Online version: PDF - DTIE
Online version: PDF - DTIE
Online version: PDF - DTIE
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
102<br />
UNIT 4: ENVIRONMENT MANAGEMENT SYSTEMS<br />
• Background ventilation systems such as trickle vents;<br />
• Rapid ventilation systems such as extractor fans;<br />
• Ducted systems including heat recovery.<br />
Low-Energy Lighting<br />
Low-energy lighting is easy to install and can reduce energy costs by 10-15%. Lowenergy<br />
lamps include compact fluorescent (CLFs), fluorescent tubes, and tungsten<br />
halogens.<br />
CLFs last about 8 times longer than tungsten halogen lamps and use about 25%<br />
less energy for the same light output. Tungsten halogen lamps are about 50%<br />
more efficient than standard lamps and last twice as long. All energy-efficient<br />
lighting offers the advantage of dimmer switches, which allow control of light<br />
output.<br />
Coverings and Coatings<br />
In warmer climates, weatherproof coverings should be finished off with sunreflecting<br />
paints to reduce solar heat gain. Similarly, pale shades used for<br />
decorating exteriors and interiors reduce heat gain and increase light reflection.<br />
Heat Recovery<br />
Hospitality properties can achieve substantial savings by recovering sensible and<br />
latent heat from kitchen, laundry and swimming-pool exhaust systems, boiler<br />
flues, and condensed heat recovery. This heat can be channelled back for space<br />
or water heating. Heat recovery requires the installation of heat exchangers to<br />
separate the heat from its source (water, gas or combustion products) and transfer<br />
it to where it can be reused – the water or space heating system. The most costeffective<br />
heat-recovery systems for hospitality businesses are usually sensible<br />
heat exchangers such as run-around coils and thermal wheels.<br />
The feasibility of heat recovery depends on:<br />
S<br />
E<br />
C<br />
T<br />
I<br />
O<br />
N<br />
2<br />
• The temperature of the waste heat in the air or water;<br />
• Where the waste heat is to be used, which should be closely connected<br />
to the source of the waste heat;<br />
• Purchasing and operating costs of the heat-exchange unit: the cost of<br />
the heat recovered should be higher than the purchasing and operation<br />
of the heat-exchange unit.<br />
COMMON QUESTION What is the difference between sensible heat and latent<br />
heat?<br />
Sensible heat is the heat associated with a change in temperature. Latent heat<br />
is associated with a change in state such as from liquid to gas.<br />
Building Energy Management Systems (BEMS)<br />
BEMS are computer-based energy-management systems which provide for the<br />
integrated control of thermostats, boilers, and zone controllers, each zone having<br />
its own heating, cooling and lighting units. They therefore enable different areas<br />
of a property to be controlled separately and even shut down when not in use.