End Use Level Water and Energy Interactions: A Large Non-Residential Building Case Study

Water Benchmarking in Buildings: A Systematic Review on Methods and Benchmarks for Water Conservation

Water conservation is essential to sustainable development, and among human activities, buildings are responsible for a significant portion of total water consumption. Therefore, we present a systematic review that aims to search for valuable contributions from benchmarking and their potential significance to water conservation. The relevance of performing such a review is to support the research in the field, organise information, and highlight both the lack of data and valuable results in specific building types. Benchmarking highlights best performance buildings, while it also classifies performances, which allows developing interventions for different buildings. Seventy-two documents on the environmental performance of buildings were reviewed, and a variety of methods, metering procedures, and indicators were found as valuable data for water-saving initiatives. In addition to a systematic search in SCOPUS, searches were made in Science Direct and Google Scholar databases. Although the main challenge in this matter lies in the lack of procedures standardisation, it was found that performing benchmarking is relevant for accurately developing water conservation initiatives. Gains of over five million m3 per year in a set of buildings or above 151 thousand m3 per year in a single factory were found, which indicate the existing potential for water conservation.

Assessing the Impact of Water Efficiency Policies on Qatar’s Electricity and Water Sectors

Water and electricity have a unique relationship in the modern world as one requires the other in a complex system of networks to supply the utility to the customers. This energy–water interaction is especially peculiar in the Gulf Cooperation Council, where there are limited water resources, but extremely high use rates. Qatar provides a unique case in terms of extreme water scarcity and excessive water use. To understand the intricate network, this paper establishes an updated and comprehensive qualitative model of the water system in the country with the help of a water balance and system dynamics (causal loop diagram) methodology. Regression estimates are then used to estimate future water and energy consumption in addition to carbon dioxide emissions until the year 2050. Finally, system dynamics (stock and flow diagram) is used to determine the supply impacts of efficiency policies including limiting of groundwater abstraction to only 50 million m3, reduction of water consumption in the household, commercial and industrial sector by 10%, and gradual increase in the share of reverse osmosis (RO)-produced desalinated water to 50% in order to assess the supply volume, electricity consumption and CO2 emissions. The efficient use of water in different sectors of the economy results in a combined saving of 1222 GWh (8.1%) or 594,000 tons CO2. Furthermore, by moving to membrane-based desalination technology energy consumption and carbon dioxide emissions can be reduced by 3672 GWh (24.3%) and 1.8 million tons CO2, respectively. Further results suggest that while replacing groundwater with desalinated water can increase the energy consumption significantly, reuse of treated wastewater has almost the same footprint as groundwater, but can increase the resilience of the system considerably as groundwater abstraction levels are lowered to their renewal rates.

Assessing water, energy and emissions reduction from water conservation measures in buildings: a methodological approach

Water-energy nexus is a cornerstone in modern societies, with significant impacts at social, environmental, and economic levels. In addition to the issue of water scarcity that several regions of the world already face or are forecasted to face in the near future due to demand increase and availability reduction (e.g. pollution, climate changes), water consumption in buildings entails substantial energy consumption. In most cases, part of this energy is produced from non-renewable sources, encompassing greenhouse gas emissions. The present research effort presents a generic methodology to assess the cascade impact of water efficiency measures in buildings in terms of water, energy and emissions reduction. The methodology is applied to the Mediterranean climate zone context for two different types of non-residential buildings: university buildings and hotels, with very distinct water end use and consumption patterns. Lastly, are performed sensitivity analyses between the proposed methodology and simplified approaches. Is observed that assuming a linear relationship between flow rate and water consumption can lead to overestimations of up to 64% in water savings. Is also explored the relevance of the water consumption and energy mix seasonality typical of climates with marked dry and wet seasons, such as the Mediterranean region. The importance of the seasonality is discussed in terms of the time scale considered to apply the methodology, revealing that adopting a simplified (annual) approach, instead of the proposed approach, can lead to relative differences between - 62 and 233% in the presented case studies.

Water Supply and Energy in Residential Buildings: Potential Savings and Financial Profitability

This article examines the suitability of water supply installations in residential buildings for the pressure conditions of the main water network, and evaluates the energy saving possibilities associated with pumping water into homes. It assesses the situation and the options for renovation in a sample of 151 buildings in the city of Zaragoza (Spain), estimating the savings in electric power and the possible financial returns that could be obtained. The results show that in half the buildings, the installations are inadequate and lead to inefficient energy use, which could be avoided by renovation. However, they also show that in many cases, this type of retrofitting would not be profitable for the building owners, meaning that technically viable solutions may not necessarily be financially viable. To mitigate or avoid the energy inefficiency in question, the public sector could step in by informing and financing support for building owners and regulating in the areas of town planning and construction.