There are many ways to generate hot water in Chicago for domestic purposes, but steam is one of the economic methodologies to generate hot water along with electricity. However, for the installation purposes, you need to understand how the entire system works. One of the significant challenges for MEP engineering is how to create a system that not only uses the steam to the fullest extent but also generate enough hot water for domestic consumption. 

Primary methods of producing hot water using steam

Using steam for hot water production is suited for the commercial and industrial purpose instead of domestic setup because of its high maintenance costs and complex infrastructure. However, overall steam water heating is energy efficient too because with the help of steam you can transfer a lot of heat. There are two primary methods of producing hot water using steam. One is injecting direct steam while the other one is indirect heating of your water.

  • Injecting Direct Steam

This method involves the injection of steam directly into the stream of water. Injecting direct steam is a highly recommended option when you do not wish to retain the steam's condensate. It means the steam is coming from a source of waste, and from here the condensate is not going to be reused under any case. This method can fully recover the latent heat from the condensate along with the condensing heat.

  • Steam Heating Indirectly

It is a simple method of generating hot water that involves the use of a heat exchanger. In this method, steam heats the source of water to a required temperature. The condensate doesn't come in contact with the source, and for this reason, it is known as an indirect method of steam heating.

Tackling the issues associated with using steam for hot water generation

One of the most significant problems that Chicago engineers face is the cost associated with installation and maintenance of the steam heating system. However, with the innovation in this field, many cost-effective techniques have made it easy for the engineers to develop a suitable system for domestic settings.

  • For the adequate distribution of high pressure, correct sized piping should be used.
  • The engineers must set an appropriate number of trap stations within the network.
  • Engineers must adequately install and place these traps along with the equipment for steam conditioning.
  • They must also emphasize on adequately installing vacuum breakers and auto air vents along with the boiler.
  • The boiler must also be easily approachable for maintenance purposes.
  • Engineers must design the system in such a manner that the condensate can return as effectively as possible.

Pipe sizing according to the flow rates

Through the Plumbing and Building Code, the Chicago Department has set the pipe sizing rules and regulations to comply with if you want to use the steam systems for hot water generation.

The Chicago Engineers have to follow these terms and conditions to meet all the legal requirements. By complying with these terms and conditions, the engineers will not only design a safe system but will also make it cost-efficient.

  • Sizing of condensate pipes

The size of the equipment piping according to the condensate load is as follows,

Condensate Load

Pipe Size

200 kg/h

15mm (0.5-inch)

500 kg/h

20mm (0.75-inch)

1000 kg/h

25mm (1.0-inch)

2000 kg/h

32mm (1.25-inch)

3000 kg/h

40mm (1.5-inch)

5000 kg/h

50mm (2.0-inch)

> 5000 kg/h

65mm - 100mm (2.5-inch - 4-inch)

Factors influencing the rate of heat transfer

Various factors influence the rate of heat transfer as well. Primarily, in the beginning, the rate of heat transfer is based on the maximum flow rate from the injector, pipe or control valve but there are other factors too.

  • Steam bubble size

The condensation of the bubble depends on the transfer of heat through the bubble's surface. Make sure that the surface volume ratio is large for full condensation. Small bubbles provide a suitable surface area concerning the unit volume as compared to large bubbles. Therefore, producing small bubbles is desirable for this process.

  • Over injection-point liquid head

Liquid head over the injection point will produce backpressure, and it will reduce the differential pressure as compared to the pressure of steam. If the liquid head is large while the pressure of steam in the pipe is low, a small change will be there in pressure and the bubble size must be small. It will provide the bubbles to condense at a fast rate.

  • Bubble velocity

The velocity depends upon the difference between the liquid head and pressure of steam. The engineers must keep this pressure low which will reduce the velocity of the bubbles as well, and it will give them maximum time for condensation.

  • Liquid temperature

The condensation rate of the steam depends upon the difference of the liquid and steam. Both of these are directly proportional to each other. On the other hand, in the process of heat transfer, the temperature differential is directly proportional to the heat exchange rate.

Conclusion

Using steam systems for generating hot water is highly beneficial for domestic purposes. Some of the traditional models might have been costly. However, innovation and research in this field have provided MEP engineers with an opportunity to design systems that run on steam and are highly efficient. 

It is equally essential for you to understand the rules and regulations set by the Chicago Department so that you can understand how your system is designed and what will be its installation and maintenance costs.

We hope you might have understood the requirements that you must fulfill before you consider a steam domestic hot water generation system.

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