57 
 
CHAPTER 04 
ESTABLISHMENTS OF ASSUMPTIONS 
Based on similarity to the three star class hotel operations four hotels (Hotel A, B, C, 
D, E and F) were selected to collect the data and information. Aim of this chapter is 
to identify the average total energy consumption per room per day and hourly energy 
consumption rate on three star hotels. Further to that identify the percentage of 
energy consumption for the air conditioning and laundry & kitchen area from the 
total energy consumption per room per day. 
 
4.1 Introduction 
Information and data was collected from several hotels in relation to the monthly 
total power consumption, annual occupancy and number of guest rooms. All of these 
hotels operation are similar to the three star class hotel operations. Since the 
collected and observed information and data are more relevant and reality to propose 
cogeneration system for a three star hotel.  
 
4.2 Information and Analysis 
Information and data was collected from all four hotels that were mentioned above. 
Most difficulties arise because of unsatisfactory records keeping, technical faults 
such as unavailability’s of measuring instruments in the system and poor attention of 
air conditioning and hot water systems. However was able to collect information 
from employees of the maintenance and accounts department of the hotels.  
 
However none of the hotels has not data about the hourly total power consumption 
and daily consumption of hot water but from the experts ideas that are the 60% of 
the total power requirement per day are on 5:30 AM to 6:30 PM, 20% of that are on 
6:30 PM to 10:30 PM & 10:30 PM to 5:30 AM each and  40% of steam out of total 
amount of generated steam per day have been consumed to generate 50
o
C to 55
o
C of 
hot water for daily consumption. These values are further to confirm the data from 
the proposed applying cogeneration system hotel and also take the electricity 
consumption for air conditioning 1 kW per Refrigerant Ton (RT).   
58 
 
So the collected data with regarding to the power consumption and occupancy rate 
are considered for analysis for individual hotel basis. 
 
4.3 The Hotel – “A” Data Analysis 
This hotel locates the border of southern province at Galle district. This hotel type is 
four- star hotel consisting of 133 guest rooms, one number of conference hall and 
two restaurants. Facilities are catered across the 439 m
2
 including the swimming 
pool, gym, lounge bar and aryurvedic health center. 
Electricity energy source is CEB and air conditioning supplied by the four number 
of water cool chillers. Out of that one unit 200RT capacity screw- chiller, two units 
90 RT & one unit 50 RT capacity reciprocating chillers). Hot water generation 
method was diesel fuel steam boilers. All guest rooms’ air conditioning system 
supplied by the chilled water fan coil units (FCU) and facilities & common areas for 
that by the air handling units (AHU).  
 
4.3.1 The Hotel – “A” data 
Data collected from this hotel is monthly power consumption and annual occupancy 
range, which are as follows. Monthly electricity energy consumption (kWh) and 
monthly maximum demand (kVA)   
Table 4.1: Monthly power consumption of The Hotel- A 
 
 
 
 
 
 
 
 
 
 
 
 
Month 
Power Consumption 
kWh KVA 
January 175730 486 
February 162640 534 
March 192020 506 
April 196620 564 
May 190540 565 
June 207210 520 
July 203590 562 
August 216460 585 
September 214540 572 
October 202730 565 
November 182810 565 
December 181590 605 
59 
 
Annual occupancy rate  
            Table 4.2: Annual occupancy range of The Hotel- A 
Months 
Rate % 
0-25 26 - 50 51 - 75 75 - 100 
January to March       X 
April to June     X   
July to September       X 
October to December       X 
 
4.3.2 The Hotel “A” – data analysis 
According to the mentioned above data, analysis of the power consumption details 
per room per day are as Table 4.3. 
 
