The usage of air conditioning is not prevalent until the 21th century in Chine. Therefore, ventilation is an emphasis when designing building in terms of adjusting temperature and humidity. The dynamic movement of air is generally realized by two means: wind pressure and temperature pressure. Wind pressure is generated as density of air varies and temperature pressure is due to temperature difference.
Wind pressure
Temperature pressure
1) The arrangement in big scale is base on the rule: shades behind and sunlight in front. The ideal location of a building would be at the foot of mountain and face water. Thus temperature pressure is created to provide wind flow.
2) Orientation should be in favor to the most frequent wind flow direction. In the northern part where ventilation is not the primary concern, buildings are oriented in north-south direction to obtain maximum light radiation.
3) Use of courtyard to introduce air above to exchange with the air between the houses. When front courtyard and back courtyard is placed, airflow is realized horizontally. 
Shenzhen a modern young city in China is noted for her hot and humid tropical climate.
Without appropriate design, a building can consume a large amount of energy to achieve human comfort. Therefore, sustainable design is extremly important in this city and the design by BIG for Shenzhen Energy Company serves as a good example of applying passive and actively designs in a tall building.
Passive:
1) folded skin of façade to shade the office complex from direct sunlight
2) the folded skin also provide closed and open parts which serve complementary functions. The closed parts insulate heat and block firect sunlight. The open parts provide ventilation for the office rooms.
3) curtain walls to insulate the wall, which could be a source of major heat gain when glass is applied.
Active:
1) Solar thermal panels
Crystal Cathedral, located in Garden Grove, California, is designed by Philip Johnson and John Burgee under the request from Dr. Robert H. Schuller. He wanted a building that brings people closer to the sky and the sun which “sparkle through our wonderful sanctuary”, thus the roofs and walls are made of almost entirely glass-crystal-clear glass. Due to this reason, many people might think this building is at a risk of having green house effect and will require a large amount of energy input for cooling and heating. However, quite the opposite is true. Air conditioning is not applied in this building but passive design is used to ensure the habitable environment.
Heat Gain
Radiation: Heat gain is mainly through direct sunlight. More than 10000 pieces of glasses constructed the walls and roofs. The silver-coated, reflective glass screens out large amount of light and only allow about 8% sunlight, which accounts for the small amount of solar gain. The reflective facets of the bell tower to the north and a pool to the east are sources of indirect light. Hear gain from people from 8:00 a.m. to 11:30 a.m. is a source of heat gain, too, which can be transmitted from human to the environment by heat radiation, convection during respiration and conduction, when skin is in conduct with building structure.
Convection: The 90 foot tall door near the pulpit allows heat from solar radiation of the asphalt paving to enter.
Conduction: As light heat up the facets, glass conducts heat from outside to inside since it is not insulated. Heat from outside can be further conducted by the aluminum grid, which holds the glasses, and further by the tubular steel attached. Heat flows from underground pipes regulates temperature in cold weather. During a cold weather, which last for about one month, spots heating is used in this building.
Reduction of heat gain
Ventilation: large envelop heat transfer is increased by motorized operable panes scattered across the facades and through the door near the pulpit. More than 550 movable panels are placed on the sides and ceiling, creating chimney-like effect. Cooler and fresh air breeze into the building provide efficient cooling, whereas the interior temperature can rise into the 90s without these panels. Fresh air flowing from the ground level through the giant door generates convection between the clerestory windows, which is controlled thermostatically.
Use of daylight: Sun light is the major light source during day time service, thus the heat produced by electrical equipments, which can be two to four times more than heat produced by daylight illumination, is in a minor amount.
Color of paint: The frame is made of white steel trusses and white can reflect most amount of light. The huge marble columns supporting the balconies have white color, too.
Conclusion
When heat in a building exceeds the human comfortable level due to solar or internal gains, ventilation can reduce heated storage efficiently. This proves a statement in “Ecology.Design.Synergy”: “internal temperature of buildings is determined primarily by energy transfer across their enclosures and not by their solar or internal gains.” However, this situation is useful for a building in a mild climate. That is why Johnson emphasized that “It’s an Orange County cathedral. It couldn’t be built anywhere else.”
Extension
Benefits on sunlight: 1. It is highly correlated to the productivity of people. A research stated an increase of 15-50%. 2. Containing the full spectrum of energy wavelength, daylight satisfy the demand of human body. 3. Daylight is efficient in lighting up a space. One side exposure to daylight can provide a bright space to a depth 2.5 times the height of the room. 4. Use of electricity is minimized when using nature light to light a building, thus heat gain through artificial light is cut down.
