Solar heating

“ Jakarta, 26 March 1985
neiqhbouring developing countries, interstate cooperation in hydropower development could revolutionize supply potential, especially in Africa. 77. Solar energy use is small globally, but it is beginning to assume an important place in the energy consumption patterns of some countries. Solar water and household heating is widespread in many parts of Australia, Greece, and the Middle East. A number of East European and developing countries have active solar energy programmes, and the United States and Japan support solar sales of several hundred million dollars a year. ”

“ In buildings of the second class, such as residences, office buildings and hotels, we have been, as a rule, satisfied with sufficient heat, and have relied upon such ventilation as is secured by the natural circulation methods. In such buildings, therefore, the system of heating most used is that known as "direct radiation," in which radiators, or some form of radiating surface, are located in each room, and connected by an arrangement of piping to a central source of steam or hot-water supply. ”

“ The condensation of volume of the planets will give rise to great elevation of temperature, while their currents of electricity, poured into the sun, will, by their passage through its enormously compressed hydrogen atmosphere, produce intense heat, and this, rapidly communicated to the solar core within, will raise its temperature to that of the sun as we now see it, and permanently maintain it in that state of incandescence. ”

“ Henry Macauley, of Belfast, Ireland, has suggested a plan for making the sun do direct service in cooling the air it heats, by using Mochot's solar-engine to pump cold air into dwellings, factories, etc. ”

“ When we talk about transforming our energy system and moving away from fossil fuel and making our homes more energy efficient and building solar panels, moving toward solar thermal power, in the Southwest of this country—New Mexico, Arizona, Nevada—we have some of the best solar exposure in the entire world. ”

“ In the not distant future, in other countries, too, there will exist no other fuel than the sun, no other engines than those driven by solar heat. By that time no doubt the means of storing up this heat will have been discovered, for in our latitudes we shall have to make provision against cloudy days and seasons of rain, which unfortunately constitute the major part of the year.
It may appear to be a pleasant paradox to say that future generations, after the coal-mines have been exhausted, will have recourse to the sun for the heat and energy needed in manufacture and in domestic economy. ”

“ Many attempts have been made in tropical and sub-tropical climates to utilize the sun's heat directly for power, and Ericsson in Sweden, Mouchot in France, and Shuman in Egypt have built successful and efficient solar engines. ”

“ There is another utilitarian aspect of our study about which there is less public interest, but more real promise—I mean that which concerns the direct application of solar heat to arts and manufactures. These are now all using it indirectly—by the water, for instance, which it lifts into the clouds to turn the mills of Lowell or Lawrence, as it flows back to the sea, or by the coal which it stored in former ages to drive our engines to-day. ”

“ Once completed, this plant will be the first large-scale solar plant in the U.S. to actually store the energy it generates for later use – even at night. And it will generate enough clean, renewable energy to power 70,000 homes. ”

“ It will be well to understand a little more in detail how to heat glass structures, as temperature is, next to moisture, the most important factor of success. If steam or hot water is used in the dwelling house and a greenhouse of the lean-to type is used, the problem becomes a very simple one, as additional pipes can be run through the greenhouse. But as this advantage is not always ready to hand, we will consider the heating of an isolated house, and the principles involved may be adapted to individual needs. ”

“ As for directly storing up solar heat in good conductors or absorbents of heat which are then to be insulated—for instance, receiving the heat in porous black stones which are first exposed to the sun and afterward thrown into a great reservoir, just as snow is piled up in the ice-house—it involves no impossibility. ”

“ Although I can not pretend to an intimate acquaintance with the more intricate phenomena of solar physics, I have long had a conviction, derived principally from familiarity with some of the terrestrial effects of heat, that the prodigious dissipation of solar heat is unnecessary to satisfy accepted principles regarding the conservation of energy, but that solar heat may be arrested and returned over and over again to the sun, in a manner somewhat analogous to the action of the heat recuperator in the regenerative engine and gas-furnace. ”

“ Buildings could host over a third of PV potential
For building-based PV, the approach in this study is broadly consistent with other studies. Based on floor area, an estimate of sun-facing roof and fac ̧ade area is obtained, followed by a suitability factor. For the resulting available area the annual irradiation is multiplied by the system efficiency of the solar panel which results in the net potential. ”

“ Heat loss in buildings.—There have been considered in previous chapters the various kinds of radiators in use and the amount of heat given off by them under different conditions; and the subject now approaches a study of the particular way in which the heat is utilized. The object of any heating system is, of course, to maintain a uniform temperature in the building in question, and to do this it is necessary: First, to replace the heat lost by convection and radiation from the windows and walls of the building to the colder surroundings outside ”

“ For this reason astronomers generally, while conceding that a portion, and possibly a considerable fraction, of the solar heat may be accounted for by this hypothesis, are disposed to look further for their explanation of the principal revenue of solar energy. They find it in the probable slow contraction of the sun's diameter, and the gradual liquefaction and solidification of the gaseous mass. The same total amount of heat is produced when a body moves against a resistance which brings it to rest gradually, as if it had fallen through the same distance freely and been suddenly stopped. ”

“ The great difficulty, that of the perpetual renewal of the solar fuel, still remains unsolved; the fact that during the millions of years of geological history we find no indications of any declining average of solar energy is so far still unexplained by this, as by every other, attempt to account for the origin of solar and stellar light and heat. ”

“ We may say that it lends itself to every industrial use in which solar heat can be employed, especially in tropical countries where the absence of all kinds of fuel for industrial uses is severely felt. ”

