Savings Available in Cold Regions
When you install Ecogate, you get straightforward savings from your electricity bill. However, in cold regions, we have ways to help you save even more!
Returned Air Heating Savings Calculation
This is an example from a woodworking factory with a 150 HP fan used for dust collection for 30 workstations in Winnipeg, Canada, where winter temperatures are low. Natural gas is used for heating during the winter months.
The main duct is connected to the dust collector installed just outside the factory; i.e. the exhaust air travels to the dust collector and is returned to the factory interior. The duct system and dust collector itself are not insulated, therefore the air is cooling down as it travels outside. The gas heating system will compensate for this cooling.
We recorded measurements in March:
The average temperature outside was - 8 F (-22 C)
The average temperature inside the factory was 67.6 F (20 C).
The returned air temperature was 52.6 F (11 C).
As you can see, the temperature dropped by running air outside the building was 15 F (9 C).
Without the Ecogate system, the air volume traveling through the dust collector outside the building was 26,825 CFM (cubic feet per minute), while with the Ecogate on-demand ventilation system, this air volume was reduced by 68% i.e. to 8,584 CFM. The gas heating now needs to heat only 8,584 CFM instead of 26,825 CFM - a significant reduction by 18,241 CFM.
Recordings with Ecogate
To calculate how much a factory will save during a heating season from October to March requires knowledge of average temperatures during this time. Combined with the above return air volume reduction, Manitoba Hydro calculated that natural gas savings are $4,460 per year.
Winter Anti Freezing Mode Savings
This factory operates 14 hours per day, five days per week. During the freezing season from October to March they need to keep moving air through the dust collector filters in order to protect them from freezing (freezing makes filter bags non-functional). It means anti-freezing fan operation must run 10 hours a day Monday to Friday, and 48 hours during the weekend. From October till the end of March this represents 2,352 hours of fan anti-freezing operation. Without Ecogate, this fan was running at full speed (60 Hz) at a consumption of 97 kW (130 HP). This represents 228,144 kWh of electricity, and even at a low electricity cost of $0.06 per kWh, this costs $13,689 per year.
With the Ecogate Winter Mode kit, the fan is operated at 20 Hz (instead of full speed 60 Hz) and triggered automatically only when the temperature outside is under 39 F (4 C). Based on the fan law, the consumption of the fan at 20 Hz is just 6.2 kW (8.4 HP), therefore consumption per winter mode is 14,583 kWh, and electricity cost is now only $875, a reduction by $12,814.
Fan Operation Savings
This factory also benefits from the reduction of fan operating cost: without Ecogate, the dust collecting fan is consuming 97 kW 3,528 hours per year, this represents a consumption of 342,216 kWh per year. At $0.06 per kWh, the electricity cost is $20,533. With Ecogate, the fan consumption is reduced to 31 kW, therefore the consumption per year is 109,368 kWh per year at an electricity cost of $6,562. The electricity savings on fan operation is $13,970.
Summary of Savings with Ecogate System
Here is a summary of savings on fan operation + on winter heating by return air reduction + on winter filter anti freezing operation = $13,970 + $12,814 + $4,460 = $31,245 per year.
If your system is smaller or larger compared to a 150 HP system in this example, your savings will be smaller or higher. If winter temperatures in your location are not this low, your winter savings will be lower.
Similar or higher savings by reduction of return air volume are achieved if for example pharmaceutical or chemical production is using air-conditioning of the makeup air during winter and during summer.
Author: Ales Litomisky