Category: Cooling

A Comprehensive Guide to Variable Frequency Drives

Variable frequency drives (VFD) are used in appliances and compressors of all sizes. They can help make electrical motors more efficient. They work by managing the frequency and the voltage so that they use energy in the most efficient manner possible. They are being used more and more as the development of the technologies has made the drives smaller and improved their performance. Here are some things to know about variable frequency drives.

AC Motor
Usually the motor for a variable frequency drive is a three phase induction. This is because such motors are generally the most economical. Less commonly used are wound rotors, permanent magnets, and synchronous motors.

Controller
A VFD has a controller that runs because of three sub-systems. Those sub-systems are the converter, the DC capacitor, and the inverter assembly. The converter stage is where the AC voltage is converted to DC voltage. The DC capacitor assembly and the inverter assembly work in tandem to initiate the three phase voltage. In 1983, the insulated gate bipolar transistor made it so that a VFD cost less and improved its amperage ratings.

Operating
VFDs have an extensive operator interface. It can start and stop the motor, as well as adjust the speed. There are types that allow for reversing the motor and even switching from manual control to automatic. VFDs are operated by either a computer network, digital controls, or the operator interface controls on the unit.

Drive Operations
A VFD will have three options for driver operations. Single quadrant operations are most common, and involve using constant or variable torque. Two-quadrant loads are needed when the torque alters its polarity but the speed is constant. For the highest performance, a four-quadrant load can handle speeds and torques that change direction and force.

Types of Variable Frequency Drives

Controlled Source Inverter
A controlled source inverter (CSI) works by using a SCR converter to convert all the incoming power to DC. CSI have a large internal inductor so that they can work efficiently and properly to handle the incoming power load. The advantages of this type of VFR are that the circuitry is relatively simple, they are very reliable, and they are capable of regeneration. Some of the drawbacks are that it relies on that large conductor, which is expensive, and that it is not compatible with multi-motor applications.

Voltage Source Inverter
Voltage Source Inverters (VSI) are similar to CSI in that the prime function is the covert power to DC by using a SCR converter section. However, VSI drives cannot regulate current, which the CSI drive can do. The VSI can create an adjustable frequency output for motors.

Pulse Width Modulation
The pulse width modulation (PWM) design is the most common drive controller. It can work with the largest variety of motors, and is very reliable. It is the most sold by manufacturers as well, so there are many brands from which to choose. As opposed the the VSI and CSI drives, PWM converts AC voltage to DC voltage. It does this by using an inverter section that also has gate bipolar transistor that are insulated. This creates a near-sine wave output. These drives are a low cost upfront, are compatible with multiple motors, and can operate through a power loss. The only issues are that it cannot regenerate, and can break down because of the switching transistors.

Benefits of Variable Frequency Drives
VFDs come with a host of benefits. For one, they are very energy efficient, in particular with regards to centrifugal load service. Estimates show that well over 60% of all used electrical energy is consumed by power motors. VFDs and other efficient technologies help to reduce that energy footprint.

Performance Control
VFDs allow you to regulate the amount of power a motor delivers. With fixed speed drive, a motor might be delivering more power than is needed. To have better process control, VFDs will regulate that power and only use as much energy as is required.

Now you know about the different types and benefits of using VFDs. Make sure to choose the right one for the job you have to do.

If you want your HVAC system to run more efficiently, the experts at Corporate Mechanical can help. Reach out online or call 763-533-3070.

Tips to Save Air Conditioning Energy This Summer

There may be nothing better on a summer’s day than to come in from the hot weather, thirsty and sweaty, to a nice cool building. Air conditioning has become a lifeline for so many in the summer who cannot stand the heat. Unfortunately, your air conditioner uses a lot of energy, and can be quite costly. Here are some tips to keep your energy consumption low this summer.

Seal and Insulate

Make sure your building is well insulated, and seal any spots where air from the outside can get in. If hot air is coming in, then your HVAC system will have to work harder to cool down the building, which will cost you money. Your entire building should be well insulated as well, to keep the heat out and the cool in.

