IQS Newsroom Articles on Liquid Chillers
About Liquid Chillers and Liquid Chiller Manufacturers
Including: Industrial
Chillers, Liquid Coolers, Cooling
Systems, Portable
Chillers, Water
Chillers & Air
Cooled Chillers.
Liquid chillers are refrigeration systems that chill liquids such as water, oil, brine, alcohol, chemicals and beverage or food ingredients for industrial applications. With design and construction very similar to that of air conditioners, liquid chillers range vastly in size and design and may be fabricated as small, localized units for small applications or as large central chillers combining many heat exchangers and external cooling towers which span an entire facility. These industrial chillers cool products, mechanisms and factory machinery in processes such as plastic injection molding, blow molding, metalworking, welding, die casting, chemical and pharmaceutical processing, food and beverage processing, lab equipment, gas cooling and lasers. Chocolate, for example, may be run through a liquid cooler to in order to regulate the chocolate's temperature for the next stage of processing, or to keep it from burning. Water chillers continually cool water which is used in turn to cool laser equipment, while portable chillers and air cooled chillers are used in a variety of facility cooling systems depending on specific design requirements. Liquid coolers are typically recirculating chiller systems which recycle the same refrigerant liquid within a closed loop.
Liquid chillers have four main stages: the evaporator, the vapor compressor, the condenser and the expansion valve. These stages are designed to recirculate the refrigerant through gas and liquid stages. Initially, a cold refrigerant in gas form passes over heat exchanger tubes containing the hot liquid which needs to be chilled. The refrigerant absorbs the heat lost by the liquid, condensing some of the vapor into a liquid. A vapor compressor compresses the liquid-gas refrigerant into a high pressure, high temperature gas. The gas then moves into the condenser coil over which ambient air blows. The air, moved by one or more fans, removes heat from the gas, which causes it to condense into a high pressure, warm temperature liquid. The liquid passes through the expansion valve where a large pressure drop occurs, turning the liquid into a very cold mist. The mist returns to the heat exchanger, and the whole process begins again. Many types of toxic and non-toxic refrigerants may be used in chillers; toxic refrigerants include chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) and halomethanes such as R-22; these substances have very low boiling points, enabling them to change their physical state from liquid to vapor easily. Non-toxic refrigerants include water, brine, liquefied propane gas and CO2.
Four styles of vapor compressors are used: reciprocating, or piston, style compressors; scroll compressors; screw driven compressors and centrifugal compressors. A scroll style compressor uses two interleaved scrolls, one which is stationary and one which rotates about the other to create a pump. A piston style, or reciprocating compressor rotates a shaft that is curved like a crankshaft, creating pressure in the piston cylinder. Screw compressors contain a single rotating screw element which creates a vacuum as it rotates. Centrifugal compressors use inertia to separate vapor molecules from the air. Scroll compressors are usually more efficient than piston compressors, but both are very reliable and widely used in the refrigeration industry. Condensers come in three types. In air cooled condensers, air circulates around tubes containing the refrigerant, contributing to the condensation of the refrigerant. These condensers are used in instances where water is unavailable. Water cooled condensers, also called "shell" or "tube" condensers, utilize water to condense the refrigerant. Water circulates through the tubes around which the refrigerant is introduced, causing condensation of the refrigerant on the outside of the tubes. In evaporative cooled condensers, water is sprayed onto tubes containing the refrigerant. The evaporation of the water causes the condensation of the refrigerant within the tube. Large liquid chillers used for high-volume industrial applications often include a cooling tower at this stage, allowing condensed liquid refrigerant to cool in a tank by various means of air and water cooling.
Halomethanes R-12 and R-22 were the most commonly used refrigerants up until the 1980's, and other similarly toxic refrigerants such as Freon, CFCs and HCFCs continue to be used today. As concern has risen in manufacturing and legislative sectors over global warming, ozone-depleting substances such as Freon, halomethanes and CFCs have been banned or discouraged. Disposal of toxic substances such as Freon is hazardous to the environment, and CFCs used in refrigeration have contributed to significant depletion of the Earth's ozone layer. As the refrigeration and liquid chiller industry advances, more liquid chiller manufacturers are using non-toxic refrigerants such as ammonia, brine and pure water. Centrifugal vapor compressor technology and other types of high efficiency vaporizing coolant systems achieve more efficient cooling physically, without as great a need for low-boiling chemicals.
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Liquid Chillers and Liquid Chiller Manufacturers Image Provided by Tempest
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Types of Liquid Chillers
- ,
the most common chiller type, require little maintenance. However,
because of the need for high condensing temperatures ranging from 120° F
to 140° F, air cooled chillers require more power to operate.
- consist of air handling units fitted
with chilled water coils and are utilized in air condition systems.
- are used to remove heat from an area.
- operate year-round and are designed to
provide specific, capacity-matched cooling protection and proper temperature/water
flow. Dedicated-process chillers are the best choice for medical applications.
- are
uncommon but highly efficient liquid chillers. Evaporative chillers
maintain the lowest condensing temperatures,
which range from 85° F to 105° F.
