Tag: <span>evaporator</span>

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Working with Air Conditioning Contractors

When dealing with a breakdown of you central heating and air equipment, you don’t want to struggle finding honest, reliable help when you’re pressed to find relief from the sweltering heat or bitter cold. Right off the bat you should know you’re getting help from a qualified and skilled professional able to handle any repair or situation that is put before them. You might wonder who you can trust, and what you can expect them to do for you, or if its worth it to call a local service provider? These questions can be easily answered and give you the desired results for any service need you have.

When Should You Call a Local Service Provider?

Some homeowners may attempt to fix their air conditioning system on their own without having a good understanding of how to deal with bigger issues. If you are attempting to work on your own furnace, air conditioning system or heat pump, look for these noticeable signs that may indicate a bigger problem that would be best handled by a professional.

Furnace

• If your furnace is older, 15 years or more, it may need to be replaced. normally the first 4 digits of the serial number will give you the year and week of manufacturing.
• If it is making strange, abnormal noises.
• If cold air is coming out.
• If a carbon monoxide detector alarm is going off in your house. It is recommended that homeowners with natural gas appliances have several of these in bedrooms and other locations around the house.

Air Conditioning System

• If your air conditioning system is 15 years or older, it may be more cost effective to replaced it versus repair
• If your system uses R22. The EPA has mandated that all manufacturing of R22 be stopped, driving up the cost and price per pound in your area.
• Continued breakdowns year after year may indicate a bigger problem that a contractor is better equipped to handle.

Heat Pump

• If either unit, indoor, or outdoor is not performing well
• If temperatures are staying even throughout the house.

Finding a Qualified Contractor

In this internet driven age, most homeowners will pull out their smart phone and research local contractors in their area. Many search engines like Google will provide all the information in a concise format, providing reviews, website info, and contact information. Yelp is also a great resource for homeowners to peruse reviews and read feedback provided by the owner, or management of the company. Even companies with several bad reviews help homeowners see how the company handles conflict resolution, and helps you know what to expect. The number of reviews is not always the best representation of that companies customer service. Look at the quality of each review that describes the experience of the consumer.

A quick search at https://www.tdlr.texas.gov will also provide you with information about a potential contractor. This is the governing and licensing agency for all contractors in Texas. All advertising material and websites should list the contractor’s license number. The Texas Department of Licensing and Regulation will provide information about the licensee and their current status. The following guidelines below will also help you find a qualified, trustworthy contractor.

Knowing Who to Trust

Most Homeowners want to find someone trustworthy, who is reliable and who they’re able to call in the future should the need arise. Here are a few tips to ensure you get quality workmanship from a contractor. Make sure they are qualified! A contractor that is licensed and insured will have no problems producing proof of such to a prospective customer. Don’t be afraid to ask if they are licensed and insured. Insurance is required by the state to protect both the contractor and the consumer. Knowing this information prior works out for both parties involved. If you can’t find this information readily available on their website (usually in the footer or bottom of the homepage near their contact info) don’t hesitate to ask.

If a air conditioning contractor has additional certifications, that information will usually be present on their website. NATE technicians are the industry’s gold standard in technical proficiency. NATE stands for North American Technician Excellence. Testing and certification for NATE is rigorous and comprehensive, ensuring you’re dealing with someone who is able to proficient in troubleshooting and air conditioning system knowledge.

The price of the contractor is important!

One of the greatest determinants for most homeowners when it comes to repairs, or replacement options for central heating and air conditioning is price. Neither the highest price or the lowest is an indication of quality, or value. Most contractors work very hard to minimize the cost or find a cost effective solutions that works for their customers needs. Smaller companies or family owned and operated outfits will typically provide high quality work, and be more competitive than larger companies that rely on a certain sales volume to cover the cost of their high overhead.

