energy wise hotels

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Energy Wise HotelsTOOLKIT DECEMBER 2007


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City of Melbourne, December 2007

PO Box 1603, Melbourne, Victoria 3001

Hotline 61 3 9658 9658

TTY 61 3 9658 9461

Email [email protected]

Web www.melbourne.vic.gov.au

This is a publication of the Melbourne City Council.

The Energy Wise Hotel Toolkit is printed on Monza Satin Recycled. Monza has a high 55%

recycled fibre content, including 30% pre-consumer and 25% post-consumer waste and FSC

certified pulp. Monza Recycled is sourced from sustainable plantation wood and is Elemental

Chlorine Free (ECF).

Disclaimer statement

The content that appears in this publication is provided for information purposes only. No claim

is made as to the accuracy or authenticity of the content. Sustainability Victoria does not accept

any liability to any person for the information or advice (or the use of such information or advice)

which is provided in this publication or incorporated into it by reference.

The information in the Sustainability Victoria publication is provided on the basis that all persons usingthe publication undertake responsibility for assessing the relevance and accuracy of its content.

Sustainability Victoria does not accept any liability for loss or damages incurred as a result

of reliance placed upon the content of this publication.

2 Energy Wise Hotel TOOLKIT


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Introduction

The hotel industry is one of the fastest growing industries in the world due to

increased tourism and market globalisation.

At the same time hotels are providing more facilities and services to customers,

leading to increased energy consumption.

As the cost of energy in Australia is increasing, and its use is shown to accelerate

climate change, the hotel industry is becoming more aware of the impact of their

business on the environment. Today most guests are aware of climate change due

to the generation and consumption of energy.

The Energy Wise Hotels Toolkit has been developed to assist accommodation service

providers to reduce their energy consumption. The toolkit also outlines energy

consumption patterns in hotels and the impact this has on our environment.

This toolkit provides comprehensive recommendations on energy reduction

opportunities with technical explanations. Hotel management can use the toolkitto develop the action plans necessary to improve the energy efficiency of the hotel,

without sacrificing the comfort of guests. This not only makes the hotel business

more profitable but presents a favourable image of hotels that can be marketed.

Who is this Toolkit for?

The Energy Wise Hotels Toolkit has been developed for:

hotel management;

engineers; and

staff members responsible for training and work practices.

The toolkit is divided into chapters to enable hotel operators to apply relevant

information to their own hotel. Each chapter may not be relevant for every hotel,depending on the structure and utilities at each hotel.

The toolkit is based on information obtained from a series of 10 energy audits

undertaken as part of the City of Melbournes Savings in the City Green Hotels

program. Case studies carried out by Energy Efficiency Opportunities Australia

(EEO) are also sourced throughout the toolkit, as well as information collected

from general surveys and consultancies in energy conservation.

The Energy Wise Hotels Toolkit

03Energy Wise Hotel TOOLKIT


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Using this Toolkit

This toolkit comprises nine sections:

Section 1: Why be energy efficient?

Outlines benefits of conserving energy

Section 2: Energy use and performance indicators

Identifies which areas in hotels are generally the largest energy consumers

Section 3: Energy monitoring and tracking

Deals with the key parameters to be monitored and tracked in order to improve

energy efficiency

Section 4: Taking action

Explains how to start implementing energy saving ideas in your hotel

Section 5: Understanding energy

Basic explanation of energy

Section 6: Energy saving initiatives

Outlines possible energy saving opportunities for hotels

Section 7: Involving staff and guests

Outline of engagement and training techniques for staff and guests

Section 8: Renewable energy

Explains the role and value of sourcing energy from renewable sources such

as wind, power and solar power

Section 9: Technology discussion

Includes three fact sheets with more detailed information and tips to aid energy

conservation in your establishment. These include:

lighting;

heating, ventilation and air conditioning;

variable speed drives; and

environmental management systems.



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The Energy Wise Hotels Toolkit

05

Acknowledgements

We would like to thank the following organisations for their help and information:

Enman Pty Ltdwww.enman.com.au

EEO, Department of Industry, Tourism and Resources

www.energyefficiencyopportunities.gov.au

Crowne Plaza, Melbournewww.crowneplaza.com.au

Grand Hyatt, Melbournewww.grandhyatt.com.au

Hotel Ibis, Melbournewww.hotelibis.com.au

Jasper Hotelwww.jasperhotel.com.au

Saville City Suites, East Melbournewww.savillehotelgroup.com

Saville on Russell, Melbournewww.savillehotelgroup.com

Melbourne Marriottwww.marriott.com.au

Sofitel Grand Hotel, Melbournewww.sofitel.com.au

Sebel Melbournewww.mirvachotels.com.au

Hilton on the Park, Melbournewww.hiltonhotels.com.au

This Energy Wise Hotels Toolkit was researched and produced by Enman Pty Ltd.

Energy Wise Hotel TOOLKIT


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Why save energy?

Energy is fundamental for maintaining comfort standards in a hotel however

it is important this energy is used efficiently. Like water and waste efficiencies,

the benefits of being energy efficient are:

reducing your hotels environmental impact;

cost saving on energy bills; and

enhancing your hotels reputation for protecting the environment.

Energy is the largest generator of human-induced greenhouse gas emissions.

Greenhouse gases cause global warming which is detrimental to our natural

environment systems.

Some of the effects of global warming are:

a rise in sea level causing coastal damage;

an increase in the likelihood of extreme weather conditions such

as droughts, floods and cyclones;

health impacts because of the spread of tropical-borne diseases,the increase of flooding and other such climate changes;

damage to ecosystems and species diversity;

damage to agricultural output and food supply; and

an increase in the earths surface temperature causing heatstress and damage.

Reducing the energy consumption in hotels helps reduce greenhouse gas emissions.

Refer to Appendix B for details about the environmental impact due to energy

generation and use.

Why be energy efficient? 1



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Energy use and performance indicators 2

09

Before energy use can be reduced in a hotel, motel, servicedapartment or hostel, it is necessary to understand where energyis being consumed. It is also helpful to compare your hotels

energy consumption to other similar hotels.

2.1 Energy balance

An energy balance shows where and how much energy is being used in the hotel.

The two most common sources of energy consumed in hotels are:

electricity; and

thermal energy this is usually natural gas, however in remote places LPGand other forms of fuel are used.

Typical energy consumption in hotels is spread relatively evenly to a number of uses

including kitchens, heating, cooling and lighting. This is shown in Figure 2.1 below.

Figure 2.1: Example of total energy consumed in a hotel

Most of these uses are serviced by electricity (See Figure 2.2), with gas primarily

used for hot water and heating (see Figure 2.3).

Figure 2.2: Typical electricity consumption


10% AHU, FCU and ventilation fan

10% Laundry

10% Lighting

3% Refrigeration

13% Space heating

14% Domestic & pool water heating

15% Chiller

1% Miscellaneous

7% Pump

7% Kitchen

10% Electric heating

17.6% AHU, FCU and ventilation fan

17.2% Electric heating

26.6% Chiller

5.6% Refrigeration

12.0% Pump

18.7% Lighting

2.3% Miscellaneous


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Figure 2.3: Typical thermal (gas) consumption

2.2 How much energy can you save?

It is very important to know how energy efficient your hotel is and where potential

savings could be made through energy conservation.

Performance indicators and benchmarking

Benchmarking your initial energy use is a convenient way to compare the energy

efficiency of hotels. It is important for the benchmark to consider the star quality

rating of a hotel so that the comparison is meaningful. Benchmarks are also

known as an energy index or as performance indicators.

Energy performance benchmarking is an internal management tool designed

to provide ongoing, reliable and verifiable tracking of the hotels performance.

Realistic targets can then be set for improving efficiency by hotel management.

