HVAC and Electrical Fundamentals - Electricity is usually produced by a generator at a power station and delivered to sub-stations for distribution to homes and businesses. Electricity can also be produced using chemicals like the chemical processes produced in batteries. There is also static electricity which is generally produced from friction and is often times uncontrollable like lightning.
HVAC and Electrical Fundamentals
Either way, electricity is produced; modern society has come to rely on electricity in everyday life. Without electricity, it is fair to say many people in modern society would find life miserable and difficult. Electricity powers our cell phones, lights, refrigerators, air conditioners, heaters, and without electric cars would not be around as electrical energy is needed in the combustion process. The most common ways electricity is generated is the chemical process such as in batteries and generators using magnetism to produce electricity.
HVAC and Electrical Fundamentals - Electrical Flow
Electricity is delivered to its destination via wires (conductors) or in electronics, semiconductors. Electricity is a series of electrons moving through the conductor or semiconductor at a specific potential or pressure which is referred to as voltage or electro-motive force.
HVAC and Electrical Fundamentals - Electrical Delivery
The voltage delivered from power stations generally ranges in the plus 10,000 volts range. It is generated at such a high voltage because it must travel long distances to reach its destination. The destination is usually a sub-station where a step-down transformer steps the voltage down to around 7,500 volts. The sub-station has distribution lines which then feed neighbors, shopping areas, and industrial areas. When the 7,500 volts reaches the neighborhood it encounters another step-down transformer that steps the voltage down again depending on the use. A residential area will have 7,500 volts to 240 volts step down transformers while shopping, commercial, and industrial areas will have 7,500 volts to 480 volts step down transformers.
HVAC and Electrical Fundamentals - Electrical Current
While the voltage is one way of measuring electricity another way of measuring electricity is by measuring electrical current. Electrical current is a measure of the number of electrons flowing through a circuit. If an electric motor is running electrons are flowing through the circuit and this can be measured as current or current is generally referred to as amperage or amp draw in the circuit. If you were measuring current in the circuit with an electric motor and you turned the switch off to the motor the current or amp draw would go to zero. While potential or voltage still exists in the circuit the current is zero with the motor turned off.
Electrical Current, Resistance and Voltage Defined
Think of current and voltage in the form of a faucet at a sink. If you open the faucet the water flows at a certain rate. Say the water flows at 1 gallon per minute. It that was electricity we would call that flow rate amp draw or current. The pressure coming from the faucet would be referred to as voltage. The friction the water encounters from moving through the pipe would be referred to as resistance. Make the pipe smaller with the same pressure (voltage) and the resistance or friction increases.
Make the pipe larger with the same pressure (voltage) and the resistance or friction decreases. Turn the faucet off and you still have pressure (voltage) but no flow or current. The same can be applied to electricity as water flowing from that faucet. Simply compare the flow of the water, the pressure of the water, and resistance of the water pipe to current, voltage, and resistance of the wire and load and you will understand these terms better and how they work in an electrical circuit.
Direct Current (D.C.) and Alternating Current (A.C.)
A direct current circuit has the flow of electrons in one direction and uses only half the sine wave while alternating current flows in both directions in the circuit and uses the full range of the sine wave depending on its frequency or wavelength. Direct current is generally produced by batteries but can be produced by a D.C. generator or a rectifier which converts A.C. to D.C. using diodes. Alternating current is produced by a generator or by converting D.C. to A.C. using a converter. Alternating current in the United States at 60 hertz and most of the rest of the world runs at 50 Hertz. Hertz is a way of measuring the frequency of electricity.
Energy Conservation and HVAC
HVAC Equipment consumes a lot of energy in both the winter and the summer. You can reduce the amount of energy your HVAC equipment uses by purchasing HVAC equipment that is rated for high efficiency and by properly maintaining the equipment. Additionally, you can save energy by installing a programmable thermostat and by sealing any cracks or openings around doors and windows. Adding a layer of insulation to the attic also helps and proper ventilation designed and installed by a professional. Ridge vents, soffit vents, and attic fans also help maintain proper ventilation and reduce the use of energy if designed, controlled and installed properly. It may cost you now but in the future, you will save especially with the ever-increasing costs of energy. Spend a little now and save a lot later.
HVAC and Electrical Fundamentals
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