       Table 4.3: Power consumption details per room per day of The Hotel- A 
Month Power Consumption 
Power consumption 
/room 
kWh KVA kWh/day kVA 
January 175730 486 44 4 
February 162640 534 41 4 
March 192020 506 48 4 
April 196620 564 49 4 
May 190540 565 48 4 
June 207210 520 52 4 
July 203590 562 51 4 
August 216460 585 54 4 
September 214540 572 54 4 
October 202730 565 51 4 
November 182810 565 46 4 
December 181590 605 46 5 
 
To get the average power consumption per day per room, have to consider the all 
months. According to that annual consumption will get the average kWh per room 
per day because of the seasonal changes is occurred in some months. 
Total power consumption for year  2,326,480 kWh 
Average kWh per room, day   ( ( 2,326,480 ) / (133 X 360)) 
      49 kWh 
60 
 
Annual occupancy rates are 9 months occupied 75% to 100 % and 3 months 
occupied 50% to 75%. Analysis of the power consumption this seasonal occupancy 
has to be considered. For calculation purposes get the average value from the 
occupied range. Means of that average of 65 % occupancy for 3 months & 85 % 
occupancy for 9 months 
 
Corrected value   ((49 / 0.65) X 0.25) + ((49 / 0.85) X 0.75) 
     62 kWh 
When considering the maximum kVA demand, have to consider the all year because 
all seasonal trends are covering during the year.  
According to that table maximum kVA demand recorded on the month of 
December, that month average occupancy is about 90%. 
Maximum kVA demand during the year 605 kVA 
Maximum kVA demand per month, room (605 / 133) 
       4.55 kVA 
Corrected value    (4.55 / 0.9) kVA 
       5.05 kVA 
4.4 The Hotel “B” Data Analysis 
This hotel locates the southern province at Galle district. This hotel type is tourist 
resort (smell luxury hotel) consisting of 63 guest rooms, two number of conference 
hall and two restaurants. Facilities are catered across the 1571 m
2
 including the 
swimming pool, gym, club bar and spa. 
 
Electricity energy source is CEB and air conditioning supplied by the one number of 
160 RT capacity reciprocating water cool chillers. Hot water generation method was 
diesel fuel steam boilers. All guest rooms’ air conditioning system supplied by the 
chilled water fan coil units (FCU) and facilities & common areas for that by the air 
handling units (AHU).  
 
 
 
61 
 
4.4.1 The Hotel “B” - data 
Data collected from this hotel is monthly power consumption and annual occupancy 
range, which are as table 4.4. 
Monthly electricity energy consumption (kWh) and monthly maximum demand 
(kVA)  
Table 4.4: Monthly power consumption of the Hotel B 
  Power Consumption 
Month kWh kVA 
January 37,967 206 
February 65,520 252 
March 65,214 239 
April 76,210 213 
May 84,548 256 
June 91,795 305 
July 92,250 262 
August 96,843 250 
September 104,564 282 
October 94,151 255 
November 95,017 267 
December 91,976 269 
 
Annual occupancy rate 
 
                Table 4.5: Annual occupancy range of the Hotel- B 
Months 
Rate % 
0 - 25 25 - 50 50 - 75 75 - 100 
January to March       X 
April to June     X   
July to September      X 
 
October to December       X 
 
 
4.4.2 The Hotel “B” – data analysis 
According to the mentioned above data, analysis of the power consumption details 
per room per day are as table 4.6. 
 
62 
 
Table 4.6: Power consumption details per room per day of the Hotel B 
Month Power Consumption 
Power Consumption / 
room 
kWh kVA kWh / day kVA 
January 37,967 206 20 3 
February 65,520 252 35 4 
March 65,214 239 35 4 
April 76,210 213 40 3 
May 84,548 256 45 4 
June 91,795 305 49 5 
July 92,250 262 49 4 
August 96,843 250 51 4 
September 104,564 282 55 4 
October 94,151 255 50 4 
November 95,017 267 50 4 
December 91,976 269 49 4 
 
To get the average power consumption per day per room, have to consider the all 
months. According to that annual consumption will get the average kWh per room 
per day because of the seasonal changes is occurred in some months. 
 
Total power consumption for year  996,055 kWh 
Average kWh per room, day   ( ( 996,055 ) / (63 X 360)) 
      44 kWh 
 
Annual occupancy rates are 6 months occupied 75% to 100 % and other 6 months 
occupied 50% to 75%. Analysis of the power consumption this seasonal occupancy 
has to be considered. For calculation purposes get the average value from the 
occupied range. Means of that average of 65 % occupancy for 6 months & 85 % 
occupancy for 6 months 
 
Corrected value    ((44 / 0.65) X 0.5) + ((44 / 0.85) X 0.5) 
      59.72 kWh 
When considering the maximum kVA demand, have to consider the all year because 
all seasonal trends are covering during the year.  
63 
 
According to that table maximum kVA demand recorded on the month of June, that 
month average occupancy is about 95%. 
 