The most useful performance indicators of hotels are:

gigajoules (GJ) per square metre of floor area; and

GJ per guest.

Table 2.1 shows energy benchmarks that are used by hotels in Australia.

Table 2.1: Benchmarks for energy consumption per square metre (GJ/m2.year) for a hotel

Note: Benchmark figures are based on surveys conducted on hotels in various regions,

and buildings of similar nature by Benchmark Hotel, EEO (Energy Efficiency Office)

and IHG Hotels operating results.


16% kitchen

32% domestic & pool water heating

30% Space heating

22% Laundry

Rating Energy use

(GJ/m2.year)

Very Good < 0.95

Good 0.95 - 1.09

Satisfactory 1.09 - 1.24

Poor 1.24 - 1.38

Very Poor > 1.38


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To achieve energy savings it is important to monitor and track energy consumption,and generate reports on a regular basis. Such a system forms the basis of any ongoingand sustainable energy management program.

There are standard software packages available to monitor and track energy and greenhouse gas emissions.

However, hotels and hotel groups can easily create their own simple database. Some of the key features

required for tracking energy efficiency are:

comparison of energy consumption and key performance indicators;

bar graphs of energy use and performance index for 12 months over the pastfew years as shown in Figure 3.1 and Figure 3.2; and

comparison of actual energy use against target consumption (Figure 3.3).The target can be generated according to seasonally adjusted monthly energy use.

Figure 3.1: Bar graph of electricity consumption over three years

Energy monitoring and tracking 3


0

20

40

60

80

100

120

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

2004 2005 2006

ElectricityConsumptions(MWh/year)



Figure 3.2: Bar graph of natural gas consumption over three years

Figure 3.3: Actual electricity consumption versus target consumption

0

20

40

60

80

100

120


2004 2005 2006

GasConsumptions(G

J/year)

0

20

40

60

80

100

120


Actual Target

ElectricityC

onsumptions(MWh/year)


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Taking Action 4


In order to implement successful energy saving you must have a well structured and realisticplan with management support.

4.1 Following an energy management frameworkAdopting a sustainable energy management framework is the first step of any energy and greenhouse gas emission

reduction program. When developing an energy management plan it is recommended you consider the steps shown

in the following flow chart:

Figure 4.1: Energy management plan represented in a flow chart

The following sections outline each stage of the framework in more detail.

4.1.1 Corporate energy policy

A corporate energy policy sets the directive and basis on which the energy management plan is developed.

This policy must be approved by senior management and endorsed by the CEO. The policy is then circulated

to all staff to ensure a common understanding by staff at all levels.

The corporate energy policy should link to other environmental policies, primarily waste and water management.

An example of a corporate energy policy is shown at Appendix A.

Adopt a Corporate energy policy

Develop an

energy management plan

Adopt a Energy

management coordinator

Identify and train energy champions

Non-capital intensive

Energy Management Initiative

Capital intensive

Energy Management Initiative



4.1.2 Developing an energy management plan

The energy management plan is the plan of action to improve the energy efficiency of a hotel by setting out clear

objectives and targets. To achieve these objectives, management needs to assign responsibilities and allocate resources.

4.1.3 Energy management coordinators

An energy management coordinator is required for all accommodation establishments; one per hotel or one per

group of hotels of the same chain. Their responsibility is to manage and coordinate all energy management functions

in the hotel.The coordinator needs to monitor and report energy consumption and performance as well as drive all of the planned

energy management initiatives (EMIs) of the hotel. The coordinator must be fully trained and motivated to carry out

the required tasks efficiently and effectively.

4.1.4 Energy champions

Energy champions are staff members who can assist with the day-to-day energy management action plan.

Hotel service engineers and other supervising staff are the ideal people to be designated as energy champions.

Energy champions should be properly trained along with the energy coordinator to achieve satisfactory outcomes

for the hotel. This is a great professional development opportunity for motivated staff.

4.1.5 Introduce energy awareness program

Introducing an energy awareness program consists of several components which are discussed in detail

later in this toolkit. These are:

education program;

display of corporate commitment in staff member common areas; and

promotion of energy management through various means including stickers.

Figure 4.2: An example of energy sticker


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Understanding energy 5


It is important to understand the basics of energy to monitor and control it.

A guide to understanding energy units

What does the term power mean?

The term power refers to the rate of change of energy. It is a way of describing the capacity needed

to make appliances or equipment operate effectively.

For example:

A lamp of 100 wattage: Power is 100 wattage

A heater rated 1 kilowatt (KW): Power is 1 kW (1000 wattage)

What does the term energy mean?

The term energy links power to length of time.

ENERGY = POWER x TIME OF OPERATION

ENERGY = WORK DONE BY A SOURCEUnit of energy = Joule (J) 1 kilowatt hour (kWh) = 1 kilowatt operates for 1 hour 1 kW = 3.6MJ/hr

= 10 lamps operate for 1 hour 1 kWh = 3.6 MJ

= The heater operates for 1 hour

How do energy and power link together?

Most common units:

POWER = kW , joules/sec

ENERGY = kWh , GJ

1 kWh = 3.6 MJ

What are the main types of electric power transmission?

1. Three-phase electricity

Many electric motors employ a three-phase load design which runs three alternating currents of the

same frequency at different times to give constant power in an efficient, compact and longer-lasting way.

Used in pumps, fans, blowers, compressors and some air-conditioning units.

Power (kW) = Volts (line) x Amps (line) x 3 x Pf

Note: The power factor (Pf) of electric motors is designed at around 0.8 to 0.9. The Pf decreases as motor load decreases.

2. Single-phase electricity

Employs a single circuit of electricity current.

kW = Volts x Amps x Pf

Example 1:1 kW motor (full load) operates for 16 hrs/day, 300 days/year

Power = 1 kW

Energy = 1 x 16 hrs/day x 300 days /year

= 4,800 kWh/year

1 Btu = 1.05506 kJ or 2519 kcal

1 calorie = 4.187 joules



5.1 Greenhouse gas emission factors

Once the amount of power and energy used for operations is understood, it can then be converted into

greenhouse gas emissions.

Factors used to calculate the greenhouse gas emissions associated with consumption of different fuels

and activities are provided below:

Electricity greenhouse gas emission factor: 1.325 kg CO2-e/kWh

Natural gas greenhouse gas emission factor (Small user


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Energy saving initiative 6


Energy savings equal financial savings. Hotels can deliver a rangeof energy saving initiatives grouped as either:

Initiatives that require little or no capital.

These are the energy management initiatives to consider first in your energy

management plan as they require little or no finance and are simple to do.

Initiatives that require capital investment.

These should be considered based on individual merit.

These opportunities are outlined in more detail in the following sections.

6.1 Energy management initiatives the first steps

Simple energy management initiatives that require little or no financing include:

changing operations and practices around the hotel;

purchasing energy efficient equipment;

energy efficient maintenance; and

introducing an energy awareness program for staff and guests.

6.1.1 Change of operational practice

By simply altering the operations of your accommodation facility you can save

a large amount of energy with little cost.

Some of the simplest ways to conserve energy are:

Lights

Turn off lights when not required. Lights in common areas are under staffcontrol; therefore staff should turn off lights in common areas when not in use.This can be achieved by conducting a staff awareness program.

Dim reception and foyer lights from late night to early morning when thereis minimal activity. This can be achieved whilst still maintaining guest safetyand comfort.

Lights in guest rooms are under guest control. Encourage guests to turn off lightsthrough energy and climate change promotional stickers. Invite guests to join theefforts of the hotel to reduce greenhouse gas emissions and inform them of someof the hotels initiatives. This will encourage guests to reduce their own energy use.

Air conditioning

Similar to lighting, the air conditioning can be turned off when its useis not necessary.

