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Heat Transfer Equipment
- Introduction to Heat Transfer
- Types of Heat Transfer
- How Heat Transfer Equipment works
- Features of Heat Transfer Systems
- Maintenance of Heat Transfer Systems
What is Heat Transfer?
In the most basic terms, heat transfer is comprised of two components: flow of heat and temperature. The flow of heat represents the movement of energy from one place to another and temperature is the measure of thermal energy available. Thermal energy is also known as kinetic energy, or energy in motion. We will focus on fluid heat exchangers, since that is what we at Cooling Technology, Inc specialize in.
Types of Heat Transfer Mechanisms
There are three primary mechanisms for heat transfer: (1) conduction, (2) convection, and (3) radiation. Conduction is the heat transferred through matter by communicating of energy with no displacement to the particles involved. Convection is the circulatory movement that occurs at a non – uniform temperature due to a variation in density. Radiation is the process of emission, transmission, and absorption of radial energy. (all definitions courtesy of http://www.merriamwebster.com/).
In a fluid heat transfer system the fluids may be separated by a solid wall so they never mix or the fluids may be directly contacted. Heat exchangers are categorized by their flow arrangement: parallel flow, cross flow, or counter flow. In parallel flow heat transfer equipment the two fluids enter an exchanger on one end and travel parallel to each other until they reach the other end. In cross flow heat exchangers, the fluids travel perpendicular to each other, and in counter flow heat transfer systems the fluids begin at opposite ends and travel towards each other.
How Heat Transfer Equipment Works:
The most basic concept for a heat exchanger is to maximize the surface area of a wall between two fluids while at the same time minimizing the resistance to the flowing motion of a fluid through the exchanger.
Two primary pieces of equipment used are condensers and evaporators. Condensers cool refrigerant vapor back to a liquid state in their refrigerant cycles. Evaporators heat a liquid to a boil so the liquid changes to a vapor.
Fluid heat transfer systems circulate thermal fluid through process equipment to maintain an even consistent temperature. Tanks, pipes, pumps, and heating and/or cooling systems are used to circulate water, steam, hydrocarbon oils, and glycols. Heat sources include electricity, natural gas, propane, fuel oil, and solar power. Cooling sources primarily use air and water. Glycols are added to water to prevent freezing in process temperatures below 32°F.
The most common type of heat transfer equipment is a shell and tube exchanger which consists of a series of small tubes with the fluid flowing through these tubes. The other liquid runs over these inner tubes while encased in a larger shell.
Brazed Plate and Plate & Frame heat exchangers are another type which direct the flow through a waffled surface area. The fluids are separated by plates. This heat exchanger can be more efficient than a shell and tube heat transfer system.
Contact Cooling Technology, Inc and one of our technical engineers will help you design a heat transfer system to meet your custom needs.
Features of Heat Transfer Systems
Features may be very varied on heat transfer systems. Some heat transfer systems have local panels and gauges for measuring pressure and temperature whereas others have the ability for us to remotely monitor. Emergency alarms to denote high pressures and low coolant levels and safety relief valves are all available on Cooling Technology, Inc’s heat transfer equipment. Stainless steel cabinetry and nonferrous water path constructions are also available. A Cooling Technology, Inc. representative will be happy to work with you to determine which will best fit your requirements for a heat transfer system.
Maintenance for Heat Exchangers
Evaporators and condensers need proper maintenance to ensure they are performing at an optimum level. If these items are not properly maintained, some serious issues could occur. Fouling occurs when man made impurities enter and build up, which decrease the heat transfer coefficient. Scaling occurs when impurities which are found naturally (such as calcium or magnesium) build up. These two problems are very manageable as long as they are detected early enough, so it is important to have your systems cleaned every other year. Contact one of Cooling Technology, Inc Sales Representatives to learn more about our maintenance plans available to you.