എത്രമാത്രം വ്യത്യസ്തമാണ് വീടുകളിലെയും ഷോപ്പിങ് മാളുകളിലെയും കൂളിംഗ് സിസ്റ്റം

                                        

                                        CHILLERS

Heating, ventilation and air-conditioning systems regulate the comfort levels of many indoor environments. A chiller plant is a centralized system that cools the air for a building or for a collection of buildings and provides the air-conditioning portion of HVAC systems. According to the federal government's Energy Star website, over 35 percent of buildings larger than 100,000 square feet contain chiller plants.

In most process cooling applications, a pumping system circulates cool water or a water/glycol solution from the chillers to the process. This cool fluid removes heat from the process and the warm fluid returns to the chillers. The process water is the means

by which heat transfers from the process to the chillers.

Process chillers contain a chemical compound, called a refrigerant. There are many types of refrigerant and applications depending on the temperatures required but they all work on the basic principle of 

compression and phase-change of the refrigerant from a liquid to a gas and back to a liquid. This process of heating and cooling the refrigerant and changing it from a gas to a liquid and back again is the refrigeration cycle.

The refrigeration cycle starts with a low-pressure liquid/gas mix entering the evaporator. In the evaporator, heat from the process water or water/glycol solution boils the refrigerant, which changes it from a low-pressure liquid to a low-pressure gas. The low-pressure gas enters the compressor where it is compressed to high-pressure gas. The high-pressure gas enters the condenser where ambient air or condenser water removes heat to cool it to a high-pressure liquid. The high-pressure liquid travels to the expansion valve, which controls how much liquid refrigerant enters the evaporator, thereby beginning the refrigeration cycle again.

There are two types of condensers used in chillers; air-cooled and water-cooled. An air-cooled condenser uses ambient air to cool and condense the hot refrigerant gas back down to a liquid. It can be located inside the chiller or can be remotely located outside, but ultimately it rejects the heat from the chiller to the air. In a water-cooled condenser, water from a cooling tower cools and condenses the refrigerant.

Energy Efficiency

The Department of Energy estimates that 10 to 15 percent of the energy consumed by buildings is used for air-conditioning. Though the efficiencies of condensing units are continuously improved, more energy can be saved by improving distribution systems and reducing overall plant size. A large degree of cooling is lost as air moves through the ductwork in a building.

The faster and more efficiently air moves, the less cooling it looses. Moving air also looses pressure to leakage in the duct system, which requires fans to work harder to move air through the building.

Operations and Maintenance

Another way to save energy in chiller plants is through operations and maintenance. Today, many systems connect to centralized controls that can automatically adjust output to maintain the most efficient operations. Keeping mechanical units functioning at full

capacity requires periodic maintenance, such as changing air filters or replacing belts and gaskets.

reference : 

https://www.ehow.com/info_12044133_chiller-plant.html