Sustainability is expressed as meeting present environmental, social, and economic needs without compromising these factors for future generations A practice cannot be said to be 'sustainable for X years/generations.' The use of any span of time disqualifies the activity. Sustainability is for perpetuity.
Sustainability also means greater efficiency in resource use, ultimately giving benefits to economic growth and overcoming poverty, as well as health and quality of life.
Sustainable design and sustainable development are critical factors to sustainable living. Sustainable design encompasses the development of appropriate technology, which is a staple of sustainable living practices. Sustainable development in turn is the use of these technologies in infrastructure. Sustainable architecture (see Green building) and agriculture are the most common examples of this practice.
Photovoltaic vaccine refrigeration at Centro De Salud
. This photovoltaic system was designed to power a DC Vaccine Refrigerator at the hospital Centro De Salud in Parras, Mexico. Centro De Salud had a list of items that needed to be purchased at their hospital. Among these was a new vaccine refrigerator. After learning of this, the project group members set out to design a PV system for the hospital that could fulfill this need.
PV systems are well suited for vaccine refrigeration for a few reasons. PV arrays are becoming an increasingly popular alternative to gas generators for supplying energy to off-grid vaccine refrigeration because of their ability to create reliable energy that requires little system maintenance. LINK PDF According to the World Health Organization, PV refrigeration systems are much more efficient at maintaining internal temperatures in refrigerators than gas generators. This creates for an overall greater reliability of the refrigerator system. In the case of Centro De Salud, having a PV powered vaccine refrigerator could prevent vaccine spoilage due to grid power outages, which can be very costly.
Micro filter dams at Pedregal, a Permaculture Demonstration Center in Oaxaca, Mexico.