Equally as important as price though is the warranty. You want the assurance of knowing your air conditioning repair is backed by the company that performed the work. This also shows that the contractor has faith in their own work as well. A good contractor will also have a contingency built into most repair estimates, or may choose to offer you good, better, best options for repairs or replacement. Not every customer wants the same thing, or level of service on every call. A good contractor also will not typically discuss pricing over the phone until they have had a chance to survey the situation, or diagnose the issue

Size is Important

If system replacement is what you are looking for a contractor should provide a size assessment of your home. Ensuring your home’s air conditioning system is sized correctly is important for your comfort when it comes to single stage systems and base line models of air conditioning systems. Higher SEER rated equipment or multistage or variable speed equipment will provide superior comfort than most of the base line models, and also result in savings on your utility bill. A good contractor will provide several options and be able to explain the difference and benefits of each system. Ask about what methods the contractor used to determine the size requirement of the air conditioning system for your home. Manual J software, blower door tests, HERs raters(for new construction, required in certain areas) and other technologies are used by quality contractors to determine this.

What Does a Contractor Do?

After you have found a contractor you can work with you may wonder what to expect next while they are working at your house. A contractor will typically carry out these tasks during installation, repairs or maintenance.

• Equipment should always be installed according to the manufacturer’s specifications, using the industry best practices.
• Connecting systems to different fuel and water lines.
• Connecting air conditioning ducts and sealing to prevent air loss.
• Installing electrical controls and wiring according to code
• Performing tests on the equipment, and controls during and after startup
• Inspect and asses any type of HVAC system.
• Test individual parts of the system to isolate and diagnose what needs fixing.
• Replace or repair whatever is broken or defective.
• Performing routine maintenance to ensure the HVAC system is running efficiently throughout the year.
• Replacement of filters and clearing of drain lines to maintain the efficiency of your system.
• Cleaning of condenser coils yearly or quarterly
• Cleaning of evaporator coils periodically or as needed.
• Tightening electrical connections or lugs, or periodically replacing components that are worn and may cause greater issues down the road for components connected to the electrical supply.

Quality Contractors will typically employ sophisticated tools that are essential to your systems function, performance, and reliability. They will also typically discuss best industry practices they employ to ensure the reliability of your system. Vacuum pumps, recovery machines, acetylene torches and combustion analyzers are tools typically employed by good contractors.

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Source by Jon Riddle

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Building your custom wine cellar should be accomplished in as smooth a way as possible, from concept to design to the complete installation, may it be in residential or business locations. The design process (the phase where you get involved the most) should be an experience worth having rather than a troublesome and unpleasant one for you. Know more about the effective key points and guidelines to follow so you can get started with your design.

Define Your Elements

Custom wine cellars should be as unique as every individual is, so you can take the liberty of designing what suits you. For a wine storage solution that efficiently functions at its best, it is essential that you gather all your long-kept dreams and ideas and begin the process of realizing them. Here are some of the essential elements you need to consider in obtaining a custom wine cellar design:

