.

Open Access Original Research Article - Special Issue

How Does Your Garden Flow? The Impact of Domestic Front Gardens on Urban Flooding

D. A. Kelly

International Journal of Environment and Climate Change, Page 149-158
DOI: 10.9734/BJECC/2016/23728

Aims: To quantify rainwater runoff from domestic front gardens as a consequence of increased impervious surface area and climate change impacts, thus allowing the runoff contribution from both newly and previously covered front gardens to be assessed in terms of the overall urban flood burden.

Study Design: Numerical simulation of the runoff from a typical front garden in response to simulated rainfall events for four UK cities (Edinburgh, Manchester, London, and Exeter).

Methodology: A typical front garden was simulated with varying areas of impermeable surface area (0%, 10%, 25%, 50%, 75%, and 100%) to represent observed trends in garden paving.  Storm events representing current design and projected future rainfall intensities were applied to each of the four cities.  The resultant runoff volumes were then quantified. 

Results: Runoff is shown to be directly proportional to both the impermeable surface area and the rainfall intensity.  Areas of impermeable paving can generate substantial volumes of runoff during a storm event which can contribute to localized flooding or add to the urban flood burden. Increased rainfall intensities and frequencies due to climate change are likely to increase runoff further.

Conclusion: Domestic front gardens play a vital role in managing surface water runoff in towns and cities. Growing trends of paving over front gardens put this role in jeopardy, while increasing rainfall intensities due to climate change make this role increasingly important. The quantification   of domestic front garden runoff provides a mechanism for facilitating the protection, and enhancement, of this important asset in terms of water and urban flood management.