Category Archives: Hotel Engineering

Old thinking vs. New technologies

Old Hotel Phone

Old Hotel Phone

             There was a time when telephones were only available to the elite. As such, it was strictly the most upscale hotels that made use of phones during the late 1800s and early 1900s. Typically, a desk phone would have been available for hotel staff, and a single wall phone located in the lobby area for guest use, with all calls being directed through an outside operator.

        In 1957 Hilton first offers direct-dial telephone service in Hotel. This allowed  rooms to dial out local calls and be billed for them.Another feature was single digit dialing for various services–room service, valet, concierge, front desk, each would have a single digit assigned to them and the phone dial would have an outer mount explaining all this.For long distance calls, hotel operators would ask for time and charges (as most businesses did back them), record them, and add them to the guest’s bill.


Although still considered to be a luxury, this became a turning point for phones within the hospitality industry. As guests could now connect directly to other guest rooms, the front desk, and outside lines, the demand for in-room phone extensions was growing. Over the following decades, the popularity of both residential and commercial telephone systems exploded, enabling hotels to take advantage of the service for accepting advance reservations.
Guest Room Phone
        The next major change occurred in the 1960s, when touch-tone telephones were introduced. Not only did this improve dialing speed, but the technology also made automated phone menus possible. As technology progressed, hotels enjoyed the luxuries of caller ID, multiple phone lines, call waiting, call transfers, and more.
The biggest breakthrough for hotel phone systems came with the launch of the World Wide Web. Although, at the time, many traditional phone companies argued that voice would never be able to travel via the internet, the idea was never abandoned, and as early as 1995 the “Internet Phone” was born. It took nearly a decade to perfect this particular technology, with the world’s introduction to Skype in 2003 as the big game-changer.
At present, hotels and guests has shifted to the Handheld Android Devices and I-pad, I-Phone, etc.


                Fuel is any substance capable of chemical combustion with oxygen producing heat and light.

                Calorific Value: number of heat units produced by complete combustion of unit quantity of fuel.



                WOOD: Good domestic fuel. In industry may be used for Boiler furnace. Contain large amount of moisture, has low thermal value. Calorific value around 4,700 Kcal/kg.

                Coal: most extensively used solid fuel, used for both industrial and domestic purposes. Average Calorific value is 7,750Kcal/kg.

                Coke: Mainly used for domestic purpose. Has higher calorific value.

LIQUID FUELS: are petrol, kerosene, diesel oil etc.

Points in their favour are:

1.       Combustion control easily.

2.       Require less storage space.

3.       Relative cleanliness.

Used to great extent for I.C. Engineers but to lesser extent for steam raising purpose.

GASEOUS FUELS: may be natural or manufactured.


  1. can be easily transported

  2. combustion control effective

  3. smoke and ash eliminated

Calorific value:

  1. Coal gas – 5,000 Kcal/m3

  2. Cake Oven – 4,000 Kcal/m3

  3. Producer Gas – 1,400 Kcal/m3

  4. L.P.G. – 722 Kcal/m3

L.P.G.: liquid petroleum Gas contains methane, propane, butane etc. gases as constituents. On applying pressure to this mixture of natural gas, a liquid mixture of gas obtained and this liquid is known as L.P.G. Calorific value of this is higher than that of natural gas obtained from oil walls. Therefore, it is a better gaseous fuel.


Calculation of fuel amount and its cost:

                In hotels, various fuels may be required. Amount of solid fuels are measured by their weight and Liquid fuels, gaseous fuels and electric energy through meter.

                By knowing amount of fuels used during a period, say a month and then by knowing the unit cost of fuels the fuel cost for a month may be found and thus average expenditure on fuels in hotel can be calculated.

                Let us take simple example regarding cost of fuel in the catering section of a hotel.

                Say in a hotel 120-gas cylinders used average per year in catering section. Cost per cylinder is Rs. 200/-.

                To determine average cost of gas fuel per month for said catering section-

Cost of gas fuel for one year = 120 x200 = Rs. 24,000

Per month 24000/12 = Rs. 2000/-


Fuel cost economy:

To keep the cost at economic level in catering industry the kitchen energy saving will play very important role. Few tips given below in this regard.

  1. For food disposer it is better to use cold water instead of hot water. That saves fuel required for hot water. Greased solidify in cold water, can be ground and washed easily.