Increasing the room temperature during cooling provides energy savingsof around five to 10 per cent of the cooling load.

It is recommended the cooling temperature is set to 24C.



Heating

Decreasing the room temperature during the cooler months can lower theheating load by five to 10 per cent. It is recommended the heating temperatureis set at 18C.

Kitchen

Turn off the exhaust fans in the kitchen when not required.

Reduce the speed of fans during times of low kitchen activity by using a variable

speed drive. Installing a variable speed drive is a wise financial investment,as the reductions in energy bills quickly repay the initial investment.

Hot water

Set hot water temperature to as low as possible. The recommended hot watertemperature is around 60C.

Office equipment

Turn off office equipment such as computers, computer screens and printers whennot in use, especially after hours. Explain the benefits to staff so they participate inreducing the energy needs from office equipment.

Always enable energy star features on office equipment to give it the ability topower down or sleep when they are not being used and wake up when they areneeded. For more information refer to the Australian Department of EnvironmentGreen Office Guide 2001.

6.1.2 Buying energy efficient equipment

Incorporate the purchase of energy efficient equipment into the energy

management program.

Typically energy efficient equipment is more expensive than the standard option;

however the energy savings achieved usually provide adequate paybacks.

In addition, equipment needs to be replaced periodically anyway so this is

often a perfect opportunity to invest in energy efficient equipment.

Some examples of energy efficient equipment are:

Office equipment typically any equipment with a star rating showing is a highlyenergy efficient product.

A flat screen monitor uses less energy than a traditional CRT monitor; and laptops

consume less energy than desktops.

The hard drive of an average computer uses 49 watts when fully turned on, 29 watts

when asleep and two watts when switched off.

The average monitor uses 60 watts when in use, 6.5 watts when in sleep mode and

one watt when switched off.

Make sure energy saving modes are installed on computers and are operational.

Use recycled paper which requires 90 per cent less water and 50 per cent

less energy to produce and whenever possible print on both sides of the page.Buy other recycled or reused products wherever possible such as furniture.Lease photocopiers where possible.

Laundry services buy washing machines and dryers with higher energy starratings that show energy efficiency performance. Be sure to consider waterefficiency when making these purchases.


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Motors and chillers purchase higher energy efficiency equipment. It is worthpaying more for an energy efficient motor (likely to be an increased cost of around10 to 20 per cent) with an efficiency of between two and four per cent. Over thelikely 20-year life of the equipment, the capital outlay is small compared to thecost of running it as shown in Figure 6.1 below.

Figure 6.1: Life Cycle Costs of a 55 kW Motor

Assumption: 20-year service life with an electricity price of 10/kWh.

Lighting buy compact fluorescent lamps instead of incandescent, this canachieve energy saving of around 75 per cent.

Refrigeration the energy efficiency of refrigerators varies by 50 per cent evenif they meet new stringent minimum energy performance standards (MEPS)introduced in 2005. When purchasing a new refrigerator consider high energystar ratings over cheaper, low star refrigerators as these models will offergreater cost savings.

6.1.3 Energy efficient maintenance

The present trend in the accommodation industry is to cut down maintenance costs

allowing just enough to keep everything running smoothly. However, extending the

maintenance from preventative or breakdown maintenance to energy efficient

maintenance proves to be cheaper in the long-term.

Energy efficient maintenance reduces energy costs and extends the life of equipment.

Some of these maintenance procedures are:

Air handling units

Air handling units condition the air and recirculate it to areas for cooling, heating and

ventilation. Maintenance procedures include:

Replacement of filters in air handling units and fan coil units. The filters can becleaned or replaced about twice a year. This improves energy efficiency as wellas room air quality.

Regular calibration check of thermostat control for the air conditioning system.

Cleaning the motor casings.

Belt drive A V-belt is one of the most common types of power transmission

to fans in air handling units. If the tension of the belt is too high or low or the beltis worn out, the transmission efficiency of the motor is reduced. Transmissionefficiency is dependent on pulley size, torque, under or over belting and V-beltconstruction. Belt tension is also a very important parameter. Under and overbelting can cause an efficiency drop of as high as five per cent.


1.4% Motor cost

98.6% Energy cost



Regular checking of the damper control many of the air handling units foundin hotels have an economy cycle. This allows the fresh air and relief air dampersto open or close depending on ambient weather conditions. The economy cyclecan reduce the cooling load by up to 30 per cent. It has been observed previouslyin other hotels that dampers are often faulty or frozen which causes the systemto operate inefficiently.

Cooling towers

New types of cooling towers with condensers are emerging. These are mixed wet

and dry types which are more water and energy efficient. These condensing cooling

towers operate as air-cooled systems in winter and water-cooled systems in summer.

Regular checking of cooling tower performance it is sometimes found that coolingtower capacity reduces due to: unequal water distribution; water not wetting thecooling tower pack; or the spay nozzles not spraying efficiently. As a result, thecooling capacity is reduced along with the energy efficiency of supplied chillers.

Motors

Rewinding motors motors are used for pumps, fans, chillers and a large amountof other equipment. As they fail they are normally rewound. Rewinding a motor ischeaper than purchasing a new motor; however each time a motor is rewound itsenergy efficiency is reduced.

The efficiency of rewound motors drops due to the intense heat applied in thestripping of old windings and from using cheaper, thinner gauge wire. Rewinds are

normally priced at between 60 and 80 per cent of the price of a standard new motor.

On average, the efficiency of a motor decreases by about one per cent each time

the motor is rewound.

Supply voltage when the three-phase voltages are not equal, the motor lossesincrease substantially. This is normally due to unequal distribution of the single-phaseloads, such as lighting. A modest phase imbalance of two per cent can increasemotor losses by 25 per cent or overall motor efficiency by around 1.6 per cent.

When operating at less than 95 per cent of design voltage, motors typically lose

efficiency by two to four per cent. Supply voltage over and under the rated voltage

can also significantly reduce energy efficiency.

6.2 Energy management initiatives capital intensive

Capital intensive initiatives are energy saving projects that require small to large

financing. These projects should be considered based on their individual merits

which include:

payback time how quickly the works pay for themselves in the formof reduced energy bills and maintenance costs;

quantity of saving of financial dollars and greenhouse emissions; and

other associated benefits such as water, waste, health, noise andamenity improvements.


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6.2.1 Energy saving in HVAC systems

Heating, ventilation and air conditioning systems (HVAC) are typically a major energy

user in hotels. HVAC can consume as much as 70 per cent of a hotels total energy

consumption. However, this is also an area where significant improvements can be

made. Energy efficiency improvement of up to 50 per cent is achievable depending

on HVAC configuration control and operation.

The energy saving opportunities in HVAC systems are:

Economy cycle this is one of the most commonly recommended energy saving

functions for HVAC systems. The economics of retrofitting an economy cycle depend

on the following factors:

Capacity of the AHU fan sizes less than 5 kW are less economically viable.

Fresh air supply duct size if the fresh air duct which brings the fresh air to theAHU does not require any modification to bring 100 per cent fresh air it is easyand more economically viable to retrofit an economy cycle.

Control system if there is a building management system (BMS) the facility shoulduse direct digital control (DDC) and enthalpy-based control to provide more energysavings. The anticipated energy saving is around 25 per cent in Melbourne.If there is an economy cycle fitted, then check the operation as follows:

- Is the controller still functional?- Is the controller calibrated correctly?

Economiser an economiser is a heat recovery system. Installing an economiser

is a good way to improve the energy efficiency of a HVAC system. An economiser

is more economically viable when implemented during the installation of the HVAC

system. You should consider an economiser when the AHU system is on 100 per cent

fresh air. Economisers are generally more viable in extreme weather conditions such

as very cold or very hot. Melbournes weather is suitable for the use of economisers.

