Topic Wise Notes: Hotel Engineering
Please note: The answers provided below, are just for reference. Always consult your college professor if you have any queries.
Q.1. What is LPG? Explain its advantages and disadvantages.
LPG is mostly known as liquefied petroleum gas and is mostly used for cooking in kitchens both domestic and commercial. It’s synthesized by refining crude petroleum or “wet” natural gas. It is a colourless non pollutant fuel.
Liquefied Petroleum Gas is a predominant mixture of Propane (C3H8) and Butane (C4H10).
LPG may be defined as those hydrocarbons, which are gaseous at normal atmospheric pressure, but may be condensed to the liquid state at normal temperature by the application of moderate pressures.
It is normally used as gas but are stored and transported as liquids under pressure for convenience and ease of handling.
Liquid LPG evaporates to produce about 250 times volume of gas.
LPG is odourless and to aid detection of leakages a foul smelling Sulphur-based additive called Ethyl-Mercaptan (CH 3 CH 2 SH) is added.
LPG is denser than air
Advantages of LPG
It contains very less amount of carbon in it, hence LPG powered vehicles produce almost 50% less CO2 than petrol. However, Nitrogen compounds are comparable to Petrol.
It mixes with air at all temperatures.
It provides a uniform charge for combustion, in case of multi cylinder engine.
It has very high compression ratios.
It has very high antiknock characteristics.
Its calorific value is almost 80%, compared to that of gasoline. however, its very high octane number compensates the thermal efficiency.
Researches proves that Using It saves almost 50% of cost than petrol.
The engine may have 50% longer life.
Disadvantages of LPG
It produces 10% less power, compared to petrol, on the same engine.
Its Ignition temperature is higher than that of petrol, it leads to 5% less lifetime of valves.
An efficient cooling system is required, since same is used to provide the heat to the LPG vaporizer (convert liquid into Gas).
Due to heavy cylinders, used to store LPG, weight of the engine gets increased considerably.
A special fuel feed system is required for it.
OR What are the precautions to be taken while using gas?
Make sure your staff are trained to use equipment.
Store gas cylinders as per regulations.
Install and regularly test carbon monoxide (CO) detectors and alarm systems.
Perform regular inspections.
Schedule and record formal maintenance that is carried out by a competent person.
Make sure pipes, storage areas and vehicles carrying gas are suitably marked and signed.
You should also
keep areas around external flue outlets clear including from leaf and paper debris
make sure there is suitable airflow around gas appliances.
Q.2. Draw an organizational chart of maintenance department of a 500 room hotel. List five important responsibilities of a Chief Engineer.
Duties & Responsibility of chief engineer
Planning of manpower requirements
Selection, training and job delegation of maintenance staff
Planning of duty roasters
Planning of smooth distribution of resources such as water, electricity, LPG etc
Planning and maintaining all the equipments and machinery of hotel
Reducing breakdown maintenance time
Improve preventive maintenance procedures
Implement and maintain energy saving plans of hotel
Preparing budget for maintenance department
Preparing work plans in co coordinating with other departments
Q.3. Explain various classes of Fire and also mention types of extinguishers used.
Classes of fire: To make it easier to select the appropriate extinguishing media according to the nature of the material undergoing combustion, fires are arranged in ‘Classes’.
