Heat

Question 1

The quantity of heat required to raise the temperature of one pound (.4kg) of water 1d F.

Answer 1

British Thermal Unit (Btu)

Question 2

A unit of heat equal to 100,000 BTU

Answer 2

Therm

Question 3

The base SI unit of temperature equal to 1/273.16 of the triple point of water.

Answer 3

Kelvin / K

Question 4

The particular temperature and pressure at which the liquid, gaseous, and solid phases of a substances can exist in equilibrium.

Answer 4

Triple Point

Question 5

A unit of heat equal to the quantity of heat required to raise the temperature of one gram of water 1dC at a pressure of one atmosphere, equivalent to 4.186 joules.

Answer 5

Calorie, Gram Calorie, Small Calorie

Question 6

A temperature scale in which 32dF represents the freezing point and 212dF the boiliding point of water under standard atmospheric pressure.

Answer 6

Fahreinheit Scale

when you know degrees Celsius, first mltiply by 9/5 and then add 32 to find degrees Fahrenheit.

Question 7

A temperature scale divided into 100 degrees, in which 0dC represents the freezing point and 100dC the boiling point of water under standard atmospheric pressure.

Answer 7

Celsius Scale or Centigrade Scale

When you know degrees Fahrenheit first subtract 32 and then multiply by 5/9 to find degrees Celsius.

Question 8

An absolute scale of temperature having a zero point of -273.16dC.

Answer 8

Kelvin Scale

Question 9

The hypothetical lowest limit of physical temperature characterized by complete absence of heat, equal to -273.16dC or -459dF.

Answer 9

Absolute Zero

Question 10

Temperature as measured on an absolute scale.

Answer 10

Absolute Temperature

Question 11

The quantity of heat required to raise the temperature of a substance by one degree,

Answer 11

Heat Capacity

Question 12

Heat capacity per unit mass of a substance: the number of Btu required to raise the temperature of one pound of a substance 1dF, or the number of calories per gram per degree centigrade.

Answer 12

Specific Heat

Question 13

The quantity of heat absorbed or released by a substance during a change in phase at constant temperature and pressure.

Answer 13

Latent Heat

Question 14

The quantity of heat absorbed or released by a substance during a change in temperature without a change in phase.

Answer 14

Sensible Heat

Question 15

These units of temperature measurement are important to determine the state of humid air.

Answer 15

Dry Bulb, Wet Bulb, and Dew Point temperatures are all needed to determine the state of humid air. Knowledge of only two of these values is not enough to determine the state - including the content of water vapor and the sensible and latent energy (enthalpy).

Question 16

What is air enthalpy?

Answer 16

This is the amount of internal energy within a system combined with the product of its pressure and volume. In the HVAC industry, the process is assumed to be at a constant pressure and, as such, the change in enthalpy is equal to the heat absorbed or released.

Question 17

What is Dry Bulb Temperature?

Answer 17

This temperature, usually referred to as air temperature, is the air property that is most commonly used. It refers to the ambient air temperature. This temperature is not affected by the moisture of the air. It is an indicator of heat content and is shown along the bottom axis of the psychrometric chart. Constant temperatures of this type appear as vertical lines in the psychrometric chart.

Question 18

What is Wet Bulb Temperature?

Answer 18

The temperature is the temperature of adiabatic saturation. it is indicated by a moistened thermometer bulb exposed to air flow. The adiabatic evaporation of water from the thermometer and the cooling effect is indicated by this temperature being lower than that of the dry bulb temperature in the air.

combining this with the dry bulb temperature on a psychrometric diagram or Mollier chart gives the state of the humid air.

Question 19

What is Dew Point temperature?

Answer 19

This is the temperature at which water vapor starts to condense out of the air, the temperature at which air becomes completely saturated.

If this temperature is close to the air temperature, the relative humidity is high, if it is well below the air temperature, the relative humidity is low.