If your business uses compressed air to clean, dry, or cool, your air system may not be as efficient as you think – in fact, the worst offenders are less than 10% efficient. For many applications, it is advantageous to convert to a blower based air system which leads to long term cost savings.
Blow-off of water, dust, coolant and other contaminants, drying, cooling, and heating may all be achieved using either compressed air or blower operated systems; there are several factors to consider when choosing the best system for any application utilizing air. Each factor carries varying weight depending on the application specifics and the existing infrastructure.
1. Energy cost
2. System cost
3. Maintenance and operating cost
4. Application particulars
5. Availability of electricity
6. Space and weight
7. Noise considerations
1. ENERGY COST
Blower operated systems, particularly for continuous flow applications, are almost always the more energy efficient choice. Some blower installations can reduce energy costs up to 80% over previous compressed air systems. When used for the right application, blower bases systems often have an ROI of less than one year due to significant energy savings.
In applications where the need for air is sporadic or in short bursts, the amount of energy consumed by a compressed air system decreases. In these applications compressed air may be the energy efficient solution.
For both system types, implementing a proper control system can further minimize the air and power consumption. TIP: If you're looking to change from compressed air to a blower system or vice-versa, ask your supplier to provide an ROI to see how quickly the change will pay for itself.
We’ve written a lot of articles about blowers over the years. Here’s a roundup to help you navigate the content we have available.
Have a question not covered by one of our existing articles? Let us know! You aren’t the only one wondering.
We spend a lot of time analyzing the large components of a hot air system – the heaters and blowers – but we should not ignore the secondary components, such as hose, or it can compromise the whole system. In the past, we’ve seen systems that have the correct heater and blower installed but are failing to produce results because of errors in setting up the hose and connections. There are several things you need to consider when it comes to selecting and setting up your hose connections:
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Recirculating heat systems capture and reuse excess heated air that would otherwise be vented to the atmosphere, improving system efficiency and lowering power consumption. Because the heat is recirculated, the intake air stream through the blower and heater is at a much higher temperature than in a typical process heat system. Non-specialized heaters and blowers are designed with the assumption that the intake air is at or near room temperature, the higher inlet temperatures associated with recirculating systems will damage these tools. Specialized equipment is available that is designed to withstand the high inlet temperatures of recirculating systems. In this article we discuss these specialized pieces of equipment and how they differ from the equipment used in non-recirculating process heat systems.
Hot air systems, at their most basic, combine two components—a stream of air supplied by a blower/compressor and heat generated from a heating element—to produce hot air. Sometimes these two components are supplied by a single tool, other times they are supplied by two separate tools. The goal is to increase the temperature of the stream of air and to use this air for a task. Understanding how air flow and temperature relate to each other is helpful when choosing air and heat sources for your system to ensure your system will be able to do the work required.
Raising the temperature of air requires energy; the amount of energy required depends on the volume of air and the magnitude of the temperature increase. Air heaters are rated by power in watts or kilowatts which specify the energy that the element is capable of applying per unit of time. See our article on The Basics of Heat Calculations for further explanation.
There is an inverse relationship between air flow and temperature. For example, if the air flow over the element increases then one of two things happens: to maintain a constant temperature the element must increase its power output or the temperature of the output air will be lowered.
Or – Why a HOTWIND might not be the tool for you
Here at STANMECH, one of our most common customer requests is for the HOTWIND hot air blower. The HOTWIND is a well-designed combination heater/blower and it works extremely well in the right application. The attraction is obvious: it's everything you need in a compact package, it is capable of reaching the target temperature you require, and it looks more affordable because it’s only one unit rather than two.
However, the HOTWIND is often chosen for the wrong reasons. This type of tool incorporates a specific blower and a specific heater; unless the application lends itself to that exact blower and that exact heater size the tool is simply wrong for the application. This is true of all combination hot air blowers not just the HOTWIND.
The practical application of blower curves
How a blower will function once it is connected to other components is often misunderstood, which can result in the selection of the wrong tool for an application. In previous articles we have discussed the differences between centrifugal and regenerative blowers, how to interpret blower curves, and the differences between flow, velocity, and pressure. This article expands on these topics with a practical case that shows how these concepts interconnect.
When looking at a list of specifications for a blower you will find values for the Maximum Volumetric Flow Rate and Maximum Operating Pressure. While this is good information to have when selecting a blower, in most cases, it is not nearly enough information to predict the blower’s performance once it is part of a system.
Pressure Drop: A Key Piece of (Often) Missing Information
When designing a blower-based system, it is important to understand the concept of pressure drop, how it affects blower performance, and how system design affects it. Pressure drop is the difference in pressure from one point in a system to another. When sizing a blower for a system, the most important pressure drop to consider is from the outlet of the blower to the end of a system (usually where it vents to the atmosphere). This is often referred to as the back pressure on the blower, or the operating pressure of the blower.
What does “drying” mean?
At STANMECH Technologies we get many requests for drying solutions. Often the customer immediately asks for a heat solution for drying. This is understandable, using heat to dry is a common occurrence in our everyday lives from clothes driers to hair driers. In this article we will explore why hot air is not always the best drying solution and talk about using fast moving air as an alternative to heat. We will also give guidelines that help to decide when to use heat and when to only use air.
Firstly let’s clarify what drying can mean. The term is used in many ways that can be open to interpretation. The term “drying” is commonly used to describe the following types of applications:
In some cases the term “drying” is misused and it would be more correct to say curing. Regardless of the terminology the important point is that not all of these applications are good candidates for using heat to accomplish the end goal.
Both regenerative and centrifugal blowers are widely used in industrial processes. Superficially the two types of blowers can seem similar and it can be difficult to find good information on the differences between the two types and blowers and why one would be selected over the other.
First, we’ll discuss what the two types of blowers have in common. Both types move air using an impeller on a rotating shaft. The air comes in the inlet and is focused while traveling with the impeller before exhausted as linear flow at the outlet. This is where the similarities end.
Air knives are used in many industries to remove unwanted materials from processes. This can range from blowing water off of bottles in a bottling facility to removing cooling fluid in a metal rolling plant to removing crumbs from a bakery conveyor system. Although the use of air knives for blow-off is widespread, so are the errors in set up that cause ineffective or inefficient operation.
In this article we will review some of the fundamentals of implementing an effective blow-off system.