ENERGY RESOURCES(ME-302)GROUP-10

MEMBERS:-HAMMAD AHMED JAVAID (2011-ME-25)ALI SHAN AJMAL (2011-

ME-29)USMAN KHALID (2011-

ME-39)MUHAMMAD UMAIR AHSAN (2011-ME-19)AAMIR ALI IDREES (2011-

ME-11)

DEPARTMENT OF MECHANICAL ENGINEERINGUCE&T, BZU, MULTAN

TOPICS TO BE DISCUSSED What Is Solar Energy System? Types Of Solar Energy System.

Passive Solar Energy System. Active Solar Energy System.

Solar Heating Of Buildings (Active System) Passive Solar Heating And Cooling Of Buildings

Five Elements Of Passive Solar Home Design

Advantages And Disadvantages Active Solar Heating Passive Solar Heating

SOLAR ENERDGY SYSTEMSolar Energy System or Solar Power System, is a stand-alone system, entirely powered by solar energy to harness different types of energies.Solar Energy System are broadly characterized as either Passive Solar or Active Solar depending on the way they capture, convert and distribute solar energy. Active Solar Energy Systems include the use of photovoltaic

panels and solar thermal collectors to harness the energy. Passive Solar Energy Systems include orienting a building to

the Sun, selecting materials with favorable thermal mass or light dispersing properties, and designing spaces that naturally circulate air.

PASSIVE SOLAR ENERGY SYSTEMSAncient people used passive solar energy systems. They build their houses

out of stone or clay, which absorbed the sun’s heat during the day and stayed warm after dark, providing heat throughout the night.Builders today use similar methods for passively capturing solar energy. For example, they construct houses with large double- or triple-paned windows that get direct sunlight to capture and magnify the sun’s warmth. The effect is similar to but more powerful than what happens to your car on a sunny day: The air inside becomes much warmer than the air outside because the windows let in the sun’s energy and trap it, gradually raising the temperature.Other effective methods of passive solar energy capture include using stone flooring and walls with thick insulation to keep the energy in buildings. With carefully placed windows and other architectural techniques, passive solar energy systems can be an effective way to heat buildings

ACTIVE SOLAR ENERGY SYSTEMSActive Solar Energy Systems use the same principles as passive

systems except that they use a fluid (such as water to absorb the heat) and some electrical or mechanical equipment (such as pumps and fans) to increase the usable heat in a system. A solar collector positioned on the roofs of buildings heats the fluid and then pumps it through a system of pipes to heat the whole building.Photovoltaic Cells, or Solar Panels, are slightly more involved than active solar energy systems. They convert sunlight to electricity by using thin sheets of silicon. These thin sheets are inexpensive and can be added to roof tiles. People in remote areas such as mountain tops and islands often use photovoltaic cells to generate electricity in their homes and businesses.This figure illustrates how solar panels capture sunlight and generate electricity.

ACTIVE SOLAR ENERGY SYSTEMS

SOLAR HEATING OF BUILDINGS(ACTIVE SYSTEM)

SOLAR HEATING OF BUILDINGS (ACTIVE SYSTEM)Active Solar Heating Systems use solar energy to heat a fluid -- either

liquid or air -- and then transfer the solar heat directly to the interior space or to a storage system for later use. Most solar water heaters use heat exchangers to absorb sunlight with glycol and transfer the warmth to water. But glycol is difficult to work with, as it is very viscous, easily leaks and contaminates, and turns into dangerous acid if it oxidizes with aluminum and other metals.A very cheap and easy way to use the sun to heat incoming water is to simply run the pipes outdoors through insulated glass. Copper pipes zigzag through an insulated box with a glass top and black bottom, maintaining the same water pressure. These pipes are painted black to absorb the heat that gets trapped in the box.