Variable speed drive (VSD) installing variable speed drives on supply and return

air fans is a new trend in energy management. Implementation as a retrofit is very

simple and economically viable. Conventionally VSD were viable only if the system

was designed as a VAV (variable air volume) system. However, an advanced controlalgorithm allows you to implement a VSD for any type of air conditioning system.

The anticipated energy saving is around 45 per cent of the fan energy depending

on the algorithm used for control and the humidity requirement in the space. As hotel

air conditioning generally functions to provide comfort conditions, humidity is not a

critical parameter.

Infiltration of air reducing the infiltration of ambient air into air conditioned spaces

reduces the air conditioning load. The guest entrance door in the foyer of the hotel

is an area where automatic double doors or revolving doors can be considered.

Room temperature setting room temperature setting is one of most

important criteria for energy conservation through change of operational practice.

It is recommended room temperatures in winter are set as low as possible;

even as low as 18C and during summer as high as 25C.




Chiller system chillers are another large energy consumer in the hotel industry.

Chiller efficiency can be improved by measures outlined below.

Use energy efficient chillers: if chillers are old, replace them with a water-cooledturbo compressor fitted with a VSD. This can improve energy efficiency by upto 400 per cent.

Use a different size or capacity of chiller: a smaller capacity chiller shouldbe used in low load conditions and a larger chiller for high load conditions.Operating a chiller at part-load conditions reduces the efficiency of a

conventional fixed speed chiller.

Electronic expansion valve (for reciprocating compressors): if the expansion valveis electromechanical, replace it with modern electronic valve. This can improveefficiency by around 15 per cent.

Use a chiller with remote set point control facility.

It is common practice to design the cooling tower with minimum capacity.Increasing the cooling tower capacity can increase chiller efficiency.Therefore, provide adequate cooling capacity for cooling tower.

Use a common cooling tower for all chillers with common header and discharge -this not only provides the opportunity to save energy but also provides greaterreliability of the chiller system.

Use variable speed drives for the following areas:

- secondary chilled water pump;

- primary chilled water pump;

- condenser water pump; and

- cooling tower fans VSD for a cooling tower fan not only reduces fanenergy but also can improve energy efficiency of the chiller compressor.

Tune control system to avoid simultaneous heating and cooling.

Insulate ducts and chilled water pipes to prevent heat gain.

Energy efficient comfort condition of HVAC system the comfort level

of air conditioned spaces depends on the following variables:

- gender;

- activity;

- relative humidity and dry bulb temperature; and

- air movement.

Refer to section 9.2.2 for more information on air conditioning comfort

Why cool high?

Adjust your cooling comfort zone to as high as possible. An increase of 1C

in temperature will reduce your energy consumption by five to 10 per cent.

Why heat low?

Adjust your heating comfort zone to as low as possible. A decrease of 1C

in room temperature will reduce your energy consumption by five to 10 per cent.



Glazing and shading glass windows are one of the major contributors to air

conditioning load. Appropriate measures must be taken to ensure hotel windows

are efficient. Some energy saving measures that can be implemented are:

window glazing a double-glazed window will not only reduce the coolingand heating load of the building but also reduces noise levels in the building;

use of energy efficient glass that allows less heat to transfer through the glass;

use of tinted glass to reduce solar absorption this not only reduces energy

consumption but also improves comfort conditions in the hotel. It is especiallyeffective for windows facing north and west.

Building insulation building insulation also helps reduce the heating and cooling

load of a hotel. The following forms of insulation will be of assistance:

roof and wall insulation;

roof paint use light or white colour, or specialised solar coating to deflectsolar radiation;

building shading planting of trees around the sunny side of the buildingto provide shade for lower levels of the building.

6.2.2 Key card room control

Hotel key card control is one of the largest potential energy savings of all initiativesidentified during this program. Guest rooms are the largest energy consumers

in hotels due to air conditioning and lighting use by guests. Rooms are usually

unoccupied for a substantial amount of time but the air conditioning and lights are

normally left on by guests. Depending upon the policy of the hotel, the cleaners

sometimes turn off the air conditioning, lights and television.

Key card room control is a convenient way to turn off air conditioning and lighting

when the rooms are not occupied. Some 41/2 to 5-star rated hotels are opposed to

the concept of key card control as the room temperature is outside the comfort zone

when guests return to the room (warm in summer and cold in winter). Introducing key

card room control is recommended with either of the following two options:

option 1 turn off air conditioning and lighting when room is unoccupied.

option 2 turn off lighting only when room is unoccupied, and reset the roomtemperature to an acceptable temperature such as 26C in warmer monthsand 18C in cooler months.

6.2.3 Lighting systems

Lighting is one of the major energy consumers in hotels. However, lamp technology

is continually evolving, resulting in increased energy efficiency. There are also many

simple lighting control techniques that can be implemented to improve energy

efficiency or reduce energy wastage.

Major energy saving opportunities are:

Use of energy efficient lamps:

Incandescent lamps: change incandescent lamps to compact fluorescent lamps (CFL).

This can provide energy savings of up to 80 per cent. The cost of CFL is continually

dropping due to increased demand. The life of CFL is also much longer at around

6000 to 15,000 hours, compared to 1000 to 2000 hours for incandescent lamps.



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Dichroic lamps: replace dichroic lamps either with compact fluorescent or LED

lamps. A 50W dichroic lamp can be replaced by a 7W compact fluorescent or 2W

LED. The same fittings can be used for the new lamps, decreasing the installation

costs. A 2W LED lamp has a little less light output than a 50W dichroic lamp.

Fluorescent lamps: replace 36 W standard fluorescent lamps with 36W energy

efficient triphosphor tubes. The triphosphor tube provides around 30 per cent

greater light output than the 36W tube. The most efficient fluorescent lamps are

T5 lamps. These lamps require new electronic ballasts with a dimming option.

They are economically viable when a complete lighting refurbishment is undertaken.

High bay lamps: replace mercury vapour lamps by pulse-type metal halide or sodium

lamps. Low pressure sodium lamps have an orange colour light output and may not

be suitable for some applications.

Lighting level: over lighting wastes energy. It is important to measure the lux levelof areas and minimise these levels where necessary in order to meet AustralianStandards for the activities undertaken. If an area is over lit, de-lamping or dimmingmay be considered to reduce lighting levels. Australian Standards for lighting levelsfor different areas are shown in Table 9.3.

Lighting control

- Use energy saving voltage control for fluorescent lamps.

- Use timer control for areas which have set occupancy times.

- Use of motion detectors when lighting is not required continuously in areassuch as conference rooms.

- Use lux controllers in areas that receive ambient daylight through windows.These controllers can turn lamps off and on, or dim them depending on theambient daylight. This type of control is also called daylight compensation control.

Refer to section 9.1 for more information about how much you can save with energy

efficient lighting.

6.2.4 Hot water boiler

Hot water boilers are generally used in domestic hot water generation and

space heating. There are many energy saving opportunities in hot water systems.Some of these are:

Fuel switching replace electric heating systems with natural gas systems.This not only has cost benefits but also provides a reduction in associatedgreenhouse gas emissions.

Separate boilers keep the space heating hot water boiler separate fromthe domestic hot water boiler.

Switch off space heating boiler during warm weather.

Water temperature reduce the domestic hot water temperature settingto around 50-60C.

Use an energy efficient hot water boiler some of the new generation boilers

are designed with heat recovery from flue gases. This can improve energy efficiencyby around 15 per cent but can only be used in space heating. The cost of sucha system makes the conversion economically unattractive.

Use a VSD in hot water recirculation pumps this can reduce energy consumptionby around 40 per cent and is economically attractive.



