Week 8

 Mechanical Systems 

Gina Christopher 

SOURCES OF FUEL 

Both mechanical and electrical systems require a fuel source in order to operate. Sources of fuel include bioenergy, fossil fuels, hydrogen, nuclear energy, wind power, solar, hydropower, and fusion. Some of these sources are sustainable, and others are not. Bioenergy is produced from organic matter such as corn, municipal waste, and wood. Fossil fuels provide over 85 percent of the fuel for electricity in the U.S. Coal is a naturally occurring fuel that can be obtained either through underground mining operations or strip mining. Hydrogen is a commonly occurring element and can be made from fossil fuels and renewable sources such as wind, geothermal, and solar. Nuclear energy has been a subject of debate in the U.S. for a long time. The primary reason is that radioactive material is produced which must then be stored for millions of years. Wind turbines are placed on the landscape to capture the prevailing winds and convert them to energy in the form of electricity. Solar energy comes from the sun. Hydropower is generated by water and is a renewable source. Fusio-produced energy is a current area of research, as is plasma research. The DOE is exploring both as possible energy sources for the future. 

FUEL CONSIDERATIONS

The choice of fuels must be tempered by a variety of concerns including cost, availability, and environmental impact. Scientists agree that greenhouse gas emissions as the result of burning various fossil fuel sources have led to global warming. Scientists also agree that we have reached a point where our consumption of oil is outpacing our ability to extract it from the earth, known as "peak oil". 

MECHANICAL SYSTEMS

Power produced from the different fuel sources can be used to power various types of mechanical systems. The common term for interior heating and sir systems is HVAC. HVAC stands for heating, ventilation and air conditioning. The goal of HVAC systems is to provide human comfort. 

HUMAN COMFORT 

Human comfort varies from culture to culture as well as person to person. In the United States, most have come to expect interior spaces that have a fairly consistent interior temperature. How comfort is experienced is the result of a couple of factors including temperature and relative humidity. A psychrometric chart demonstrates what is generally accepted as the comfort zone for most people. 

HEATING SYSTEMS 
Heat comes in three forms: latent; sensible, and radiant. Sensible heat is measured using a thermometer. Latent heat marks a state change such as solid to liquid or liquid to gas. Radiant heat is a form of electromagnetic radiation. There are several types of heating systems including hydronic, electric, wood and geothermal. In hydronic systems, boilers are used to heat water to provide either hot water or steam for heat. In electric systems, radiant heating relied on heating the surfaces of a space. The two primary types of radiant systems include radiant panels and radiant floors. Electric systems include forced air, furnaces, and electric resistance. Wood stoves/fireplaces have traditionally been used as a source of heating for historic buildings as well as for off-the-grid buildings. Today, it is possible to pure high-efficiency wood-burning stoves that include catalytic converters that burn combustible gases, thus reducing the resultant air pollution. 

GEOTHERMAL SYSTEMS 

Geothermal systems include natural occurring energy obtained from below the earth's surface and are either closed loop or open loop. Ground loop heart-pump systems use either water or antifreeze that circulates through a closed loop. In surface-water heat-pump systems the heat-exchanger loop is located a minimum of ten feet beneath a body of water. Water pumper from a well is used for a groundwater heat-pump system.

COOLING SYSTEMS 

Cooling can be provided to a space in 3 ways: by avoiding heat gain, by passive cooling strategies, and by mechanical cooling. Examples of heat avoidance include taking advantage of wind, avoiding direct sunlight, and allowing breezes. Examples of passive cooling include front porches, ventilation towers and central stairs. Examples of mechanical cooling include a split system, packaged unit, or through-wall unit. 

TYPES OF MECHANICAL COOLING SYSTEMS 

There are several types of cooling systems, including central station systems, split systems, packaged units, and though-wall systems. Large buildings use a central station system. A split system is used in smaller buildings, including some residential applications. A packaged unit is placed on the rood with one unit for each zone. A through-wall unit has the evaporator coil and fan on the inside, and a condenser coil, fan and compressor on the outside. Many interior spaces require air treatment in the form of humidifying or dehumidifying to meet the comfort zone on a psychrometric chart. 

COMMISSIONING 

Commissioning refers to the process by which all new equipment is checked to make sure it is working according to manufacturer recommendations. Quality-assurance activities include checking shop drawings, demonstrating the equipment, training owner personnel, testing, adjusting and balancing HVAC, and commissioning. Basic commissioning is a prerequisite in the LEED Green Building Rating System.

IMPACTS TO INTERIOR DESIGN 

An interior designer does not get involved with the design of mechanical systems, but the placement of ducts, registers, and returns are an integrated part of the design. Coordination of these items with light fixtures, sprinkler heads, ceiling-mounted equipment such as projectors and screens, smoke detectors, and ceiling design details ensure that the design intent and functional properties of the space are recognized. The designer might also be involved in locating the thermostat. 

 

SOLAR POWER

Renewables are energy sources that are not limited and are constantly refreshed. These include solar power, wind power, hydropower, biomass wood and geothermal sources. I choose to research more about solar power. Solar power is the conversion of energy from sunlight to electricity. Photovoltaic systems use solar panels to directly convert sunlight into electricity, while CSP systems utilize mirrors or lenses to focus sunlight onto a small area to generate heat, which is then used t produce electricity. As of 2024, solar power generated about 6.9 percent of global electricity. The cost of solar technology has decreased significantly, making it one of the most affordable sources of new electricity. Solar power is a clean and renewable energy source that reduces greenhouse gas emissions compared to fossil fuels. The solar industry creates jobs in manufacturing, installation, and maintenance, contributing to economic development.