Class A | Wood, paper, textile, rubbish, grass etc. | Water is the best extinguishing medium for Class A. Some Dry Chemical Powder (DCP) are also used. |
|---|---|---|
Class B | Flammable liquids. (Oils, petrol, varnishes, paints, solvents, grease.) | Foam is the best extinguishing medium for Class B fires. Its reactivity should be ensured in case of Chemical fires. |
Class C | Flammable gases | Dry Chemical Powder is widely used for extinguishing gaseous fires. Its ability to cut the chain reaction in the combustion process makes it suitable for the purpose. |
Class D | Burning metal viz. Magnesium, Aluminium, Zinc, | Steam, Dry Chemical Powder be used against metal fires. |
Class E | Fires of electrical origin involving transformers, circuit breakers, switchgears | Dry sand may be used. CO2 type extinguisher to be used. DO NOT USE WATER. |
Class F | Cooking oil, fats (animal and vegetable) | Wet Chemicals to cool and emulsify. |
Types of extinguishers:
Multi-Purpose Dry Chemical (A, B, C)
A dry chemical agent called mono ammonium phosphate. The chemical is non-conductive and can be mildly corrosive if moisture is present. In order to avoid corrosion, it is necessary to scrub and thoroughly cleanup the contacted area once the fire is out. A dry chemical fire extinguisher is usually used in schools, general offices, hospitals, homes.
Regular Dry Chemical (B, C)
A dry chemical agent called sodium bicarbonate. It is non-toxic, non-conductive and non-corrosive. It is easy to cleanup, requiring only vacuuming, sweeping or flushing with water. Extinguishers with sodium bicarbonate are usually used in residential kitchens, laboratories, garages.
Carbon Dioxide (B, C)
Carbon dioxide removes oxygen to stop a fire but has limited range. It is environmentally friendly and leaves no residue, so cleanup is unnecessary. Extinguishers with carbon dioxide are usually used in contamination-sensitive places such as computer rooms, labs, food storage areas, processing plants, etc.
Halotron (A, B, C)
A vaporizing liquid that is ozone friendly and leaves no residue. Because it requires no cleanup, fire extinguishers with halotron are ideal for computer rooms, telecommunication areas, theaters, etc.
Foam (A, B)
Foam floats on flammable liquids to tame the fire and helps prevent reflashes. To cleanup the affected area, it must be washed away and left to evaporate. Fire extinguishers with foam are usually used in garages, homes, vehicles, workshops.
Purple K Dry Chemical (B, C)
A dry chemical called potassium bicarbonate. It is non-conductive and non-corrosive. Clean up requires vacuuming, sweeping or flushing with water. Extinguishers with potassium bicarbonate are usually used in military facilities, oil companies, vehicles, etc.
Water (A)
The most common agent is water; however, it cannot be used for class B or C fires because it is conductive. Water-based fire extinguishers are usually used in stockrooms, schools, offices, etc.
Wet Chemical fire extinguishers (F)
The potassium acetate based agent discharges as a fine mist which forms a soapy foam that suppresses any vapors and steam or the risk of fire reflash as it extinguishes the fire. Class K fire extinguishers can usually be found in commercial cooking areas such as restaurants and cafeterias.
Q.4. What are the different ways in which hard water can be treated for further use?
Remove Hardness of Water (Temporary)
By Boiling:
Soluble bicarbonates are converted into insoluble carbonates which are removed by filtration.
Reactions: Ca(HCO3)2 → ΔCalo3↓ + H2O + CO2
⇒ Mg(HCO3)2 → ΔMgCO3↓ + H2O + CO2
By Clarks Method:
Calcium Hydroxide is Clark’s reagent. It removes the hardness of water by converting bicarbonates into carbonate.
How to Remove Permanent Hardness of Water?
Gan’s Permutit Method:
In this method, sodium aluminum ortho silicate known as permutit or zeolite is used to remove the permanent hardness of water.
Calgon’s Process:
In this method, sodium-hexa-meta-phosphate (NaPO3)6 known as Calgon is used. The hardness in water is removed by the adsorption of Ca++ and Mg++ ions.
Ion Exchange Resin Method:
In this method, the permanent hardness of water is removed by using resins. Ca++/Mg++ ions are exchanged with Cl–, SO4-2 ions are exchanged with anion exchange resin (RNH2OH). Demineralized water is formed in this process.
