Chapter 7 : Energy Conservation for Money Saving

According to Macao’s Statistics and Census Service, the commerce, restaurant and hotel sectors consume 16,995 thousand litres of gas oil & diesel, 4,794 thousand litres of fuel oil, 12,640 tonnes of liquefied petroleum gas (LPG) and 526 million kWh of electricity in 2003, representing 18% of gas oil & diesel, 37% of fuel oil, 45% of LPG and 30% of electricity. Hotel energy consumption depends on many factors, such as geographical location, size, class, equipment, system, occupancy and age of facility. Electricity use accounts for 60 to 70% of the utility costs of a typical hotel. Many hotels have discovered that this cost is controllable, without sacrificing guest comfort, by using energy more efficiently. Typically, annual electricity use for air conditioning may account for over 50% of total electricity used in a hotel. The second largest electricity user are lighting systems, normally in the range of 25-35% of total electricity consumption in a hotel. From the results of the Macao Hotel Environmental Survey 2003, the hotel industry has adopted some energy conservation equipment and facilities as shown in Figure 7.1. Among them, energy efficient lighting systems are the most commonly adopted means of energy conservation.

Why Conserve Energy?

(Photo 7.1) Typically, annual electricity use for air conditioning may account for over 50% of total electricity used in a hotel. (Source: Environmental Protection Department, Hong Kong).

Figure 7.1 Adoption of Energy Conservation Equipment and Facilities. (Source : Macao Hotel Environmental Survey 2003)

The most direct benefit of energy conservation is, of course, a saving of expenses in electricity and fuel consumption. In addition, reducing energy consumption can protect the environment. The energy used in Macao is mostly derived from fossil fuels such as petroleum and natural gas, etc. All these fuels are valuable natural resources and will eventually be used up in the future. Therefore, saving energy means conservation of such resources.

The process of converting fossil fuels into energy also creates certain pollution problems. For instance, using coal to produce electricity (fuel oil, gas oil and diesel are used to produce electricity in Macao) generates polluted air emissions, wastewater, chemical waste, solid waste, etc. Consequently, energy conservation can help reduce the environmental pollution generated from the energy production process.

Ways You Can Help

The primary goal of energy management is the improvement of efficiency in two key areas:

• Operator efficiency: ability to understand, operate and maintain the hotel’s equipment and systems in an energy-efficient manner.

• Building, equipment and systems efficiency: ability to choose energy efficient design, equipment and systems.

Action plan for energy efficiency

• Carry out an energy audit for the hotel, which will show you major energy consumer costs and where savings can be made.

• Install submeters to facilitate the accurate energy audits (It is well worth doing this, as lack of feedback on actions taken within individual departments is often the cause of failure of savings programmes).

• Compare your total and individual consumption figures with hotel industry benchmarks to determine saving potential.

• Using the energy-audit results, establish realistic goals for each department and the entire hotel.

• Communicate to all employees management’s commitment and explain clearly the objectives and goals.

• Appoint an energy co-ordinator (usually the engineer), define responsibility within each department and develop an effective communication system.

• Encourage staff members to give suggestions or feedback on the energy conservation plan.

• Establish a monitoring and targeting system.

• Provide training to staffs to make sure they operate and maintain equipment in an energy-efficient manner.

(Photo 7.2) Carry out an energy audit for the hotel.	(Photo 7.3) Provide training to staff members to make sure they operate and maintain equipment in an energy-efficient manner.

a. Guest Rooms and Other Guest Facilities

• Turn off / set back lights and air conditioning systems in unoccupied banquet rooms and other areas.

(Photo 7.4) Replace incandescent and old fluorescent bulbs with energy-saving fluorescent bulbs in guest rooms.

(Photo 7.5) In day time, switch on spot light instead of chandelier with high energy consumption.

(Photo 7.6) Heat generated from the cooling process in the air coniditioning system can be recovered through a heat recovery system to produce heat water for use in guest rooms and public areas.

• Turn off all lights when leaving unoccupied guest rooms.

• Replace incandescent and old fluorescent bulbs with energy-saving fluorescent bulbs and electronic ballasts in guest rooms, public areas, back-of-house, grounds/exterior, etc.

• Install dehumidifiers to save energy if humidity is a problem rather than keeping the air conditioning system on 24 hours a day.

• Use energy-saving air conditioners in all guest rooms.

• During periods of low occupancy, arrange guests in groupings and shut off unoccupied areas.

• Use key cards for room power supply.

• Adopt motion-sensor systems to turn the power off in store rooms and jacuzzis, when they are vacant.

• Post up energy saving reminders.

• Replace a small refrigerator in each guest room with a larger refrigerator in the corridor for guests to share.

b. Housekeeping and Laundry

• Establish a housekeeping procedure regarding required air conditioning settings in occupied and unoccupied guest rooms.

• Establish a procedure that requires housekeepers to leave guest room window coverings closed or partially closed to cool the room.

• Provide scales to weigh the laundry before it is washed.