SOLAR HEATING OF BUILDINGS (ACTIVE SYSTEM)

SOLAR HEATING OF BUILDINGS (ACTIVE SYSTEM)

Evacuated Tube Collectors use a vacuum between the pipe and a tube around it to insulate heat from escaping. But a much cheaper way is to stack plastic soda bottles, trapping air pockets as with the soda can solar chimney. Aluminum cans can be cut into broad arcs and placed at the bottom to reflect heat to the pipes.The amount of heat that can be absorbed when the sun is shining is incredible, so include a pressure release valve. Drain the pipes in the winter and bypass the water directly to the water heater when it gets too cold outside to be effective. By supplementing a water heater with a solar heated water first, a lot less energy is needed to get the water hot.

SOLAR HEATING OF BUILDINGS (ACTIVE SYSTEM)Liquid-Based Active Solar Heating

Solar Liquid Collectors are most appropriate for central heating. They are the same as those used in solar domestic water heating systems. Flat-plate Collectors are the most common, but evacuated tube and concentrating collectors are also available. In the collector, a heat transfer or "working" fluid such as water, antifreeze (usually non-toxic propylene glycol), or other type of liquid absorbs the solar heat. At the appropriate time, a controller operates a circulating pump to move the fluid through the collector.The liquid flows rapidly, so its temperature only increases 10° to 20°F (5.6° to 11°C ) as it moves through the collector. Heating a smaller volume of liquid to a higher temperature increases heat loss from the collector and decreases the efficiency of the system. The liquid flows to either a storage tank or a heat exchanger for immediate use. Other system components include piping, pumps, valves, an expansion tank, a heat exchanger, a storage tank, and controls. The flow rate depends on the heat transfer fluid.

SOLAR HEATING OF BUILDINGS (ACTIVE SYSTEM)Storing Heat in Liquid Systems

If the solar system cannot provide adequate space heating, an auxiliary or back-up system provides the additional heat. Liquid systems store solar heat in tanks of water or in the masonry mass of a radiant slab system. In tank type storage systems, heat from the working fluid transfers to a distribution fluid in a heat exchanger exterior to or within the tank.Tanks are pressurized or unpressurized, depending on overall system design. Before choosing a storage tank, consider cost, size, durability, where to place it (in the basement or outside), and how to install it. You should also note how much insulation is necessary to prevent excessive heat loss, and what kind of protective coating or sealing is necessary to avoid corrosion or leaks.Specialty or custom tanks may be necessary in systems with very large storage requirements. They are usually stainless steel, fiberglass, or high temperature plastic. Concrete and wood (hot tub) tanks are also options. Each type of tank has its advantages and disadvantages, and all types require careful placement because of their size and weight. It may be more practical to use several smaller tanks rather than one large one.The simplest storage system option is to use standard domestic water heaters. They meet building codes for pressure vessel requirements, are lined to inhibit corrosion, and are easy to install.

SOLAR HEATING OF BUILDINGS (ACTIVE SYSTEM)Distributing Heat for Liquid Systems

You can use a radiant floor, hot water baseboards or radiators, or a central forced-air system to distribute the solar heat.In a radiant floor system, solar-heated liquid circulates through pipes embedded in a thin concrete slab floor, which then radiates heat to the room. Radiant floor heating is ideal for liquid solar systems because it performs well at relatively low temperatures. A carefully designed system may not need a separate heat storage tank, although most systems include them for temperature control.Hot-water baseboards and radiators require water between 160° and 180°F (71° and 82°C) to effectively heat a room. Generally, flat-plate liquid collectors heat the transfer and distribution fluids to between 90° and 120°F (32° and 49°C). Therefore, using baseboards or radiators with a solar heating system requires that the surface area of the baseboard or radiators be larger, temperature of the solar-heated liquid be increased by the backup system, or a medium-temperature solar collector (such as an evacuated tube collector) be substituted for a flat-plate collector.There are several options for incorporating a liquid system into a forced-air heating system. The basic design is to place a liquid-to-air heat exchanger, or heating coil, in the main room-air return duct before it reaches the furnace. Air returning from the living space is heated as it passes over the solar heated liquid in the heat exchanger. Additional heat is supplied as necessary by the furnace. The coil must be large enough to transfer sufficient heat to the air at the lowest operating temperature of the collector.