- provide process cooling using a secondary fluid.
- are often installed outside and are available in centralized
and modular designs. HVAC chillers are used in industrial and commercial
environments.
- are refrigeration systems that are used to chill various liquids in industrial settings.
- are refrigeration systems that remove heat from various liquids.
- lower the temperature of coolant that is used
in the cutting zone and recirculate it back to the machine tool in
a closed-loop
system.
- are self-contained
chillers with higher pressure pumping, temperature stability and microprocessor
controls.
- are self-contained units and are useful in small
and/or dedicated applications.
- constantly circulate coolant in a closed loop,
retaining high efficiency without wasting water.
- consist of a compressor, condenser and chiller with
internal piping and controls all contained within a single unit.
The term "water
chillers" refers also to an overall package that includes a refrigeration
plant, water chiller and air or water cooled condenser.
Common Terms Related to Liquid Chillers and Liquid Chiller
Manufacturers
- The surrounding environment, including
temperature, pressure and/or humidity, coming into contact with a system
or liquid chillers component.
- Mineralized water consisting of sodium chloride, metallic
and/or organic contaminants.
- A measurement unit reflecting the
amount of heat needed to change the temperature of one pound of water
one degree Fahrenheit.
- Tube located between the condenser and evaporator
that manages the refrigerant flow within liquid chillers.
- A chilling system that
are self-contained liquid chillers.
A central chilling system has more than one liquid chiller unit and more than one compressor
but no pump tank set.
- A gas consisting of chlorine,
fluorine and carbon that has been used as a refrigerant in such items
as liquid
chillers. CFCs cause ozone depletion, because they do not break down
upon release into the atmosphere, but mix with ultraviolet light to create
carbon dioxide, and eventually ozone-eating chlorine radicals.
- The
measurement of a refrigeration system's efficiency that compares
the system's cooling ability
with the heat input necessary to attain such cooling. COP is calculated
by dividing a system's cooling ability by the systems heat
input and is expressed in BTU/hr.
- A device that
increases pressure on a gas through the act of pumping. Compressors are
responsible for the compaction of
the vaporized refrigerant to a pressure level suitable for liquification,
which occurs in condensers of industrial chillers.
- A device that removes
heat via forced air, water coil, etc., in order to convert a high pressure
gas into a lower pressure liquid.
Condensers remove heat from the compressed vaporized refrigerant, at
which point, the refrigerant returns to a liquid state.
- The
central part of a refrigeration system in which the system is operated
and maintained.
- A liquid used to remove heat.
- Indicates
the efficiency of an air conditioner, cooling system, or liquid chillers by comparing the
amount of energy needed
to produce cooling with the quality of the system's cooling ability
and is calculated by dividing the system's BTU by its wattage.
For example, if a cooling system maintains 20,000 BTUs and uses 1,500
watts,
the system's energy efficient rating would equal 13.3.
- Consists of a tube inside which the refrigerant soaks
up heat from it surroundings, boils and changes to a vapor.
- Mechanism located between the evaporator and
condenser of liquid chillers that controls the refrigerant flow into the evaporator and
controls the temperature of the evaporator.
- Removes moisture and contaminants from vaporized
refrigerants of liquid chillers.
- A device that
transfers heat from one fluid to another without mixing the fluids. (www.heatexchangers.org)
- A substance containing
chlorine, fluorine, carbon and hydrogen that is used as an alternative
to CFCs
as a refrigerant and a propellant. HCFCs produce fewer effects on than
ozone layer than CFCs do.
- A substance containing hydrogen, fluorine
and carbon that is used to replace CFCs and HCFCs because of HFCs lack
of effect on the ozone layer. HFCs produce no ozone depletion because
the liquid chillers substance does not contain chlorine, which breaks down the ozone
layer.
- A process that utilizes light to cool atoms to
a very low temperature.
- A molecule containing three oxygen atoms that absorbs ultraviolet
radiation in the stratosphere. Ozone also remains a harmful component
of smog and can contribute to lung damage and respiratory problems.
- A relative measurement of a
substance's
negative effect on the ozone layer as compared to the effects of CFC-11,
which has an ODP of 1, on the ozone. For instance, a substance with an
ODP of 2 can potentially cause approximately twice the ozone depletion
as CFC-11 could.
- Also referred
to as the stratospheric ozone, it is the protective atmospheric layer
in the stratosphere, located 12-30
miles (20-50 kilometers) above sea level, in which ultraviolet radiation
is absorbed.
- The storage area for condensed liquid refrigerants
found in most liquid chillers.
- Liquids that produce cooling upon evaporation.
Refrigerants are used in the cooling process of liquid chillers.
- Unit equal to 12,000 BTUs that refers to the
size of the liquid chillers or industrial chillers units.
- A window in a refrigeration system through which
specialists can view the inner workings of the liquid chiller systems.
- Mechanism
in a refrigeration system that controls the flow of refrigerant, especially
into the expansion valve of liquid chillers.
- The
total amount of carbon dioxide that a refrigeration system can produce
throughout its lifetime.