• Provide signs in the laundry to inform the staff of how much laundry can be washed in each machine.

• Use washers and dryers only with full loads.

• Provide a system in the laundry to recycle waste heat.

• Ensure water temperature, amount of water, suds, rinse levels and steam pressure are in accordance with the specifications of the washing machine manufacturer.

• Use high efficiency washers (e.g. Tunnel washers).

c. Restaurant and Kitchen

• All walk-ins should have plastic curtains to retain cold air.

• Establish a controlled access program (i.e. locks on walk-in doors and scheduled access periods) to prevent walk-in doors from being opened throughout the day.

• Always keep doors of freezer / cold room tightly closed when not in use.

• Do not heat up several heating elements if only one is needed.

• Assign responsibility for turning off lights and equipment to a member of each shift.

• Install a heat recovery unit on the dishwasher to recover heat from the rinse cycle.

• Install suitably-sized stoves that meet operational requirements to minimise energy wastage.

• Use high-efficiency cooking devices.

• Clean refrigerator coils and air conditioner filters regularly to help these appliances run more efficiently.

• Routinely inspect and maintain freezers or cold rooms, e.g. defrost regularly, to maintain their energy efficiency.

• Use air-miser hoods that use outside air as make-up air instead of discharging conditioned inside air.

• Install a timer for the kitchen exhaust hood that turns off the system when the kitchen is closed.

(Photo 7.7) Heat recovery for central air conditioning system.	(Photo 7.8) A heat recovery unit on the dishwasher to recover heat from the rinse cycle.
	(Photo 7.9) A heat pump reuse waste heat, recover the energy lost to the atmosphere to preheat / cool air or water.

(Photo 7.10) Improve boiler efficiency to save energy consumption.	(Photo 7.11) Make full use of daylight.

d. Engineering and Maintenance

• Monitor, record and analyze energy and water consumption regularly.

• Set benchmarks or goals for energy consumption.

• Prepare periodic energy usage reports for management.

• Establish an energy management system for air conditioners.

• Install lighting controls (timers or occupancy sensors) to turn off lights in unoccupied areas such as storage rooms, employee rest rooms, walk-in coolers, etc.

• Use glazed windows to conserve energy.

• Establish a system to reuse waste heat, recover the energy lost to the atmosphere to preheat / cool air or water, e.g. install a heat pump.

• Decrease lighting level where possible and remove unnecessary fluorescent tubes.

• Make full use of daylight.

• Install automatic door closers on doors connecting air-conditioned space to non-air conditioned space.

• Improve chiller, cooling tower, heater and boiler efficiency.

• Install water / sea water cooled chiller to replace air cooled chiller.

• Heat recovered from the air-conditioning chillers can be used to pre-heat hot water.

• Implement free cooling – the outside air damper opens up to 100% to provide cooling if the exterior temperature is lower than that of the interior spaces.

• Install a combined heat and power (CHP) system fuelled by natural gas, reducing the annual energy cost and reducing boiler maintenance costs.
• Install chiller sequencing controls and variable speed drives on air handling units, exhaust and supply fans.

• Schedule HVAC equipment and systems to time of day, week or holiday operation. Install timers. Shut off individual units in unoccupied areas. Guest rooms can be controlled by house-keeping maids when making up rooms after check-out.

• Operate chillers, boilers, pumps, and cooling tower equipment in accordance with actual loads. Shut off equipment not required for the load.

• Operate steam boilers at two pressure levels – at higher pressure during laundry operation and at lower pressure for kitchen, hot water and heating when laundry is closed.

• Use variable speed secondary system pumps instead of differential pressure control. Install inverter to operate pumps in accordance with load. Convert system with three-way control to two-way, and modulate pump operation instead of constant full volume water flow.

• Convert constant air volume (CAV) systems to two-speed or variable frequency-controlled high efficiency motors, or variable air volume (VAV) system.

• Install a solar thermal energy system to produce hot water.

• Consider alternative renewable energy sources.

Box 7.1 – Automated Control System

(Photo 7.12) Replace air cooled chiller with sea water cooled chiller.

(Photo 7.13) A computerised building management system can efficiently control air-conditioning, lights, fire services, lifts, security and plumbing.

(Photo 7.14) Use solar energy to generate electricity for lighting.

There are various types of computerised control within hotels. Check-in, room entry, entertainment and communications, heating, ventilation and air-conditioning, fire and security systems, room service and even replenishment of the minibar can all be automated and controlled centrally.

The Building Management System (BMS) helps to save energy and operational costs through efficient control of the equipment. A good Building Management System, interfaced with some of the following key control systems, can cut the building’s energy costs by 10-25%.

• The facility management system – to ensure plant efficiency and essential maintenance is carried out by generating accurate maintenance schedules based on equipment performance.

• The energy management system – is able to carry out a comprehensive electrical power and thermodynamic performance analysis, the system is able to optimise peak electrical demand, significantly reducing costs.

• Automatic control of temperature, relative humidity, pressure and equipment operation.

