The primary function of the desuperheater is to lower the temperature of superheated refrigerant or other vapors in process. This temperature reduction of gas is accomplished as a result of the refrigerant being brought into direct contact with other liquid called water. The sprayed water is then evaporated.
Basic Desuperheating Theory
Superheated refrigerant is gas that is at a temperature that is higher than the normal temperature, at the superheated level. This extra heat is wasted in atmosphere which:
• Is higher than saturation temperature.
• Contains more energy.
• Has a greater specific volume than saturated gas.

If the gas is too hot, it will cause equipment (condenser) to damage and hence the condenser efficiency is decreased.
The overall purpose of a desuperheater water heater is to provide effective heat transfer between refrigerant and water. And a highly effective desuperheater water heater design and application results in costly problems to be avoided, including extended shutdown and startup times.
Desuperheaters water heater comes in a variety of configurations including probe style with variable or fixed nozzle, double venture and venturi. With a design that has finely controlled water spray that results in reducing refrigerant temperature at saturation level.
A desuperheater is a device that cools superheated gas to a temperature close to its normal temperature, typically by spraying fined droplets of water into the flow of supeheated gas. Superheated gas is gas that is at a temperature above its normal temperature.
Desuperheater Installation:
The Desuperheater Water Heater is installed before the condenser and the oil separator. The refrigerant gas goes through a number of tubes in the Desuperheater water heater before entering the condenser section. Normally the Desuperheater Water heater is designed especially for the hot water requirement. When requirements of the hot water & refrigeration cycle are not parallel, a "Recirculation" type mechanism is provided in which hot water is generated, stored and maintained without leak in an insulated tank. This hot water then can be utilised as and when required.
The Desuperheater water heater can be easily retrofitted on reciprocating, scroll or screw type chillers.
There are two types of refrigerants on which desuperheaters operate
1) Freon Desuperheater.
2) Ammonia Desuperheater.
1) Freon Desuperheater: Maniks desuperheater works on freon refrigerant gas to extract the superheated refrigerant and use it for other purposes. Therefore this heat if used for boiling water in hotels, restaurants etc users can get free of cost water.
2) Ammonia Desuperheater: Ammonia is the oldest one of all the refrigerants and it is still widely used in the refrigeration and air conditioning applications. It is also the only refrigerant outside the halocarbons group, still being used to a great extent.
Ammonia is less expensive and used as refrigerant largely in the many refrigeration systems of food industry like ice creams plants, dairies, cold storage warehouses, frozen food and production plants, processors of poultry, fish and meat and many other applications. Maniks desuperheater works on ammonia refrigerant gas to extract the superheated refrigerant and use it for other purposes. Therefore this heat if used for boiling water in hotels, restaurants etc users can get free of cost water.
Desuperheater Applications:
The Desuperheater can be found in different types of applications, including:
1) Power generation
2) Process controllability
3) Thinner pipe and lighter flanges
4) Preventing lubricant degradation
5) Protecting downstream equipment
6) Gas desuperheaters
Power generation
Boilers running at minimum loads or with high power, produce variable temperature gas. Desuperheaters are used to stabilize superheat over wide range of flows.
Surface condensers work most effectively when supplied with saturated gas. This reduces the need to add tubes for cooling the superheated gas, and prevents burden caused by thermal expansion whenever the hot, dry refrigerant gas enters the condenser.
Process controllability
Desuperheaters also help to control a variety of processes. If working refrigerant temperature is not constant, a process becomes uncontrollable, especially when gas flow or pressure changes continuously. This impacts product quality and cost, force unscheduled error, creates personnel safety problems, and cost a greatly in repairs and replacements.
Thinner pipe and lighter flanges
Cooler gases requires thin pipe schedules or lighter flange than superheated gas. Besides from lower costs, this can reduce down- times for piping, controls, valves and other equipments during their initial constructions or shutdown maintenance.
Preventing lubricant degradation
Superheated gas may immediately degrade certain lubricants, so the saturated gas is utilized for expensive special items such as compressors and pumps.
Note: Even if you have installed a water heater such as solar system in your Hotel for Hot water generation, the manufacturer of Solar System provides you with “Back up” electric heaters installed in the Hot water tank. These electric heaters gets automatically switched ON when the temperature of water falls below 40 ° C. Typically most of the hot water that is produced by the solar water heater system gets consumed by 11 PM, when your Guests takes bath on return to your Hotel. Therefore to meet the Hot water requirements for the "Morning peak hours from 6 am to 10 am, electrical water heaters have to be switched ON at 4 AM and kept ON till at least 10AM".
This adds up to your Electricity Bills, "Without you releasing it". HENCE EVEN IF YOU HAVE THE SOLAR SYSTEM FOR HEATING WATER INSTALLED AT YOUR HOTEL, DESUPERHEATER WATER HEATER WILL CONSIDERABLY REDUCES YOUR ELECTRICITY BILLS.