Recirculation Drying
A Fluid Bed Dryer/Cooler system typically consist of a combination Dryer and Cooler in one machine. However, sometimes you also have 2 separate machines, and could be a combination of a Rotary Dryer with a Fluid Bed Cooler.
In any case, when you are using a Fluid Bed for Cooling, the discharged air is elevated to normally around 150 to 155 F and sometimes much higher if used in conjunction with a Rotary Dryer. Most Fluid Bed Dryers and Coolers will use approximately the same amount of air for drying as is needed for cooling. In a recirculation system, the baghouse or dust collector must be split, or have a separate section for the drying air which is very wet, and the cooling section, which is dry. The energy saved by reusing this dry clean air from the cooling section (since it must be passed through a dust collector anyway) is expressed in the following formula:
(Tdischarged air - Tambient air) X SCFM cooler fan = btu's saved/hr
An example: The outside air is 45 F and the discharged air off the cooling section is 155 F. You are using 20,000 SCFM in the cooling section and you also use 20,000 scfm in the drying section. How much energy is saved if we recirculated this air from the cooling section?
(155 - 45) X 20,000 = 2,200,000 btu's/hr!
This is 22 therms per hour!
How does that relate to real money or savings: Pick your situation below:
Hours | | Cost per | therm | = savings | per year | | |
per year | Therms Saved | $ 0.80 | $ 0.90 | $ 1.00 | $ 1.10 | $ 1.20 | |
2080 | 45760 | $36,608 | $41,184 | $45,760 | $50,336 | $ 54,912 | |
4160 | 91520 | $73,216 | $82,368 | $91,520 | $100,672 | $109,824 | |
6240 | 137280 | $109,824 | $123,552 | $137,280 | $151,008 | $164,736 | |
8736 | 192192 | $153,753 | $172,972 | $192,192 | $211,411 | $230,630 | |
The energy saved by reusing the energy from the cooling section typically amounts to 10 to 17%, depending on the elevation above sea level of the installation, the type of dryer, along with how cold the outside air gets.
With a recirculated system, the energy usage is typically the same whether it is summer or winter.
Use our Savings Calculator to see your situation and how VENTILEX can GUARANTEE you energy savings.
Standard Drying | Recirculation Drying | Evaporative Cooling |Ventura 130