Use a Fan and Shades

Yes, a traditional fan can save energy. A standing fan or a ceiling fan can help circulate the cool air to better cover every spot in the building. On days that are not too hot, you can turn off your AC and use fans to be cooled by their breeze. Shading your windows will also help prevent your building from getting heated up by sunlight like your car does on a hot day.

Use a Programmable Thermostat

A programmable thermostat can be set to only run the air conditioning at certain times of day when it is most needed, or to maintain a certain temperature. You can set it to a slightly higher temperature than what you originally want, as well. Instead of setting it low to get an immediate blast of cold air, set it a bit higher. You’ll cool more slowly, but you will not work your AC system as hard.

Use A Swamp Cooler

A swamp cooler evaporates water in the air, so that the area cools. It uses much less energy than a compressed air AC system. The windows should be left open for this method.

Maintain Your Filters

Your filters can get clogged with all sorts of debris, so make sure you change them regularly, especially if you have pets. The less airflow there is because of a clogged filter, the harder your AC unit will work.

Do not let your energy costs get out of control this summer. Save energy with these helpful tips.

Tips for Office and Warehouse Air Conditioning

We all know it is tough in the summer to live in a home with no air conditioning. Sleeping can be difficult and uncomfortable, cooking makes it even hotter, and you probably do not want to snuggle with your kids or a significant other. What about work, though? It is important for workplaces to be kept comfortable as well, so keep staff and customers happy. Here is some advice regarding air conditioning in commercial settings.

Capacity

With larger spaces holding more people, the unit at your office or warehouse should have more capacity than a residential unit. People, plus machinery, combine to heat up the property, so you need to have the power to cool everything down.

Evaporative System

In a factory or any large commercial space, there are extra challenges when it comes to cooling them down. An evaporative air conditioner might be a good option. They use less energy than traditional air conditioners, which means they’re cheaper to run. They are very good at cooling large factory settings with lots of hot machinery, as well.

Machinery

Speaking of machinery, you would be surprised at how much they can add heat to a building. And it is not just large factory machines, either. Computers, printers, and photocopiers will also give off heat and make any office hotter. When you’re getting a quote for air conditioning, make sure to notify the contractor how much machinery you have, so they can get a good gauge on how much capacity you’ll need.

Keep Everyone Happy

There is no doubt that productivity can suffer if a workplace is not property air conditioned. Instead of working, staff will be fanning themselves, talking to each other about the heat, and generally being distracted by their discomfort. Also, if you have an office or a shop where clients come in to see you, then they may not come back if they were not comfortable. The important thing is setting your thermostat so there is a good balance between too cold and still hot. You’ll have staff and clients that have different comfort levels, so it is important to try to please everyone as best you can.

It is important for any workplace to provide a comfortable space for both workers and clients. Use these tips to keep productivity and comfort at high levels.

Xergy Currently Developing Greener HVAC Systems

Bamdad Bahar is the founder of Xergy. Xergy is a Seaford startup that is working to find a way to make greener HVAC systems for homes and businesses. Their goal is to find a way to convert the membrane technology used in fuel cells for climate control purposes. As a result, modern HVAC systems will be more environmentally friendly. Says Bahar of the project, “There are literally hundreds of applications for this membrane technology in everything from electronics to industrial to medical. But right now refrigeration and air conditioning is our main focus.” But what does this technology entail? How is it different from traditional HVAC technology? And how is Xergy currently developing greener HVAC systems to use on a larger, nationwide scale? Continue reading “Xergy Currently Developing Greener HVAC Systems”

What Are The Advantages Of Walk In Coolers?

The advantages of walk in coolers mainly revolve around convenience, flexibility and operating cost. They are also available in different styles and designs, unlike regular units. They are regarded as one of the best options for keeping food fresh for a longer period of time. This is attributed to the fact that they are so advanced. Most models are energy efficient and are a perfect choice for those looking to save money on their electricity bill. Walk in coolers are very durable when compared to other types of cooling systems.
Continue reading “What Are The Advantages Of Walk In Coolers?”