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Energy saving initiative 6Energy saving initiative 6

Energy Wise Hotel TOOLKIT 25

6.2.5 Swimming pool

Hotel swimming pools use a substantial amount of energy through keeping the water

temperature warm and circulating water through the filter. There are two forms of heat

loss from a swimming pool and pool house:sensible and latent heat losses.

Sensible heat loss is due to temperature difference, such as the temperature

difference across the building envelope or the difference between make-up ventilation

air and exhaust air. Latent heat loss is caused by exhausting moisture evaporating

from the pool surface and/or by expending energy to dehumidify the air. Almost allthe heat loss from the pool itself is due to surface evaporation.

Hotels can reduce sensible heat loss by adjusting the indoor air temperature,

insulating the building and using heat exchangers. To reduce latent heat loss for indoor

pools, adjust temperatures and humidity, use a pool cover during unoccupied hours

and install a heat pump dehumidifier. Installing an efficient water heater and adjusting

the circulation pump's operating hours can also be effective measures.

A few energy saving ideas for your swimming pool:

As a no-cost step, investigate adjusting the pool temperature, indoor airtemperature and indoor relative humidity. It is possible to reduce the evaporationfrom a pool surface to a low level or even nil via this strategy.

Cover the pool consistently during unoccupied hours. A pool cover can resultin energy savings of 50 to 70 per cent and also saves water. Liquid insulationis available on the market however its success is questionable.

Install a solar pool heater; this will significantly reduce swimming pool heating costs.

Install a heat pump water heater and dehumidifier with heat recovery. A heat pumpwater heater may also include heat pump dehumidification and heat recovery.The dehumidification process recovers latent heat from condensing moisture inthe air and uses it to heat pool water. These heat pump dehumidifiers with heatrecovery are commercially available from many companies.

Reduce the circulation pump's operating hours when the pool is closedfor the season, and filtration can be reduced by as much as 50 per cent.

Use a properly-sized, energy-efficient circulation pump. The pump should not

be over-sized.

6.2.6 Lifts and escalators

Lifts and escalators typically use around four to eight per cent of total energy in hotels.

Although energy saving in lifts is not going to be as large as other areas of the hotel,

there is still scope for improving energy efficiency. Some of these energy saving

measures are:

reduction of standby power use by developing sleep mode;

no lifts on, or doors under power, when the lift is not in use;

use of efficient drives;

optimisation of counter weight; and

use of a variable speed drive with sensors in escalators. This can reduce energyconsumption by 20 per cent. However they are more economically viable whenpurchasing a new escalator.


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6.2.7 Energy conservation through control

Automation, control and optimisation is one of the major energy saving opportunities

in the hotel industry. Building management systems (BMS) are becoming more popular

in medium to larger hotels.

Building management system (BMS)

BMS are conventionally used for:

Time schedule allows for switching equipment such as lights, fans and chillerson and off at set times.

Direct digital control (DDC) of cooling and heating. DDC is the regulatory digitalcontrol algorithm which provides more accurate control than analogue systemsand hence opportunities to increase energy efficiency. A DDC control systemhas the potential to improve energy efficiency by up to 20 per cent from aconventional analogue system.

Energy management system (EMS)

The conventional BMS can be upgraded to EMS providing advance

and optimal control for:

chillers;

HVAC (heating, ventilation and air conditioning systems);

pumps;

cooling towers;

boilers; and

electricity demand.

Typically EMS can save energy between 20 to 50 per cent for chillers

and HVAC systems.

Refer to section 9.4 for more information.



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Involving staff and guests 7


Energy awareness program

This is a program to motivate staff and guests to conserve energy. The focus of the

energy awareness program should be to reduce the impact of climate change rather

than achieve cost savings.

There are two major types of educational programs:

1. Energy awareness training

This is for key technical and operational personnel who are energy coordinators and

energy champions. The duration of such a program is around four to six hours and

deals with:

basic understanding of energy;

energy and our environment;

how to improve the energy efficiency of hotels in general;

basic understanding of energy efficient operation for HVAC,boiler and lighting systems; and

energy efficient technology.

2. Energy awareness seminars

These are seminars designed to educate and motivate all staff. The seminars should

be short, imparting a basic understanding of energy consumption and the associated

environmental impacts with guidelines on how to improve energy efficiency through

behavioural and operational practices. The recommended course outline is:

a discussion about global Issues: energy and the environment;

benefits to the company and staff;

presentation about energy misuse based on historical analysis of users;

brief discussion of recommended energy saving opportunities, mainly throughoperational change;

personnel participation to develop methods of reducing energy consumption;

achievements in energy conservation and reduction in greenhouse gasemissions; and

clear messages that everyone can help reduce energy and greenhousegas emissions.

3. Guest motivation

Hotel guests can also be motivated to reduce energy use through displays and

stickers on energy and climate change and the commitment of the hotel to be green.


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Renewable energy 8


Renewable energy does not produce any greenhouse gas emissions.Renewable energy is energy produced from sources that areconsidered infinite (will not run out) and are essentially non-polluting.

The common renewable energy sources are: solar power using technologies that convert sunlight into electricity or

mechanical power such as photovoltaic cells or solar hot water systems;

wind power converting wind energy into more useful forms, such as electricity,using wind turbines;

hydro power using the force or energy of moving water in such systemsas hydroelectric schemes, tidal power, and wave power;

geothermal power generating energy from the heat stored beneath theEarth's surface; and

combined heat and power using an engine to simultaneously generate bothelectricity and useful heat.

The Renewable Energy Act 2001 requires a minimum amount of renewable energy

to be sold by each electricity retailer within Australia. There is a government rebate

available on photovoltaic solar power generation.

8.1 Go carbon neutral

Many businesses are finding their corporate image benefits from pledging to be

carbon neutral by a set date such as 2020.

Being a carbon neutral business means any greenhouse gases emitted to meet

energy needs are offset by absorbing greenhouse gas elsewhere. This is described

in more detail below.

The benefit of your hotel becoming carbon neutral is both in terms of improved

corporate image as well as being able to service a growing number of business clients

that have also pledged to become carbon neutral.


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8.2 How does a hotel become carbon neutral?

Step 1: reducing energy and travel needs

The best way a hotel can reduce its impact on climate change is to save energy.

This will make your hotel very efficient in delivering its services and reduce operating

costs. Travel in cars and aeroplanes needs to be calculated and reduced where possible.

Step 2: sourcing renewable energy instead of traditionalcoal-fired energy

Businesses are able to source renewable energy for some or all of their energy

needs from an accredited electricity supplier.

GreenPowerTM is more expensive than traditional energy and hotels need to

manage this expense. This may be managed by using the financials savings from

energy efficiencies or by phasing in GreenPowerTM gradually over an agreed

number of years.

GreenPowerTM is energy produced from renewable sources which is bought

by energy suppliers and provided to their customers. The purchase of GreenPower

means the production of greenhouse gases due to electricity manufacture is

non-existent, resulting in a decreased rate of global warming.

Many energy suppliers now provide GreenPower. Most suppliers offer a renewableenergy option, however it is important these are GreenPower approved products.

These approved products ensure the supplier meets stringent government

environmental and reporting standards, which ensures that you, the customer,

can be confident your money is going directly to helping the environment.

GreenPower is regulated by the GreenPower Auditor. Submission of regular

reports ensures confidence in the GreenPower program and provides transparency

for customers.

Step 3: Purchasing off-sets to absorb any remaininggreenhouse gases

If there are remaining greenhouse gas emissions after undertaking the above first

two steps these can be off-set by accredited programs that absorb carbon-dioxidesuch as tree-planting.

For example, there are online systems enabling travel kilometres to be

off-set by paying a small fee for trees to be planted locally to off-set the amount

of emissions your travel generated.




