Types of Chillers

Chiller Types have been designed to cater to the diversified requirement of industrial chillers.Water chillers have evolved due to the variety in availability of type of energy at industry or small level.Types of chillers have made the use of the chillers flexible in terms of energy input.

Water chillers

Industrial research in the field of chiller has eased the selection of chillers in an economical and robust manner.There is no need of worry whatever type of energy you have available with you.

Each type of chiller targets the specific users classified on the basis of type of energy they have.

HVAC systems employ different types of chillers within the available resources of clients or users.

A chiller may be the best option for particular application while the same chiller may costly or less feasible for another application or plant.

Hvac water chillers are classified primarily on the basis of cycle on which they work.

• Vapor compression chillers or compression chillers or electric chillers
• Vapor absorption chillers or absorption chillers or ammonia chillers or lithium bromide chillers

HVAC chiller types

Vapor compression chillers are further classified on following basis.

• Type of compressor i.e reciprocating compressor,rotory compressor or screw compressor type vapor compressor chillers
• Type of condenser i.e air cooled condenser or air cooled chillers OR water cooled condensers or water cooled chillers

While Vapor absorption chillers are further classified as following:

• Direct fired absorption chillers (Natural gas, Diesel or Kerosene Oil Operated)
• Indirect fired absorption chillers

  
  

   
  

Water Chillers

Water chillers are backbone of HVAC cooling systems.Water chiller is a refrigeration machine which produces chilled water ( Approx 7 Degree C ~ 12 Degree C).The primary function of a chiller is to lower the temperature of water to such value such that it can be used for producing cooling effect in integration with other HVAC components. A water chiller is just like a other refrigerator machine but instead of keeping your food cool or making ice,it produces chilled water.The output of chiller is a water at lower temperature usually around about 10 o C depending upon the Chiller design.

HVAC water chillers play vital role in any HVAC systems along with other basic components. Chillers have got much attention in recent years for its new designs and performance improvement in existing designs. New designs have resulted in hvac chiller with better efficiency and less operation and maintenance costs. Another desirable features is energy saving and precise load or capacity control  for new chillers. We see the chillers with above features in market but as engineering professionals we hope to see more with design improvements with less O & M cost. It is essential part of HVACsystem to have a chiller. Chiller manufacturers have also expanded their production as well design capabilities to cater to the diversified demands of  HVAC chillers.

HVAC Chiller Basics

Working Principle of Vapor Compression Chiller

An HVAC chiller works on vapor compression or vapor absorption cycle.In vapor compression cycle, refrigerant circulates in evaporator ,compressor, condenser and expansion valve of a chiller. A thermodynamic process occurs in each of above chillers.Theoretical working of Vapor compression or compression chillers is explained below.

Heat addition to refrigerant in evaporator ( 1-2):

Refrigerant gets vaporized by taking heat from chilled water in evaporator thus serving its prime purpose. Refrigerant comes out of evaporator as vapors but on other side chilled water is produced. Thus heat is added to refrigerant at constant pressure but is extracted from chilled water. Both refrigerant and chilled water don’t get mixed and are separated by some solid wall in between them in evaporator like shell and tube design.

Compression of refrigerant vapors in compressor (2 - 3 ):

Working Principle of Water Chillers

Refrigerant vapors come out of evaporator and then compressed by chiller compressor to high pressure and temperature. Compressor requires energy input for its working and hence electric energy is supplied to it.

Heat rejection by refrigerant in condenser ( 3 - 4 ) :

Similar to evaporator ,but reverse is happening here. Refrigerant rejects its heat to outside cooling liquid or air .In this way, refrigerant gets condensed and outside media is heated. outside media e.g. cooling water may be cooled by cooling tower and recycled again into condenser.

Expansion of refrigerant in expansion valve ( 4 -1 ) :

Refrigerant in condensed form coming out of condenser is expanded in expansion valve and its pressure and temperature is reduced to level of evaporator so that above cycle is repeated again.

In above four components of hvac chiller ,evaporator is the part where we get chilled water after exchanging heat with refrigerant .

Must Read : Absorption Chillers vs Electric (Compression) chillers

HVAC System

HVAC system is basically an assembly of various types of equipments installed together to provide heating and cooling alongwith indoor climate control. HVAC systems involve mechanical, electrical and I & C components to provide comfort to the occupants of building/space or to preserve goods,products or items placed in space.

HVAC System,HVAC water chillers

HVAC cooling systems may be integrated with HVAC heating systems or these may be installed separately depending upon HVAC design  .HVAC system also serves on industrial scale to keep the machinery running by maintaining the temperature of space/hall/room where machines are installed.HVAC water chillers have become essential for any industry for its various needs.

HVAC System Basic Components

An HVAC System may include the following basic components or units.

• HVAC water chillers and heaters
• Hot water generator (if chiller does produce chilled water only) or furnace
• Chilled water pumps
• Cooling water pumps
• Electrical power supply control or Motor control center (MCC)
• Cooling towers
• Piping for chilled water and cooling water or condenser side water
• Valves for chilled water and cooling water sides
• Air handling units (AHUs) , heating coils and cooling Coils
• Ducts in ventilation system (supply ducts and return ducts)
• Fan Coil Units (FCUs) and thermostats
• HVAC Diffusers and grills
• HVAC controls (instrumentation & Control components)  installed at various locations
• HVAC software for building HVAC control or building management system (BMS)

An Assembly of all above components forms an HVAC system.

HVAC system working principle is explained as below.

In the background of HVAC system ,an HVAC water chiller produces chilled water which is then circulated throughout the building or space upto cooling coils in air handling units.Blowers move air on cooling coils which is then distributed into various portions of space or building for providing comfort or preserving goods/items as per HVAC design.Air is distributed through supply ducts and return air is collected in air handling units with the help of return ducts.Chilled water and cooling water pumps provide energy to keep the chilled and cooling water moving.

HVAC Valves are also installed at various points in piping to ease the maintenance of HVAC system or for the sake of system control.Heating of air may be done with the help of HVAC heat pump ,hot water generator or simply by furnace.Some industrial chillers also serve as heaters in winter season.Heating coils take the place of cooling coils in case of heating mode.

HVAC system cost may vary for different applications as heating and cooling space or environment  varies. Looking for cheap hvac systems may involve little research in types of HVAC systems and HVAC suppliers otherwise you would be lamenting over waste of millions of dollars for selecting wrong HVAC designer & contractor.