At the 15-acre, 428-unit Tanque Verde Apartments complex in Tucson, Ariz., the 3-decades-old hydronic heating and cooling system was found to be leaking underground. Tenants complained about a lack of controllability, while repair bills mounted. Making matters worse, equipment was outdated, bandaged, and in desperate need of replacement. Owner Scotia Group Management LLC’s longtime mechanical contractor, Tucson-based Oracle Control Systems Inc., designed new hydronic heating and cooling, solar-thermal domestic-hot-water, and modular building-automation systems and installed large photovoltaic arrays. To read the article and see additional photographs, click here.