Q.5. Write short notes on any two: (a) Sensor
A sensor is a device that measures physical input from its environment and converts it into data that can be interpreted by either a human or a machine. Most sensors are electronic (the data is converted into electronic data), but some are more simple, such as a glass thermometer, which presents visual data.People use sensors to measure temperature, gauge distance, detect smoke, regulate pressure and a myriad of other uses. There are two types of electronic sensors: analog and digital. Analog sensors convert physical data into an analog signal. Analog sensors are much more precise than digital sensors, which are limited to a finite set of possible values.
(b) Methods of Waste Disposal
Methods of Waste Disposal
· Landfill
· The Landfill is the most popularly used method of waste disposal used today. This process of waste disposal focuses attention on burying the waste in the land
· Incineration/Combustion
· Incineration or combustion is a type disposal method in which municipal solid wastes are burned at high temperatures so as to convert them into residue and gaseous products. .
· Recovery and Recycling
· Resource recovery is the process of taking useful discarded items for a specific next use. These discarded items are then processed to extract or recover materials and resources or convert them to energy in the form of useable heat, electricity or fuel.
· Recycling is the process of converting waste products into new products to prevent energy usage and consumption of fresh raw materials. Recycling is the third component of Reduce, Reuse and Recycle waste hierarchy. The idea behind recycling is to reduce energy usage, reduce volume of landfills, reduce air and water pollution, reduce greenhouse gas emissions and preserve natural resources for future use.
· Plasma gasification
Plasma gasification is another form of waste management. Plasma is a primarily an electrically charged or a highly ionized gas. Lighting is one type of plasma which produces temperatures that exceed 12,600 °F . With this method of waste disposal, a vessel uses characteristic plasma torches operating at +10,000 °F which is creating a gasification zone till 3,000 °F for the conversion of solid or liquid wastes into a syngas
(c) Air conditioning and refrigeration
Air conditioning is the process of creating and distributing air to control temperature, humidity, and air quality in selected areas. For temperature and humidity control, air is moved over chilled or heated coils and/or a spray of water at a controlled temperature. Direct water sprays also remove dust and odors. Other air cleaning systems may include mechanical separation, adhesion, screening, filtration, or static attraction, depending on the type of air contaminants encountered and the required air quality.
Refrigeration is the process of lowering the temperature of a substance below that of its surroundings and includes the production of chilled water for air conditioning or process applications. Chilled water for use in processes such as injection molding may be in the same temperature range as chilled water used for air conditioning. Refrigeration systems are also used to provide chilled antifreeze solutions (brines) at temperatures below the freezing point of water. Brines are used in icemaking and cold storage, in addition to a variety of chemical process applications.
(d) Base exchange method
Base Exchange softening is a chemical process employed for permanently removing the hardness minerals that cause scale encrustation in hard water. Where appropriately sized and well maintained they will provide ongoing protection against scaling to downstream services and appliances.
Base Exchange softeners utilise an ‘ion exchange’ resin held within a tank to remove positively charged calcium and magnesium ions and replace them with negatively charged sodium ions. The now ‘softened’ water, containing higher levels of sodium, is no longer capable of precipitating hardness minerals into scale. Because of the increased levels of sodium the ‘softened’ water may not meet the requirements for safe potable water so separate untreated mains water supplies should be used to feed drinking water outlets.
Q.6. (a) Discuss the role of fuse in an electric circuit.
It is an over-current protective device with a circuit-opening fusible part that is heated and severed by the passage of over-current through it. A fuse interrupts excessive current (blows) so that further damage by overheating or fire is prevented. Over current protection devices are essential in electrical systems to limit threats to human life and property damage. Fuses are selected to allow passage of normal current and of excessive current only for short periods. A fuse (Kit-Kat fuse) consists of a metal strip or wire fuse element, of small cross-section compared to the circuit conductors, mounted between a pair of electrical terminals, and (usually) enclosed by a non- conducting and non-combustible housing. The fuse is arranged in series to carry all the current passing through the protected circuit. The resistance of the element generates heat due to the current flow. If too high a current flows, the element rises to a higher temperature and either directly melts, or else melts a soldered joint within the fuse, opening the circuit. Fuses act as a weak link in a circuit. They reliably rupture and isolate the faulty circuit so that equipment and personnel are protected. Following fault clearance they must be manually replaced before that circuit may be put back into operation.