• Wine cellar (size, style, space)
• The style and size of your wine room will depend on the number of bottles you need to store and also the location. It is very important to determine whether you want to focus on functional benefits, or beauty of presentation, or both. Decide on a space that is not directly exposed to sunlight. You definitely do not want to damage your wines due to temperature changes caused by improper wine storage. This is one of the reasons why wine bottles are colored and ideally stored in dark places.
• Wine racks (size, style, wood specie and wood finish)
• Different wine cellar manufacturers offer different wine racking solutions. Wine racks come in many different sizes – six feet, seven feet, and eight feet heights. These are usually modular in nature to allow more customization options such as adding a top shelf, bin extender, cubicle extender, curved corner wine rack, display wine rack, and other interesting options. Pick a style that suits your taste, greatly enhances the appearance of your wine collection, and compliments the interior of your home, commercial venues, or even luxury yachts.
• The type of wood species also defines the quality of your wine rack so carefully pick wood types that promise durability, usability, and exotic beauty. Wood stains also play a vital role in boosting the glamour of your wine display so know the staining products that match the properties of your chosen wood specie.
• Wine cellar door (design, size, and other specifications)
• Captivating wine cellar doors give elegance to a wine room and sizes come in custom and standard dimensions. The doors can be customized in terms of width, jamb size, door swing, casement moldings, hinges, automatic door bottom, threshold, stain, and other features you want to include. You can even get them hand carved or with the glass etched with your design, the possibilities are endless. Review these options with your wine cellar specialist and always perform a quality check to ascertain longevity and maximum performance.
• Wine cellar flooring (use of wood, old oak barrels, and other flooring materials)
• Highly recommended is the mainstay flooring material wood as it can tolerate humidity levels typical of a wine storage room. One good tip, don’t use carpets since they tend to develop mustiness and molds due to the humidity. Surprisingly, some wine cellar experts recommend recycling of old oak barrels to use as wood flooring material as they represent originality and natural beauty as well as making sure they are kept out of landfills making your cellar truly ‘green’.
• Wine cellar cooling system (types and factors to consider)
• First of all, you need to know that home air conditioning units are totally different from the wine cooling equipment which are specially engineered to control the temperature and humidity levels inside the cellar. It is important that a controlled environment condition is maintained to promote proper wine cooling and wine aging, and prevent undesirable changes to the taste, smell, and general characteristic of your wines.
• One of the popular types is the wall-mounted cooling unit which is usually designed to vent to an adjacent air-conditioned space or other units can have both interior and exterior vents. Another type is the self-contained cooling unit which can be placed free-standing inside the wine storage room or in an adjacent room and vented to the wine room through insulated ducts.
• Split systems, on the other hand, can handle more extreme temperature levels and are less noisy, and its evaporator is installed inside the wine cellar while the condenser is placed outside or on an adjacent room.
• Some of the important aspects to consider when choosing a wine cooling unit are the size of the wine cellar, noise levels of the unit, installation and the need for a licensed technician, price, and length of the warranty.
• Other factors to be considered
• You may also specify the lighting effects and ambiance you want to achieve. Do you want lights that dim, a fancy chandelier or is your wine cellar contemporary in style? Are your wine racks going to have a display rack and do you want to highlight the wines being shown there? There are many options to consider and if you have a good custom wine cellar designer they should be able to guide you in picking the right fixtures to complement your wine cellar.
• And Finally:
• Before you call a custom wine cellar specialist, make sure you have a good idea of the budget you have to work with and don’t forget to get a clear idea of the timelines involved so there are no surprises.

Let your Unique Ideas be Heard

After making a list of your ideas, wants and needs get in touch with a design consultant and discuss every single detail involved and be very careful not to miss out on any aspect as this is supposed to be your dream! Choose a wine cellar builder that has well-trained, knowledgeable, and customer-oriented consultants who can guide you as you work together in forming and visualizing your ideas and concepts.

Ask for a 3D Design

An initial sketch made by the consultant can be converted to a 3D design, done by a CAD (computer aided design) team. The 3D presentation enhances your understanding of the concept and lets you know what to expect, so a wine cellar builder that offers this package is worth the choice.

Give your Approval

A cellar designer should contact you to find out if you’ve gone through the design presentation and to answer any questions you may have. If you are happy with the design, you can readily approve the proposal and let them begin the process of realizing your dream.

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Source by Juliette Johnson

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A broken air conditioner can make driving unbearable during the sultry summer months. A minor inconvenience the rest of the year, an inoperable A/C is most certainly an emergency situation when the mercury rises. Here are the most likely reasons your unit is on the fritz.

Refrigerant Leaks

Refrigerant is the substance that is responsible for cooling the air that comes out of your A/C vents. When properly pressurized in a closed-loop system, refrigerant evaporates into a gas that is later used to cool an interior space. But when there is a leak in this closed system, refrigerant levels may fall, inhibiting operation. In other words, the fan will only blow hot. A fairly common car air conditioning repair issue in older vehicles, the challenge is actually locating the leak. The reason? Unlike oil or antifreeze leaks, drivers will not find puddles of fluid under their vehicles when refrigerant escapes. More often than not, an oily residue is the only sign that something is wrong. We should also note that a leak can occur almost anywhere in the system, including in the compressor, condenser, or the evaporator. As such, the entire unit must often be examined to properly diagnose and correct the issue.