Maximum kVA demand during the year 605 kVA 
Maximum kVA demand per month, room (605 / 63) 
      4.84 kVA 
Corrected value    (4.84 / 0.95) kVA 
      5.1 kVA 
 
4.5 The Hotel “C” Data Analysis 
This hotel locates the western province at Gampaha district, Negombo lagoon area. 
This hotel type is star class beach resort consisting of 126 guest rooms, two number 
of conference hall and two restaurants. Facilities are swimming pool, gym, 
discotheque and games & animation area. 
 
Electricity energy source is CEB and air conditioning supplied by the three number 
of 50 RT capacity reciprocating water cool chillers for the guest room areas and for 
the conference, restaurant and office areas supplied by the separate water cool 
package units. Hot water generation method was diesel fuel steam boilers. All guest 
rooms’ air conditioning system supplied by the chilled water fan coil units (FCU).  
 
4.5.1 The Hotel –“C” - data 
Data collected from this hotel is monthly power consumption and annual occupancy 
range, which are as follows. 
Monthly electricity energy consumption (kWh) and monthly maximum demand 
(kVA)  
 
 
 
 
 
 
 
64 
 
Table 4.7: Monthly power consumption of the Hotel C 
Month 
Power Consumption 
kWh KVA 
January 94,899 275 
February 128,617 279 
March 105,122 288 
April 133,457 296 
May 107,811 292 
June 141,096 282 
July 147,076 299 
August 125,262 298 
September 99,841 256 
October 97,530 255 
November 118,862 286 
December 118,101 264 
 
Annual occupancy rate are 50% occupied in 7 months 65% occupied in 5 months. 
Following table depicts the average occupancy data. 
              
   Table 4.8: Annual occupancy range of the Hotel C 
Months 
Rate % 
0 - 25 25 - 50 50 - 75 75 - 100 
January to March      X 
 
April to June    X 
 
  
July to September    X  X 
 
October to December     X  
 
 
 
4.5.2 The Hotel “C” – data analysis 
According to the mentioned above data, analysis of the power consumption details 
per room per day are as table 4.9. 
 
 
 
 
 
65 
 
       Table 4.9: Power consumption details per room per day of the Hotel C 
Month Power Consumption 
Power Consumption / 
room 
kWh KVA kWh/day kVA 
January 94,899 275 25 2 
February 128,617 279 34 2 
March 105,122 288 28 2 
April 133,457 296 35 2 
May 107,811 292 29 2 
June 141,096 282 37 2 
July 147,076 299 39 2 
August 125,262 298 33 2 
September 99,841 256 26 2 
October 97,530 255 26 2 
November 118,862 286 31 2 
December 118,101 264 31 2 
 
To get the average power consumption per day per room, have to consider the all 
months. According to that annual consumption will get the average kWh per room 
per day because of the seasonal changes is occurred in some months. 
Total power consumption for year  1,417,674 kWh 
Average kWh per room, day   ( ( 1,417,674 ) / (126 X 360)) 
      31.25 kWh 
As mentioned above annual occupancy rates are 7 months occupied 50% and other 5 
months occupied 65%. Analysis of the power consumption this seasonal occupancy 
has to be considered.  
Corrected value   ((31.25 /0.5) X 0.58) + ((31.25 / 0.65) X0.42) 
     56.44 kWh 
When considering the maximum kVA demand, have to consider the all year because 
all seasonal trends are covering during the year. According to that table maximum 
kVA demand recorded on the month of July, that month average occupancy is about 
55%. 
Maximum kVA demand during the year 299 kVA 
Maximum kVA demand per month, room (299 / 126) kVA = 2.37 kVA 
Corrected value    (2.37 / 0.55) kVA  = 4.31 kVA 
66 
 
4.6 The Hotel “D” - Data Analysis 
This hotel locates the southern province at Galle district in Hikkaduwa area. This 
hotel is resort type three star class hotel consisting of 154 guest rooms, one number 
of conference restaurant. Facilities are swimming pool, gym with sauna. 
Electricity energy source is CEB and air conditioning supplied by the two number of 
120 RT capacity reciprocating water cool chillers. Hot water generation method was 
diesel fuel steam boilers. All guest rooms’ air conditioning system supplied by the 
chilled water fan coil units (FCU) and facilities & common areas for that by the air 
handling units (AHU). 
 