PASSIVE SOLAR HEATING AND COOLING OF BUILDINGS

SOLAR HEATING OF BUILDINGS (PASSIVE SYSTEM)

The amount of energy spent on heating and cooling homes can be severely reduced by using simple design techniques. Building materials and structural design greatly impact the temperature inside a space. A building can use the power of the sun to heat or cool itself, with techniques that were developed over thousands of years in distant parts of the world. These techniques are cheap, saves money, and helps the environment.

SOLAR HEATING OF BUILDINGS (PASSIVE SYSTEM)FIVE ELEMENTS OF PASSIVE SOLAR HOME DESIGN

The following five elements constitute a complete passive solar home design. Each performs a separate function, but all five must work together for the design to be successful. APERTURE (Collector)

The large glass (window) area through which sunlight enters the building. Typically, the aperture(s) should face within 30 degrees of true south and should not be shaded by other buildings or trees from 9 a.m. to 3 p.m. each day during the heating season.

ABSORBER The hard, darkened surface of the storage element. This surface—which could be that of a masonry wall, floor, or partition (phase change material), or that of a water container—sits in the direct path of sunlight. Sunlight hits the surface and is absorbed as heat.

SOLAR HEATING OF BUILDINGS (PASSIVE SYSTEM)FIVE ELEMENTS OF PASSIVE SOLAR HOME DESIGN

THERMAL MASS The materials that retain or store the heat produced by sunlight. The difference between the absorber and thermal mass, although they often form the same wall or floor, is that the absorber is an exposed surface whereas thermal mass is the material below or behind that surface.

DISTRIBUTION The method by which solar heat circulates from the collection and storage points to different areas of the house. A strictly passive design will use the three natural heat transfer modes—conduction, convection, and radiation—exclusively. In some applications, however, fans, ducts, and blowers may help with the distribution of heat through the house.

CONTROLRoof overhangs can be used to shade the aperture area during summer months. Other elements that control under- and/or overheating include electronic sensing devices, such as a differential thermostat that signals a fan to turn on; operable vents and dampers that allow or restrict heat flow; low-emissivity binds; and awnings.

SOLAR HEATING OF BUILDINGS (PASSIVE SYSTEM)Overhangs:

Size roof overhangs so that the summer sun is blocked but so that the lower winter sun is let through. Consider the height of the sun in these seasons for the length of your roof eaves. The height of the sun in summer and winter depends on your elevation. This direct sunlight will heat spaces considerably in the winter. But unless you live in a very cold climate, you don't want this heat gain in the summer.

SOLAR HEATING OF BUILDINGS (PASSIVE SYSTEM)Horizontal Shades South/North & Vertical Shades East/West:

Space out horizontal louvers as you would an overhang, so that summer sun is blocked and winter sun is let through. Most louvers are rigid, but if you can get louvers that are adjustable like interior shades that would probably prove handy. The rising and setting sun is low to the horizon, so vertical louvers are probably best on the East and West.

SOLAR HEATING OF BUILDINGS (PASSIVE SYSTEM)Outside Objects Shade Sun:

Outside elements such as mountains and structures help block the sun. Trees and bushes are excellent for filtering sunlight. Deciduous trees drop their leaves in the winter, allowing sun in the winter but blocking sun in the summer.

SOLAR HEATING OF BUILDINGS (PASSIVE SYSTEM)

Inside Objects Filter Sun : Objects in the room can likewise block or filter sunlight. Water elements like fish tanks are great because they soak up heat and mitigate temperatures.

Indirect Lighting: Indirect lighting sources provide healthy bright sunlight with less heat gain. The exterior of the building should use such reflections to illuminate interior spaces.

