There are many ways to generate hot water in Chicago for domestic purposes, but steam is one of the economical methodologies to generate hot water along with electricity. However, for 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 utilizes steam to the fullest, but also generates enough hot water for domestic consumption.
Primary methods of producing hot water using steam
Using steam to produce hot water is suitable for commercial and industrial purposes rather than domestic installations due to its high maintenance costs and complex infrastructure. However, general steam heating of water is also energy efficient because with the help of steam you can transfer a lot of heat. There are two main methods of producing hot water using steam. One injects steam directly while the other indirectly heats the water.
- Injecting Direct Steam
This method involves injecting steam directly into the water stream. Direct steam injection is a highly recommended option when you do not want to retain steam condensate. It means that the steam comes from a waste source and from here the condensate will not be reused under any circumstances. This method can fully recover the latent heat of condensate along with the heat of condensation.
- 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 water source to the required temperature. The condensate does not come into contact with the source, which is why it is known as the indirect method of steam heating.
Addressing the problems associated with using steam to generate hot water
One of the most significant problems Chicago engineers face is the cost associated with steam heating system installation and maintenance. However, with innovation in this field, many cost-effective techniques have made it easier for engineers to develop a system suitable for home environments.
- For proper distribution of high pressure, correctly sized piping must be used.
- Engineers must define an appropriate number of trap stations in the network.
- Engineers must properly install and place these traps along with steam conditioning equipment.
- They should also emphasize the proper installation of vacuum circuit breakers and automatic air vents along with the boiler.
- The boiler must also be easily accessible for maintenance purposes.
- Engineers must design the system in such a way that condensate can return as efficiently as possible.
Pipe sizing according to flow rates
Through the Plumbing and Building Code, the Chicago Department has established the pipe sizing rules and regulations to comply with if you want to use steam systems for generating hot water.
Chicago Engineers must follow these terms and conditions to meet all legal requirements. By complying with these terms and conditions, engineers will not only design a safe system but also make it profitable.
- Dimensioning of condensate pipes
The equipment piping size according to the condensate load is as follows,
|
Condensed Charge |
Tube size |
|
200kg/h |
15 mm (0.5 inches) |
|
500kg/h |
20 mm (0.75 inches) |
|
1000kg/h |
25 mm (1.0 inch) |
|
2,000 kg/h |
32 mm (1.25 inches) |
|
3,000 kg/h |
40 mm (1.5 inches) |
|
5,000 kg/h |
50 mm (2.0 inches) |
|
> 5,000 kg/h |
65 mm – 100 mm (2.5 inches – 4 inches) |
Factors influencing heat transfer rate
Several factors also influence the rate of heat transfer. Mainly, in the beginning, the heat transfer rate is based on the maximum flow rate of the injector, tube or control valve, but there are other factors as well.
- Vapor bubble size
Bubble condensation depends on heat transfer across the bubble surface. Make sure the surface volume ratio is large for full condensation. Small bubbles provide adequate surface area to unit volume compared to large bubbles. Therefore, the production of small bubbles is desirable for this process.
- Liquid head above the injection point
The pressure of the liquid over the injection point will produce back pressure and reduce the differential pressure compared to the vapor pressure. If the head of the liquid is large while the vapor pressure in the tube is low, there will be a small change in pressure and the bubble size should be small. This will cause the bubbles to condense quickly.
- Bubble speed
The speed depends on the difference between the height of the liquid and the vapor pressure. Engineers must keep this pressure low, which will also slow the bubbles down and give them maximum time for condensation.
- Liquid temperature
The rate of vapor condensation depends on the difference between the liquid and vapor. Both are directly proportional to each other. On the other hand, in the heat transfer process, the temperature differential is directly proportional to the heat exchange rate.
Conclusion
The use of steam systems to generate hot water is highly beneficial for domestic purposes. Some of the traditional models may have been expensive. However, innovation and research in this field has provided MEP engineers with the opportunity to design systems that run on steam and are highly efficient.
It is equally essential that you understand the rules and regulations set forth by the Chicago Department so that you can understand how your system was designed and what your installation and maintenance costs will be.
We hope you understand the requirements you must meet before considering a steam domestic hot water generation system.
