In passive solar building design, windows, walls, and floors are made to collect, store, reflect, and distribute solar energy, in the form of heat in the winter and reject solar heat in the summer. This is called passive solar design because, unlike active solar heating systems, it does not involve the use of mechanical and. Passive solar technologies use without active mechanical systems (as contrasted to active solar, which uses ). Such technologies convert sunlight into. The ability to achieve these goals simultaneously is fundamentally dependent on the seasonal variations in the sun's path throughout the day.This occurs as a result of the of the Earth's axis of rotation in relation to its. The •,, and (sunshine)• Seasonal variations in solar gain e.g. cooling or Technically, PSH is highly efficient. Direct-gain systems can utilize (i.e. convert into "useful" heat) 65–70% of the energy of solar radiation that strikes the aperture or collector. The basis for passive solar building design has been developed from a combination of, Personal is a function of personal health factors (medical, psychological, sociological and situational), ambient air temperature,, air movement (, ) and (affecting. • Placement of room-types, internal doors and walls, and equipment in the house.• Orienting the building to face the equator (or a few degrees to the.