  2. Kitchen sink faucet may be fitted with aerator to reduce hot water flow and save fuel for hot water.

  3. Gas burner needs burn with blue flame. Has to be cleaned time to time.

  4. Water to be boiled in kettle or covered pans in place of open ones.

  5. Matching the size of pan to heating element will reduce heat lost to surrounding air.

  6. In case of oven-cooked meals, it is better to cook as many dishes as can be managed at a time.

  7. In case of cooking food with electricity, the burners are to be turned off several minutes before necessary cooking time as heating element will stay hot long enough of finish up cooking and that will save electricity.

  8. Not to open oven doors often to check food inside.

  9. To use small pans or ovens for small meals.

  10. Use of pressure cooker and microwave oven can save fuel.



Heat terms and units, method of transfer:

Heat: is a form of energy. Can be converted to other forms of energy i.e. steam, mechanical etc.

Temperature: indicates “hotness”. Is a measure of intensity of heat.

Heat units: B.T.U. (British thermal unit)

                C.H.U. (centesimal heat unit)

                Cal (Calorie) etc.

1 Kcal = 2.21 CHU = 3.97 BTU.

1BTU = 0.556CHU = 0.252 Kcal

Heat transfer: can be transferred by Convection, Conduction and Radiation.


Principles of Bunsen burner:

                It was Robert Bunsen, a German chemist who introduced the burner. It works on the principle on which gas is now used in stoves and lights. By arranging more supply of air to the gas fuel perfect combustion resulted inside the burner. The non-luminous flame of burner is the outside edge of the outer cone.

High and low, pressure burners: Burners may be of high and low pressure gas supply type. Maximum pressure is 14 inches water column pressure. Heat output depends on pressure.

                Low pressure: 4-inch water column. Equivalent to 18,000 BTU/ hr.

                High pressure: 10 inch water column. Equivalent to 16,000 BTU/hr.

Therefore, low-pressure burners out put more than high-pressure ones.

Precautions to be taken while handling gas:

                Obviously one has to be careful in handling gas fuel. The valves fitted in pipes and tank must be operated in rational manner. When fuel not in use these valves must be kept closed. Leakage of gas in any manner is dangerous. Flame and fire to be kept at safe distance. Abnormal odour to be verified as soon as possible. Pressure regulator function to be observed, tested, and replaced when necessary.


Fuel tanks, location, manifold types:

                Oil fuel tanks may be inside or outside the building. Outside tanks are located underground.

                Normally following procedure of installation to be maintained for fuel oil tanks-

  1. Tanks installed as close as possible to the inside wall, either at front of building or at the side adjacent to drive way for allowing easy access for filling of fuel.

  2. Tank to be located to provide for shortest possible pipe connection, from tank to burner, but at the same time it must not be less than minimum distance required from burners or source of any other fire or flame.

  3. Tank to be provided for shortest fill connection as far as practicable.

Manifold: firing end of burner consists of gas manifold assembly (for gas burners) that includes the mounting flange for the whole burner. The assembly can be rotated 120O to provide for right or left hand entrance.

                It is to be noted that if gas tank installed outside then these to be underground installations talking all safety measures against fire and undesirable explosion danger. Water spray arrangements should be provided to prevent excessive heat of summer, which may cause explosion.




                Electricity is form of energy, which is capable of doing works, e.g. lighting lamps, producing heat, driving machines, operating television-radio-communication systems etc.

Electrical conductors: materials, which allow flow of electricity, are conductors of electric. E.g. silver, copper, aluminium, iron, earth, human body etc.

                Insulators: materials that put resistance to flow of electricity are called insulator. E.g. porcelain, ebonite, glass, rubber, wood, mica etc.

                Current: rate of flow of electricity or in simple electricity in motion. Unit used ampere and is measured by instrument ammeter.

                Potential difference: the terminal from which electric currents tends to flow is positive (+) one, while the terminal to which current tend to flow is negative (-) one. So positive terminal is at higher potential, potential indicates “electric pressure”. The difference between higher and lower potential is called potential difference which is expressed by term “Volts”, measured by “voltmeter”.

                Resistance: is the opposition offered by conductors to the flow of electricity. Units in “ohms” and measured by “ohmmeter”.

                Work: when an object is moved against force, work is said to be done, measured by ‘Force x Distance’.

