Steam jet refrigeration system - Working/Advantages

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What is a steam jet refrigeration system?

A steam jet refrigeration system is a refrigeration technology that utilizes steam to produce cooling. It works by expanding steam through a nozzle to create a high-velocity jet. This jet entrains and cools a secondary fluid, which is then condensed to remove heat and provide refrigeration.

Also Read: Domestic electrolux refrigeration system – Working, Components

Steam jet refrigeration system components:

Evaporator: The evaporator is responsible for absorbing heat from the surrounding environment, which is transferred to the refrigerant in the system.
Condenser: The condenser is responsible for cooling the refrigerant and converting it from a vapor to a liquid state.
Expansion Valve: The expansion valve is responsible for reducing the pressure of the refrigerant and allowing it to expand, which results in a decrease in temperature.
Nozzle: The nozzle is a restricted orifice that is used to convert the high-pressure steam into a high-velocity steam jet.

Mixing Chamber: The mixing chamber is responsible for mixing the high-velocity steam jet with the refrigerant vapor to cool it down.
Ejector: The ejector is responsible for boosting the refrigerant vapor’s pressure after it exits the evaporator to improve the system’s performance.
Refrigerant: The refrigerant is the working fluid that circulates through the system to provide cooling.
Flash Chamber: The flash chamber is used to separate the refrigerant vapor into two streams, a high-pressure and low-pressure stream, to improve the system’s efficiency.

Steam jet refrigeration System youtube guide:

Steam jet refrigeration system working:

In a steam jet refrigeration system, the system operates by circulating the refrigerant through a series of components, as follows:

Steam is used as a motive fluid to drive the system.
The steam passes through a nozzle, where it expands and produces a high-velocity steam jet.
The high-velocity steam jet is mixed with the refrigerant vapor in the mixing chamber, resulting in a decrease in temperature.
The cooled refrigerant vapor then passes through the condenser, where it is cooled and condensed into a liquid state.
The liquid refrigerant then passes through the expansion valve, where its pressure is reduced, and it expands, resulting in a decrease in temperature.
The cooled refrigerant vapor then passes through the evaporator, where it absorbs heat from the surrounding environment and completes the refrigeration cycle.

Steam jet refrigeration system analysis:

The performance of the steam jet refrigeration system can be analyzed by calculating its coefficient of performance (COP), which is defined as the ratio of the cooling effect produced by the system to the energy input required to operate the system.

Steam jet refrigeration system advantages:

The steam jet refrigeration system is simple in design and construction, which makes it easy to operate and maintain.
It does not require any moving parts, such as compressors or motors, which reduces the system’s maintenance and operating costs.

It can operate using low-grade steam, which can be easily obtained from waste heat sources, such as industrial processes or power generation.
It is an environmentally friendly refrigeration system, as it does not use any ozone-depleting refrigerants.

Steam jet refrigeration system disadvantages:

The steam jet refrigeration system has a low COP compared to other refrigeration systems, which makes it less efficient.
It is only suitable for small-scale refrigeration applications due to its limited cooling capacity.
The system requires a large amount of water for cooling, which can be a challenge in areas with water scarcity.

Steam jet refrigeration system applications:

The steam jet refrigeration system is commonly used in small-scale refrigeration applications, such as air conditioning for small buildings or cold storage for food products.

It is also used in the food processing industry to cool products, such as dairy products and vegetables, during processing and storage.
Additionally, the system can be used in industries that generate waste heat, such as power generation or chemical processing, to provide cooling while utilizing the waste heat as a source of energy for the system.

FAQ – SJRS

1. Why is water used as the refrigerant in a steam jet refrigeration system?

Because under vacuum, water can evaporate at very low temperatures, producing a cooling effect — and it’s cheap, safe, and eco-friendly.

2. Can a steam jet refrigeration system work without a boiler?

Not effectively. It needs a continuous supply of steam, usually generated from a boiler or recovered from industrial processes.

3. Is the steam jet refrigeration system suitable for small-scale cooling applications?

No, it’s mainly used in large industrial plants or central air-conditioning systems where steam is already available.

4. How efficient is the steam jet refrigeration system compared to a vapor compression system?

Its efficiency (COP) is much lower — around 0.2–0.5 — while vapor compression systems typically have a COP of 3–4. However, when waste steam is used, it becomes cost-effective.

5. What kind of maintenance does this system require?

Very little — mainly ensuring there are no vacuum leaks and that the nozzle and ejector are free from scaling or clogging.

6. What is the main reason industries still use steam jet refrigeration despite low efficiency?

Because it can utilize waste steam that would otherwise go unused, reducing operating costs and improving overall plant efficiency.

7. What limits the minimum temperature achieved in this system?

The temperature can’t go below the freezing point of water (0°C) since water is used as the refrigerant.

8. Can a steam jet refrigeration system be used for air conditioning?

Yes, it’s used for central air-conditioning in large buildings, especially where steam is already being produced for other purposes.

9. What happens to the vapor drawn from the evaporator?

The vapor is entrained by the steam jet, mixed with motive steam, then condensed in the condenser, and the condensate is recirculated.

10. How does the steam pressure affect the system’s performance?

Higher steam pressure improves the suction effect and cooling capacity, but also increases energy consumption — so it needs optimization.