The climate of Houston, classified as a humid subtropical climate with tropical influences, makes the heating, ventilation, and air conditioning (HVAC) systems the largest electricity consumers in buildings. HVAC systems in commercial buildings are usually operated by a centralized control system and/or an energy management system based on a fixed schedule and scheduled control of a zone setpoint, which is not appropriate for many buildings with changing occupancy rates. Lately, as part of energy efficiency analysis, attention has focused on collecting and analyzing smart meters and building-related data, as well as applying supervised learning techniques, to propose new strategies to operate HVAC systems and reduce energy consumption. On the other hand, unsupervised learning techniques have been used to study the consumption information and profile characterization of different buildings after cluster analysis is performed. This paper adopts a different approach by revealing the power of unsupervised learning to cluster data and unveiling hidden patterns. In this study, we also identify energy inefficiencies after exploring the cluster results of a single building’s HVAC consumption data and building usage data as part of the energy efficiency analysis. Time series analysis and the K-means clustering algorithm are successfully applied to identify new energy-saving opportunities in a highly efficient office building located in the Houston area (TX, USA). The paper uses 1-year data from a highly efficient Leadership in Energy and Environment Design (LEED)-, Energy Star-, and Net Zero-certified building, showing a potential energy savings of 6% using the K-means algorithm. The results show that clustering is instrumental in helping building managers identify potential additional energy savings.

Texas is experiencing tremendous growth, which puts pressure on resources including water and electricity supplies. Texas leads the nation in renewable energy production and is experiencing tremendous growth in the solar energy sector, with the Solar Energy Industries Association reporting that Texas is on track to become the fastest growing utility-scale solar market in the United States within the next five years. In this market, a new photovoltaic (PV) technology, floating solar, is gaining attention. Floating solar PV systems use the same types of PV panels as land-based systems, but the panels are either floating in the water (tethered to the land or substrate) or are suspended over a water body. Floating solar panels typically produce more energy than similarly-sized terrestrial systems (because of the cooling effect and reflectivity of the water). The shading provided by the solar panels can also significantly reduce evaporation and can improve water quality by inhibiting the growth of some types of algae and inhibiting bromide converting to bromate. In a climate where much of the state is arid or semi-arid and the entire state is subject to drought, a technology such as floating solar can be part of the solution. Texas reservoirs, water and wastewater treatment facilities, power plant cooling ponds, and irrigation ponds all have the opportunity to realize multiple benefits from floating solar that could not be achieved with a standard ground-mounted PV installation. Citation: Gamarra C, Ronk JJ. 2019. Floating solar: an emerging opportunity at the energy-water nexus. Texas Water Journal. 10(1):32-45. Available from: https://doi.org/10.21423/twj.v10i1.7050.