Chiller is one of the most important cooling equipment used in laboratories. The main function of a laboratory chiller is to remove heat from one substance and pass it to other sources like ambient water or air. Chiller is a compressor based equipment that cools and controls the temperature of a liquid unlike the air conditioners, which cools air. Besides compressor the other components of a chiller are a temperature controller, a reservoir and a recirculating pump.

Types of Chillers

The classification of chillers can be done on various basis like portability, working, etc. Here we have classified chillers on the basis of their functioning.

• Air-cooled chillers absorb heat from process water and is transferred to the ambient air. They are mostly used in applications where the heat discharged is not a factor. They don’t need a cooling tower and condense water pump. The maintenance of air cooled chillers are less than water cooled units. However they consume 10% more power.
• In water cooled chillers, heat is absorbed from process water and is transferred to a separate water source like a river, pond, cooling tower, etc. Mainly used at the places where the heat generated by air cooled chillers pose a problem. Due to their less consumption of power they are usually preferred by those seeking optimum efficiency of power consumption.

Functioning of Chillers

The working principle of a laboratory chiller is quite simple. The reservoir is filled with a fluid, typically water or an ethylene glycol/water mix, to be recirculated. The reservoir is connected to the equipment needed and power is provided to the chiller. Chiller’s functions are regulated by the controller. Individual users can set the parameters according to their requirements like temperature, flow and pressure. An internal strainer is used to keep the harmful particles away from the system.

Applications of Chillers

Cooling equipments are used in a number of industries. Some of the most common applications of chillers are:

• Chillers are used to cool the hot plastic in the plastic industry. It cools the plastic that is injected, blown extruded or stamped. They are also used to cool down the equipment used in the manufacturing process.
• In the printing industry, chillers are used to remove the heat generated by the printing rollers. They also help cooling the paper when it comes out of the ink drying ovens.
• Sophisticated chiller are used in the high powered electronics inside the machines like MRI and PET, used in the latest diagnostic tools.
• Chillers cool down the lasers and the source of power supply used to power them.

When the days get longer and the thermometer starts to climb, there is only one thing on most people’s minds, besides bikinis. We are talking, of course, about air conditioning. Like most modern appliances that make our lives easier and more comfortable, air conditioners are something we tend to take for granted.

In this article we are going to take a much closer look at these invaluable machines. We will be paying particularly close attention to how they operate.

Types of Air Conditioners

As you may know, air conditioners are available in various sizes, cooling capacities and prices. Probably the most common kind is the standard window air conditioner. These models are often easy to install, but their cooling power is somewhat limited and so is their overall efficiency.

On the other hand, window air conditioners are still the best way to cool a small space, like a studio or a one bedroom apartment. That is you see them sticking out of the windows of most small apartments.

While window air conditioning units are primarily urban machines, when you pass through the suburbs you will likely find a different kind of cooling device. These are called condenser units, and they are used to run a central cooling system. They are often installed in the backyard and they are far more efficient and thus more inexpensive than window units.

Condensing units are also used to cool most businesses and office buildings. However, instead of installing them in the backyard, there will often be banks of condenser up on the roof.

The final type of air conditioning unit is a cooling tower, which is often only used at enormous office complexes or colleges. These towers are connected to the in house air conditioning system and greatly improve their power and efficiency.

How They Work

In spite of the differences in size and power, all air conditioners follow the same basic rules of operation. And contrary to popular belief, they do not simply pump cool air into your home, office or apartment. What is actually happening is that warm indoor air is removed, cycled and returned as cooler air. This process continues until the room or home reaches the right temperature.

If you need a reference, an air conditioner is really nothing more than a refrigerator without the room to store your food. It relies on the evaporation of common refrigerants, like Freon, to cool warm air. A refrigerator does exactly the same, except, of course, it is used to cool food.

But how does air conditioning actually work? First, the compressor inside the machine compresses cool Freon gas, which causes it to get hot and increases the pressure. The hot gas then passes through a series of coils in an attempt to reduce heat, and afterwards, it condenses into a liquid. The liquid then moves through a special valve where it evaporates and becomes extremely cold Freon gas. Finally, this cold gas moves through another series of coils and in the process it absorbs the indoor heat and cools down the room.