Using the information in chapters 10-13 write a brief description of the best system for each of the following situations. Consider factors such as comfort, energy efficiency, cost, maintenance requirements, and efficient space utilization. Be sure to explain why you believe it is the best system.

1. 10,000 square foot open office with 150 work stations. Each station contains a computer with multiple monitors. There are floor to ceiling windows on the south and east walls of the space.

2. A high tech lab that requires precise temperature control in small 10x10 rooms. Each room requires a different temperature and at times may need to modulate from one temperature to another quickly.

3. A university campus with 15 buildings.

4. A high rise apartment building.

5. A single family home being built for an elderly couple living on a fixed income.

FORCED-AIR AIR CONDITIONING SYSTEMS Forced-air air conditioning systems use air as the evaporating medium. Air circu- lates through ductwork to building spaces. Forced-air air conditioning systems are used primarily where the air conditioning equipment is located close to building spaces and where only certain building spaces require cooling. Forced-air air conditioning systems are located close to building spaces because the required ductwork may be fairly large, and it is not practical to run large duetwork over long distances. In large commercial, multistory buildings, the conditioned space may be a building. Each heating unit produce heat for a module or zone of the buildin that requires separate temperature contre a The furnace is the central clementi system that uses air to carry heat. The air is heated and distributed through a building Heating units in modular forced-air heati to control the temperature in the building systems are usually located on roofs. spaces. The major parts of a forced-air heating system are the heating unit, dis- FURNACES forced-air heating system that uses more the furnace, and supply air exits he than one heating unit to produce heat for tally at the other end. Horizontal fu FORCED-AIR HEATING SYSTEMS tribution system, and controls. Different types of forced-air heating systems are used for different applications. The kind forced-air heating system. A furnace of system used for a particular application self-contained heating unit that inclu- depends on the amount of heat required a blower, burner(s) and heat exchangem and the physical layout of the building. electric heating elements, and controls. The two main types of forced-air heating Figure 10-1. Furnaces are available in systems are the central forced-air system ferent sizes and styles for a variety of ap and modular forced-air heating system. cations. Forced-air furnaces are categori by direction of airflow, fuel or enery dimensions, and heating capacity Central Forced-Air Heating Furnaces are categorized base Systems direction of airflow out of the fun, A central forced-air heating system is a The three most common styles of fun forced-air heating system that uses a cen- are upflow, horizontal, and down trally located furnace to produce heat for (counterflow). a building. Supply air ductwork runs from the heating unit to the building spaces. heated air flows upward as it leaves the Return air ductwork runs from the building nace. Return air enters through or new spaces back to the heating unit. An upflow furnace is a furnace in w bottom of the upflow furnace and exi of the top. See Figure 10-2. A hori furnace is a furnace in which heat flows horizontally as it leaves the fu Modular Forced-Air Heating Systems A modular forced-air heating system is a Retum air enters horizontally at one 215 Hydronic Heating Sys STEAM AND HYDRONIC STEAM HEATING SYSTEMS HEATING SYSTEMS A steam heating system is a heating system Most commercial and some residential that uses steam to carry heat from the point buildings use steam or hot water systems of generation to the point of use. Steam heat- to supply the required heat. Boilers located ing systems are used because steam carries in central mechanical rooms supply the more Btu per pound of steam than water, steam or hot water. Water carries one Btu allowing steam to be used where there is a per degree change per pound of water while limited amount of room for the distribution steam carries 970 Btu for every pound of system. Another advantage to steam heating steam that condenses back into a liquid. A systems is that the steam does not need to be heating unit that uses hot water to heat air pumped to the location of use. Steam is a va- allows easier control of the air temperature por that flows any time there is a difference than a steam system. Steam systems rely on in pressure from one area (boiler) to another the difference in pressure to move the steam area (heating unit). The boiler is located in a (vapor) from the boiler through piping to central plant and the steam is distributed to individual heating units where the steam individual buildings of campus complexes gives up the heat as it condenses back into or utility districts. See Figure 11-1. a liquid, and then the condensate is pumped In individual buildings, the boiler is nor- back to the boiler through return piping. In mally located on the lowest floor, usually in a hot water heating system the heated water a basement mechanical room. One of the de- is distributed by a circulating pump through ciding factors in locating the boiler is where supply piping to heating units and returned is the air handing equipment located. If the to the boiler in return piping. air handing equipment is located on several A common practice is to use a combi- floors throughout the building, the boiler is nation of steam and hot water systems to more likely to be located in the basement furnish all the heating and processing needs because the steam will flow up through the of a commercial building. In this type of floors through the supply piping without the system a boiler is used to produce the steam assistance of a pump, and the condensed liq- required by building processes. Some or all uid (condensate) can flow back to the boiler of the steam needed to heat the building is by gravity through the return piping. If all piped to a heat exchanger to heat water of the air handing equipment is located on a The hot water is then circulated through the single floor, the boiler would most likely be heating units by supply and return piping located near that equipment to minimize the to heat building space air. length of piping runs and heat loss. 247 gs, ated systems. The piping system distributes the hot water to building spaces. Terminal devices transfer the heat from the hot water to the air in the building spaces that require heat. A circulating pump moves the water bly HYDRONIC HEATING SYSTEMS ng he A hydronic heating system is a heating sys- he tem that uses water or other fluid to carry or heat from the point of generation to the nal point of use. Hydronic heating systems are ute used where heating equipment is located nd far from building spaces that require heat. he Hydronic heating systems are also used where a central heating plant heats sev- e eral buildings. Hydronic heating systems or consist of a boiler, fittings, accessories, hot |- water supply system, circulating pump, d terminal devices, controls, and hot water return system. See Figure 11-3. A hydronic heating system uses a boiler to heat water and store water. The fittings s maintain the safe and efficient operation of the boiler. Accessories are required to sup- - port the operation of the boiler and associ- - . HYDRONIC AIR CONDITIONING SYSTEMS a A hydronic air conditioning system uses 's water or a solution of water and antifreeze e as the evaporating medium. Terminal de- vices use the evaporating medium to cool air in building spaces. The relatively high specific weight and high specific heat of water make it an excellent evaporating medium. The pipes that carry water in a hydronic air conditioning system are much smaller than ducts that carry air in a forced- air air conditioning system. Hydronic air conditioning systems are used where the air conditioning equipment is located centrally and the building spaces are located remotely. Hydronic air conditioning systems are often located in one central plant that cools several other buildings, such as