2734 Serenade Drive
Las Vegas, NV 89100
Memorandum
- Heating System Recommendation
Introduction
In line with your request, I have hereby looked into the matter and came up with the recommendations outlined below. I am glad that we have finally opted to overhaul our hotel’s heating system. This monumental step will not only revamp our customer experience, but also improve our bottom line. I have assessed the technologies used by our competitors and done a bit of research in emerging heating technologies. I am confident to inform you that once the transition is over, we will be the best in the country in this respect.
Although most industry players utilize the fire tube boiler system, I would like to recommend we adopt the water based. As you well know, we are the third largest hotel in this region, our accommodation facilities will not manage if we opt for the former. Our hotel capacity also necessitates the use of a fast heating boiler. These two technologies have their fair share of pros and cons as I will illustrate below.
Characteristics of the Boiler Systems
Fire tube Boilers
Fire tube boiler, gases to heat the water flow inside the piping while the water flows over the heated pipes. This design enables the fire tube boiler to house a large water and steam compartment. The large vessel however limits the pressure of the water tube boiler to 16 bars due to the slow steaming process. Fire tube boilers, despite their relatively small size, require large spaces around them to allow for maintenance. Because the water and steam are stored in the same vessel, the steam quality is low (a bit humid). Due to their low pressure output, fire tube boilers are suitable for relatively small to medium sized establishments.
There are two main designs of fire tube boilers are the dryback or wetback models. The dryback boiler, makes use of a refractory-lined chamber. On the other hand, the wetback boiler uses a water cooled turn around chamber. Both design provide room to circulate flue gases between the furnaces to the tube banks. The wetback design is superior to the dryback one in that it requires less maintenance
Fire tube boilers are available in sizes ranging from 15hp to 1500hp. Their huge variety has resulted in their widespread adaptation. The low initial and operational costs coupled with a lower emission factor, and high turnaround continues to dictate huge sales.
Water tube Boilers
Water tube boilers, on the other hand, are designed to allow water to flow through the pipes as they are heated using hot gases. This ingenious design provides users with the freedom to choose whether they will be used for heating, process or a combination of the two. This ability makes them more suitable for sectors interested in process related uses. Water tube boilers can produce pressure of 100 bars. This high pressure is attributed to the smaller water capacity and hence increased rate of steaming.
Water tube boilers typically have two drums, an upper for drum for steam while the lower drum houses the mud. The two drums are connected through pipes. This structure creates two sections: the furnace and convection section. The main types of water tube boilers are: the membrane water tube boiler, bent tube/flexible boiler and the commercial water tube. The membrane and bent tube boilers are mainly used for heating whereas the commercial one is best suited for steam production for processing (Non HVAC uses).
Membrane water tube boilers are relatively small and thus suitable for low to mid-range capacity establishments. Flexible boilers have a high resistance to thermal shock hence are the most preferred. Commercial water tube boilers produce the highest pressures and quality steam.
Advantages of the Boiler Systems
Fire tube boilers design enables them not only come in smaller and more compact sizes, but also have the ability to hold large volumes of water. This can be advantageous in situations of high demand as there will be insignificant decrease in pressure. Water in a fire tube boiler is heated externally in the furnace, thus normal water that hasn’t been thoroughly cleansed can be used. This improves the efficiency of the boiler. Their design also provides easier access during repair, maintenance or cleaning instances. Lastly because the boilers are suitable in times of fluctuating demand as water can be easily heated or cooled where applicable.
Water tube boilers are fired externally and hence the furnace can be supplemented with low cost energy alternatives like solar. The ability for water tube boilers to provide higher steam pressure (100 bars) makes them suitable for high-rise buildings. The low water capacity also enables water tube boilers to respond to high load demands as they ca heat up quickly. The design of water tube boilers also provides room for one to install a super-heater and thus minimize energy waste. Water tube boilers can also be connected to other modules. This is suitable in situations of high load demands. The quality of steam produced from a water tube is of superior quality as the steam and hot water chambers are separate.