SOLAR HEATING OF BUILDINGS (PASSIVE SYSTEM)Courtyards :

Thermal mass materials work best in use together with courtyards or porches. A central outside space provides a way for the material to shed its heat. The heat stack effect literally sucks heat out of the building and up into the courtyard.Conversely, cold regions should not have courtyards and the building's shape should be as compact as possible. A cube-shaped building will conserve energy much better than a long flat building.

SOLAR HEATING OF BUILDINGS (PASSIVE SYSTEM)SOLAR TOWERS FOR NATURAL DRAFTS & HEATING

Many homes have tall front entrances. They naturally provide cooler temperatures. If the insulation at this tall space is thinner than everywhere else, sunlight radiation will heat up the ceiling. As this hot air vents through an upper window it will suck up cooler air from below, creating a natural draft and cooling the entire house. This is known as the Stack Effect.

SOLAR HEATING OF BUILDINGS (PASSIVE SYSTEM)But what about the winter?

Even with the upper window closed, this warmer air will suck up air and create an unwanted draft. The best thing to do is isolate this solar tower to its own room that can be opened or closed with a door. It can provide a cooling draft in the summer and be isolated away behind closed doors in the winter.

SOLAR HEATING OF BUILDINGS (PASSIVE SYSTEM)SOLAR CHIMNEY

A very effective and low-cost device that rarely gets used is the solar chimney. It is particularly effective for creating a draft in humid, hot climates that have very few options for cooling. A long flat chimney faces the sun and is painted black so that the air inside heats up. This air vents out the top and sucks out the air below.The important thing to make this work is to make these chimneys long and thin. The important principles behind the stack effect is area of air flow and height of the chimney.

SOLAR HEATING OF BUILDINGS (PASSIVE SYSTEM)It could also heat the house in the winter. Close off the upper chimney

with a damper and allow the heated air to enter back into the room. A popular variation of this is the soda can heater. Air flows from can to can in little pockets, which gives it a chance to really heat up before it vents out of the top.

SOLAR HEATING OF BUILDINGS (PASSIVE SYSTEM)

SOLAR HEATING OF BUILDINGS (PASSIVE SYSTEM)The most important thing to prevent heat loss or gain in any roof is

insulation. But with the cold roof, the attic is ventilated to shed any heat that does escape from the house and prevent ice dams and icicles on the roof.Continuous inlet vents at the eave soffits allow cool air to enter the space and warm up as heat is leaked out of the house and vents out continuous ridges at the top.

SOLAR HEATING OF BUILDINGS (PASSIVE SYSTEM)

ADVANTAGES AND DISADVANTAGESACTIVE SOLAR HEATING

Advantages:Renewable resource that is environmentally friendlyAvailable anywhere on EarthUsed to provide heat, lighting, mechanical power and electricitySource is Free – significantly reduced gas bills

ADVANTAGES AND DISADVANTAGESACTIVE SOLAR HEATING

Disadvantages:Array of Solar collectors takes up a lot of spaceDust, smoke, and weather conditions affect the performance of solar collectorsDependent upon time, season, and latitudeSilicon used for making photovoltaic cells is not in large supply

ADVANTAGES AND DISADVANTAGESPASSIVE SOLAR HEATING

Advantages:Passive solar design is highly energy efficient, reducing a building's energy demands for lighting, winter heating, and summer cooling. Energy from the sun is free. Strictly passive designs capture it without additional investments in mechanical and electrical "active solar" devices such as pumps, fans and electrical controls.Passive solar design also helps conserve valuable fossil fuel resources so that they can be directed toward other uses.Passive solar design also reduces greenhouse gases that contribute to global warming because it relies on solar energy, a renewable, nonpolluting resource.

ADVANTAGES AND DISADVANTAGESPASSIVE SOLAR HEATING

Disadvantages: Passive solar design costs little more than conventional building design and saves money over the long run. In addition, room and furniture layouts need to be planned carefully to avoid glare on equipment such as computers and televisions. And along with daylight comes heat. During the summer or in consistently warm climates, daylight could actually increase energy use in a building by adding to its air-conditioning load.