(b) What is the role of an insulator in electricity?
Insulators are used in electrical equipment to support and separate electrical conductors without allowing current through themselves. An insulating material used in bulk to wrap electrical cables or other equipment is called insulation. The term insulator is also used more specifically to refer to insulating supports used to attach electric power distribution or transmission lines to utility poles and transmission towers. They support the weight of the suspended wires without allowing the current to flow through the tower to ground.
OR Explain the circumstances under which equipment are replaced.
1. Demand for more number of equipments: This situation arises when the existing number of a particular type of equipment cannot meet the full demand of the hotel. Eg: A bigger DG Set is to be installed as the small DG sets installed earlier cannot meet the full demand and there is no physical space for an additional DG set. Hence the only option is to go in for a bigger DG set.
2. Excessive and frequent maintenance: When the equipment and devices become old, they need frequent maintenance. The frequency of maintenance becomes more and more with the passage of time and more money is spent. Sometimes non availability of spare parts makes maintenance impossible. In such situations, replacement becomes the only option.
3. Advanced Technology Technological advancement is a continuous process and in a short span, we get improved version of the equipment with new technology. Latest technology equipments become an added attraction for guests and customers. Hotels also replace equipments to remain in business competition.
4. Decreasing Efficiency Sometimes with time, old equipments do not give the required efficiency. No amount of maintenance work helps to improve their efficiency.
5. Due to failure Some equipments breakdown all of a sudden.
6. To maintain symmetry Some equipment needs to be replaced to maintain the symmetry.
Q.7. What is Green hotel? What are the different ways to control pollution in hotels?
An eco hotel, or a green hotel, is an environmentally sustainable hotel or accommodation that has made important environmental improvements to its structure in order to minimize its impact on the natural environment. The basic definition of an eco-friendly hotel is an environmentally responsible lodging that follows the practices of green living. These hotels have to be certified green by an independent third-party or by the state they are located in. Traditionally, these hotels were mostly presented as Eco Lodges because of their location, often in jungles, and their design inspired by the use of traditional building methods applied by skilled local craftsmen in areas, such as Costa Rica and Indonesia.
These improvements can include non-toxic housekeeping practices, the use of renewable energy, organic soaps, energy-efficient light fixtures, and recycling programs. It is beneficial for these hotels to get certain certifications in order to be environmentally compliant. One beneficial certification specifically for hotels is the LEED certification. A LEED-certified hotel provides benefits to the environment through energy efficient practices. An eco hotel should follow a set of best practices in order to do their part to benefit the environment. Some of these best practices include serving local organic food in restaurants, reusing linens when a guest is staying for more than one night, and incorporating in-room recycling and composting programs. Hotels that have these certifications and best practices[1] can attract environmentally conscious travelers and stand out from other hotels.
Different ways to control pollution in hotels
Install Energy Saving Technologies.
Embrace Recycling.
Encourage Guests to be Green.
Start Composting.
Save Water.
Plant a Garden.
Support Local, Sustainable Businesses.
Implement Alternative Energy Sources.
OR What are the different types of maintenance? List the advantages and disadvantages of contract maintenance.
Types Of Maintenance
Routine Maintenance
Breakdown Maintenance
Preventive Maintenance
Development Maintenance
Contract Maintenance
Advantages Of Contract Maintenance
Reduction of total labor cost.
Reduction of cost of carrying inventory and special maintenance equipment.
Use of the latest techniques and methods of maintenance.
Saving in administrative time on the part of the engineers when they can concentrate more on planning, etc.