Disadvantages of the Boiler Systems
Fire tube boilers produce less saturated steam as the water and steam are stored in the same container. This also limits the amount of steam pressure to 16 bars. Secondly, there is a high likelihood of having an explosion while using a fire tube boiler as the steam tank is constantly subjected to high pressure. Thirdly, fire tube boilers require plenty of room around them for maintenance purposes. Fourthly, the design of fire tube boilers prevents the use of multiple modules in tandem. Finally, because the boiler is internally fired, there are less options to the energy sources that can be used to heat the water.
Water tube boilers make use of high quality materials. This not only makes them expensive to acquire and but also more costly to maintain when they need repair. Pipes used to supply hot water and steam is also prone to burst due to their high pressures generated. Because water passes through the pipes they require regular maintenance to remove scales. Lastly, water tube boilers also require the use of clean and softer water thus adds to the operational costs.
Best Boiler System
Although the water tube boiler has its fair share of disadvantages such as higher initial costs and costly maintenance, it will be the best option to implement at the hotel. First, the five stories will require a high pressure boiler to supply the heating to the top floors. Second, the high steam quality can be used to run other HVAC systems. Thirdly, the use of super-heaters coupled with the use of the 4-pipe system and alternative energy sources will lower energy expenses. Lastly, because it uses less water, the cost of treating it will be counter-balanced.
- Emerging Technology to Complement the Boiler Systems
Two, the use of hydronic PTACs (Package Terminal Air Conditioners) that have the ability to capture condensate which will reduce energy to be used to preheat cold makeup water meant for the boiler. U-tube heat exchangers can also aid in pre-heating the feed water. Three, more efficient atmospheric or rotary burners can be installed to increase efficiency. These burners can also be programmed to fire at different times
Four, the use of water tube boilers provide ease for implementation of alternative energy. With the increased push towards cleaner and safer energy, our hotel can join the ‘green’ bandwagon. Two or more energy sources can be implemented concurrently to ease the carbon footprint. Solar powered and wind generated coupled with standby generators and backup batteries can supply energy at crucial moments.
Five, variable speed drives (VSDs) can be included in the main feed or deaerator pumps and adjusted where necessary to maximize energy use by ensuring the motors run at the desired speeds. Six, actuators arranged in a parallel position to the heating system’s air supply and fuel valves can go a long way in improving efficiency. Seven, flue gases can also be channeled through economizers to capture the excess heat. This heat that was otherwise being wasted can preheat the feed water entering the boiler. Lastly, using deaerator pumps during water treatment can have the double purpose of heating the water and absorbing many particulates that can result to clogging in the pipes.
- Improvement to the HVAC system
The biggest challenge to heating systems is unwanted heating loads. To regulate loss of excess heat, and thus improve efficiency of the HVAC, our hotel can take a myriad of steps. First and foremost, we can include centralized heating for the conference hall and corridors of all floors. This will go in line with decentralized heating in the hotel units using hydronic PTACs. Condensate drain piping ought to be included to channel the water back to the boilers.
Occupancy sensors and setback thermostats should be installed in every hotel room to ensure the temperatures are maintained at a constant when clients leave. Door closers should be included in less traffic passageways while at the same time using revolving doors at main entrances. This will limit sharp temperature changes that can downplay the ambient atmosphere already created.
Weather stripping of windows and hotel-room doors will also go a long way in limiting temperature variations. Integrated property management systems (PMS) which have become common-place in most industry players. This can be largely attributed to their plethora of uses in management purposes. Apart from monitoring hotel accommodation, personnel and property management, can monitor the maintenance of the heating system. Lastly, hot water from heat pumps, underground tanks or that heated from thermodynamic solar panels can be channeled to the boiler to reduce energy use.
Conclusion
I hope these views will receive a positive approval from our hotel management. For if that is the case, them we are bound to be the leaders in the hotel industry. These recommendations can either be wholly or partly be implemented and still offer our hotel a better chance at besting our competitors. By providing a conducive atmosphere, customer satisfaction and increased business are guaranteed.
Sincerely and Respectfully,
Chief Engineer
Magic Hotels and Resorts
