How to Reduce Costs & Emissions with Dewatering Bore Pumps
As a business operator, you understand how important it is to find ways to reduce your expenditure while keeping the same level of productivity. According to the Australian Government Department of the Environment & Energy, ‘pumping systems account for nearly 20% of the world’s energy use’. Therefore, increasing the efficiency of your pumping systems benefits both your business and corporate social responsibility.
Dewatering bore pumps can be amazingly robust pieces of equipment, however your system alone is not enough to reduce energy demands. To help solve this problem, we’ve compiled a handy list of ways you can reduce both your costs and emissions.
Use the right equipment
When choosing the right dewatering pump for your site, it can often be tempting to go with the most cost-effective option. However, it is important to recognise that this initial saving can become a false economy if your pump does not perform correctly. Therefore, if you are looking at the capital costs that come with dewatering pumps, it’s important to factor in the total cost of ownership that accounts for the likelihood of more frequent replacements or service calls. There are two scenarios when it comes to dewatering:
- Maintaining a constant water level whereby you match inflow to outflow; and
- Drawing down to allow access to greater depths, which requires pumping a greater volume than expected as inflow
The need for the right equipment continues throughout the entire life-cycle of your project. For example, you would require higher pumping rates when you begin dewatering in order to clear out groundwater storage and hit the target drawdowns. However, once you have reached the necessary levels, typically the pumping rate you need will also be lower.
The use of a pump shroud in a dewatering application is highly recommended, as excessive heat will kill your motor. With varying flow demands typically experienced in a dewatering application, the shroud must be sized to ensure an adequate velocity passes the motor to keep it cool not only at your duty flow but at your upper and lower limits.
Optimise flow rate
Once you’ve chosen the right equipment, the next step is to optimise your flow rate. A common error that tends to occur is operators setting the pump for the maximum inflow rate. The problem, of course, is that the pump is now oversized when compared to the average incoming flow, which means unnecessary energy consumption and costs.
A sound rule of thumb is to not pump outside of parameters as follows. Select the pump Best Efficiency Point (BEP), your upper limit being no more than 10% higher, and the 50% of BEP will be your lower limit.
Scenario a, as outlined above, is best handled with multiple pumps running in parallel which will allow you to match the inflow and drop off pumps as the demand decreases. For scenario b, the pump should be selected right of curve initially to allow for a lower required operating head, which normally coincides with a higher flow demand. As the draw down occurs the system head will increase and the pump will naturally move left on the curve. There is a limit to the range you can expect to get out of the pump and regular checks on flow and pressure will ensure you operate in an optimal area. This will allow for peak pumping efficiency within that range which has the dual benefit of keeping energy cost down and lengthening the pump life span by reducing internal radial and axial forces. These will result in accelerated pump wear and premature failure.
This approach has been shown to reduce both energy costs and the associated greenhouse gas emissions.
Review your energy usage
Many operators focus on lowering the initial capital expenditure when it comes to bore pumps and don’t consider the fact that you can actually continue to optimise your usage after installation. Studies have shown that energy and maintenance costs will account for up to 50–95% of total pump ownership costs, with initial costs less than 15% of pump life cycle costs.
In order to reduce your costs, it is best to regularly review the operation of your pumps and look for areas of improvement. What’s more, as future carbon tax levees come into place, the reductions you make in your greenhouse gas emissions and energy costs will benefit your bottom line, all without affecting your dewatering schedule.
Looking for the best borehole pump packages? Get in touch with our pump specialists today or free call us on 1800 439 607.
