Mitigation of the energy-water collision through integrated rooftop solar and water harvesting and use for cooling

Conservation policy is usually developed for regions that encompass only one environmental realm because of logistical, institutional and political constraints. This is inadequate because these realms often interact through processes that form, utilize and maintain interfaces or connections, which are essential for the persistence of some species and ecosystem functions. I present a conceptual framework for sustainable development that explicitly accounts for energy and water demand of the built environment offset by rooftop harvest opportunities. I wish to challenge you to think of PV solar and rainwater that can be captured on a roof and used in evaporative coolers and water-cooled vapour-compression air-conditioning as a substitute for water and electricity that would otherwise be drawn from networks. Rainwater cisterns are often overflowing without the recognition that they are full of refrigerant R718, containing 2.37 kW-hours of "coolth" per US Gallon which can be applied to improve the energy-efficiency of air-conditioning systems, and to mitigate urban heat islands by supporting vegetation and water-features. To this end I have developed a rainwater harvesting wizard http://gettanked.org/ coupled to estimate demand for irrigation, swimming pools and evaporative coolers. I am contemplating adding a complementary rooftop solar PV system sizing tool for climates where monsoonal conditions require vapour compression dehumidification. In the process I have been assisting in the informing Australian and New Zealand households of the relative efficiency of heat and cooling appliances that have emerged on the market. So I have prepared design data for 69 Australian and 18 New Zealand locations in collaboration with New Zealand's National Institute of Water and Atmospheric Research (NIWA) in updates of the climate data files used in Australian and New Zealand house energy rating schemes (HERS). Design data are normally distilled from meteorological records to represent design conditions that are exceeded only rarely, but can also be derived from representative meteorological year (TMY) files provided at the EnergyPlus website. ASHRAE’s (2013) analysis of World Meteorological Office database also informs the limits of evaporative cooling effectiveness, but the TMY files are essential to obtain bins of coincident parameters that measure the frosting of heat pumps. The design data are temperature, humidity and solar radiation coincident with extreme events. Design data are required for calculation of peak thermal demand of the built environment. These data are essential to the design of heating, ventilation and air conditioning (HVAC) systems and will be posted at http://suntank.org/ as they are developed