Pub. 5 2015 Issue 3

8 AT THE CENTER OF UTAH INDUSTRY M o st of us take for granted that our homes and places of business can be made comfortable with a simple adjustment of the thermostat. In reality, it is not that simple. A lot goes into the production of the heating and cooling systems that keep us comfortable, and it all begins with mining. In general, most Heating Ven- tilation and Air Conditioning (HVAC) systems consist of two parts: the furnace and the air conditioner. • A gas furnace usually consists of a heat exchanger. It might also have a secondary heat exchanger, depending on how it has been rated for efficiency. There are also blowers for air circulation and the flue draft, a gas control valve, burners, a pilot light or spark ignition, electronic control circuitry, and an external thermostat. • An air conditioner usually consists of four parts: the pump, the evaporator, the condenser, and an expansion valve. There are also two fluids. One is the working fluid, and the other is the opposing fluid medium. Furnace components include the following mining products: • Stainless steel is a metal alloy. Steel is made by mixing iron and carbon. The steel is also mixed with chromium, nickel, molybdenum, silicon, aluminum, and carbon. A coal by-product, coke, is used during the steel-making process. • Aluminized steel is steel that has been coated on both sides with aluminum or an aluminum-silicon alloy. The version with aluminum and silicon is used in heat ex- changers, and the version with pure aluminum is used in air conditioners. • Brass is an alloy. To make it today, the ingredients are usu- ally 67 percent copper and 33 percent zinc. Sometimes lead is added as well in order to improve its machinability. • Copper alloys consist mainly of copper but contain other metals. There are 40 different copper alloys that can gen- erally be found in the U.S. The one that is used depends on the application. The only other difference is the color. As a result, different copper alloys are used for bar, chan- nel, sheet, and tubing. To indicate the one being used, customers ask for it by the color of the metal, the metal’s form, the unified numbering system (UNF) ID number, and the generic name. • Fiberglass is made from silica sand and other ingredients. A fiberglass manufacturer might add aluminum oxide or alumina, calcium oxide or lime, magnesium oxide or mag- nesium, and (sometimes) boron oxide. Fiberglass involves melting the ingredients. The most commonly used method is direct melting. Once melted, the fibers are created by using a bushing with very fine orifices made of a platinum and rhodium alloy. The bushing will have between 200 and 8,000 different orifices. The resulting glass fibers are then coated with a proprietary material, called the size, during a sizing process. Air conditioner components include the following: • Copper or aluminum tubing. Copper tubing has tradition- ally been used for air conditioning and in a furnace’s heat exchangers. • Sheet metal is any metal that has been manufactured into a flat sheet. It includes cold rolled steel and mild steel. They are usually flat or coiled, and are identified by their thickness and their gauge. If a piece of sheet metal is very thin, it is called foil or leaf. If it is thick, it is called plate. • Paint or powder coating. Paint is usually made by combin- ing pigment, resin, solvent, and additives. There are two kinds of pigments, prime and extender. Some of the prime Metals and Mineral Products Used to Make an HVAC