# Calculate the energy in BTUs that is removed

• jason.frost
In summary, the manager of a fried chicken place wants to store a ton of poultry at 0 degrees Fahrenheit, starting at 20 degrees Celsius. The energy in BTUs that is removed during this cooling process can be calculated using the equation Q = cm\DeltaT, where Q is the energy, c is the specific heat, and \DeltaT is the temperature change. The specific heat and latent heat are given as 0.80 BTU/deg F/lb and 99 BTU/lb, respectively. To convert the given values to a consistent system of units, 1 ton is equal to 2000 lbs or 907.184 kg and 1 kW is equal to 3414 BTU. Therefore,
jason.frost
[SOLVED] Heat problem

## Homework Statement

The manager of a fried chicken place wishes to store a ton of poultry at 0 degrees Fahrenheit. Initially the poultry is at 20 degrees Celsius. Calculate the energy in BTUs that is removed in this cooling for storage process.

Assume that the poultry freezes at 32F

Given:
Latent heat: 99 BTU/lb
Specific heats: 0.80 BTU/deg F/lb (above freezing)
0.41 BTU/deg F/lb (below freezing)

## Homework Equations

Was not specifically given any but from the book I'm thinking...

Specific heat
Q = cm$$\Delta$$T

Latent heat
L = $$\frac{|Q|}{m}$$

## The Attempt at a Solution

Would I even have to use anyone of those equations? I am already given the specific heat and latent heat so those should do me no good right?

$$\Delta$$T = 20 - 0 = 20

Q = (.8)(2000)(20)
Q = 32000J

I know I should have to convert all fahrenheit to celcius.

I am really at a loss though what I can use to give me a final BTU. If anyone could give me a push I'd appreciate it. I have no other sources but Internet and the book so other books will not help at this point. Thanks.

jason.frost said:
$$\Delta$$T = 20 - 0 = 20

Q = (.8)(2000)(20)
Q = 32000J

I know I should have to convert all fahrenheit to celcius.
[

Then why don't you? Stick to some consistent set of units.

In the eqn Q = (.8)(2000)(20), where is the 2000 coming from? The 0.8 is in BTU/lb/F, but delta_t = 20...This is meaningless!

Change everything to one system of units.

Whoops...sorry I meant to put in what each letter stood for.

Q = cm$$\Delta$$T
$$\Delta$$T - change in temp
m - mass
c - specific heat (which is given)

1 ton = 2000 lbs = 907.184 kg
kW = Btu / 3414

Q = (.8 BTU/lb/F)(907.184kg)(20C)
Q =

Can I convert the BTUs to kW just by using the equation kW = BTU/3414?

1 ton = 2240 lb = 907 kg.

As I said, convert everything to one system of units. Sp heat is given in BTU. Temp change in C can be easily converted to F. Use whichever you like.

> Can I convert the BTUs to kW just by using the equation kW = BTU/3414?

Yes.

## 1. What is the purpose of calculating the energy in BTUs that is removed?

The purpose of calculating the energy in BTUs that is removed is to understand the amount of energy that is being taken out of a system. This is important in many scientific and engineering applications, such as determining the efficiency of a cooling system or the amount of heat absorbed by a material.

## 2. How do you calculate the energy in BTUs that is removed?

The energy in BTUs that is removed can be calculated by multiplying the mass of the substance being cooled by the specific heat capacity of the substance and the change in temperature. The formula is Q = mcΔT, where Q is the energy in BTUs, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature.

## 3. What units are used to measure energy in this calculation?

In this calculation, the units used to measure energy are BTUs (British Thermal Units). This is a common unit for measuring energy in the US and is equivalent to approximately 1055 joules.

## 4. Are there any other factors that should be considered when calculating the energy in BTUs that is removed?

Yes, there are other factors that should be considered when calculating the energy in BTUs that is removed. These include any losses in the system, such as heat loss due to insulation or inefficiencies in the cooling process. These losses should be taken into account to ensure an accurate calculation of the energy removed.

## 5. What are some real-world applications of calculating the energy in BTUs that is removed?

Calculating the energy in BTUs that is removed has many real-world applications, including determining the energy efficiency of air conditioning systems, refrigerators, and other cooling systems. It is also used in industries such as food processing and chemical manufacturing to determine the amount of heat needed to be removed from a process. Additionally, it is important in understanding the heat transfer process in buildings and designing energy-efficient heating and cooling systems.

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