“ Harnessing the Sun’s Energy
Historically, the sun’s energy has most often been used by concentrating it with a lens or mirror and then converting it to heat. We could do this and run a heat engine, but a more direct avenue is open.
About a decade ago it was found that the junction between p and n semiconductors would generate electricity if illuminated. This discovery led to the development of the solar cell, a thin, lopsided sandwich of silicon semiconductors. As shown in Figure 12, the top semiconductor layer exposed to the sun is extremely thin, only 2.5 microns. ”

“ Many attempts have been made to produce power directly from the sun through solar engines, or by concentrating it in furnaces. At the St. Louis Exposition a few years ago, a Portuguese priest exhibited a solar engine called a heliophore, in which, by means of the sun's rays, the temperature was raised to 6000 degrees F., and a cube of iron placed in it melted like a snowball. The sun helps to raise the tides and some day they may be used to produce power. ”

“ The warm air can carry the humidity, but the cold air does not do it as well, and when it strikes the warm air the latter is forced to condense.
Comfort is the main thing in the home, even more sometimes than saving fuel bills.
“Comfort,” says Professor Allen in an address, “is the prime consideration, more than maintaining a definite temperature. Getting the temperature right brings comfort. We should aim at 40% to 50% of moisture in the winter with 68 to 70 degrees.”
The fact is that the heating engineer to-day allows for about 1⁄3 more heating area when the house is not weather stripped. ”

“ Solar radiation provides the energy for photosynthesis, hence vegetation provides a storage reservoir for the sun's energy. This energy, often accumulated over years, is released quickly when the vegetation burns. In the absence of precipitation, the moisture content of dead fuel is affected to some extent by the fuel temperature, but the effect of relative humidity is much stronger. And for a given air mass, relative humidity is controlled almost entirely by air temperature, which in turn is closely related to solar radiation intensity. ”

“ The sun is thus, in effect, a self-compensating machine, and its passage through a region of increased electrical generation would first manifest itself in a vast increase of brilliancy, due to higher incandescence of its hydrogen envelope; this, in turn, would be communicated to the deeper structures of the sun, producing increased volatilization [196] and dark absorption bands, and finally to the whole solar mass, expanding its volume in proportion to the heat absorbed. ”

“ The actuating force of every wind that blows; of every mighty current that streams through ocean depths; the motive cause of every particle of vapour in the air of every mist and cloud and raindrop, is Solar Radiation.
“The delicate tremor of the sun’s surface particles, shot hither through thirty million leagues of fine intangible æther, has power to raise whole oceans from their beds, and pour them down again upon the earth. We are apt to measure solar heat merely by the sensation it produces on our skin, and think it small and weak accordingly; a good coal fire will heat us more. ”

“ Abstract Nearly all long-term energy projections rely heavily on renewable energy sources on the assumption of abundance. Yet, already today, wind and solar projects can encounter local objections and competition with other uses. This paper presents the ranges of realistic potential supply for solar and wind electricity, using a 1 km 2 grid level analysis covering the whole world at country level. In addition, the potential for building-based solar electricity is assessed. ”

“ Solar electricity production The potential per area for solar electricity production can be calculated from the solar energy incident upon the surface per year and the conversion efficiency of the harvesting technology, as shown in Eq. (4) .
where P/A = potential per area in EJ/km2 per study period and technology (PV vs CSP) ; p = the study period (2010, 2030, 2070) ; t = the technology (PV or CSP) ; I = resource intensity in J/m2 for solar irradiation; E = conversion efficiency in % by technology. ”

“ What is the longest mission where the total weight of the fuel cell will be less than the weight of the nuclear power plant?
26 SOLAR CELLS Photons as Energy Carriers
All our fossil fuels, such as coal and oil, owe their existence to the solar energy stream that has engulfed the earth for billions of years. The power in this stream amounts to about 1400 watts per square meter at the earth, nearly enough to supply an average home if all the energy were converted to electricity. The problem is to get the sun’s rays to yield up their energy with high efficiency. ”

“ Modern heating arrangements are capable of maintaining large buildings at a summer temperature even in the coldest weather, but in order to do this at reasonable cost the building must be made as nearly air-tight as possible. The temperatures secured through artificial-heating plants have also brought another evil. The air raised to a high temperature is abnormal in humidity because it is taken from outdoors, where it is cold and the humidity is low, and is raised by heating to a condition where it can absorb a great quantity of moisture. ”

“ It seems, therefore, most probable that we can not for the future reckon on more of solar radiation than, if so much as, twenty million times the amount at present radiated out in a year. It is also to be remarked that the greatly diminished radiating surface, at a much lower temperature, would give out annually much less heat than the sun in his present condition gives. ”

“ A Lesson from the Coal-Pits.
We require in our houses an artificial temperate climate which shall be uniform throughout, and at the same time we need a gentle movement of air that shall supply the requirements of respiration without any gusts, or draughts, or alternations of temperature. Everybody will admit that these are fundamental desiderata, but whoever does so becomes thereby a denouncer of open-grate fireplaces, and of every system of heating which is dependent on any kind of342 stoves with fuel burning in the rooms that are to be inhabited. ”

“ Researching and comparing performance of solar-powered distributed air conditioning systems in different regions of the country, including potential integration with other onsite systems, such as solar, biogas, geothermal heat pumps, and propane assist or combined propane fuel cells, with a goal to develop site-specific energy production and management systems that ease fuel and peak utility loading. ”