Electrical Problems

If your A/C unit isn’t working at all, the problem could be electrical. Fuses, relays, pressure switches, and other electrical components can fail at any time because of age or defect. When this happens, the system is designed to shut itself down for safety reasons. The inevitable result is an air conditioner that will not respond when switched on-not even the lights will work. Only an experienced mechanic has the knowledge and tools to isolate the problem with diagnostic testing.

Bad compressor

Another common car air conditioning repair problem in older vehicles is a worn-out compressor. The heart of the unit, the compressor is responsible for circulating refrigerant throughout the entire system. When it breaks down, the vents will only blow warm. Although age is the most common culprit for compressor failures, the vital component can also fail because of contamination or other faulty parts. A visual inspection of the part is often all a mechanic needs to diagnose the problem. If it cannot be repaired, the compressor must be replaced.

Clogged Air Filters

Attached to the outside intake of your car’s ventilation system, the cabin air filter removes dirt, dust, and pollution from the outside environment before it is pumped inside. When this filter gets clogged with all the debris it collects, airflow may be adversely affected. If your A/C vents are sputtering or barely blowing, there’s a good chance that an obstruction in the filter is to blame. Simply removing and cleaning this component is often enough to get things blowing again. Because it is an inexpensive, automotive part, it may be a good idea to simply replace it with a new one.

These common car air conditioning repair jobs can be completed by any qualified mechanic.

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Source by Alfred Ardis

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The commercial refrigeration units may cause the owners a hefty bill running into thousands of dollars if energy-saving tips are not applied. These units are heat and cold processes and mostly used for the food and processing industry.

Many grocery stores also have a deep freezing system to protect varied types of food products. According to an estimate by the Energy Department, the commercial refrigeration consumes around 17,000 KW hours of electricity. The larger units may use 38,000 KW hours of electricity.

Here are four vital energy-saving methods that can improve the process efficiency of such refrigerators:

1.Cleaning the System

The condenser and evaporator coils should be thoroughly dirt-free, which will maximize its lifespan. The dirty coils in this system will cause it to work hard. As a result, it will pull the amps. It is advisable to clean the coils and keeps them dirt-free to save on the energy. This will help in saving extra bucks on the system.

2.Choose Good Refrigeration Equipment

It is advisable to purchase the energy-saving refrigeration unit in order to save money for the electricity bill too. One can go for the following buying choices:

• Choose energy-saving models to save on the life of a machine.
• The installed controller with advanced energy-saving methods will help in increasing the performance of the equipment.
• The insulation system with 75 mm thickness and higher quality increases the efficiency.
• The cabinets with self-closing doors and qualitative gaskets will provide a tight seal.

3.Follows Energy Department Standards

The refrigerators purchased by the grocery stores or food industries must follow the latest standards of the Energy Department. These new standards will increase the working efficiency by 30%. They will cut down on the unnecessary energy usage thereby help to save the bills.

• Use the anti-sweat heaters that cause a condensation condition on the display door.
• Installation of the motion detectors to control the lighting system
• A regular check should carry on the automatic door closer operations.

4.Refrigerator Maintenance

The preventive measures for the maintenance of such refrigerators will meet the energy-efficiency needs. The owners can take services from a renowned company that provides guaranteed and economical parts. This will further reduce the running cost of equipment to nearly 20%. One can look forward to the following points for maintaining their refrigeration equipment.

• Follow recommendations provided by the manufacturers.
• Stick to the regular maintenance program to reduce the risk of equipment’s breakdown.
• Keep a check on the gaskets and self-closing doors. Get proper cleaning done by the reputed service providers.

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Source by Frank Shan

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Fridges and freezers come with a number of varying perks to make your life that much more simple. Depending on which perks are interesting to you will very often determine the price bracket of the refrigeration unit that you require. This work aims to consider a variety of the more common among these in the attempt to make your cold storage shopping experience a little more informed.

