Variable Speed Compressors for Improved Energy Efficiency
Energy efficiency is one of the most important factors all businesses are concerned with. The more efficient your air system, the lower your energy consumption and the cheaper your energy bill!
A vast amount of the energy that is lost in a factory or plant is due to wasted energy in an air compressor installation. This can have a huge effect on energy costs, raising your bills and making your cost of ownership high. Various technologies have been developed to ensure that compressed air systems are performing as efficiently as possible, one such technology is variable speed drives (VSD).
Traditional air compressors are fixed speed, meaning they run at a constant and consistent speed. This produces a fixed amount of compressed air per minute. There are many benefits to fixed speed compressor technology if your compressed air demand is constant and unchanging. However, this isn’t always the case. As fixed speed compressors are always operating at full-throttle, if all of the output is not required then energy is being wasted.
Furthermore, fixed speed compressors run unloaded as the stress of an engine start-up would put pressure on the motor. This can be a waste of energy as the machine is running without producing any compressed air. Variable speed compressors avoid this issue by matching the output with the demand created. By simply producing the exact amount of air being used by the downstream equipment, variable speed compressors help to improve plant efficiency.
Watch this video to see how a fixed speed compressor can be sequenced with a variable speed machine to precisely match output with network demand to save energy.
Many air compressor installations will benefit from the efficiency variable speed drive technology provides. Whether you are in the food and beverage industry, automotive, medical industry or even manufacturing, there will be times when your demand for compressed air will vary.
A combination of both variable and fixed speed compressors is thought to be the most cost-effective and advantageous set-up, resulting in the most energy saved and demands met.
Thermocompressor Installation & Troubleshooting
A thermocompressor is a steam control device that uses high-pressure steam (motive steam) to induce flow from a lower pressure steam source (suction steam) and discharge the mixture at an intermediate pressure. The high pressure is used to create a high velocity jet that mixes with and accelerates the suction steam. The velocity of the mixture is exchanged for increased pressure in the diffuser. A Kadant Johnson thermocompressor is shown above.
Thermocompressors can be installed in any orientation, but directing the discharge horizontally or downward is preferred. A thermocompressor should be independently supported. Using the unit to support piping can impose excessive loads and cause bending and misalignment.
Suction and Discharge Piping
Suction piping must be independently supported. It should be full size to match the suction connection on the thermocompressor. Avoid filters, valves and other fittings that cause pressure loss in the suction line that were not considered in the original design specification. Use low-pressure drop non-return valves and full bore ball or gate type isolation valves in all locations to minimize pressure losses. Avoid low points or loops that might accumulate condensate. A steam pressure gauge with an isolation valve should be located as close to the low-pressure inlet as possible.
Discharge piping should be the same diameter as the discharge connection on the thermocompressor. Discharge piping must be independently supported. Care should be taken to avoid placing restrictions or undue obstructions that will increase the discharge pressure above the design point. A minimum length of 10 pipe diameters is recommended before an elbow to Tee. A steam pressure gauge with an isolation valve should be located as close to the discharge connection as possible.
The line size should be determined based on the maximum design flow for the thermocompressor. Dry steam is a basic requirement for good performance and wet steam is extremely detrimental to both the performance and the parts of a thermocompressor. Motive pipe runs longer than 10 feet and should have a drip leg and trap to remove condensate from the piping before the motive steam enters the thermocompressor. High-flow losses in the supply lines should be avoided. As the motive pressure falls, the amount of steam required increases. A steam pressure gauge with an isolation valve should be located as close to the motive connection as possible.
A thermocompressor in the fully open or closed position during run conditions is usually a problem. Accuracy of the instrumentation and controls should be verified.
Substandard performance can usually be traced to either external or internal causes. Substandard performance can also be classified as either sudden or gradual. A gradual deterioration in performance, usually a loss of recompression, invariably suggests either erosion or corrosion, whereas a sudden loss of compression will usually suggest an external cause.