Structure and infrastructural facilities of the in-house maintenance department need not change due to the introduction of new equipment’s with sophisticated technology.
Flexibility to meet emergencies
Reduction of the labor problem.
Need to recruit and train employees are eliminated.
Disadvantages Of Contract Maintenance (Potential)
Labor cost is not really saved unless the actual number of in-house maintenance staff is reduced.
Revision of contract fees in subsequent years often leads to the escalation of total cost if not properly negotiated and controlled.
Often the specialized nature of the maintenance would lead to high charges for such contracts leading to an overall increase in maintenance cost compared to if it were maintained in house.
At the time of bidding, lack of initiative on the part of the Chief Engineer would often lead to a non-competitive price quote by a handful on contractors.
Reduction in the number of specialized in-house maintenance crew may result in their unavailability in case of an emergency requirement for some other facility.
The Chief Engineer does not get any information feedback regarding the status of the equipment under contract maintenance, except in case when it completely breaks down.
Loss of control over contractor employees
Q.8. I Write the full form of the following (any five):
(a) HWC : Handle With Care
(b) BTU : British Thermal Unit
(c) CHU : Celsius heat unit
(d) CVGR : Company volume guaranteed rate
(e) HACCP : Hazard Analysis and Critical Control Point
(g) CFC : Chloro Fluro Carbons
II Discuss care and cleaning of audio-visual equipment in hotels
LCD/ VIDEO PROJECTORS – Care and Maintenance
Projector lens should be cleaned with isopropyl alcohol or a photographic lens cleaning solution. Apply the cleaning solution to cloth and wipe the lens. Never apply the cleaning solution to the lens directly. LCD projectors must be used at temperatures between 5 and 35 degrees Celsius. Dust should be regularly blown off from the lens by means of a blower but from a safe distance.
Care and Maintenance of Computers and its peripherals
Computers and their peripherals are quite robust and reliable. However, casual use of different components, may lead to serious problems ranging from faulty and unreliable operations to complete stoppage of operation. A few routine care and maintenance schedule can ensure trouble free operation for a reasonable period of time. But in case of serious problems, professional help should also be taken.
Care and Cleaning of LCD screens
Utmost care must be taken while dealing with LCD screens. THE DO’S
To remove stains on the screen, properly clean the display surface by gently wiping it with a lint free cloth and glass cleaning agent.
Avoid strong shocks and vibrations.
Be sure to use and store LCD monitors within the specified temperature and humidity range.
The screen should be turned off or brightness should be reduced to prevent ‘burn-in’, which is a permanent damage to certain pixels in the LCD due to overheating.
THE DONT’S
Do not place any heavy object on the laptop.
Do not scratch, twist or hit the surface of the LCD screen.
Do not spray cleaning liquid directly on to the screen.
Do not let moisture accumulate .
Never disassemble the LCD monitor, as the internal backlight assembly can retain a charge of 1000 V and may prove fatal.
LCD screens should not be subjected to sudden temperature change.
Care and Maintenance of Printers
The most common problems faced while using a printer are: poor print quality, streaking print, white lines through prints, no print etc. Most of these problems originate from ink drying up at the print head or nozzle and clogging them during printing operation.
Running the printer at least once a week helps avoid these problem.
Use the printer at least on a weekly basis with both black and white and colour text printing.
Always use printer switch rather than the UPS or Power switch to shut down the unit.
Refilling for colour cartridge must be done with proper ink in the proper chamber.
It is always better to refill an inkjet cartridge before it is empty as the ink of dried up cartridges, if left for too long will clog the print head.
Laser printers should be kept in a dust free area.
