Top 5 Applications of Energy Equations in Thermodynamics | Thermodynamics

The following points highlight the major five applications of energy equations in thermodynamics. The applications are: 1. Boiler 2. Turbine (Engine)/Compressor (or Pump) 3. Throttling Process 4. Nozzle 5. Condenser.

Application # 1. Boiler:

It is a steam generator.

Characteristics of the boiler are:

(1) Change in velocity of the fluid at the entrance and exit is very small, and hence ΔKE can be neglected, i.e., ΔKE = 0

(2) Change in elevation between the inlet and exit point is very small so change in PE may be neglected, i.e., ΔPE = 0

(3) Since no work is done in a boiler w = 0

∴ From SFEE on mass basis,

 

Application # 2. Turbine (Engine)/Compressor (or Pump):

The turbines and engines are power producing devices whereas Compressors, Pumps, Blowers etc. are power consuming devices.

Characteristic of a turbine are:

(i) Since it is insulated, negligible heat transfer.

∴ q = 0

(ii) Change in velocity of the fluid at the entrance and at the exit is negligible.

∴ ΔKE = 0

(iii) Since change in elevation between inlet and exit point is negligible,

 

Here work is produced at the expense of enthalpy. Similarly for an Adiabatic Pump/Compressor, work is done on the system, so w is -ve.

∴ SFEE becomes, w = h₂ – h₁ (since w is – ve)

Application # 3. Throttling Process:

When a fluid flows through a partially opened valve or an orifice then there is an appreciable pressure drop and the flow is said to be throttled.

Characteristics are:

(i) q = 0,

(ii) w= 0,

(iii) ΔPE = 0

Substituting these in SFEE we get –

Application # 4. Nozzle:

It is a device which is used to increase the KE of flowing fluids –

(i) q = 0

(ii) w = 0

(iii) ΔPE = 0

∴ Substituting these in SFEE we get,

 

Application # 5. Condenser:

Condenser or to show in a steady flow process with multiple streams of fluid without mixing.

In this case, cooling water enters at section 1–1’ passes through the tubes and leaves the condenser at section 2–2’

Steam to be condensed enters the condenser at Section 3-3 and when it comes in contact with the cold surface of water tubes, it gets condensed and the condensate leaves the condenser at Section 4-4′.

So, in this case working fluids are water and steam i.e., two fluids flow through the system and since they do not mix with each other, it may be considered as a steady flow system with multiple streams of fluid without mixing.