Since the external causes of trouble are usually easier to check, they should be investigated first.
When a fault is investigated, it is prudent to treat as suspect all the gauges fitted, especially Bourdon Tube type dial gauges. These gauges should, whenever it is possible, be recalibrated.
4 Types of Refrigeration Systems
Evaporative cooling units are also referred to as swamp coolers. They work by blowing warm outdoor air over pads that are soaked in water. The water’s job is to absorb the heat from the air. The water then evaporates and cooler air enters your home while warm air stays out.
An evaporative cooling unit is capable of reducing the temperature in a home by about 15-40 degrees. If you’re in the southwestern U.S. where the climate is dry, evaporative coolers are for you. An evaporative cooling unit is easier to install and doesn’t cost half as much as a central air conditioner.
Mechanical-Compression Refrigeration Systems
Mechanical compression is used in commercial and industrial refrigeration, as well as air conditioning. Most HVAC companies install this type of cooling system.
By mechanically compressing refrigerant into a cold liquid with low pressure and expanding it into hot gas with high pressure, this type of system transfers heat. Refrigerants work when pressure is applied or removed. When they absorb heat, they boil and turn into gas, then turn back into liquid form when they release that heat. The refrigerant in a mechanical-compression system boils at 40 degrees, sucking the heat out of warm indoor air.
The process in absorption refrigeration is similar to how heat is transferred in mechanical compression. However, instead of using a mechanical compressor, absorption systems use refrigerants that attract and absorb other substances. In some systems, for example, ammonia acts as the refrigerant and water acts as the absorbent. Instead of relying on electric power, heat can come from water, natural gas, steam or other fuel sources.
These systems don’t need water or any type of refrigerant. They rely on a thermocouple and electric current. One end of the thermocouple is hot and the other end is cool when current is directed to it. The cold side of the thermocouple is placed in the area that needs cooled so it can attract heat and remove it from the air. Thermoelectric refrigeration isn’t usually used for large cooling loads, but it’s perfect for hard-to-access small cooling loads. A good example would be electronic systems.
What is the difference between a fixed speed and an inverter air con?
Inverter or non-inverter? This is the question we get quite a lot from homeowners and business owners that want to purchase a new air con. As you already know, different factors such as building size, floor plan, price and energy usage need to be considered in the search for the best results. These days, though, you may find that most air conditioners are inverter models.
Before you choose an air conditioner, you may wonder: ‘Should I choose a fixed speed or an inverter air con?’ In order to decide which one is better, you must first understand the difference between the two types.
Let’s look at the mechanism behind both systems, so that you can make the best choice possible.
A fixed speed, also known as non-inverter or standard air conditioner, features a single speed motor operation: on and off. Basically, once it reaches the desired temperature, it turns off, then back on when the temperature rises to a set level. In other words, this standard compressor always runs at full speed or stops completely depending on the temperature requirements.
This model may be a good option if you are on a budget and you want to save on upfront costs. Since there aren’t many components to deal with, repair charges are usually cheaper as well.
On the other hand, due to their ‘on and off’ cycle, fixed speed air cons use a significant amount of energy. That means they are much less efficient compared to modern technologies. They also fail to keep a constant temperature in your home or office, thanks to the system limitations.
So if flexibility, performance and energy efficiency are on top of your priorities list, then you may want to take a look at an inverter air conditioner system.
Inverter technology is typically considered to be a better choice if you’re looking for the optimal domestic or commercial air con performance.
Technically, the inverter air con controls and varies the speed of the compressor motor, similar to a car. The compressor from the outdoor unit doesn’t have to switch on and off continuously. In exchange, it speeds up or down when necessary in order to keep a constant, comfortable temperature at all times.
Plus, due to its efficient operation, there is less stress on the compressor, as well as on the other parts of the system. That means you’ll save money not only on electricity but also on maintenance. What’s more, an inverter air con features higher energy ratings than a non-inverter one, which makes it friendly with the environment, too.