UPS – Maintenance and Care
A UPS (Uninterruptible Power Supply) provides instant emergency power to connected equipments by supplying power from a separate source (battery) in case of a failure of the main power supply. The battery is the most important part of the UPS. A periodic maintenance program extends the life of the battery. The following steps can help establish a good maintenance program for he UPS battery. UPS – Maintenance and Care (contd..) Inspection: Periodic inspection should be carried out . Periodic measurements: of the voltage, temperature, resistance etc. should be measured to ensure that the battery is operating to its optimum. Load testing: When the battery can no longer supply 80 % of its rated current, the aging process begins and the battery is considered for replacement. Individual cells of the battery should be monitored, so that only the weak or bad cells can be identified and scheduled for replacement. Record Keeping: All data collected through the above maintenance program should be documented to track the performance of the battery over time.
A Few Good Maintenance Practices for Reliable Operation of Computer Systems
Computer systems are now a part and parcel of modern organizations. Smooth and efficient functioning of the organization nowadays depend a lot on continuous and reliable functioning of the systems.
Switch off computers only after the operating system has properly shut down the computer.
Always use a UPS.
Keep the operating system software and other important utility software in a secured place.
Run scandisk and defragment the file system once a month.
Take regular data backup.
Keep at least 250 MB of C: drive free.
Do not let many programs load up in the computer memory or RAM when the computer starts.
Avoid storing files on the desktop.
Run system file checker twice a month.
Remove all unnecessary files and folders from ‘My Documents’ directory and empty ‘Recycle Bin’ once a month.
Get all critical windows update.
Scan the computer with antivirus at least once a week.
Install firewall protection for Internet access
Clean computer and its accessories on regular basis.
Q.9. Explain vapour compression system of refrigeration.
Vapour Absorption Refrigeration Systems: (VARS) belong to the class of vapor cycles similar to vapor compression refrigeration systems. However, unlike vapor compression refrigeration systems, the required input to absorption systems is in the form of heat. Hence these systems are also called heat operated or thermal energy-driven systems. Since conventional absorption systems use liquids for the absorption of refrigerant, these are also called as wet absorption systems. Since these systems run on low-grade thermal energy, they are preferred when low-grade energy such as waste heat or solar energy is available. As absorption systems use natural refrigerants such as water or ammonia they are environment-friendly. In the absorption refrigeration system, the refrigeration effect is produced mainly by the use of energy as heat. In such a system, the refrigerant is usually dissolved in a liquid. A concentrated solution of ammonia is boiled in a vapor generator producing ammonia vapor at high pressure. The high-pressure ammonia vapor is fed to a condenser where it is condensed to liquid ammonia by rejecting energy as heat to the surroundings. Then, the liquid ammonia is throttled through a valve to low pressure. During throttling, ammonia is partially vaporized and its temperature decreases.
This low-temperature ammonia is fed to an evaporator where it is vaporized removing energy from the evaporator. Then this low-pressure ammonia vapor is absorbed in the weak solution of ammonia. The resulting strong ammonia solution is pumped back to the vapor generator and the cycle is completed. The COP of the absorption system can be evaluated by considering it as a combination of a heat pump and a heat engine
Q.10. Calculate the electricity bill for December 2014 for the following appliances:
Tariff: Rs.5/- per unit
(a) 1000W bulb 10 nos. 8 hrs./day (b) 1.5 KW heater 2 nos. 4 hrs./day (c) 1.5 KW A.C. 1 no. 4 hrs./day (d) 40W tube light 10 nos. 8 hrs./day
Energy used by light bulbs in one day= 1000w*10*8= 80 kwh
Energy used by heater in one day= 1500w*2*4= 12 kwh
Energy used by tubelights in one day= 40w*10*8= 3.2 kwh
Energy used by Ac in one day= 1500w*1*4= 6 kwh
Total energy used in one day = 80 + 12 + 3.2 + 6 = 101.2 kwh
Total energy used in 31 days ( because December has 31 days) = 101.2 x 31 = 3137.2 kwh
1 kwh = 1 unit Cost per unit = Rs 5
Therefore, the bill for the entire month = 3137.2*5= Rs. 15686
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