These two heat exchangers have equivalent duties. The blue one costs less, is easier to install, has a much smaller footprint, responds faster and is easier to clean. Which one should be a candidate for your next expansion or construction? Expansions of building envelopes or of process output is capital intensive, with large demands on…
It is important that your thermal systems respond quickly to control signals, which generally come from thermostats or building automation systems, or from process control systems. Responding slowly can affect your business many ways:
- Excessive energy consumption
- Uncomfortable indoor environment incidents that are slow to correct
- Under- or over-processed products
- Variable quality
Fast-responding heat exchangers transfer their rated heat energy load more rapidly. This means they do their intended job (heating or cooling) faster. For example, if your building automation system is programmed for unoccupied, night-time setback, morning warmup, etc., it will reach its control setpoint faster with plate heat exchangers. The rapid response allows you to fine-tune to shorten the warmup time, for example, which saves energy.
SMALLER MEANS HIGHER EFFICIENCY
Plate heat exchangers are the technology that gives you faster response than conventional shell and tube exchangers. Their thin, corrugated plates transfer heat at a faster rate than thick tube surfaces in shell and tube units. Moreover, the turbulent flow induced across the plates transfers heat faster than the linear flow along the tubes. This accounts for two differences between the two designs:
- Plate heat exchangers are much smaller and lighter than shell and tube exchangers for equivalent duties
- Internal fluid volumes in the plate heat exchangers are much lower
It’s easy to reason that when the steam valve is opened to accommodate a load change, the smaller heat exchanger with the lower internal volume will respond faster than the large one. Also the difference in efficiency across the flow range of the two exchangers is much smaller in the plate heat exchanger. In other words, the shell and tube heat exchanger has a much smaller “sweet spot” of maximum efficiency than does the plate heat exchanger. The plate exchanger has a higher degree of practical efficiency flexibility than does the shell and tube unit.
WHAT THIS MEANS FOR YOUR FACILITY
What this means is that with plate heat exchangers you get:
- Shortest possible time to attain your desired temperature
- Easier control of the temperature setpoint through load swings
- Easier prevention of setpoint overshooting (overshooting or setpoint “hunting” wastes energy)
- The energy you are paying dearly for carries out its intended purposes with less waste
If you have been hearing more complaints about thermal control problems, high energy bills, quality drift, off-grade product, etc., it’s time to ask your engineers about improvements possible by switching to plate heat exchangers. It all begins with a completed Application Data Form (ADF) returned to Tranter. We will give you a conservative model of what order of savings and control improvements you can expect. Any way you run the numbers, plate heat exchangers come out ahead of shell and tube units.