There are four primary energy technologies that hotels need tounderstand and manage efficiently. These are discussed in more

detail in this section:

1. lighting;

2. heating, ventilation and air-conditioning systems;

3. variable speed drives; and

4. energy management systems (EMS).

9.1 Lighting systems

Lights are a major energy consumer in hotels and accommodation services.

The energy efficiency of lamps has significantly improved over the last few years and

it is worth replacing older, inefficient lights with these better performing alternatives.

Not only will this save on energy bills but it will also save on maintenance time in

replacing bulbs.

The main types of lamps being used in hotels are:

dichroic lights;

incandescent lamps;

LED lamps;

compact fluorescent lamps; and

fluorescent tubes, mostly 36W.

Technology discussion 9



9.1.1 Dichroic lamps

Dichroic lamps are extensively used as downlights in receptions, foyers and corridors.

These are known as cool beam lights. They are high brightness lamps suitable for

display and special effect lighting.

Advantages:

excellent colour rendering;

instant start; lamp life 2000 to 5000 hours;

higher lumens than incandescent type;

excellent lumens maintenance; and

can be dimmed.

Disadvantages:

power loss in transformers create heat loss (50W lamps require transformerof 12W loss). The 12W power used by transformers only transforms electricityto heat in the space;

ultraviolet content of light can fade some surfaces;

voltage fluctuation can reduce lamp life. A slight increase in main voltagesupply can reduce lamp life by 50 per cent;

lamp cost is greater than incandescent; and

touching of the quartz lamp may lead to premature lamp failure.

9.1.2 Incandescent lamps

These are the original filament type lamp. They consist of a glass enclosure with inert

gas. Here most of the power consumed dissipates as heat and does not transform

to light.

Advantages:

they are cheapest of all lamps; and

dimmable.

Disadvantages:

they are the most inefficient lamps; and

the life of the lamps is very short between 1000 to 2000 hours.

The efficiency of these lamps varies from eight to 17 lm/W compared to 85 lm/W

for fluorescent lamps with a lifespan of 10,000 hours.

Due to its inefficiency these lamps are in the process of being phased out of the

market by government regulation. It is worthwhile reorganising your lighting to

provide for this inevitable regulatory requirement.


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9.1.3 LED lamps

LED (light emitting diode) lamps are a new technology which fit all twist and lock

fittings and can replace the 50W halogen twist and lock lamp.

Advantages:

the anticipated life is 30,000 to 50,000 hours; and

a 2W LED lamp can be considered to replace 50W dichroic lamps withoutchange of light fittings.

Disadvantages:

energy efficient LEDs are expensive; and

require constant voltage transformer.

This technology is expected to increase in popularity and usage in the near future.

9.1.4: Compact fluorescent lamps

A compact fluorescent lamp (CFL), also known as a compact fluorescent light bulb

or an energy saving light bulb, is a type of lamp designed to fit into roughly the same

space as an incandescent lamp, but with the advantages of a fluorescent lamp.

Many CFLs can directly replace an existing incandescent lamp.

Compared to incandescent lamps of the same luminous flux, CFLs have alonger-rated life and use less energy. The initial purchase price of a CFL is higher

than an incandescent lamp of the same output, although this cost may be quickly

recouped in energy savings assuming average bulb use.

Although CFLs do radiate a different spectrum of light than incandescent

lamps, recent technological advances have reduced that difference dramatically.

The light emitted by the best soft white CFLs available today is similar in quality

to standard bulbs.

The life of CFL is around 6000 to 15,000 hours compared to the 1000 to 2000

hours of an incandescent lamp.

An 11W CFL provides almost the same lumens (light) as a 60W incandescent lamp.

Normally they are 75 to 80 per cent more energy efficient than incandescent lamps.However they are around six to 10 times more expensive than incandescent lamps.

Recently CFL technology has improved and the lamps are now available as dimmable.

Dimmable CFL are much more expensive than non-dimmable.

CFL are also available as a down-light to replace dichroic lamps which are being used

extensively in hotel foyers and corridors. A 9W CFL can replace a 50W dichroic lamp

using the same fittings.

9.1.5 Standard fluorescent lamps

This is a glass tube lamp that is conventionally used in offices. The length of tube

varies with power. More information about standard fluorescent lamps is set out

in Appendix D.


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9.1.6 Maintaining lamps

Maintaining lamps is very important for energy efficiency. The light output decreases

with the operation hours of the lamp and dirt builds up in the shield

Light depreciation with lamp life.As the lamp gets older it reduces output.Therefore it is important to replace lamps as they get older.

Loss of light resulting from build up of dirt. Lamps should be maintainedand cleaned regularly. Figure 9.1 shows light reduction against clean lamp.

Figure 9.1 - Loss of light from dirt built up

9.1.7 Lighting level standard

In all spaces including hotels, actual lighting requirements depend on the activity

of an area. The Australian Standard AS 1680-2006 is as follows for various activities.

Table 9.1 - Recommended lighting level


Area Light level (Lux)

Office work 320

Store rooms and stock rooms 320

Kitchen 240

Entrance areas and waiting rooms 160

Corridors 40

Toilets 80

50

60

70

80

90

100

55

65

75

85

95

11109876543210

Expected loss of light resulting from dirt build-up

Time between cleaning (years)

%M

aintainedLight


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9.2 Heating, ventilation and air conditioning systems

As the heating, ventilation and air conditioning (HVAC) system is the major energy

user in a hotel, it is important to understand. The HVAC system delivers:

heating;

cooling; and

air circulation.

9.2.1 HeatingHeating can be provided by three different means:

Hot water (or steam) system the lowest energy cost system if natural gasis available and the most common heating system in older hotels.

Electric heating elements the most energy inefficient and high energy costsystem. Many hotels use electric heating systems which were historically installedas a convenient low capital cost system.

Heat pumps relatively new technology that is energy efficient. The energy costis similar to or slightly higher than gas-heated hot water systems. Consideringmaintenance and auxiliary equipment, heat pumps are one of the most overallcost-effective systems.

9.2.2 Cooling

There are different types of air conditioning systems. Each type of system has its

own advantages and disadvantages. Therefore they are selected based on their

application, capital cost and energy performance. However, in the past very little

consideration was given to energy efficiency. Capital cost is normally the dominant

factor in selecting and designing air conditioning systems. The most common

types of air conditioning systems are:

single zone systems;

reheat systems;

multi-zone systems;

dual duct systems;

induction systems;

variable air volume systems;

water source heat pump systems; and

air cooled heat pumps.

The cooling can be provided by:

Refrigeration system: this is the cooling media and requires a compressor formechanical compression or an absorber for an absorption-type cooling system.Electrical energy is being used for a compression-type system and thermalenergy as heat is required for an absorption system.

Evaporative cooling: this is a low energy intensive cooling system ideallysuitable in dry weather condition. It cools air by humidifying air and does not

need any refrigerant. Although it is around 80 per cent more energy efficientthan a refrigerated cooling system, it does not provide comfort levels as easilyas a refrigeration system and can be noisy and inconvenient.

Some HVAC systems do not have cooling towers. The condenser cooling is done

by blowing air over the condenser tubes. These are called air-cooled systems.


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Basics of an air conditioning system

Figure 9.2 - The schematic of a basic air conditioning system

Figure 9.2 is a typical guest room air conditioning system. This is a four pipe system,

with two pipes for chilled water and two pipes for hot water (the hot water piping is

not shown).

Chilled water is circulated by chilled water pumps and hot water is circulated by hot

water pumps.

In some hotels the guests rooms are heated by electric heating elements replacing

the hot water coils in the fan cool unit.

Economy cycle

Economy cycle reduces energy costs. The energy saving can be in the order of 25 to

30 per cent in Melbournes climate. Since an economy cycle brings in more fresh air,

the system may require slightly more cleaning of air filters.

