Direct Gain << a room receiving sunlight directly through a window area >>
- As the sunlight strikes surfaces and objects the heat energy is released. Orienting the appropriate amount of windows on the south side (if living in the northern hemisphere) will bring winter sunlight into the space, generating heat. Reducing the window areas on the other orientations will both reduce winter heat loss and prevent summer overheating.
Indirect Gain << a room receiving solar heat within its confines and having obtained that energy without receiving the sunlight directly >>
- With indirect gain applications, south windows or other forms of solar collectors generate heat from the sun, then tranfer this heat through the air or other materials to rooms without exposing that space to sunlight. Examples include Trombe Walls, water walls, and thermal air panels. Our focus here is on indirect systems that are passive, in other words, the heat is transferred to another space without fans or pumps.
Hybrid Gain <<an attached sunroom is a hybrid of direct and indirect gain>>
- The large south windows of a sunroom provide direct gain. Depending on the depth of the sunroom the sunlight may penetrate into the adjacent rooms during the day. Interior doors and windows connecting to the sunspace open a larger contiguous space to receive the sun's energy during the day. The indirect gain is the energy stored in the interior mass (heavy materials - stone, adobe, water, concrete), which will radiate into the home as the room temperature drops below the mass temperature. The sunroom is usually closed off from the living space at night to reduce the heat loss of the home.
Solar Hot Water << generating hot water for both space heating and for domestic uses is integral to the architectural design of a building >>
- Passive uses of the sun's
energy can easily meet the hot water needs of a household,especially
for daily domestic activities. Basically there are two approaches
to heating hot water. One is called a "batch" system, wherein the solar collector is
the water storage. The second approach uses a flat plate panel
wherein the water or an antifreeze mix circulates through to
capture heat from the sun and transfer that heat to a remote
storage tank. The flat plate system can be made or designed to
work passively with careful design to ensure thermosiphoning
(hot water rises naturally, just as hot air does) will occur.
- Active solar hot water systems that we employ typically use a photovoltaic module to generate the electricity for a 12 volt DC circulating pump. I consider this system to be a hybrid of passive and active and implement this for winter radiant floor heating systems.
Solar Electricity << photovoltaic cells convert sunlight to direct current (DC) electricity ---- In homes we can use this power directly or invert it to 120 volts alternating current (AC) >>
- Photovoltaic (PV) cells are connected together to create a PV module. Within a module when the cells are wired together in series the voltage increases, in parallel the amperage increases. Most systems would wire several PV modules together to create an array large enough to meet the calculated needs of the users.
Solar Cooking << sun ovens provide a superb substitute for gas or electric ovens during the day and it is feasible to incorporate one in your home design >>
- On any sunny day, year around, sun ovens will heat up to boil water . In the sunbelt regions one can cook complete meals and sustain temperatures of 350ºF to 425ºF using well built prefabricated ovens or by making a do-it-yourself unit with recycled materials.