Automatic defrost/Frost Free

All larder fridges have an automatic defrost function and the term is specific to refrigerators. The function means that, throughout the duration of the refrigerator’s activity, a mechanism periodically heats the cooling element (or evaporator coil), by heating a separate element, in order to free it of icy build up. The timing is controlled electronically and a failsafe temperature switch is used to terminate the heating, should the temperature of the cooling element reach 5°C or 40°F. If you choose a fridge with an ice box, it will need to be defrosted periodically to remove the icy build-up. If the function is used by a freezer unit it is usually called Frost Free.

Antibacterial coating

Some fridges have an antibacterial lining which covers the fridge walls and door which helps prevent the growth of bacteria. This will obviously improve the hygiene inside your fridge. Some refrigerators use silver nanoparticles to resist any airborne bacteria. These also suppress the respiration of bacteria and adversely affects their metabolism resulting in inhibited growth. Similar particles are used in some air purification systems.

Quick cooling/Quick freeze function

This function is now common place among newer refrigerators and freezers. It is sometimes known by a trademark such as SuperCool/SuperFreeze or similar. This rapidly reduces the temperature when new items are added. It quickly cools the new contents to 2°C in a fridge or -18°C in a freezer and automatically deactivates when this temperature is reached. The obvious benefit of this is, since food reaches the ideal storage temperature more quickly, that your goods retain optimum freshness. It also prevents other goods from thawing or heating up when you introduce a large amount of warmer contents.

Active Cooling

This function is where refrigeration is assisted by fans which continuously move air around the compartment. This allows the whole unit to maintain an even temperature, instead of having warmer air pockets, so that your food is in a consistently good environment.

Humidity Control

This usually features in salad drawers of top end models. The humidity control allows the salad to be stored in the optimum moist and cold conditions to retain the best freshness and crunch; considerably delaying that soggy lettuce!

Air Purification System

Some fridges display cutting edge technology for maintaining freshness. Their air purification system allows the stale air inside the cavity to be refreshed and cleaned of bacteria. Such systems also keep food odours to a minimum. Be prepared to pay a premium if you wish to own a unit with such a system, however.

Conclusion

Some fridges come with none of the above features and, as you would expect, are cheaper than those that come with any. Many units combine a number of the above features and the cost usually goes upwards depending upon how many. These devices are offered to make your life more manageable saving you time, preserving your food or, simply, by preventing your fridge from smelling! The ones you require, if any, will be a choice for you and, perhaps, your budget.

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Source by Bruce Smyth

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When the temperature gets hot out, your RV refrigerator can struggle to keep it’s temperature cool enough to avoid food spoilage and to keep your beer at the perfect drinking chilliness. There are several factors that contribute to refrigerator efficiency, such as the sun beating down on the refrigerator side of your RV, or a dirty gas burner creating a poor heating flame. Even the levelness of your RV can cause inefficiency over time. One of the simplest and most effective mods that can be made is to improve the ventilation at the back of the refrigerator by using a fan to direct air up and out of the refrigerator vent column.

An RV refrigerator is not like a residential unit. It uses a heat absorption system rather than an electric compressor, condenser, and evaporator, as a residential refrigerator does. Heat absorption requires removing the heat from the absorption unit via chemicals and air circulation. This is accomplished by convection or draft. A narrow space behind the refrigerator allows cooler air to be drawn in to the space at the bottom of the unit. The air rises and passes over the heat absorption unit fins, and out of the vent on the roof above the unit.

Some refrigerator installations actually prevent this convection action to work. In a typical RV installation, a dead air space can exist directly above the refrigerator. This space can trap warm air and drastically reduce the draft effect. This reduction in draft is why you should do the refrigerator cooling fan mod. While not a cure all for a poor refrigerator installation, a fan can dramatically improve refrigerator cooling performance.

