HVAC Basics

Air Conditioners: How Does It Work?

An air conditioner cleans, circulates, cools and dehumidifies (removes undesirable moisture from) indoor air. A filter cleans the air by trapping dust and other small particles. An air handler (blower built into the system) circulates it, while the cooling and dehumidifying are accomplished by a process called refrigeration.

Refrigeration

Refrigeration cools a home by transferring heat inside a home to the outdoors. All central air conditioners employ two main units in this process – the indoor unit and the condensing unit.

Indoor Unit

This unit removes undesirable indoor warmth and humidity. It includes the filter, the air handler, and the evaporator coil. The air handler blows filtered air through the evaporator coil. The evaporator coil is kept cold by the circulation of a substance called a refrigerant. Air that travels through the evaporator coil gives up heat (the colder coil absorbs it) and humidity (moisture condenses upon contact with the cold surface of the coil). The cooler, drier air that continues through the air ducts is vented throughout your home to maintain your desired comfort level. Depending on the structure of your home, the ductwork may be above the ceiling or below the floor.

Condensing Unit

Outdoors, at the condensing unit, an air conditioner releases the heat that was captured indoors. The same refrigerant that absorbed the heat indoors at low pressure is now pressurized by the compressor and is circulated through another coil, the condensing coil. In the condensing coil, under high pressure, the refrigerant releases its heat very quickly, making the coil itself hot. A fan blows across the coil, cooling its temperature down and transferring the heat to the outside air.

Furnace: How Does it Work?

The furnace is the most important component of a central heating system. It houses all the working parts. So when you replace the furnace, you replace the vital operating parts of your heating system. It is by choosing from among the different models and brands of furnaces available that you determine the quality and cost of your business’s heating for years to come.

Furnace

The Furnace is part of a forced-air system. Warm air is forced or blown, through a system of air ducts to each of the rooms in the office. Office air drawn into the furnace passes through a filter, where dust and other small particles are trapped. A blower unit blows the filtered air through the furnace, and the air absorbs heat.

Gas Heat

If it is a gas furnace, the heat is supplied by the burning of natural gas. A mixture of gas and air flow into the burner and is ignited by the pilot. Combustion occurs, and warm air from the burner flame rises to fill a chamber known as a heat exchanger. The heat exchanger becomes hot. Office air passing around the heat exchanger absorbs that warmth, continues into the air ducts and the heat is distributed through the business.The by-products of combustion pass upward through a venting system and escape through a vent in the roof.

Electric Heat

If the furnace is electric, heat is generated by an electric heating element. Electric current traveling through the element creates heat. By the heat transfer processes called conduction and convection, heat is transferred into the air stream and flows through the air ducts into the rooms of the business.

Thermostat

Whether you heat your office with gas or electricity, a wall thermostat will be installed. This measures room temperature and turns the central heating system off or on as the temperature rises or falls to designated levels. Careful location of the thermostat is an essential consideration in maintaining maximum comfort levels in your business.