The cost of an economy cycle can be as low as $3000 plus additional costs for duct

modification, if required.

For more information about an economy cycle refer to Appendix E.


COOLING

TOWER

CONDENSER

CHIL LER

CONDI TONED SPACE

COOLING

WATER

PIPING

COMPR ESSOR

CHIL LED

WATER

PIPING

AIR F ILTERS

INSUL ATED

RETURN AIR

DUC TING

COULD B E AIR

COOLED

COOLING

WATER PUMP

CHIL LED

WATER PUMP

AIR

HANDLING

UNI T

INSUL ATED

SUPP LY AIR

DUCT ING

AIR OUTLETS

SUPP LY

AIR FANCHILLED WATER

COOLING CO IL


37/53



Economiser

It is possible to cool the fresh air by exhaust air with an air-to-air heat exchanger.

Types of heat exchangers are:

rotary heat exchange wheel;

plate heat exchanger; and

heat pipe system.

Expected energy savings from this system are between three and 15 per cent.

The higher the amount of fresh air used in the HVAC system, and the more extreme

the weather conditions, the higher the energy savings will be.

Figure 9.3 - Typical economiser

9.2.3 Heat pump technology

Heat flows naturally from higher to lower temperature. However heat pumps use

external energy to force heat flow in the opposite direction. All heat pumps require

a vapour compression cycle which is a mechanical refrigeration system.

There are two types of heat pumps, described below.

COP is the coefficient of performance which is the ratio of energy

output/energy input.

1. Conventional air-cooled heat pump

A conventional heat pump is commonly known as a reverse air conditioner which

can cool and heat. The COP of conventional air-cooled heat pumps for space

heating is shown in the table below.

Table 9.2 - COP of conventional air condenser heat pumps

COP is the ratio of power output to input and is the efficiency of the refrigeration

cycle. Higher the COP more energy efficient it is.

Return Air 22 C

Spill Air 27 C

Fresh Air 25 C

Fresh Air 30 C

Size (kWr) COP heating COP cooling

7 3.28 2.78

26 3.63 2.94

32 3.67 2.95


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2. Water source heat pump

This is a very energy efficient way to heat and cool hotel rooms. There is no central

compressor and instead there are central water heaters and a heat rejection (cooling

tower) system. Each room has a fan coil unit refrigerant compressor. During the

heating cycle the hot gas is used to heat the room (utilising condensing heat).

The hot water from the boiler is used to cool water from the evaporator.

Heat recovery: it is possible to recover some heat during cooling time to produce

hot water that can be used as domestic hot water.

Energy efficient comfort condition of HVAC system

The comfort level of an air conditioned space varies with the following variables:

gender of occupants as females generally feel colder than males;

activity within the building;

relative humidity and dry bulb temperature; and

air movement.

The comfort condition is not a single temperature level but a zone, which is shown

in the shaded area of Figure 9.4 below. It is recommended that HVAC systems

should be operated at a higher temperature in this zone when cooling and a lowertemperature in this zone when heating.

During the cooling cycle, every 1oC temperature rise will reduce energy consumption

by five to 10 per cent.

Similarly during the heating cycle, every 1oC temperature decrease will reduce energy

consumption by five to 10 per cent.

Figure 9.4 - Psychrometric chart of comfort zone


0.002

0.006

0.004

0.010

0.008

0.012

0.014

0.016

0.018

10 13 16 18 21 24 27 29 32 35 38

Operative Temperature,C

HumidityRatio

-5

-10

5

0

10

15

20

Dew

PointTemperature,

C

90

80

70

60

50

40

30

20

10% RH

Data based on ISO 7730 and ASHRAE STD 55

Upper Recommended Humidity Limit, 0.012 humidity ratio

0.5 PMV Limits

1.0 Clo 0.5 Clo


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0

1

2

3

4

5

6

7

20253035404550

Speed (Hz)

Power Factor

Power

Power(kw)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

8 0.8

15

PowerFactor

9.3 Variable speed drive

Air conditioning motors run at a fixed speed although the demand for air flow or water

reduces in lesser cooling load conditions. As the air or water flow demand reduces

the damper or valve throttles to restrict flow. Throttling is an irreversible process

(that is, wastes energy which can never be recovered).

It is possible to vary the speed of the motors through change of frequency of

electricity supply. To deal with the problem of throttling, a variable speed drive (VSD)

can be installed. This allows the controller to change the speed of the drive insteadof throttling and avoids the loss of energy.

Figure 9.5 - Power requirement for throttling with fixed speed and VSD drive with no throttling

Variable speed drives are one of the biggest and most economically viable energy

saving opportunities in HVAC systems for supply and return air fans, chilled and

condenser water pumps and chiller compressors.

Figure 9.6 - Power VS fan speed of a typical AHU fan



0

20

40

60

80

100

120

120100806040200

Volume flow rate %

Damper control

Speed control

Comparative power requirements. Speed and Damper control of fan duty

Fan

Power%


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Figure 9.7 - Power VS fan speed of a typical cooling tower fan

Figure 9.8 - Power VS pump speed of a typical water circulation pump


0

02

04

06

08

10

12

14

20253035404550

Speed (Hz)

Power(kw)

0

10

20

30

40

50

60

70

20253035404550

Speed (Hz)

Power(kw)


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9.4 Energy management system (EMS)

An energy management system (EMS) is a computer-based energy monitoring

and optimal control system for building services. Normally the system is based on

conventional BMS (building management systems). The functionality of a building

EMS is as follows:

Economy cycle control.An economy cycle is illustrated in Section 9. Althoughthere are stand alone economy cycle controllers available, they do not operate tooptimal efficiency. An energy management control system provides superior controlsuch as enthalpy-based control, which provides additional energy and cost savings.Refer to Appendix E for more information.

Optimal start of HVAC. Space heating and cooling always requires time topreheat or cool the space before it reaches comfort conditions. Normally suchpre-cooling or heating time is preset however this can be changed to be a functionof ambient temperature. On a hot day, the hotel requires more pre-cooling timethan on a more temperate day. Optimum start time resets pre-cooling time toavoid keeping the space cooled longer than required and hence reducing wasteof energy.

Night purge.This involves pre-cooling a building at night especially during hottermonths when the outside air temperature is low, thus reducing the energy requiredfor building pre-cooling.

Feed forward variable speed drive control is intelligent speed control of supplyand return air fans. The conventional speed control of a fan is based on a presetsupply pressure. When the HVAC system is not designed as a variable air volume(VAV) system, the conventional feedback control is not viable. The speed set pointis determined by a function of area cooling load.

Chiller and cooling tower optimal control.The chiller is used to provide buildingcooling and is one of the major energy consumers in a hotel. Larger to medium sizehotels typically have a centralised chiller system to provide chilled water for cooling.The chiller plant may consist of multiple chillers, which depend on the intelligence ofthe supervisory control for energy efficiency. The energy efficient functions of thesecontrollers are as follows:

- chiller optimal selection selects the combination of chillers to run at any giventime to meet the cooling load with minimum energy consumption. At low loadcondition it also cycles the operation of chillers;

- chiller loading and control ensures the optimum loading of each chiller to reduceenergy consumption;

- chilled water temperature reset. Conventionally the chilled water temperatureis set to a low temperature of 6C to 7C. When the cooling load is low, the setpoint of the chilled water system can be increased. Every 1C increase in chilledwater temperature reduces energy consumption by around 2.5 per cent.

- cooling/condenser water temperature reset. Similar to chilled water temperaturereset, the condenser water temperature increases the energy efficiency of boththe chiller and cooling tower. The decrease of condenser water temperaturereduces energy consumption by around 2.5 per cent per degree watertemperature reduction.




