Heat exchanger
Typically, heat exchangers are used to allow heat from liquids or gases to pass to other liquids or gases, without the two coming into direct contact. Essentially they transfer the heat without transferring the fluid that carries the heat.
Heat exchangers are often used as part of heating, cooling or heat recovery systems.
Heat exchange devices can be used in a number of processes, including:
- Air conditioning systems.
- Radiators.
- Refrigeration.
- Heat pumps.
- Heat recovery ventilation.
- Waste water treatment.
- Nuclear and power plants.
- Machinery and engines.
- Specialist energy-saving devices such as energy-efficient showers.
The two most common types of heat exchangers are the 'shell and tube' and 'plate' or 'fin':
- In shell and tube heat exchangers, one fluid flows through a series of metal tubes within a sealed unit while another fluid passes between the tubes. The two fluids can flow in the same direction which is called parallel flow, in opposite directions, known as counter flow or counter current, or they can flow at right angles, known as cross flow.
- Plate or fin heat exchangers consist of metal fins with large surface areas that air passes around. This more open construction can allow easier inspection, cleaning and disassembly. This system is often used for chilled beams or integrated service modules.
Variations on these basic types include; plate heat exchangers, double pipe heat exchangers, pillow heat exchangers and so on.
Earth-to-air heat exchangers draw ventilation supply air through buried ducts or tubes. As the temperature of the ground below 3m is practically constant, it substantially reduces ambient air temperature fluctuations and can provide space conditioning throughout the year, with the incoming air being heated in the winter and cooled in the summer.
The appropriate heat exchanger can be selected by consideration of:
- Space availability.
- The heat carrying mediums.
- Fluid flow capacity.
- Pressure limits.
- Temperature ranges.
- Thermal performance requirements.
- Requirements for maintenance and repair.
[edit] Related articles on Designing Buildings
- Absorption heat pump.
- Air conditioning.
- Air source heat pumps.
- Chilled beams.
- Coefficient of Performance CoP.
- Earth-to-air heat exchangers.
- Geothermal pile foundations.
- Ground energy options.
- Ground source heat pumps.
- Heat pump.
- Heat recovery.
- Integrated service module.
- Plate heat exchanger.
- Refrigeration.
- Thermal labyrinths.
- Waste heat.
- Water source heat pumps.
Featured articles and news
The benefits of writing articles for your organisation
How to create a profile for your organisation and publish for free.
No Falls Week. The importance of safe working at height
What to expect and what is on offer to avoid accidents.
Scottish Government action to reach net-zero targets
Retrofit expert group highlight critical actions needed.
A forward thinking, inclusive global community of members.
From engineered product life-spans, to their extension.
Circular economy in the built environment
A brief description from 2021. Where are we now?
Mental Health Awareness Week with ABS
Architects Benevolent Society programme of activity.
CLC publishes domestic retrofit competency framework
Roadmap of Skills for net zero.
May 13-19: Moving more for our mental health.
Understanding is key to conservation.
Open industry engagement survey seeks responses
Institutions and the importance of engagement.
National Retrofit Hub unveils new guide
Digital Building Logbooks and Retrofit: An Introduction.
Enhancing construction site reporting efficiency
Through digitisation and the digital revolution.
Noise in the built environment
BSRIA guide TG 20/2021.
17,000 people suffer conditions as a result of exposure to excessive noise at work.
Turning down the noise: Auditory health
A pervasive risk with far-reaching consequences.
Getting the most out of heat pumps and heating
How heat pumps work and how they work best.
Electrotechnical excellence, now open for entries.