What are Deluge Valves?

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What are Deluge Valves?

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Deluge Valves are used in conditions that call for quick application of large volumes of water and, for that reason, are often integral components in fire protection systems. In this article, PIF explain how deluge valves work, what their advantages and disadvantages are, and where you can lay your hands on one. - http://mepsite.blogspot.in/

Deluge systems deliveriitcenter.blogspot.in large quantities of water, over a large area, in a relatively short period of time. They are commonly used in fixed fire protection systems whose pipe system is empty until the deluge valve distributes pressurized water from open nozzles or sprinklers.

Deluge systems contain more components and equipment than wet pipe and dry systems. So for that matter they are more complex. Detection systems can include heat, smoke, ultraviolet (UV), or infrared (IR).

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Applications for Deluge Valves:

Deluge systems are used in conditions that require quick application of large volumes of water. They create a ‘buffer zone’ in hazardous areas or in areas where fires can spread rapidly. They can also be used to cool surfaces to prevent deformation or structural collapse. Or to protect tanks, transformers, or process lines from explosion.


                                    
Other examples include: tanks containing combustible solutions; equipment pits; storage or process areas containing substances with a low flash point; or product handling systems.

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Advantages and disadvantages of Deluge Valves:

Advantages:

1. Less expensive than other methods,
2. Uses water for extinguishing.

Disadvantages:

1. Can damage sensitive or electronic equipment,
2. Longer clean-up time than powder and gas systems,http://mepsite.blogspot.in/
3. Requires a large water reservoir to operate.

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Air conditioning Systems

Selection criteria for air conditioning systems: 

Selection of a suitable air conditioning system depends on: 

1. Capacity, performance and spatial requirements 

2. Initial and running costs 

3. Required system reliability and flexibility 

4. Maintainability 

5. Architectural constraints Q plant Thermal Distribution System 

The relative importance of the above factors varies from building owner to owner and may vary from project to project. 

The typical space requirement for large air conditioning systems may vary from about 4 percent to about 9 percent of the gross building area, depending upon the type of the system. 

Normally based on the selection criteria, the choice is narrowed down to 2 to 3 systems, out of which one will be selected finally.
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Classification of air conditioning systems: 

Based on the fluid media used in the thermal distribution system, air conditioning systems can be classified as: 

1. All air systems 

2. All water systems 

3. Air- water systems 

4. Unitary refrigerant based systems.

All air systems: 

As the name implies, in an all air system air is used as the media that transports energy from the conditioned space to the A/C plant. In these systems air is processed in the A/C plant and this processed air is then conveyed to the conditioned space through insulated ducts using blowers and fans. This air extracts (or supplies in case of winter) the required amount of sensible and latent heat from the conditioned space. The return air from the conditioned space is conveyed back to the plant, where it again undergoes the required processing thus completing the cycle. No additional processing of air is required in the conditioned space. All air systems can be further classified into: 

1. Single duct systems, or 

2. Dual duct systems 

The single duct systems can provide either cooling or heating using the same duct, but not both heating and cooling simultaneously. These systems can be further classified into: 

1. Constant volume, single zone systems 

2. Constant volume, multiple zone systems 

3. Variable volume systems 

4 The dual duct systems can provide both cooling and heating simultaneously.
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These systems can be further classified into: 

1. Dual duct, constant volume systems 

2. Dual duct variable volume systems 

Four Pipe HVAC System

Four Pipe HVAC System:

The system's piping consists of four insulated pipes, two supply and two return lines. One set is dedicated to chilled water, kept between 60 degrees F and 40 degrees F. Another set of pipes is dedicated to hot water, generally kept between 150 degrees F and 200 degrees F. The pipes run to air handlers, which use the chilled or hot water to change the air temperature.

Air Handlers:

• Air handlers in a four-pipe HVAC system can be custom designed to meet a wide variety of heat or cooling demands. They also usually are versatile in that they can be kept in mechanical rooms, on the roof of the building, or with smaller units, in the space above ceilings.

Boilers and Chillers:

• The water in the system runs through two separate systems in order to change the temperature. Cold water is brought down in temperature through chillers, which can be located on the ground or the roof of the building. Chillers come in a wide variety of types to fit different budget and efficiency needs. Water is heated up using a boiler. The boiler is kept either inside or outside. As with the chillers, a number of boiler types are available, for different efficiency and budget needs.
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Advantages Compared to Two-Pipe HVAC:

• The four-pipe HVAC system has a number of advantages over a two-pipe system. Four-pipe systems have separate heating and cooling fan coil units and separate pipes for heating and cooling. This means that hot or chilled water is always available, so the system can immediately change over from heating to cooling mode. Two-pipe systems have to be manually switched over, which is not only inconvenient but time-consuming. Four-pipe systems also can cool some rooms while heating others, offering great flexibility in a building with a variety of heating and cooling needs.

Disadvantages Compared to Two-Pipe HVAC:

• Four-pipe HVAC systems have a number of disadvantages compared to a two-pipe system. They are more expensive to install and maintain and have twice as many valves, coils, controls and pipes to maintain. They also are twice as prone to congestion due to the increased piping.