How do you calculate the number of tubes in tube and shell heat exchanger?
The main basic Heat Exchanger equation is:
- Q = U x A x ΔTm = The log mean temperature difference ΔTm is:
- ΔTm = (T1 – t2) – (T2 – t1)
- = °F. Where:
- T1 = Inlet tube side fluid temperature; t2 = Outlet shell side fluid temperature;
- ln (T1 – t2) (T2 – t1)
How do you calculate the number of passes on a heat exchanger?
The number of passes in a heat exchanger is generally determined by the total flow of tube side fluid, the exchanger area requirement, allowable pressure drop and any limitations in tube length (location, access, bundle pulling requirements, etc).
How do you calculate the overall heat transfer coefficient for shell-and-tube heat exchanger?
We can use the following equation to get the overall heat transfer coefficient for a shell & tube exchanger. Note, this overall heat transfer coefficient is calculated based on the outer tube surface area (Ao). So it must be multiplied by the Ao value for using in the overall heat transfer equation.
How do you calculate tube pitch in heat exchanger?
TEMA standards recommends a minimum tube pitch of 1.25 * Tube outer diameter for triangular pitch. For example, if we have a tube outer diameter of 12.7 mm (0.5 inch) then the recommended tube pitch for triangular pitch arrangement is: 1.25 * 12.7 mm = 16 mm (0.6 inch).
What is baffle pitch?
The spacing between segmental baffles is called the baffle pitch. The baffle pitch and the baffle cut determine the cross flow velocity and hence the rate of heat transfer and the pressure drop.
What is baffle cut percentage?
Baffle is provided with a cut (%) which is expressed as the percentage of the segment height to shell inside diameter. In general, baffle cut can vary between 15% and 45% of the shell inside diameter. This cut allows the fluid to pass through in parallel or counter flow direction.
What is the purpose of a baffle?
The main roles of a baffle in a shell and tube heat exchanger are to: Hold tubes in position (preventing sagging), both in production and operation. Prevent the effects of steam starvation, which is increased with both fluid velocity and the length of the exchanger. Direct shell-side fluid flow along tube field.
How are baffle cuts calculated?
l c = baffle cut = distance from the baffle to the inside of the shell, mm or in.
What is fouling factor?
The fouling factor represents the theoretical resistance to heat flow due to a build-up of a layer of dirt or other fouling substance on the tube surfaces of the heat exchanger, but they are often overstated by the end user in an attempt to minimise the frequency of cleaning. …
What is pressure drop pipe?
Simply put, pressure drop is the difference in total pressure between two points in a fluid-carrying network. When a liquid material enters one end of a piping system, and leaves the other, pressure drop, or pressure loss, will occur.
How do you calculate condenser capacity?
– The formula for the capacity of condenser is given by C=Ad When A is the area of each plate and d is the distance between the plates.
What is condenser capacity?
The condenser capacity is the ability of the condenser to transfer heat from the hot vapour refrigerant to the condensing medium. The heat transfer capacity of a condenser greatly depends upon the temperature difference between the condensing medium and the vapour refrigerant.
How do I choose a condenser?
Be sure to select condensing units that feed with the same voltage and frequency of the power supply. Also analyze the starting torque. In systems using the expansion valve (instead of capillary tube) you must pay attention if the compressor is in the condensing unit has a high starting torque.
What is the meaning of heat rejection ratio of a condenser?
HRF = This ratio gives the heat rejected in the Condenser per unit load of Refrigeration handled by the Evaporator. In other words, when we say that HRF is 1.2, it means that for every tonne of refrigeration load handled by the evaporator, the condenser will have to reject heat equivalent to 1.2 tonne.
How much heat is rejected in the condenser?
Air cooled condensers normally requires between 125°F to 130°F condensing temperature to reject heat to a 100° ambient, while a water cooled condenser can operate at 105°F condensing temperature and reject its heat to a 95°F water stream.
How do you find the heat of rejection?
So…at design…the total heat of rejection (THR) is the sum of the compressor capacity plus the motor power input expressed in Btu/hr. The energy in equals the energy out.
What is heat Rejector tint?
Heat rejection film, commonly known as Ceramic window tint in the industry, is the newest wave in window tinting films for cars that are designed to keep you comfortable, cool, and keep your car in great shape. Let’s take a closer look at 3 ways heat rejection will help keep you and your vehicle cool all summer long.
What is work and heat?
Heat and work are two different ways of transferring energy from one system to another. The the distinction between Heat and Work is important in the field of thermodynamics. Heat is the transfer of thermal energy between systems, while work is the transfer of mechanical energy between two systems.
What is the refrigeration effect?
Refrigerating Effect. This is the heat absorbed in the evaporator per lb of refrigerant. It is determined by the difference in enthalpy of a lb or refrigerant vapor leaving the evaporator and that of a lb of liquid just upstream (ahead) of the expansion valve at the evaporator.
What is COP in refrigeration?
COP stands for Coefficient Of Performance and indicates the efficiency of heating and cooling machines. The COP is defined by the ratio heat dissipation and electrical power intake.
Is a higher COP better?
Higher COPs equate to lower operating costs. The COP usually exceeds 1, especially in heat pumps, because, instead of just converting work to heat (which, if 100% efficient, would be a COP of 1), it pumps additional heat from a heat source to where the heat is required.