# Heat Capacity of Air

## What is the Heat Capacity?

This is also known as Thermal Capacity. Heat Capacity is the amount of the heat which can be used to change temperature of a substance by 1°C. In other words we can express this; it is a derivative of the heat of a substance to the temperature of that substance. Its symbol is Q. It may be confused with the specific heat capacity. Thermal Capacity has the same meaning but the specific capacity is different from them.

### What are the Differences between the Heat Capacity and Specific Heat Capacity?

**Heat Capacity **has an extensive feature. This capacity is about per amount but when we talk about the specific capacity; it is about per unit mass. The specific capacity is the heat amount that required to change the temperature of a per unit mass of a substance. SHC has an intensive feature. Thermal capacity is stated as joule per Kelvin. J/K .The specific heat is stated as J/K-KG. (Per kilogram)The Thermal Capacity can be measured by physical. We can state it as quantity. If we explain this situation with some examples:

- 70 grams copper and 100 grams copper have different thermal capacities
- 70 gram copper and 100 gram copper have the same specific heat
- 10 gram zinc and 50 gram zinc have the different thermal capacities
- 10 gram zinc and 50 gram zinc have the same specific heat

These situations are due to the extensive and intensive properties. The thermal capacity is stated with Q while the specific capacity is stated with c. (As symbols)

### The Thermal Capacity of the Air

Air is a gas so there are some differences to find the thermal capacity. The thermal capacity and cooling capacity can be calculated for the air. This is realized through the sl-(specific heat) units. You can use the following formula to find the thermal capacity in the air:

Hs=cp.p.q.dt

Cp is the symbol of the specific heat of the air (1.006 kJ/kg)

P is the air density –(1202 kg/m3)

q is the symbol of the volume flow for air –kg/m3

dt is the symbol of the temperature changes –C°

When you calculate the thermal capacity of the air, you can use this formula to make your transactions easier. In air calculations hs are “sensible heat” and this means thermal capacity of the air.

You can also use the imperial units:

air volume is stated as cfm

dt is stated as F°

Hs is stated as btu/hr

### How to Calculate Thermal Capacity?

It is easy to calculate the thermal capacity with a simple thermal capacity formula. You can review the thermal capacity formula:

Q=m.c.▲t

Q is the symbol of the thermal capacity

m is the symbol of the mass of the substance-g

c is the symbol of the specific heat

▲t is the symbol of the temperature change C°

An example: A 130 gram copper is heated from 25 C° to 35 C° .The specific heat is 387 J/kg .C°

In order to find the; Q= 130. 0.387 J/g. 10 The **Heat Capacity** is equal to 503.1 J