                Power: is rate of doing work. So power = work/time. Electrical unit of power is watt. Power = EI watts where E = Volts, I = Amperes (Amps). 1 Horse Power (H.P.) = 746 watts=3/4 Kw. 1 K.W. = 1.33 H.P.

                Energy: means capacity to do work, during certain time. Electrical energy unit- K.W.H (Kilowatt hour) is energy supplied in one hour by an electrical circuit, which is measured by Energy meter.

A.C. and D.C. Current:

                A.C. means alternating current and D.C. means Direct current.



                When conductors is moved in a magnetic field so that the conductor cuts the magnetic lines of force then E.M.F. (electro magnetic force) or say electrical pressure is generated in the conductor, which can cause flow of electrical current in it. Actually the E.M.F. produced is alternating type direction wise. So the A.C. current direction wise (in alternating manner) is produced in the external electrical circuit.


                The alternating current can be made to flow in same direction by connecting a device called “commutator” in the circuit. Then the current produced is known as D.C. (Direct Current).

                Phase: it has reference to the manner the winding is made in A.C. machines. We say A.C. machines to be single phase, two phases, three phases etc. if they are wound with single, two or three phase winding respectively.

                Alternators (generators producing alternating current) are usually of single or three phase. Three phases gives greater power at less cost than single phase for the same size.


Advantages of A.C. over D.C.:

  1. Simpler generating machine.

  2. Economy in transmission of electrical energy over long distances.

  3. Voltage can be raised or lowered by using transformers.

  4. By raising the voltage, the current is reduced for transmission of a given supply of energy and so the size of conductor is reduced and thus economy is affected.


Load on single and three phase supply:

                Most of the domestic loads like light, fan, fridge, iron, heater, oven, washing machine etc. run on single phase supply.

                In case of houses/buildings when load demand is high three phase connection made to distribute loads equally amongst the supply phase and this will effect less voltage drop in the load circuits. When voltage around 440v required for loads, this type supply is necessary.



                D.C. generator specification is given in term of volts, current, kilowatt, speed etc. provided in name plate.

                In case of A.C. generator these are volts, phase, frequency, K.V.A., current, speed etc.


Electric circuits:

                The electric current path is called electric circuit. When current flow is interrupted the circuit is open circuit. Other wise it is closed circuit and hence electric current flow exists.

                When there occurs any connection in between a closed circuit there is short circuits in the system.

Circuit element symbols:

  • voltage – V or E,

  • Resistance – R,

  • Current – I,

  • Ohms law – I=V/R or E/R

  • Resistance

  • Fuse

  • Earth connection

  • Switch

  • Two way switch

  • Battery


Reason of placing switches on the Live wire.

                If the switch is on ‘N’ wire (Neutral wire ) the use of lamp is not safe as even if the switch is off then also the current is there to the lamp unit, hence repairs or replacement works are unsafe. But if the switch is on ‘L’ wire (Live wire) the use of lamp is safe, as if the lamp is not in use, or needs repairs and the switch is off, then there is no current in the lamp fitting.


Electric wires and types of wiring:

                Electric conductors are termed as wires and cables. Mainly two types of wires – (i) Bare wire, & (ii) Insulated wire.  Bare wires are used for overhead transmission and distribution of electric energy. Insulated wires and cables are used for indoors and underground connection mainly.

                The types of insulated wires are (a) lead covered, (b) vulcanized India Rubber (VIR), (c) Tough Rubber Sheathed (TRS) or Covered Tough Sheathed (CTS), (d) Polyvinyl chloride compound wire (PVC), (e)Weather proof wires (f)flexible wire, (g)Insulated cable wire etc.

Wiring types:


1.       Cleat wiring. It is VIR wire in porcelain cleat,

2.       Casing capping. VIR wire in wooden casing,

3.       TRS or CTS wiring run over wooden battens,

4.       Metal sheathed wiring,

5.       Conduit wiring. VIR wires run in metallic or plastic conduits.

Conduit type is considered to be the best wiring system. Metal conduit provides better protection and safety. However, whether metallic or non-metallic, conduit wiring gaining preference as wiring system.


Calculation of electric energy consumption:

                In a house (i) 20 lamps of 100 watts each working 6 hrs./day, (ii) a 1500 w heater working 8 hrs./day and (iii) a 2 HP motor of 85% efficiency works 4 hrs./day. Calculate total no. of units consumed during a month of 30 days. And sum up the total cost for the month (Rs. 5/unit).

