Circular economy (CE) as a new model of economic development promotes the maximum reuse/recycling of materials, goods and components in order to decrease waste generation to the largest possible extent. It aims to innovate the entire chain of production, consumption, distribution and recovery of materials and energy according to a cradle to cradle vision.

Naturally ventilated buildings have been worldwide increasingly welcomed, given the current global awareness toward environmental sustainability, indoor health-quality and renewable energy. As Natural Ventilation (NV) performance relies on building design and interaction with the local environment, its potential benefits are not always easy to take advantage of, and thus sets up a vital field of study. This paper provides an overview of investigations on the subject by collecting researches focused on thermal comfort, energy efficiency and indoor air quality.

Heat pumps are relatively simple appliances. They share similar components to refrigerators and air conditioners and effectively move an external source of heat to where it is needed, such as in buildings for heating or the production of hot water. Their key value is efficiency; for each unit of electricity consumed to operate them, they produce multiple units of usable heat. Because of this, they require much less energy input for a similar heating outcome compared to combustion technologies, making them naturally cleaner and generally cost effective to run.