May 26, 2016 · 73-6) Explain how to measure airflow using temperature rise. Measure the system temperature rise. Look up the system Btuh output capacity. Use the formula CFM = Btuh / …
Explain how to measure airflow using temperature rise. CFM = (Input BTU x thermal efficiency) / (1.08 x DT) How do the TAB procedures for a zoned system differ from a nonzoned system? Procedures for a zone system and non zoning is also most similar except to each zone of zoned system to get correct air flow the zone dampers are to be adjusted.
Temperature rise is the temperature difference between the entering and leaving air. To measure airflow using the temperature rise formula: For electric strips, BTU/hr=Volts x Amps x 3.41 For gas furnaces, BTU/hr = gas firing rate in ft3/hr × heat content in BTU/ft3 × combustion efficiency expressed as a decimal Measure Temperature Rise :Leaving air temp - entering air temp = …
May 26, 2016 · 73-3) Outline the general test and balance procedure for system airflow. • collect complete information • examine the entire installation • open all dampers • operate the system • measure the airflow at the blower using temperature rise or pressure drop • compare system airflow to design airflow • adjust system airflow to achieve design airflow • measure the airflow …
A thermoresistor is a little electronic piece that conducts electricity when heated. The more electricity conducted, the higher the temperature reading. Two more facts and we'll move on. First of all, there is no such thing as a cold particle -- being cold only means that there is an absence of kinetic energy.
A thermometer is a clever device for measuring the average kinetic energy of a system. Glass thermometers contain a liquid that expands when it is warmed and contracts when it is cooled.
Nikki has a master's degree in teaching chemistry and has taught high school chemistry, biology and astronomy. In this lesson, discover what temperature is a measurement of while learning how to properly measure temperature in a lab. Learn about the important instruments needed for this essential lab skill. Create an account.
Fevers happen when the body elevates its own temperature above 98.6 degrees Fahrenheit to try to cook out any germs that are making it sick. So the best way to determine if you have a fever is to take your temperature!
If you rush back inside and sit by the fire, the kinetic energy from the fire will transfer back to you, the relatively cool object in the room. The transfer of energy continues until an equilibrium is reached and both objects have the same average kinetic energy. The same thing happens when we use a thermometer.
Zero degrees Celsius equals the freezing point of water. The freezing point of water in Kelvin, however, is 273.15. If you need to convert between Kelvin and Celsius remember this simple formula: temperature in Kelvin equals degrees Celsius plus 273.15. K = °C + 273.15.
The formula that converts between Fahrenheit and Celsius is quite complicated: F = C (9/5) + 32.
A few basic principles go a long way toward explaining how and why air moves: Warm air rising creates a low pressure zone at the ground. Air from the surrounding area is sucked into the space left by the rising air. Air flows horizontally at top of the troposphere; horizontal flow is called advection. The air cools until it descends. Where it reaches the ground, it creates a high pressure zone. Air flowing from areas of high pressure to low pressure creates winds. Warm air can hold more moisture than cold air. Air moving at the bases of the three major convection cells in each hemisphere north and south of the equator creates the global wind belts.
Because more solar energy hits the equator , the air warms and forms a low pressure zone. At the top of the troposphere, half moves toward the North Pole and half toward the South Pole. As it moves along the top of the troposphere it cools. The cool air is dense and when it reaches a high pressure zone it sinks to the ground. The air is sucked back toward the low pressure at the equator. This describes the convection cells north and south of the equator.
If the Earth did not rotate, there would be one convection cell in the northern hemisphere and one in the southern with the rising air at the equator and the sinking air at each pole. But because the planet does rotate, the situation is more complicated.
Since water has a very high specific heat, it maintains its temperature well. So water heats and cools more slowly than land. If there is a large temperature difference between the surface of the sea (or a large lake) and the land next to it, high and low pressure regions form. This creates local winds.
Monsoon winds are larger scale versions of land and sea breezes; they blow from the sea onto the land in summer and from the land onto the sea in winter. Monsoon winds are occur where very hot summer lands are next to the sea. Thunderstorms are common during monsoons ( Figure below ).
During the day, air on mountain slopes is heated more than air at the same elevation over an adjacent valley. As the day progresses, warm air rises and draws the cool air up from the valley, creating a valley breeze. At night the mountain slopes cool more quickly than the nearby valley, which causes a mountain breeze to flow downhill.
Chinook winds (or Foehn winds) develop when air is forced up over a mountain range. This takes place, for example, when the westerly winds bring air from the Pacific Ocean over the Sierra Nevada Mountains in California. As the relatively warm, moist air rises over the windward side of the mountains, it cools and contracts. If the air is humid, it may form clouds and drop rain or snow. When the air sinks on the leeward side of the mountains, it forms a high pressure zone. The windward side of a mountain range is the side that receives the wind; the leeward side is the side where air sinks.
Heat, , is thermal energy transferred from a hotter system to a cooler system that are in contact.
What contains more heat, a cup of coffee or a glass of iced tea? In chemistry class, that would be a trick question (sorry!). In thermodynamics, heat has a very specific meaning that is different from how we might use the word in everyday speech.
Heat and temperature are two different but closely related concepts. Note that they have different units: temperature typically has units of degrees Celsius () or Kelvin ( ), and heat has units of energy, Joules ( ). Temperature is a measure of the average kinetic energy of the atoms or molecules in the system.
The zeroth law of thermodynamics defines thermal equilibrium within an isolated system. The zeroth law says when two objects at thermal equilibrium are in contact, there is no net heat transfer between the objects; therefore, they are the same temperature.
How can we measure heat? Here are some things we know about heat so far:
We can use the heat capacity to determine the heat released or absorbed by a material using the following formula:
Let's say that we have of hot tea which we would like to cool down before we try to drink it. The tea is currently at , and we'd like to cool it down to . How much thermal energy has to be transferred from the tea to the surroundings to cool the tea?