Resources:
Click to access balance_point_big.pdf
http://www.crystalcathedral.org/about/architecture.php
http://www.seeing-stars.com/churches/crystalcathedral.shtml
http://www.areavibes.com/garden+grove-ca/weather/
Behnisch and Transsolar, “Ecology.Design.Synergy”
Peter Blake, “Philip Johnson”
Hilary Lewis and John O’Connor, “Philip Johnson, the Architect in His Own Words”
Sun is a huge source of energy without question. This can be proved when tracing the origin of all kinds of objects on this planet. Sun offered benefits automatically to allow plant growth, which is the fundamental element for further production of good. Meanwhile, its value is never restricted in this aspect, but is extending in a broad and effective way as more methods utilizing solar energy is developed.
I. Active Solar Design
Active solar design mainly refers to solar collecting devices that collect solar energy and it later used, stored, or transformed. The most common usage of active solar device are solar collectors, which can be divided into flat plate collectors and evacuated tube collectors, both use to heat cool water.
• Flat Plate Collectors
They consist of a space enclosed by house and transparent cover thus water flow through a series of pipes is heated up by a black solar absorber. “Greenhouse effect” is used in this technology, which takes place when the glazing material absorb wavelength emitted by the sun and reflect the outreaching sunlight back into the space, thus continue to heat this space.
• Evacuated Tube Collectors
This device consist of a group of absorber strips, which is pressured to flow through the collection tube as solar fluid in this tube are evaporated when heated. The advantage of this type of collectors is that they protect the absorber plate from corrosion. However, the anticipated cost might be higher.
II. Passive Solar Design
• Temperate and arid climate
While using active solar design to obtain extra energy, passive solar energy ensure energy will not be redundantly spend to maintain the comfort level in a building. Though can be seen in humid tropical climate, passive solar design is more frequently suited to the temperate and arid climate. The energy collecting process can be categorized into direct heat gain and indirect heat gain.
1. Heating Cycle (Direct Gain)
In cold and dry climate, the north-facing wall should be approximately 1/5 of the floor area of the rooms in order to be warmed by heat gain.
a. Use concrete as structural elements, wall panels and floor slabs. As concrete is not a good transmitter of heat, heat loss can be controlled between outside low temperate and inside warm environment.
b. Insulate windows by curtains. Use double glazing or insulated window shutters in severe cold climate.
c. Insulate ceiling.
d. Eliminate wall penetrations to prevent heat loss from air leaks.
e. Thickening the slab to reduce heat loss to ground.
f. Insulate the floor edges, especially the northern edge.
2. Indirect Gain
a. Trombe-Michel Wall
The wall designed by Dr Felix Trombe and Jacques Michel, has black-painted 24inch thick concrete south wall collecting solar energy, and a double glazing glass to prevent heat loss. Cold air from the room is heated up by convection at this wall surface.
b. Water Wall
The principle used by water wall is similar with that of the Trombe-Michel Wall. Water wall is better than the latter because of its high heat capacity thus over heating is less likely to occur. However, constructors should pay attention to containment, corrosion and flood risk problem when applying water walls.
c. Roof Pond
This employs water contained in 8inch deep PVC bag, place on steel decking roof and covered by flexible insulator. As the water is heated up by the sun, steel ceiling of the room rise in temperature by conduction and room can thus be heated by radiation from the ceiling.
d. Attached/Isolated Sunspace
This method is applied in a bigger scale in a house that air in the whole building is forced to circulate as temperature is differentiate in rooms. The example of Unit 1 of First Village, Santa Fe, can explain this principle explicitly.
e. Thermosyphon System
This system can be a loop of air of water, driven to flow by the difference in weight per unit volume between the heated and unheated material. The diagrams below illustrate a typical thermosyphon loop and present the section of the Paul Davis house, which used thermosyphon collectors for space heating.
• Hot and Humid Climate1: Cooling Cycle (Direct Gain)
a. Cross-ventilation
b. Provide instantaneous cooling when inside temperature is higher than outside temperature
c. Eliminate heat stored in building fabric overnight
d. Provide evaporative cooling
e. Plant trees on the northern and western side
f. Choose suitable insulation material for ceiling and roof
Sources:
Passive Solar Heating Design, Ralph M. Lebens
Principles of Passive Solar Building Design, Cyril Carter, Johan De Villiers
http://www.azsolarcenter.org/tech-science/solar-architecture/solar-application-and-integration.html
http://www.esru.strath.ac.uk/EandE/Web_sites/01-02/RE_info/active_solar.htm
The increasing population leads to the expanding of consumptions and a further issue emerges: energy problem. After tracing energy flows in a diagram, the connections often end with nonrenewable resources, including coal, oil and gas. The dependence on these sources worsens the energy problem even more. The movie, Shishmaref, Alaska, depicted an extreme example of energy problem and also presented some solutions.
In universities, students and faculties specified their experiments on solar cars, which is a great way of reducing the usage of the original energy type and take advantage of abundance energy, or can be seen as a renewable energy. Some people are advocating a civilization that promotes social and environmental sustainable development. They are trying to restore the existing factors today rather than degrade them, thus business that use sunlight as an energy source is encouraged, so does wind energy in generating electricity. In addition, the idea of developing a network of transforming energy programs is stressed in this movie. The examples are efficient housing, efficient cars and natural powers.