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Optimal pump control. Optimal pump control is useful when multiple pumps areused for chilled water, hot water or domestic water supply to the hotel. It involvesinstalling a VSD on one of the pumps and selecting the number of pumps tooperate, therefore controlling the supply pressure. Energy savings of 20 to40 per cent are achievable through this technique.

Hot water boiler

- optimal start/stop of boiler.

Demand management system- demand and energy monitoring;

- demand control; and

- energy sub-metering.

How much can you save with an EMS?

Chiller system:

reduce energy consumption by 20 to 40 per cent; and

reduce run hours by up to 30 per cent.

HVAC:

reduce fan energy cost by 40 to 50 per cent.

DDC control:

reduce cooling and heating load by up to 20 per cent.

House-keeping:

This is to monitor and track energy use and key performance indicators as well

as various energy efficiency parameters. As a rule of thumb, the saving is expected

to be around one to five per cent of the overall energy consumption.




A corporate policy should be set to meet corporate goals andstandards. An example of a corporate policy is set out below.

Energy is one of our organisations major ongoing costs. Its impact on climatechange is a great concern to us. As a good corporate citizen we as a company

set the following policies:

1. Reduce energy consumption of each hotel by 10 per cent per year for the

next three years.

2. Energy efficiency should be considered in purchasing and maintaining

all equipment.

It is the responsibility of each individual employee to use energy wisely and efficiently.

Appendix A: Example of corporate policy A



1. Energy and our environment

Greenhouse gas emissions cause global warming which is detrimental

to our environment.

The earth is covered by a blanket of gases in the atmosphere which allows light

energy from the sun to reach the earths surface. This light energy is converted

to heat energy. These gases are called greenhouse gases.

Most of the heat is re-radiated towards space but some is trapped by greenhouse

gases in the atmosphere. This is a natural effect, which keeps the earths temperature

at levels necessary to support life.

The problem we face is that human actions particularly burning fossil fuels and land

clearing are generating more greenhouse gases. These additional gases trap more

heat and raise the earths surface temperature.

This is known as the enhanced greenhouse effect it causes global warming and

is changing our environment.Reducing the use of energy reduces the power generation where the majority

of greenhouse gases are generated.

Figure B.1: Heat balance

Appendix B: Energy and our environment B

Atmosphere emits long

wave radiation (60%)

Transfer of heat between

Earths surface and

Atmosphere (zet zero)

Earths surface emits long

wave radiation (9%)

The increase in greenhouse gases within the atmosphere

traps more heat, and raises the Earths surface temperature.

Incoming solar

radiation (100%)

Increased used of fossil fuels

Earths surface reflects

solar radiation (6%)

Convection to atmosphere (31%)


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2. Global warming

Some of the effects of global warming are:

a rise in sea level causing coastal damage;

an increase in the likelihood of extreme weather conditions such as droughts,floods and cyclones;

health impacts because of the spread of tropical-borne diseases, the increaseof flooding and other such climate changes;

damage to ecosystems and species diversity; and

damage to agricultural output and food supply, and an increase in the earthssurface temperature causing heat stress and other damage.

3. Saving our environment

It is essential that all efforts are made to reduce greenhouse gas emissions.

Hotels can help by:

reducing energy use; and

using environmentally friendly refrigerants. The two most commonenvironmentally friendly refrigerants are:

- CFC 123: Environmentally friendly but not accepted by energy and

atmospheric credit #4, which is regarded as the current standard forenvironmentally friendly refrigerant. This gas has low global warmingpotential and high energy efficiency.

- HFC 134A: Environmentally friendly.

4. Measurement of greenhouse gas

Greenhouse gas is measured in carbon dioxide equivalent (CO2 e) which takes

into account the global warming potential of each of the greenhouse gases.

Energy related:

- Stationary: this is the source of greenhouse gas emission from energy usedby stationary equipment such as a boiler, generator or power station.

- Transport: greenhouse gas emission from cars, trucks and other vehicles,which Is used for the transport industry.

Non-energy related:

- Waste: this is the source of greenhouse gas emission from all types of wastes,such as paper, textile, wood and other sources.



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Figure B.2: Greehouse gas emissions for stationary energy

Figure B.3: Greenhouse gas emissions for transport energy

Figure B.4: Municipal solid waste

Appendix B: Energy and our environment B


0

100

200

300

400

Coke Briquettes

(brown)

Coal

(brown)

Coal

(black)

Fuel Oil Diesel LPG Natural

Gas

Electricity

kg

CO2-e/GJ

0

20

40

60

80

100

Petrol Diesel Fuel Oil LPG

kgCO2-e/GJ

0

0.5

1.0

1.5

2.0

2.5

3.0

Paper Textiles Wood GardenFood

kgCO2-e/GJ


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For more information about the measurement of greenhouse gases refer to the

AGO Factors and Methods Workbook.


Global warming potential (GWP)

1. Carbon dioxide CO2 GWP = 1

2. Methane CH4 GWP = 21

3. Nitrous oxide N2O GWP = 310

4. Hydro fluorocarbons (HFCs) GWP = 140 - 11,700

5. Per fluorocarbons (PFCs) GWP = 65,000 9,200

6. Sulphur hexafluoride GWP = 23,900


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What is power factor?

The power factor is the ratio of true or active power (kW) over the apparent power (kVA).

Figure C.1- Diagrammatic representation of power factor

The causes of reactive power are inductive devices such as AC motors, induction

furnaces, arc welders, fluorescent and mercury vapour lighting. These cause a time

lag between current and voltage cycles which causes large reactive currents.

How to correct power factor

Use of synchronous motor; or

Use of capacitor bank.

The required sizing of a power factor controller is calculated as follows:

Cos1 = Current power factor

Cos2 = Desired power factorkVAR required = kW x (tan-11 - tan-12)

Appendix C: Power factor correction equipment C


kVAR 1

kVAR 2

kVA 1

kW

kVA 2

1

2


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A typical luminaries or fixture for fluorescent lamps is shown in thefigure below. This consists of:

housing;

reflector;

lamps;

ballast; and

shielding.

Figure D.1 - Typical luminare of a fluorescent lamp

The type of reflector, lamps and shielding can all contribute to light efficiency.

In a fluorescent lamp there is no filament as in incandescent lamps. Instead,

cathodes at each end send currents through mercury vapour sealed in the tube.

Ultraviolet radiation is produced as electrons from the cathodes knock mercury

electrons. The tubes are lined with phosphor to turn the radiation to visible light.

This requires ballasts which are in every fixture and regulate the voltage during start up.

The light output of these lamps varies from 69 to 104 Lumens/W. TL5 is the latest

fluorescent lamp technology and with electronic ballasts produces 3300 lumens

with 33W.

There are two types of ballasts:

electromechanical the standard ballast loss is around 10W; and

electronic which can be fixed or dimmable ballasts. The electronic ballastslosses are generally less than 2W.

Appendix D: Detail of a fluorescent lamp D



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When the ambient air enthalpy is less than that for return air it iseconomical to introduce as much fresh air as possible to cool thebuilding. However, this is restricted by the return air duct filter.

Therefore a motorised damper is required to regulate the fresh air make-up.

An increased supply of fresh air is more hygienic and comfortable. The economy

cycle of an air conditioner reduces energy costs. The energy saving can be in the

order of 25 to 30 per cent in the Melbourne climate. Since the economy cycle

brings in more fresh air, the system may require slightly more cleaning of air filters.

The cost of an economy cycle can be as low as $3000 plus additional costs for duct

modification, if required.

Figure E.1: Economy cycle

There are two types of economy cycle which are:

temperature-based; and

enthalpy-based.

Appendix E: Air conditioning economy cycle E

energy wise hotels

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