There are several fan types that can be used for this mod. It is recommended that you use one of the permanent-mount types as the battery-powered kind can require frequent replacement of the batteries, especially if you forget to turn the fan off when not using it. Some use computer fans that are 3 to 4″ in diameter. These require little power and move a surprising amount of air.

A thermostatically-controlled fan however, is the best way to install a refrigerator ventilation fan. These are permanently mounted and have a thermostat that provides power to the fan when the ambient air temperature reaches some set point. Different temperature set points are available with the most common switching at 80°F. A switch can also be wired in to the fan’s power supply so that you have control over when the fan is on.

There is some debate as to where the most effective place to install the vent fan. Camco, for example, has a solar powered fan and refrigerator roof vent combination. This puts the fan at the top of the vent stack, pulling air through the lower vent and up through the roof vent. Still others mount the fan at the bottom of the vent stack, right at the lower vent. This position pushes air up through the stack. Both have been found to work equally as well so the choice is your on which way to go. Either way, using a vent fan will ensure a cold beer on a hot day.

Tip: Try to park your RV where the refrigerator side of the RV will be in the shade as much as possible. This will help reduce temperatures inside the refrigerator vent column dramatically. If shade is unavailable and your refrigerator is on the curb side, use the awning to provide shade.

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Source by Mark Corgan

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Usually, dehumidifiers are free from trouble but you need to have them maintained. This involves emptying the tank and cleaning them periodically. This is to ensure that bacteria and any mildew are handled. The coils should be vacuumed to remove the dirt and the power cord and the plug need to be removed if at all they are worn.

Why you need a dehumidifier

When summer comes, there is a lot of humidity and it saps energy from us taking out sleep and eventually causing safety and health issues especially for the elderly in the society. Basements smell musty and damp because of humidity and if the air conditioning is not adequate, you should purchase a dehumidifier to help you dry out the home.

Buying a dehumidifier also helps in the fall and on spring. This is when there is rain and when the temperatures outside do not require any kind of air conditioning. The dehumidifier has humidistat, a fan, a compressor and an evaporator coil. This is what helps the dehumidifier to remove air moisture. This allows you to have a level of moisture that is acceptable in summer.

If the temperatures outside drop and then you place the dehumidifier in your basement, it will lead to freezing up of the coil if it is turned on. In such a case, you only need to turn it off and then try again when the need arises.

There is the portable dehumidifier that is appropriate when there is high humidity. This has to be emptied once every day. If the tank is full, the humidifier automatically switches off and only works if emptied.

Fixing the dehumidifier

It is not hard to tell when you should fix the dehumidifier. When the weather is muggy and hot and there is not too much water within the tank, you need to take care of the machine. You should:

• Clean and then vacuum the coils. When coils are dirty, they will freeze. Whenever they have dust accumulated on them, they need to be cleaned immediately.
• Tighten screws on the shaft of the fan. This is because it is possible that it slipped leading to the failure of the dehumidifier.
• Replace the motor of the fan. This is when you notice that it has very low revolutions in a minute. This is not something that you can do. You will have to find a service technician for this. The compressor may have failed or the dehumidifier may have failed to recharge.

There are also times when you see bent blades. When this is the case, you will need to replace them before the damage gets to your motor. You may have to get brand new ones. Find the name of the manufacturer, and model number available in the manual. This is the best place where blades can be replaced.

The other thing you should always remember is the fact that a dehumidifier can fail due to a faulty humidistat. In such a case, it should be replaced.

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Source by Lyndon Ogden

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Dealing with a broken refrigerator is very stressful. I’ve dealt with a few refrigerator problems in the past. Furthermore, broken and inefficient fridges that are not often maintained usually consume more energy.

Tuning up your fridge periodically is imperative. It is one way of adding more years to this home appliance. Use the following tips to fine-tune your refrigerator:

1. Clean the condenser.

If you have a car, the condenser pretty much resembles the functions of a car radiator. However, the functions of a fridge’s condenser are slightly more complex.

You need to minimize the accumulation of dirt in the condenser. Not cleaning it regularly can actually prevent the refrigerator from cooling. It also prompts the machine to use more energy in lowering down the temperature of the fridge.