                Energy taken by lamp/day= 20 x100 x6 watt/

                Energy taken by heater/day=1500 x8 =

                Energy taken by motor/day= (2x746x4)/

                So, total energy /

                Hence the units consumed during the month= (31021×30)/1000=930.63 k.w.h.

                Total cost for the month=930.63×5=Rs. 4653.15


Safety precautions while using electrical appliances:

                There is no gain saying that electrical appliance and switches all need careful handling. Slightest carelessness can result in nasty shock and burn injuries which may even lead to fatal accident or instant death.

                Electrical accidents normally may be of three types-

  1. fire,

  2. burns,

  3. Shocks.

Fire Danger:

                Electrical short circuits can cause fire. The wiring need to be oveserved and tested from time to time for leakage and short circuits. Electrical sparks may also be another cause of occurring fire. So, faulty wiring must be replaced as and when necessary.

                Fuse of correct rating to be used. Amperage of electric appliances to be noted and proper fuses fixed in circuit.

                Electric heaters are always to be used with guard over heater bars.

                Inflammable materials to be kept at safe place to avoid probable electric spark nearby.


                When burns caused due to electrical fire, first aid is of immediate necessity.


                Short circuit or leakage of electric in appliances or naked wires may be responsible for it. Apart from being fatal, painful shocks may be felt at lower voltage, even down to 25 volts.

                For rescue from shocks expert treatment is very necessary.

Some safety hints:

·         Switch off before touching appliances for any purpose.

·         Replace frayed flex and not to put these under carpet of floors.

·         Avoid sharp bends or kink, in the flexible wires.

·         Avoid joining extra flex with insulating tape.

·         Never to touch switch with wet hands.

·         Beware of bare or un-insulated electric conductors.

·         Before switching on current to nay appliance better make sure that it is properly earthed and wire insulation in good condition.

·         Always switch off the circuits before any repair works undertaken.

·         Connect live wire through switch only.

·         Earthening system to be in good condition.

·         If there is fire, immediately to disconnect supply system.

·         At the time of doing any minor repair work even, switching off the circuit to be done and the jobs done with proper insulated tools and instruments.


Lamp Types:

1.       Carbon filament: consists of carbon filament in evacuated glass bulb. Life about 800hrs.

2.       Metal filaments: here tungsten is used as filament. Life about 850 hrs.

3.       Gas filled coil filament: inert gas such as nitrogen, argon etc. put inside the bulb and coil filament incorporated. Light much whiter than vacuum bulbs.

4.       Mercury or sodium vapour: these are mainly used for street lighting. The colour of light depends on gas used.

5.       Neon-tube lights: used for sign boards and advertisement purpose.

6.       Fluorescent tubes: this is similar to mercury vapour type with a coating of fluorescent material on the inside of the tube. 40 watt power, in effect like 100 watt of metal filament lamp. Gives glare less shadows, cool light. Useful for all general lighting. Life about 2000 hrs.

7.       Incandescent lamps: here light produced by passing electric current through tungsten filament inside the bulb and light comes from the glowing white hot filament.

                Device to be properly selected for efficient and purposeful indoor and outdoor lighting maintaining lower light level for energy conservation.


Electric lighting:

                In lighting system the heights are to be located to get uniform illumination. Both direct and indirect lighting can be used, but then the indirect type is preferable. In this the light rays are reflected from ceilings and walls, thus does not strike the eyes of the people around directly.

                Illumination: one foot candle unit is the illumination produced by one candle at a distance of one foot.

                Lumen: one lumen means one foot candle on one square foot area.

                Consumption of lamps given in watts and the efficiency by the amount of lumens produced per watts consumed.


External Lighting:

                Good internal light create good atmosphere and mood, thus making hotel inside quite comfortable and congenital for use and even food also more appetizing rather.

                External lighting should be such that the hotel stands out significantly from the surrounding lighted areas. It should make the hotel sign clearly visible from a distance. The hotel entrance to be illuminated at a level higher than street lights as far as practicable, having proper brightness. For external lighting mercury vapour lamps on aluminium poles could be gainfully arranged. To use outdoor (external) lights only when needed. For this they may be put on a photocell unit that will turn them off automatically during daylight hours.