As this two energy forms are introduced in the course, I began to question the relation of light and heat. Heat can be produced by light and light also can be produced by heat. Are they exist at the same time or one is the transform of the other? The answer can be explained with a loop.
If we start with light, the combination of visible light and infrared, it generates thermal radiation which cause increasing in temperature when applied to an object. Thermal radiation, as an electromagnetic wave, has greater energy (heat) with short wavelength. Because of its undulatory property and particle nature, the energy it contained is able to transmit to the object. When the energy of an object is high enough, visible light might be emitted from it. The tungsten filament in light bulbs is a good example. Even if the temperature is not very high, infrared light is constantly emitted when it’s above zero degree Kelvin. Therefore, light and heat coexist and they can be transformed from one to another.
I understood the importance of a healthy ecosystem in a place after watching a movie. The intervale of Burlington used to be a productive land attracting farmers to work and settle due to its soil type and geographic features. Before the mid twentieth century, this place continued to offer people prosperity and happiness: pine and oak trees at the riverbank provided them lumber and potash, which is a raw material for dyes, gunpowder, soap and ceramic; crops in the farm land gave people food.
In the movie, the degradation of this environment is brought by the development of cities, but I doubt the sustainability when the residents ceaselessly exploited this rich land. As people were mainly depending on nonrenewable sources such as trees and soil, the frequency and amount of utilizing these resources should be carefully examined to ensure they were not being depleted.
The situation described could be a potential crisis for this intervale, while the real deterioration was when the intervale became Burlington’s junkyard, public dump place, trash burning plant, sewage sludge repository and wood-fired electricity producing power plant. The improvement was made when organic economy and ecology was introduced: the agricultural system is a production cycle providing local food; it also offers children learning programs. Thus the community was prosperous and energetic again. Though this example described in this movie is somewhat extreme, the significance of a sustainable program in every situation should not be neglected.
The reading from Lechner about solar geometry informed us three types of solar spectrum: visible, short-wave infrared and ultraviolet, thus we are able to assess light’s effects in a more detailed way.
The visible light has many unique properties. First, the visible light with color can be mixed. For example, white light is obtained if you mix blue and yellow light, or green and orange light. Color should be carefully used in a building since different color might post different psychological effects. Second, the visible light is the only effective light for plants’ photosynthesis, thus it must be present for the plant to be alive and its absence will lead the plants to death. Third, visible light with long wavelength is a source for heat, thus if a place is designed to be warm, red light should be introduced.
Infrared light is an invisible light which is generated by objects about zero degree Kelvin. Thus this type of light is closely related with the heat transmitting and generating. Its other applications are thermography, communication, spectroscopy and so on. Because these two types of light are only sources of thermal radiation, they are essential in thermal transmission in vacuum.
Ultraviolet light is regarded as the more influential and harmful among the three types of light exist on earth. It is significantly beneficial if rightly used: hospitals use it for sterilizing; bone growth is strengthen by ultraviolet; some skin diseases can be cured by it; vitamin D, a needed nutrition in human body, is synthesized with the presence of ultraviolet. On the other hand, it caused skin aging, skin disease and even skin cancer if it is presence in excess. Therefore, the amount of ultraviolet should be controlled to use it in a most efficient way.
From last discussion, we all agreed that sun is one of the basic sources for substances we consume every day. Being an origin of everything, sun displayed its significance in every aspects of life. Because of its omnipotent, more efficient usages of solar energy should be developed to gain more benefits.
As I explore the energy system from the body to the world, I met a difficulty when constructing the diagram, which is to keep the diagram clear and easy to understand. More interactions can be found as more sectors in this energy system participate in the diagram, thus it is important to both classify the sectors and group the interactions. The basic interactions in a system could simply be represented by positive and negative signs, i.e. inflow heat is positive and outflow heat is negative. The sectors can be separated according to amount, frequency, time, etc. The path of the energy flow can be represented in different colors, and the shape of the path can be in straight lines or curves in order to indicate various characters of the energy path.
By doing this assignment, I learnt that the path for a particular subject can be roughly defined if it is non-biodegradable. For example, metal, plastic and glass have path ways either being permanent waste or recycling back to the system. Whereas the biodegradable materials has numerous ways to interact with other sectors in the system and their path are more divers and more complex to trace. At the same time, the biodegradable materials degrade from a substantial subject to an energy type as they interaction carry on, thus they post less burden to environment. In comparison, only a minor amount of the non-degradable waste can be recycled and the rest has inevitable effects on the environment. This reminds us to be mindful when using energy to produce the non-degradable products therefore the benefit can be maximized and energy is efficiently used.
I could not find an energy path back to the sun due to the distance. However, if the sun is referring to heat, then there are ceaseless processes of heat outflow from human body. The activities include respiration, excretion and heat exchange by skin. While performing daily activities, all kinds of machines are used which are powered by various energy types and has heat loss during their performance.
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