Use a special brush found in appliance stores to clean this part of the machine. There are generally two types of condensers in most modern refrigerators. The first one is the static kind. This is directly located at the back of the fridge. The second one is the condenser coil with a fan motor. You can find this inside the card-board part of the machine. It hides the bottom floor area of the refrigerator.

2. Check the door gasket.

The gasket seals the door and prevents cold air inside the machine from escaping. If this is not sealing properly, the machine will run all the time. It will work harder in lowering the temperature inside. It also leads to the pre-mature frosting of the evaporator.

One way to test the gasket is to insert a piece of paper in between the gasket and the fridge. Try removing the paper. If you can easily pull it out, you probably need to replace the gasket.

3. Check the drain and remove collected water.

The defrost heater of the machine tends to melt ice. The excess water drains into the pan that is usually located at the bottom part of the fridge. If you don’t regularly remove collected water, it might spill and cause leaking. It might also make your refrigerator stink.

Use a hair dryer to melt the frost that has collected in the evaporator. It should pass directly to the drain pan. Remove the pan and clean it out. You should unplug your fridge before doing this. You might also want to remove the contents of the machine as water might drain inside the machine.

These are the simple tips that you would want to follow when fine-tuning your refrigerator.

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Source by Alan Cassidy

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From time to time it is reported that on screw chillers using eductors for oil return, when operating at low load conditions, it appears that the eductor does not operate efficiently enough to return a sufficient amount of oil to the oil separator or sump to maintain its oil level, which then causes the chiller to shut down on low oil, a consequence of oil retained in the refrigerant charge in the evaporator.

For such a chiller which uses an eductor for oil return, the cause of the failure may not be low load, but rather low lift. In a comfort cooling environment, chiller load is responsive to outdoor temperature. That is, when it is hot outside, heat flows rapidly into the building and chiller load is high. Simultaneously, the chiller must reject its heat to a high ambient temperature. Hence the chiller operating at a high load condition is also operating at a high lift condition. Lift is defined as the difference between the suction and discharge saturation temperatures (or pressures).

When the outdoor temperature is cool, little heat needs to be removed from the conditioned space and so chiller load is low. The low load is accompanied by a low lift condition since the ambient temperature is down from its high value. The low lift is the cause of the loss of effectiveness of the eductor. The eductor is driven by the pressure difference between the condenser and the evaporator. When this pressure difference falls, the flow inducing capacity of the eductor is reduced. The flow inducing capacity of the eductor is approximately proportional to the square of the pressure difference. Hence, a pressure difference reduction to 50% of design will lead to an induced flow reduction to 25% of design.

Not all chillers serve the comfort cooling market. There are chillers applied to chemical processes, for example, that may have varying load but constant lift; i.e. constant suction and discharge temperatures. These chillers would not likely have oil loss problems related to load if served by an adequately sized eductor based oil return system.

Possible remedies for poor eductor performance in low lift applications include reducing the oil discharge rate of the compressor/separator and modifying the control system to increase the minimum lift of the system.

Liquid in the Compressor Suction

Ideally, any liquid entering the compressor suction will be rich enough in oil and lean enough in refrigerant that lubrication will be satisfactory. Yet, if any liquid ingested into a compressor has too low a concentration of oil, lubrication may be compromised and wear leading to compressor failure can ensue. All compressors are vulnerable to lack-of-lubrication failure, either from lack of oil or from too much refrigerant in the oil..

A second type of failure is the result of injecting too much liquid refrigerant/oil into a compressor that can damage or destroy the compressor by “liquid slugging”. Screw and scroll compressors are rather more tolerant of liquid in the suction stream than are reciprocating compressors. This is due to the differing nature of the compression processes.

