CANADEL, of Louiseville, Quebec, designs and manufactures wood furniture in a wide variety of styles, colors and finishes. Using a new intelligent ventilation control system in its paint shops generates substantial energy savings.
Finishing involves the application of stain and clear coat in paint booths. To ensure air quality, each booth has its own ventilation system. Evacuated air must be replaced by air from the outside, which must of course be heated to shop temperature. Until recently, control of the ventilation system was on/off: the paint booth operator turned the fan on at full power at the beginning of his shift, and turned it off only at the end. Because painting takes place only 30-40% of the time rather than continuously, this resulted in significant energy waste in driving the fan and, more importantly, for heating the make-up air.
NOVEO Technologies of Montreal has developed an innovative ventilation controller, which generates energy savings. A high efficiency motor whose speed is modulated by a frequency controller drives the fan. The fan starts only when the operator activates his paint gun. The fan then runs at full speed until the paint gun stops. Fan speed then decreases stepwise to zero, so long as painting has not resumed. Speed percentages and time delays are fully programmable. Furthermore, a volatile organic compound (VOC) sensor triggers the fan and modulates its flow rate if concentration rises above a threshold value.
By evacuating only when necessary, the controller decreases the evacuated volume, and thereby the natural gas consumption required to heat the make-up air.
Communication between Canadel’s building management system and the controllers is via the BACnet protocol, using the controller’s integrated communication ports.
Canadel installed the first controller in December 2005 and, building on the success obtained, continued in 2006 with general implementation on its 56 paint booths.
NOVEO Technologies Inc., with the financial assistance of Gaz Métro and the Industry Energy Research and Development (IERD) Program of Natural Resources Canada, mandated Natural Gas Technologies Centre (NGTC) to evaluate the energy savings obtained through use of its controllers.
NGTC took measurements over two days on a typical application. Flow rate was measured by a Pitot probe calibrated by a hot wire anemometer. Power was measured by a hook-on ammeter. During the first day, the paint booth operated as before installation of the NOVEO-AIRTM controller, which means that it was in manual mode with the fan continuously on (Figure 2a). During the second day, the controller was activated and the data of Figure 2b were collected.
Comparison of energy consumption was based on 250 days/year operation, 9.5 hours per day, and 4,992° C-days per year in Louiseville (Environment Canada: Canadian Climate Normals). We assumed that incremental electricity consumption and incremental power demand of the make-up air unit were equal to those of the paint booth fan. Unit costs were $0.56/m3 of natural gas, 4.2¢/kWh of electric energy consumption and $13.08/kW per month for power demand.
Table 1: Annual savings obtained with the NOVEO-AIR™
for a 2.2 kW (3 HP) paint booth
| Consumption related to paint booth ventilation | With continuous ventilation | With NOVEO-AIR™ | Absolute saving | Relative saving |
| Make-up air heating, m3 of natural gas (Cost) | 12,254 $6,862 |
4,848 $2,715 |
7,406 $4,147 |
60.4% |
| Electrical energy, kWh1 (Cost) | 8,02 $337 |
2,992 $126 |
5,028 $211 |
62.7% |
| Power demand, kW2 (Cost) | 3.38 $530 |
1.72 $269 |
1.66 $261 |
49.2% |
| TOTAL energy, GJ (Cost) | 489.0 $7,729 |
192.8 $3,109 |
296.2 $4,619 |
60.6% 59.8% |
1 For evacuation and make-up air.
2 Monthly maximum for the evacuation and make-up air.
The energy savings identified in Table 1 show the effectiveness of the controller and its value as an industrial innovation. Payback of a typical investment is between 1 year and 2 years.
For Canadel, the impact of the reduction in energy consumption is very significant. By sampling data from all installed controllers, we estimated annual savings of $272,500 for the plant as a whole.
Energy savings:
- Are higher in a colder climate;
- Increase with the intensity of usage of the plant;
- Are greater in a higher-powered paint booth.
For operators, the new system improves comfort by reducing noise level, which was measured to be 71.6 dBA with the fan off vs. 81.5 dBA with the fan at full speed.
J. F. Bond, Eng.,
Research Engineer,
Natural Gas Technology Centre
Richard Béraud, Eng.
Principal Adviser
DATECH Group
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