4.6.1 The Hotel “D” – data 
Data collected from this hotel is monthly power consumption and annual occupancy 
range. However the maximum kVA demand for each month unable to observed 
from the data books.  
 
Monthly electricity energy consumption (kWh) and monthly maximum demand 
(kVA) 
Table 4.10: Monthly power consumption of the Hotel D 
Month Power Consumption 
January 157,692 
February 137,624 
March 151,211 
April 154,544 
May 132,739 
June 114,454 
July 134,574 
August 164,126 
September 129,917 
October 147,843 
November 136,667 
December 192,075 
 
Annual occupancy rate are 60% occupied in 6 months 40% occupied in rest of the   
6 months. Following table depicts the average occupancy data. 
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                Table 4.11: Annual occupancy range of the Hotel D  
Months 
Rate % 
0 - 25 25 - 50 50 - 75 75 - 100 
January to March      X 
 
April to June    X 
 
  
July to September    X   
 
October to December     X  
 
 
4.6.2 The Hotel “D” – data analysis 
According to the mentioned above data, analysis of the power consumption details 
per room per day are as follows. 
 
       Table 4.12: Power consumption details per room per day of the Hotel D 
Month Power 
Consumption kWh 
Power consumption 
kWh/room per day 
January 157,692 34 
February 137,624 30 
March 151,211 33 
April 154,544 33 
May 132,739 29 
June 114,454 25 
July 134,574 29 
August 164,126 36 
September 129,917 28 
October 147,843 32 
November 136,667 30 
December 192,075 42 
 
To get the average power consumption per day per room, have to consider the all 
months. According to that annual consumption will get the average kWh per room 
per day because of the seasonal changes is occurred in some months. 
 
Total power consumption for year  1,753,466 kWh 
Average kWh per room, day   ( ( 1,753,466 ) / (154 X 360)) 
      31.63 kWh 
68 
 
As mentioned above annual occupancy rates are 6 months occupied 60% and other 6 
months occupied 40%. Analysis of the power consumption this seasonal occupancy 
has to be considered.  
Corrected value   ((31.63 /0.5) X 0.6) + ((31.63 / 0.5) X0.4) 
     62 kWh 
 
4.7 Summary and Conclusion 
Based on above hotels corrected values for the energy consumption per room per 
day and maximum kVA demand per room will establish the average values of that 
as follows.  
 
Corrected kWh value per room per day for The Hotel “A”  62 kWh 
Corrected kWh value per room per day for The Hotel “B”   60 kWh 
Corrected kWh value per room per day for The Hotel “C”  56.44 kWh 
Corrected kWh value per room per day for The Hotel “D”  62 kWh 
 
Average kWh value per room per day  ((62 + 60 + 56.44 + 62) / 4) 
kWh 
       60.11 kWh 
Assume      60 kWh 
 
Corrected kVA value per room for The Hotel “A” 5.05 kVA 
Corrected kVA value per room for The Hotel “B” 5.1 kVA 
Corrected kVA value per room for The Hotel “C” 4.31 kVA 
 
Average kVA value per room per month  ((5.05 + 5.10 + 4.31) / 3) kVA 
       4.82 kVA 
Assume      5 kVA 
Further to above information, collect following informations from the experts of the 
hotel sector industries. 
   
69 
 
1. Daily electricity consumption for air conditioning is 50 % of the total 
electricity requirement. Electricity power requirement for 1 RT is 1 kW. 
2. Daily electricity demand as follows, 
 5:30AM to 6:30PM - 60% of the daily demand 
 6:30PM to 10:30PM - 20% of the daily demand. 
 10:30PM to 5:30AM  - 20% of the daily demand. 
3. Daily electricity consumption for kitchen & laundry is 10% of the electricity 
consumptions. Subsequent of that 6 kWh / day per room.