• The telephone system – to enable services to be automatically dialed and staff paged when problems occur and to allow remote access to systems for prompt diagnosis and response.

• Independent electronically-controlled systems such as elevators, chillers, boilers, cold rooms and freezers, etc.

• The fire system – to log all records, pass on alarm status to the telephone system when required, communicate with the security system, shut down all necessary plant and equipment and activate any required plant during an alarm situation.

• The security system – to control access to and within the building.

Advantages:

• Reduced installation costs (only one infrastructure being required rather than several).

• Services and systems can be centrally controlled from head office.

• Different systems can more readily communicate and share information.

• Dial-up (remote) access into the system is possible.

Box 7.2 – Combined Heat and Power (CHP)

The sequential production of electricity and useful heat energy from the same primary energy fuel is called combined heat and power (CHP).

In a typical co-generation project, an engine fuelled by natural gas, diesel or light oil or reciprocating engine is used to drive a generator, and the heat that is rejected from the engine is used for producing hot water and winter heating, etc. The savings result from the produced electricity and the simultaneous use of free heat energy, which would otherwise have been lost to the atmosphere.

The analysis for technical and economic feasibility is extremely important, as a CHP system that produces significant savings in one hotel may be completely inappropriate for another one.

Case Studies

Case study 7.1 – A Hotel in Hong Kong, China

A hotel in Hong Kong owned by a Japanese company has implemented several energy saving measures:

Key card master switch
The hotel estimated that approximately a third of its guests forgot to turn off the master switch controlling electrical units when leaving the room. The hotel installed a key card-controlled master switch to replace the button, which automatically ensures all electrical units are off when rooms are vacant.

Economic and environmental benefits:
The hotel estimates that the key card system brings a saving of HK$2.36 per day per room. Switches cost HK$165 per unit. The payback period is 70 days.

Maintaining indoor temperatures
Daily thermometer readings ensure that indoor temperatures are maintained at 20ºC degrees in summer and at
21-22ºC in winter.

Reducing boiler operating hours and water temperatures
The hot water boilers are switched off between 01:00 and 05:00. Water temperature has been reduced from 60ºC to 55ºC – hot enough for personal use and to prevent legionella growth.

Economic and environmental benefits:
In 1995, these measures combined brought the hotel a 6% reduction in electricity costs, and over a 9% reduction in fuel oil costs, which translated into savings of about HK$512,000.

Readjustment of gas equipment
The hotel has installed control technologies that maintain the correct ratio of gas and air in the kitchen stoves. The hotel works with the Hong Kong & China Gas Company to ensure that all gas equipment is adjusted in accordance with the Company’s specifications.

Economic and environmental benefits:
Gas consumption is reduced by 11% and associated costs are reduced by 6% each year.

Case study 7.2 – A Hotel in London, U.K.

Changes to the hotel have meant great financial savings for the group in the past few years. Some of these changes include:

Some of the benefits of the system are:
- Air-conditioning temperatures in all public areas are now accurately controlled, whereas previously constant adjustments had to be made.
- Chillers and heaters, which used to be started manually and ran for many more hours than necessary, now start automatically as required.

Case study 7.3 – A Hotel in Shenzhen, China

A Hotel in Shenzhen, China has adopted the following innovative energy saving practices and gained a wide publicity for its environmental performance.

Frequency converter for the automatic control of the central air conditioning system - a variable frequency for power supply can be provided depending on the size of the loading. It not only has saved energy consumption but also extend the lifespan of the machinery units.

Escalator with infra-red sensor – After installation of the infra-red sensor, the escalator can be switched on only automatically when in use.

Heat recovery for central air conditioning system - Heat generated from the cooling process in the air coniditioning system can be recovered through a heat exchange to produce 50-60ºC water for use in guest rooms and public areas. Also, it has greatly reduced the loading of the condenser, reducing energy consumption of the whole air conditioning system by 15-20%.

Lighting system – T5 high energy efficient fluorescent tubes replace the traditional incandescent and old fluorescent lighting system.

Those measures have cost about HK$2 million and combined, they brought the hotel HK$500,000 reduction in annual electricity costs.

Case study 7.4 – Hotels in Macao, China

Two hotels in Macao have entered into an agreement with private energy service companies (ESCO). For the installation of energy saving devices, the ESCO recommended an energy-saving solution to be paid through savings. The hotel did not pay any up-front money for the investment. The ESCO then received a portion of the money saved to cover all project costs over a contract term of a fixed number of years. The ESCO bears the risk of being unable to get back the money through savings.

Other energy conservation measures adopted in Macao hotels are as follows:

(Photo 7.15) Frequency converter for pump control can save energy consumption and extend the lifespan of the machinery units.

• Chiller sequencing controls

• Scaling / fouling control measures for condenser and cooling tower in chiller applications

• Power factor correction devices at main switchboard

• Frequency converter for pump control

• Heat pump

• Heat exchange for energy recovery

• Computerised building management system

• When door is closed, light is turned off automatically