Use of solar energy directly for household needs (without converting into electricity) Student: Ophir Arad

using solar energy directly for household needs, limits the use of this energy in the forms of heat and light. moreover, it limits the options for energy storage in batteries, and actually limits energy storage at all, and therefore alowwing direct use of the energy only in daytime.

1. in this form, using solar energy to power electrical devices is impossible (many of the modern household devices and tools are electric powered).
2. storing the energy in the shape of heat is trickier then storing it in batteries, and lasts for much shorter times. it requires the use of pipes and oil/steam and bulky thermal storage unit. might be obsolete.
3. heat storage and direct usage might be dangerous and needed to be handled properly.
4. it isnt possible to store solar energy in the form of light.
5. using light directley ("straight from the sun") could be only at day time.
6. hydrogen formed by solar water splitting is not a well established technology yet.
7. using heat-consuming-aplliances on demend lacks the controllabilitity of electricity-cunsuming appliances. (you cant turn off a solar propelled heat source)

direct energy usage is limited to day times only. the number of applications that can be activated with heat or light energy alone is limited. If energy storage is possible, its limited to less common ways such as thermal storage which is short-termed (or hydrogen storage in the future).

therefore - ways to use appliances directly by heat/hot air/steam or light should be found to lower the electricity demand of the household. additionaly, it is desired to find ways to store heat efficiently (that could be used for at least more then a night) and compatible with as many household appliances as possible.

moreover, there must be a consideration in the scale of the wanted energy harvesting/using system and storing system as well as integrating the systems to household needs in several scales (a single home, a building, a neighborhood, a city, or a whole country). thats because different systems are more efficient/simple/cost effective in different scales.