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Industrial chillers are classified as a refrigeration system that cools a process fluid or dehumidifies air in commercial and industrial facilities. A chiller will use either a vapor compression or absorption cycle to cool. Chilled water has a variety of applications from space cooling to process uses.
A chiller is rated between one to 1000 tons of cooling energy. There are three different types of chillers:(1) air, (2) water, and (3) evaporative condensed chiller. There are four subcategories in each of the above categories for industrial chillers: (1) reciprocating, (2) centrifugal, (3) screw driven (4) and absorption chillers. The first three types are mechanical chillers which are powered by electric motors, steam, or gas turbines. An absorption chiller is powered by a heat source such as steam and uses no moving parts.
The mechanical compression cycle has four basic components through which the refrigerant passes: (1) the evaporator (2) the compressor (3) the condenser (4) the expansion valve. The evaporator in the chiller will operate at a lower pressure and lower temperature than the condenser.
In an ideal cycle, the condenser serves as a two fold component. Before any condensation occurs, the high pressure vapor must be first brought to a saturated condition (de-superheated). Enough heat must be transferred from the refrigerant to lower its temperature to the saturation temperature. At this point, condensation can begin. As heat continues to be transferred from the refrigerant vapor to the air (or water, if a water condenser is used), the quality of the refrigerant (% of the refrigerant in the vapor state) will continue to decrease, until the refrigerant has been completely condensed. In the ideal system, this occurs at the outlet of the condenser. In the real world, some subcooling would be expected at the condenser outlet. Subcooled liquid provides insurance against liquid flashing as the refrigerant experiences pressure losses in the tubing and components.
The refrigerant is in the liquid state now, and at a high pressure and temperature. It must undergo one more change before it becomes a useful heat transfer medium; a reduction in temperature. This is accomplished by reducing the pressure. You can count on the refrigerant’s pressure – temperature relationship to be an infallible law. If the pressure of a saturated liquid is reduced, the law governing its existence requires it to assume the saturation temperature at the new pressure.
So, in order to reduce the temperature, the pressure has to be reduced, and some sort of restriction is required for this to occur. It would be preferable if the restriction could regulate itself as the system load demands change. This is exactly what the thermostatic expansion valve does; it is an adjustable restriction which causes a reduction in liquid refrigerant pressure, yet will modulate in an effort to maintain constant superheat at the evaporator outlet. The thermostatic expansion valve is a superheat control, and will not maintain a constant vapor pressure. It only provides the restriction necessary to reduce the pressure to some level, which will be determined by compressor size, thermostatic expansion valve, size load, load demand and system conditions. If a constant evaporator temperature is required, it can be achieved very simply by maintaining the pressure corresponding to the saturation temperature required. This is accomplished by adding an evaporator pressure regulating valve to the system.
Some of the liquid refrigerant is required to boil as a means of removing the heat necessary to achieve this lower temperature. Yet another heat transfer process, which yields a lower liquid temperature. The liquid that is sacrificed in the boiling process explains the increase in refrigerant quality. The greater the difference between the liquid temperature and evaporator temperature, the more liquid will have to be boiled in order to achieve the new saturation temperature. This results in an even higher refrigerant quality.
The final portion of the refrigerant’s journey is as a mixture of saturated liquid and vapor, traveling through the evaporator tubing. Warm air is blown across the evaporator, where its heat content is transferred to the boiling refrigerant. This is a latent heat gain to the refrigerant, causing no temperature increase, while experiencing a change of state. In the ideal cycle, the last molecule of saturated liquid boils off at the evaporator outlet, which is connected to the compressor inlet. Hence, the vapor at the inlet of the compressor is saturated. The cycle continues this way until the refrigerated space temperature is satisfied, and the equipment cycles turns off.
Over the past 73+ years Coles Refrigeration and Air-Conditioning have maintained their reputation as Newcastle’s leading air-conditioning and refrigeration company by ensuring their staff have the products, knowledge, expertise and experience to create efficient and reliable air-conditioning systems tailored to your specific requirements.
Contacting Coles refrigeration and Air-conditioning to organise a consultation with a sales engineer will ensure your system is able to meet all of your requirements in the most practical and efficient way. This process is obligation free, free of charge and will provide you with not only a detailed quote but also honest valuable advice from recognised air-conditioning experts with decades of experience.
“I just thought I would share some feedback with you on this very hot day. In the past, our air conditioning has always struggled badly on these hot days.The guys out the front (with glass windows) would be sweating and they would turn the air right down. The people in the back of the office would need to bring jumpers and cardigans to work on a day like this. BUT NOW – AFTER YOUR TECHNICIAN WAS HERE LAST MONTH. It’s fantastic. We have been in this building for 10 years and the air conditioning has never worked better!! So thank you to everyone there for making that happen for us. We are all very happy and have been mostly unaware that it’s even a hot day out there. We love it!!”
“Your professionalism, quality, honesty, and delivery timeframes were outstanding given you were under an extremely tight schedule to get the project completed. I was especially impressed with your effort to accommodate any additions to the original scope, including the client's request to refurbish the entire kitchen two weeks prior to Christmas. I have no hesitation in recommending you and Coles Refrigeration & Air Conditioning to future clients and trust we will continue to further strengthen the relationship between our companies.”
“Coles have been responsible for the provision, installation and servicing of all our beverage and catering equipment, air conditioning & general refrigeration. I have conducted business with Coles since 1994. I have no hesitation in recommending Coles Refrigeration & Air Conditioning to prospective clients.”
“We were impressed by the excellent sales advise, design, installation and after sales service we received. All equipment restoration was carried out professionally keeping costs to a minimum. Coles Refrigeration & Air Conditioning ensured that our budget was met and that we received the best available equipment within that budget. For future requirement, we will not hesitate to involve Coles Refrigeration & Air Conditioning. Thank you for the professional input and service!”
“Thank you for the excellent work produced by your staff during the fit out of our new kitchen. The stainless steel exhaust and benchwork are second to none. Our cool room, pantry and freezer are working beautifully and the shelving and the layouts are exactly to our requirements. I will always be available to be contacted to recommend the work you and your staff did on our new kitchen.”
“Throughout all the stages of development and construction, I always found the staff from Coles to be highly professional and diligent in their works. Cole's tradesmen who carried out the works at our site were always helpful and met our stringent OH&S requirements. The buildings that were refurbished present various challenges with timeframes and meeting relevant codes and standards. With Cole's help, we were able to meet and exceed all expectations. I have no hesitation in recommending Coles Refrigeration for any future works in which they tender.”
“Mitchel Cousins has presented at two workshops held by the Energy Hunter team, helping businesses gain an understanding of real life ways to improve performance, reliability and cost savings of plant and equipment. Mitchell displayed high level of knowledge in both his specific industry, as well as energy efficiency. It was a pleasure working with Mitchell and I would happily do so again.”
“I was on site this morning at 47 Darby Street for the RMS Fitout project, and the foreman was heaping a fair bit of praise on you guys for the quality and speed of work! Thanks for helping us out on this one.”
Unit 1 / 3 Concord Street Boolaroo NSW 2284
Phone: (02) 4957 0221
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