In a reciprocating compressor designed for a three to one compression ratio, the gas may reach the discharge pressure when the piston is only at half stroke. At this point the discharge valve opens and gas is discharged as the piston continues to rise even though gas pressure in the cylinder no longer rises. The final clearance volume may be only one tenth of the total swept volume. This clearance volume is not discharged, but is re-expanded on the suction stroke. One might say at this point that the true compression ratio is ten to one considering a closed discharge valve (swept volume divided by swept volume plus clearance volume). If a volume of liquid of 110% of clearance volume is in the cylinder when compression begins, the piston will be compressing only liquid at the end of its stroke and the liquid may not be able to exit the discharge valve fast enough to avoid developing a very high pressure in the cylinder. This high pressure can cause failure of the connecting rod or failure of the head bolts. For a reciprocating compressor to be efficient, a small clearance volume is required. Yet, it is the small clearance volume that makes reciprocating compressors susceptible to liquid slugging damage. Allowable levels of liquid in the suction are determined by the ratio of clearance volume to swept volume.

In contrast, screw and scroll compressors designed for a three to one compression ratio capture a volume of suction gas (and some oil and maybe some liquid refrigerant) and reduce its volume to one third its original value. But the compression process is completed before the discharge port opens. Any liquid in the suction stream will cause the compression ratio to rise above the design value of three, but the rise is slower than in the reciprocating compressor. For example, assume that the suction stream for a screw compressor consists of 1 part liquid and 8 parts gas by volume. The compressor will reduce these 9 parts to 3 parts. At the completion of compression, one part will still be liquid and two parts will be gas. The pressure in the compressor when the discharge port opens will be four times suction pressure (8 parts gas going in divided by 2 parts gas going out). The one part of liquid remains one part because the liquid is essentially incompressible. Thus, the effect of liquid in the suction stream is to increase true compression ratio. But a four to one true compression ratio in a compressor designed for three to one is probably safe to operate. Allowable levels of liquid in the suction stream are determined by the design pressure ratio and the maximum pressure that can be tolerated in the compression chamber.

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Source by Ed Keuper

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An air conditioning unit is a must-have in any house these days, especially during the summer months. If you are planning to invest in one, then you should have a basic knowledge of the parts and functioning of the appliance to get the most from it. So, when you talk to the service center or are looking up for basic maintenance tips, you will have a clear idea of what you can do.

British thermal unit (BTU)

The cooling capacity of the air conditioner is measured in BTUs. The technical explanation definition of BTU is the amount of energy required to increase the temperature of one pound of water by one degree Fahrenheit. When you check out AC models, (for example Hyundai HY18S3G 3 Star Split AC (1.5 ton) or Voltas 1 Ton 22DYE Split AC), the product specification will give you the capacity details. It is usually mentioned as tonnage (1 Ton= 12,000 BTU/hour).

Duct

It is a pipe used to supply, return or exhaust air. While servicing the air conditioner, you should ensure that the ducts are cleaned and free from any debris or deposits. Any clog in the duct can reduce the performance of your AC.

Diffuser

On top of the ductwork, you can see the diffuser. The function of this small part is to distribute air in the required directions using vanes.

Fans

Yes,there are fans inside the AC unit. These fans are powered by alternating current (AC) and allow for proper air flow inside the cooling appliance.

Condensing unit

This unit of the air conditioner houses the motor, heat exchanger and compressor. It comes as a single unit and usually mounted inside the room with the evaporator set outside the room.

Compressor

This AC part compresses the refrigerant to enhance the performance of the air conditioning unit. There are two types of compressors – screw and scroll. The screw type compressor uses a pair of synchronized screws to compress the refrigerant. In the scroll compressor, one fixed and oscillating screw pressurize the refrigerant.

Refrigerant

It is the actual substance that helps reduce the temperature of the surrounding area. The type of refrigerant used determines the performance, efficiency and eco-friendly factor of the AC. Some of the commonly used refrigerants are water, air, ammonia, carbon di oxide, fluorocarbon compounds and hydrocarbons.

Accumulator

The liquid refrigerant flows back into the accumulator from the evaporator. The accumulator makes sure that the refrigerant doesn’t reenter the compressor.

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Source by Hemalatha Gangadharan